EP2593979A1 - Transluscent conductive substrate for organic light emitting devices - Google Patents
Transluscent conductive substrate for organic light emitting devicesInfo
- Publication number
- EP2593979A1 EP2593979A1 EP11732463.2A EP11732463A EP2593979A1 EP 2593979 A1 EP2593979 A1 EP 2593979A1 EP 11732463 A EP11732463 A EP 11732463A EP 2593979 A1 EP2593979 A1 EP 2593979A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- layer
- electrode
- coating
- scattering
- translucent conductive
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
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Classifications
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
- H10K50/00—Organic light-emitting devices
- H10K50/80—Constructional details
- H10K50/805—Electrodes
- H10K50/81—Anodes
- H10K50/816—Multilayers, e.g. transparent multilayers
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
- H10K50/00—Organic light-emitting devices
- H10K50/80—Constructional details
- H10K50/85—Arrangements for extracting light from the devices
- H10K50/854—Arrangements for extracting light from the devices comprising scattering means
Definitions
- the present invention relates to a translucent conductive su bstrate for Organic Light Emitting Devices (OLEDs), to the method for producing said translucent conductive substrate, to an Organic Light Emitting Diode incorporating said translucent conductive su bstrate and to the method for prod ucing sa id Orga n ic Light Emitting Device.
- OLEDs Organic Light Emitting Devices
- An Organic Light Emitting Device comprises at least an organic layer which is put between electrodes, a voltage is applied between the electrodes to inject holes and electrons, which are allowed to recombine in the organic layer, thereby an light is emitted by a light-emitting molecule in the course of a transition from a n excited state to a lower energy state.
- the Orga nic Lig ht Emitting Device is used for lighting display, backlight and lighting applications.
- OLEDs Sta rting from the su pport, OLEDs a re d ivided i nto th ree categories, bottom-emitting, top-emitting and transparent OLEDs.
- the bottom-emitting OLED uses a transparent or semi-tra nspa rent bottom electrode, the lig ht is emitted th roug h a transparent support.
- a top-emitting OLED uses a transparent or semi-transparent top electrode through said light is emitted, in other words the light is not emitted through the support.
- transparent OLED T-OLED
- T-OLED uses transparent or semi-transparent electrodes on both sides of the device in such a way that the light can be emitted both through the top and the bottom electrode.
- the expression "bottom electrode” is understood to denote the electrode which is the closest to the support.
- a bottom emitting OLED comprises at least one transparent electrode generally made from indium-doped tin oxide (ITO), a transparent support for su pporting the tra nspa rent electrode a nd a reflective cou nter electrode wh ich is generally made from calcium, silver or aluminium.
- the transparent support is made, for example, of glass, ceramic glass or polymer film.
- the refractive indexes of the different constituents of the OLED are in the range of 1.6-1.8 for the organic layers of the light- emitting device, 1.6 to 2.0 for the ITO layer, 1.4 to 1.6 for the supporting substrate and 1.0 for the outside air.
- Organic light-emitting devices are ma n ufactu red with a good i nternal lig ht efficiency. Th is efficiency is expressed in terms of internal q uantu m efficiency (IQE).
- Internal quantum efficiency represents the ratio between the number of photons obtained divided by the number of electrons injected. It lies in the order of 85%, even close to 100%, in known organic light-emitting devices.
- the efficiency of these devices is clea rly li mited by the losses associated with i nterface reflection phenomena due to the differences between the refractive indexes of the materials constituting the layers defining the interfaces.
- the losses as a result of reflection (R) occur at the interfaces and cause a reduction in external quantum efficiency (EQE).
- the external quantum efficiency is equal to the internal quantum efficiency minus the losses through reflection. As a result of a ll these combined losses, it is commonly accepted that the external quantum efficiency is generally in the range of 20% to 25% of the internal quantum efficiency.
- ITO Indium-doped tin oxide
- indium resources are limited, which in the short term will lead to an inevitable increase in production costs for these devices.
- ITO Indium-doped tin oxide
- thick ITO is generally more crystalline, causing an increase in the microscopic roughness of the surface, which must then be polished occasionally for use within organic light-emitting devices.
- ITO material may have sufficient conductivity because the pixels size is small, typically on the order of 1 mm or less.
- the cond uctivity of such transparent ITO electrodes can be insufficient for applications that require much larger emitting area such as lighting panel.
- indium present in organic light- emitting devices has a tendency to d iffuse i nto the orga n ic pa rt of these devices resulting in a reduction in the shelf and operating lifetime of these devices.
- Document WO 2008/029060 A2 d iscloses a tra nspa rent su bstrate, i n particular a transparent glass substrate, having a multilayer electrode with a complex stacking structure comprising a metal conductive layer and also having a base layer combin ing the properties of a barrier layer and an a ntireflective layer.
- This type of electrode enables layers with a low resistivity and a transparency at least equal to the electrode of ITO to be obtained, and these electrodes can be advantageously used in the field of large-surface light sources such as light panels.
- these electrodes allow the quantity of indium used in their fabrication to be reduced or even suppressed entirely.
- an antireflective layer in the form of a barrier layer is used, the solutions proposed in docu ment WO 2008/029060 A2 do not seek in a ny way to optimize the a mount of lig ht emitted by an OLED limiting the losses associated with interface reflection phenomena. Furthermore, a colour variation of the light emitted by the OLED depending on the viewing angle is also observed.
- an aim set by the present invention is to provide a translucent conductive substrate for OLED that allows an increase in the amount of light transmitted in the forward direction th rough the substrate to be obtained, in other words an increase in the amount of light emitted by an OLED that it is incorporated into, i.e. in the case of a monochromic radiation .
- the term "monochromic” is understood to mean that a single colour (e.g . red, green, blue, white ...) is perceived by the eye without this light being monochromatic as such.
- monochromic radiation denotes a radiation covering a wavelength range and not a simple wavelength.
- the said translucent conductive substrate must be easy to manufacture.
- An aim set of the present invention in at least one embodiment, is to provide a translucent conductive su bstrate for OLED that allows to decrease, even to suppress, the amount of materials based on Indium, Indium oxide or a mixture thereof used to fabricate the transparent electrode which is comprised in the translucent conductive substrate.
- Another aim set of the present invention in at least one embodiment, is to provide a translucent conductive substrate that allows a decrease of the colour angular dependency of the light emitted by an OLED incorporating said translucent conductive substrate.
- the present invention is directed to a translucent cond uctive substrate for Organic Light Emitting Device comprising :
- a transparent support, ⁇ a scattering layer formed over the transparent su pport a nd comprising a glass which contains a base material having a first refractive index for at least one wavelength of light to be transmitted and a plurality of scattering materials dispersed in the base material and having a second refractive index different from that of the base material,
- a transpa rent electrode formed over the scattering layer, said electrode comprising at least one metal conduction layer, preferably a single metal conduction layer, and at least one coating having properties for improving the light transmission through said electrode, wherein said coating has a geometric thickness at least more than 3.0 nm and at most less than or equal to 200 nm,
- the substrate according to the invention allows from one hand, an increase in the amount of light emitted by a OLED in the forward direction that incorporates it, i.e. in the case of monochromic radiation, and on the other hand, a decrease of the colour variation of the light emitted by the OLED depending on the viewing angle.
- the substrate according to the invention can be used with any known type of layered stacking structure forming the organic part of the OLED that emits white light.
- the translucent conductive substrate of the present invention comprises a transparent support.
- the support will be considered to be transparent when it exhibits a light absorption of at most 50%, even at most 30%, preferably at most 20%, more preferred at most 10% at wavelengths i n the visi ble l ig ht ra nge .
- the translucent conductive substrate according to the invention comprises a transparent support having a refractive index at least equal to 1.2, preferably at least equal to 1.4, more preferred at least equal to 1.5 at a wavelength of 550 nm.
- n pport is also u nderstood to mean not only the support as such, but also any structure comprising the support as well as at least one layer of a material with a refractive index, n mate riai / close to the refractive index of the support, n SU p POrt , in other words
- n SU pp 0rt -n mate nai l represents the absolute value of the difference between the refractive indexes.
- a silicon oxide layer deposited on a soda-lime-silica glass support can be cited as example. Th is layer is used to protect the glass surface against ageing before other layer would be deposited.
- the function of the su pport is to support and/or protect the electrode.
- Th e su pport ca n be mad e of g lass, rig id p lastic mate ria l (e . g . orga n ic g la ss, polycarbonate) or flexible polymer films (e.g. polyvinyl chloride (PVC), polyethylene terephthalate (PET), polypropylene (PP), polytetrafluoroethylene (PTFE)).
- the support is preferably rigid.
- the support is a polymer film, this preferably has a high refractive index, wherein the refractive index of the support (n SU pp 0rt ) has a value at least equal to 1.4, preferably at least equal to 1.5, more preferred at least equal to 1.6.
- n SU pp 0rt represents the refractive index of the support at a wavelength of 550 nm.
- the advantage provided by using a support with a high refractive index is that it allows the amount of emitted light to be increased with the same substrate structure.
- the support is made of glass, e.g. a sheet of glass, this preferably has a geometric thickness of at least 0.1 mm.
- the term "geometric thickness" is understood to mean the average geometric thickness.
- Glasses are mineral or organic. Mineral glasses are preferred. Of these, soda-lime-silica glasses that are clear or are bulk or surface coloured are preferred. More preferred, these are extra-clear soda-lime-silica glasses.
- extra-clear denotes a glass containing at most 0.020% by weight of the glass of total Fe expressed as Fe 2 0 3 and preferably more than 0.015% by weight. Because of its low porosity, the glass has the advantage of assuring the best protection against any form of contamination of an OLED comprising the translucent conductive substrate according to the invention.
- the refractive index of the glass has a value at least equal to 1.4, preferably at least equal to 1.5, more preferred at least equal to 1.6, most preferred at least equal to 1.7. Nevertheless, for reasons of cost, the refractive index of the glass, n suppor t, preferably has a value in the range of between 1.4 and 1.6. More preferred, the refractive index of the glass has a value of about 1.5. n suppor t represents the refractive index of the support at a wavelength of 550 nm.
- the glass support comprises at least one barrier layer on the face of the glass on which the scattering layer is deposited.
- the barrier layer comprises at least one compound selected from the following: silicon oxide, aluminium oxide, titanium oxide, mixed oxide of zinc-tin, mixed oxide of zinc- aluminium, silicon nitride, aluminium nitride, titanium nitride, silicon oxynitride, aluminium oxynitride.
- the substrate of the present invention comprises a scattering layer, wherein said scattering layer is formed over the transparent support and comprises a glass which contains a base material having a first refractive index for at least one wavelength of light to be transmitted and a plurality of scattering materials dispersed in the base material and having a second refractive index different from that of the base material.
- the scattering layer is formed by depositing a glass powder on the glass substrate by a method such as coating and firing it at a desired temperature.
- the said scattering layer has the base material having a first refractive index and a plurality of scattering materials dispersed in the above-mentioned base material and having a second refractive index different from that of the above-mentioned base material.
- a materia l (base materia l) havi ng a ma i n su rface coated a nd having a high light transmittance may be used.
- As the base material a glass, a crystallized glass, a translucent resin or a translucent ceramic may be used.
- an inorganic glass such as soda lime glass, borosilicate glass, non-alkali glass, low-alkali glass or quartz glass may be used.
- the plurality of scattering materials is formed in the inside of the base material.
- the tra nslucent conductive su bstrate is so that the scattering materials are selected from pores, precipitated crysta ls, materia l pa rticles havi ng a d ifferent chem ica l composition than base material, phase-separated glass or mixtures from at least two thereof.
- the scattering materials are preferably selected from precipitated crystals, material particles having a different chemical composition than base material, phase- separated glass or mixtures from at least two thereof.
- the scattering materials are most preferably selected from phase-separated glass.
- the material particle as used herein as scattering material means a small solid material .
- the translucent conductive substrate is so that the material particles used as scattering materials are selected from crystalline particles, amorphous particles or at least a mixture thereof.
- the material particles used as scattering materials may have the sa me or different chemical compositions, preferably the particles have the same chemical composition .
- the material constituting the particle is preferably selected from a ceramic material .
- the ceramic is selected from a ceramic oxide (Ti0 2 , Zr0 2 , Sn0 2 , Zn0 2 , Si0 2 , Sb 2 0 3 , Al 2 0 3 , ZrSi0 4 , preferably Ti0 2 , Zr0 2 , Al 2 0 3 , Si0 2 ), a ceramic non-oxide (carbides, borides, nitrides, silicides) or a composite ceramic (combinations of oxides and non-oxides ceramics).
- the particles are in the form of fillers (i .e., colloidal particles, aggregates, clusters,...)- In case of using the particles as the scattering materials, it is desirable to make the scattering layer by two layers.
- the particle doesn't exist in the scattering layer in the upper layer.
- the pore means an air or gas material trapped within the base material.
- the phase-separated glass means a glass composed of two or more kinds of glass phases.
- the size of the scatteri ng materia l i nd icates a diameter of a void.
- the translucent conductive substrate according to the invention is so that the distribution of the scattering materials in the scattering layer decreases from the inside of the scattering layer towards the face of the scattering layer opposite to the transparent support on which said scattering layer is deposited.
- the main surface of the scattering layer is required to be smooth.
- the scattering materials protrude from the main surface of the scattering layer.
- the scattering materials are not present within 1.0 ⁇ , preferably 0.5 ⁇ , most preferably 0.2 ⁇ from the main surface of the scattering layer, in other words the face of the scattering layer opposite to the transparent support on which said scattering layer is deposited.
- the scattering layer is not limited to a single layer but may be two or more layers.
- the scattering layer comprises a first layer part and a second layer part formed on the first layer part
- the solid materia ls are used as the scattering materials, it is more preferable that the second layer part does not have the scattering materials except for an interface between the first and second layer parts. Due to the existence of the solid materials on the surface of the scattering layer has the possibility of causing the short circuit.
- the su rface of the scatteri ng layer has cu rvatu re su rface with swell .
- the swell means cycle R- a is at least 10 ⁇ .
- the size of swell (roughness) means Ra is within the range from 0.01 ⁇ to 5 ⁇ . It is preferable that R- a is more than 10 ⁇ and Ra/R- a is with i n a ra nge from 1.0*10 "5 to 1.0*10 _1 , causing mirror function of an anode electrode to reduce. It is more preferable that R- a is more than 50 ⁇ and Ra/R- a is within a range from 1.0*10 "4 to 3.0*10 "2 .
- the Ra and the R- a used herein mean values calculated based on ISO 4287: 1997 (JIS B0601:2001), taking the short wavelength cutoff value as 25 ⁇ and the long wavelength cutoff value as 2.5 mm.
- is prefera bly 0.2 or more,
- is more preferably 0.2 or more,
- the geometrical thickness of the scattering layer is in the range of 2 ⁇ to 100 ⁇ , preferably in the range of 10 ⁇ to 60 ⁇ .
- the refractive index of the scattering layer must be equivalent to or higher than the refractive index of the transparent electrode material based on a transparent conductive oxide such as ITO.
- the refractive index of the base material is only required to exceed for at least one portion (for example, red, blue, green or the like) in the emission spectrum range of the scattering layer. However, it exceeds preferably over the whole region (430 nm to 650 nm) of the emission spectrum range, and more preferably over the whole region (360 nm to 830 nm) of the wavelength range of visible light.
- the inventors have surprisingly found that this condition is not required with an electrode having a multilayered structure.
- the refractive i n dex of the scatteri n g layer is determined as follow, a glass having the same composition as the scattering layer is prepared and the refractive index of said glass is measured using a Shimadzu Device Corporation measurement apparatus brand name KPR2000 using a prism method.
- a scattering layer using a high refractive index glass as the above-mentioned h ig h l ig ht tra nsmitta nce materia l a nd the gas materia l, na mely the pores, as the scatteri ng material is desirable.
- the refractive index of the base material is desirably as high as possible, so that the high refractive index glass is preferably used as the base material.
- one or two or more kinds of components selected from P 2 0 5 , Si0 2 , B 2 0 3 , Ge 2 0 and Te0 2 can be used, as network formers, and one or two or more kinds of components selected from Ti0 2 , Nb 2 0 5 , W0 3 , Bi 2 0 3 , La 2 0 3 , Gd 2 0 3 , Y 2 0 3 , Zr0 2 , ZnO, BaO, PbO and Sb 2 0 3 as high refractive index components.
- an alkali oxide, an alkaline earth oxide, a fluoride or the like may be used within the range not impairing characteristics required for the refractive index.
- Specific glass systems include a B 2 0 3 -ZnO-La 2 0 3 system, a P 2 0 5 -B 2 0 3 -R' 2 0-R"0-Ti0 2 -Nb 2 0 5 -W0 3 -Bi 2 0 3 system, a Te0 2 -ZnO system, a B 2 0 3 -Bi 2 0 3 system, a Si0 2 -Bi 2 0 3 system, a Si0 2 -ZnO system, a B 2 0 3 -ZnO system, a P 2 0 5 -ZnO system and the like, wherein R' represents an alkali metal element, and R" represents an alkaline earth metal element.
- the scattering layer uses a glass conta ining 15 to 30 mol% of P 2 0 5 , 5 to 25 mol% of Bi 2 0 3 , 5 to 27 mol% of Nb 2 0 3 , 10 to 35 mol% of ZnO and 5 mass% or less of the alkali metal comprising Li 2 0, Na 2 0 and K 2 0 in terms of total amount thereof.
- P 2 0 5 is an essential component because it is a network former which is a skeleton of this glass system, and is a glass stabilizing element.
- it is preferably 15 mol% or more, and more preferably 18 mol% or more.
- the refractive index decreases to result in failure to achieve the object of the invention. Accordingly, it is preferably 30 mol% or less, and more preferably 28 mol% or less. Therefore, the amount of P 2 0 5 in the glass is advantageously comprised within the range of two of the preceding values, more advantageously within the range from 18 mol% to 28 mol%.
- Bi 2 0 3 is a com ponent i m provi n g the refractive i n dex, a nd ca n be introduced into the glass in relatively high amounts while keeping stability of the glass. Accordingly, the content is more than 5 mol%, preferably more than 10 mol%, and more preferably more than 13 mol%. However, excessive introduction thereof poses the problem of fabricating a rather coloured glass decreasing therefore the transmittance. Accordingly, the content is 25 mol% or less, preferably 23 mol% or less, and more preferably 20 mol% or less.
- the amount of Bi 2 0 3 in t h e g l a ss i s advantageously comprised within the range of two of the preceding values, preferably comprised within the range from 10 mol% to 23 mol%, more preferably from 13 mol% to 20 mol%.
- Nb 2 0 5 is an essential component improving the refractive index and also having an effect of enhancing weather resistance at the same time. Accordingly, the content is 5 mol% or more, preferably 7 mol% or more, and more preferably 10 mol% or more. On the other hand, when the content is too high, devitrification increases resulting in failure to obtain a glass. Accordingly, the content thereof is 27 mol% or less, preferably 20 mol% or less, and more preferably 18 mol% or less.
- the amount of Nb 2 0 5 in the glass is advantageously comprised with in the range of two of the preced i ng val ues, prefera bly with in the ra nge from 7 mol% to 20 mol%, more preferably within the range from 10 mol% to 18 mol%.
- ZnO is a component improving the refractive index and decreasing the glass transition temperature. Accordingly, the content is 10 mol% or more, preferably 16 mol% or more, more preferably 18 mol% or more. However, when it is excessively added, devitrification of the glass increases resulting in failure to obtain a homogeneous glass. Accordingly, the content is 35 mol% or less, preferably 30 mol% or less, and more preferably 27 mol% or less. Therefore, the amount of ZnO in the glass is advantageously comprised within the range of two of the preceding values, preferably with in the range from 16 mol% to 30 mol%, more prefera bly from 18 mol% to 27 mol%.
- the alkali metal oxides ( 2O) such as Li 2 0, Na 2 0 and K 2 0 has an effect of improving meltability to decrease the glass transition temperature and concurrently an effect of enhancing affinity with the glass substrate to increase adhesion.
- the total amount of alkali metal oxide is preferably less than 5% by mass, more preferably less than 2% by mass, particularly preferably not contain substantially.
- Ti0 2 is an optional component improving the refractive index.
- the content is preferably up to 8 mol%.
- B 2 0 3 is an optional component as a component which is added into the glass, thereby improving resistance to devitrification and decreasi ng the therma l expansion coefficient.
- the refractive index decreases. It is therefore preferably 17 mol% or less.
- W0 3 is a n optiona l component i m provi ng the refractive i ndex a nd decreasing the glass transition temperature to decrease the firing temperature.
- the content thereof is preferably up to 20 mol%.
- Te0 2 is an optional component having the effect of lowering the glass transition temperature while suppressing the excessive rise of thermal expansion. Accordingly, the content is preferably up to 7 mol%.
- Ge0 2 is a n optiona l component havi ng the effect of a high refractive index. Accordingly, the content is preferably up to 7 mol%.
- Sb 2 0 3 is a n optiona l component having the effect of su ppressi ng the colour. Accordingly, the content is preferably up to 2 mol%.
- Alkaline Earth Metal Oxides MgO, CaO, SrO and BaO are optional components improving the stability of the glass. However, excessive introduction thereof results in reducing the thermal expansion coefficient and refractive index. Accordingly, the total content thereof is preferably up to 10 mol%. Even if a component other than the above-mentioned components, we may add for the purposes of refining or an improvement of solubility, as long as it does not deviate from the efficiency of the present invention.
- Such components include, for example Si0 2 , Al 2 0 3 , La 2 0 3 , Y2O3, Gd 2 0 3 , Zr0 2 , Ta 2 0 3 , Cs 2 0 and may also contain transition metal oxides. Their content is preferably less than 5 mol% in the total, more preferably less than 3 mol%, particularly preferably not contain substantially.
- the glass of the present invention su bstantia lly does not contain lead oxide, less likely to cause environmental pollution.
- the substrate of the present invention comprises a transparent electrode, wherein said electrode can act as an anode or conversely as a cathode, depending on the type of OLED in wh ich sa id electrode is inserted into.
- a coating having properties for improving light transmission is understood to denote a coating whose presence in the stacking structure forming the electrode leads to an increase in th e a mou nt of l ig ht tra nsm itted th roug h th e su bstrate, e . g . a coati n g havi ng antireflective properties.
- an OLED incorporating the substrate according to the invention emits a higher amount of light compared to an OLED of the same type, but having a classic electrode (e.g. : an ITO layer) deposited on an identical support to that of the substrate according to the invention, the increase in the amou nt of light emitted is characterised by a higher luminance value, irrespective of the colour of the emitted light.
- the geometric thickness of the coating for improving light transmission must have a thickness at least greater than 3.0 nm, preferably at least equal to 5.0 nm, more preferred at least equal to 7.0 nm, most preferred at least equal to 10.0 nm.
- a geometric thickness of the coating for improving light transmission of at least more than 3.0 nm allows a metal conduction layer, particularly of silver, that has a good electrical conductivity to be obtained.
- the geometric thickness of the coating for improving light transmission advantageously has a thickness of less than or equal to 200.0 nm, preferably less than or equal to 170.0 nm, more preferred less than or equal to 130.0 nm, and the advantage of such thicknesses lies in the fact that the production process of said coating is quicker. Therefore, the geometric thickness of the coating for improving light transmission is advantageously comprised within the range from 5.0 nm to 200.0 nm, preferably from 7.0 nm to 170.0 nm, more preferred from 10.0 nm to 130 nm.
- the geometric thickness of the metal conduction layer is at least equal to 6.0 nm, preferably at least equal to 8.0 nm, more preferred at least equal to 10.0 nm at most equal to 29.0 nm, preferably at most equal to 27.0 nm, more preferred at most equal to 25.0 nm, most preferably at most equal to 22.0 nm. Therefore, the geometric thickness of the metal conduction layer is advantageously comprised within the range of two of the preceding values, preferably within the range from 6.0 nm to 29.0 nm, preferably from 8.0 nm to 27.0 nm, more preferred from 10.0 nm to 25.0 nm.
- the translucent conductive substrate is such that the transparent electrode formed over the scattering layer, said electrode comprising a single metal conduction layer and at least one coating having properties for improving the light transmission through said electrode, wherein said coating has a geometric thickness at least more than 3.0 nm and at most less than or equal to 200 nm, and said coating comprises at least one layer for improving light transmission and is located between the metal conduction layer and the scattering layer, on which said electrode is deposited, wherein the optical thickness of the coating having properties for improving the light transmission, T D i, and the geometric thickness of the metal conduction layer, T M E, are linked by the equation:
- T ME T ME _o + [B * sin (n*T D i/T D i_o)]/(n S upport) 3
- T M E_O B and T D i_ 0 are constants with T M E_O having a value in the range of 10.0 to 25.0 nm, B having a value in the range of 10.0 to 16.5 nm and T Di 0 having a value in the range of 23.9 * n Di to 28.3 * n Di nm, with n Di representing the refractive index of the coating for improving the light transmission at a wavelength of 550 nm and n SU pp 0rt represents the refractive index of the support at a wavelength of 550 nm.
- the optical thickness of a layer is obtained by multiplying the geometric thickness of said layer by the refractive index of the material constituting said layer.
- the value of the refractive index taken is the one at a wavelength of 550nm.
- an electrode stacking structure based on the selection made by the equation linking the geometric thickness of the metal conduction layer, T M E, to the optical thickness of the coating having properties for improving the light transmission, T D i, leads to an increase of the amount of light emitted by the OLED.
- the tra nsl ucent cond uctive su bstrate according to the invention is such that the transparent electrode formed over the scattering layer, said electrode comprising a single metal conduction layer and at least one coating having properties for improving the light transmission th rough said electrode, wherein said coating has a geometric thickness at least more than 3.0 nm and at most less than or equal to 200 nm, and said coating comprises at least one layer for improving light transmission and is located between the metal conduction layer and the scattering layer, on which said electrode is deposited, wherein the optical thickness of the coating having properties for improving the light transmission, T D i, and the geometric thickness of the metal conduction layer, T M E, are linked by the equation :
- T ME T M E _o + [B * sin (n*T D i/T D i_o)]/(n S s) 3
- T M E_O B a nd T D i_ 0 are constants with T M E_O having a va lue in the range of 10.0 to 25.0 nm, B having a value in the range of 10.0 to 16.5 nm and T Di 0 having a value in the range of 23.9 * n Di to 28.3 * n Di nm, with n Di representing the refractive index of the coating for improving the light transmission at a wavelength of 550 nm and n ss represents the refractive index of the stacking structure comprising the support and the scattering layer at a wavelength of 550 nm, where
- n SU pport representing the refractive i ndex of tra nspa rent su pport at a wavelength of 550 nm
- n scaUe ringiayer representing the refractive index of the scattering layer at a wavelength of 550 nm
- l support representing the geometrical thickness of the support
- l SC attenngiayer representing the geometrical thickness of the scattering layer.
- the selection of the electrode stacking structure based on the equation linking the geometric th ickness of the metal conduction layer to the optical thickness of the coating having properties for improving the light transmission, T D i can be adapted in order to take into account the refractive index of the scattering layer (e.g., when the optical thickness of the scattering layer is more than or equal to 0.1 % of the optical thickness of the support).
- the tra n sl ucent cond u ctive su bstrate according to the invention in such that the refractive index of the coating for improving light transmission is higher than the refractive index of the stacking structure comprising the support and the scattering layer at a wavelength of 550 nm.
- the translucent conductive substrate according to the invention is such that the support has a refractive index, n SU pp 0rt , in the range of between 1.4 and 1.6 at a wavelength of 550 nm and that the electrode is such that the optical thickness of the coating having properties for improving light transmission, T D i, and the geometric thickness of the metal conduction layer, T M E, are linked by the equation:
- T ME T ME _o + [B * sin (n*T D i/T D i_o)]/(n S upport) 3
- T M E_O B and T D i_ 0 are constants with T M E_O having a value in the range of 10.0 to 25.0 nm, preferably 10.0 to 23.0 nm, B having a value in the range of 10.0 to 16.5 nm and T Di 0 having a value in the range of 23.9 * n Di to 28.3 * n Di nm, with n D i representing the refractive index of the coating for improving the light transmission at a wavelength of 550 nm and n supP ort representing the refractive index of transparent support at a wavelength of 550 nm.
- T M E_O B and T DI 0 are such that T M E_O has a value in the range of 10.0 to 23.0 nm, preferably 10.0 to 22.5 nm, more preferred 11.5 to 22.5 nm, B has a value in the range of 11.5 to 15.0 and T D i_o has a value in the range of 24.8 * n Di to 27.3 * n Di nm.
- constants T M E_o B and T D i_o are such that T M E_O has a value in the range of 10.0 to 23.0 nm, preferably 10.0 to 22.5 nm, more preferred 11.5 to 22.5 nm, B has a value in the range of 12.0 to 15.0 and T Di 0 has a value in the range of 24.8 * n Di to 27.3 * n Di nm.
- the translucent conductive substrate according to the invention is such the support has a refractive index value, n SU pport in the range of 1.4 to 1.6 and is such that the geometric thickness of the metal conduction layer is at least equal to 6.0 nm, preferably at least equal to 8.0 nm, more preferred at least equal to 10.0 nm and at most equal to 22.0 nm, preferably at most equal to 20.0 nm, more preferred at most equal to 18.0 nm, the geometric thickness of the metal conduction layer is advantageously comprised within the range of two of the preceding values, preferably within the range from 6.0 nm to 22.0 nm, more preferably from 8.0 nm to 20.0 nm, the most preferably 10.0 nm to 18.0 nm, and wherein the geometric thickness of the coating for improving light transmission is at least equal to 50.0 nm, preferably at least equal to 60.0 nm and at most equal to 130.0 nm, preferably at most equal to 11
- the translucent conductive substrate according to the invention is such that the support has a refractive index value, n SU pp 0rt in the range of 1.4 to 1.6 and is such that the geometric thickness of the metal conduction layer is at least eq ua l to 16.0 n m, preferably at least eq ual to 18.0 n m, more preferred at least equal to 20.0 nm and at most equal to 29.0 nm, preferably at most equal to 27.0 nm, more preferred at most equal to 25.0 nm, the geometric thickness of the metal conduction layer is advantageously comprised within the range of two of the preceding values, preferably within the range from 16.0 n m to 29.0 n m, more preferred from 18.0 nm to 27.0 nm, the most preferred from 20.0 nm to 25.0 nm, and wherein the geometric thickness of the coating for improving light transmission is at least equal to 20.0 nm and at most equal to 40.0 nm.
- the use of a thick meta l cond uction layer com bi ned with a n opti m ised th ickness of the coati ng for improving light transmission allows OLEDs that have a high luminance to be obtained as well as a translucent conductive substrate, in which the electrode has a lower surface resistance expressed in ⁇ /D .
- the translucent conductive substrate according to the invention is such that the refractive index of the material forming the coating for improving light transmission (n Di ) is higher than the refractive index of the support (n SU p PO rt ) (n Di > n SU p PO rt ), preferably n Di > 1.2 n SU p PO rt , more preferred n Di > 1.3 n SU pport / most preferred n Di > 1.5 n SU pp 0 rt .
