EP2090139A2 - Electrode for an organic light-emitting device, acid etching thereof, and also organic light-emitting device incorporating it - Google Patents

Abstract

The subject of the present invention is a multilayer electrode (3), acid etching thereof and also organic light-emitting devices incorporating it. The multilayer electrode, known as a lower electrode for an organic light-emitting device (10), successively comprises: - a contact layer (31) based on a metal oxide and/or a metal nitride; a functional metallic layer (32) having intrinsic electrical conductivity properties; a thin blocking layer (32) directly on the functional layer, the layer comprising a metallic layer having a thickness less than or equal to 5 nm and/or a layer with a thickness less than or equal to 10 nm, which is based on a substoichiometric metal oxide, substoichiometric metal oxynitride or substoichiometric metal nitride; a coating comprising an overlayer based on a metal oxide (34) for adapting the work function.

Description

 ELECTRODE FOR ORGANIC ELECTROLUMINESCENT DEVICE, ACID ETCHING THEREOF, AND ORGANIC ELECTROLUMINESCENT DEVICE INCORPORATING IT

The present invention relates to a multilayer electrode for organic electroluminescent device, its acid etching and an organic electroluminescent device incorporating it.

The known organic electroluminescent systems or OLED (for "Organic Light Emitting Diodes" in English) comprise a material or a stack of organic electroluminescent materials supplied with electricity by electrodes generally in the form of two electroconductive layers flanking it.

These electroconductive layers commonly comprise a layer based on indium oxide, generally indium oxide doped with tin better known under the abbreviation ITO. ITO layers have been particularly studied. They can be easily deposited by magnetic field assisted sputtering, either from an oxide target (non-reactive sputtering), or from an indium and tin-based target (reactive sputtering in the presence of an oxygen-type oxidizing agent) of the order of 100 to 150 nm. However, this ITO layer has a number of disadvantages. Firstly, the material and the method of deposition at high temperature (350 ° C.) to improve the conductivity generate additional costs. The square resistance remains relatively high (of the order of 10 Ω / square) unless the thickness of the layers is increased beyond 150 nm, which results in a decrease in the transparency and in an increase in the roughness of the area.

Also, new electrode structures are developing. For example, JP2005-038642 discloses a flat electroluminescent screen

TFT ("thin-film transistor" in English) comprising top-emitting organic electroluminescent systems ("top emission" in English) generating respectively a red light, a green light, and a blue light, to form an active matrix .

Each organic electroluminescent device is provided with a so-called lower or rear electrode (or "bottom electrode" in English), comprising: a contact layer, for example made of ITO,

a metal layer (semi) reflecting, in particular, based on silver, aluminum, or aluminum-containing silver, having a thickness of at least 50 nm, an overlay of adaptation of the output work, by example in ITO.

The aim of the invention is to obtain an assembly of electroconductive layers to form a reliable, robust electrode (especially in terms of stability and / or mechanical strength, thermal) without sacrificing its electroconductivity properties, its quality optical, nor the performance of the device incorporating it, nor cause difficulties of implementation.

The object of the invention is, in particular, to achieve an assembly of electroconductive layers to form a lower electrode of a reliable, robust electroluminescent system without sacrificing its electroconductivity properties, its optical quality, or the optical performance of the electroluminescent system. OLED, nor to create difficulties of realization.

By lower electrode in the sense of the invention it should be understood that reference is made to the electrode closest to the substrate, interposed between the carrier substrate and the OLED system. Incidentally, it is a question of achieving this objective without upsetting the known configurations of organic electroluminescent systems concerning the invention, and at a lower cost.

The aim is to develop essentially transparent, semi-transparent (both transparent and reflective) and reflective electrodes that are suitable for OLEDS forming active and passive matrix OLED screens, or used in general lighting

(architectural and / or decorative) or signage or even for other electronic applications.

For this purpose, the subject of the invention is a substrate, for organic electroluminescent device, carrying on a first main face of a so-called lower multilayer electrode, which successively comprises:

a so-called contact layer of dielectric material of the metal oxide and / or metal nitride type, a functional metallic layer with intrinsic properties of electrical conductivity,

a thin blocking layer directly on the metallic functional layer, the thin blocking layer comprising a metal layer with a thickness less than or equal to 5 nm, preferably between 0.5 and 2 nm, and / or comprising a layer with a thickness less than or equal to 10 nm, preferably between 0.5 and 2 nm, and which is based on stoichiometric metal oxide, stoichiometric metal oxynitride or stoichiometric metal nitride,

a coating comprising an overlayer, made of a dielectric material based on a metal oxide, forming an adaptation layer of the output work.

The thin blocking layer forms a protective layer or even a "sacrificial" layer which makes it possible to avoid the alteration of the functional metal, in particular pure and / or in thin layer, in one or both of the configurations. following:

if the layer which overcomes the functional layer is deposited using a reactive plasma (oxygen, nitrogen, etc.), for example if the oxide layer which surmounts it is deposited by cathodic sputtering,

if the composition of the layer which overcomes the functional layer is likely to vary during industrial manufacture (evolution of deposition conditions such as wear of a target, etc.), especially if the stoichiometry of an oxide and / or nitride type layer is changing. , thus modifying the quality of the functional layer and therefore the properties of the electrode (square resistance, light transmission, etc.),

if the electrode undergoes a heat treatment after the deposition. This protective or even sacrificial layer significantly improves the reproducibility of the electrical and optical properties of the electrode. This is very important for an industrial approach or a single weak dispersion of electrode properties is acceptable. The thin metallic blocking layer may preferably be made of a material selected from at least one of the following metals: Ti, V, Mn, Fe, Co, Cu, Zn, Zr, Hf, Al, Nb, Ni , Cr, Mo, Ta, W, or an alloy based on at least one of these materials. In particular, a thin blocking layer based on a metal chosen from niobium Nb, tantalum Ta, titanium Ti, chromium Cr or nickel Ni or an alloy from at least two of these is particularly preferred. metals, including niobium and tantalum (Nb / Ta), niobium and chromium (Nb / Cr) or tantalum and chromium (Ta / Cr) or nickel and chromium (Ni / Cr) alloys . This type of layer based on at least one metal has a particularly important effect of entrapment ("getter" effect).

A thin metal blocking layer can be easily manufactured without altering the functional layer. This metal layer may preferably be deposited in an inert atmosphere (that is to say without voluntary introduction of oxygen or nitrogen) consisting of noble gas (He, Ne, Xe, Ar, Kr). It is not excluded or annoying that on the surface this metal layer is oxidized during the subsequent deposition of a metal oxide layer.

Such a thin metal blocking layer also makes it possible to obtain excellent mechanical strength (resistance to abrasion, especially to scratches). This is especially true for stacks that undergo heat treatment, and thus a large diffusion of oxygen or nitrogen.

However, for the use of metal blocking layer, it is necessary to limit the thickness of the metal layer and therefore the light absorption to maintain sufficient light transmission. The thin blocking layer can be partially oxidized. This layer is deposited in non-metallic form and is therefore not deposited in stoichiometric form, but in sub-stoichiometric form, of the MO _x type, where M represents the material and x is a number less than the stoichiometry of the oxide of the material or type MNOx for an oxide of two materials M and N (or more). For example, TiOx, NiCrOx may be mentioned.

X is preferably between 0.75 and 0.99 times the normal stoichiometry of the oxide. For a monoxide, it is possible in particular to choose x between 0.5 and 0.98 and for a x-dioxide between 1.5 and 1.98. In a particular variant, the thin blocking layer is based on TiO _x and x can be in particular such that 1, 5 ≤ x ≤ 1, 98 or 1, 5 <x <1, 7, or even 1, 7 <x <1, 95.

The thin blocking layer may be partially nitrided. It is therefore not deposited in stoichiometric form, but in substoichiometric form, of the type MN _y , where M represents the material and y is a number less than the stoichiometry of the nitride of the material. Y is preferably between 0.75 and 0.99 times the normal stoichiometry of the nitride.

In the same way, the thin blocking layer can also be partially oxynitrided.

This thin oxidized and / or nitrided blocking layer can be easily manufactured without altering the functional layer. It is preferably deposited from a ceramic target, in a non-oxidizing atmosphere preferably consisting of noble gas (He, Ne, Xe, Ar, Kr). The thin blocking layer may be preferably nitride and / or substoichiometric oxide for further reproducibility of electrical and optical properties of the electrode.

The thin blocking layer chosen under stoichiometric oxide and / or nitride may be preferably based on a metal chosen from at least one of the following metals: Ti, V, Mn, Fe, Co, Cu, Zn, Zr, Hf, Al, Nb, Ni, Cr, Mo,

Ta, W, or an oxide of a stoichiometric alloy based on at least one of these materials.

Particularly preferred is a layer based on an oxide or oxynitride of a metal selected from niobium Nb, tantalum Ta, titanium Ti, chromium Cr or nickel Ni or an alloy from at least two of these metals, especially an alloy of niobium and tantalum (Nb / Ta), niobium and chromium (Nb / Cr) or tantalum and chromium (Ta / Cr) or nickel and chromium (Ni / Cr).

As a stoichiometric metal nitride, it is also possible to choose a silicon nitride SiN _x or AlNx aluminum or Cr Nx chromium layer, or TiNx titanium or a multi-metal nitride layer such as NiCrNx.

