Classifications

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  • 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
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C17/00—Surface treatment of glass, not in the form of fibres or filaments, by coating
  • C03C17/34—Surface treatment of glass, not in the form of fibres or filaments, by coating with at least two coatings having different compositions
  • C03C17/36—Surface treatment of glass, not in the form of fibres or filaments, by coating with at least two coatings having different compositions at least one coating being a metal
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C17/00—Surface treatment of glass, not in the form of fibres or filaments, by coating
  • C03C17/34—Surface treatment of glass, not in the form of fibres or filaments, by coating with at least two coatings having different compositions
  • C03C17/36—Surface treatment of glass, not in the form of fibres or filaments, by coating with at least two coatings having different compositions at least one coating being a metal
  • C03C17/3602—Surface treatment of glass, not in the form of fibres or filaments, by coating with at least two coatings having different compositions at least one coating being a metal the metal being present as a layer
  • C03C17/3639—Multilayers containing at least two functional metal layers
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C17/00—Surface treatment of glass, not in the form of fibres or filaments, by coating
  • C03C17/34—Surface treatment of glass, not in the form of fibres or filaments, by coating with at least two coatings having different compositions
  • C03C17/36—Surface treatment of glass, not in the form of fibres or filaments, by coating with at least two coatings having different compositions at least one coating being a metal
  • C03C17/3602—Surface treatment of glass, not in the form of fibres or filaments, by coating with at least two coatings having different compositions at least one coating being a metal the metal being present as a layer
  • C03C17/3644—Surface treatment of glass, not in the form of fibres or filaments, by coating with at least two coatings having different compositions at least one coating being a metal the metal being present as a layer the metal being silver
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C17/00—Surface treatment of glass, not in the form of fibres or filaments, by coating
  • C03C17/34—Surface treatment of glass, not in the form of fibres or filaments, by coating with at least two coatings having different compositions
  • C03C17/36—Surface treatment of glass, not in the form of fibres or filaments, by coating with at least two coatings having different compositions at least one coating being a metal
  • C03C17/3602—Surface treatment of glass, not in the form of fibres or filaments, by coating with at least two coatings having different compositions at least one coating being a metal the metal being present as a layer
  • C03C17/3655—Surface treatment of glass, not in the form of fibres or filaments, by coating with at least two coatings having different compositions at least one coating being a metal the metal being present as a layer the multilayer coating containing at least one conducting layer
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
  • H10K71/00—Manufacture or treatment specially adapted for the organic devices covered by this subclass
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
  • H01L31/02—Details
  • H01L31/0224—Electrodes
  • H01L31/022466—Electrodes made of transparent conductive layers, e.g. TCO, ITO layers
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
  • H10K2102/00—Constructional details relating to the organic devices covered by this subclass
  • H10K2102/10—Transparent electrodes, e.g. using graphene
  • H10K2102/101—Transparent electrodes, e.g. using graphene comprising transparent conductive oxides [TCO]
  • H10K2102/102—Transparent electrodes, e.g. using graphene comprising transparent conductive oxides [TCO] comprising tin oxides, e.g. fluorine-doped SnO2
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
  • H10K2102/00—Constructional details relating to the organic devices covered by this subclass
  • H10K2102/10—Transparent electrodes, e.g. using graphene
  • H10K2102/101—Transparent electrodes, e.g. using graphene comprising transparent conductive oxides [TCO]
  • H10K2102/103—Transparent electrodes, e.g. using graphene comprising transparent conductive oxides [TCO] comprising indium oxides, e.g. ITO
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
  • H10K2102/00—Constructional details relating to the organic devices covered by this subclass
  • H10K2102/301—Details of OLEDs
  • H10K2102/351—Thickness
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
  • H10K71/00—Manufacture or treatment specially adapted for the organic devices covered by this subclass
  • H10K71/831—Aging

Definitions

• the subject of the present invention is a conductive support for an organic light-emitting diode device and an organic light-emitting diode device incorporating it.
• the known organic light emitting diode systems or OLED comprise one or more organic electroluminescent materials electrically powered by electrodes generally in the form of two electroconductive layers surrounding this (s) material (s).