- the refractive index of the material forming the coating (n Di ) has a value ranging from 1.5 to 2.4, preferably rang ing from 2.0 to 2.4, more preferred ranging from 2.1 to 2.4 at a wavelength of 550 nm.
- n Di is given by the equation :
- — x i where m represents the layer n umber in the coating, n x represents the refractive index of the material forming the x "th layer sta rting from the support, l x represents the geometric thickness of the x "th layer, l Di represents the geometric thickness of the coating .
- n x represents the refractive index of the material forming the x "th layer sta rting from the support
- l x represents the geometric thickness of the x "th layer
- l Di represents the geometric thickness of the coating .
- the use of a material with a h igher refractive index allows a higher amount of emitted or transmitted light to be obtained.
- the advantage provided is all the more significant as the difference between the refractive index of the coating for i m provi ng the l ig ht tra nsm ission a nd the refractive i ndex of the su pport is substantial.
- the material forming at least one layer of the coating for improving light transmission comprises at least one dielectric compound and/or at least one electrically conductive compound .
- dielectric compound is understood to mean at least one compound selected from the following : the oxides of at least one element selected from Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Ni, Zn, Al, Ga, In, Si, Ge, Sn, Sb, Bi as well as a mixed oxide of at least two thereof nitrides of at least one element selected from boron, aluminium, silicon, germanium as well as a mixed nitride of at least two thereof; silicon oxynitride, aluminium oxynitride, mixed oxynitride of silicon-aluminum; silicon oxycarbide.
- the d ielectric compou nd prefera bly comprises a n yttriu m oxide, a titanium oxide, a zi rcon i u m oxide, a hafn i u m oxide, a n iobi u m oxide, a tantalum oxide, a zinc oxide, a tin oxide, an aluminium oxide, an alu minium nitride, a silicon nitride and/or a silicon oxycarbide.
- the term "cond uctive" is u nderstood to relate to a compou nd chosen from the following : oxides under-stoichiometric in oxygen and doped oxides of at least one element selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Zn, Al, Ga, In, Si, Ge, Sn, Sb, Bi as well as a mixed oxide under-stoichiometric in oxygen or a doped mixed oxide of at least two thereof; - doped nitrides of at least one element selected from boron, aluminium, silicon, germanium as well as a mixed doped nitride of at least two thereof; doped Si oxycarbide; the doping agents preferably comprise at least one of the elements chosen from Al, Ga, In, Sn, P, Sb, F. In the case of silicon oxynitride the doping agents comprise B, Al and/or Ga.
- the cond uctive compou nd prefera bly comprises at least ITO a nd/or doped Sn oxide, wherein the doping agent is at least one element chosen from F and Sb, and/or doped Zn oxide, wherein the doping agent is at least one element chosen from Al, Ga, Sn , Ti .
- the inorgan ic chemica l compound comprises at least ZnO x (where x ⁇ 1) and/or Zn x Sn y O z (where x + y > 3 and z ⁇ 6) .
- Zn x Sn y O z prefera bly comprises at most 95% by tota l weig ht of the meta ls present in the layer.
- the meta l con d u ction layer of the electrode form i n g a pa rt of the translucent conductive substrate according to the invention mainly assures the electrical conduction of said electrode. It comprises at least one layer composed of a metal or a mixture of metals.
- the generic term "mixture of metals" denotes the combinations of at least two metals in the form of an alloy or doping of at least one metal by at least one other meta l, wherein the metal and/or the mixtu re of metals comprises at least one element selected from Pd, Pt, Cu, Ag, Au, Al.
- the metal and/or mixture of metals preferably comprises at least one element selected from Cu, Ag, Au, Al.
- the metal cond uction layer comprises at least Ag in pu re form or alloyed to another metal.
- the other metal preferably comprises at least one element selected from Au, Pd, Al, Cu, Zn, Cd, In, Si, Zr, Mo, Ni, Cr, Mg, Mn, Co, Sn. More preferred, the other metal comprises at least Pd and/or Au, preferably Pd.
- the inventors have fou nd that the geometric thickness of the metal conduction layer must be at least equal to 6.0 nm in order to obtain a good conductivity of the electrode, in other words a low electrical resistance.
- the coating for improving the light transmission of the electrode forming a part of the translucent conductive substrate according to the invention comprises at least one additional crystallisation layer, wherein, in relation to the support, said layer is the layer fu rthest removed from the stacking structu re forming said coating .
- This layer allows a preferred growth of the metal layer, e.g. of silver, forming the metal conduction layer and thus allows favourable electrical and optical properties of the metal conduction layer to be obta i ned . It comprises at least one i norga n ic chemica l com pou nd .
- the i norga n ic chemical compound forming the crystallisation layer does not necessarily have a h igh refractive index.
- the inorganic chemical compound comprises at least ZnO x (where x ⁇ 1) and/or Zn x Sn y O z (where x + y > 3 and z ⁇ 6).
- Zn x Sn y O z preferably comprises at most 95% by weight of zinc, the percentage by weight of zinc being expressed in relation to the total weight of the metals present in the layer.
- the crystallisation layer is preferably composed of ZnO. Since the layer having properties for improving light transmission has a generally greater thickness than is usually encountered in the field of multilayer conductive coatings (e.g. low emission type coating), the thickness of the crystallisation layer must be ada pted or i ncreased to provide a meta l cond uction layer with good conduction and very low absorption.
- the geometric th ickness of the crystallisation layer is at least equal to 7% of the total geometric th ickness of the coating for improving light transmission and preferably 11%, more preferred 14%.
- the geometric thickness of the layer for improving light transmission must be reduced if the geometric thickness of the crysta llisation layer is i ncreased in order to comply with the relation between the geometric thickness of the metal conduction layer a nd the optica l th ickness of the coating for improving light transmission.
- the crystallisation layer is merged with at least one layer for i mprovi ng l ig ht tra nsm ission form i ng the coati ng for improving light transmission.
- the coating for improving lig ht transmission comprises at least one additional barrier layer, wherein, in relation to the scattering layer, said barrier layer is the layer closest to the stacking structure forming said coating .
- Th is layer in pa rticula r a llows the electrode to be protected from any contamination by the migration of alkaline substances coming from the support, e.g . made of soda-lime-silica glass, or from the scattering layer and thus enables the service life of the electrode to be extended.
- the barrier layer comprises at least one compound selected from the following : titanium oxide, zircon ium oxide, alumin ium oxide, yttrium oxide as well as a mixed oxide of at least two thereof; mixed oxide of zinc-tin, zinc-aluminium, zinc-titanium, zinc-indium, tin-indium; silicon nitride, silicon oxynitride, silicon oxycarbide, silicon oxycarbonitride, aluminium nitride, aluminium oxynitride, a mixed nitride of aluminium-silicon, a mixed oxynitride of aluminium-silicon; - wherein this barrier layer is possibly doped or alloyed with tin.
- the barrier layer is merged with at least one layer for improving light transmission forming the coating for improving light transmission.
- At least one of these two additional layers is merged with at least one layer for improving light transmission forming the coating for improving light transmission.
- the translucent conductive substrate according to the invention is such that the electrode partly forming it comprises a thin layer for homogenizing the surface electrical properties located, which, in relation to the scattering layer, is located at the top of the multilayer stacking structure forming said electrode.
- the main function of the thin layer for homogenizing the su rface electrica l properties is to allow a un iform transfer of charge to be obtained over the entire surface of the electrode. This uniform transfer is indicated by a balanced flux of emitted light at every point of the surface. It also enables the service life of the OLED to be increased, since this transfer is the same at each point, thus eliminating any possible hot spots.
- the homogenisation layer has a geometric thickness of at least 0.5 nm, preferably of at least 1.0 nm.
- the homogenisation layer has a geometric thickness of at most 6.0 n m, preferably at most 2.5 n m, more preferred at most 2.0 nm . It is more preferred that the homogenisation layer is equal to 1.5 nm. Therefore, the geometric thickness of the homogenisation layer is advantageously comprised within the range of two of the preceding values, preferably within the range from 0.5 nm to 6.0 nm, more preferably from 1.0 nm to 2.5 nm, the most preferably from 1.0 nm to 2.0 nm.
- the homogenisation layer comprises at least one layer composed of at least one inorganic material selected from a metal, a nitride, an oxide, a carbide, an oxynitride, an oxycarbide, a carbonitride, an oxycarbonitride.
- the inorganic material of the homogenisation layer is composed of a single metal or a mixture of metals.
- the generic term "mixture of meta ls" denotes the combinations of at least two metals in the form of alloy or doping of at least one metal by at least one other metal.
- the homogenisation layer is composed of at least one element selected from Li, Na, K, Be, Mg, Ca, Ba, Sc, Y, Ti, Zr, Hf, Ce, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, B, Al, Ga, In, TI, C, Si, Ge, Sn, Pb.
- the metal and/or mixtu re of metals comprises at least one element selected from Li, Na, K, Mg, Ca, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Co, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Si, C. It is more preferred that the metal or the mixture of metals comprises at least one element selected from C, Ti, Zr, Hf, V, Nb, Ta, Ni, Cr, Al, Zn .
- the mixture of metals preferably comprises Ni-Cr and/or Zn doped with Al .
- the advantage provided by this particular example is that it allows a better possible compromise to be reached between the electrical properties resulting from the effect of the layer for homogenizing surface electrical properties, on the one hand, and the optical properties obtained as a result of the improvement coating, on the other.
- the use of a homogenisation layer that has the lowest possible thickness is a basic requirement. In fact, the influence of this layer on the amount of light emitted by the OLED is a ll the less when its th ickness is low. Therefore, if metallic, this homogenisation layer is distinguished from the conduction layer by its lower thickness, since this thickness is insufficient to assure conductivity. It is therefore preferred that the homogenisation layer has a geometric thickness of 5.0 nm at most, if it is metallic, i.e. composed of a single metal or a mixture of metals.
- the inorganic material of the homogenisation layer is present in the form of at least one chemical compound selected from carbides, carbonitrides, oxynitrides, oxycarbides, oxycarbonitrides as well as mixtures of at least two thereof.
- the oxynitrides, oxycarbides, oxycarbonitrides of the homogenisation layer can be in non-stoichiometric, preferably under-stoichiometric, form in relation to oxygen .
- the carbides are carbides of at least one element selected from Be, Mg, Ca, Ba, Sc, Y, Ti, Zr, Hf, Ce, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Co, Rh, Ir, Ni, Pd, Pt, Cu, Au, Zn, Cd, B, Al, Si, Ge, Sn, Pb, preferably at least one element selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Co, Ni, Pd, Pt, Cu, Au, Zn, Cd, Al, Si, more preferred at least one element selected from Ti, Zr, Hf, V, Nb, Ta, Ni, Cr, Zn, Al.
- the carbonitrides are carbonitrides of at least one element selected from Be, Sc, Y, Ti, Zr, Hf, V, Nb, Cr, Mo, W, Fe, Co, Zn, B, Al, Si, preferably of at least one element selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Co, Zn, Al, Si, more preferred of at least one element selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Zn, Al.
- the oxynitrides are oxynitrides of at least one element selected from Be, Mg, Ca, Sr, Sc, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Co, Rh, Ir, Ni, Cu, Au, Zn, B, Al, Ga, In, Si, Ge, preferably of at least one element selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Co, Ni, Cu, Au, Zn, Al, Si, more preferred of at least one element selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Zn, Al.
- the oxycarbides are oxycarbides of at least one element selected from Be, Mg, Ca, Sr, Sc, Y, Ti, Zr, Hf, V, Nb, Cr, Mo, W, Mn, Fe, Ni, Zn, Si, Ge, preferably of at least one element selected from Ti, Zr, Hf, V, Nb, Cr, Mo, W, Mn, Ni, Zn, Al, Si, more preferred of at least one element selected from Ti, Zr, Hf, V, Nb, Cr, Zn, Al.
- the oxycarbonitrides are oxycarbonitrides of at least one element selected from Be, Ti, Zr, Hf, V, Nb, Cr, Mo, W, Mn, Zn, B, Al, Si, Ge, preferably of at least one element selected from Ti, Zr, Hf, V, Nb, Cr, Mo, W, Mn, Zn, Al, Sn, more preferred of at least one element selected from Ti, Zr, Hf, V, N b, Cr, Zn , Al .
- the ca rbides, ca rbon itrides, oxyn itrides, oxyca rbides, oxycarbonitrides of the layer for homogenizing surface electrical properties possibly comprise at least one doping element.
- the th i n homogenisation layer comprises at least one oxyn itride composed of at least one element selected from Ti, Zr, Cr, Mo, W, Mn, Co, Ni, Cu, Au, Zn, Al, Si. More preferred the thin layer for homogenizing surface electrical properties comprises at least one oxynitride selected from Ti oxynitride, Zr oxynitride, Ni oxynitride, NiCr oxynitride.
- the inorganic material of the homogenisation layer is present in the form of at least one metal nitride of at least one element selected from Be, Mg, Ca, Sr, Ba, Sc, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, In, Si, Ge, Sn .
- at least one metal nitride of at least one element selected from Be, Mg, Ca, Sr, Ba, Sc, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, In, Si, Ge, Sn .
- the homogenisation layer comprises at least one nitride of a n element selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Co, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Si.
- the nitride comprises at least one element selected from Ti, Zr, Hf, V, Nb, Ta, Ni, Cr, Al, Zn.
- the thin layer for homogenizing surface electrical properties comprises at least Ti nitride, Zr nitride, Ni nitride, NiCr nitride.
- the inorganic material of the homogenisation layer is present in the form of at least one metal oxide of at least one element selected from Be, Mg, Ca, Sr, Ba, Sc, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, In, Si, Ge, Sn, Pb.
- the homogenisation layer comprises at least one oxide of a n element selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Co, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, In, Si, Sn. More preferred, the oxide comprises at least one element selected from Ti, Zr, Hf, V, Nb, Ta, Ni, Cu, Cr, Al, In, Sn, Zn.
- the oxide of the homogenisation layer can be a under-stoichiometric oxide in oxygen .
- the oxide possibly comprises at least one doping element.
- the doping element is selected from at least one of the element chosen from Al, Ga, In, Sn, Sb, F, Ag.
- the th in layer for homogenizing surface electrical properties comprises at least Ti oxide and/or Zr oxide a nd/or Ni oxide a nd/or N iCr oxide a nd/or ITO a nd/or doped Cu oxide, wherein the doping agent is Ag, and/or doped Sn oxide, wherein the doping agent is at least one element selected from F and Sb, and/or doped Zn oxide, wherein the doping agent is at least one element selected from Al, Ga, Sn, Ti.
- the translucent conductive substrate according to the invention is such that the electrode partly forming it comprises at least one additional insertion layer located between the metal conduction layer and the thin homogenisation layer.
- the layer inserted between the metal conduction layer and the homogenisation layer comprises at least one layer composed of at least one dielectric com pou nd a nd/or at least one electrica l ly cond uctive compou nd .
- the insertion layer comprises at least one layer composed of at least one conductive compound. The function of this insertion layer is to form a part of an optical cavity that ena bles the meta l cond uction layer to become tra nspa rent.
- dielectric compound is understood to mean at least one compound selected from the following : the oxides of at least one element selected from Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Zn, Al, Ga, In, Si, Ge, Sn, Sb, Bi as well as the mixed oxide of at least two thereof: the nitrides of at least one element selected from boron, aluminium, silicon, germanium as well as a mixed nitride of at least two thereof; silicon oxynitride, aluminium oxynitride, mixed oxynitride of silicon-aluminum; a silicon oxycarbide.
- the d ielectric compou nd prefera bly comprises a n yttriu m oxide, a titanium oxide, a zirconium oxide, a hafnium oxide, a niobium oxide, a tantalum oxide, a zinc oxide, a tin oxide, an aluminium oxide, an alu minium nitride, a silicon nitride and/or a silicon oxycarbide.
- u nderstood to relate to a compou nd chosen from the following : under-stoichiometric oxides in oxygen and doped oxides of at least one element selected from Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Zn, Al, Ga, In, Si, Ge, Sn, Sb, Bi as well as a mixed under-stoichiometric oxides in oxygen, a mixed doped oxides of at least two thereof; - doped nitrides of at least one element selected from boron, aluminium, silicon, germanium as well as a mixed doped nitride of at least two thereof; doped Si oxycarbide; the doping agents preferably comprise at least one of the elements chosen from Al, Ga, In, Sn, P, Sb, F. In the case of silicon oxynitride the doping agents comprise B, Al and/or Ga.
- the cond uctive compou nd prefera bly comprises at least ITO a nd/or doped Sn oxide, wherein the doping agent is at least one element chosen from F and Sb, and/or doped Zn oxide, wherein the doping agent is at least one element chosen from Al, Ga, Sn , Ti .
- the inorgan ic chemica l compound comprises at least ZnO x (where x ⁇ 1) and/or Zn x Sn y O z (where x + y > 3 and z ⁇ 6).
- Zn x Sn y O z prefera bly com prises at most 95% by weig ht of zi nc, a nd the percentage by weight of zinc is expressed in relation to the total weight of the metals present in the layer.
- Equation E org A - E in surprisingly allows the geometric thickness of the first organic layer of the organic light-emitting device to be used to optimise the optical parameters (geometric thickness and refractive index) of the insertion layer a nd therefore to optimise the amou nt of light transmitted while retain ing a th ickness of the insertion layer that is compatible with the electrical properties that enable high ignition voltages, i.e. for a first luminance maximum, to be avoided.
- Equation E org C - E in surprising ly allows the geometric thickness of the first organic layer of the organic light-emitting device to be used to optimise the optical parameters (geometric thickness and refractive index) of the insertion layer and therefore to optimise the amount of light transmitted while reta i n i ng a th ickness of the i nsertion layer that is compati ble with the electrica l properties that enable high ignition voltages, i.e. for a second luminance maximum, to be avoided.
- the translucent conductive substrate according to the invention is such that the metal conduction layer of the electrode comprises at least one sacrificial layer on at least one of its faces.
- Sacrificial layer is understood to mean a layer that can be fully or partially oxidised or nitrided . This layer allows deterioration of the metal conduction layer, in particular as a result of oxidation or nitridation, to be avoided .
- the presence of this sacrificial layer is compatible with the action of a crysta llisation layer.
- the sacrificial layer comprises at least one compound selected from metals, nitrides, oxides, under- stoichiometric metal oxides in oxygen.
- the metals, nitrides, oxides, under- stoichiometric metal oxides in oxygen comprise at least one element selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Co, Ni, Cu, Zn, Al.
- the sacrificial layer preferably comprises at least Ti, Zr, Ni, Zn, Al .
- the sacrificial layer comprises at least Ti, TiO x (where x ⁇ 2), NiCr, NiCrO x , TiZrO x (TiZrO x indicates a titanium oxide layer with 50% by weight of zirconium oxide), ZnAIO x (ZnAIO x indicates a zinc oxide layer with 2 to 5% by weig ht of a l u m i n i u m oxid e) .
- the th ickness of the sacrificia l layer has a geometric thickness of at least 0.5 nm.
- the thickness of the sacrificial layer comprises a thickness of at most 6.0 nm, preferably of at most 5.0 nm. It is more preferred if the thickness is equal to 2.5 nm. Therefore, the geometric thickness of the sacrificial layer is advantageously comprised within the range of two of the preceding values, preferably within the range from 0.5 to 6.0 nm, more preferably from 0.5 to 5 nm. According to a preferred em bod i ment, a sacrificia l layer is deposited on the face of the meta l conduction layer furthest removed in relation to the support.
- the translucent conductive substrate according to the invention is such that the stacking structure comprising the support and the scattering layer on which the electrode is deposited, comprises at least one functional coating on the face opposite the face, on which the electrode is deposited.
- Th is coating comprises at least one coating selected from an antireflective layer or multilayer stacking structure, a diffusion layer, a non-fogging or anti-soiling layer, an optical filter, in particular a titanium oxide layer, a selective absorbent layer, a micro- lens system such as those described in the article by Lin and Coll ., for example, in Optics Express, 2008, vol. 16, no. 15, pp.
- the translucent conductive substrate according to the invention essentially has the following structure, starting from a clear or extra-clear glass support:
- T ME T ME _o + [B * sin(n*T D i/T D i_o)]/(n S upport) 3
- T M E_O B and T D i_ 0 are such that T M E_O has a value in the ra nge of 10.0 to 23.0 nm, preferably 10.0 to 22.5 nm, more preferred 11.5 to 22.5 nm, B has a value in the range of 11.5 to 15.0 and T Di 0 has a value in the range of 24.8 * n D i to 27.3 * n Di nm.
- T M E_O B and T D i_ 0 are such that T M E_o has a value in the range of 10.0 to 23.0 nm, preferably 10.0 to 22.5 nm, more preferred 11.5 to 22.5 nm, B has a value in the range of 12.0 to 15.0 and T Di 0 has a value in the range of 24.8 * n Di to 27.3 * n Di nm, a sacrificial layer: geometric th ickness 1.0-3.0 nm made of Ti or TiO x (x ⁇ 2), an insertion layer: geometric th ickness 3.0-20.0 n m made of Zn x Sn y O z (where where x + y > 3 and z ⁇ 6), a homogenisation layer: geometric thickness 0.5-3.0 nm made of X, X nitride, X oxynitride where X: Ti, Zr, Hf, V, Nb, Ta, Ni, P
- a scattering layer formed over the transparent support and comprising a glass which contains a base material having a first refractive index for at least one wavelength of light to be transmitted and a plurality of scattering materials dispersed in the base material and having a second refractive index different from that of the base material, said scattering layer having a geometrical thickness in the range of 10 ⁇ to 60 ⁇ ,
- the geometric thickness of the coating from improving light transmission is advantageously comprised within the range of two of the preceding values, preferably within the range from 50.0 nm to 100.0 nm, more preferably from 60.0 nm to 90.0 nm, the most preferably from 70.0 nm to 80.0 nm.
- the geometric thickness of the metal conduction layer is at least equal to 6.0 nm, preferably at least equal to 8.0 nm, more preferred at least equal to 10.0 nm and at most equal to 22.0 n m, prefera bly at most eq ual to 20.0 n m, more preferred at most equa l to 18.0 nm, therefore the geometric thickness of the metal conduction layer is advantageously comprised with in the range of two of the preced ing va lues, preferably within the range from 6.0 nm to 22.0 nm, more preferably from 8.0 nm to 20.0 nm, the most preferably from 10.0 nm to 18.0 nm.
- a sacrificial layer geometric thickness 1.0-3.0 nm made of Ti or TiO x (x ⁇ 2)
- - an insertion layer geometric thickness 3.0-20.0 nm made of Zn x Sn y O z (where where x + y > 3 and z ⁇ 6)
- a homogenisation layer geometric thickness 0.5-3.0 nm made of X, X nitride, X oxynitride where X: Ti, Zr, Hf, V, Nb, Ta, Ni, Pd, Cr, Mo, Al, Zn, Ni-Cr or Zn doped with Al.
- the translucent conductive substrate according to the invention essentially has the following structure, starting from a clear or extra-clear glass support:
- a scattering layer formed over the transparent support and comprising a glass which contains a base material having a first refractive index for at least one wavelength of light to be transmitted and a plurality of scattering materials dispersed in the base material and having a second refractive index different from that of the base materia l, sa id scattering layer having a geometrica l thickness in the range of 10 ⁇ to 60 ⁇ ,
- the geometric thickness of the metal conduction layer is at least equal to 16.0 nm, preferably at least equal to 18.0 n m, more preferred at least equal to 20.0 n m and at most eq ual to 29.0 n m, preferably at most eq ual to 27.0 n m and most preferred at most equal to 25.0 nm, therefore, the geometric thickness of the metal conduction layer is advantageously comprised with in the range of two of the preceding values, preferably within the range from 16.0 nm to 29.0 nm, more preferably from 18.0 nm to 27.0 nm, the most preferably from 20.0 nm to 25.0 nm.
- a sacrificial layer geometric thickness 1.0-3.0 nm made of Ti or TiO x (x ⁇ 2)
- - an insertion layer geometric thickness 3.0-20.0 nm made of Zn x Sn y O z (where where x + y > 3 and z ⁇ 6)
- a homogenisation layer geometric thickness 0.5-3.0 nm made of X, X nitride, X oxynitride where X: Ti, Zr, Hf, V, Nb, Ta, Ni, Pd, Cr, Mo, Al, Zn, Ni-Cr or Zn doped with Al.
- the embodiments of the translucent conductive substrate are not limited to the embodiments outlined a bove, but can equally be formed by combin ing two or more thereof.
- the second subject of the invention relates to a method for the manufacture of the translucent conductive substrate according to the invention .
- Th is substrate comprises a support, a scattering layer and an electrode.
- the process for the manufacture of the translucent conductive su bstrate accord ing to the invention is a process, in which :
- the scattering layer is made as follow: oxide, phosphate, metaphosphate, carbonate, nitrate, hydroxide or other materials are used as starting materials to make the scattering layer. First, they are scaled to become the predetermined amount, and the collected materials are mixed. Then, the mixed materials are dissolved at a temperature of from 950 to 1500°C by using a platinum crucible and so on. Then, the dissolved materials are poured into a mould or the gap of twin roll. The poured materials are rapidly cooled in order to have a glass of the invention. There is a possibility of cooling gradually to remove the distortion, too.
- the invention is used in the form of glass frit which was prepared by the method above.
- the glass is crushed by using a mortar, ball mill, jet mill grinding due and so on or is classified if necessary to get the glass frit.
- Mass average particle size of glass frit is typically 0.5 to 10 microns.
- the surface of the glass frit can be reformed by a surfactant or a silane coupling agent. If necessary, it is also possible to mix the solvent, the binder, etc. and this glass frit.
- the mixed glass frit is coated on a transparent support and is fired at the temperature higher than about 60 °C in comparison with the glass transition temperature of the glass frit to cause the glass frit soften. After being cooled to room temperature, a transparent support with a scattering layer is obtained.
- ether type solvents butyl carbitol (BC), butyl carbitol acetate (BCA), diethylene glycol di-n-butyl ether, dipropylene glycol dibutyl ether, tripropylene glycol butyl ether and butyl cellulosolve acetate
- alcohol type solvents ⁇ - terpineol, pine oil and Dowanol
- ester type solvent 2,2,4 - trimethyl - 1,3 - pentanediol monoisobutyrate
- phtalic acid ester type solvents DBP (dibutyl phthalate), DMP (dimethyl phthalate) and DOP (dioctyl phthalate)
- Mainly used are - -terpineol and 2,2,4 - trimethyl - 1,3 - pentanediol monoisobutyrate.
- DBP dibutyl phthalate
- DMP dimethyl phthalate
- DOP dioctyl phthalate
- a binder ethyl cellulose, nitrocellulose, an acrylic resin, vinyl acetate resin, a butyral resin, a melamine resin, an alkyd resin, a rosin resin or the like. Used as base resins are ethyl cellulose and nitrocellulose.
- a butyral resin, a melamine resin, an alkyd resin and a rosin resin are used as additives for improving coated film strength.
- any ingredients other than binder or solvent may be introduced.
- the binder before the glass frit is soften, it is desirable to contain the process of firing at a temperature that is lower than the glass transition temperature and evaporating the binder.
- the inventors have surprisingly found that the preferred firing temperature value is comprised in the range from 530 °C to 580 °C.
- the electrode is made by deposition on the scattering layer of at least one layer of the stacking structure constituting said electrode thanks to a method selected from cathodic sputtering techniques, possibly using a magnetic field, deposition techniques using plasma, CVD (chemical vapour deposition) and/or PVD (physical vapour deposition) techniques.
- the deposition method is preferably conducted under vacuum.
- under vacuum denotes a pressure lower than or equal to 2.0 Pa. More preferred, the process under vacuum is a magnetron sputtering technique.
- the process for the manufacture of the translucent conductive substrate comprises continuous processes, in which every layer forming the electrode is deposited immediately after the layer underlying it in the multilayer stacking structure (e.g.
- the manufacturing process also comprises discontinuous processes in which a time interval (e.g. in the form of storage) separates the deposition of one layer and the layer underlying it in the stacking structure forming the electrode.
- a time interval e.g. in the form of storage
- the method for the manufacture of the translucent conductive su bstrate accord i ng to the i nvention is such that it is conducted in three phases as follows:
- the process for the manufacture of the translucent conductive substrate according to the invention is such that it is conducted in three phases as follows:
- the organic portion of the OLED is deposited immediately after deposition of the homogenisation layer or the metal conduction layer, i.e. without the homogenisation layer or the metal conduction layer being exposed before deposition of the organic portion of the OLED.
- the layer for homogenizing the su rface electrica l properties based on oxides and/or oxynitrides ca n be obtained by direct deposition.
- the homogenisation layer based on oxides and/or oxynitrides can be obtained by oxidation of the meta ls a nd/or the correspond i ng n itrides (e.g . Ti is oxid ised i n Ti oxide, Ti n itride is oxid ised i n Ti oxynitride). This oxidation can occur directly or a long time after deposition of the homogenisation layer.
- the oxidation can be natural (e.g. through interaction with an oxidising compound present during the manufacturing process or during storage of the electrode before complete manufacture of the OLED) or can result from a post- treatment operation (e.g. treatment in ozone under ultraviolet light).
- the process comprises a n additional step of structuring the surface of the electrode.
- Structuring of the electrode is different from structuring of the support.
- This additional step consists of shaping the su rface a nd/or decorating the su rface of the electrode.
- the process of shaping the surface of the electrode comprises at least engraving by laser or etching .
- the process of decorating the surface comprises at least a masking operation .
- Maski ng is the operation in which a portion at least of the surface of the electrode is covered with a protective coating as part of a post-treatment process, e.g . etch ing of the uncoated parts.
- the translucent conductive substrate according to the present invention is incorporated into an OLED that emits light.
- the organic light- em itti ng device com prises a n OLED system a bove the su bstrate accord i ng to the invention for the purpose of emitting a quasi-white light.
- quadri-white light is understood to mean a light in which, with a perpendicular radiation to the surface of the substrate, the chromatic coordinates at 0° are contained in one of the eight chromaticity quadrilaterals, with contours of the quadrilaterals included .
- These quadrilaterals are defined in pages 10 to 12 of standard ANSI_NEMA_ANSLG C78.377-2008. These quadrilaterals are shown in Figure Al, part 1 entitled “Graphical representation of the chromaticity specification of SSL products in Table 1, on the CIE (x,y) chromaticity diagram".
- the organic light-emitting device is integrated into a glazing, a double glazing or a laminated glazing. It is also possible to integrate several organic light-emitting devices, preferably a large nu mber of organic light-emitting devices.
- the organic light-emitting device is enclosed in at least one encapsulation material made of glass and/or plastic.
- the different embodiments of the organic light-emitting devices can be combined.
- the different organic light-emitting devices have an extensive field of application.
- the invention concerns in particular possible uses of these organic light-emitting devices in the formation of one or more lu minous su rfaces.