The thin blocking layer may have an oxidation gradient, for example M (N) OXi with variable Xi, the part of the blocking layer in contact with the functional layer is less oxidized than the portion of this layer furthest from the functional layer by using a particular deposition atmosphere.

The thin blocking layer may also be multilayer and include:

on the one hand an "interface" layer immediately in contact with said functional layer, this interface layer being made of a material based on non-stoichiometric metal oxide, nitride or oxynitride, such as those above, - on the other hand, at least one layer of a metallic material, such as those mentioned above, layer immediately in contact with said "interface" layer.

The interface layer may be an oxide, nitride, or oxynitride of a metal or metal that is or is present in the eventual adjacent metal layer.

The electrode according to the invention has a compatibility of the surface properties, in particular with organic electroluminescent systems, while having properties of electrical conductivity and / or of transparency or reflectivity that can be adjusted in a particular way, in particular by playing on the thickness of the metal functional layer, or even other layers and / or on the deposition conditions.

For a given organic structure of an OLED device, the electrode of the invention makes it possible to improve the yield in lm / W of the OLED by at least 5 to 10% for a brightness greater than 500 cd / m ² compared to an ITO electrode.

The electrode according to the invention can be over a large surface, for example an area greater than or equal to 0.02 m ² , or even 0.5 m ² or 1 m ² .

Preferably, the coating may have a thickness greater than or equal to 20 nm to provide an oxygen and / or water barrier and be a monolayer or a single or mixed doped or non-doped metal oxide multilayer, rather than a nitride layer more absorbent and / or insulating. An overcoat is preferably chosen with an electrical conductivity greater than 10 ⁵ S-Cm ¹ , or even ICH S. cm ¹ , easy and / or fast to achieve, transparent and economical layer.

The overlayer may preferably be based on at least one of the following conductive and transparent metal oxides:

indium oxide, zinc oxide, tin oxide, and their mixed oxides, in particular of a zinc and tin oxide Sn _x Zn _y O _z generally non stoichiometric and under amorphous phase, or of a mixed indium tin oxide (ITO), a mixed oxide of indium and zinc (IZO). This type of metal oxide can be doped typically between 0.5 and 5%. These are in particular S-doped tin oxide, or Al (AZO) doped zinc oxide, Ga (GZO), B, Sc, or Sb for a better stability of the deposition process, and / or further increase the electrical conductivity ,.

These conductive and transparent metal oxides can be surface stoichiometric to increase the work output.

The coating may consist solely of this overlayer, for example with a thickness greater than or equal to 15 nm, for example between 20 and 150 nm, to provide at the same time the oxygen barrier and / or water.

Since this overlayer may be preferably the last layer, a particularly stable ITO overlay is particularly preferred and it is moreover possible to retain the existing technologies for the manufacture and optimization of the OLED organic structure.

For economic reasons, if an ITO overlay is chosen, it is preferable that the latter is of thickness less than or equal to 30 nm, in particular and between 3 nm and 20 nm, and to add an additional layer underlying protection against oxygen for a cumulative total thickness preferably greater than or equal to 15 nm, at 30 nm, for example between 30 and 150 nm.

The overlayer may be alternatively or cumulatively based on at least one of the following stoichiometric metal oxides: nickel oxide, nickel oxide, aluminum oxide, titanium oxide, zirconium oxide, tantalum oxide, silicon oxide , silver oxide, gold, platinum, palladium, and preferably be less than or equal to 10 nm, for example between 1 and 5 nm.

These metal oxides are chosen stoichiometrically to be sufficiently electroconductive, and thin to be sufficiently transparent. The overlay can be deposited by a vacuum deposition technique, in particular by evaporation or magnetic field assisted sputtering, in particular at room temperature.

Even more preferably, an etching overcoat is preferably chosen with the same etching solution as the contact layer. In a design of the invention, to prevent corrosion of the functional layer, the electrode may comprise, between the blocking layer and the overcoat, a protective layer against oxygen and / or water, based on metal oxide especially when the overcoat is thin (less than or equal to 20 nm), as an overlay in ITO (or IZO / ITO or IZO) or NiOx type aforementioned material.

The protective layer may preferably be based on at least one of the following metal oxides distinct from the overcoat materials: zinc oxide, indium oxide, tin oxide, aluminum oxide, titanium oxide, zirconium oxide, tantalum oxide, silicon oxide. The metal oxide can be doped typically between 2 and 5%. It is in particular S-doped tin oxide, or Al-doped ZnO doped zinc oxide (AZO) for a better stability, Ga (GZO) to increase the conductivity, or even B , Sc, or Sb.

The protective layer may be based on a mixed oxide, in particular a zinc and tin oxide Sn _x Zn _y O _{z that is} generally non-stoichiometric and in an amorphous phase, or a mixed oxide of indium and aluminum oxide. tin (ITO), a mixed oxide of indium and zinc (IZO).

The protective layer may be a monolayer or a multilayer. This protective layer is preferably of (total) thickness between 3 and 150 nm, more preferably between 5 and 100 nm.

Naturally, the addition of this layer dedicated to the protection allows a greater freedom in the choice of the overlayer only chosen to have optimal surface properties including adaptation work output for OLEDS.

A protective layer which is easy and / or fast to produce is preferably transparent, especially a layer, doped or non-doped, based on ITO, IZO, Sn _x Zn ₇ O ₂ , ZnO _x .

Even more preferably, a protective layer which can be etched is preferably chosen with the same etching solution as the contact layer.

The protective layer can be deposited by a vacuum deposition technique, in particular by evaporation or preferably by magnetic field assisted sputtering, especially at ambient temperature.

In a preferred embodiment of the invention, the contact layer and the protective layer are identical in nature, in particular pure zinc oxide, doped or even alloyed, and preferably the overcoat comprises ITTO in a layer. more external.

It is preferable to adapt the oxidation state and / or the manufacturing conditions of the layer which overcomes the thin blocking layer (either the protective layer or the overcoat) depending on the nature of the thin blocking layer. . Thus, when the thin blocking layer is metallic, it is possible to choose an overlying stoichiometric layer and / or to use a highly reactive plasma in order to oxidize the metal layer in order to reduce its absorption.

Conversely, when the thin blocking layer is based on nitride and / or metal oxide under stoichiometric, depositing a pure or doped layer of metal oxide M (N) Ox ', with x' less than 1 to limit the overoxidation of the thin blocking layer and with x 'slightly less than 1 to avoid too much absorption of this overlying layer thicker.

In particular, a layer based on zinc oxide ZnOx ', with x' less than 1, preferably between 0.88 and 0.98, especially from 0.90 to 0.95, is particularly preferred.

Advantageously, the electrode according to the invention may have one or the following characteristics:

a square resistance less than or equal to 10 Ω / square for a functional layer thickness from 6 nm, preferably less than or equal to 5 Ω / square for a functional layer thickness from 10 nm, combined preferably with a light transmission TL greater than or equal to 70%, even more preferably at 80% which makes its use as a transparent electrode particularly satisfactory,

a square resistor less than or equal to 1 Ω / square for a functional layer thickness from 50 nm, preferably less than or equal to 0.6 Ω / square, preferably combined with a light reflection RL greater than or equal to 70% even more preferably at 80%, which makes its use as a reflecting electrode particularly satisfactory,

a square resistance of less than or equal to 3 Ω / square for a functional layer thickness starting from 20 nm, preferably less than or equal to 1.8 Ω / square, preferably combined with a ratio

TL on RL between 0, 1 and 0.7, which makes its use as a semi-transparent electrode particularly satisfactory,

the surface of the overlayer may be of roughness RMS (otherwise called Rq) less than or equal to 3 nm, preferably less than or equal to 2 nm, still more preferably less than or equal to

1, 5 nm, to avoid spike effects that drastically reduce the life and reliability of the O LED.

R. M. S roughness means "Root Mean Square" roughness. This is a measure of measuring the value of the mean square deviation of roughness. This roughness R. M. S, concretely, therefore quantifies on average the height of the peaks and troughs of roughness, with respect to the average height. Thus, an R. M. S roughness of 2 nm means a double peak amplitude.

It can be measured in various ways: for example, by atomic force microscopy, by a mechanical point system (using for example the measuring instruments marketed by VEECO under the name DEKTAK), by optical interferometry. The measurement is usually made on a square micrometer by atomic force microscopy, and on a larger area, of the order of 50 micrometers to 2 millimeters for mechanical systems to tip.

The functional layer is based on a pure material selected from silver Ag, Au, Cu or Al or based on said material alloyed or doped with Ag, Au, Al, Pt, Cu, Zn, In , Si, Zr, Mo, Ni, Cr, Mg, Mn, Co, Sn, Pd. There may be mentioned, for example, silver doped with Pd or a gold-copper alloy or a silver-gold alloy.

The functional layer may be deposited by a vacuum deposition technique, in particular by evaporation or preferably by magnetic field assisted sputtering, especially at room temperature.

If a high conductivity is particularly desired, it is possible to choose a pure material. If remarkable mechanical properties are particularly desired, it is possible to choose preferably a doped or alloyed material. A silver-based layer is preferably chosen for its conductivity and transparency.

The thickness of the selected functional layer based on silver may be between 3 to 20 nm, preferably between 5 to 15 nm. In this range of thicknesses, the electrode remains transparent. However, it is not excluded to have a much thicker layer especially in the case where the organic electroluminescent system operates in reflection. The thickness of the functional layer chosen based on silver may be between 50 and 150 nm, preferably between 80 and 100 nm.