• ITO 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 oxidizing agent of the oxygen type) and their thickness is of the order of 100 to 150 nm.
• this ITO layer has a number of disadvantages. Firstly, the material and the high temperature deposition process (350 ° C) to improve the conductivity generate additional costs. The resistance per square remains relatively high (of the order of 10 ⁇ per square) unless the thickness of the layers is increased beyond 150 nm, which results in a decrease in transparency and in an increase in the roughness surface which is critical for OLEDs.
• new electrode structures are developing using a thin metal layer instead of ⁇ to make OLED devices emitting substantially white light for illumination.
• thin film stacks comprising one or more Silver layers to increase the conductivity of TCO-based anodes is also known.
• an OLED anode comprising both an ITO layer and two silver layers is described in the international application WO2009 / 083693 in the name of the Applicant.
• the anode in the form of a bilayer stack silver comprises in this order:
• an antireflection sublayer of given optical thickness L1 composed of a possible Si 3 N 4 bottom layer, of a first amorphous zinc and zinc tin (SnZnO) smoothing layer, of a first crystalline contact layer of zinc oxide doped with aluminum (AZO),
• a separating layer of given optical thickness L2 composed of an additional AZO layer, a second amorphous SnZnO smoothing layer, and a second AZO contact layer,
• the first smoothing layer of tin and zinc mixed oxide (SnZnO) makes it possible to limit the roughness of the following layers.
• the first AZO contact layer, the additional AZO layer and the second AZO contact layer are thin (5 nm) because of their crystallinity while the amorphous intermediate layer is thick.
• each onblocker forms a protective layer
• the layer which overcomes the silver layer (the first and the second) is deposited using a reactive plasma (oxygen, nitrogen, etc.), for example if the oxide layer which surmounts it is deposited by cathodic sputtering ,
• L1 and L2 optical thicknesses and layer geometrical thicknesses are adjusted to significantly reduce the colorimetric variation depending on the angle of view.
• Table A details the nature, the geometric thickness e and the optical thicknesses L1 and L2 of the various layers of these examples, as well as the main optical and electrical characteristics of the stacks.
• the deposit conditions for each of the layers are as follows:
• the Si 3 N 4 Al layers are deposited by reactive sputtering using an aluminum-doped silicon target at a pressure of 0.25 Pa in an argon / nitrogen atmosphere,
• the layers of SnZnO: Sb are deposited by reactive sputtering using a target of zinc and antimony-doped tin containing, by mass, 65% of Sn, 34% of Zn and 1% of Sb, under a pressure of 0.2 Pa and in an argon / oxygen atmosphere,
• the silver layers are deposited using a silver target, under a pressure of 0.8 Pa in an atmosphere of pure argon,
• the Ti layers are deposited using a titanium target under a pressure of 0.8 Pa in a pure argon atmosphere;
• the AZO layers are deposited by reactive sputtering using an aluminum doped zinc target at a pressure of 0.2 Pa and in an argon / oxygen atmosphere,
• ITO overlayers are deposited using a ceramic target in an argon / oxygen atmosphere, at a pressure of 0.2 Pa and in an argon / oxygen atmosphere.
• the aim of the invention is to provide an efficient OLED device (in terms of luminance homogeneity, and / or luminous efficiency). To do this, the invention provides an electrode which has adequate electrical and optical performance especially after annealing.
• the electrode must also be reliable, that is to say not favoring short circuits.