- the term "lu minous su rface" includes, for exa mple, lighting tiles, lu minous panels, lu minous pa rtitions, work su rfaces, g lasshouses, flash l ig hts, screen bases, d rawer bases, luminous roofs, touch screens, lamps, camera flash systems, luminous bases for display, security lights and shelves.
- the translucent conductive substrate according to the invention will now be illustrated on the basis of the following figures.
- the figures show in a non-restrictive manner some substrate structu res. These figures are purely for illustration purposes and do not constitute a representation of structures to scale.
- Figure 1 shows a cross-sectional view of a translucent conductive substrate according to the invention, wherein the substrate comprises a su pport, a scattering layer and an electrode formed from a stacking structu re consisting of a minimum number of layers.
- Figure 2 shows a cross-sectional view of a translucent conductive substrate according to the invention in a second embodiment.
- Figure 3 shows a cross-sectional view of a translucent conductive substrate according to the invention, wherein the substrate comprises a support having a barrier layer, a scattering layer and an electrode formed from a stacking structure consisting of a minimum number of layers and with a different function.
- Figure 4 shows a cross-sectional view of the translucent conductive substrate according to the invention in a preferred embodiment.
- Figure 5 shows the evolution of the luminance of an organic light- emitting device emitting a quasi-white light and comprising a substrate without the scattering layer and having a transparent su pport with a refractive index of 1.4 at a wavelength equal to 550 nm as a function of the geometric thickness of the coating for improving the light transmission with a refractive index of 2.3 at a wavelength of 550 nm and of the geometric thickness of a metal conduction layer of Ag.
- Figure 6 shows the evolution of the luminance of an organic light- emitting device emitting a quasi-white light and comprising a substrate without the scattering layer and having a transparent su pport with a refractive index of 1.5 at a wavelength equal to 550 nm as a function of the geometric thickness of the coating for improving the light transmission with a refractive index of 2.3 at a wavelength of 550 nm and of the geometric thickness of a metal conduction layer of Ag.
- Figure 7 shows the evolution of the luminance of an organic light- emitting device emitting a quasi-white light and comprising a substrate without the scattering layer and having a transparent su pport with a refractive index of 1.6 at a wavelength equal to 550 nm as a function of the geometric thickness of the coating for improving the light transmission with a refractive index of 2.3 at a wavelength of 550 nm and of the geometric thickness of a metal conduction layer of Ag.
- Figure 8 shows the evolution of the luminance of an organic light- emitting device emitting a quasi-white light and comprising a substrate without the scattering layer and having a transparent su pport with a refractive index of 1.8 at a wavelength equal to 550 nm as a function of the geometric thickness of the coating for improving the light transmission with a refractive index of 2.3 at a wavelength of 550 nm and of the geometric thickness of a metal conduction layer of Ag.
- Figure 9 shows the evolution of the luminance of an organic light- emitting device emitting a quasi-white light and comprising a substrate without the scattering layer and having a transparent support with a refractive index of 2.0 at a wavelength equal to 550 nm as a function of the geometric thickness of the coating for improving the light transmission with a refractive index of 2.3 at a wavelength of 550 nm and of the geometric thickness of a metal conduction layer of Ag.
- Figure 10 shows the photoluminescence as a function of the wavelength spectrum of a monochromic radiation, the main wavelength of which lies in the red light range.
- Figure 11 shows the photoluminescence as a function of the wavelength spectrum of a monochromic radiation, the main wavelength of which lies in the green light range.
- Figure 12 shows the photoluminescence as a function of the wavelength spectrum of a monochromic radiation, the main wavelength of which lies in the blue light range.
- Figure 13 shows the evolution of the luminance of the organic light- emitting device comprisi ng a su bstrate without the scattering layer a nd havi ng a transparent support, as a function of the geometric thickness and the refractive index of the layer for improving light transmission of the electrode according to the invention for a red light, wherein a metal conduction layer of Ag has a geometric thickness equal to 12.5 nm and a support has a refractive index of 1.5.
- Figure 14 shows the evolution of the luminance of the organic light- emitting device com prisi ng a su bstrate without the scattering layer a nd having a transparent support, as a function of the geometric thickness and the refractive index of the layer for improving light transmission of the electrode according to the invention for a green lig ht, wherein a meta l conduction layer of Ag has a geometric th ickness equal to 12.5 nm and a support has a refractive index of 1.5.
- Figure 15 shows the evolution of the luminance of the organic light- emitting device comprisi ng a su bstrate without the scattering layer a nd havi ng a transparent support, as a function of the geometric thickness and the refractive index of the layer for improving light transmission of the electrode according to the invention for a blue light, wherein a metal conduction layer of Ag has a geometric thickness equal to 12.5 nm and a support has a refractive index of 1.5.
- Figure 16 shows the evolution of the luminance of the organic light- emitting device comprising a substrate without the scatteri ng layer a nd having a transparent support, as a function of the geometric thickness and the refractive index of the layer for improving transmission of the electrode according to the invention for a red light, wherein a metal conduction layer of Ag has a geometric thickness equal to 12.5 nm and a support has a refractive index of 2.0.
- Figure 17 shows the evolution of the luminance of the organic light- emitting device comprisi ng a su bstrate without the scattering layer a nd havi ng a transparent support, as a function of the geometric thickness and the refractive index of the layer for improving light transmission of the electrode according to the invention for a green lig ht, wherein a meta l conduction layer of Ag has a geometric th ickness equal to 12.5 nm and a support has a refractive index of 2.0.
- Figure 18 shows the evolution of the luminance of the organic light- emitting device comprisi ng a su bstrate without the scattering layer a nd havi ng a transparent support, as a function of the geometric thickness and the refractive index of the layer for improving light transmission of the electrode according to the invention for a blue light, wherein a metal conduction layer of Ag has a geometric thickness equal to 12.5 nm and a support has a refractive index of 2.0.
- Figure 19 shows the evolution of the simulated reflection, expressed in D65 at 2° in accordance with European standard EN 410, of a substrate without the scattering layer and having a transparent support, said support having a refractive index equal to 1.5 at a wavelength equal to 550 nm, as a fu nction of the geometric thickness of the coating for improving light transmission and of the geometric thickness of the metal conduction layer of Ag, wherein above the conduction layer the substrate also comprises a sacrificial layer of TiO x that has a geometric thickness equal to 3.0 nm and an insertion layer of Zn x Sn y O z (where x + y > 3 and z ⁇ 6) that has a geometric th ickness eq ua l to 14.7 n m, wherei n the insertion layer is coated with an orga n ic medium with a refractive index equal to 1.7 at a wavelength of 550 nm.
- Figure 20 shows the evolution of the luminance of the organic light- emitting device incorporating a substrate without the scattering layer and having a transparent support, said support having a refractive index of 1.5 at a wavelength of 550 nm and a metal conduction layer with a geometric thickness of 12.5 n m as a function of the geometric thicknesses of the insertion layer (E in ) and the first organic layer of the electrode for a green light.
- Figure 21 shows a measurement device for measuring the light emitting luminance and the angular dependency light-emitting colour.
- Figure 1 shows an example of stacking structu re forming a translucent conductive substrate according to the invention.
- the translucent conductive substrate (1) has the following structure, starting from the transparent support (10):
- an electrode (12) constituted by : ⁇ a coating for improving light transmission (120) comprising a layer for improving light transmission (1201),
- Figure 2 shows an alternative example of the translucent conductive substrate according to the invention .
- Th is comprises, in addition to the layers already present in Figure 1 constituting the electrode (12), an insertion layer (123) and a layer for homogenizing surface electrical properties (124).
- the translucent conductive substrate has the following structure, starting from the support (10):
- Figure 3 shows another translucent substrate according to the invention.
- This comprises, in addition to the layers already present in Figure 2 constituting the electrode, an additional barrier layer (1200) and an additional crystallisation layer (1202) belonging to the coating for improving light transmission (120), two sacrificial layers (121a, 121b).
- the translucent conductive substrate according to the invention comprises also a barrier layer (9b) located between the support (10) and the scattering layer (11) and a functional coating (9a) on the second face of the transparent support (10).
- the translucent conductive substrate has the following structure, starting from the second face of the support (10):
- an electrode (12) constituted by : ⁇ a coating for improving light transmission (120) comprising : o a barrier layer (1200) o a layer for improving light transmission (1201) o a crystallisation layer (1202)
- Figure 4 shows another example of a translucent substrate according to the invention.
- the substrate has the following structure, starting from the support (10):
- a coating for improving light transmission comprising : o a layer for improving light transmission (1201) o a crystallisation layer (1202)
- Figures 5, 6, 7, 8 and 9 show the evolution of the l u m ina nce of a n organic light-emitting device emitting a quasi-white light as a function of the geometric thickness of the coating for improving the l ight transmission (Dl ) with a refractive index of 2.3 (n Di ) at a wavelength of 550 nm, and of the geometric thickness of a metal conduction layer of Ag and comprising a support with a refractive index equal to 1.4, 1.5, 1.6, 1.8 and 2.0 respectively at a wavelength equal to 550 nm.
- the structure of the organic light-emitting device comprises the following stacking structure:
- the organic portion of the organic light-emitting device is such that it has the following structure: o a hole transporting layer, HTL, having a geometric thickness equal to 25.0 nm, o an electron blocking layer, EBL, having a geometric thickness equal to 10.0 nm, o an emissive layer emitting a Gaussian spectrum of white light corresponding to illuminant A and having a geometric thickness equal to 16.0 nm, o a hole blocking layer, HBL, having a geometric thickness equal to 10.0 nm, o an electron transporting layer, ETL, having a geometric thickness equal to 43.0 nm. o a counter-electrode made of Al having a thickness equal to 100.0 nm.
- T ME T ME _o + [B * sin (n*T D i/T D i_o)]/(n S upport) 3
- T M E_O B and T D i_ 0 are constants with T M E_O having a value in the range of 10.0 to 25.0 nm, B having a value in the range of 10.0 to 16.5 nm and T Di 0 having a value in the range of 23.9 * n Di to 28.3 * n Di nm, with n Di representing the refractive index of the coating for improving the light transmission at a wavelength of 550 nm and n SU pp 0rt represents the refractive index of the support at a wavelength of 550 nm.
- the luminance was calculated using the program SETFOS, version 3 (Semiconductive Emissive Thin Film Optics Simulator) from Fluxim. This luminance is expressed as arbitrary unit.
- the inventors have found surprisingly the area selected is not only valid for an organic device emitting quasi-wh ite lig ht but a lso for a ny type of colour emitted (e.g. red, green, blue).
- a hig h refractive index is understood to be a refractive index at least equal to 1.4, preferably at least equal to 1.5, more preferred at least equal to 1.6, most preferred at least equal to 1.7.
- Figures 10 to 19, more particularly figures 13 to 19, relate to an example of a substrate without scattering layer that corresponds to a conduction layer of Ag having a geometric thickness equal to 12.5 nm.
- the substrate without scattering layer is incorporated into an OLED emitting a red, green or blue colour.
- the structure of the organic light-emitting device comprises the following stacking structure: ⁇ support (10) having a geometric thickness equal to 100.0 nm
- electrode (12) o coating for improving the light transmission (120), o metal conduction layer made of Ag (122),
- the organic portion of the organic light-emitting device is such that it has the following structure: o a hole transporting layer, HTL, having a geometric thickness equal to 25.0 nm, o an electron blocking layer, EBL, having a geometric thickness equal to 10.0 nm, o an emissive layer causing emission of a spectrum of red, green or blue light, of which the (x, y) chromatic coordinates are respectively equal to coordinates (0.63, 0.36), (0.24, 0.68) or (0.13, 0.31) in the CIE 1931 colorimetric diagram, according to which the device is provided for the emission of red, green or blue light, and having a geometric thickness equal to 16.0 nm, o a hole blocking layer, HBL, having a geometric thickness equal to
- ETL electron transporting layer
- o an electron transporting layer, ETL, having a geometric thickness equal to 43.0 nm.
- o a counter-electrode made of Al having a thickness equal to 100.0 nm.
- Figures 10, 11 and 12 respectively show the evolution of the photoluminescence as a function of the wavelength spectra of a monochromic radiation, the main wavelength of which lies in the red, green or blue light range.
- Main wavelength is understood to mean the wavelength at which the photoluminescence is at its maximum.
- the term "monochromic" is understood to mean that a single colour is perceived by the eye without this light being monochromatic as such.
- Photoluminescence is expressed in the form of the relation between the value of the photoluminescence at a wavelength divided by the value of maximum photoluminescence. Therefore, the photoluminescence is a number without unit in the range of between 0 and 1.
- Figure 10 shows that at a wavelength equal to 616 nm, the photoluminescence is at maximum in the case of monochromic radiation, the main wavelength of which lies in the red colour range.
- Figure 11 shows that at a wavelength equal to 512 nm, the photoluminescence is at maximum in the case of monochromic radiation, the main wavelength of which lies in the green colour range.
- Figure 12 shows that at a wavelength equal to 453 nm, the photoluminescence is at maximum in the case of monochromic radiation, the main wavelength of which lies in the blue colour range.
- Figures 13, 14 and 15 show the development of the luminance of the organic light-emitting device as a function of the geometric thickness (Dl) and the refractive index of the coating for improving the light transmission (n Di ) (120) of the substrate without scattering layer , respectively for a red, green and blue light colour, and for a support having a refractive index of 1.5 at a wavelength of 550 nm, wherein the geometric th ickness of a metal conduction layer of Ag is equal to 12.5 n m. Th is calculation was conducted not by taking into account a luminous radiation limited to a single wavelength, but by taking into account the real spectrum of wavelengths, as shown in Figures 10, 11 and 12.
- T ME T M E _0 + [B * Si n (n*T D i/T D i_o)]/(n S upport) 3
- T M E_O B a nd T D i_ 0 are constants with T M E_O having a va lue in the range of 10.0 to 25.0 nm, B having a value in the range of 10.0 to 16.5 nm and T Di 0 having a value in the range of 23.9 * n Di to 28.3 * n Di nm, with n Di representing the refractive index of the coating for improving the light transmission at a wavelength of 550 n m a nd n SU pp 0r
- the substrate without scattering layer having a support with a refractive index equal to 1.5 at a wavelength of 550 nm and a conduction layer of Ag with a geometric thickness equal to 12.5 nm it is evident on the basis of figures 13, 14, 15, obtained for an OLED emitting a red, green and blue lig ht respectively, that a h ig h l u mi na nce is obta i ned more pa rticu la rly when the geometric thickness of the coating for improving light transmission is at least equal to 50.0 nm, preferably at least equal to 60.0 nm, more preferred at least equal to 70.0 nm and at most equal to 110.0 nm, preferably at most equal to 100.0 nm, more preferred at most equal to 90.0 nm, most preferred at most equal to 80.0 nm.
- Figures 16, 17 and 18 show the evolution of the luminance of the organic light-emitting device as a function of the geometric thickness (Dl) and the refractive index of the coating for improving the light transmission (n Di ) (120) of the substrate without a scattering layer, respectively for a red, green and blue light colour, and for a support having a refractive index of 2.0 at a wavelength of 550 nm, wherein the geometric thickness of a metal conduction layer of Ag is equal to 12.5 nm.
- This calculation was conducted not by taking into account a luminous radiation limited to a single wavelength, but by taking into account the real spectrum of wavelengths, as shown in Figures 10, 11 and 12.
- T ME T ME _o + [B * sin (n*T D i/T D i_o)]/(n S upport) 3
- T M E_O B and T D i_ 0 are constants with T M E_O having a value in the range of 10.0 to 25.0 nm, B having a value in the range of 10.0 to 16.5 nm and T Di 0 having a value in the range of 23.9 * n Di to 28.3 * n Di nm, with n Di representing the refractive index of the coating for improving the light transmission at a wavelength of 550 nm and n pp 0rt represents the refractive index of the support at a wavelength of 550 nm.
- the luminance was calculated using the program SETFOS, version 3 (Semiconductive Emissive Thin Film Optics Simulator) from Fluxim.
- a high luminance is obtained more particularly when the geometric thickness of the coating for improving light transmission is at least equal to 40.0 nm, preferably at least equal to 50.0 nm, more preferred at least equal to 60.0 nm and at most equal to 110.0 nm, preferably at most equal to 100.0 nm, more preferred at most equal to 90.0 nm.
- the geometric thickness of the coating for improving light transmission is advantageously comprised within the range of two of the preceding values, preferably comprised within the range from 40.0 nm to 110.0 nm, more preferably from 50.0 nm to 100.0 nm, the most preferably from 60.0 nm to 90.0 nm.
- Figures 13 to 18 all show that with the same substrate structu re in the case of a fixed refractive index of the support, a more significant luminance is obtained when the refractive index of the coating for improving light transmission (110) is higher than the refractive index of the support (10), particularly when n Di > 1.2*n SU pp 0rt , more particularly when n Di > 1.3*n SU pp 0rt , most particularly when n Di > 1.5*n su ppor t.
- the refractive index of the material forming the coating (n Di ) has a value ranging from 1.5 to 2.4, preferably ranging from 2.0 to 2.4, more preferred ranging from 2.1 to 2.4, at a wavelength of 550 nm. The same observation is done with a translucent cond uctive substrate according to the invention.
- the inventors have found that the optimum thickness of the improvement coating to obtain a maximum luminance, in other words a high emission level, depends little on the wavelength spectru m of the monochromic radiation (blue, g reen or red lig ht), as demonstrated i n Fig u res 13 to 18. More su rprisi ng ly, th is optimum lies in the same range of geometric thickness of the improvement coating (120). For example, in the case of a material with a refractive index ranging from 2.0 to 2.3, the geometric thickness of the improvement coating that enables an optimum emission at different wavelengths has a value ranging from 45.0 to 95.0 nm.
- the quasi-white light is preferably obtained with a geometric thickness ranging from 60.0 to 80.0 nm, more preferred from 65.0 to 75.0 nm.
- a geometric thickness ranging from 60.0 to 80.0 nm, more preferred from 65.0 to 75.0 nm.
- the first area of selection relates to substrates, wherein the support has a refractive index equal to 1.5 at a wavelength of 550 nm and the geometric thickness of the metal conduction layer is at least equal to 6.0 nm, preferably at least equal to 8.0 n m, more preferred at least eq ua l to 10.0 n m a nd at most eq ua l to 22.0 n m, preferably at most equal to 20.0 nm, more preferred at most eq ual to 18.0 n m, the geometric thickness of the metal conduction layer is advantageously comprised within the range of two of the preceding values, preferably within the range from 6.0 nm to 22.0 nm, more preferably from 8.0 nm to 18.0 nm, the most preferably from 10.0 nm to 18.0 nm, and wherein the geometric thickness of the coating for improving light transmission is at least equal to 50.0 nm, preferably at least equal to 60.0 nm and at most equal
- This structure has the triple advantage of using a low-cost soda- lime-silica glass support, of using finer metal conduction layers (e.g . of Ag) combined with g reater th icknesses of the coating for improving light tra nsmission, a nd such th icknesses allow a better protection of the metal cond uction layer against possible contamination by the migration of alkaline substances coming from the soda-lime-silica glass support.
- finer metal conduction layers e.g . of Ag
- the second area of selection concerns substrates with a support with a refractive index value in the range of 1.4 to 1.6, wherein the geometric thickness of the metal conduction layer is at least equal to 16.0 nm, preferably at least equal to 18.0 nm, more preferred at least equal to 20.0 nm and at most equal to 29.0 nm, preferably at most equal to 27.0 nm, more preferred at most equal to 25.0 nm, the geometric thickness of the metal conduction layer is advantageously comprised within the range of two of the preceding values, preferably from 16.0 nm to 29.0 nm, more preferably from 18.0 nm to 27.0 nm, the most preferably 20.0 nm to 25.0 nm, a nd wherein the geometric thickness of the coating for improving light transmission is at least equal to 20.0 n m a nd at most eq ual to 40.0 n m .
- Th is structu re has the adva ntage of usi ng th icker metal conduction layers (e.g . of silver), the use of a th ick meta l cond uction layer enabling better conduction to be achieved.
- the inventors have su rprisingly found that the same observation is also done with the translucent conductive substrate according to the invention.
- Figure 19 shows the development of the simulated reflection, expressed in D65 at 2° in accordance with European standard EN 410, of a substrate comprising a support having a refractive index equal to 1.5 at a wavelength eq ual to 550 n m as a function of the geometric thickness of the coating for improving light transmission and of the geometric th ickness of the meta l conduction layer of Ag, wherein a bove the conduction layer the substrate also comprises a sacrificial layer of TiO x that has a geometric thickness equal to 3.0 nm and an insertion layer of Zn x Sn y O z (where x + y > 3 and z ⁇ 6) that has a geometric thickness equal to 14.7 nm, wherein the insertion layer is coated with a n orga n ic med i u m with a refractive i ndex eq ua l to 1.7 at a wavelength of 550 nm.
- FIG. 20 shows the development of the luminance of the organic light- emitting device incorporating a substrate comprising a support with a refractive index of 1.5 at a wavelength of 550 n m a nd a metal conduction layer having a geometric thickness of 12.5 nm as a function of the geometric thicknesses of the insertion layer (E in ) and the first organic layer of the electrode (E org ) for a green light.
- the translucent conductive substrate according to the invention, its mode of execution as well as the organic light-emitting device containing it will now be characterised on the basis of practical examples described and collated in the following Tables I, II, III, IV, V and VI. These exa m ples a re i n no way restrictive of the invention.
- the organic light-emitting devices that emit a green-coloured monochromic radiation whose performances are shown in Tables I, II, II, IV, VI and VI have the following organic structure, starting from the translucent conductive substrate (1):
- an upper reflective electrode composed of at least one metal.
- the metal of the upper reflective electrode consists of at least Ag.
- the metal of the upper reflective electrode consists of at least Al.
- the glass substrate is a clear soda lime glass made by AGC with a thickness of 1.60 mm.
- the scattering layer is deposited on the glass support as follow: the glass frit material was mixed so that the glass composition may become, in mol% based on oxides, 22.7 mol% of P 2 0 5 , 14.9 mol% of Bi 2 0 3 , 15.7 mol% of Nb 2 0 5 , 20.6 mol% of ZnO, 11.8 mol% of B 2 0 3 , 5.0 mol% of Li 2 0 and 9.3 mol% of W0 3 .
- the prepa red frit materia l was dissolved spending 90 min utes at 1050°C in electric furnace, and after holding for 60 minutes at 950°C, the glass flakes was obtained by a roll cast.
- the glass transition temperature of this glass is 475°C, its deformation point is 525°C, the thermal expansion coefficient is 72x lO-7(l/°C) (average value of from 50 to 300°C).
- the measurement was done at 5°C/min by the thermal expansion method by using the thermal analysis equipment (Made by the Bruker company, the brand name: TD5000SA).
- the refractive index nF at F-line (486.13n m) is 2.00
- the refractive index nd at d-line (587.56nm) is 1.98
- the refractive index nC at C-line (656.27nm) is 1.97.
- the refractive index meter (Made by Shimadzu Device corporation, the brand name: KPR-2000) is used.
- the crushed glass flakes were put through a sieve to obtain the glass frits.
- the particle size distribution of the g lass flakes is that D 50 was 2.15 ⁇ , D i0 was 0.50 ⁇ , and D 90 was 9.72 ⁇ .
- D 50 2,15um means that 50% of the particles have a particle size lower than or equal to 2.15 ⁇
- ⁇ 90 9.72 ⁇ means that 90% of the particles have a particles size lower than or equal to 9.72 ⁇ .
- the particles size is determined by TEM (Transmission Electron Microscope) pictures.
- the obtained glass frits 35g were mixed with the organic vehicle which was dissolved by - -terpineol and ethyl cellulose to obtain glass paste.
- the glass paste was uniformly printed on the glass support in the circle where the diameter was 10 mm, causing an after-firing thickness to be 14 ⁇ .
- the substrate was returned to room temperature once. The temperature rose up to 450°C by taking 45 minutes. Then, the su bstrate was held for 30 min utes at 450°C to be fired.
- the layers forming the electrode (12) of the examples of translucent conductive substrate (1) according to the invention have been deposited by magnetron sputtering onto a clear glass support (10) with a thickness of 1.60 mm.
- the deposition conditions for each of the layers are as follows:
- the Ti-based layers are deposited using a Ti target at a pressure of 0.5 Pa in an Ar atmosphere and can be partially oxidised by the subsequent Ar/0 2 plasma,
- the deposition conditions require a lower temperature which reduces the risk of an alkaline migration from the support of the scattering layer.
- Table I shows four columns with examples of translucent conductive substrates (1) not in conformity with the invention as well as the results of measurements of electrical and optical performance obtained by means of the organic light-emitting device in which these substrates are incorporated.
- the general structure of the organic light-emitting device has been described above (p. 46, I. 19 to p. 48, I. 16).
- Example I.1R is an ITO electrode.
- Example I.2R is an ITO with a scattering layer.
- the improvement coating (120) has a barrier layer (1200), which is merged with a layer for improving light transmission (1201) and this layer is covered by a crystallisation layer (1202).
- the crystallisation (1202) and insertion (123) layers are of the sa me natu re. These layers are made of Zn x Sn y O z (where x + y > 3 and z ⁇ 6), the Zn x Sn y O z preferably comprising at most 95% by weight of zinc, the percentage by weight of zinc being expressed in relation to the total weight of the metals present in the layer based on an architectural low-emission stacking structure having a cond uction layer of Ag (122).
- Insertion layer (113) Zn x Sn y O z Zn x Sn y O z /7.0
- the support (10) is a clear glass with a geometric thickness equal to 1.60
- Ta ble II shows two colu mns with exa mples of translucent conductive substrates (1) according to the invention and having different types of electrodes as well as the electrical a nd optical performance of the organ ic light-emitting device in which these are incorporated.
- the improvement coating (120) has a barrier layer (1200) which is covered by a crystallisation layer (1202).
- crysta llisation (1202) a nd insertion (123) layers are of the same natu re. These layers are made of Zn x Sn y O z (where x + y > 3 and z ⁇ 6), the Zn x Sn y O z preferably comprising at most 95% by weight of zinc, the percentage by weight of zinc being expressed in relation to the total weight of the metals present in the layer.
- Insertion layer (123) Zn x Sn y O z /7.0 Zn x Sn y O z /7.0
- Homogenisation layer (124) Ti nitride / 1.5 Ti nitride / 1.5
- the support (10) is a clear glass with a geometric thickness equal to 1.60
- OCE out-cou pl ing coefficient efficiency
- the OCE were obtained by dividing the luminance values obtained by the value of the luminance measured for example I. IR.
- the optical measurement were performed thanks to a multi-channel spectroscope (trade name: C10027) manufactured by Hamamatsu Photonics K.K..
- a multi-channel spectroscope (trade name: C10027) manufactured by Hamamatsu Photonics K.K.
- the angle between a normal line direction of the element and a d irection extending from the element to the spectroscope was defined as the measurement angle ⁇ (fig . 21).
- the inventors found that small variation in the structure of the mu ltilayered translucent conductive su bstrate have a significant influence on the OCE. This effect on the OCE is found despite the fact that the refractive index of the first layer of the multilayer electrode is comparable to that of the scattering layer.
- the comparison of example I.3R and II.5 but also of examples I.4R and II.6 shows the effect of the scattering layer on the OCE.
- the incorporation of the scattering layer leads to an increase of 10% of the OCE.
- the incorporation of the scattering layer leads to an increase of the OCE of 58%.
- the inventors have surprisingly found as shows by the comparison of example I.3R and II.6 that an increase of around 90% of the OCE is obtained when a translucent conductive substrate according to the invention is used .
- the comparison of the OCE obtained shows a synergetic effect of the scattering layer and the optimized electrode on the OCE. If the effect would be simply cumulative an increase of 30% of the OCE would be obtained : 10% thanks to the scattering layer used and 20% thanks to the optimized electrode.
- the comparison of the OCE clearly shows that the amount of light emitted by the example II.6 is 90% higher than the amount of light emitted by the example I.1R which represents a conventional substrate for OLED (ITO electrode on glass)
- Ax(withoutscatteringlayer) x ⁇ ° ° - -X ⁇ n 70 °
- - ⁇ max represents the highest x value measured between 0° and 70°; represents the lowest x value measured between 0° and 70°
- ⁇ max represents the highest y value measured between 0° and 70°
- y ⁇ a represents the lowest y value measured between 0° and 70°
- ⁇ max represents the highest x value measured between 0° and 70°
- y ⁇ a represents the lowest y value measured between 0° and 70°
- the optical measurement were performed thanks to a multichannel spectroscope (trade name: C10027) manufactured by Hamamatsu Photonics K.K..
- the angle the angle between a normal line direction of the element and a direction extending from the element to the spectroscope was defined as the measurement angle ⁇ (fig.21).
- the measurement was made while rotating the OLED to the spectroscope, thereby measuring the angular dependency of light emitting colour
- the voltage applied on each sample is the one required to obtain a current intensity of 6 mA.
- the resistance value (around 4 Q n) obtained for a translucent conductive substrate according to the invention are lower than the resistance value obtained with a classical ITO substrate (around 35 Q/n)
- Table III shows three columns with examples of translucent conductive substrates according to the invention comprising a scattering layer and having different types of electrodes (numbers of layers, chemical nature and thickness of layers) and the measurement results of resistance expressed in ⁇ /D.
- the general structure of the organic light-emitting device has been described above (p. 46, I. 19 to p. 48, I. 16).
- the improvement coating (120) comprises a barrier layer (1200), which is merged with an improvement layer (1201) and this layer is covered by a crystallisation layer (1202).
- Examples III.2 and III.3 illustrate translucent conductive substrates in conformity with the invention.
- Example III.3 illustrates a translucent conductive su bstrate in accordance with the invention having an electrode that is optimised with respect to the geometric thickness of the crystallisation layer (1102).
- Insertion layer (123) Zn x Sn y O z / Zn x Sn y O z / Zn x Sn y O z / 7.0
- the support ( 10) is a clear glass with a geometric thickness equal to 1.60 mm.
- the translucent conductive substrate according to the invention has an electrode that has at least one additional insertion layer ( 123) .
- the fu nction of th is insertion layer ( 123) is to form pa rt of a n optica l cavity that enables the metal cond uction layer to become transparent.
- no conductivity condition is imposed to obtain optical transparency values compatible with architectural applications.
- the layers developed for architectural application cannot be used directly for optoelectron ic a pplications, si nce they genera l ly conta in d ielectric compou nds and/or poorly conductive compounds.
- the geometric thickness of the insertion layer (E in ) ( 123) is such that, firstly, its ohmic th ickness is at most equal to 10 12 ohm, preferably at most equal to 10 4 ohm, wherein the ohmic thickness is equal to the relation between the resistivity of the material forming the insertion layer ( ⁇ ) / on the one hand, and the geometric thickness of this same layer (I), on the other; and secondly, the geometric thickness of the insertion layer ( 123) is l i n ked to the geometric thickness of the first organic layer of the organic light-emitting device (E org ), the term "first organic layer” denoting all the organic layers disposed between the insertion layer ( 123) and the organic light-emitting layer.