The thickness of the selected silver-based functional layer may furthermore be between 20 to 50 nm to switch from operation mainly in transmission to operation mainly in reflection.

The contact layer may preferably be based on at least one of the following metal oxides stoichiometric or not: chromium oxide, indium oxide, zinc oxide, aluminum oxide, titanium oxide, molybdenum oxide, zirconium oxide, antimony oxide, tantalum oxide, silica oxide or even tin oxide. The metal oxide can be doped typically between 0.5 and 5%. It is in particular zinc oxide doped with Al (AZO), Ga (GZO), or even with B, Sc, or Sb for a better stability of deposition process, or even tin oxide doped with F or S.

The contact layer may be based on a mixed oxide, in particular a zinc and tin oxide Sn _x Zn _y O _{z which is} generally non-stoichiometric and in amorphous phase, or a mixed oxide of indium and tin ( ITO), a mixed oxide of indium and zinc (IZO).

The contact layer may be a monolayer or a multilayer. This layer is preferably of thickness (total) between 3 and 30 nm, more preferably between 5 and 20 nm.

A layer which is not toxic is preferably chosen, an easy and / or rapid layer to be produced, possibly transparent if necessary, in particular a doped or non-doped layer based on ITO, IZO, Sn _x Zn _y O _z , ZnO _x .

Still more preferably, a layer of crystalline nature is selected in a preferred growth direction to promote heteroepitaxy of the functional metal layer. This layer may especially be etchable by 'RIE'("Reactive ion etching" in English) or even more preferably by wet etching (easily integrated in the manufacturing phase and at atmospheric pressure). Preferably the same etching agent is used as the overcoat (acid solution, reactive plasma (s) type Ar, CF ₄ SF ₆ and O ₂ ...).

A ZnOx zinc oxide layer is preferably preferred, with preferably less than 1 x, even more preferably between 0.88 and 0.98, especially from 0.90 to 0.95. This layer can be pure or doped with Al or Ga as already indicated.

The Applicant has found that wet etching of the electrode in one step was possible even when the functional layer is relatively thick, for example between 30 and 70 nm (depending on the concentration and the etching solution chosen), particularly if the latter is relatively porous. Modifications in the deposition parameters may make it possible to obtain a certain porosity of this functional layer. It is thus possible to choose a relatively high pressure. We can vary also others parameters such as process temperature, mixing of gases used in the process.

Within the meaning of the invention, a material is etchable by an etching solution, if the latter is dissolved in the solution or is sufficiently corroded by the solution and at least the attachment is sufficiently weakened so that a small action mechanical, including a rinse with a low pressure jet is sufficient to remove the material.

The contact layer can be deposited by various techniques. It can be deposited, for example by a pyrolysis technique, especially in the gas phase (a technique often referred to by the abbreviation of C. V. D, for "Chemical Vapor Deposition").

The electroconductive layer may be deposited by a vacuum deposition technique, in particular by evaporation or preferably by magnetic field assisted sputtering, in particular at room temperature. The spray may be reactive (starting from metal targets or under-oxidized, in an oxidizing atmosphere) or non-reactive (starting from ceramic targets, in an inert atmosphere).

In particular, when the metal oxide-based contact layer is used, a thin, so-called lower, blocking layer can be inserted between the contact layer and the functional layer which is based on a metal of thickness less than or equal to at 5 nm, preferably between 0.5 and 2 nm, and / or an oxide, oxynitride, metal nitride, with a thickness of less than or equal to 10 nm, preferably between 0.5 and 2 nm, for example based on aforementioned materials for the blocking layer. This thin lower blocking layer (mono or multilayer) serves as a bonding layer, nucleation and / or protection during a possible heat treatment after deposition.

The electrode according to the invention may be further associated with a base layer capable of forming an alkaline barrier, especially when the contact layer is oxide-based.

The primer gives the electrode according to the invention many advantages. It is initially likely to be a barrier to the alkalis underlying the electrode. It protects the contact layer from pollution (pollution that may cause mechanical defects such as delaminations); it also preserves the electrical conductivity of the metallic functional layer. It also prevents the organic structure of an OLED device from being polluted by alkalis, thereby significantly reducing the life of the OLED.

The alkali migration can occur during the manufacture of the device, causing unreliability, and / or subsequently reducing its life.

The primer improves the bonding properties of the contact layer without significantly increasing the roughness of the assembly.

The invention is of course of particular interest for a carrier substrate capable of releasing alkalis such as silicosodocalcic glass including clear, extraclair.

Moreover, thanks to this particular stacking structure, a reliable electrode is also obtained, allowing significant productivity gains.

The basecoat is robust, easy and fast to deposit according to different techniques. It can be deposited, for example by a pyrolysis technique, especially in the gas phase (a technique often referred to by the abbreviation of C. V. D, for "Chemical Vapor Deposition"). This technique is interesting for the invention because appropriate settings of the deposition parameters make it possible to obtain a very dense layer for a reinforced barrier.

The primer can be deposited by a vacuum deposition technique, in particular by evaporation or magnetic field assisted sputtering, in particular at room temperature.

The primer may be optionally doped with aluminum to make its vacuum deposit more stable.

The bottom layer (monolayer or multilayer, optionally doped) may be between 10 and 150 nm thick, more preferably between 20 and 100 nm.

The bottom layer may preferably be:

based on silicon oxycarbide silicon oxide, layer of general formula SiOC, based on silicon nitride, silicon oxynitride, silicon oxycarbonitride, layer of general formula SiNOC, in particular SiN, in particular Si3N4.

The electrode may preferably comprise a wet etch stop layer between the base layer and the contact layer, in particular a layer based on tin oxide, in particular a layer of thickness between 10 and

100 nm, even more preferably between 20 and 60 nm. Or particularly, for the sake of simplicity, the wet etch stop layer may be part of or be the bottom layer: it may be preferably based on silicon nitride or it may be a layer which is based on silicon dioxide. silicon oxide or based on silicon oxycarbide and with tin to enhance by anti-etch property, layer of general formula SnSiOCN.

The wet etch stop layer serves to protect the substrate in the case of chemical etching or reactive plasma etching. Thanks to the etching stop (dry or wet), the base layer remains present even in the engraved area or zones ("patterned" in English). Also, the alkali migration, by edge effect, between the substrate in an etched area and an adjacent electrode portion (or even an organic structure) can be stopped. It is particularly preferable to have a bottom layer / stopping of etching (essentially) of Si3N4 silicon nitride, doped or otherwise. Silicon nitride is very fast to deposit and forms an excellent barrier to alkalis. In addition, thanks to its high optical index relative to the carrier substrate, it makes it possible to adapt the optical properties of the electrode by preferably playing on the thickness of this base layer. This thus makes it possible, for example, to adjust the color in transmission when the electrode is transparent or in reflection when the opposite face of the carrier substrate is a mirror.

Advantageously, the bottom layer and preferably the optional (wet) etch stop layer may substantially cover (almost) all of a main face of a glass plane substrate.

And even more preferably, the contact layers, lower blocking (optional), the functional layer, the thin blocking layer, and the coating are structured according to the same etching pattern and preferably by a single wet etching, which will be detailed further in the present application.

The etch stop layer, if present, is preferably intact, but may be slightly etched, for example one-tenth of its original thickness. It is preferably the same for the bottom layer if the etch stop layer is not present.

The electrode may be wider than the organic structure or other element from above to facilitate the taking of electrical contacts.

In addition, a border of the overlayer may be surmounted by a current feed band (continuous or discontinuous, forming part of a collector or a current distributor) preferably of thickness between 0.5 at 10 μm and in the form of a metal monolayer in one of the following metals: Mo, Al, Cr, Nd or metal alloy such as MoCr, AlNd or a metal multilayer such as MoCr / Al / MoCr. This band can be designed during the etching phase.

The power supply means may also be added after the etching, for example be enamel conductive, for example silver and screen printed.

In preferred embodiments of the invention, one or more of the following may also be used:

the total thickness of ITO or even indium in the electrode may be less than or equal to 30 nm or even 20 nm,

the total thickness (with the primer) is between 30 nm and 250 nm. The invention does not apply only to stacks having only one "functional" layer. It also applies to stacks comprising a plurality of functional layers, in particular two functional layers alternating with two or three coatings.

In the case of a multilayer stack functional, at least one, and preferably each functional layer is provided with a layer "on" blocking according to the invention (or even a layer of under blocking).

Thus, on the possible bottom layer and / or wet etch stop layer, the electrode comprises n times the following structure, with n a number integer greater than or equal to 1: the contact layer, optionally the thin lower blocking layer, the functional layer, the thin blocking layer, optionally the protective layer with water and / or oxygen, the structure being surmounted by a sequence comprising the contact layer, the functional layer, the thin blocking layer, optionally the protective layer with water and / or oxygen, said overlayer.

The planar substrate may be transparent (especially for emission through the susbtrate). The planar substrate may be rigid, flexible or semi-flexible.

Its main faces can be rectangular, square or even any other shape (round, oval, polygonal ...). This substrate may be of large size, for example with an area greater than 0.02 m ² , or even 0.5 m ² or 1 m ² and with a lower electrode occupying substantially the surface (in the structuring zones).

The planar substrate is preferably glass, in particular of silicosodocalcic glass. The substrate may advantageously be a glass having an absorption coefficient of less than 2.5 m ¹ , preferably less than 0.7 m ¹ at the wavelength of the OLED radiation (s).