• the invention firstly relates to a conductive support for OLED device comprising a transparent glass substrate, preferably mineral, carrying, on a first main face, a transparent electrode, called a lower electrode, and which comprises the stacking thin layers next in this order (away from the substrate):
• a first (mono) crystalline contact layer based on zinc oxide, preferably doped, better still which consists essentially of a zinc oxide doped preferably with aluminum and / or with gallium (AZO (A) GZO), said first contact layer is preferably of thickness e c i of less than 15nm, more preferably less than or equal to 10 nm, and preferably at least 3 nm,
• a (mono- or multi) crystalline layer referred to as an additional layer, based on doped zinc oxide, preferably consisting essentially of a zinc oxide doped preferably with aluminum and / or gallium (AZO, (A); ) GZO), of thickness e 2 given, directly on the first layer based on silver,
• doped zinc oxide preferably consisting essentially of a zinc oxide doped preferably with aluminum and / or gallium (AZO, (A); ) GZO
• e 2 thickness
• a possible (mono) amorphous layer referred to as an intermediate layer, based on zinc tin oxide (Sn x Zn y O, more simply called SnZnO) optionally doped (for example Sb) or based on oxide of indium and zinc (called IZO), or based on indium, zinc and tin oxide (called ITZO) of thickness e, given, preferably directly on the additional layer,
• Sn x Zn y O more simply called SnZnO
• Sb zinc tin oxide
• IZO oxide of indium and zinc
• ITZO indium, zinc and tin oxide
• a second (mono) crystalline contact layer based on zinc oxide preferably doped, preferably consisting essentially of zinc oxide doped preferably with aluminum and / or gallium (AZO, (A) GZO) second contact layer having a thickness e c2 preferably less than 15 nm, better still less than or equal to 10 nm, and preferably at least 3 nm, preferably directly on the intermediate layer,
• a second (mono) metal layer based on silver (preferably silver), with a thickness e.sub.2 given of less than 20 nm, better still less than or equal to 15 nm, and preferably of at least 3 nm and even at least 5 nm, preferably layer directly on the second crystalline contact layer, a so-called overblocking layer, directly on the second silver-based layer, which comprises a metal layer, optionally a nitride and / or metal oxide layer, 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, especially based on an alloy of at least one or two of said materials, of thickness less than 3 nm (or even less than 2 nm), preferably based on (or in) Ti or TiO x ,
• An electroconductive overcoat directly on the preferably dielectric overblocker (at least free of silver) and preferably with a final layer of adaptation of the output work.
• the sum of the thicknesses e C 2 + e 2 is at least 30 nm and better still at least 40 nm or even at least 70 nm,
• the thickness e is less than 15 nm, preferably less than or equal to 10 nm, or even in particular for SnZnO, less than or equal to 8 nm, and preferably e, is at least 3 nm.
• the following is used for the separating layer:
• the first overblocker is neither necessary for the protection of the first silver layer nor for the subsequent chemical protection, but in addition contributes to the creation of roughness in particular for an additional layer AZO or GZO.
• the measurement of the square resistance in the stacks of the aforementioned prior art is performed by a non-contact technique. This method indicates the contribution of the two silver layers assuming zero vertical resistance between the two silver layers.
• the measurement of the square resistance according to another complementary measurement method, known as the four-point method, which measures the effective R squared on a lateral length corresponding to the distance between the tips, (as detailed later) was appropriately selected by the Applicant and the vertical strength of the stacks of the prior art proved to be too high before annealing and especially after annealing performed by the Applicant.
• the Applicant has furthermore identified that in the stacks of the prior art, it is the intermediate layer of tin oxide and of very thick zinc between the two silver layers which is at the origin of the performances of OLED disappointing in terms of luminous efficiency or luminance homogeneity over large sizes, this layer reducing the vertical electrical conductivity of the electrode.
• e C 2 + e 2 is important, the additional layer (mono or multilayer) being preferably thicker than the 5nm in the prior art.
• the optional intermediate layer is removed or at least of sufficiently reduced thickness to maintain a low electrical resistance to better exploit the conductivities of the two Ag layers for the RD.
• one or more dielectric thin layers can be added back into the separator layer as long as the vertical resistance remains sufficiently low.
• the fineness of the intermediate layer makes it possible to lower the resistance by square and / or absorption of the electrode and in particular by not generating dendrites in the silver layers.
• the electrical properties of the stack according to the invention are better than in the prior art in addition to improving the roughness.
• the thin intermediate layer preferably tin oxide and zinc SnZnO, is advantageously used because a layer based on zinc oxide, such as AZO in particular, remains more fragile with respect to chemical procedures, particularly those involving liquid treatments (cleaning, ultrasonic bath etc.).
• this thin intermediate layer according to the invention preferably tin oxide and zinc SnZnO, is then preferably significantly reduced without being zero. Even fine, it provides an acceptable chemical resistance.