- a dielectric, i.e. poorly conductive, layer for contact between the conduction layer and the organic portion of the organic light-emitting device runs counter to the customarily accepted knowledge of a skilled person who has to manufacture organic light-emitting devices.
- the inventors have surprisingly found that the use of a dielectric, i.e. poorly conductive, material does not have to be excluded for the formation of the insertion layer (123).
- a conductive material is preferred.
- the voltages of use increase considerably, as shown in Table IV.
- Table IV shows two columns with examples of translucent conductive substrates according to the invention and having different types of electrodes (numbers of layers, chemical nature and thickness of layers) as well as the results of measurements of electrical performance obtained by means of the organic light-emitting device in which these substrates are incorporated.
- the general structure of the organic light-emitting device has been described above (p. 46, I. 19 to p. 48, I. 16).
- Example IV.1 is a translucent conductive substrate comprising an electrode based on a structure having a conduction layer of Ag (122), the electrode is not optimised.
- the improvement coating (120) comprises a barrier layer (1200), which is merged with an improvement layer (1201) and this layer is covered by a crystallisation layer (1202).
- the crystallisation (1202) and insertion (123) layers are of the same nature.
- example IV.1 also shows an insertion layer (123) with a geometric thickness that has not been optimised.
- Example IV.2 illustrates an optimised electrode
- the crystallisation (1202) and insertion (124) layers are of the same nature.
- These layers are made of Zn x Sn y O z (where x + y > 3 and z ⁇ 6), the Zn x Sn y O z preferably comprising at most 95% by weight of zinc, the percentage by weight of zinc being expressed in relation to the total weight of the metals present in the layer. It is evident that the electrical properties of example IV.2 are appreciably higher than those shown in example IV.1.
- the support (10) is a clear glass with a geometric thickness equal to 1.60 mm.
- Table V shows that with a constant geometric thickness of the insertion layer, it is possible to reduce the voltages of use, decreasing the resistivity of this layer.
- Table V shows three columns with examples of translucent conductive substrates, which are in accordance with the invention but differ from one another with respect to the natu re of the chemica l compou nd forming the insertion layer, as well as the resu lts of measu rements of electrica l a nd optica l performa nce obtained by means of the organic light-emitting device in which these electrodes are incorporated.
- the general structure of the organic light-emitti ng device has been described above (p. 46, I. 19 to p. 48, I. 16).
- Example V. l illustrates a translucent conductive substrate according to the invention that has an electrode with an insertion layer com p risi ng a con d uctive layer made of zi nc oxide doped w ith a l u m i n i u m (resistivity of ZnO:AI : 10 "4 Q*cm).
- Example V.2 illustrates a translucent conductive substrate according to the invention that has an electrode with an insertion layer comprising a poorly conductive layer made of Zn x Sn y O z (where x + y > 3 and z ⁇ 6), the Zn x Sn y O z preferably comprising at most 95% by weight of zinc, the percentage by weight of zinc being expressed in relation to the total weight of the metals present in the layer (resistivity of Zn x Sn y O z : 10 "2 Q*cm).
- Example V.3 illustrates a translucent conductive substrate according to the invention that has an electrode with an insertion layer comprising a dielectric layer of titanium dioxide (resistivity of Ti0 2 : 70 10 4 Q*cm).
- the voltage to be applied is lower in the case of a conductive insertion layer with a layer made from a conductive material than in the case of a layer made from a dielectric material.
- Insertion layer (123) ZnO:AI / 7.0 Zn x Sn y O z / Ti0 2 / 7.0
- Homogenisation layer (124) Ti n itride / Ti n itride / Ti nitride /
- the support (10) is a clear glass with a geometric thickness equal to 1.60
- Ta ble VI shows organ ic lig ht-emitting devices that emit a quasi-white light.
- the general structure of the organic light-emitting device that emit a quasi-white light whose performances are shown in Table VI have the following structure, starting with the translucent conductive substrate:
- NPD-2 N, N, N',N"-tetrakis(4-methoxyphenyl)-benzidine doped with 4 mole % of NPD-2
- NPB N,N'-di(naphthalen-l-yl)-N-N'-diphenyl-benzidine
- T TA 4,4',4"-tris(N-carbazolyl)- triphenylamine
- TBPi 2,2',2"(l,3,5-benzenetriyl) tris(l-phenyl- lH-benzidimazole)
- FirPic iridium-bis-(4,6- difluorophenyl-pyridinato-N,C2)-picolinate
- FirPic tris[2-(2- pyridinyl)phenyl-C,N] iridium
- Ir(ppy)3 iridium
- III iridium bis(2- methyldibenzo[f,h]quinoxaline
- TBPi 2,2',2"(l,3,5-benzenetriyl) tris-(l-phenyl-lH-benzimidazole)
- an upper reflective electrode composed of at least one metal.
- the metal of the upper reflective electrode consists of at least Ag.
- the metal of the upper reflective electrode consists of at least Al.
- Example VI.1 is a translucent conductive comprising an electrode based on a stacking structure having a conduction layer of Ag.
- Example VI.1 is a translucent conductive substrate according to the invention that comprises an electrode that is not optimised for an OLED having a homogenisation layer (124) and wherein the thickness of the improvement coating (120) lies outside the thickness range complying with equation:
- T ME T ME _o + [B * sin (n*T D i/T D i_o)]/(n S upport) 3
- the improvement coating (120) comprises a barrier layer (1200), which is merged with an improvement layer (1201) and this layer is covered by a crystallisation layer (1202).
- the crystallisation (1202) and insertion (123) layers are of the same nature. These layers are made of Zn x Sn y O z (where x + y > 3 and z ⁇ 6), the Zn x Sn y O z comprising at most 95% by weight of zinc, the percentage by weight of zinc being expressed in relation to the total weight of the metals present in the layer.
- example VI.2 more particularly illustrates a translucent conductive substrate having a fine metal layer and having a more significant thickness of coating for improving light transmission properties.
- the advantage of such thickness of the improvement coating is that:
- Example VI.3 illustrates a translucent conductive substrate having a thick silver layer that allows a conduction layer with a low resistance to be obtained.
- the comparison of the properties obtained for devices emitting quasi-wh ite l ig ht incorporating a translucent conductive substrate according to examples VI.1, VI.2 and VI.3 demonstrates that:
- Insertion layer (123) Zn x Sn y O z / Zn x Sn y O z / Zn x Sn y O z /
- the support ( 10) is a clear glass with a geometric thickness equal to 1.60 mm.
- the electrical performance levels are measured by applied voltages (V) to obtain a current of 2 mA/cm 2 .
- Table VII shows organic light-emitting devices that emit a quasi-white light.
- the general structure of the organic light-emitting device that emit a quasi-wh ite light whose performances are shown in Table VII have the following organ ic structu re, starting from the translucent conductive substrate:
- the upper reflective electrode is also composed of at least one meta l .
- the metal of the upper reflective electrode consists of at least Ag. According to an alternative embodiment, the metal of the upper reflective electrode consists of at least Al.
- the scattering layer (11) a nd the electrode (12) of the examples of tra nslucent conductive substrate (1 ) accord ing to the invention have been deposited following the conditions describe here above (p. 47, I . 1 to p. 48, I . 16), said scattering layer having, in example VII.2, th e sa me com position as th e com position u sed i n th e previous examples but comprising an additional amount of 15 vol .% of alumina particles having 3 ⁇ in diameter in examples VII.1 and VII.3.
- the layers based on TiO x and ZnO:AI are respectively deposited using a TiO x ceramic target at a pressu re of 0.5 Pa in an Ar/0 2 atmosphere and using a ZnO:AI cera mic target in an Ar/0 2 atmosphere, a weak percentage 0 2 being introduced (0-0,7 %), at a pressure of 0.5 Pa .
- Examples VII.1 and VII.2 are translucent conductive substrates comprising an electrode based on a stacking structure having a cond uction layer of Ag .
- Examples VII.1 and VII.2 are translucent conductive substrates according to the invention that comprise an electrode that is not optimised for a n OLED having a homogenisation layer (124) and wherein the thickness of the improvement coating ( 120) lies outside the th ickness range complying with equation :
- T ME T ME _o + [B * sin (n*T D i/T D i_o)]/(n S upport) 3
- the improvement coating (120) comprises a barrier layer (1200), a n i mprovement layer
- the Zn x Sn y O z prefera bly comprisi ng at most 95% by weight of zinc, the percentage by weight of zinc being expressed in relation to the total weight of the metals present in the layer.
- the sacrificial layer (121 b) is made of TiO x , said TiO x being a titan iu m oxide fu lly or partially oxidized .
- Insertion layer (123) Z n O : A I / Z n O : A I / ZnO:AI / 7.0
- Homogenisation layer (124) Ti nitride / Ti nitride / Ti nitride / 1.5
- the scattering layer comprises an additional amount of 15 vol.% of alumina particles having 3 ⁇ in diameter.
- OCE out-coupling coefficient efficiency
- the OCE were obtained by dividing the luminance values obtained by the value of the luminance measured for example I.IR.
- the optical measurement were performed thanks to a multi-channel spectroscope (trade name: C10027) manufactured by Hamamatsu Photonics K.K..
- the angle the angle between a normal line direction of the element and a direction extending from the element to the spectroscope was defined as the measurement angle ⁇ (fig. 21).
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Abstract
A translucent conductive substrate (1) for Organic Light Emitting Device comprising, a transparent support (10), a scattering layer (11) formed over the transparent support (10) and comprising a glass which contains a base material (110) having a first refractive index for at least one wavelength of light to be transmitted and a plurality of scattering materials (111) dispersed in the base material (110) and having a second refractive index different from that of the base material and a transparent electrode (12) formed over the scattering layer (11), said electrode (12) comprising at least one metal conduction layer (122) and at least one coating ( 120) having properties for improving the light transmission through said electrode, said coating (120) comprises at least one layer for improving light transmission (1201) and is located between the metal conduction layer (122) and the scattering layer (11), on which said electrode (12) is deposited.
Description
Translucent Conductive Substrate for Organic Light Emitting Devices
1. Field of the invention
The present invention relates to a translucent conductive su bstrate for Organic Light Emitting Devices (OLEDs), to the method for producing said translucent conductive substrate, to an Organic Light Emitting Diode incorporating said translucent conductive su bstrate and to the method for prod ucing sa id Orga n ic Light Emitting Device.
2. Background Art
An Organic Light Emitting Device (OLED) comprises at least an organic layer which is put between electrodes, a voltage is applied between the electrodes to inject holes and electrons, which are allowed to recombine in the organic layer, thereby an light is emitted by a light-emitting molecule in the course of a transition from a n excited state to a lower energy state. The Orga nic Lig ht Emitting Device is used for lighting display, backlight and lighting applications.
Sta rting from the su pport, OLEDs a re d ivided i nto th ree categories, bottom-emitting, top-emitting and transparent OLEDs. The bottom-emitting OLED uses a transparent or semi-tra nspa rent bottom electrode, the lig ht is emitted th roug h a transparent support. A top-emitting OLED uses a transparent or semi-transparent top electrode through said light is emitted, in other words the light is not emitted through the support. Finally, transparent OLED (T-OLED) uses transparent or semi-transparent electrodes on both sides of the device in such a way that the light can be emitted both through the top and the bottom electrode. As used herein, the expression "bottom electrode" is understood to denote the electrode which is the closest to the support.
In general, a bottom emitting OLED comprises at least one transparent electrode generally made from indium-doped tin oxide (ITO), a transparent support for su pporting the tra nspa rent electrode a nd a reflective cou nter electrode wh ich is generally made from calcium, silver or aluminium. The transparent support is made, for example, of glass, ceramic glass or polymer film. The refractive indexes of the different constituents of the OLED are in the range of 1.6-1.8 for the organic layers of the light- emitting device, 1.6 to 2.0 for the ITO layer, 1.4 to 1.6 for the supporting substrate and 1.0 for the outside air.
Organic light-emitting devices are ma n ufactu red with a good i nternal lig ht efficiency. Th is efficiency is expressed in terms of internal q uantu m efficiency
(IQE). Internal quantum efficiency represents the ratio between the number of photons obtained divided by the number of electrons injected. It lies in the order of 85%, even close to 100%, in known organic light-emitting devices. However, the efficiency of these devices is clea rly li mited by the losses associated with i nterface reflection phenomena due to the differences between the refractive indexes of the materials constituting the layers defining the interfaces. The losses as a result of reflection (R) occur at the interfaces and cause a reduction in external quantum efficiency (EQE). The external quantum efficiency is equal to the internal quantum efficiency minus the losses through reflection. As a result of a ll these combined losses, it is commonly accepted that the external quantum efficiency is generally in the range of 20% to 25% of the internal quantum efficiency.
Indium-doped tin oxide (ITO) is the material most widely used to form transparent electrodes. However, its use unfortunately causes some problems. Indeed indium resources are limited, which in the short term will lead to an inevitable increase in production costs for these devices. Moreover, because of the limited resistivity of ITO, it is essential to use a thick layer to obtain a sufficiently conductive electrode (i.e., an ITO layer having a resistance of around 5 Q/n requires a thickness such that the absorption of the electrode is increased). Moreover, thick ITO is generally more crystalline, causing an increase in the microscopic roughness of the surface, which must then be polished occasionally for use within organic light-emitting devices. For display applications, such ITO material may have sufficient conductivity because the pixels size is small, typically on the order of 1 mm or less. However, the cond uctivity of such transparent ITO electrodes can be insufficient for applications that require much larger emitting area such as lighting panel. Furthermore, indium present in organic light- emitting devices has a tendency to d iffuse i nto the orga n ic pa rt of these devices resulting in a reduction in the shelf and operating lifetime of these devices.
To solve these problems, d ifferent electrode structu res have been proposed . Docu ment WO 2008/029060 A2 d iscloses a tra nspa rent su bstrate, i n particular a transparent glass substrate, having a multilayer electrode with a complex stacking structure comprising a metal conductive layer and also having a base layer combin ing the properties of a barrier layer and an a ntireflective layer. This type of electrode enables layers with a low resistivity and a transparency at least equal to the electrode of ITO to be obtained, and these electrodes can be advantageously used in the field of large-surface light sources such as light panels. Moreover, these electrodes allow the quantity of indium used in their fabrication to be reduced or even suppressed entirely. However, although an antireflective layer in the form of a barrier layer is used, the solutions proposed in docu ment WO 2008/029060 A2 do not seek in a ny way to
optimize the a mount of lig ht emitted by an OLED limiting the losses associated with interface reflection phenomena. Furthermore, a colour variation of the light emitted by the OLED depending on the viewing angle is also observed.
3. Problems to be solved It is an aim of the invention to overcome the disadvantages of the prior art.
More precisely, an aim set by the present invention , i n at least one embodiment, is to provide a translucent conductive substrate for OLED that allows an increase in the amount of light transmitted in the forward direction th rough the substrate to be obtained, in other words an increase in the amount of light emitted by an OLED that it is incorporated into, i.e. in the case of a monochromic radiation . The term "monochromic" is understood to mean that a single colour (e.g . red, green, blue, white ...) is perceived by the eye without this light being monochromatic as such. In other words, monochromic radiation denotes a radiation covering a wavelength range and not a simple wavelength. Furthermore, the said translucent conductive substrate must be easy to manufacture.
An aim set of the present invention, in at least one embodiment, is to provide a translucent conductive su bstrate for OLED that allows to decrease, even to suppress, the amount of materials based on Indium, Indium oxide or a mixture thereof used to fabricate the transparent electrode which is comprised in the translucent conductive substrate.
Another aim set of the present invention, in at least one embodiment, is to provide a translucent conductive substrate that allows a decrease of the colour angular dependency of the light emitted by an OLED incorporating said translucent conductive substrate.
4. Invention disclosure
The present invention is directed to a translucent cond uctive substrate for Organic Light Emitting Device comprising :
• a transparent support, · a scattering layer formed over the transparent su pport a nd comprising a glass which contains a base material having a first refractive index for at least one wavelength of light to be transmitted and a plurality of scattering
materials dispersed in the base material and having a second refractive index different from that of the base material,
• a transpa rent electrode formed over the scattering layer, said electrode comprising at least one metal conduction layer, preferably a single metal conduction layer, and at least one coating having properties for improving the light transmission through said electrode, wherein said coating has a geometric thickness at least more than 3.0 nm and at most less than or equal to 200 nm,
The advantage provided by the substrate according to the invention is that it allows from one hand, an increase in the amount of light emitted by a OLED in the forward direction that incorporates it, i.e. in the case of monochromic radiation, and on the other hand, a decrease of the colour variation of the light emitted by the OLED depending on the viewing angle. Moreover, in the case of an organic light-emitting device emitting white light, the substrate according to the invention can be used with any known type of layered stacking structure forming the organic part of the OLED that emits white light.
The translucent conductive substrate of the present invention comprises a transparent support. The support will be considered to be transparent when it exhibits a light absorption of at most 50%, even at most 30%, preferably at most 20%, more preferred at most 10% at wavelengths i n the visi ble l ig ht ra nge . In a pa rticu la r embodiment the translucent conductive substrate according to the invention comprises a transparent support having a refractive index at least equal to 1.2, preferably at least equal to 1.4, more preferred at least equal to 1.5 at a wavelength of 550 nm. The advantage provided by using a support with a high refractive index is that it allows the amount of transmitted or emitted light in the forward direction to be increased with the same translucent conductive substrate structure.
The term "su pport" is also u nderstood to mean not only the support as such, but also any structure comprising the support as well as at least one layer of a material with a refractive index, nmateriai/ close to the refractive index of the support, nSUpPOrt, in other words | nSUpp0rt-nmatenai l ≤ 0.1. | nSUpp0rt-nmatenai l represents the absolute value of the difference between the refractive indexes. A silicon oxide layer deposited on a soda-lime-silica glass support can be cited as example. Th is layer is used to protect the glass surface against ageing before other layer would be deposited.
The function of the su pport is to support and/or protect the electrode. Th e su pport ca n be mad e of g lass, rig id p lastic mate ria l (e . g . orga n ic g la ss,
polycarbonate) or flexible polymer films (e.g. polyvinyl chloride (PVC), polyethylene terephthalate (PET), polypropylene (PP), polytetrafluoroethylene (PTFE)). The support is preferably rigid.
If the support is a polymer film, this preferably has a high refractive index, wherein the refractive index of the support (nSUpp0rt) has a value at least equal to 1.4, preferably at least equal to 1.5, more preferred at least equal to 1.6. nSUpp0rt represents the refractive index of the support at a wavelength of 550 nm. The advantage provided by using a support with a high refractive index is that it allows the amount of emitted light to be increased with the same substrate structure. If the support is made of glass, e.g. a sheet of glass, this preferably has a geometric thickness of at least 0.1 mm. The term "geometric thickness" is understood to mean the average geometric thickness. Glasses are mineral or organic. Mineral glasses are preferred. Of these, soda-lime-silica glasses that are clear or are bulk or surface coloured are preferred. More preferred, these are extra-clear soda-lime-silica glasses. The term extra-clear denotes a glass containing at most 0.020% by weight of the glass of total Fe expressed as Fe203 and preferably more than 0.015% by weight. Because of its low porosity, the glass has the advantage of assuring the best protection against any form of contamination of an OLED comprising the translucent conductive substrate according to the invention. A glass having a high refractive index is preferred, the refractive index of the glass has a value at least equal to 1.4, preferably at least equal to 1.5, more preferred at least equal to 1.6, most preferred at least equal to 1.7. Nevertheless, for reasons of cost, the refractive index of the glass, nsupport, preferably has a value in the range of between 1.4 and 1.6. More preferred, the refractive index of the glass has a value of about 1.5. nsupport represents the refractive index of the support at a wavelength of 550 nm. Advantageously, the glass support comprises at least one barrier layer on the face of the glass on which the scattering layer is deposited. This layer in particular allows the electrode to be protected from any contamination by the migration of alkaline substances coming from the support, e.g. made of soda-lime-silica glass, and thus enables the service life of the electrode to be extended. The barrier layer comprises at least one compound selected from the following: silicon oxide, aluminium oxide, titanium oxide, mixed oxide of zinc-tin, mixed oxide of zinc- aluminium, silicon nitride, aluminium nitride, titanium nitride, silicon oxynitride, aluminium oxynitride.
The substrate of the present invention comprises a scattering layer, wherein said scattering layer is formed over the transparent support and comprises a glass which contains a base material having a first refractive index for at least one wavelength of light to be transmitted and a plurality of scattering materials dispersed in
the base material and having a second refractive index different from that of the base material.
The scattering layer is formed by depositing a glass powder on the glass substrate by a method such as coating and firing it at a desired temperature. The said scattering layer has the base material having a first refractive index and a plurality of scattering materials dispersed in the above-mentioned base material and having a second refractive index different from that of the above-mentioned base material. As the scatteri ng layer, a materia l (base materia l) havi ng a ma i n su rface coated a nd having a high light transmittance may be used. As the base material, a glass, a crystallized glass, a translucent resin or a translucent ceramic may be used. As a material for the glass, an inorganic glass such as soda lime glass, borosilicate glass, non-alkali glass, low-alkali glass or quartz glass may be used. Incidentally, the plurality of scattering materials is formed in the inside of the base material. In an embodiment, the tra nslucent conductive su bstrate is so that the scattering materials are selected from pores, precipitated crysta ls, materia l pa rticles havi ng a d ifferent chem ica l composition than base material, phase-separated glass or mixtures from at least two thereof. The scattering materials are preferably selected from precipitated crystals, material particles having a different chemical composition than base material, phase- separated glass or mixtures from at least two thereof. The scattering materials are most preferably selected from phase-separated glass. The material particle as used herein as scattering material means a small solid material . In an embodiment, the translucent conductive substrate is so that the material particles used as scattering materials are selected from crystalline particles, amorphous particles or at least a mixture thereof. The material particles used as scattering materials may have the sa me or different chemical compositions, preferably the particles have the same chemical composition . The material constituting the particle is preferably selected from a ceramic material . The ceramic is selected from a ceramic oxide (Ti02, Zr02, Sn02, Zn02, Si02, Sb203, Al203, ZrSi04, preferably Ti02, Zr02, Al203, Si02), a ceramic non-oxide (carbides, borides, nitrides, silicides) or a composite ceramic (combinations of oxides and non-oxides ceramics). The particles are in the form of fillers (i .e., colloidal particles, aggregates, clusters,...)- In case of using the particles as the scattering materials, it is desirable to make the scattering layer by two layers. In th is case, it is desirable that the particle doesn't exist in the scattering layer in the upper layer. Furthermore, the pore means an air or gas material trapped within the base material. Furthermore, the phase-separated glass means a glass composed of two or more kinds of glass phases. Incidentally, when the scatteri ng materia l is the pore, the size of the scatteri ng materia l i nd icates a diameter of a void.
In an embodiment, the translucent conductive substrate according to the invention, is so that the distribution of the scattering materials in the scattering layer decreases from the inside of the scattering layer towards the face of the scattering layer opposite to the transparent support on which said scattering layer is deposited. Furthermore, in order to prevent inter-electrode short circuit of the OLED element, the main surface of the scattering layer is required to be smooth. For that purpose, it is unfavourable that the scattering materials protrude from the main surface of the scattering layer. Also in order to prevent the scattering materials from protruding from the main surface of the scattering layer, it is preferred that the scattering materials are not present within 1.0 μιτι, preferably 0.5 μιτι, most preferably 0.2 μιτι from the main surface of the scattering layer, in other words the face of the scattering layer opposite to the transparent support on which said scattering layer is deposited.
In an embodiment, the scattering layer is not limited to a single layer but may be two or more layers. In case that the scattering layer comprises a first layer part and a second layer part formed on the first layer part, it is preferable that the said second layer part is th in ner than the first layer part and the first layer part has the scattering materials much more than the second layer part. In particu lar, if the solid materia ls are used as the scattering materials, it is more preferable that the second layer part does not have the scattering materials except for an interface between the first and second layer parts. Due to the existence of the solid materials on the surface of the scattering layer has the possibility of causing the short circuit.
The su rface of the scatteri ng layer has cu rvatu re su rface with swell . Thereby, the swell means cycle R- a is at least 10 μιτι. The size of swell (roughness) means Ra is within the range from 0.01 μιτι to 5 μιτι. It is preferable that R- a is more than 10 μιτι and Ra/R- a is with i n a ra nge from 1.0*10"5 to 1.0*10_1, causing mirror function of an anode electrode to reduce. It is more preferable that R- a is more than 50 μιτι and Ra/R- a is within a range from 1.0*10"4 to 3.0*10"2. The Ra and the R- a used herein mean values calculated based on ISO 4287: 1997 (JIS B0601:2001), taking the short wavelength cutoff value as 25 μιτι and the long wavelength cutoff value as 2.5 mm.
Although both the refractive indexes of the scattering material and the base material may be high, the absolute value of the difference in the refractive indexes, | Δη | , is prefera bly 0.2 or more, | Δη | > 0.2, for at least one portion in the emission spectrum range of the scattering layer. In order to obtain sufficient scattering characteristics, the absolute value difference in the refractive indexes, |Δη | , is more preferably 0.2 or more, | Δη | > 0.2, over the whole region (430 n m to 650 nm) of the emission spectru m range or the whole region (360 nm to 830 n m) of the wavelength
range of visible light. The geometrical thickness of the scattering layer is in the range of 2 μιτι to 100 μιτι, preferably in the range of 10 μιτι to 60 μιτι.
Normally, the refractive index of the scattering layer must be equivalent to or higher than the refractive index of the transparent electrode material based on a transparent conductive oxide such as ITO. When the refractive index is low, a loss due to total reflection occurs at an interface between the base material and the translucent electrode material. The refractive index of the base material is only required to exceed for at least one portion (for example, red, blue, green or the like) in the emission spectrum range of the scattering layer. However, it exceeds preferably over the whole region (430 nm to 650 nm) of the emission spectrum range, and more preferably over the whole region (360 nm to 830 nm) of the wavelength range of visible light. The inventors have surprisingly found that this condition is not required with an electrode having a multilayered structure. The refractive i n dex of the scatteri n g layer is determined as follow, a glass having the same composition as the scattering layer is prepared and the refractive index of said glass is measured using a Shimadzu Device Corporation measurement apparatus brand name KPR2000 using a prism method.
In order to obtain the maximum refractive index difference, a scattering layer using a high refractive index glass as the above-mentioned h ig h l ig ht tra nsmitta nce materia l a nd the gas materia l, na mely the pores, as the scatteri ng material is desirable. In this case, the refractive index of the base material is desirably as high as possible, so that the high refractive index glass is preferably used as the base material. For components of the high refractive index glass, one or two or more kinds of components selected from P205, Si02, B203, Ge20 and Te02 can be used, as network formers, and one or two or more kinds of components selected from Ti02, Nb205, W03, Bi203, La203, Gd203, Y203, Zr02, ZnO, BaO, PbO and Sb203 as high refractive index components. In addition, in a sense of adjusting characteristics of the glass, an alkali oxide, an alkaline earth oxide, a fluoride or the like may be used within the range not impairing characteristics required for the refractive index. Specific glass systems include a B203-ZnO-La203 system, a P205-B203-R'20-R"0-Ti02-Nb205-W03-Bi203 system, a Te02-ZnO system, a B203-Bi203 system, a Si02-Bi203 system, a Si02-ZnO system, a B203-ZnO system, a P205-ZnO system and the like, wherein R' represents an alkali metal element, and R" represents an alkaline earth metal element. Incidentally, the above are examples, and the glass system is not construed as being limited to these examples as long as it is constituted so as to satisfy the above-mentioned conditions. In the invention, the scattering layer uses a glass conta ining 15 to 30 mol% of P205, 5 to 25 mol% of Bi203, 5 to 27 mol% of Nb203, 10 to 35 mol% of ZnO
and 5 mass% or less of the alkali metal comprising Li20, Na20 and K20 in terms of total amount thereof.
P205 is an essential component because it is a network former which is a skeleton of this glass system, and is a glass stabilizing element. However, when the content is too low, devitrification of the glass increases to result in failure to obtain the glass. Accordingly, it is preferably 15 mol% or more, and more preferably 18 mol% or more. On the other hand, when the content is too high, the refractive index decreases to result in failure to achieve the object of the invention. Accordingly, it is preferably 30 mol% or less, and more preferably 28 mol% or less. Therefore, the amount of P205 in the glass is advantageously comprised within the range of two of the preceding values, more advantageously within the range from 18 mol% to 28 mol%.
Bi203 is a com ponent i m provi n g the refractive i n dex, a nd ca n be introduced into the glass in relatively high amounts while keeping stability of the glass. Accordingly, the content is more than 5 mol%, preferably more than 10 mol%, and more preferably more than 13 mol%. However, excessive introduction thereof poses the problem of fabricating a rather coloured glass decreasing therefore the transmittance. Accordingly, the content is 25 mol% or less, preferably 23 mol% or less, and more preferably 20 mol% or less. Therefore, the amount of Bi203 in t h e g l a ss i s advantageously comprised within the range of two of the preceding values, preferably comprised within the range from 10 mol% to 23 mol%, more preferably from 13 mol% to 20 mol%.
Nb205 is an essential component improving the refractive index and also having an effect of enhancing weather resistance at the same time. Accordingly, the content is 5 mol% or more, preferably 7 mol% or more, and more preferably 10 mol% or more. On the other hand, when the content is too high, devitrification increases resulting in failure to obtain a glass. Accordingly, the content thereof is 27 mol% or less, preferably 20 mol% or less, and more preferably 18 mol% or less. Therefore, the amount of Nb205 in the glass is advantageously comprised with in the range of two of the preced i ng val ues, prefera bly with in the ra nge from 7 mol% to 20 mol%, more preferably within the range from 10 mol% to 18 mol%.
ZnO is a component improving the refractive index and decreasing the glass transition temperature. Accordingly, the content is 10 mol% or more, preferably 16 mol% or more, more preferably 18 mol% or more. However, when it is excessively added, devitrification of the glass increases resulting in failure to obtain a homogeneous glass. Accordingly, the content is 35 mol% or less, preferably 30 mol% or less, and more preferably 27 mol% or less. Therefore, the amount of ZnO in the glass is
advantageously comprised within the range of two of the preceding values, preferably with in the range from 16 mol% to 30 mol%, more prefera bly from 18 mol% to 27 mol%.
The alkali metal oxides ( 2O) such as Li20, Na20 and K20 has an effect of improving meltability to decrease the glass transition temperature and concurrently an effect of enhancing affinity with the glass substrate to increase adhesion. For th is reason, it is desirable for the mixture to contain one or two or more kinds of these said alkali metal oxides. When they are in excessive proportions, sta bility of the glass is impaired. In addition, these components tend to decrease the refractive index resulting in failure to the desired improvement of the light-extraction efficiency. Furthermore, a use of a low amount of alkali decreases the contamination risk of the electrode or the organic part of the OLED by these alkaline ions. Therefore, the total amount of alkali metal oxide is preferably less than 5% by mass, more preferably less than 2% by mass, particularly preferably not contain substantially. Ti02 is an optional component improving the refractive index. However, when the content is too high, colouring of the g lass increases to cause an increased loss in the scattering layer, resulting in failure to achieve the object of improving the light-extraction efficiency. Accordingly, the content is preferably up to 8 mol%.