For example, silicosodocalcic glasses with less than

0.05% Fe III or Fe 2 O 3, especially Saint-Gobain Glass Diamond, Pilkington Optiwhite glass, Schott B270 glass. All the extraclear glass compositions described in the document can be selected

WO04 / 025334.

In a selected configuration of an OLED system emission through the thickness of the transparent substrate, a portion of the emitted radiation is guided in the substrate.

Also, in an advantageous design of the invention, the thickness of the chosen glass substrate may be at least 1 mm, preferably at least

5 mm, for example. This reduces the number of internal reflections and thus extract more radiation guided in the glass, thus increasing the luminance of the light zone.

The edges of the wafer may also be reflective, and preferably include a mirror, to ensure optimal recycling of the guided radiation and the edges, together with the main face associated with the OLED system an external angle greater than or equal to 45 ° and less than 90 °, preferably greater than or equal to 80 °, to redirect the radiation over a wider extraction zone. The slice can be thus beveled.

To electrically separate the electrodes in JP2005-038642, the lower electrode is structured in several etching steps involving different acids and at different etch rates. First, the adaptation layer of the output work is engraved, then the metal layer and finally the contact layer.

The aim of the invention is to achieve an assembly of electroconductive layers to form a reliable, robust electrode (especially in terms of stability and / or thermal resistance, mechanical) without sacrificing its electroconductivity properties, its quality optical, nor the performance of the device incorporating it, nor cause difficulties in particular realization of wet etching. The invention thus proposes a method of acid etching a multilayer electrode on a substrate, in particular a glass substrate, comprising an acid etch stop layer, preferably based on silicon nitride, the electrode comprising:

a doped or non-doped metal oxide contact layer chosen from zinc oxide, tin and zinc mixed oxide, tin and indium oxide, indium oxide and zinc oxide (ZnOx, SnxZnyOz ITO); or IZO),

optionally a thin lower blocking layer directly under a functional layer, the layer comprising a metal layer with a thickness of less than or equal to 5 nm and / or a layer with a thickness of less than or equal to 10 nm, which is based on oxide or metal oxynitride or stoichiometric metal nitride,

the functional metallic layer with intrinsic properties of electrical conductivity with a thickness of less than or equal to 70 nm and chosen from silver and / or gold, doped or not,

a thin blocking layer directly on the functional layer, the layer comprising a metal layer of thickness less than or equal to 5 nm and / or a layer with a thickness less than or equal to at 10 nm, which is based on oxide or metal oxynitride or stoichiometric metal nitride,

optionally a doped or non-doped metal oxide protective layer selected from among zinc oxide, tin and zinc mixed oxide, tin and indium oxide, indium oxide and zinc oxide;

and an optionally conducting conductive oxide overcoat selected from indium oxide, zinc oxide, tin oxide and / or an overlayer with a thickness of less than or equal to 10 nm of stoichiometric oxide selected from molybdenum oxide, nickel oxide, aluminum oxide, titanium oxide, zirconium oxide, tantalum oxide, silicon oxide, silver oxide, gold oxide, platinum oxide and palladium oxide, the etching being carried out in one step and with an acid solution selected from pure nitric acid HNO3 in or mixture with hydrochloric acid HCl or pure hydrochloric acid in or mixture with iron trichloride FeCl3 in other words Fe III chloride.

Naturally the etching stop layer may be the primer already presented above.

It is thus possible to etch engraving patterns whose width and spacing vary according to the applications. The etching may be carried out in the presence of at least one metal strip of current feed, in the form of a monolayer preferably based on one of the following metals Mo, Al, Cr, Nd or alloy such as MoCr , AlNd or multilayer such as MoCr / Al / MoCr.

The invention also relates to an organic electroluminescent device comprising at least one carrier substrate, in particular glass substrate, provided with at least one organic electroluminescent layer disposed between the lower electrode as described above and a so-called upper electrode.

The OLED device can produce monochromatic light, especially blue and / or green and / or red, or be adapted to produce white light.

To produce white light several methods are possible: mixture of compounds (emission red green, blue) in a single layer, stack on the face of the electrodes of three organic structures (emission red green, blue) or two organic structures (yellow and blue), a series of three adjacent organic structures (emission red green, blue), on the face of the electrodes an organic structure in one color and on the other side of the phosphor layers adapted. The OLED device may comprise a plurality of adjacent organic electroluminescent systems, each emitting white light or, in a series of three, red, green and blue light, the systems being for example connected in series.

The device can be part of a multiple glazing, including a vacuum glazing or with air knife or other gas. The device can also be monolithic, include a monolithic glazing to gain compactness and / or lightness.

The OLED system may be glued or preferably laminated with another flat substrate said cover, preferably transparent such as a glass, using a lamination interlayer, in particular extraclair.

The laminated glazings usually consist of two rigid substrates between which is disposed a sheet or a superposition of polymer sheets of the thermoplastic type. The invention also includes so-called "asymmetrical" laminated glazings using a particularly rigid carrier substrate of the glass type and as a substrate covering one or more protective polymer sheets.

The invention also includes laminated glazings having at least one interlayer sheet based on a single or double-sided adhesive polymer of the elastomer type (that is to say not requiring a lamination operation in the conventional sense of the term, laminating imposing heating generally under pressure to soften and adhere the thermoplastic interlayer sheet).

In this configuration, the means for securing the cover and the carrier substrate may then be a lamination interlayer, in particular a sheet of thermoplastic material, for example polyurethane (PU), polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), or resin multi-component or one-component heat-curable (epoxy, PU) or ultraviolet (epoxy, acrylic resin). It is preferably (substantially) of the same size as the cover and the substrate. The lamination interlayer may make it possible to prevent bending of the bonnet, particularly for devices of large dimensions, for example with an area greater than 0.5 m ² .

In particular, the EVA offers many advantages: - it is not or little loaded with water in volume, it does not necessarily require a high pressurization for its implementation.

A thermoplastic lamination interlayer may be preferred to a cast resin cover because it is both easier to implement, more economical and possibly more watertight.

The interlayer optionally comprises a network of electroconductive son embedded in its so-called internal surface facing the upper electrode, and / or an electroconductive layer or electroconductive strips on the inner surface of the cover. The OLED system can be preferably placed inside the double glazing, with a particularly inert gas blade (argon for example).

The upper electrode may be an electroconductive layer advantageously chosen from metal oxides, especially the following materials: doped zinc oxide, in particular aluminum ZnO: Al or gallium

ZnO: Ga, - or doped indium oxide, especially with tin (ITO) or zinc doped indium oxide (IZO).

It is more generally possible to use any type of transparent electroconductive layer, for example a so-called "TCO" (for "Transparent Conductive Oxide" in English) layer, for example of thickness between 20 and 1000 nm.

It is also possible to use a thin metallic layer called "TCC" (for "Transparent Conductive Coating" in English) for example in Ag, Al, Pd, Cu, Pd, Pt In, Mo, Au and typically of thickness between 5 and 150. nm depending on the desired transmission / light reflection.

The electrode is not necessarily continuous. The upper electrode may comprise a plurality of conductive strips or conductive wires (grid). In addition, it may be advantageous to add a coating having a given functionality on the opposite side of the carrier substrate of the electrode according to the invention or on an additional substrate. It may be an anti-fog layer (using a hydrophilic layer), anti-fouling (photocatalytic coating comprising at least partially crystallized ΗO2 in anatase form), or an anti-reflection stack of type for example Si3N4 / SiO2 / Si3N4 / SiO2 or a UV filter such as a titanium oxide layer (TiO2). It may also be one or more phosphor layers, a mirror layer, at least one scattering zone light extraction.

The invention also relates to the various applications that can be found in these OLEDS devices, forming one or more transparent and / or reflecting luminous surfaces (mirror function) arranged both outside and inside. The device can form (alternative or cumulative choice) a lighting system, decorative, architectural, etc.), a signage display panel - for example of the type drawing, logo, alphanumeric signaling, including an emergency exit sign.

The OLED device can be arranged to produce a uniform light, especially for uniform illumination, or to produce different light areas of the same intensity or distinct intensity.

Conversely, one can seek a differentiated lighting. The organic electroluminescent system (OLED) produces a direct light region, and another light zone is obtained by extraction of OLED radiation which is guided by total reflections in the thickness of the selected glass substrate.

To form this other light zone, the extraction zone may be adjacent to the OLED system or on the other side of the substrate. The extraction zone (s) can be used, for example, to reinforce the illumination provided by the direct light zone, in particular for an architectural type of lighting, or to signal the luminous panel. The extraction zone or zones are preferably in the form of band (s) of light, in particular uniform (s), and preferably arranged (s) on the periphery of one of the faces. These strips can for example form a very bright frame. The extraction is obtained by at least one of the following means arranged in the extraction zone: a diffusing layer, preferably based on mineral particles and preferably with a mineral binder, the substrate made diffusing, in particular texture or rough. The two main faces may each have a direct light area.

When the electrodes and the organic structure of the OLED system are chosen to be transparent, an illuminating window can in particular be produced. Improved lighting of the room is not achieved at the expense of light transmission. By also limiting the light reflection, especially on the outside of the illuminating window, this also makes it possible to control the level of reflection, for example to comply with the anti-glare standards in force for building facades.