• this thin intermediate layer has a function of smoothing, in particular SnZnO, but of a second order, the removal of the first overblocker (and the direct deposition of the crystalline layer based on zinc oxide) being much more important.
• This thin intermediate layer is of a different material, at least from a crystallographic point of view, than that of the second contact layer under which it is preferably directly arranged.
• This thin intermediate layer can be doped with a metal, SnZnO is doped preferably with antimony (Sb).
• this thin intermediate layer preferably chosen from tin oxide and zinc oxide, it is furthermore preferable that it be devoid of indium or at least with a percentage of indium by total weight of metal of less than 10%. or even less than 5%. It is preferred that it consists essentially of tin oxide and zinc.
• the total weight percentage of Sn metal is preferably from 20 to 90% (and preferably from 80 to 10% for Zn) and in particular from 30 to 80% (and preferably from 70 to 20 for Zn), in particular the weight ratio Sn / (Sn + Zn) is preferably from 20 to 90% and in particular from 30 to 80%. And / or it is preferred that the sum of the percentages by weight of Sn + Zn is at least 90% by total weight of metal, more preferably at least 95% preferably and even at least 97%.
• a metal zinc and tin target whose weight percentage (total target) of Sn is preferably from 20 to 90 (and preferably from 80 to 10 for Zn) and in particular from 30 to 80 for Sn (and preferably 80 to 30 for Zn) in particular, the Sn / (Sn + Zn) ratio is preferably from 20 to 90% and in particular from 30 to 80% and / or the sum of the percentages by weight of Sn + Zn of at least 90%, more preferably at least 90% and even at least 95%, or even at least 97%.
• the metal zinc and tin target can be doped with a metal preferentially with antimony (Sb).
• the amorphous intermediate layer may be alternatively based on IZO, the weight percentage (total metal) of In is preferably at least 40%, even at least 60%, and preferably up to 90% and / or the sum of the percentages by weight of In + Zn of at least 85% by total weight of metal or even at least 90% preferably and even at least 95%.
• the amorphous intermediate layer IZO may be doped with aluminum (called IAZO) and / or gallium (called IGZO).
• the weight percentage (total metal) of In is preferably at least 40% even 60%, and Ga / (Ga + Zn + 1n) ⁇ 10% by weight.
• the weight percentage (total metal) of In is preferably at least 40% even 60%, and Al / (Ga + Zn + ln) ⁇ 10% by weight.
• the percentage by weight is at least 2% for Zn and the sum of the percentages by weight of Sn + ln of at least 90% by total weight of metal or even at least 95% by weight. % preferably and even at least 98%.
• At least 60%, preferably at least 80%, of the thickness of the separating layer is formed of the thickness e 2 and / or e 2 is greater than or equal to 35 nm, greater than or equal to 45nm, and better than or equal to 60nm.
• the intermediate layer is preferably present.
• This choice gives the freedom in particular to have as close to the second silver-based layer the thin intermediate layer, preferably SnZnO, to further increase the chemical resistance if necessary.
• the additional crystalline layer consists essentially of doped zinc oxide aluminum and / or gallium (GZO or A (G) ZO) and preferably the second crystalline contact layer consists essentially of doped zinc oxide, preferably aluminum and / or gallium (GZO or A (G) ZO), by example of thickness e c2 less than or equal to 10 nm, and preferably at least 3 nm when the thin intermediate layer, preferably based on SnZnO, is inserted.
• layers which are devoid of indium or at least with a percentage of indium by total weight of metal of less than 10% or even 5% are particularly preferred.
• a doped ZnO oxide preferably Al (AZO) and / or Ga (GZO) with the sum of the percentages by weight of Zn + Al or Zn + Ga or Zn + Ga + Al or Zn + another dopant preferably chosen from B, Se, or Sb or else from Y, F, V, Si, Ge, Ti, Zr, Hf and even by In which is at least 90% by total weight of better metal at least 95% and even at least 97%.
• These two layers are preferably of identical nature (made with the same target for example) and even of identical thickness preferably.