B203 is an optional component as a component which is added into the glass, thereby improving resistance to devitrification and decreasi ng the therma l expansion coefficient. When the content is too high, the refractive index decreases. It is therefore preferably 17 mol% or less.
W03 is a n optiona l component i m provi ng the refractive i ndex a nd decreasing the glass transition temperature to decrease the firing temperature. However, excessive introduction thereof results in colouring of the g lass to cause a decrease in the light-extraction efficiency. Accordingly, the content thereof is preferably up to 20 mol%.
Te02 is an optional component having the effect of lowering the glass transition temperature while suppressing the excessive rise of thermal expansion. Accordingly, the content is preferably up to 7 mol%.
Ge02 is a n optiona l component havi ng the effect of a high refractive index. Accordingly, the content is preferably up to 7 mol%.
Sb203 is a n optiona l component having the effect of su ppressi ng the colour. Accordingly, the content is preferably up to 2 mol%.
Alkaline Earth Metal Oxides (MgO, CaO, SrO and BaO) are optional components improving the stability of the glass. However, excessive introduction thereof results in reducing the thermal expansion coefficient and refractive index. Accordingly, the total content thereof is preferably up to 10 mol%. Even if a component other than the above-mentioned components, we may add for the purposes of refining or an improvement of solubility, as long as it does not deviate from the efficiency of the present invention. Such components include, for example Si02, Al203, La203, Y2O3, Gd203, Zr02, Ta203, Cs20 and may also contain transition metal oxides. Their content is preferably less than 5 mol% in the total, more preferably less than 3 mol%, particularly preferably not contain substantially.
The glass of the present invention su bstantia lly does not contain lead oxide, less likely to cause environmental pollution.
The substrate of the present invention comprises a transparent electrode, wherein said electrode can act as an anode or conversely as a cathode, depending on the type of OLED in wh ich sa id electrode is inserted into. The expression "a coating having properties for improving light transmission" is understood to denote a coating whose presence in the stacking structure forming the electrode leads to an increase in th e a mou nt of l ig ht tra nsm itted th roug h th e su bstrate, e . g . a coati n g havi ng antireflective properties. In other words, an OLED incorporating the substrate according to the invention emits a higher amount of light compared to an OLED of the same type, but having a classic electrode (e.g. : an ITO layer) deposited on an identical support to that of the substrate according to the invention, the increase in the amou nt of light emitted is characterised by a higher luminance value, irrespective of the colour of the emitted light. The geometric thickness of the coating for improving light transmission must have a thickness at least greater than 3.0 nm, preferably at least equal to 5.0 nm, more preferred at least equal to 7.0 nm, most preferred at least equal to 10.0 nm. For example, when the coating for improving light transmission is based on zinc oxide or on zinc oxide under-stoichiometric in oxygen, ZnOx, wherein these zinc oxides are possibly doped or alloyed with tin, a geometric thickness of the coating for improving light transmission of at least more than 3.0 nm allows a metal conduction layer, particularly of silver, that has a good electrical conductivity to be obtained. The geometric thickness of the coating for improving light transmission advantageously has a thickness of less than or equal to 200.0 nm, preferably less than or equal to 170.0 nm, more preferred less than or equal to 130.0 nm, and the advantage of such thicknesses lies in the fact that the production process of said coating is quicker. Therefore, the geometric
thickness of the coating for improving light transmission is advantageously comprised within the range from 5.0 nm to 200.0 nm, preferably from 7.0 nm to 170.0 nm, more preferred from 10.0 nm to 130 nm.
The geometric thickness of the metal conduction layer is at least equal to 6.0 nm, preferably at least equal to 8.0 nm, more preferred at least equal to 10.0 nm at most equal to 29.0 nm, preferably at most equal to 27.0 nm, more preferred at most equal to 25.0 nm, most preferably at most equal to 22.0 nm. Therefore, the geometric thickness of the metal conduction layer is advantageously comprised within the range of two of the preceding values, preferably within the range from 6.0 nm to 29.0 nm, preferably from 8.0 nm to 27.0 nm, more preferred from 10.0 nm to 25.0 nm.
In a particular embodiment, the translucent conductive substrate is such that the transparent electrode formed over the scattering layer, said electrode comprising a single metal conduction layer and at least one coating having properties for improving the light transmission through said electrode, wherein said coating has a geometric thickness at least more than 3.0 nm and at most less than or equal to 200 nm, and said coating comprises at least one layer for improving light transmission and is located between the metal conduction layer and the scattering layer, on which said electrode is deposited, wherein the optical thickness of the coating having properties for improving the light transmission, TDi, and the geometric thickness of the metal conduction layer, TME, are linked by the equation:
TME = TME_o + [B * sin (n*TDi/TDi_o)]/(nSupport)3 where TME_O B and TDi_0 are constants with TME_O having a value in the range of 10.0 to 25.0 nm, B having a value in the range of 10.0 to 16.5 nm and TDi 0 having a value in the range of 23.9 * nDi to 28.3 * nDi nm, with nDi representing the refractive index of the coating for improving the light transmission at a wavelength of 550 nm and nSUpp0rt represents the refractive index of the support at a wavelength of 550 nm.
The optical thickness of a layer is obtained by multiplying the geometric thickness of said layer by the refractive index of the material constituting said layer. The value of the refractive index taken is the one at a wavelength of 550nm.
The inventors have surprisingly found that an electrode stacking structure based on the selection made by the equation linking the geometric thickness of the metal conduction layer, TME, to the optical thickness of the coating having properties for improving the light transmission, TDi, leads to an increase of the amount of light emitted by the OLED.
particular embodiment, the tra nsl ucent cond uctive su bstrate according to the invention is such that the transparent electrode formed over the scattering layer, said electrode comprising a single metal conduction layer and at least one coating having properties for improving the light transmission th rough said electrode, wherein said coating has a geometric thickness at least more than 3.0 nm and at most less than or equal to 200 nm, and said coating comprises at least one layer for improving light transmission and is located between the metal conduction layer and the scattering layer, on which said electrode is deposited, wherein the optical thickness of the coating having properties for improving the light transmission, TDi, and the geometric thickness of the metal conduction layer, TME, are linked by the equation :
TME = TM E_o + [B * sin (n*TDi/TDi_o)]/(nSs)3 where TME_O B a nd TDi_0 are constants with TME_O having a va lue in the range of 10.0 to 25.0 nm, B having a value in the range of 10.0 to 16.5 nm and TDi 0 having a value in the range of 23.9 * nDi to 28.3 * nDi nm, with nDi representing the refractive index of the coating for improving the light transmission at a wavelength of 550 nm and nss represents the refractive index of the stacking structure comprising the support and the scattering layer at a wavelength of 550 nm, where
nSUpport representing the refractive i ndex of tra nspa rent su pport at a wavelength of 550 nm, nscaUeringiayer representing the refractive index of the scattering layer at a wavelength of 550 nm, lsupport representing the geometrical thickness of the support and lSCattenngiayer representing the geometrical thickness of the scattering layer.
The inventors have surprisingly found that the selection of the electrode stacking structure based on the equation linking the geometric th ickness of the metal conduction layer to the optical thickness of the coating having properties for improving the light transmission, TDi, can be adapted in order to take into account the refractive index of the scattering layer (e.g., when the optical thickness of the scattering layer is more than or equal to 0.1 % of the optical thickness of the support).
In a pa rticu la r em bod i ment, the tra n sl ucent cond u ctive su bstrate according to the invention in such that the refractive index of the coating for improving light transmission is higher than the refractive index of the stacking structure comprising the support and the scattering layer at a wavelength of 550 nm.
In a particular embodiment the translucent conductive substrate according to the invention is such that the support has a refractive index, nSUpp0rt, in the range of between 1.4 and 1.6 at a wavelength of 550 nm and that the electrode is such that the optical thickness of the coating having properties for improving light transmission, TDi, and the geometric thickness of the metal conduction layer, TME, are linked by the equation:
TME = TME_o + [B * sin (n*TDi/TDi_o)]/(nSupport)3 where TME_O B and TDi_0 are constants with TME_O having a value in the range of 10.0 to 25.0 nm, preferably 10.0 to 23.0 nm, B having a value in the range of 10.0 to 16.5 nm and TDi 0 having a value in the range of 23.9 * nDi to 28.3 * nDi nm, with nDi representing the refractive index of the coating for improving the light transmission at a wavelength of 550 nm and nsupPort representing the refractive index of transparent support at a wavelength of 550 nm. Preferably, constants TME_O B and TDI 0 are such that TME_O has a value in the range of 10.0 to 23.0 nm, preferably 10.0 to 22.5 nm, more preferred 11.5 to 22.5 nm, B has a value in the range of 11.5 to 15.0 and TDi_o has a value in the range of 24.8 * nDi to 27.3 * nDi nm. More preferred, constants TME_o B and TDi_o are such that TME_O has a value in the range of 10.0 to 23.0 nm, preferably 10.0 to 22.5 nm, more preferred 11.5 to 22.5 nm, B has a value in the range of 12.0 to 15.0 and TDi 0 has a value in the range of 24.8 * nDi to 27.3 * nDi nm. According to a particular embodiment, the translucent conductive substrate according to the invention is such the support has a refractive index value, nSUpport in the range of 1.4 to 1.6 and is such that the geometric thickness of the metal conduction layer is at least equal to 6.0 nm, preferably at least equal to 8.0 nm, more preferred at least equal to 10.0 nm and at most equal to 22.0 nm, preferably at most equal to 20.0 nm, more preferred at most equal to 18.0 nm, the geometric thickness of the metal conduction layer is advantageously comprised within the range of two of the preceding values, preferably within the range from 6.0 nm to 22.0 nm, more preferably from 8.0 nm to 20.0 nm, the most preferably 10.0 nm to 18.0 nm, and wherein the geometric thickness of the coating for improving light transmission is at least equal to 50.0 nm, preferably at least equal to 60.0 nm and at most equal to 130.0 nm, preferably at most equal to 110.0 nm, more preferred at most equal to 90.0 nm, the geometric thickness of the coating for improving light transmission is advantageously comprised within the range of two of the preceding values, preferably within the range from 50.0 nm to 110.0 nm, more preferred from 60.0 nm to 90.0 nm. In a particular embodiment the translucent conductive substrate according to the invention is such that the support has a refractive index value, nSUpp0rt
in the range of 1.4 to 1.6 and is such that the geometric thickness of the metal conduction layer is at least eq ua l to 16.0 n m, preferably at least eq ual to 18.0 n m, more preferred at least equal to 20.0 nm and at most equal to 29.0 nm, preferably at most equal to 27.0 nm, more preferred at most equal to 25.0 nm, the geometric thickness of the metal conduction layer is advantageously comprised within the range of two of the preceding values, preferably within the range from 16.0 n m to 29.0 n m, more preferred from 18.0 nm to 27.0 nm, the most preferred from 20.0 nm to 25.0 nm, and wherein the geometric thickness of the coating for improving light transmission is at least equal to 20.0 nm and at most equal to 40.0 nm. Surprisingly, the use of a thick meta l cond uction layer com bi ned with a n opti m ised th ickness of the coati ng for improving light transmission allows OLEDs that have a high luminance to be obtained as well as a translucent conductive substrate, in which the electrode has a lower surface resistance expressed in Ω/D .
In a preferred embodiment the translucent conductive substrate according to the invention is such that the refractive index of the material forming the coating for improving light transmission (nDi) is higher than the refractive index of the support (nSUpPO rt) (nDi > nSUpPO rt), preferably nDi > 1.2 nSUpPO rt, more preferred nDi > 1.3 nSUpport/ most preferred nDi > 1.5 nSUpp0 rt. The refractive index of the material forming the coating (nDi) has a value ranging from 1.5 to 2.4, preferably rang ing from 2.0 to 2.4, more preferred ranging from 2.1 to 2.4 at a wavelength of 550 nm.
When the coating for improving the lig ht tra nsmission is formed from several layers, nDi is given by the equation : m
∑η
— x=i where m represents the layer n umber in the coating, nx represents the refractive index of the material forming the x"th layer sta rting from the support, lx represents the geometric thickness of the x"th layer, lDi represents the geometric thickness of the coating . The use of a material with a h igher refractive index allows a higher amount of emitted or transmitted light to be obtained. The advantage provided is all the more significant as the difference between the refractive index of the coating for i m provi ng the l ig ht tra nsm ission a nd the refractive i ndex of the su pport is substantial.
The material forming at least one layer of the coating for improving light transmission comprises at least one dielectric compound and/or at least one electrically
conductive compound . The term "dielectric compound" is understood to mean at least one compound selected from the following : the oxides of at least one element selected from Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Ni, Zn, Al, Ga, In, Si, Ge, Sn, Sb, Bi as well as a mixed oxide of at least two thereof nitrides of at least one element selected from boron, aluminium, silicon, germanium as well as a mixed nitride of at least two thereof; silicon oxynitride, aluminium oxynitride, mixed oxynitride of silicon-aluminum; silicon oxycarbide. If present, the d ielectric compou nd prefera bly comprises a n yttriu m oxide, a titanium oxide, a zi rcon i u m oxide, a hafn i u m oxide, a n iobi u m oxide, a tantalum oxide, a zinc oxide, a tin oxide, an aluminium oxide, an alu minium nitride, a silicon nitride and/or a silicon oxycarbide.
The term "cond uctive" is u nderstood to relate to a compou nd chosen from the following : oxides under-stoichiometric in oxygen and doped oxides of at least one element selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Zn, Al, Ga, In, Si, Ge, Sn, Sb, Bi as well as a mixed oxide under-stoichiometric in oxygen or a doped mixed oxide of at least two thereof; - doped nitrides of at least one element selected from boron, aluminium, silicon, germanium as well as a mixed doped nitride of at least two thereof; doped Si oxycarbide; the doping agents preferably comprise at least one of the elements chosen from Al, Ga, In, Sn, P, Sb, F. In the case of silicon oxynitride the doping agents comprise B, Al and/or Ga.
The cond uctive compou nd prefera bly comprises at least ITO a nd/or doped Sn oxide, wherein the doping agent is at least one element chosen from F and Sb, and/or doped Zn oxide, wherein the doping agent is at least one element chosen from Al, Ga, Sn , Ti . Accord ing to a preferred em bod iment, the inorgan ic chemica l compound comprises at least ZnOx (where x≤ 1) and/or ZnxSnyOz (where x + y > 3 and
z ≤ 6) . ZnxSnyOz prefera bly comprises at most 95% by tota l weig ht of the meta ls present in the layer.
The meta l con d u ction layer of the electrode form i n g a pa rt of the translucent conductive substrate according to the invention mainly assures the electrical conduction of said electrode. It comprises at least one layer composed of a metal or a mixture of metals. The generic term "mixture of metals" denotes the combinations of at least two metals in the form of an alloy or doping of at least one metal by at least one other meta l, wherein the metal and/or the mixtu re of metals comprises at least one element selected from Pd, Pt, Cu, Ag, Au, Al. The metal and/or mixture of metals preferably comprises at least one element selected from Cu, Ag, Au, Al. More preferred, the metal cond uction layer comprises at least Ag in pu re form or alloyed to another metal. The other metal preferably comprises at least one element selected from Au, Pd, Al, Cu, Zn, Cd, In, Si, Zr, Mo, Ni, Cr, Mg, Mn, Co, Sn. More preferred, the other metal comprises at least Pd and/or Au, preferably Pd. The inventors have fou nd that the geometric thickness of the metal conduction layer must be at least equal to 6.0 nm in order to obtain a good conductivity of the electrode, in other words a low electrical resistance.
According to a particular embodiment, the coating for improving the light transmission of the electrode forming a part of the translucent conductive substrate according to the invention comprises at least one additional crystallisation layer, wherein, in relation to the support, said layer is the layer fu rthest removed from the stacking structu re forming said coating . This layer allows a preferred growth of the metal layer, e.g. of silver, forming the metal conduction layer and thus allows favourable electrical and optical properties of the metal conduction layer to be obta i ned . It comprises at least one i norga n ic chemica l com pou nd . The i norga n ic chemical compound forming the crystallisation layer does not necessarily have a h igh refractive index. The inorganic chemical compound comprises at least ZnOx (where x≤ 1) and/or ZnxSnyOz (where x + y > 3 and z≤ 6). ZnxSnyOz preferably comprises at most 95% by weight of zinc, the percentage by weight of zinc being expressed in relation to the total weight of the metals present in the layer. The crystallisation layer is preferably composed of ZnO. Since the layer having properties for improving light transmission has a generally greater thickness than is usually encountered in the field of multilayer conductive coatings (e.g. low emission type coating), the thickness of the crystallisation layer must be ada pted or i ncreased to provide a meta l cond uction layer with good conduction and very low absorption.
According to a pa rticu lar embodiment, the geometric th ickness of the crystallisation layer is at least equal to 7% of the total geometric th ickness of the
coating for improving light transmission and preferably 11%, more preferred 14%. For example, in the case of a coating for improving light transmission comprising a layer for improving light transmission and a crystallisation layer, the geometric thickness of the layer for improving light transmission must be reduced if the geometric thickness of the crysta llisation layer is i ncreased in order to comply with the relation between the geometric thickness of the metal conduction layer a nd the optica l th ickness of the coating for improving light transmission.
According to a particular embodiment, the crystallisation layer is merged with at least one layer for i mprovi ng l ig ht tra nsm ission form i ng the coati ng for improving light transmission.
Accord ing to a particu lar embodiment, the coating for improving lig ht transmission comprises at least one additional barrier layer, wherein, in relation to the scattering layer, said barrier layer is the layer closest to the stacking structure forming said coating . Th is layer in pa rticula r a llows the electrode to be protected from any contamination by the migration of alkaline substances coming from the support, e.g . made of soda-lime-silica glass, or from the scattering layer and thus enables the service life of the electrode to be extended. The barrier layer comprises at least one compound selected from the following : titanium oxide, zircon ium oxide, alumin ium oxide, yttrium oxide as well as a mixed oxide of at least two thereof; mixed oxide of zinc-tin, zinc-aluminium, zinc-titanium, zinc-indium, tin-indium; silicon nitride, silicon oxynitride, silicon oxycarbide, silicon oxycarbonitride, aluminium nitride, aluminium oxynitride, a mixed nitride of aluminium-silicon, a mixed oxynitride of aluminium-silicon; - wherein this barrier layer is possibly doped or alloyed with tin.
According to a particular embodiment, the barrier layer is merged with at least one layer for improving light transmission forming the coating for improving light transmission.
According to a preferred embod iment of the barrier and crysta llisation layers, at least one of these two additional layers is merged with at least one layer for improving light transmission forming the coating for improving light transmission.
In a particular embodiment the translucent conductive substrate according to the invention is such that the electrode partly forming it comprises a thin
layer for homogenizing the surface electrical properties located, which, in relation to the scattering layer, is located at the top of the multilayer stacking structure forming said electrode. The main function of the thin layer for homogenizing the su rface electrica l properties is to allow a un iform transfer of charge to be obtained over the entire surface of the electrode. This uniform transfer is indicated by a balanced flux of emitted light at every point of the surface. It also enables the service life of the OLED to be increased, since this transfer is the same at each point, thus eliminating any possible hot spots. The homogenisation layer has a geometric thickness of at least 0.5 nm, preferably of at least 1.0 nm. The homogenisation layer has a geometric thickness of at most 6.0 n m, preferably at most 2.5 n m, more preferred at most 2.0 nm . It is more preferred that the homogenisation layer is equal to 1.5 nm. Therefore, the geometric thickness of the homogenisation layer is advantageously comprised within the range of two of the preceding values, preferably within the range from 0.5 nm to 6.0 nm, more preferably from 1.0 nm to 2.5 nm, the most preferably from 1.0 nm to 2.0 nm. The homogenisation layer comprises at least one layer composed of at least one inorganic material selected from a metal, a nitride, an oxide, a carbide, an oxynitride, an oxycarbide, a carbonitride, an oxycarbonitride.
Accord i n g to a fi rst pa rticu la r practica l exa m p le of th e p reviou s embodiment, the inorganic material of the homogenisation layer is composed of a single metal or a mixture of metals. The generic term "mixture of meta ls" denotes the combinations of at least two metals in the form of alloy or doping of at least one metal by at least one other metal. The homogenisation layer is composed of at least one element selected from Li, Na, K, Be, Mg, Ca, Ba, Sc, Y, Ti, Zr, Hf, Ce, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, B, Al, Ga, In, TI, C, Si, Ge, Sn, Pb. The metal and/or mixtu re of metals comprises at least one element selected from Li, Na, K, Mg, Ca, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Co, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Si, C. It is more preferred that the metal or the mixture of metals comprises at least one element selected from C, Ti, Zr, Hf, V, Nb, Ta, Ni, Cr, Al, Zn . The mixture of metals preferably comprises Ni-Cr and/or Zn doped with Al . The advantage provided by this particular example is that it allows a better possible compromise to be reached between the electrical properties resulting from the effect of the layer for homogenizing surface electrical properties, on the one hand, and the optical properties obtained as a result of the improvement coating, on the other. The use of a homogenisation layer that has the lowest possible thickness is a basic requirement. In fact, the influence of this layer on the amount of light emitted by the OLED is a ll the less when its th ickness is low. Therefore, if metallic, this homogenisation layer is distinguished from the conduction layer by its lower thickness, since this thickness is insufficient to assure conductivity. It
is therefore preferred that the homogenisation layer has a geometric thickness of 5.0 nm at most, if it is metallic, i.e. composed of a single metal or a mixture of metals.
According to a second particular embodiment, the inorganic material of the homogenisation layer is present in the form of at least one chemical compound selected from carbides, carbonitrides, oxynitrides, oxycarbides, oxycarbonitrides as well as mixtures of at least two thereof. The oxynitrides, oxycarbides, oxycarbonitrides of the homogenisation layer can be in non-stoichiometric, preferably under-stoichiometric, form in relation to oxygen . The carbides are carbides of at least one element selected from Be, Mg, Ca, Ba, Sc, Y, Ti, Zr, Hf, Ce, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Co, Rh, Ir, Ni, Pd, Pt, Cu, Au, Zn, Cd, B, Al, Si, Ge, Sn, Pb, preferably at least one element selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Co, Ni, Pd, Pt, Cu, Au, Zn, Cd, Al, Si, more preferred at least one element selected from Ti, Zr, Hf, V, Nb, Ta, Ni, Cr, Zn, Al. The carbonitrides are carbonitrides of at least one element selected from Be, Sc, Y, Ti, Zr, Hf, V, Nb, Cr, Mo, W, Fe, Co, Zn, B, Al, Si, preferably of at least one element selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Co, Zn, Al, Si, more preferred of at least one element selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Zn, Al. The oxynitrides are oxynitrides of at least one element selected from Be, Mg, Ca, Sr, Sc, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Co, Rh, Ir, Ni, Cu, Au, Zn, B, Al, Ga, In, Si, Ge, preferably of at least one element selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Co, Ni, Cu, Au, Zn, Al, Si, more preferred of at least one element selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Zn, Al. The oxycarbides are oxycarbides of at least one element selected from Be, Mg, Ca, Sr, Sc, Y, Ti, Zr, Hf, V, Nb, Cr, Mo, W, Mn, Fe, Ni, Zn, Si, Ge, preferably of at least one element selected from Ti, Zr, Hf, V, Nb, Cr, Mo, W, Mn, Ni, Zn, Al, Si, more preferred of at least one element selected from Ti, Zr, Hf, V, Nb, Cr, Zn, Al. The oxycarbonitrides are oxycarbonitrides of at least one element selected from Be, Ti, Zr, Hf, V, Nb, Cr, Mo, W, Mn, Zn, B, Al, Si, Ge, preferably of at least one element selected from Ti, Zr, Hf, V, Nb, Cr, Mo, W, Mn, Zn, Al, Sn, more preferred of at least one element selected from Ti, Zr, Hf, V, N b, Cr, Zn , Al . The ca rbides, ca rbon itrides, oxyn itrides, oxyca rbides, oxycarbonitrides of the layer for homogenizing surface electrical properties possibly comprise at least one doping element. In a preferred em bod i me nt, the th i n homogenisation layer comprises at least one oxyn itride composed of at least one element selected from Ti, Zr, Cr, Mo, W, Mn, Co, Ni, Cu, Au, Zn, Al, Si. More preferred the thin layer for homogenizing surface electrical properties comprises at least one oxynitride selected from Ti oxynitride, Zr oxynitride, Ni oxynitride, NiCr oxynitride. According to a third particular embodiment, the inorganic material of the homogenisation layer is present in the form of at least one metal nitride of at least one element selected from Be, Mg, Ca, Sr, Ba, Sc, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn,
Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, In, Si, Ge, Sn . Preferably, the homogenisation layer comprises at least one nitride of a n element selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Co, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Si. More preferred, the nitride comprises at least one element selected from Ti, Zr, Hf, V, Nb, Ta, Ni, Cr, Al, Zn. More preferred, the thin layer for homogenizing surface electrical properties comprises at least Ti nitride, Zr nitride, Ni nitride, NiCr nitride.
According to a fourth particular embodiment, the inorganic material of the homogenisation layer is present in the form of at least one metal oxide of at least one element selected from Be, Mg, Ca, Sr, Ba, Sc, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, In, Si, Ge, Sn, Pb. Preferably, the homogenisation layer comprises at least one oxide of a n element selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Co, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, In, Si, Sn. More preferred, the oxide comprises at least one element selected from Ti, Zr, Hf, V, Nb, Ta, Ni, Cu, Cr, Al, In, Sn, Zn. The oxide of the homogenisation layer can be a under-stoichiometric oxide in oxygen . The oxide possibly comprises at least one doping element. Preferably, the doping element is selected from at least one of the element chosen from Al, Ga, In, Sn, Sb, F, Ag. More preferred, the th in layer for homogenizing surface electrical properties comprises at least Ti oxide and/or Zr oxide a nd/or Ni oxide a nd/or N iCr oxide a nd/or ITO a nd/or doped Cu oxide, wherein the doping agent is Ag, and/or doped Sn oxide, wherein the doping agent is at least one element selected from F and Sb, and/or doped Zn oxide, wherein the doping agent is at least one element selected from Al, Ga, Sn, Ti.
In a particular embodiment the translucent conductive substrate according to the invention is such that the electrode partly forming it comprises at least one additional insertion layer located between the metal conduction layer and the thin homogenisation layer. The layer inserted between the metal conduction layer and the homogenisation layer comprises at least one layer composed of at least one dielectric com pou nd a nd/or at least one electrica l ly cond uctive compou nd . Prefera bly, the insertion layer comprises at least one layer composed of at least one conductive compound. The function of this insertion layer is to form a part of an optical cavity that ena bles the meta l cond uction layer to become tra nspa rent. The term "d ielectric compound" is understood to mean at least one compound selected from the following : the oxides of at least one element selected from Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Zn, Al, Ga, In, Si, Ge, Sn, Sb, Bi as well as the mixed oxide of at least two thereof:
the nitrides of at least one element selected from boron, aluminium, silicon, germanium as well as a mixed nitride of at least two thereof; silicon oxynitride, aluminium oxynitride, mixed oxynitride of silicon-aluminum; a silicon oxycarbide. If present, the d ielectric compou nd prefera bly comprises a n yttriu m oxide, a titanium oxide, a zirconium oxide, a hafnium oxide, a niobium oxide, a tantalum oxide, a zinc oxide, a tin oxide, an aluminium oxide, an alu minium nitride, a silicon nitride and/or a silicon oxycarbide.
The term "cond uctive" is u nderstood to relate to a compou nd chosen from the following : under-stoichiometric oxides in oxygen and doped oxides of at least one element selected from Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Zn, Al, Ga, In, Si, Ge, Sn, Sb, Bi as well as a mixed under-stoichiometric oxides in oxygen, a mixed doped oxides of at least two thereof; - doped nitrides of at least one element selected from boron, aluminium, silicon, germanium as well as a mixed doped nitride of at least two thereof; doped Si oxycarbide; the doping agents preferably comprise at least one of the elements chosen from Al, Ga, In, Sn, P, Sb, F. In the case of silicon oxynitride the doping agents comprise B, Al and/or Ga.
The cond uctive compou nd prefera bly comprises at least ITO a nd/or doped Sn oxide, wherein the doping agent is at least one element chosen from F and Sb, and/or doped Zn oxide, wherein the doping agent is at least one element chosen from Al, Ga, Sn , Ti . Accord ing to a preferred em bod iment, the inorgan ic chemica l compound comprises at least ZnOx (where x≤ 1) and/or ZnxSnyOz (where x + y > 3 and z ≤ 6). ZnxSnyOz prefera bly com prises at most 95% by weig ht of zi nc, a nd the percentage by weight of zinc is expressed in relation to the total weight of the metals present in the layer.
In a particular embodiment of the previous embodiment, the translucent conductive substrate according to the invention is such that the geometric thickness of the insertion layer (Ein) is such that its ohmic thickness is at most equal to 1012 ohm, preferably at most equal to 104 ohm, wherein the ohmic thickness is equal to the ratio
between the resistivity of the material forming the insertion layer (■), on the one hand, and the geometric thickness of this same layer (I), on the other; the geometric thickness of the insertion layer is, moreover, linked to the geometric thickness of the first organic layer of the organic light-emitting device (Eorg), the term "first organic layer" denoting all the orga n ic layers d isposed between the insertion layer and the organic light-emitting layer, by the equation : Eorg = A - Ein, where A is a consta nt having a value in the range of 5.0 to 75.0 nm, preferably from 20.0 to 60.0 nm, more preferred from 30.0 to 45.0 nm. The inventors have found that the equation Eorg = A - Ein surprisingly allows the geometric thickness of the first organic layer of the organic light-emitting device to be used to optimise the optical parameters (geometric thickness and refractive index) of the insertion layer a nd therefore to optimise the amou nt of light transmitted while retain ing a th ickness of the insertion layer that is compatible with the electrical properties that enable high ignition voltages, i.e. for a first luminance maximum, to be avoided. In another particular embodiment, the translucent substrate according to the invention is such that the geometric thickness of the insertion layer (Ein) is such that its ohmic thickness is at most equal to 1012 ohm, preferably at most equal to 104 ohm, wherein the ohmic thickness is equal to the ratio between the resistivity of the material forming the insertion layer (■), on the one hand; the geometric th ickness of this same layer (I), on the other; and the geometric thickness of the insertion layer is, moreover, linked to the geometric thickness of the first organic layer of the organic light-emitting device (Eorg), the term "first organic layer" denoting all the organic layers disposed between the insertion layer and the organic light-emitting layer, by the equation : Eorg = C - Ein, where C is a constant having a value in the range of 150.0 to 250.0 nm, preferably from 160.0 to 225.0 nm, more preferred from 75.0 to 205.0 nm. The inventors have found that the equation Eorg = C - Ein surprising ly allows the geometric thickness of the first organic layer of the organic light-emitting device to be used to optimise the optical parameters (geometric thickness and refractive index) of the insertion layer and therefore to optimise the amount of light transmitted while reta i n i ng a th ickness of the i nsertion layer that is compati ble with the electrica l properties that enable high ignition voltages, i.e. for a second luminance maximum, to be avoided.