More broadly, the device, in particular transparent part (s) or entirely, may be: intended for the building, such as an external light glazing, an internal light partition or a (part of) light glass door including sliding, for a transport vehicle, such as a bright roof, a (part of) side window light, an internal light partition of a land vehicle, aquatic or aerial (car, truck train, plane, boat, etc.), intended for street furniture or professional such as a bus shelter panel, a wall of a display, a jewelery display or a showcase, a wall of a greenhouse, an illuminating slab, intended for interior furnishing, an element of a shelf or furniture, a front of a piece of furniture, an illuminating slab, a ceiling lamp, a refrigerator lighting tablet, an aquarium wall, intended for the backlighting of electronic equipment, in particular a display screen or display, possibly dual screen such as a television or computer screen, a touch screen. For example, it is possible to design a backlighting of a double-sided screen with different sizes, the small screen being preferably associated with a Fresnel lens for concentrating the light.

To form an illuminating mirror, one of the electrodes may be reflective or a mirror may be disposed on the opposite side of the OLED system, if it is desired to favor illumination of only one side in the direct light region.

It can also be a mirror. The illuminated panel can be used for lighting a bathroom wall or a kitchen worktop, to be a ceiling lamp.

OLEDs are generally dissociated into two major families depending on the organic material used.

If the electroluminescent layers are small molecules, it is called SM-OLED ("Small Molecule Organic Light Emitting Diodes"). The organic electroluminescent material of the thin layer consists of evaporated molecules such as, for example, the AlCl 3 complex (tris (8-hydroxyquinoline) aluminum), the DPVBi (4,4 '- (diphenylvinylene biphenyl)), the

DMQA (dimethyl quinacridone) or DCM (4- (dicyanomethylene) -2-methyl-6- (4-dimethylaminostyryl) -4H-pyran). The emissive layer may also be for example a layer of 4.4 ^{f, fl} 4 -tri (N-carbazolyl) TRIPHENYLAMINE (TCTA) doped with fac tris (2-phenylpyridine) iridium [Ir (ppy) 3].

In general, the structure of an SM-OLED consists of a stack of hole injection layers or "HIL" for "HoIe Injection

"Layer" in English, hole transport layer or "HTL" for "HoIe Transporting Layer" in English, emissive layer, electron transport layer or "ETL" for "Electron Transporting Layer" in English.

An example of a hole injection layer is copper phthalocyanine (CuPC), the hole transport layer may be, for example, N, N ¹ -Bis (naphthalenyl) -N, N'-bis ( phenyl) benzidine (alpha-NPB). The electron transport layer can be composed of tris- (8-hydroxyquinoline) aluminum (Alq3) or bathophenanthroline (BPhen).

The upper electrode may be a layer of Mg / Al or LiF / Al. Examples of organic electroluminescent stacks are for example described in US6645645.

If the organic electroluminescent layers are polymers, it is called PLED ("Polymer Light Emitting Diodes" in English). The organic electroluminescent material of the thin layer consists of these polymers (pLEDs) such as for example PPV for poly [pαrα-phenylene vinylene), PPP (poly [pαrα-phenylene), DO-PPP (poly (2 decyloxy-1,4-phenylene), MEH-PPV (poly [2- (2'-ethylhexyloxy) -5-methoxy-1,4-phenylene vinylene)]), CN-PPV (poly [2,5] -bis (hexyloxy) -1,4-phenylene- (1-cyanovinylene)]) or PDAF (poly (dialkylfluorene), the polymer layer is also associated with a layer which promotes the injection of holes (HIL) constituted by example of PEDT / PSS (poly (3,4-ethylene-dioxythiophene / poly (4-styrene sulfonate)).

An example of PLED consists of a following stack: a layer of poly (2,4-ethylene dioxythiophene) doped with poly (styren sulphonate) (PEDOT: PSS) of 50 nm,

a phenyl poly (p-phenylenevinylenene) Ph-PPV layer of 50 nm. The upper electrode may be a layer of Ca.

The invention will now be described in more detail using non-limiting examples and figures:

FIG. 1 is a schematic sectional view of an organic electroluminescent device, for a uniform (back) illumination, which comprises a lower electrode according to the invention in a first embodiment, FIG. 2 is a partial view showing this lower electrode in more detail, Figure 3 illustrates a method of manufacturing and etching of this electrode, Figure 4 illustrates a schematic sectional view of an organic electroluminescent device, for a (retro) uniform illumination, which is arranged on several zones, and comprises a lower electrode according to the invention in a second embodiment, FIGS. 5 and 6 illustrate schematic views from above showing two diagrams of electrical electrode connections similar to those used in the second embodiment, Figure 7 shows a schematic side sectional view of an organic electroluminescent device used for differentiated illumination.

It is specified that for the sake of clarity the various elements of the objects (including angles) represented are not necessarily reproduced on the scale.

FIG. 1 is deliberately very schematic, it shows in section an organic electroluminescent device 10 (emission through the substrate or "bottom emission" in English) comprising a planar substrate of sand-soda-lime glass 1, clear or extraclear, of 2, 1 mm thick, with first and second main faces 1 1, 12. The first main face 1 1 comprises:

a bottom layer 2, deposited directly on the first main face 1 1, also acting as a wet etching stop, made of silicon nitride, with a thickness between 10 nm and 80 nm, and covering substantially all of the first main face 1 1,

a lower electrode 3 deposited directly on the transparent, chosen, etched bottom layer 2, comprising a stack of layers (see FIG. 2) of the type:

- a contact layer 31, chosen from ZnO x doped or not, Zn _x Sn ₂ O _7, ITO or IZO,

a preferably pure silver functional layer 32, directly on the contact layer 31, a thin blocking layer 32 'directly on the functional layer 32, a metallic layer preferably obtained by a metal target with a neutral or nitride plasma and / or oxide of one or more metals such as Ti, Ni, Cr, preferably obtained by a ceramic target with a neutral plasma, - a coating formed:

- a protective layer 33 selected from ZnO, Zn _x Sn _y O _z, ITO or IZO, the contact layer and the protective layer against water and / or oxygen being identical in nature, an overlay 34 for adapting the output work, preferably the ZnO stack: Al / Ag / Ti, TiOx or NiCr /

ZnO: A1 / ITO of respective thicknesses 5 to 20 nm for ZnO: A1,

5 to 15 nm for silver, 0.5 to 2 nm for TiOx, Ti, NiCr, 5 to 20 nm for ZnO: A1, 5 to 20 nm for ITO,

an organic electroluminescent system 4, for example an SM-OLED of following structure:

an alpha-NPD layer,

a TCTA + Ir (ppy) 3 layer, a BPhen layer,

a LiF layer, a reflecting top electrode 5, in particular a metal electrode, in particular based on silver or aluminum.

The set of layers 2 to 5 was deposited by magnetic field sputtering at room temperature.

The lower electrode 3 has the following characteristics:

a square resistance less than or equal to 5 Ω / square,

a TL light transmission greater than or equal to 70% (measured on a full layer, before structuring), and a luminous reflection RL less than or equal to 20%,

- An RMS roughness (or Rq) less than or equal to 3 nm measured by optical interferometry, on a square micrometer by atomic force microscopy.

For Si ₃ N ₄ 25nm / ZnO: Al 2 O 3 / Ag 2nm / Tiinm / ZnO: Al ₂ onm / IT ₂ onm, a TL of 83%, a stable square resistance, an RMS roughness of 1.3 nm are obtained. The Ti layer is deposited by sputtering in an inert atmosphere

(that is to say without voluntary introduction of oxygen or nitrogen) consisting of noble gas (He, Ne, Xe, Ar, Kr).

The deposition conditions for each of the layers are preferably as follows:

The Si3N4-based layer is deposited by reactive sputtering using an aluminum doped silicon target at a pressure of 0.8 Pa in an argon / nitrogen atmosphere, The silver-based layer is deposited using a silver target, at a pressure of 0.8 Pa in a pure argon atmosphere,

The Ti layer is deposited using a titanium target, at a pressure of 0.8 Pa in a pure argon atmosphere, the ZnO-based layers are deposited by reactive sputtering using an aluminum doped zinc target under a pressure of 0.3 Pa and in an argon / oxygen atmosphere,

• The ITO layer is deposited using a ceramic target in an argon / oxygen atmosphere. For a series of three samples, each carrying this stack

Si3N ₄ 25nm / ZnO: Al 2 O / Ag 2nm / Tiinm / ZnO: Al ₂ onm / IT ₂ onm, a square resistor of 4.35 Ohm / square, 4.37 Ohm / square, 4.44 Ohm / square, is obtained respectively. Ohm / square is a maximum deviation of 0, 1 1 and a mean square resistance of 4.39 Ohm / square.

For a series of three comparative samples, each carrying this stack without the thin blocking layer, a square resistance of 4.4 Ohm / square, 4.75 Ohm / square, 4.71 Ohm / square is obtained respectively. maximum deviation of 0.35 three times higher and a mean square resistance of 4.62

Ohm / square.

For this organic structure, the electrode of the invention makes it possible to improve the yield in lm / W of the OLED by at least 5 to 10% for a gloss greater than 500 cd / m ² with respect to an electrode. ITO.

The first electrode may alternatively comprise a thin lower blocking layer, in particular a metal layer preferably obtained by a metal target with a neutral plasma or nitride and / or oxide of one or more metals such as Ti, Ni, Cr, preferably obtained by a ceramic target with a neutral plasma.

The first electrode may alternatively also be a semi-transparent electrode. For Si3N4 20 nm / ZnO: Al ₂ 0 nm / Ag 30 nm / TiOXnn OR

NiCrinm / ZnO: Al 40 nm / ITO 20 m gives a TL of about 15%, an RL of about 80%, a square resistance of 0.9 Ohm / square.