• ZnO oxide doped with preferably Al (AZO) and / or Ga (GZO or AGZO) with the sum of the percentages by weight of Zn + Al or Zn + Ga (or Zn + Ga + Al) or Zn + other dopant preferably chosen from B, Se , or Sb or else from Y, F, V, Si, Ge, Ti, Zr, Hf and even by In of at
• the additional layer is preferably identical to the first and / or the second contact layer, for the sake of simplification.
• an AZO layer according to the invention contact layer or additional layer
• the percentage by weight of aluminum on the sum of the percentages by weight of aluminum and zinc in other words AI / (AI + Zn), less than 10%, preferably less than or equal to 5%.
• a ceramic target of aluminum oxide and zinc oxide such that the percentage by weight of aluminum oxide on the sum of the percentages by weight of zinc oxide and of aluminum oxide, typically Al 2 O 3 / (Al 2 O 3 + ZnO), is less than 14%, preferably less than or equal to 7%.
• a layer of GZO according to the invention (layer of contact and / or additional layer) that the percentage by weight of gallium on the sum of the percentages by weight of zinc and gallium, in other words Ga / (Ga + Zn) is less than 10% and preferably less than or equal to 5% .
• a zinc oxide and gallium oxide ceramic target such as the percentage by weight of gallium oxide on the sum of the weight percentages of zinc oxide and gallium oxide, typically Ga 2 0 3 (Ga 2 O 3 + ZnO) is less than 1 1%, preferably less than or equal to 5%.
• the additional layer of zinc oxide which may be particularly thick, be deposited from a zinc oxide ceramic target (preferably) Al and / or Ga - more precisely containing zinc, aluminum oxide and / or gallium oxide -, in a noble gas atmosphere (preferably Ar) and optionally mixed with oxygen in a small amount, preferably such as the ratio 0 2 / (noble gas (s) +0 2 ) is less than 10% and even better than or equal to 5%, usually less than that used in reactive sputtering with a zinc metal target.
• a noble gas atmosphere preferably Ar
• oxygen preferably such as the ratio 0 2 / (noble gas (s) +0 2 ) is less than 10% and even better than or equal to 5%, usually less than that used in reactive sputtering with a zinc metal target.
• the second contact layer and even the first contact layer be deposited from a (even) zinc oxide ceramic target doped (preferably) Al and / or Ga - more precisely containing oxide zinc oxide, aluminum oxide and / or gallium oxide - in a noble gas atmosphere (preferably Ar) and optionally mixed with oxygen in a small amount, preferably such as the ratio of 0 2 / (noble gas (s) +0 2 ) is less than 10% and even better than or equal to 5%, usually less than that used in reactive sputtering with a zinc metal target.
• a (even) zinc oxide ceramic target doped preferably) Al and / or Ga - more precisely containing oxide zinc oxide, aluminum oxide and / or gallium oxide - in a noble gas atmosphere (preferably Ar) and optionally mixed with oxygen in a small amount, preferably such as the ratio of 0 2 / (noble gas (s) +0 2 ) is less than 10% and even better than or equal to 5%, usually less than that used in reactive sputtering with a
• n1 is the average index defined by the sum of the products index or by thickness e, the layers divided by the sum of thicknesses e, respectively, according to the classical formula ⁇ 1
• a layer is dielectric as opposed to a metal layer, typically is metal oxide and / or metal nitride, including silicon by extension. It may be an organic layer, but a mineral layer is preferred.
• a layer is said to be amorphous in the sense that it can be completely amorphous or partially amorphous and thus partially crystalline, but that it can not be completely crystalline throughout its thickness.
• layer in the sense of the present invention, without precision, it should be understood that there may be a layer of a single material (monolayer) or more layers (multilayer), each of a different material.
• the defined material layers are monolayers.
• the thickness corresponds to the geometrical thickness.
• the electrode according to the invention can extend over a large surface, for example an upper surface or equal to 0.02 m 2, or even greater than or equal to 0.5 m 2 or greater than or equal to 1 m 2.
• the lower electrode is composed of thin layers and therefore layers of thickness each less than 150 nm.