In another particular embodiment of the translucent conductive substrate according to the invention is such that the metal conduction layer of the electrode comprises at least one sacrificial layer on at least one of its faces. Sacrificial layer is understood to mean a layer that can be fully or partially oxidised or nitrided . This layer allows deterioration of the metal conduction layer, in particular as a result of oxidation
or nitridation, to be avoided . Moreover, although it can be located between the metal cond uction layer and the crystallisation layer, the presence of this sacrificial layer is compatible with the action of a crysta llisation layer. If present, the sacrificial layer comprises at least one compound selected from metals, nitrides, oxides, under- stoichiometric metal oxides in oxygen. Preferably, the metals, nitrides, oxides, under- stoichiometric metal oxides in oxygen comprise at least one element selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Co, Ni, Cu, Zn, Al. The sacrificial layer preferably comprises at least Ti, Zr, Ni, Zn, Al . Most preferred, the sacrificial layer comprises at least Ti, TiOx (where x ≤ 2), NiCr, NiCrOx, TiZrOx (TiZrOx indicates a titanium oxide layer with 50% by weight of zirconium oxide), ZnAIOx (ZnAIOx indicates a zinc oxide layer with 2 to 5% by weig ht of a l u m i n i u m oxid e) . Accord i n g to a pa rtic u la r embod iment in keeping with the a bove, the th ickness of the sacrificia l layer has a geometric thickness of at least 0.5 nm. The thickness of the sacrificial layer comprises a thickness of at most 6.0 nm, preferably of at most 5.0 nm. It is more preferred if the thickness is equal to 2.5 nm. Therefore, the geometric thickness of the sacrificial layer is advantageously comprised within the range of two of the preceding values, preferably within the range from 0.5 to 6.0 nm, more preferably from 0.5 to 5 nm. According to a preferred em bod i ment, a sacrificia l layer is deposited on the face of the meta l conduction layer furthest removed in relation to the support. In another particular embodiment the translucent conductive substrate according to the invention is such that the stacking structure comprising the support and the scattering layer on which the electrode is deposited, comprises at least one functional coating on the face opposite the face, on which the electrode is deposited. Th is coating comprises at least one coating selected from an antireflective layer or multilayer stacking structure, a diffusion layer, a non-fogging or anti-soiling layer, an optical filter, in particular a titanium oxide layer, a selective absorbent layer, a micro- lens system such as those described in the article by Lin and Coll ., for example, in Optics Express, 2008, vol. 16, no. 15, pp. 11044-1105 1 o r i n d oc u m e n t U S 2003/0020399 Al, page 6. In a preferred embodiment the translucent conductive substrate according to the invention essentially has the following structure, starting from a clear or extra-clear glass support:
- a scattering layer formed over the transparent support and comprising a glass which contains a base material having a first refractive index for at least one wavelength of light to be transmitted and a plurality of scattering materials dispersed in the base material and having a second refractive index different
from that of the base material, sa id scatteri ng layer having a geometrica l thickness in the range of 10 μιτι to 60 μιτι, a coating for improving light transmission comprising :
• a layer for i mprovi ng lig ht transmission made of Ti02 (merged with the barrier layer),
• a crystallisation layer made of ZnO or ZnxSnyOz (where x + y > 3 and z≤ 6), a metal conduction layer made of Ag, wherein the geometric thickness of the coating having properties for improving light transmission and the geometric thickness of the metal conduction layer are linked by the equation :
TME = TME_o + [B * sin(n*TDi/TDi_o)]/(nSupport)3 where TME_O B a nd TDi_0 a re consta nts with TME_O having a value in the range of 10.0 to 25.0 nm, preferably 10.0 to 23.0 nm, B having a value in the range of 10.0 to 16.5 nm and TDi 0 having a value in the range of 23.9 * nDi to 28.3 * nDi nm, with nDi representing the refractive index of the coating for improving light transmission at a wavelength of 550 nm and nSUpPOrt represents the refractive index of the support at a wavelength of 550 nm. Preferably, constants TME_O B and TDi_0 are such that TME_O has a value in the ra nge of 10.0 to 23.0 nm, preferably 10.0 to 22.5 nm, more preferred 11.5 to 22.5 nm, B has a value in the range of 11.5 to 15.0 and TDi 0 has a value in the range of 24.8 * nDi to 27.3 * nDi nm. More preferred, constants TME_O B and TDi_0 are such that TME_o has a value in the range of 10.0 to 23.0 nm, preferably 10.0 to 22.5 nm, more preferred 11.5 to 22.5 nm, B has a value in the range of 12.0 to 15.0 and TDi 0 has a value in the range of 24.8 * nDi to 27.3 * nDi nm, a sacrificial layer: geometric th ickness 1.0-3.0 nm made of Ti or TiOx (x≤ 2), an insertion layer: geometric th ickness 3.0-20.0 n m made of ZnxSnyOz (where where x + y > 3 and z≤ 6), a homogenisation layer: geometric thickness 0.5-3.0 nm made of X, X nitride, X oxynitride where X: Ti, Zr, Hf, V, Nb, Ta, Ni, Pd, Cr, Mo, Al, Zn, Ni-Cr or Zn doped with Al .
In a preferred embodiment the translucent conductive substrate according to the invention essentially has the following structure, starting from a clear or extra-clear glass support:
- a scattering layer formed over the transparent support and comprising a glass which contains a base material having a first refractive index for at least one wavelength of light to be transmitted and a plurality of scattering materials dispersed in the base material and having a second refractive index different from that of the base material, said scattering layer having a geometrical thickness in the range of 10 μιτι to 60 μιτι,
- coating for improving light transmission :
• layer for improving light transmission made of Ti02 (merged with the barrier layer),
• crystallisation layer made of ZnO or ZnxSnyOz (where x + y > 3 and z < 6),
• th e g eo m et ri c th i c kn ess of t h e coat i n g fo r i m p rov i n g l i g ht transmission is at least equal to 50.0 nm, preferably at least equal to 60.0 nm, more preferred at least equal to 70.0 nm and at most equal to 100 nm, preferably at most equal to 90.0 nm, more preferred at most equal to 80.0 nm, therefore the geometric thickness of the coating from improving light transmission is advantageously comprised within the range of two of the preceding values, preferably within the range from 50.0 nm to 100.0 nm, more preferably from 60.0 nm to 90.0 nm, the most preferably from 70.0 nm to 80.0 nm.
- a metal conduction layer made of Ag, wherein the geometric thickness of the metal conduction layer is at least equal to 6.0 nm, preferably at least equal to 8.0 nm, more preferred at least equal to 10.0 nm and at most equal to 22.0 n m, prefera bly at most eq ual to 20.0 n m, more preferred at most equa l to 18.0 nm, therefore the geometric thickness of the metal conduction layer is advantageously comprised with in the range of two of the preced ing va lues, preferably within the range from 6.0 nm to 22.0 nm, more preferably from 8.0 nm to 20.0 nm, the most preferably from 10.0 nm to 18.0 nm.
- a sacrificial layer: geometric thickness 1.0-3.0 nm made of Ti or TiOx (x≤ 2),
- an insertion layer: geometric thickness 3.0-20.0 nm made of ZnxSnyOz (where where x + y > 3 and z≤ 6),
- a homogenisation layer: geometric thickness 0.5-3.0 nm made of X, X nitride, X oxynitride where X: Ti, Zr, Hf, V, Nb, Ta, Ni, Pd, Cr, Mo, Al, Zn, Ni-Cr or Zn doped with Al.
In a preferred embodiment the translucent conductive substrate according to the invention essentially has the following structure, starting from a clear or extra-clear glass support:
- a scattering layer formed over the transparent support and comprising a glass which contains a base material having a first refractive index for at least one wavelength of light to be transmitted and a plurality of scattering materials dispersed in the base material and having a second refractive index different from that of the base materia l, sa id scattering layer having a geometrica l thickness in the range of 10 μιτι to 60 μιτι,
- a coating for improving light transmission :
• a layer for improving light transmission made of Ti02 (merged with the barrier layer),
• a crystallisation layer made of ZnO or ZnxSnyOz (where x + y > 3 and z≤ 6),
• th e g eo m et ri c t h i c kn ess of th e coati n g fo r i m p rovi n g l i g ht transmission is at least equal to 20.0 nm and at most equal to 40.0 nm,
- a metal conduction layer made of Ag, wherein the geometric thickness of the metal conduction layer is at least equal to 16.0 nm, preferably at least equal to 18.0 n m, more preferred at least equal to 20.0 n m and at most eq ual to 29.0 n m, preferably at most eq ual to 27.0 n m and most preferred at most equal to 25.0 nm, therefore, the geometric thickness of the metal conduction layer is advantageously comprised with in the range of two of the preceding values, preferably within the range from 16.0 nm to 29.0 nm, more preferably from 18.0 nm to 27.0 nm, the most preferably from 20.0 nm to 25.0 nm.
- a sacrificial layer: geometric thickness 1.0-3.0 nm made of Ti or TiOx (x≤ 2),
- an insertion layer: geometric thickness 3.0-20.0 nm made of ZnxSnyOz (where where x + y > 3 and z≤ 6),
- a homogenisation layer: geometric thickness 0.5-3.0 nm made of X, X nitride, X oxynitride where X: Ti, Zr, Hf, V, Nb, Ta, Ni, Pd, Cr, Mo, Al, Zn, Ni-Cr or Zn doped with Al.
The embodiments of the translucent conductive substrate are not limited to the embodiments outlined a bove, but can equally be formed by combin ing two or more thereof.
The second subject of the invention relates to a method for the manufacture of the translucent conductive substrate according to the invention . Th is substrate comprises a support, a scattering layer and an electrode. The process for the manufacture of the translucent conductive su bstrate accord ing to the invention is a process, in which :
• the scattering layer is made as follow: oxide, phosphate, metaphosphate, carbonate, nitrate, hydroxide or other materials are used as starting materials to make the scattering layer. First, they are scaled to become the predetermined amount, and the collected materials are mixed. Then, the mixed materials are dissolved at a temperature of from 950 to 1500°C by using a platinum crucible and so on. Then, the dissolved materials are poured into a mould or the gap of twin roll. The poured materials are rapidly cooled in order to have a glass of the invention. There is a possibility of cooling gradually to remove the distortion, too. The invention is used in the form of glass frit which was prepared by the method above. The glass is crushed by using a mortar, ball mill, jet mill grinding due and so on or is classified if necessary to get the glass frit. Mass average particle size of glass frit is typically 0.5 to 10 microns. The surface of the glass frit can be reformed by a surfactant or a silane coupling agent. If necessary, it is also possible to mix the solvent, the binder, etc. and this glass frit. The mixed glass frit is coated on a transparent support and is fired at the temperature higher than about 60 °C in comparison with the glass transition temperature of the glass frit to cause the glass frit soften. After being cooled to room temperature, a transparent support with a scattering layer is obtained. As a solvent, ether type solvents (butyl carbitol (BC), butyl carbitol acetate (BCA), diethylene glycol di-n-butyl ether, dipropylene glycol dibutyl ether, tripropylene glycol butyl ether and butyl cellulosolve acetate), alcohol type solvents (■- terpineol, pine oil and Dowanol), ester type solvent (2,2,4 - trimethyl - 1,3 - pentanediol monoisobutyrate, and phtalic acid ester type solvents (DBP (dibutyl
phthalate), DMP (dimethyl phthalate) and DOP (dioctyl phthalate)) are used. Mainly used are - -terpineol and 2,2,4 - trimethyl - 1,3 - pentanediol monoisobutyrate. Incidentally, DBP (dibutyl phthalate), DMP (dimethyl phthalate) and DOP (dioctyl phthalate) also function as a plasticizer. As a binder, ethyl cellulose, nitrocellulose, an acrylic resin, vinyl acetate resin, a butyral resin, a melamine resin, an alkyd resin, a rosin resin or the like. Used as base resins are ethyl cellulose and nitrocellulose. Incidentally, a butyral resin, a melamine resin, an alkyd resin and a rosin resin are used as additives for improving coated film strength. Within the range where the purpose of this invention is not ruined, any ingredients other than binder or solvent may be introduced. In the case that the binder is used, before the glass frit is soften, it is desirable to contain the process of firing at a temperature that is lower than the glass transition temperature and evaporating the binder. The inventors have surprisingly found that the preferred firing temperature value is comprised in the range from 530 °C to 580 °C.
• the electrode is made by deposition on the scattering layer of at least one layer of the stacking structure constituting said electrode thanks to a method selected from cathodic sputtering techniques, possibly using a magnetic field, deposition techniques using plasma, CVD (chemical vapour deposition) and/or PVD (physical vapour deposition) techniques. The deposition method is preferably conducted under vacuum. The term "under vacuum" denotes a pressure lower than or equal to 2.0 Pa. More preferred, the process under vacuum is a magnetron sputtering technique. The process for the manufacture of the translucent conductive substrate comprises continuous processes, in which every layer forming the electrode is deposited immediately after the layer underlying it in the multilayer stacking structure (e.g. deposition of the stacking structure forming the electrode according to the invention onto a support that is a moving ribbon or deposition of the stacking structure onto a support that is a panel). The manufacturing process also comprises discontinuous processes in which a time interval (e.g. in the form of storage) separates the deposition of one layer and the layer underlying it in the stacking structure forming the electrode.
According to a preferred embodiment, the method for the manufacture of the translucent conductive su bstrate accord i ng to the i nvention is such that it is conducted in three phases as follows:
• deposition of the scattering layer on the transparent support
• deposition of the support of the coating having properties for improving light transmission,
• deposition of the metal conduction layer directly followed by deposition of the different functional elements forming the OLED system.
According to another preferred embodiment, the process for the manufacture of the translucent conductive substrate according to the invention is such that it is conducted in three phases as follows:
• deposition of the scattering layer on the transparent support
• deposition of the support of the coating having properties for improving light transmission through the electrode, the metal conduction layer, the sacrificial layer, the insertion layer,
• deposition of the homogenisation layer directly followed by deposition of the different functional elements forming the OLED system.
When the homogenisation layer or metal conduction layer are deposited at a later stage, the organic portion of the OLED is deposited immediately after deposition of the homogenisation layer or the metal conduction layer, i.e. without the homogenisation layer or the metal conduction layer being exposed before deposition of the organic portion of the OLED. The advantage provided by these processes is that oxidation of the conduction and homogenisation layers can be avoided when these are made of metal.
According to a particular embodiment, the layer for homogenizing the su rface electrica l properties based on oxides and/or oxynitrides ca n be obtained by direct deposition. According to an alternative example, the homogenisation layer based on oxides and/or oxynitrides can be obtained by oxidation of the meta ls a nd/or the correspond i ng n itrides (e.g . Ti is oxid ised i n Ti oxide, Ti n itride is oxid ised i n Ti oxynitride). This oxidation can occur directly or a long time after deposition of the homogenisation layer. The oxidation can be natural (e.g. through interaction with an oxidising compound present during the manufacturing process or during storage of the electrode before complete manufacture of the OLED) or can result from a post- treatment operation (e.g. treatment in ozone under ultraviolet light).
According to an alternative embodiment, the process comprises a n additional step of structuring the surface of the electrode. Structuring of the electrode is different from structuring of the support. This additional step consists of shaping the
su rface a nd/or decorating the su rface of the electrode. The process of shaping the surface of the electrode comprises at least engraving by laser or etching . The process of decorating the surface comprises at least a masking operation . Maski ng is the operation in which a portion at least of the surface of the electrode is covered with a protective coating as part of a post-treatment process, e.g . etch ing of the uncoated parts.
In a third object of the invention the translucent conductive substrate according to the present invention is incorporated into an OLED that emits light.
According to a variation of the previous embodiment, the organic light- em itti ng device com prises a n OLED system a bove the su bstrate accord i ng to the invention for the purpose of emitting a quasi-white light. Several methods are possible to produce a quasi-white light: by mixing within a single organic layer compounds that e m it red , g reen a n d b l u e l ig ht, by la m i n ati n g th ree orga n ic layer stru ctu res corresponding respectively to the emitter pa rts of red, g reen and blue lig ht or two organic layer structures (yellow and blue emission), by juxtaposing three (red, green blue emission) or two (yellow and blue emission) organic layer structures connected to a light diffusion system.
The term "quasi-white light" is understood to mean a light in which, with a perpendicular radiation to the surface of the substrate, the chromatic coordinates at 0° are contained in one of the eight chromaticity quadrilaterals, with contours of the quadrilaterals included . These quadrilaterals are defined in pages 10 to 12 of standard ANSI_NEMA_ANSLG C78.377-2008. These quadrilaterals are shown in Figure Al, part 1 entitled "Graphical representation of the chromaticity specification of SSL products in Table 1, on the CIE (x,y) chromaticity diagram". According to a particular embodiment, the organic light-emitting device is integrated into a glazing, a double glazing or a laminated glazing. It is also possible to integrate several organic light-emitting devices, preferably a large nu mber of organic light-emitting devices.
According to another particular embodiment, the organic light-emitting device is enclosed in at least one encapsulation material made of glass and/or plastic. The different embodiments of the organic light-emitting devices can be combined.
Finally, the different organic light-emitting devices have an extensive field of application. The invention concerns in particular possible uses of these organic light-emitting devices in the formation of one or more lu minous su rfaces. The term "lu minous su rface" includes, for exa mple, lighting tiles, lu minous panels, lu minous
pa rtitions, work su rfaces, g lasshouses, flash l ig hts, screen bases, d rawer bases, luminous roofs, touch screens, lamps, camera flash systems, luminous bases for display, security lights and shelves.
The translucent conductive substrate according to the invention will now be illustrated on the basis of the following figures. The figures show in a non-restrictive manner some substrate structu res. These figures are purely for illustration purposes and do not constitute a representation of structures to scale.
Figure 1 shows a cross-sectional view of a translucent conductive substrate according to the invention, wherein the substrate comprises a su pport, a scattering layer and an electrode formed from a stacking structu re consisting of a minimum number of layers.
Figure 2 shows a cross-sectional view of a translucent conductive substrate according to the invention in a second embodiment.
Figure 3 shows a cross-sectional view of a translucent conductive substrate according to the invention, wherein the substrate comprises a support having a barrier layer, a scattering layer and an electrode formed from a stacking structure consisting of a minimum number of layers and with a different function.
Figure 4 shows a cross-sectional view of the translucent conductive substrate according to the invention in a preferred embodiment. Figure 5 shows the evolution of the luminance of an organic light- emitting device emitting a quasi-white light and comprising a substrate without the scattering layer and having a transparent su pport with a refractive index of 1.4 at a wavelength equal to 550 nm as a function of the geometric thickness of the coating for improving the light transmission with a refractive index of 2.3 at a wavelength of 550 nm and of the geometric thickness of a metal conduction layer of Ag.
Figure 6 shows the evolution of the luminance of an organic light- emitting device emitting a quasi-white light and comprising a substrate without the scattering layer and having a transparent su pport with a refractive index of 1.5 at a wavelength equal to 550 nm as a function of the geometric thickness of the coating for improving the light transmission with a refractive index of 2.3 at a wavelength of 550 nm and of the geometric thickness of a metal conduction layer of Ag.
Figure 7 shows the evolution of the luminance of an organic light- emitting device emitting a quasi-white light and comprising a substrate without the
scattering layer and having a transparent su pport with a refractive index of 1.6 at a wavelength equal to 550 nm as a function of the geometric thickness of the coating for improving the light transmission with a refractive index of 2.3 at a wavelength of 550 nm and of the geometric thickness of a metal conduction layer of Ag. Figure 8 shows the evolution of the luminance of an organic light- emitting device emitting a quasi-white light and comprising a substrate without the scattering layer and having a transparent su pport with a refractive index of 1.8 at a wavelength equal to 550 nm as a function of the geometric thickness of the coating for improving the light transmission with a refractive index of 2.3 at a wavelength of 550 nm and of the geometric thickness of a metal conduction layer of Ag.
Figure 9 shows the evolution of the luminance of an organic light- emitting device emitting a quasi-white light and comprising a substrate without the scattering layer and having a transparent support with a refractive index of 2.0 at a wavelength equal to 550 nm as a function of the geometric thickness of the coating for improving the light transmission with a refractive index of 2.3 at a wavelength of 550 nm and of the geometric thickness of a metal conduction layer of Ag.
Figure 10 shows the photoluminescence as a function of the wavelength spectrum of a monochromic radiation, the main wavelength of which lies in the red light range. Figure 11 shows the photoluminescence as a function of the wavelength spectrum of a monochromic radiation, the main wavelength of which lies in the green light range.
Figure 12 shows the photoluminescence as a function of the wavelength spectrum of a monochromic radiation, the main wavelength of which lies in the blue light range.
Figure 13 shows the evolution of the luminance of the organic light- emitting device comprisi ng a su bstrate without the scattering layer a nd havi ng a transparent support, as a function of the geometric thickness and the refractive index of the layer for improving light transmission of the electrode according to the invention for a red light, wherein a metal conduction layer of Ag has a geometric thickness equal to 12.5 nm and a support has a refractive index of 1.5.
Figure 14 shows the evolution of the luminance of the organic light- emitting device com prisi ng a su bstrate without the scattering layer a nd having a transparent support, as a function of the geometric thickness and the refractive index
of the layer for improving light transmission of the electrode according to the invention for a green lig ht, wherein a meta l conduction layer of Ag has a geometric th ickness equal to 12.5 nm and a support has a refractive index of 1.5.
Figure 15 shows the evolution of the luminance of the organic light- emitting device comprisi ng a su bstrate without the scattering layer a nd havi ng a transparent support, as a function of the geometric thickness and the refractive index of the layer for improving light transmission of the electrode according to the invention for a blue light, wherein a metal conduction layer of Ag has a geometric thickness equal to 12.5 nm and a support has a refractive index of 1.5. Figure 16 shows the evolution of the luminance of the organic light- emitting device comprising a substrate without the scatteri ng layer a nd having a transparent support, as a function of the geometric thickness and the refractive index of the layer for improving transmission of the electrode according to the invention for a red light, wherein a metal conduction layer of Ag has a geometric thickness equal to 12.5 nm and a support has a refractive index of 2.0.
Figure 17 shows the evolution of the luminance of the organic light- emitting device comprisi ng a su bstrate without the scattering layer a nd havi ng a transparent support, as a function of the geometric thickness and the refractive index of the layer for improving light transmission of the electrode according to the invention for a green lig ht, wherein a meta l conduction layer of Ag has a geometric th ickness equal to 12.5 nm and a support has a refractive index of 2.0.
Figure 18 shows the evolution of the luminance of the organic light- emitting device comprisi ng a su bstrate without the scattering layer a nd havi ng a transparent support, as a function of the geometric thickness and the refractive index of the layer for improving light transmission of the electrode according to the invention for a blue light, wherein a metal conduction layer of Ag has a geometric thickness equal to 12.5 nm and a support has a refractive index of 2.0.
Figure 19 shows the evolution of the simulated reflection, expressed in D65 at 2° in accordance with European standard EN 410, of a substrate without the scattering layer and having a transparent support, said support having a refractive index equal to 1.5 at a wavelength equal to 550 nm, as a fu nction of the geometric thickness of the coating for improving light transmission and of the geometric thickness of the metal conduction layer of Ag, wherein above the conduction layer the substrate also comprises a sacrificial layer of TiOx that has a geometric thickness equal to 3.0 nm and an insertion layer of ZnxSnyOz (where x + y > 3 and z ≤ 6) that has a geometric
th ickness eq ua l to 14.7 n m, wherei n the insertion layer is coated with an orga n ic medium with a refractive index equal to 1.7 at a wavelength of 550 nm.
Figure 20 shows the evolution of the luminance of the organic light- emitting device incorporating a substrate without the scattering layer and having a transparent support, said support having a refractive index of 1.5 at a wavelength of 550 nm and a metal conduction layer with a geometric thickness of 12.5 n m as a function of the geometric thicknesses of the insertion layer (Ein) and the first organic layer of the electrode for a green light.
Figure 21 shows a measurement device for measuring the light emitting luminance and the angular dependency light-emitting colour.
Figure 1 shows an example of stacking structu re forming a translucent conductive substrate according to the invention. The translucent conductive substrate (1) has the following structure, starting from the transparent support (10):
• a scattering layer (11) formed over the transparent support (10) and comprising a glass which contains a base material (110) having a first refractive index for at least one wavelength of light to be transmitted and a plurality of scattering materials (111) dispersed in the base material (110) and having a second refractive index different from that of the base material,
• an electrode (12) constituted by : · a coating for improving light transmission (120) comprising a layer for improving light transmission (1201),
• a metal conduction layer (122)
Figure 2 shows an alternative example of the translucent conductive substrate according to the invention . Th is comprises, in addition to the layers already present in Figure 1 constituting the electrode (12), an insertion layer (123) and a layer for homogenizing surface electrical properties (124). The translucent conductive substrate has the following structure, starting from the support (10):
• a scattering layer (11) formed over the transparent support (10) and comprising a glass which contains a base material (110) having a first refractive index for at least one wavelength of light to be transmitted and a plurality of scattering materials (111) dispersed in the base material (110) and having a second refractive index different from that of the base material,
• an electrode (12) constituted by :
• a coati ng for i mproving l ig ht tra nsmission ( 120) comprising a layer for improving light transmission (1201)
• a metal conduction layer (122) · an insertion coating (123)
• a homogenisation coating (124)
Figure 3 shows another translucent substrate according to the invention. This comprises, in addition to the layers already present in Figure 2 constituting the electrode, an additional barrier layer (1200) and an additional crystallisation layer (1202) belonging to the coating for improving light transmission (120), two sacrificial layers (121a, 121b). Furthermore, the translucent conductive substrate according to the invention comprises also a barrier layer (9b) located between the support (10) and the scattering layer (11) and a functional coating (9a) on the second face of the transparent support (10). The translucent conductive substrate has the following structure, starting from the second face of the support (10):
• a functional coating (9a)
• a transparent support (10)
• a barrier layer on the support (9b)
• a scattering layer (11) formed over the transparent support (10) and comprising a glass which contains a base material (110) having a first refractive index for at least one wavelength of light to be transmitted and a plurality of scattering materials (111) dispersed in the base material (110) and having a second refractive index different from that of the base material,
• an electrode (12) constituted by : · a coating for improving light transmission (120) comprising : o a barrier layer (1200) o a layer for improving light transmission (1201) o a crystallisation layer (1202)
• a sacrificial layer (121a)
• a metal conduction layer (122)
• a sacrificial layer (121b)
• an insertion layer (123)
• a homogenisation layer (124) Figure 4 shows another example of a translucent substrate according to the invention. The substrate has the following structure, starting from the support (10):
• a scattering layer (11) formed over the transparent support (10) and comprising a glass which contains a base material (110) having a first refractive index for at least one wavelength of light to be transmitted and a plurality of scattering materials (111) dispersed in the base material (110) and having a second refractive index different from that of the base material,
• an electrode (12) constituted by :
• a coating for improving light transmission (120) comprising : o a layer for improving light transmission (1201) o a crystallisation layer (1202)
• a sacrificial layer (121a)
• a metal conduction layer (122)
• a sacrificial layer (121b)
• an insertion layer (123) · a homogenisation layer (124)
Figures 5, 6, 7, 8 and 9 show the evolution of the l u m ina nce of a n organic light-emitting device emitting a quasi-white light as a function of the geometric thickness of the coating for improving the l ight transmission (Dl ) with a refractive index of 2.3 (nDi) at a wavelength of 550 nm, and of the geometric thickness of a metal conduction layer of Ag and comprising a support with a refractive index equal to 1.4, 1.5, 1.6, 1.8 and 2.0 respectively at a wavelength equal to 550 nm. The structure of the organic light-emitting device comprises the following stacking structure:
• support (10) having a geometric thickness equal to 100.0 nm
• electrode (12): o coating for improving the light transmission (120), o metal conduction layer made of Ag (122),
• the organic portion of the organic light-emitting device is such that it has the following structure: o a hole transporting layer, HTL, having a geometric thickness equal to 25.0 nm, o an electron blocking layer, EBL, having a geometric thickness equal to 10.0 nm, o an emissive layer emitting a Gaussian spectrum of white light corresponding to illuminant A and having a geometric thickness equal to 16.0 nm, o a hole blocking layer, HBL, having a geometric thickness equal to 10.0 nm, o an electron transporting layer, ETL, having a geometric thickness equal to 43.0 nm. o a counter-electrode made of Al having a thickness equal to 100.0 nm.
These calculations show that a maximum luminance is obtained for a substrate without scattering layer such that the optical thickness of the coating having properties for improving light transmission (120), TDi, and the geometric thickness of the metal conduction layer (122), TME, are linked by the following equation:
TME = TME_o + [B * sin (n*TDi/TDi_o)]/(nSupport)3 where TME_O B and TDi_0 are constants with TME_O having a value in the range of 10.0 to 25.0 nm, B having a value in the range of 10.0 to 16.5 nm and TDi 0 having a value in the range of 23.9 * nDi to 28.3 * nDi nm, with nDi representing the refractive index of the coating for improving the light transmission at a wavelength of 550 nm and nSUpp0rt represents the refractive index of the support at a wavelength of 550 nm. The luminance was calculated using the program SETFOS, version 3 (Semiconductive Emissive Thin Film Optics Simulator) from Fluxim. This luminance is expressed as arbitrary unit. The sine curves appearing in the form of thicker lines indicate extreme values in the area selected by the equation TME = TME_O + [B * sin
(n*TDi/TDi_o)]/(risupport)3- The inventors have found surprisingly the area selected is not only valid for an organic device emitting quasi-wh ite lig ht but a lso for a ny type of colour emitted (e.g. red, green, blue). Moreover, the inventors have surprisingly found that the area selected by the equation TME = TME_O + [B * sin (n*TDi/TDi_o)]/(nSupport)3 for a substrate without scattering layer could also be used for a translucent conductive substrate according to the invention comprising a scattering layer located between the support and the electrode.
The inventors have found that, with the same structure of substrate without scattering layer (11), the use of a su pport (10) with a h ig h refractive index enables the amount of light emitted by the OLED to be increased . A hig h refractive index is understood to be a refractive index at least equal to 1.4, preferably at least equal to 1.5, more preferred at least equal to 1.6, most preferred at least equal to 1.7. In fact, as comparison of Figures 5 and 9 shows, an increase in the order of 180% in the luminance of the OLED is observed when, with the same structure of substrate without scattering layer, a support with a refractive index equal to 2.0 is used instead of a support with a refractive index equal to 1.4, wherein the refractive index of the support is the refractive index at a wavelength of 550 nm. The same evolution is also observed for the translucent conductive substrate according to the invention.