The first electrode may also be a reflective electrode. The lower electrode 3 overflows on one side of the glass 1. The edge of the overlay 34 is thus surmounted by a first metal strip 61 of feed current, preferably of thickness between 0.5 to 10 microns, for example 5 microns, and in the form of a layer of one of the following metals: Mo, Al, Cr, Nd or alloy such as MoCr , AlNd or multilayer such as MoCr / Al / MoCr.

The lower electrode 3 may alternatively comprise the base layer and an n times repeated structure, with n being an integer greater than or equal to 1, this structure being the following: the contact layer / the functional layer / the thin layer of blocking / possibly the protective layer with water and / or oxygen.

This structure is surmounted by a sequence comprising the contact layer / the functional layer / possibly the protective layer with water and / or oxygen / said overlayer.

In the case of a stack of organic structures for example emitting in the red, the green, the blue, to produce a white light, one can also repeat three times all the elements 3, 4, 5 or simply use a multilayer Al / ITO or Ag / optionally a thin layer of similar blocking / ITO or Ag / possibly a thin layer of similar blocking / ZnO / ITO for the additional lower electrodes.

The upper electrode protrudes on the opposite side of the glass 1. This edge of the upper electrode 5 is optionally surmounted by a second metal current supply strip, preferably similar to the first metal strip. This second band is preferable in the case where the upper electrode is less than or equal to 50 nm in thickness.

The second electrode may indeed also be, alternatively, a transparent or semi-transparent electrode and for example be identical to the first electrode. It is possible to report in this case a reflector on the second face 12, for example a metal layer with a thickness of 150 nm

An EVA-type sheet can make it possible to flick the glass 1 to another glass, preferably with the same characteristics as the glass 1. Optionally, the face of the glass 12 facing the EVA sheet is provided with a given feature stack described above. later.

The lower electrode 3 is in two parts spaced apart by the structuring zone 310, for example a line.

Wet etching is used to electrically separate the electrode lower 3 of the upper electrode of the device 10.

To engrave the entire lower electrode (contact, functional, blocking, protective and overlayer layers) according to the same etching pattern and at once, the layers - previously partially masked with the aid of an acid-resistant adhesive tape or alternatively with a photolithography mask - with one of the following acid solutions: with HCl (for example at 40%), or with HCl (for example at 4%), or to a mixture of HCl (for example 4%) and HNO (for example 7%), or to a mixture of HCl and FeCl 3, with HNO ₃ between 10 and 18%.

The etching with hydrochloric acid leads to very homogeneous etching profiles. The nitric acid and hydrochloric acid mixture also gives interesting results. The mixture of HCl and FeCl 3 is conventionally used for ITO.

The etching profile, the etching time and the resolution can be adapted using mixtures of the two acids and varying the concentrations. It is thus possible to etch engraving patterns whose width and spacing vary according to the applications.

For OLED displays with a small passive matrix (for displaying an electronic equipment such as a mobile phone, display, personal assistant, MP3 player, etc.), the width of each etched zone may typically be 10 to 20 μm. , each etched zone being spaced from 10 to 50 μm, for example 35 μm (corresponding to the width of each electrode zone).

For large passive matrix OLED screens, for example for advertising display, signage, the width of each engraved area may be of the order of 0.5 mm and the width of each electrode zone may be a few mm , a few cm or more ...

For homogeneous illumination, the width of each engraved zone may be less than or equal to 100 μm, even more preferentially to 50 μm, whatever the size of the screen.

Figure 3 illustrates a method of manufacturing and etching this electrode.

After depositing the bottom layer 2, the electrode 3 and the metal layer (monolayer or multilayer) for the current supply 6, this layer 6 is etched with a solution that does not damage the electrode for example sodium hydroxide (step E1), then one-step etching of the lower electrode 3 as already indicated (step E2), followed by the deposition of the OLED system 4 and the upper electrode 5 for example in Al above (step E3).

FIG. 4 illustrates a schematic sectional view of an organic electroluminescent device 10 ', for a uniform (retro) illumination, which is arranged in several zones, and comprises a lower electrode according to the invention in a second embodiment. This second device 10 'differs from the first device 10 by the elements described below.

The device 10 'comprises two adjacent organic electroluminescent systems 4a and 4b, each of which preferably emits white light or, alternatively, a series of three, of red, green and blue light. The systems 4a and 4b are connected in series. The lower electrode is divided mainly into two rectangles or squares 3a, 3b of about ten cm each side exceeding one side (left in the figure). These electrode zones are separated by the etching zone 310. The second electrode zone 3b is separated by the etching zone 320 from a "residual" lower electrode zone (to the right of the figure). The first lower electrode section 3a is partially covered by a first metal strip forming a "bus bar" 61.

The upper electrode is also divided. The first upper electrode section 5a protrudes to the right side and covers the left edge of the second lower electrode section 3b. The second upper electrode section 5b protrudes to the right side and covers the left edge of the residual lower electrode section and is covered by a second metal band forming a "bus bar" 62. The etching areas 310, 320 are for example strips of width 20 to 50 microns to be almost invisible to the naked eye.

Figures 5 and 6 illustrate schematic top views showing two diagrams of electrode electrical connections 20, 20 'similar to those used in the second embodiment.

In FIG. 5, three organic electroluminescent systems 4a to 4c are connected in series. Etching areas 310 and 320 are strips of width 20 to 50 microns to be almost invisible to the naked eye.

The lower electrode is divided into 3 rectangles of about 10 cm wide, each protruding by one side (left in the figure). They are separated by the etching areas 310, 320. The upper electrode 5a to 5c is also divided into three. The first lower electrode section is partially covered by a first metal strip forming a "bus bar" 61.

The first two upper electrode sections 5a, 5b protrude to the right side and overlap the left edge of the adjacent lower electrode section. The third upper electrode section 5c protrudes to the right side and overlaps the left edge of a residual lower electrode section and is partially covered by a second metal bus bar 62. In FIG. organic electroluminescent systems 4a to 4c,

4 'to 4'c are connected in series (three at the top, three at the bottom). Etching areas 310 to 330 are both lateral 310, 320 and longitudinal 330, and are strips of width 20 to 50 microns to be almost invisible to the naked eye.

The lower electrode is divided into six squares of about ten cm each side protruding by one side (left in the figure). The lower electrode sections are separated by the etching areas 310 to 330 '. The first busbar strip is cut to form a current collector with two strips 61 ', 62' on the left side of the figure.

The upper electrode 5a to 5c, 5'a to 5'c is also divided into six. The first two upper sections (upper left in the figure) of the upper electrode 5a to 5b protrude to the right side and cover the left edge of the third section of the adjacent lower electrode.

The upper third upper electrode section 5b protrudes to the side right and covers the left edge of the residual lower electrode section and is covered by a metal strip forming 610 electrical interconnection with the third lower section (bottom right in the figure) electrode.

The first two lower sections (bottom left in the figure) of the upper electrode 5 'to 5T? protrude to the right side and overlap the left edge of the third lower section of the adjacent lower electrode.

Fig. 7 is a schematic side sectional view of an organic electroluminescent device 10 used for differentiated illumination.

This device 10 firstly comprises a plane transparent substrate, preferably a preferably thick glass sheet 1, for example 4 or

6 mm, and with an absorption coefficient less than or equal to 2.5 m ¹ in the visible. An extraclear soda-lime glass having an absorption coefficient of less than 0.7 m ¹ in the visible is preferably chosen. This glass 1 has first and second parallel main faces 12, 1 1 and a wafer 13. The device is closed in its lower part by a cover, not shown here.

The electroluminescent device 10 of the OLED type includes a system

OLED 4 arranged on a lower electrode type

ZnO: Al 20 nm / Ag i2 nm / Tii _nm / ZnO: Al 20 nm / ITO 20 nm which is on a 25 nm SiaN4 primer layer and arranged on the first main face 1 1. direct light 71, 72 on both sides of the glass 1.

The first direct light region 71, on the opposite side of the OLED system 4 with respect to the substrate 1, covers the central part of the first main face 12. The second direct light zone 72, on the OLED system side 4, extends over the entire second main face 1 1. The characteristics of the device 10 are adapted so that the luminance L1 of the first direct light region 71 is preferably greater than the luminance L2 of the second direct light region 72 (as symbolized by the thick arrow Fl and thin arrow F2).

To have L1 greater than L2, the device 10 is therefore main emission by the lower electrode. For example, we choose Ll equal to about 1000 cd / m ² and L2 equal to about 500 cd / m ² for visual comfort.

The device 10 is also a source of radiation guided in the thickness of the glass 1, by total reflections. Guided radiation is extracted edges of the first face 1 1 by means of a diffusing layer 7 for example based on mineral diffusing particles dispersed in a mineral binder. This defines a third light zone 73 forming a peripheral light frame. As a variant, the diffusing layer 7 only forms lateral strips or peripheral longitudinal strips.

To promote the extraction of the guided radiation, each edge forming the wafer 13 forms with the second main face 1 1 associated with the light source 10 an external angle greater than 80 ° and comprises a mirror 14, for example a metallic silver layer or copper. The device 10 may be intended for the building, be an illuminating window, a door, a greenhouse wall or a canopy or be a vehicle side window or a bright roof. The second face 12 is the inner face (the most illuminating face).