• the total thickness of the stack of the electrode is less than 300 nm and even 250 nm.
• a layer based on metal oxide (s) given (s), the expression "base” preferably means that the proportion by weight of (s) element (s) The specified metal (s) is at least 50% by total weight of metal and preferably at least 60%.
• a nitride-based layer of metal element (s) given (s), the expression based preferably means that the proportion by weight of (s) element (s) specified metal (s) is at least 50% by total weight of metal and preferably at least 60%.
• Oxide or nitride is preferably meant to exhibit a presence of the metal dopant in less than 10% by total weight of metal in the layer.
• a layer consisting essentially of an oxide of one or more given metallic elements and optionally defined metal dopants, the sum of the percentages by weight of said elements and optional dopants mentioned is preferably greater than 90. % by total weight of metal and even 95% or even 98%.
• a layer consisting essentially of a nitride of one or more given metallic elements and optionally defined metal dopants, the sum of the percentages by weight of said elements and optional dopants mentioned is preferably greater than 90. % by total weight of metal and even 95% or even 98%.
• metal or (element or dopant) metal includes silicon and boron, this in addition to all the metallic elements of the periodic table (alkaline, alkaline earth, transition, poor metals).
• a layer which consists essentially of a given material may comprise other elements (impurities, ...) as long as they do not significantly modify the desired properties of the layer typically by their small amount.
• a layer made of a material is synonymous with a layer consisting essentially of this material.
• indium tin oxide or tin-doped indium oxide or ITO (for the English name: Indium tin oxide) means a mixed oxide or a mixture obtained from indium (III) (ln 2 O 3 ) and tin (IV) oxides (SnO 2 ), preferably in proportions by weight of between 70 and 95% for the first oxide and 5 to 20% by weight for the first oxide; A preferred range of proportions is 85 to 92% by weight of In 2 0 3 and 8 to 15% by weight of SnO 2.
• the ITO-based topcoat does not include any other oxide. metal or less than 10% by weight of oxide on the total weight.
• thin layer is understood to mean a layer of thickness less than 10 nm.
• the invention does not apply only to stacks comprising only two "functional" silver layers, arranged between three coatings, two of which are underlying coatings. It also applies to stacks comprising three functional silver layers alternating with four coatings, three of which are underlying coatings, or four silver functional layers alternating with five coatings, four of which are underlying coatings.
• the underlayer may have at least one of the following characteristics:
• the substrate preferably a mineral glass sheet
• optical index (average) greater than equal to 1.7, even at 1.8, in particular for a substrate of optical index around 1.5,
• At least the first sub-layer is a metal oxide, or all the layers of the overcoat are made of metal oxide (excluding sub-blocker),
• At least the first underlayer is a metal nitride
• the underlayer is devoid of indium, or at least does not comprise a layer of IZO, ITO,
• oxides such as niobium oxide (such as Nb 2 O 5 ), zirconium oxide (such as Zr0 2 ), alumina (such as Al 2 O 3 ), tantalum oxide (such as Ta 2 O 5 ), tin oxide (such as SnO 2 ), or silicon nitride (Si 3 N 4 ).
• the underlayer comprises a first sub-layer, preferably as a bottom layer, which is an oxide layer (more preferably amorphous) and preferably chosen from one of the following layers:
• a layer based on a mixed oxide of tin and zinc (SnZnO, more precisely Sn x Zn y O), preferably amorphous, for example doped preferably Sb, and preferably consists essentially of mixed oxide of tin and zinc, of thickness e 0 preferably greater than 20 nm, preferably 30 to 50 nm,
• TiOx preferably TiO 2
• TiOx preferably TiO 2
• TiOx preferably TiO 2
• TiOx preferably TiO 2
• TiOx preferably TiO 2
• TiOx preferably TiO 2
• niobium oxide for example Nb 2 0 5
• niobium oxide for example Nb 2 0 5
• a layer based on niobium oxide preferably consisting essentially of a layer of niobium oxide (optionally doped) which also has the advantage of being an optical index layer; greater than 2.2, of thickness e 0 preferably greater than 10 nm, preferably 20 to 40 nm.