Figures 10 to 19, more particularly figures 13 to 19, relate to an example of a substrate without scattering layer that corresponds to a conduction layer of Ag having a geometric thickness equal to 12.5 nm. In these figures, the substrate without scattering layer is incorporated into an OLED emitting a red, green or blue colour. The structure of the organic light-emitting device comprises the following stacking structure: · support (10) having a geometric thickness equal to 100.0 nm
• electrode (12): o coating for improving the light transmission (120), o metal conduction layer made of Ag (122),
• the organic portion of the organic light-emitting device is such that it has the following structure: o a hole transporting layer, HTL, having a geometric thickness equal to 25.0 nm,
o an electron blocking layer, EBL, having a geometric thickness equal to 10.0 nm, o an emissive layer causing emission of a spectrum of red, green or blue light, of which the (x, y) chromatic coordinates are respectively equal to coordinates (0.63, 0.36), (0.24, 0.68) or (0.13, 0.31) in the CIE 1931 colorimetric diagram, according to which the device is provided for the emission of red, green or blue light, and having a geometric thickness equal to 16.0 nm, o a hole blocking layer, HBL, having a geometric thickness equal to
10.0 nm, o an electron transporting layer, ETL, having a geometric thickness equal to 43.0 nm. o a counter-electrode made of Al having a thickness equal to 100.0 nm.
Figures 10, 11 and 12 respectively show the evolution of the photoluminescence as a function of the wavelength spectra of a monochromic radiation, the main wavelength of which lies in the red, green or blue light range. Main wavelength is understood to mean the wavelength at which the photoluminescence is at its maximum. The term "monochromic" is understood to mean that a single colour is perceived by the eye without this light being monochromatic as such. Photoluminescence is expressed in the form of the relation between the value of the photoluminescence at a wavelength divided by the value of maximum photoluminescence. Therefore, the photoluminescence is a number without unit in the range of between 0 and 1. These figures clearly show that the light emitted by the OLED cannot be simply limited to a single wavelength. Figure 10 shows that at a wavelength equal to 616 nm, the photoluminescence is at maximum in the case of monochromic radiation, the main wavelength of which lies in the red colour range. Figure 11 shows that at a wavelength equal to 512 nm, the photoluminescence is at maximum in the case of monochromic radiation, the main wavelength of which lies in the green colour range. Figure 12 shows that at a wavelength equal to 453 nm, the photoluminescence is at maximum in the case of monochromic radiation, the main wavelength of which lies in the blue colour range.
Figures 13, 14 and 15 show the development of the luminance of the organic light-emitting device as a function of the geometric thickness (Dl) and the refractive index of the coating for improving the light transmission (nDi) (120) of the substrate without scattering layer , respectively for a red, green and blue light colour,
and for a support having a refractive index of 1.5 at a wavelength of 550 nm, wherein the geometric th ickness of a metal conduction layer of Ag is equal to 12.5 n m. Th is calculation was conducted not by taking into account a luminous radiation limited to a single wavelength, but by taking into account the real spectrum of wavelengths, as shown in Figures 10, 11 and 12. Surprisingly, these calculations show that a maximum luminance is obtained for a translucent conductive substrate without scattering layer that is such that the optical thickness of the coating having properties for improving light transmission (120), TDi, and the geometric thickness of the metal conduction layer (122), TME, are linked by the following equation : TME = TM E_0 + [B * Si n (n*TDi/TDi_o)]/(nSupport) 3 where TME_O B a nd TDi_0 are constants with TME_O having a va lue in the range of 10.0 to 25.0 nm, B having a value in the range of 10.0 to 16.5 nm and TDi 0 having a value in the range of 23.9 * nDi to 28.3 * nDi nm, with nDi representing the refractive index of the coating for improving the light transmission at a wavelength of 550 n m a nd nSUpp0rt represents the refractive index of the su pport at a wavelength of 550 nm. The luminance was calculated using the program SETFOS, version 3 (Semiconductive Emissive Thin Film Optics Simulator) from Fluxim.
For the special case outlined above, the substrate without scattering layer having a support with a refractive index equal to 1.5 at a wavelength of 550 nm and a conduction layer of Ag with a geometric thickness equal to 12.5 nm, it is evident on the basis of figures 13, 14, 15, obtained for an OLED emitting a red, green and blue lig ht respectively, that a h ig h l u mi na nce is obta i ned more pa rticu la rly when the geometric thickness of the coating for improving light transmission is at least equal to 50.0 nm, preferably at least equal to 60.0 nm, more preferred at least equal to 70.0 nm and at most equal to 110.0 nm, preferably at most equal to 100.0 nm, more preferred at most equal to 90.0 nm, most preferred at most equal to 80.0 nm. Moreover, on the basis of Figure 6, which describes the evolution of the luminance of an organic light- emitting device emitting a quasi-white light and having a support with a refractive index of 1.5 at a wavelength equal to 550 nm as a function of the geometric thickness of the coating for improving light transmission having a refractive index of 2.3 at a wavelength of 550 nm, and of the geometric thickness of a metal conduction layer made of Ag, it is evident that, for a substrate with a thickness of metal conduction layer of Ag of 12.5 nm, the optimu m geometric thickness of the coating for improving light transmission must be in the range of between 50.0 nm and 130.0 nm. The same observation is done with a translucent conductive substrate according to the invention.
Figures 16, 17 and 18 show the evolution of the luminance of the organic light-emitting device as a function of the geometric thickness (Dl) and the refractive index of the coating for improving the light transmission (nDi) (120) of the substrate without a scattering layer, respectively for a red, green and blue light colour, and for a support having a refractive index of 2.0 at a wavelength of 550 nm, wherein the geometric thickness of a metal conduction layer of Ag is equal to 12.5 nm. This calculation was conducted not by taking into account a luminous radiation limited to a single wavelength, but by taking into account the real spectrum of wavelengths, as shown in Figures 10, 11 and 12. Surprisingly, these calculations also show that a maximum luminance is obtained for a translucent conductive substrate without scattering layer which is such that the optical thickness of the coating having properties for improving light transmission (120), TDi, and the geometric thickness of the metal conduction layer (122), TME, are linked by the following equation:
TME = TME_o + [B * sin (n*TDi/TDi_o)]/(nSupport)3 where TME_O B and TDi_0 are constants with TME_O having a value in the range of 10.0 to 25.0 nm, B having a value in the range of 10.0 to 16.5 nm and TDi 0 having a value in the range of 23.9 * nDi to 28.3 * nDi nm, with nDi representing the refractive index of the coating for improving the light transmission at a wavelength of 550 nm and nSUpp0rt represents the refractive index of the support at a wavelength of 550 nm. The luminance was calculated using the program SETFOS, version 3 (Semiconductive Emissive Thin Film Optics Simulator) from Fluxim.
For the special case outlined above, it is evident on the basis of Figures 16, 17, 18, obtained for an OLED emitting a red, green and blue light respectively, that a high luminance is obtained more particularly when the geometric thickness of the coating for improving light transmission is at least equal to 40.0 nm, preferably at least equal to 50.0 nm, more preferred at least equal to 60.0 nm and at most equal to 110.0 nm, preferably at most equal to 100.0 nm, more preferred at most equal to 90.0 nm. Therefore, the geometric thickness of the coating for improving light transmission is advantageously comprised within the range of two of the preceding values, preferably comprised within the range from 40.0 nm to 110.0 nm, more preferably from 50.0 nm to 100.0 nm, the most preferably from 60.0 nm to 90.0 nm. Moreover, on the basis of Figure 9, which describes the development of the luminance of an organic light-emitting device emitting a quasi-white light and having a support with a refractive index of 2.0 at a wavelength equal to 550 nm as a function of the geometric thickness of the coating for improving light transmission having a refractive index of 2.3 at a wavelength of 550 nm, and of the geometric thickness of a metal conduction layer made of Ag, it is evident that, for a substrate with a thickness of metal conduction layer of Ag of 12.5
nm, the optimu m geometric thickness of the coating for improving light transmission must be at least greater than 3.0 nm and at most equal to 200.0 nm. The sa me observation is done with a translucent conductive substrate according to the invention.
Figures 13 to 18 all show that with the same substrate structu re in the case of a fixed refractive index of the support, a more significant luminance is obtained when the refractive index of the coating for improving light transmission (110) is higher than the refractive index of the support (10), particularly when nDi > 1.2*nSUpp0rt, more particularly when nDi > 1.3*nSUpp0rt, most particularly when nDi > 1.5*nsu pport. The refractive index of the material forming the coating (nDi) has a value ranging from 1.5 to 2.4, preferably ranging from 2.0 to 2.4, more preferred ranging from 2.1 to 2.4, at a wavelength of 550 nm. The same observation is done with a translucent cond uctive substrate according to the invention.
Surprisingly, the inventors have found that the optimum thickness of the improvement coating to obtain a maximum luminance, in other words a high emission level, depends little on the wavelength spectru m of the monochromic radiation (blue, g reen or red lig ht), as demonstrated i n Fig u res 13 to 18. More su rprisi ng ly, th is optimum lies in the same range of geometric thickness of the improvement coating (120). For example, in the case of a material with a refractive index ranging from 2.0 to 2.3, the geometric thickness of the improvement coating that enables an optimum emission at different wavelengths has a value ranging from 45.0 to 95.0 nm. This range is centred on and around a geometric thickness value of 70.0 nm. Moreover, respective comparisons of Figu res 8 and 11 for red light, Figu res 9 a nd 12 for g reen lig ht a nd Figures 10 and 13 for blue light show that the refractive index of the support has little influence on the optimum thickness range of the improvement coating. The sa me observation is done with a translucent conductive substrate according to the invention.
The inventors have fou nd that in add ition to providing a h igh emission level, the use of a substrate which comprises a transparent support and an electrode is such that the optical thickness of the coating having properties for improving light transmission (120), TDi, and the geometric thickness of the meta l cond uction layer (122), TME, are linked by the following equation TME = TME_O + [ B * s i n (n*TDi/TDi_o)]/(nSuPPort)3 allows a quasi-white light to be provided when sources of red, blue and green light are used at the same time, as Figures 5 to 9 show. More particularly, as Figures 13 to 15 show, when the substrate wh ich com prises a transparent support and an electrode according to the relation TME = TME_O + [B * sin (n*TDi/TDi_o)]/(risuPPort)3 / is such that it is formed by a support with a refractive index equal to 1.5 at a wavelength of 550 nm a nd with a cond uction layer of Ag with a geometric thickness equal to 12.5 nm, the inventors have been able to determine that
for every material with a refractive index within the range of values from 2.0 to 2.3, the optimum geometric thickness of the improvement coating (120) with a va lue ranging from 45 to 95 nm surprisingly allows a quasi-white light to be obtained. The quasi-white light is preferably obtained with a geometric thickness ranging from 60.0 to 80.0 nm, more preferred from 65.0 to 75.0 nm. Thus, the simultaneous use of three light sources that emit spectra of colorimetric coordinates (0.63, 0.36) for the red light source, (0.26, 0.68) for the green light source and (0.13, 0.31) for the blue light source allows a quasi-white light to be obtained, i.e. for a coating improving light transmission with a geometric thickness of 70.0 nm and a refractive index of 2.3. The same observation is done with a translucent conductive substrate according to the invention.
On the basis of Figures 5 to 7 the inventors have surprisingly found that two particular areas can be selected in the structures of substrates which comprise a transparent support and an electrode such as TME = TME_O + [ B * s i n (n*TDi/TDi_o)]/(nSupport)3 / intended for incorporation into an organic light-emitting device.
The first area of selection relates to substrates, wherein the support has a refractive index equal to 1.5 at a wavelength of 550 nm and the geometric thickness of the metal conduction layer is at least equal to 6.0 nm, preferably at least equal to 8.0 n m, more preferred at least eq ua l to 10.0 n m a nd at most eq ua l to 22.0 n m, preferably at most equal to 20.0 nm, more preferred at most eq ual to 18.0 n m, the geometric thickness of the metal conduction layer is advantageously comprised within the range of two of the preceding values, preferably within the range from 6.0 nm to 22.0 nm, more preferably from 8.0 nm to 18.0 nm, the most preferably from 10.0 nm to 18.0 nm, and wherein the geometric thickness of the coating for improving light transmission is at least equal to 50.0 nm, preferably at least equal to 60.0 nm and at most equal to 130.0 nm, preferably at most equal to 110.0 nm, more preferred at most equal to 90.0 nm, the geometric th ickness of the coati n g for i m provi ng l ig ht transmission is advantageously comprised within the ra nge of two of the preced ing values, preferably within the range from 50.0 n m to 110.0 n m, more preferably from 60.0 nm to 90.0 nm. This structure has the triple advantage of using a low-cost soda- lime-silica glass support, of using finer metal conduction layers (e.g . of Ag) combined with g reater th icknesses of the coating for improving light tra nsmission, a nd such th icknesses allow a better protection of the metal cond uction layer against possible contamination by the migration of alkaline substances coming from the soda-lime-silica glass support.
The second area of selection concerns substrates with a support with a refractive index value in the range of 1.4 to 1.6, wherein the geometric thickness of the
metal conduction layer is at least equal to 16.0 nm, preferably at least equal to 18.0 nm, more preferred at least equal to 20.0 nm and at most equal to 29.0 nm, preferably at most equal to 27.0 nm, more preferred at most equal to 25.0 nm, the geometric thickness of the metal conduction layer is advantageously comprised within the range of two of the preceding values, preferably from 16.0 nm to 29.0 nm, more preferably from 18.0 nm to 27.0 nm, the most preferably 20.0 nm to 25.0 nm, a nd wherein the geometric thickness of the coating for improving light transmission is at least equal to 20.0 n m a nd at most eq ual to 40.0 n m . Th is structu re has the adva ntage of usi ng th icker metal conduction layers (e.g . of silver), the use of a th ick meta l cond uction layer enabling better conduction to be achieved.
The inventors have su rprisingly found that the same observation is also done with the translucent conductive substrate according to the invention.
Figure 19 shows the development of the simulated reflection, expressed in D65 at 2° in accordance with European standard EN 410, of a substrate comprising a support having a refractive index equal to 1.5 at a wavelength eq ual to 550 n m as a function of the geometric thickness of the coating for improving light transmission and of the geometric th ickness of the meta l conduction layer of Ag, wherein a bove the conduction layer the substrate also comprises a sacrificial layer of TiOx that has a geometric thickness equal to 3.0 nm and an insertion layer of ZnxSnyOz (where x + y > 3 and z ≤ 6) that has a geometric thickness equal to 14.7 nm, wherein the insertion layer is coated with a n orga n ic med i u m with a refractive i ndex eq ua l to 1.7 at a wavelength of 550 nm. The sine curves appearing in the form of thicker lines indicate extreme values in the area selected by the equation TME = TME_O + [ B * s i n (n*TD1/TD1_o)]/(nsupport)3. Figure 20 shows the development of the luminance of the organic light- emitting device incorporating a substrate comprising a support with a refractive index of 1.5 at a wavelength of 550 n m a nd a metal conduction layer having a geometric thickness of 12.5 nm as a function of the geometric thicknesses of the insertion layer (Ein) and the first organic layer of the electrode (Eorg) for a green light. This calculation was cond ucted not by ta ki ng into accou nt a l u minous rad iation limited to a si ng le wavelength, but by taking into account the real spectrum of wavelengths, as shown in Figure 11. The luminance was also calculated using the program SETFOS, version 3. This luminance is expressed as arbitrary un it. The inventors have su rprisingly fou nd that two areas characterised by the luminance maxima were observed :
• the first area correspond ing to the equation : Eorg = A - Ein, where A is a constant having a value in the range of 5.0 to 75.0 nm, preferably from 20.0 to 60.0 nm, more preferred from 30.0 to 45.0 nm.
• the second area corresponding to the equation : Eorg = C - Ein, where C is a constant having a value in the range of 150.0 to 250.0 nm, preferably from
160.0 to 225.0 nm, more preferred from 75.0 to 205.0 nm.
The inventors have found that the equations Eorg = A - Ein or Eorg = C - Ein surprisingly allow the geometric thickness of the first organ ic layer of the organic light-emitting devices to be used to optimise the optica l pa ra meters (geometric th ickness and refractive index) of the insertion layer and therefore to optimise the amount of lig ht transmitted while retaining a th ickness of the insertion layer that is compatible with the electrical properties that ena ble h ig h ig n ition voltages, i .e. respectively for a first and a second luminance maximum, to be avoided.
The translucent conductive substrate according to the invention, its mode of execution as well as the organic light-emitting device containing it will now be characterised on the basis of practical examples described and collated in the following Tables I, II, III, IV, V and VI. These exa m ples a re i n no way restrictive of the invention.
The organic light-emitting devices that emit a green-coloured monochromic radiation whose performances are shown in Tables I, II, II, IV, VI and VI have the following organic structure, starting from the translucent conductive substrate (1):
• a layer of N,N'-bis(l-naphthyl)-N,N'-diphenyl-l, -biphenyl-4,4'-diamine, abbreviated to alpha-NPD, · a layer of 1,4,7-triazacyclononane-N, N', N"-triacetate (abbreviated to TCTA)
+ tris[2-(2-pyridinyl)phenyl-C,N] iridium, abbreviated to Ir(ppy)3,
• a layer of 4,7-diphenyl-l,10-phenanthroline (abbreviated to BPhen),
• a layer of LiF,
• an upper reflective electrode composed of at least one metal. According to a preferred embodiment, the metal of the upper reflective electrode consists of at least Ag. According to an alternative embodiment, the metal of the upper reflective electrode consists of at least Al.
The translucent conductive substrates used in the present examples are manufactured as follows:
The glass substrate is a clear soda lime glass made by AGC with a thickness of 1.60 mm. The scattering layer is deposited on the glass support as follow: the glass frit material was mixed so that the glass composition may become, in mol% based on oxides, 22.7 mol% of P205, 14.9 mol% of Bi203, 15.7 mol% of Nb205, 20.6 mol% of ZnO, 11.8 mol% of B203, 5.0 mol% of Li20 and 9.3 mol% of W03. After that, the prepa red frit materia l was dissolved spending 90 min utes at 1050°C in electric furnace, and after holding for 60 minutes at 950°C, the glass flakes was obtained by a roll cast. The glass transition temperature of this glass is 475°C, its deformation point is 525°C, the thermal expansion coefficient is 72x lO-7(l/°C) (average value of from 50 to 300°C). The measurement was done at 5°C/min by the thermal expansion method by using the thermal analysis equipment (Made by the Bruker company, the brand name: TD5000SA). Moreover, the refractive index nF at F-line (486.13n m) is 2.00, the refractive index nd at d-line (587.56nm) is 1.98, the refractive index nC at C-line (656.27nm) is 1.97. The refractive index meter (Made by Shimadzu Device corporation, the brand name: KPR-2000) is used.
After crush i ng the ma n ufactu red g lass fla kes for two hou rs i n the planetary mill made of zirconia, the crushed glass flakes were put through a sieve to obtain the glass frits. At this time, the particle size distribution of the g lass flakes is that D50 was 2.15μιτι, Di0 was 0.50μιτι, and D90 was 9.72μιτι. D50=2,15um means that 50% of the particles have a particle size lower than or equal to 2.15 μιτι, Di0=0.50 μιτι means that 10% of the particles have a particle size lower than or equal to 0.5 μιτι and Ο90 = 9.72μιτι means that 90% of the particles have a particles size lower than or equal to 9.72μιτι. The particles size is determined by TEM (Transmission Electron Microscope) pictures. Next, the obtained glass frits 35g were mixed with the organic vehicle which was dissolved by - -terpineol and ethyl cellulose to obtain glass paste. The glass paste was uniformly printed on the glass support in the circle where the diameter was 10 mm, causing an after-firing thickness to be 14μιτι. After drying this substrate for 30 minutes at 150°C, the substrate was returned to room temperature once. The temperature rose up to 450°C by taking 45 minutes. Then, the su bstrate was held for 30 min utes at 450°C to be fired. Afterwards, the temperature rose up to 580°C by taking 13 minutes, held for 30 minutes at 580°C and was done up to the room temperature by taking three hours. Therefore, the scattering layer was formed on the glass support. The layers forming the electrode (12) of the examples of translucent conductive substrate (1) according to the invention have been deposited by magnetron sputtering onto a clear glass support (10) with a thickness of 1.60 mm.
The deposition conditions for each of the layers are as follows:
• the Ti02-based layers are deposited using a titanium target at a pressure of 0.5 Pa in an Ar/02 atmosphere,
• the ZnxSnyOz-based layers are deposited using a target of ZnSn alloy at a pressure of 0.5 Pa in an Ar/02 atmosphere,
• the Ag-based layers are deposited using an Ag target at a pressure of 0.5 Pa in an Ar atmosphere,
• the Ti-based layers are deposited using a Ti target at a pressure of 0.5 Pa in an Ar atmosphere and can be partially oxidised by the subsequent Ar/02 plasma,
• the layers for homogenizing surface electrical properties based on Ti nitride are deposited using a Ti target at a pressure of 0.5 Pa in an 80/20 Ar/N2 atmosphere.
Compare to an ITO electrode, the deposition conditions require a lower temperature which reduces the risk of an alkaline migration from the support of the scattering layer.
Examples:
Table I shows four columns with examples of translucent conductive substrates (1) not in conformity with the invention as well as the results of measurements of electrical and optical performance obtained by means of the organic light-emitting device in which these substrates are incorporated. The general structure of the organic light-emitting device has been described above (p. 46, I. 19 to p. 48, I. 16). Example I.1R is an ITO electrode. Example I.2R is an ITO with a scattering layer. Example I.3R is a translucent conductive substrate without scattering layer and having an electrode that is not optimised, since the thickness of the improvement coating (120) has not been optimised and therefore lies outside the optical thickness range complying with equation: TME = TME_O + [B * sin (n*TDi/TDi_o)]/(nSupport)3- Example I.4R is a translucent conductive substrate without scattering layer and comprising an electrode wherein the thickness of the improvement coating (120) has been optimised and therefore lies inside the optical thickness range complying with equation: TME = TME_O + [B * sin (n*TDi/TDi_o)]/(nSupport)3- In examples I.3R and I.4R, the improvement coating (120) has a barrier layer (1200), which is merged with a layer for improving light transmission (1201) and this layer is covered by a crystallisation layer (1202).
Moreover, the crystallisation (1202) and insertion (123) layers are of the sa me natu re. These layers are made of ZnxSnyOz (where x + y > 3 and z ≤ 6), the ZnxSnyOz preferably comprising at most 95% by weight of zinc, the percentage by weight of zinc being expressed in relation to the total weight of the metals present in the layer based on an architectural low-emission stacking structure having a cond uction layer of Ag (122).
Table I :
Examples 1.1 R I.2R I.3R I.4R
Scattering layer (nm) (11) - 50 - -
Electrode (12) Nature/Thickness(nm)
Coating Layers
Improvement Barrier (1200) ITO/ ITO/ Ti02/ 20.0 Ti02/ 65.0 (120) 90.0 90.0
Improvement
(1201)
Crystallisation ZnxSnyOz / ZnxSnyOz / 5.0 (1202) 5.0
Conduction layer (112) Ag/ 12.5 Ag/12.5
Sacrificial layer (111 b) Ti/ 2.5 Ti/ 2.5
Insertion layer (113) ZnxSnyOz ZnxSnyOz /7.0
/7.0
Homogenisation layer (114) Ti nitride / Ti nitride /
1.5 1.5
Resistance (Ω/D) 35.00 35.00 4.00 3.78
OCE 1.0 1.5 1.0 1.2
Δχ (with scattering layer) - 0.00140 - -
Δχ (without scattering layer) 0.01310 - 0.20000 0.17000
Ay (with scattering layer) - 0.00245 - -
Ay(without scattering layer) 0.02250 - 0.20000 0.16000
The support (10) is a clear glass with a geometric thickness equal to 1.60
Ta ble II shows two colu mns with exa mples of translucent conductive substrates (1) according to the invention and having different types of electrodes as well as the electrical a nd optical performance of the organ ic light-emitting device in which these are incorporated. Example II.5 is a translucent conductive substrate with a scattering layer and comprising an electrode that is not optimised, since the thickness of the improvement coating (120) lies outside the optical th ickness range complying with equation : TME = TME_O + [B * sin (n*TDi/TDi_o)]/(nSupport)3- Example II.6 is a translucent conductive substrate with a scattering layer and having an electrode that is optimised for an OLED, since the thickness of the improvement coating (120) lies inside the optical thickness range complying with equation : TME = TME_O + [ B * s i n (n*TDi/TDi_o)]/(nSupport)3- In the examples II.5 and II.6, the improvement coating (120) has a barrier layer (1200) which is covered by a crystallisation layer (1202). Moreover, the crysta llisation (1202) a nd insertion (123) layers are of the same natu re. These layers are made of ZnxSnyOz (where x + y > 3 and z ≤ 6), the ZnxSnyOz preferably comprising at most 95% by weight of zinc, the percentage by weight of zinc being expressed in relation to the total weight of the metals present in the layer.
Table II:
Examples II.5 II.6
Scattering layer (μιτι) (11) 50 50
Electrode (12) Nature/Thickness(nm)
Coating Layers
Improvement Barrier (1200) Ti02/ 20.0 Ti02/ 60.0
(120)
Improvement
(1201)
Crystallisation ZnxSnyOz / 5.0 ZnxSnyOz / 10.0
(1202)
Conduction layer (122) Ag/ 12.5 Ag/12.5
Sacrificial layer (121b) Ti/ 2.5 Ti/ 2.0
Insertion layer (123) ZnxSnyOz /7.0 ZnxSnyOz /7.0
Homogenisation layer (124) Ti nitride / 1.5 Ti nitride / 1.5
Δχ (with scattering layer) 0.02100 0.02400
Ay (with scattering layer) 0.03300 0.01400
OCE 1.1 1.9
The support (10) is a clear glass with a geometric thickness equal to 1.60
The comparison of examples II.5 and II.6 with the comparative examples MR, I.2R, I.3R a nd I.4R clearly shows the advantages provided by the translucent conductive substrate according to the invention in terms of optical performance.
The out-cou pl ing coefficient efficiency (OCE) is the factor that defi nes the a mou nt of l ig ht that ca n be extracted com pa red to that of a reference . OCE is calculated in regards to the reference represented in example I. IR. The OCE values are determined as follows: · The luminance of each OLED incorporating the substrate of the example I. IR,
1.2 R, I.3R, I.4R, II.5 and II.6 were measured at an angle Θ = 0°. The voltage applied on each sample is the once required to obtain a current intensity of 6 mA.
• The OCE were obtained by dividing the luminance values obtained by the value of the luminance measured for example I. IR.
The optical measurement were performed thanks to a multi-channel spectroscope (trade name: C10027) manufactured by Hamamatsu Photonics K.K.. For the defin ition of the angle, the angle between a normal line direction of the element and a d irection extending from the element to the spectroscope was defined as the measurement angle Θ (fig . 21).
Surprisingly, the inventors found that small variation in the structure of the mu ltilayered translucent conductive su bstrate have a significant influence on the OCE. This effect on the OCE is found despite the fact that the refractive index of the first layer of the multilayer electrode is comparable to that of the scattering layer. The
comparison of example I.3R and II.5 but also of examples I.4R and II.6 shows the effect of the scattering layer on the OCE. In the case of an electrode stacking structure such as describes in examples I.3R and II.5, the incorporation of the scattering layer leads to an increase of 10% of the OCE. In the case of an electrode stacking structure such as describe in example I.4R and II.6, the incorporation of the scattering layer leads to an increase of the OCE of 58%.
The inventors have surprisingly found as shows by the comparison of example I.3R and II.6 that an increase of around 90% of the OCE is obtained when a translucent conductive substrate according to the invention is used . In addition, the comparison of the OCE obtained shows a synergetic effect of the scattering layer and the optimized electrode on the OCE. If the effect would be simply cumulative an increase of 30% of the OCE would be obtained : 10% thanks to the scattering layer used and 20% thanks to the optimized electrode. Furthermore, the comparison of the OCE clearly shows that the amount of light emitted by the example II.6 is 90% higher than the amount of light emitted by the example I.1R which represents a conventional substrate for OLED (ITO electrode on glass)
Finally, the comparison of the values Ax(with scatteri ng layer), Ax(without scattering layer), Ay(with scattering layer), Ay(without scattering layer) shows the positive effect of the scattering layer on the angular dependency, x and y representing the chromaticity coordinates in the CIE (x,y) chromaticity diagram. The terms "with scattering layer" and "without scattering layer" are respectively linked to a translucent conductive substrate with and without scattering layer.
Where:
Ax(withoutscatteringlayer) = x^°° - -X^n70°
0°— 70° 0°— 70°
-^max represents the highest x value measured between 0° and 70°; represents the lowest x value measured between 0° and 70°
Ax(withscatte ringlayer) = ^~70° - -^n™"
0°— 70° 0°-70°
• max represents the highest x value measured between 0° and 70°; represents the lowest x value measured between 0° and 70° Ay(withoutsca tteringlayer) = j ~ x 70° - ^70°
0°-70°
^max represents the highest y value measured between 0° and 70°;
0°-70°
y^a represents the lowest y value measured between 0° and 70°
0°-70°
^max represents the highest x value measured between 0° and 70°;
0°— 70°
y^a represents the lowest y value measured between 0° and 70°
The optical measurement were performed thanks to a multichannel spectroscope (trade name: C10027) manufactured by Hamamatsu Photonics K.K.. For the definition of the angle, the angle between a normal line direction of the element and a direction extending from the element to the spectroscope was defined as the measurement angle Θ (fig.21). The measurement was made while rotating the OLED to the spectroscope, thereby measuring the angular dependency of light emitting colour
The value x and y are measured as follows:
The luminance of each OLED incorporating the substrate of the example MR, I.2R, I.3R, I.4R, II.5 and II.6 were measured at different angles from Θ = 0° to 70°. The voltage applied on each sample is the one required to obtain a current intensity of 6 mA.
Finally, from an electrical point of view, the resistance value (around 4 Q n) obtained for a translucent conductive substrate according to the invention are lower than the resistance value obtained with a classical ITO substrate (around 35 Q/n) Table III shows three columns with examples of translucent conductive substrates according to the invention comprising a scattering layer and having different types of electrodes (numbers of layers, chemical nature and thickness of layers) and the measurement results of resistance expressed in Ω/D. The general structure of the organic light-emitting device has been described above (p. 46, I. 19 to p. 48, I. 16). Example III.1 is a translucent conductive substrate having an electrode comprising a conduction layer of Ag (122), a layer for homogenizing surface electrical properties (124), an improvement coating wherein the thickness of the improvement coating (120) has not been optimised, since the thickness of the improvement coating (120) lies outside the optical thickness range complying with equation: TME = TME_O + [B * sin (n*TDi/TDi_o)]/(nSupport)3- In this example, the improvement coating (120) comprises a barrier layer (1200), which is merged with an improvement layer (1201) and this layer is covered by a crystallisation layer (1202). Moreover, the crystallisation (1202) and
insertion (123) layers a re of the sa me natu re. These layers a re made of ZnxSnyOz (where x + y > 3 and z≤ 6), the ZnxSnyOz comprising at most 95% by weight of zinc, the percentage by weight of zinc being expressed in relation to the total weight of the metals present in the layer. Examples III.2 and III.3 illustrate translucent conductive substrates in conformity with the invention. In these examples, the improvement coating (120) has an optical thickness complying with equation TME = TME_O + [B * sin (n*TDi/TDi_o)]/(nSupport)3 and having a barrier layer (1200), wh ich is merged with a n improvement layer (1201) a nd this layer is covered by a crysta llisation layer (1102). Moreover, the crystallisation (1202) and insertion (124) layers are of the same nature. These layers are made of ZnxSnyOz (where x + y > 3 and z ≤ 6), the ZnxSnyOz preferably comprising at most 95% by weight of zinc, the percentage by weight of zinc being expressed in relation to the tota l weig ht of the metals present in the layer. Example III.3 illustrates a translucent conductive su bstrate in accordance with the invention having an electrode that is optimised with respect to the geometric thickness of the crystallisation layer (1102).