When the device 10 is turned on, the direct light area 71 31 may be able to preserve the privacy of a person inside a room, a cabin at night or in a dark environment. It suffices for that the luminous flux sent by the glazing is at least equal to that reflected and returned by the room.

The device 10 may form a double glazing, the device 2 being preferably located in the space filled with internal gas between the glass 1 and an optionally additional glass thinner.

The device 10 thus designed can also serve as a transparent and illuminating shelf, refrigerator light shelf, transparent partition and illuminating between two parts, wall of an aquarium. The characteristics of the device 10 can then be adapted so that the luminance L1 of the first direct light region 71 is substantially equal to the luminance L2 of the second direct light region 72.

The light zones 71, 72 are uniform. The device 10 may also have, alternatively, at least one discontinuous direct light zone and / or forming a drawing, a logo, a signaling.

ADDITIONAL FUNCTIONS

As already said, it may be wise to functionalize the second face of the carrier substrate 1 (opposite side to the organic electroluminescent system).

Thin layers are thus deposited on the surface to give them a particular property, for example that which consists in allowing the substrate to remain as clean as possible, whatever the environmental aggressions, that is to say aimed at permanence of the surface and appearance properties over time, and in particular making it possible to space the cleanings, by succeeding in gradually eliminating the soils gradually deposited on the surface of the substrate, in particular soils of organic origin such as fingerprints or volatile organic products present in the atmosphere, or even soot-type soiling, dust pollution.

However, it is known that there are certain semiconductor materials, based on metal oxide, which are capable, under the effect of radiation of adequate wavelength, initiating radical reactions causing the oxidation of organic products: we generally speak of "photo-catalytic" or "photo-reactive" materials.

It is known in the field of substrates with a glazing function, the use of photocatalytic coatings on substrate, which have a marked "antifouling" effect and that can be manufactured industrially. These photo-catalytic coatings generally comprise at least partially crystallized titanium oxide, incorporated in said coating in the form of particles, in particular of size ranging from a few nanometers (3 or 4) to 100 nm, preferably around 50 nm for the essential crystallized form anatase or anatase / rutile.

Titanium oxide is in fact part of the semiconductors which, under the action of light in the visible range or ultraviolet, degrade organic products which are deposited on their surface.

Thus, according to a first exemplary embodiment, the photo-catalytically-active coating results from a solution based on nanoparticles of TiO 2 and a mesoporous silica (SiO 2) binder. According to a second exemplary embodiment, the photo-catalytically-active coating results from a solution based on ΗO2 nanoparticles and an unstructured silica (SiO 2) binder.

Whatever the embodiment of the photo-catalytic coating, at the level of the titanium oxide particles, the choice was furthermore made on titanium oxide which is at least partially crystallized because it has been shown to be much more efficient in terms of photocatalytic properties than amorphous titanium oxide. Preferably, it is crystallized in anatase form, in rutile form or in the form of a mixture of anatase and rutile.

The coating is produced in such a way that the crystallized titanium oxide it contains is in the form of "crystallites", that is to say single crystals, having an average size of between 0.5 and 100 nm, preferably 3 to 60 nm. It is indeed in this size range that titanium oxide appears to have an optimal photo-catalytic effect, probably because the crystallites of this size develop a large active surface.

The photocatalytically active coating may also comprise, in addition to titanium oxide, at least one other type of mineral material, especially in the form of an amorphous or partially crystalline oxide, for example silicon oxide (or a mixture of oxides), titanium, tin, zirconium or aluminum. This mineral material can also participate in the photo-catalytic effect of crystallized titanium oxide, itself having a certain photo-catalytic effect, even small compared to that of crystallized ΗO2, which is the case of the amorphous or partially crystalline titanium oxide.

It is also possible to increase the number of charge carriers by doping the crystalline lattice of titanium oxide by inserting at least one of the following metallic elements: niobium, tantalum, iron, bismuth, cobalt, nickel, copper, ruthenium, cerium molybdenum. This doping can also be done by a surface doping only of the titanium oxide or of the entire coating, surface doping achieved by covering at least a portion of the coating with a layer of oxides or salts metal, the metal being selected from iron, copper, ruthenium, cerium, molybdenum, vanadium and bismuth.

Finally, the photo-catalytic phenomenon can be amplified by increasing the yield and / or kinetics of the photo-catalytic reactions by covering the titanium oxide or at least a part of the coating which incorporates it with a noble metal in the form of a thin layer. platinum, rhodium, silver.

The coating with photocatalytic property also has an outer surface of hydrophilic and / or oleophilic pronounced, especially in the case where the binder is inorganic, which brings two significant advantages: a hydrophilic character allows a perfect wetting of water which can be deposited on the coating, thus facilitating cleaning.

Together with a hydrophilic character, it can also have an oleophilic character, allowing the "wetting" of organic soils which, as for water, then tend to deposit on the coating in the form of a continuous film less visible than " spots well localized. An "organic dirt" effect is thus obtained in two stages: as soon as it is deposited on the coating, the soil is already not very visible. Then, gradually, it disappears by radical degradation initiated by photocatalysis. The thickness of the coating is variable, it is between a few nanometers and a few microns, typically between 50 nm and 10 microns.

In fact, the choice of the thickness may depend on various parameters, in particular the envisaged application of the substrate, or the size of the cristallO 2 crystallites in the coating. The coating may also be chosen with a more or less smooth surface: a low surface roughness may indeed be advantageous if it makes it possible to develop a larger active photo-catalytic surface. However, too pronounced, it can be penalizing by favoring the encrustation, the accumulation of soiling.

According to another variant, the functionality that is reported on the other side of the substrate may be constituted by an anti-reflection coating.

The following are the preferred ranges of the geometric thicknesses and indices of the four layers of the antireflection stack, this stack being referred to as A: ni and / or ri3 are between 2.00 and 2.30, in particular between 2, 15 and 2.25, and preferably close to 2.20. n ₂ and / or n ₄ are from 1.35 to 1.65. ei is between 5 and 50 nm, especially between 10 and 30 nm, or between 15 and 25 nm. e ₂ is between 5 and 50 nm, especially less than or equal to 35 nm or 30 nm, in particular between 10 and 35 nm. e3 is between 40 and 180 nm and preferably between 45 and 150 nm. e4 is between 45 and 1 10 nm and preferably between 70 and

105 nm.

The most suitable materials for forming the first and / or third layer of the stack A, which is of anti-reflective type, those with a high index, are based on mixed nitride of silicon and zirconium or a mixture of these nitrides. mixed. In a variant, these high-index layers are based on mixed nitrides of silicon and tantalum or a mixture of these. All these materials may be optionally doped to improve their chemical and / or mechanical and / or electrical resistance properties.

The most suitable materials for constituting the second and / or fourth layer of the stack A, those with low index, are based on silicon oxide, oxynitride and / or silicon oxycarbide or based on a mixed oxide of silicon and aluminum. Such a mixed oxide tends to have a better durability, especially chemical, than pure SiO 2 (an example is given in patent EP 791 562). The respective proportion of the two oxides can be adjusted to achieve the expected improvement in durability without greatly increasing the refractive index of the layer.

A preferred embodiment of this antireflection stack is of the substrate / Si ₃ N ₄ / SiO ₂ / Si ₃ N ₄ / SiO _{2 form} .

It goes without saying that the invention applies in the same way to systems using other electroluminescent systems than those described in the examples.

Claims

1. Substrate (1), for organic electroluminescent device (10, ICC), carrier on a first main face (1 1) a multilayer electrode (3), said lower, which comprises successively: a so-called contact layer (31) to metal oxide base and / or metal nitride, a metal functional layer (32) with intrinsic properties of electrical conductivity, - a coating (33, 34) having an overcoat of metal oxide dielectric material (34), forming an output work adaptation layer, characterized in that the multilayer electrode (3) further comprises a thin blocking layer (32) directly on the functional layer (32), the thin blocking layer comprising a layer metal with a thickness of less than or equal to 5 nm and / or a layer with a thickness of less than or equal to 10 nm, which is based on a sub stoichiometric metal oxide, on stoichiometric metal oxynitride or on stoichiometric metal nitride.

2. Substrate (1) according to claim 1 characterized in that the thin blocking layer (32 ^ is a metal layer, nitride and / or metal oxide based on at least one of the following metals: Ti, V, Mn, Fe, Co, Cu, Zn, Zr, Hf, Al, Nb, Ni, Cr, Mo, Ta, W, or an alloy based on at least one of said materials and preferably niobium, tantalum , titanium, chromium or nickel or an alloy from at least two of said metals.

3. Substrate (1) according to one of the preceding claims characterized in that the overcoat (34) is based on at least one of the following metal oxides: conductive oxide optionally mixed and / or doped and / or surstoechiometric in surface chosen from indium oxide, zinc oxide, tin oxide, such as tin oxide doped with Sb, or zinc oxide doped with Al, Ga, possibly being a mixed oxide especially mixed indium and tin oxide, mixed indium zinc oxide, zinc and tin mixed oxide, and / or stoichiometric oxide selected from molybdenum oxide, nickel oxide, aluminum oxide , titanium oxide, zirconium oxide, tantalum oxide, silicon oxide, silver oxide, gold oxide, platinum oxide, palladium oxide, optionally doped and mixed, the stoichiometric oxide undercoat being preferably of thickness less than or equal to 10 nm.

4. Substrate (1) according to one of the preceding claims, characterized in that the coating (33, 34) comprises, between the thin blocking layer (32 ^ and the overlay (34), a protective layer (33) against water and / or oxygen based on at least one of the following metal oxides: indium oxide, zinc oxide, tin oxide, aluminum oxide, titanium oxide, zirconium oxide, tantalum oxide, silicon oxide, this layer being optionally doped, such as tin oxide doped with Sb, or zinc oxide doped with Al, Ga, and / or possibly being a mixed oxide, especially mixed indium oxide and tin, mixed oxide of indium and zinc, mixed oxide of zinc and tin.

5. Substrate (1) according to one of the preceding claims, characterized in that the coating (33, 34) is of greater than or equal to 20 nm thick and preferably based on metal oxide.

6. Substrate (1) according to one of the preceding claims, characterized in that the contact layer (31) and the protective layer against water and / or oxygen (33) are identical in nature, in particular to zinc oxide base, optionally doped with Al, and preferably the overcoat (34) is mixed tin oxide and indium.

7. Substrate (1) according to one of the preceding claims, characterized in that the electrode (3) has a TL light transmission greater than or equal to 70% and a square resistance less than or equal to 10 Ω / square for a thickness functional layer starting from 6 nm, preferably less than or equal to 5 Ω / square for a functional layer thickness starting from 10 nm or in that it has a light reflection RL greater than or equal to 70% or it has a square resistance less than or equal to 3 Ω / square for a functional layer thickness from 20 nm, preferably less than or equal to 1.8 Ω / square, preferably combined a ratio TL on RL between 0.1 and 0.7.

8. Substrate (1) according to one of the preceding claims characterized in that the functional layer (32) is based on a pure material selected from silver, gold, aluminum, copper, or to base of said material alloyed or doped with Ag, Au, Pd, Al, Pt, Cu, Zn, Cd, In, Si, Zr, Mo, Ni, Cr, Mg, Mn, Co, Sn, especially a gold and silver alloy or gold and copper.

9. Substrate (1) according to one of the preceding claims, characterized in that the thickness of the functional layer (32) chosen based on silver is between 3 to 20 nm, preferably between 5 to 15 nm or in that the thickness of the selected functional layer based on silver is between 20 to 50 nm or in that the thickness of the chosen functional layer based on silver is between 50 and 150 nm, preferably between between 80 to 100 nm.

10. Substrate (1) according to one of the preceding claims, characterized in that the contact layer (31) is based on at least one of the following metal oxides: chromium oxide, indium oxide, oxide of zinc optionally stoichiometric, aluminum oxide, titanium oxide, molybdenum oxide, zirconium oxide, antimony oxide, tin oxide, tantalum oxide, silicon oxide, optionally doped, such as oxide of F, Sb-doped tin, or doped zinc oxide, optionally being a mixed oxide, especially a mixed indium tin oxide, a mixed indium zinc oxide, mixed zinc oxide, and of tin and in that the contact layer is preferably between 3 and

30 nm.

1 1. Substrate (1) according to one of the preceding claims, characterized in that the electrode comprises a thin so-called lower blocking layer, in direct contact with the contact layer and the functional layer metal and oxide-based , nitride, stoichiometric metal oxynitride with a thickness of less than or equal to 10 nm and / or a metal layer with a thickness of less than or equal to 5 nm.

12. Substrate (1) according to one of the preceding claims, characterized in that the first main face (1 1) comprises, under the electrode (3), a base layer (2) capable of forming an alkali barrier the bottom layer (2) is a layer, optionally doped, selected from a layer based on silicon oxide, silicon oxycarbide, based on silicon nitride, silicon oxynitride, oxycarbonitride, silicon, preferably of thickness between 10 and 150 nm.

Substrate (1) according to the preceding claim characterized in that the first main face (1 1) comprises a wet etch stop layer between the base layer and the contact layer, in particular an oxide-based layer. of tin, or in that an etch stop layer (2) is part of or forms the primer, and preferably is based on silicon nitride or is based on silicon oxide or silicon oxycarbide with tin.

14. Substrate (1) according to one of claims 12 and 13 characterized in that the bottom layer and preferably the optional wet etch stop layer (2) substantially cover the whole of the first major face of the substrate chosen glass and plane and the contact layers (31), the possible thin lower blocking layer, the functional layer (32), the thin blocking layer (32 ^ and the coating (33) are etched in the same pattern of etching and preferably by a single wet etching.

15. Substrate (1) according to one of the preceding claims characterized in that on the possible bottom layers and / or wet etch stop layer is arranged n times the following structure, with n an integer greater than or equal to 1: the contact layer, optionally the thin lower blocking layer, the functional layer, the thin blocking layer, optionally the protective layer with water and / or oxygen, the structure being surmounted by a sequence comprising the contact layer, the functional layer, the thin blocking layer, said coating optionally comprising the protective layer with water and / or oxygen and comprising said overlayer.

16. Substrate (1) according to one of the preceding claims, characterized in that a border of the overlay (34) is surmounted by a metal strip a current feed (61, 61 ', 62), preferably having a thickness of between 0.5 and 10 μm, and in the form of a monolayer of one of the following metals: Mo, Al, Cr, Nd or alloy such as MoCr, AlNd or a multilayer such as MoCr / Al / MoCr.

17. Substrate (1) according to one of the preceding claims, characterized in that the substrate is flat and silicosodocalcic glass (1) preferably clear or extraclair.

18. Substrate (1) according to one of the preceding claims, characterized in that the second main face (12) comprises a functional coating selected from: an antireflection multilayer, an anti-fog or antifouling layer, an ultraviolet filter, including a layer of titanium oxide, a phosphor layer, a mirror layer, a light scattering zone (73).

19. A method of acid etching a multilayer electrode (3) on a substrate (1), in particular glass, comprising on a main face an etching stop layer, preferably based on silicon nitride, and the electrode said lower on the etch stop layer, said electrode comprising: a doped or non-doped metal oxide contact layer selected from zinc oxide, tin and zinc mixed oxide, tin and indium, of zinc and indium, optionally a thin lower blocking layer directly under a functional layer, the thin layer comprising a metal layer of thickness less than or equal to 5 nm and / or a layer with a thickness less than or equal to 10 nm, which is based on metal oxide or oxynitride or on stoichiometric metal nitride, the doped or non-doped metallic functional layer with intrinsic properties of electrical conductivity, with a thickness of less than 70 nm, and chosen for among silver and / or gold, a thin blocking layer directly on the metallic functional layer, the layer comprising a metal layer of thickness less than or equal to 5 nm and / or a layer with a thickness less than or equal to 10 nm, which is based on oxide or metal oxynitride or stoichiometric metal nitride, optionally a doped metal oxide protective layer or not selected from zinc oxide, the mixed oxide of tin and zinc, of indium and zinc, an overcoat optionally conducting conductive oxide selected from indium oxide, zinc oxide, tin oxide and / or an overlayer of thickness less than or equal to at 10 nm of sub-stoichiometric oxide selected from molybdenum oxide, nickel oxide, aluminum oxide, titanium oxide, zirconium oxide, tantalum oxide, silicon oxide, silver oxide, gold oxide, platinum, palladium, the etching being carried out in one step and with an acid solution selected from nitric acid HNO3 pure or mixed with hydrochloric acid HCl, or pure hydrochloric acid in or mixture with trichloride of iron

FeCl ₃ .

20. A method of etching a multilayer electrode (3) according to the preceding claim characterized in that the etching is performed in the presence of at least one metal strip current supply preferably in the form of a monolayer based on one of the following metals: Mo, Al, Cr, Nd or alloy such as MoCr, AlNd or a multilayer such as MoCr / Al / MoCr.

21. Organic electroluminescent device (10, 10 ') comprising at least one substrate, in particular glass, with a lower electrode according to one of claims 1 to 18, comprising at least one organic electroluminescent layer on the lower electrode and under a so-called electrode. higher.

22. Organic electroluminescent device (10, 10 ') according to claim 21, characterized in that the device is a single glazing, double glazing or laminated glazing.

23. Organic electroluminescent device (10, 10 ') according to one of claims 21 to 22, characterized in that it comprises a plurality of adjacent organic electroluminescent systems, each emitter of white light or, in series of three, red, green and blue light, the systems being connected in series.

24. The organic electroluminescent device (10, ICC) according to one of claims 21 to 23 characterized in that it forms one or more transparent and / or reflective luminous surfaces, in particular an illuminating, decorative, architectural system, a panel of signaling display, for example of the drawing, logo, alphanumeric signaling type, the system producing uniform light or differentiated light zones, in particular by guided light extraction in the glass substrate.

25. An organic electroluminescent device (10, 10 ') according to one of claims 21 to 24, characterized in that it is: intended for the building, such as an external luminous glazing, an internal light partition or a (part of) luminous glazed door, in particular a sliding door, intended for a transport vehicle, such as a luminous roof, a

(part of) illuminated side window, an internal light partition of a land, water or aerial vehicle, intended for street or professional furniture such as a bus shelter panel, a wall of a display, a jewelery display or a showcase, a wall of a greenhouse, an illuminating slab, intended for interior furnishing, a shelf or furniture element, a cabinet facade, an illuminated slab, a ceiling lamp, an illuminating tablet refrigerator, an aquarium wall, for the backlighting of electronic equipment, including a display or display screen possibly dual screen, such as a television or computer screen, a touch screen, a illuminating mirror, especially for lighting a bathroom wall or a kitchen worktop, or to be a ceiling light.