Table III
Examples III.l III.2 III.3
Scattering layer (μιτι) (11) 50 50 50
Coating Layers Nature/ Nature/ Nature/ thickness thickness thickness
(nm) (nm) (nm)
Improvement Barrier (1200) Ti02/ 20.0 Ti02/ 65.0 Ti02 / 60.0
(120) Improvement (1201)
Crystallisation (1202) ZnxSnyOz / ZnxSnyOz / ZnxSnyOz /10.0
5.0 5.0
Conduction layer (122) Ag / 12.5 Ag / 12.5 Ag / 12.5
Sacrificial layer (121b) Ti / 2.5 Ti / 2.5 Ti / 2.5
Insertion layer (123) ZnxSnyOz / ZnxSnyOz / ZnxSnyOz/ 7.0
7.0 7.0
Homogenisation layer ( 124) Ti nitride / Ti nitride / Ti nitride/ 1.5
1.5 1.5
Resistance (Ω/D) 3.78 4.09 3.91
The support ( 10) is a clear glass with a geometric thickness equal to 1.60 mm.
As described above, the translucent conductive substrate according to the invention has an electrode that has at least one additional insertion layer ( 123) . The fu nction of th is insertion layer ( 123) is to form pa rt of a n optica l cavity that enables the metal cond uction layer to become transparent. In fact, it is known to a person skilled in the art optimising low-emission multilayer coatings, for example, that the use of an insertion layer with a geometric thickness of at least 15.0 nm is necessary to make the conduction layer transparent. On the other hand, no conductivity condition is imposed to obtain optical transparency values compatible with architectural applications. The layers developed for architectural application cannot be used directly for optoelectron ic a pplications, si nce they genera l ly conta in d ielectric compou nds and/or poorly conductive compounds.
The inventors have surprisingly determined that the geometric thickness of the insertion layer (Ein) ( 123) is such that, firstly, its ohmic th ickness is at most equal to 1012 ohm, preferably at most equal to 104 ohm, wherein the ohmic thickness is equal to the relation between the resistivity of the material forming the insertion layer (■)/ on the one hand, and the geometric thickness of this same layer (I), on the other; and secondly, the geometric thickness of the insertion layer ( 123) is l i n ked to the geometric thickness of the first organic layer of the organic light-emitting device (Eorg), the term "first organic layer" denoting all the organic layers disposed between the insertion layer ( 123) and the organic light-emitting layer. The inventors have th us surprisingly found, as indicated i n Fig u re 20 , that two a reas cha racterised by the luminance maxima were observed : the first area corresponding to the equation : Eorg = A - Ein, where A is a constant having a value in the range of 5.0 to 75.0 nm, preferably from 20.0 to 60.0 nm, more preferred from 30.0 to 45.0 nm. the second area corresponding to the equation : Eorg = C - Ein, where C is a constant having a value in the range of 150.0 to 250.0 nm, preferably from 160.0 to 225.0 nm, more preferred from 75.0 to 205.0 nm.
The inventors have thus found that the equations Eorg = A - Ein or Eorg = C - Ein allow the geometric thickness of the first organic layer of the organic light- emitting device to be used to optimise the optical parameters (geometric thickness and refractive index) of the insertion layer and therefore to optimise the amount of light transmitted while retaining a thickness of the insertion layer that is compatible with the electrical properties that enable high ignition voltages, i.e. respectively for a first and a second luminance maximum, to be avoided.
Moreover, the use of a dielectric, i.e. poorly conductive, layer for contact between the conduction layer and the organic portion of the organic light-emitting device runs counter to the customarily accepted knowledge of a skilled person who has to manufacture organic light-emitting devices. The inventors have surprisingly found that the use of a dielectric, i.e. poorly conductive, material does not have to be excluded for the formation of the insertion layer (123). However, a conductive material is preferred. In fact, if the insertion layer has too high an ohmic thickness, the voltages of use increase considerably, as shown in Table IV.
Table IV shows two columns with examples of translucent conductive substrates according to the invention and having different types of electrodes (numbers of layers, chemical nature and thickness of layers) as well as the results of measurements of electrical performance obtained by means of the organic light-emitting device in which these substrates are incorporated. The general structure of the organic light-emitting device has been described above (p. 46, I. 19 to p. 48, I. 16). Example IV.1 is a translucent conductive substrate comprising an electrode based on a structure having a conduction layer of Ag (122), the electrode is not optimised. The electrode of the example IV.1 has a homogenisation layer (124) and a coating for improving light transmission (120), of which the optical thickness has not been optimised and therefore lies outside the thickness range complying with equation TME = TME_O + [B * sin (n*TDi/TDi_o)]/(nSupport)3- In example IV.1 the improvement coating (120) comprises a barrier layer (1200), which is merged with an improvement layer (1201) and this layer is covered by a crystallisation layer (1202). Moreover, the crystallisation (1202) and insertion (123) layers are of the same nature. These layers are made of ZnxSnyOz (where x + y > 3 and z ≤ 6), the ZnxSnyOz comprising at most 95% by weight of zinc, the percentage by weight of zinc being expressed in relation to the total weight of the metals present in the layer. Moreover, example IV.1 also shows an insertion layer (123) with a geometric thickness that has not been optimised. Example IV.2 illustrates an optimised electrode, the improvement coating (120) has an optical thickness complying with equation TME = TME_O + [B * sin (n*TDi/TDi_o)]/(nSupport)3 / the improvement coating has a barrier layer (1200), which is merged with an improvement layer (1201) and this
layer is covered by a crystallisation layer (1202). Moreover, the crystallisation (1202) and insertion (124) layers are of the same nature. These layers are made of ZnxSnyOz (where x + y > 3 and z ≤ 6), the ZnxSnyOz preferably comprising at most 95% by weight of zinc, the percentage by weight of zinc being expressed in relation to the total weight of the metals present in the layer. It is evident that the electrical properties of example IV.2 are appreciably higher than those shown in example IV.1.
Table IV:
The support (10) is a clear glass with a geometric thickness equal to 1.60 mm.
Finally, Table V shows that with a constant geometric thickness of the insertion layer, it is possible to reduce the voltages of use, decreasing the resistivity of this layer. In fact, Table V shows three columns with examples of translucent
conductive substrates, which are in accordance with the invention but differ from one another with respect to the natu re of the chemica l compou nd forming the insertion layer, as well as the resu lts of measu rements of electrica l a nd optica l performa nce obtained by means of the organic light-emitting device in which these electrodes are incorporated. The general structure of the organic light-emitti ng device has been described above (p. 46, I. 19 to p. 48, I. 16). Example V. l illustrates a translucent conductive substrate according to the invention that has an electrode with an insertion layer com p risi ng a con d uctive layer made of zi nc oxide doped w ith a l u m i n i u m (resistivity of ZnO:AI : 10"4 Q*cm). Example V.2 illustrates a translucent conductive substrate according to the invention that has an electrode with an insertion layer comprising a poorly conductive layer made of ZnxSnyOz (where x + y > 3 and z ≤ 6), the ZnxSnyOz preferably comprising at most 95% by weight of zinc, the percentage by weight of zinc being expressed in relation to the total weight of the metals present in the layer (resistivity of ZnxSnyOz : 10"2 Q*cm). Example V.3 illustrates a translucent conductive substrate according to the invention that has an electrode with an insertion layer comprising a dielectric layer of titanium dioxide (resistivity of Ti02 : 70 104 Q*cm).
It is evident that to reach a cu rrent level of 100 mA, the voltage to be applied is lower in the case of a conductive insertion layer with a layer made from a conductive material than in the case of a layer made from a dielectric material.
Table V:
Examples V. l V.2 V.3
Scattering layer (11) 50 μιτι 50 μιτι 50 μιτι
Coating Layers Nature/ Nature/ Nature/ thickness thickness thickness
(nm) (nm) (nm)
Improvement Barrier (1200) Ti02/ 65.0 Ti02/ 65.0 Ti02/ 65.0
(120) Improvement (1201)
Crystallisation (1202) ZnxSnyOz/ ZnxSnyOz/ ZnxSnyOz/
5.0 5.0 5.0
Conduction layer (122) Ag / 12.5 Ag / 12.5 Ag / 12.5
Sacrificial layer (121b) Ti / 2.5 Ti / 2.5 Ti / 2.5
Insertion layer (123) ZnO:AI / 7.0 ZnxSnyOz / Ti02 / 7.0
7.0
Homogenisation layer (124) Ti n itride / Ti n itride / Ti nitride /
1.5 1.5 1.5
Electrical performance V at 100 mA/cm2 2.98 3.55 3.98
The support (10) is a clear glass with a geometric thickness equal to 1.60
Ta ble VI shows organ ic lig ht-emitting devices that emit a quasi-white light. The general structure of the organic light-emitting device that emit a quasi-white light whose performances are shown in Table VI have the following structure, starting with the translucent conductive substrate:
• a layer of N, N, N',N"-tetrakis(4-methoxyphenyl)-benzidine (abbreviated to MeO- TPD) doped with 4 mole % of NPD-2
• a layer of N,N'-di(naphthalen-l-yl)-N-N'-diphenyl-benzidine (abbreviated to NPB), · a stacking structure of emission layers formed from 4,4',4"-tris(N-carbazolyl)- triphenylamine (abbreviated to T TA) and from 2,2',2"(l,3,5-benzenetriyl) tris(l-phenyl- lH-benzidimazole) (abbreviated to TBPi) partially doped with iridium-bis-(4,6- difluorophenyl-pyridinato-N,C2)-picolinate (abbreviated to FirPic), tris[2-(2- pyridinyl)phenyl-C,N] iridium (abbreviated to Ir(ppy)3) and iridium (III)bis(2- methyldibenzo[f,h]quinoxaline) (acetylacetonate) (abbreviated to Ir5MDQ)2 (acac),
• a layer of 2,2',2"(l,3,5-benzenetriyl) tris-(l-phenyl-lH-benzimidazole) (abbreviated to TBPi),
• a layer of 4,7-diphenyl-l,10-phenanthroline doped with Cs,
• an upper reflective electrode composed of at least one metal. According to a preferred embodiment, the metal of the upper reflective electrode consists of at least Ag. According to an alternative embodiment, the metal of the upper reflective electrode consists of at least Al.
The acronyms used to denote the compounds used are well known to the person skilled in the art. The structure of the organic layers used is described in page 237 in section "Methods Summary" of the article by Reineke et Coll. in Nature, 2009, vol. 459, pp. 234 to 238.
The scattering layer (11) and the electrode (12) of the examples of translucent conductive substrate (1) according to the invention have been deposited following the conditions describe here above (p. 47, I. 1 to p. 48, I. 16). Example VI.1 is a translucent conductive comprising an electrode based on a stacking structure having a conduction layer of Ag. Example VI.1 is a translucent conductive substrate according to the invention that comprises an electrode that is not optimised for an OLED having a homogenisation layer (124) and wherein the thickness of the improvement coating (120) lies outside the thickness range complying with equation:
TME = TME_o + [B * sin (n*TDi/TDi_o)]/(nSupport)3
In example VI.1 the improvement coating (120) comprises a barrier layer (1200), which is merged with an improvement layer (1201) and this layer is covered by a crystallisation layer (1202). Moreover, the crystallisation (1202) and insertion (123) layers are of the same nature. These layers are made of ZnxSnyOz (where x + y > 3 and z ≤ 6), the ZnxSnyOz comprising at most 95% by weight of zinc, the percentage by weight of zinc being expressed in relation to the total weight of the metals present in the layer. Examples VI.2 and VI.3 show examples wherein the improvement coating (2) has an optical thickness complying with equation TME = TME_O + [B * sin (n*TDi/TDi_o)]/(nSupport)3 and this has a barrier layer (1200), which is merged with an improvement layer (1201) and this layer is covered by a crystallisation layer (1202). Moreover, the crystallisation (1202) and insertion (124) layers are of the same nature. These layers are made of ZnxSnyOz (where x + y > 3 and z ≤ 6), the ZnxSnyOz preferably comprising at most 95% by weight of zinc, the percentage by weight of zinc being expressed in relation to the total weight of the metals present in the layer. Moreover, example VI.2 more particularly illustrates a translucent conductive substrate having a fine metal layer and having a more significant thickness of coating for improving light transmission properties. The advantage of such thickness of the improvement coating is that:
• it allows, on the one hand, better protection of the metal conduction layer against any contamination of said layer by migration of pollutants (e.g.: alkaline substances) coming from the support or the scattering layer,
• on the other hand, it allows less precious metal to be used for the formation of the metal conduction layer.
Example VI.3 illustrates a translucent conductive substrate having a thick silver layer that allows a conduction layer with a low resistance to be obtained. The
comparison of the properties obtained for devices emitting quasi-wh ite l ig ht incorporating a translucent conductive substrate according to examples VI.1, VI.2 and VI.3 demonstrates that:
• the service lives of the devices comprisi ng a su bstrate accord i ng to the invention are longer compared to example VI.1, but also compared to a translucent conductive substrate consisting of an identical support (10) and with an electrode of ITO disposed on top of it that has a geometric thickness equal to 90 nm, the service life of which amounts to 162 hours (result not established in Table VI); · the surface resistance (Ω/D) of example VI.3 having a thick conduction layer is at least half as low as the surface resistance (Ω/D) of examples VI.2 and VI.1, and this property provides the possibility of forming devices of larger dimensions without using any conduction reinforcement such as a metal grid, for example. Table VI
Examples VI.1 VI.2 VI.3
Scattering layer (11) 50 μιτι 50 μιτι 50 μιτι
Coating Layers Nature/ Nature/ Nature/ thickness thickness thickness
(nm) (nm) (nm)
Improvement Barrier (1200) Ti02/ 20.0 Ti02/ 65.0 Ti02/ 20.0
(120) Improvement (1201)
Crystallisation (1202) ZnxSnyOz / ZnxSnyOz / ZnxSnyOz /
5.0 5.0 5.0
Conduction layer (122) Ag / 12.5 Ag / 12.5 Ag / 23.0
Sacrificial layer (121b) Ti / 2.5 Ti / 2.5 Ti / 2.5
Insertion layer (123) ZnxSnyOz / ZnxSnyOz / ZnxSnyOz /
7.0 7.0 7.0
Homogenisation layer ( 124) Ti n itride / Ti n itride / Ti nitride /
1.5 1.5 1.5
Resistance (Ω/D) 3.78 4.09 1.80
Electrical performance V at 2 mA/cm2 9.7- 10.4 9.2 - 9.4 10.1 -10.5
Service life (in hours) 166 625 739 measured at 30 mA/cm2
The support ( 10) is a clear glass with a geometric thickness equal to 1.60 mm.
The electrical performance levels are measured by applied voltages (V) to obtain a current of 2 mA/cm2.
Table VII shows organic light-emitting devices that emit a quasi-white light. The general structure of the organic light-emitting device that emit a quasi-wh ite light whose performances are shown in Table VII have the following organ ic structu re, starting from the translucent conductive substrate:
• a layer of N,N'-bis(l-naphthyl)-N,N'-diphenyl-l, -biphenyl-4,4'-diamine, abbreviated to alpha-NPD, · a layer of NPD + 5,6, 11 , 12-tetraphenylnaphthacene abbreviated rubrene ,
• a layer of 2-methyl-9, 10-di(2-naphthyl) anthracene, abbreviated to MADN + p-bis_p-/V,/V-di-phenyl-aminostyryl benzene, abbreviated to DSA ,
• a layer of tris(8-hydroxyquinoline) aluminium, abbreviated to AIQ3,
• a layer of LiF, · the upper reflective electrode is also composed of at least one meta l .
According to a preferred embodiment, the metal of the upper reflective electrode consists of at least Ag. According to an alternative embodiment, the metal of the upper reflective electrode consists of at least Al.
The scattering layer (11) a nd the electrode (12) of the examples of tra nslucent conductive substrate (1 ) accord ing to the invention have been deposited following the conditions describe here above (p. 47, I . 1 to p. 48, I . 16), said scattering layer having, in example VII.2, th e sa me com position as th e com position u sed i n th e previous examples but comprising an additional amount of 15 vol .% of alumina particles having 3 μιτι in diameter in examples VII.1 and VII.3. Moreover, the layers based on TiOx and ZnO:AI are respectively deposited using a TiOx ceramic target at a pressu re of 0.5 Pa in an Ar/02 atmosphere and using a ZnO:AI cera mic target in an Ar/02 atmosphere, a weak percentage 02 being introduced (0-0,7 %), at a pressure of 0.5 Pa . Examples VII.1 and VII.2 are translucent conductive substrates comprising an electrode based on a stacking structure having a cond uction layer of Ag . Examples VII.1 and VII.2 are translucent conductive substrates according to the invention that comprise an electrode that is not optimised for a n OLED having a homogenisation layer (124) and wherein the thickness of the improvement coating ( 120) lies outside the th ickness range complying with equation :
TME = TME_o + [B * sin (n*TDi/TDi_o)]/(nSupport)3
In example VII.1, the i m provement coati ng ( 120) com prises a ba rrier layer
(1200) , which is merged with a n improvement layer (1201) a nd th is layer is covered by a crystallisation layer (1202). Moreover, the crystallisation (1202) a nd insertion (123) layers are conductive layers of the same nature. These layers are made of zinc oxide doped with aluminium (resistivity of ZnO:AI : 10"4 Q*cm). In example VII. 2, the improvement coating (120) comprises a barrier layer (1200), a n i mprovement layer
(1201) and a crystallization layer (1202) which are merged and made of ZnxSnyOz (where x + y > 3 and z ≤ 6), the ZnxSnyOz prefera bly comprisi ng at most 95% by weight of zinc, the percentage by weight of zinc being expressed in relation to the total weight of the metals present in the layer. Example VI.3 shows an example wherein the improvement coating (120) has an optical thickness complying with equation TME = TME_O + [ B * si n ( n *TDi/TDi_o)]/(nSupport)3 and this improvement coating (120) has a barrier layer (1200), which is merged with an im provement layer ( 1201 ) a nd sa id improvement layer (1201) is covered by a crystal lisation layer (1202). Moreover, the crystallisation (1202) and insertion (124) layers are of the same nature. These layers are made of zinc oxide doped with aluminium (resistivity of ZnO:AI : 10"4 Q*cm). The sacrificial layer (121 b) is made of TiOx, said TiOx being a titan iu m oxide fu lly or partially oxidized .
Table VII
VII. l VII.2 VII.3
Examples
Scattering layer (11) 25 μιτι(1) 25 μιτι 25 μιτι(1)
Coating Layers Nature/ Nature/ Nature/ thickness thickness thickness
(nm) (nm) (nm)
Improvement Barrier (1200) Ti02/ 19.0 ZnxSnyOz/ Ti02/ 60.0
25.0
(120) Improvement (1201)
Crystallisation (1202) Z n O : A I / ZnO:AI/ ZnO:AI/ 10.0
4.0 4,0
Conduction layer (122) Ag / 9.45 Ag/9,0 Ag / 14.35
Sacrificial layer (121b) TixO / 3.0 TixO / 3.0 TixO / 3.0
Insertion layer (123) Z n O : A I / Z n O : A I / ZnO:AI / 7.0
7.0 7.0
Homogenisation layer (124) Ti nitride / Ti nitride / Ti nitride / 1.5
1.5 1.5
OCE 1.3 1.2 1.9
(1) the scattering layer comprises an additional amount of 15 vol.% of alumina particles having 3 μιτι in diameter.
The out-coupling coefficient efficiency (OCE) is the factor that defines the amount of light that can be extracted compared to that of a reference. OCE is calculated in regards to the reference represented in example I.IR. The OCE values are determined as follows:
• The luminance of each OLED incorporating the substrate of the example I.IR, VII.l, VII.
2 and VII.3 were measured at an angle Θ = 0°. The voltage applied on each sample is the once required to obtain a current intensity of 6 mA.
• The OCE were obtained by dividing the luminance values obtained by the value of the luminance measured for example I.IR.
The optical measurement were performed thanks to a multi-channel spectroscope (trade name: C10027) manufactured by Hamamatsu Photonics K.K.. For the definition of the angle, the angle between a normal line direction of the element and a direction extending from the element to the spectroscope was defined as the measurement angle Θ (fig. 21).
Claims
1. A translucent conductive substrate (1) for Organic Light Emitting Device comprising :
• a transparent support (10),
• a scattering layer (11) formed over the transparent support (10) and comprising a glass which contains a base material
(110) having a first refractive index for at least one wavelength of light to be transmitted and a plurality of scattering materials (111) dispersed in the base material (110) and having a second refractive index different from that of the base material, · a tra n spa re nt e lectrode ( 12) formed over th e scattering layer (11), said electrode (12) comprising at least one metal conduction layer (122) and at least one coating (120) having properties for improving the light transmission through said electrode, said coating (120) comprises at least one layer for improving light transmission (1201) and is located between the metal conduction layer (122) and the scattering layer (11), on which said electrode (12) is deposited.
2. Translucent conductive substrate (1) according to claiml, characterised in that the scattering materials (111) of the scattering layer (11) are selected from pores, precipitated crystals, material particles having a different chemical composition than base material (110), phase-separated glass or mixtures from at least two thereof.
3. Translucent conductive substrate (1) according to claim 2, characterised in that the material particles are selected from crystalline particles, amorphous particles or at least a mixture thereof.
4. Translucent conductive substrate (1) according to any one of the preceding claims, characterised in that the distribution of the scattering materials in the scattering layer decreases from the inside of the scattering layer (11) towards the face of the scattering layer opposite to the transparent support (10) on which said scattering layer (11) is deposited.
5. Translucent conductive su bstrate (1) accord ing to a ny one of the preceding claims, characterised in that the scattering layer comprises a first layer part and a second layer part formed on the first layer part, the said second layer part is thinner than the first layer part and the first layer part has the scattering materials much more than the second layer part.
6. Translucent conductive su bstrate (1) accord ing to a ny one of the preceding claims, characterised in that the transparent electrode formed over the scattering layer, said electrode comprising a single metal conduction layer and at least one coating having properties for improving the light transmission (120) through said electrode, wherein said coating (120) has a geometric thickness at least more than 3.0 nm and at most less than or equal to 200 nm, and said coating comprises at least one layer for improving light transmission (120) and is located between the metal conduction layer (122) and the scattering layer (11), on which said electrode is deposited, wherein the optical thickness of the coating having properties for improving the light transmission, TDi, and the geometric thickness of the metal conduction layer, TME, are linked by the equation :
TME = TME_o + [B * sin (n*TDi/TDi_o)]/(nSupport)3 where TME_O B a nd TDi_0 are consta nts with TME_O having a va lue in the ra nge of 10.0 to 25.0 n m, B havi ng a va l ue i n the ra nge of 10.0 to 16.5 n m a nd TDi 0 having a value in the range of 23.9 * nDi to 28.3 * nDi nm, with nDi representing the refractive i ndex of the coati ng for i m provi ng the l ig ht tra nsm ission at a wavelength of 550 nm and nSUpp0rt represents the refractive index of the transparent support at a wavelength of 550 nm.
7. Translucent conductive substrate according to the invention according to any one of claims 1 to 5, characterised in that the transparent electrode formed over the scattering layer, said electrode comprising a single metal conduction layer and at least one coating having properties for improving the light transmission (120) through said electrode, wherein said coating (120) has a geometric thickness at least more than 3.0 nm and at most less than or equal to 200 nm, and said coating comprises at least one layer for improving light transmission (120) and is located between the metal cond uction layer (122) and the scattering layer (11), on which said electrode is deposited, wherein the optical thickness of the coating having properties for improving the lig ht tra nsm ission ( 120), TDi, and the geometric thickness of the metal conduction layer (122), TME, are linked by the equation :
TME = TME_o + [B * sin (n*TDi/TDi_o)]/(nSs)3 where TME_O B and TDi_0 are constants with TME_O having a value in the range of 10.0 to 25.0 nm, B having a value in the range of 10.0 to 16.5 nm and TDi_o having a value in the range of 23.9 * nDi to 28.3 * nDi nm, with nDi rep resenti ng th e refractive i n dex of the coati n g for i m p rovi ng th e l ig ht transmission at a wavelength of 550 nm and nss represents the refractive index of the stacking structu re comprising the su pport a nd the scattering layer at a wavelength of 550 nm,
Where Yl
(/sup port ^scatteringlayer ,) risupport representing the refractive index of transparent su pport (10) at a wavelength of 550 nm, nscatteringiayer representing the refractive index of the scattering layer (11) at a wavelength of 550 n m, lsupport representing the geometrica l th ickness of the su pport (10) a n d ls_attenngiayer representing the geometrical thickness of the scattering layer (11).
8. Translucent conductive substrate (1) according to any one of the preceding claims, characterised in that the coating for improving light transmission (120) of the electrode (12) comprises at least one additional crystallisation layer (1202), wherein, in relation to the scattering layer (11), said crystallisation layer (1202) is the layer furthest removed from the stacking structure forming said coating (120).
9. Translucent conductive substrate (1) according to claim 8, characterised in that the geometric thickness of the crystallisation layer (1202) is at least equal to 7% of the total geometric thickness of the coating for improving light transmission (120).
10. Translucent conductive substrate (1) according to any one of the preceding claims, characterised in that the coating for improving light transmission (120) comprises at least one additional barrier layer (1200), wherein, in relation to the scattering layer (11), said barrier layer (1200) is the layer closest to the stacking structure forming said coating (120).
11. Translucent conductive substrate (1) according to any one of the preceding claims, characterised in that the electrode (12) comprises a thin layer (124) for homogenizing the surface electrical properties, which, in relation to the scattering layer (11), is located at the top of the multilayer stacking structure forming said electrode (12).
12. Translucent conductive substrate (1) according to any one of the preceding claims, characterised in that the electrode (12) comprises at least one additional insertion layer (123) located between the metal conduction layer (122) and the thin homogenisation layer (124).
13. Translucent conductive substrate (1) according to claim 12, characterised in that the geometric thickness of the insertion layer (Ein) (123) is such that its ohmic thickness is at most equal to 1012 ohm, wherein the ohmic thickness is equal to the ratio between the resistivity of the material forming the insertion layer (■), on the one hand, and the geometric thickness of this same layer (I), on the other; and the geometric thickness of the insertion layer is, moreover, linked to the geometric thickness of the first organic layer of the organic light- emitting device (Eorg), wherein the term "first organic layer" denotes all the organic layers disposed between the insertion layer and the organic light-emitting layer, by the equation : Eorg = A - Ein, where A is a constant having a value in the range of 5.0 to 75.0 nm, preferably from 20.0 to 60.0 nm, more preferred from 30.0 to 45.0 nm.
14. Translucent conductive substrate (1) according to claim 12, characterised in that the geometric thickness of the insertion layer (Ein) (123) is such that its ohmic thickness is at most equal to 1012 ohm, wherein the ohmic thickness is equal to the ratio between the resistivity of the material forming the insertion layer (■), on the one hand, and the geometric thickness of this same layer (I), on the other; and the geometric thickness of the insertion layer is, moreover, linked to the geometric thickness of the first organic layer of the organ ic lig ht-em itti ng device (Eorg), wherein the term "first organic layer" denotes all the organic layers disposed between the insertion layer and the organic light-emitting layer, by the equation : Eorg = C - Ein, where C is a constant having a value in the range of 150.0 to 250.0 nm, preferably from 160.0 to 225.0 nm, more preferred from 75.0 to 205.0 nm.
15. Translucent conductive substrate (1) according to any one of the preceding claims, characterised in that the metal conduction layer (122) comprises at least one sacrificial layer (121a and/or 121b) on at least one of its faces.
16. Translucent conductive substrate (1) according to any one of the preceding claims, characterised in that the stacking structure comprising the support (10) and the scattering layer (11), on which the electrode (12) is deposited, comprises at least one functional coating (9) on the face opposite the face, on which the scattering layer (11) is deposited.
17. Organic light-em itti n g device com prisi ng at least on e translucent conductive substrate (1) according to any one of claims 1 to 16.
18. Organic light-emitting device according to claim 17 that emits quasi-white light.
19. Method for the manufacture of the translucent conductive substrate (1) according to any one of claims 1 to 15, comprising the steps of:
• depositing of the scattering layer (11) on the support (10), · depositi ng of the coating havi ng properties for i mproving l ig ht transmission (120) on the scattering layer (11),
• depositing of the metal conduction layer (122) directly followed by the deposition of the different functional elements forming the Organic Light Emitting Device.
20. Method for the manufacture of the translucent conductive substrate (1) according to claim 11, comprising the steps of:
• depositing of the scattering layer (11) on the support (10),
• depositing of the coating (120) having properties for improving light transmission through the electrode (12), the metal conduction layer (122), the sacrificial layer (121b), the insertion layer (123) on the scattering layer (11) ,
• depositing of the homogenisation layer (124) directly followed by the deposition of the different functional elements forming the Organic Light Emitting Device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP11732463.2A EP2593979A1 (en) | 2010-07-16 | 2011-07-15 | Transluscent conductive substrate for organic light emitting devices |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP2010060304 | 2010-07-16 | ||
| EP11732463.2A EP2593979A1 (en) | 2010-07-16 | 2011-07-15 | Transluscent conductive substrate for organic light emitting devices |
| PCT/EP2011/062132 WO2012007575A1 (en) | 2010-07-16 | 2011-07-15 | Transluscent conductive substrate for organic light emitting devices |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| EP2593979A1 true EP2593979A1 (en) | 2013-05-22 |
Family
ID=48087100
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP11732463.2A Withdrawn EP2593979A1 (en) | 2010-07-16 | 2011-07-15 | Transluscent conductive substrate for organic light emitting devices |
Country Status (1)
| Country | Link |
|---|---|
| EP (1) | EP2593979A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2635091A4 (en) * | 2010-10-25 | 2015-06-10 | Asahi Glass Co Ltd | Organic el device, translucent substrate, and method for manufacturing organic el device |
-
2011
- 2011-07-15 EP EP11732463.2A patent/EP2593979A1/en not_active Withdrawn
Non-Patent Citations (1)
| Title |
|---|
| See references of WO2012007575A1 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2635091A4 (en) * | 2010-10-25 | 2015-06-10 | Asahi Glass Co Ltd | Organic el device, translucent substrate, and method for manufacturing organic el device |
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