• the weight percentage (total metal) of Sn is preferably from 20 to 90% (and preferably from 80 to 10% for Zn) and in particular from 30 to 80%, especially Sn / (Sn + Zn) weight ratio is preferably from 20 to 90% and in particular from 30 to 80%. And / or it is preferred that the sum of the percentages by weight of Sn + Zn is at least 90% by total weight of metal, more preferably at least 95% preferably and even at least 97%.
• the first sub-layer of SnZnO is a layer preferably of stoichiometry identical to the thin SnZnO intermediate layer.
• a multilayer can be formed with a layer zinc oxide and tin oxide, a niobium oxide layer or a titanium oxide layer, but it is preferred to choose only one of these layers under the first contact layer.
• the first underlayer especially if it is the bottom layer can form an alkali barrier (if necessary) and / or an etch stop layer (s) when the electrode is or is to be divided into a plurality of zones (active).
• the etch stop layer is used in particular to protect the substrate in the case of chemical etching or reactive plasma etching.
• the electrode according to the invention does not have an amorphous layer of zinc oxide and tin or an amorphous layer of titanium oxide with a thickness of at least 20 nm or even 40 nm directly under the first contact layer.
• the first underlayer of oxide in particular to prevent the formation of dendrites and / or lower (more) the resistance by square and the absorption after annealing, is underlying a layer called barrier (dendrites) which is in contact with the first under layer, preferably directly under the first crystalline contact layer.
• the barrier layer is:
• SiN x silicon nitride (SiN x , in particular Si 3 N 4 ) and optionally SiZrN zirconium to increase the refractive index, preferably doped layer, in particular aluminum,
• SiO x silica
• SiO 2 silica
• silicon oxynitride Si x O y N or optionally silicon oxynitride Si x O y N, or even silicon oxycarbonitride
• AlN aluminum nitride
• the insertion of the thin barrier layer directly on the first underlayer of oxide and preferably directly under the first contact layer still allows good growth and sufficient smoothing of the first contact layer, whereas the use of a smoothing layer in SnZnO directly under the AZO contact layer, instead of the Si 3 N 4 layer, was considered essential in the aforementioned prior art.
• the thickness e b of the barrier layer is less than 15 nm, preferably less than or equal to 10 nm, and even 9 nm, preferably 3 to 8 nm. For silica this limits the impact of its low optical index.
• the sub-layer is then preferably three-layer and in particular the following three-layer: (SnZnO or TiO x optionally doped) / Si (Zr) N or SiO 2 (optionally doped) / AZO or (A) GZO.
• the barrier layer consists essentially of silicon nitride and possibly zirconium or silica and is optionally doped, in particular Si (Zr) AlN or SiAlO.
• the barrier layer is more preferably essentially composed of a layer of silicon nitride which is preferably doped, preferably with aluminum, or with a layer of preferably doped silicon nitride and zirconium, preferably with aluminum.
• the silicon nitride is deposited by reactive cathodic sputtering from a metal target (Si) using nitrogen as a reactive gas.
• Aluminum is preferably present in the (Si) target in relatively large amounts, generally ranging from a few percent (at least 1%) to 10% or more by total weight of metal, typically up to 20%, ranging from beyond a conventional doping, intended to confer on the target a sufficient conductivity.
• an aluminum-doped silicon nitride barrier layer preferably comprises a percentage by weight of aluminum over the weight percentage of silicon and aluminum, hence Al / (Si + Al), ranging from 5% to 15%.
• Aluminum doped silicon nitride corresponds more exactly to a silicon nitride comprising aluminum (SiAIN).
• a barrier layer of aluminum-doped silicon nitride and zirconium corresponds more exactly to a silicon and zirconium nitride comprising aluminum.
• the weight percentage of zirconium in the barrier layer may be from 10 to 25% by total weight of metal.
• the sum of the percentages by weight of Si + Al or Si + Zr + Al is at least 90% by total weight of metal, or even preferably 95% by weight or even at least 99%.
• the barrier layer is alternately essentially composed of a layer of silica and optionally preferably doped zirconia, preferably with aluminum.
• the silica is deposited by reactive sputtering from a metal target (Si), preferably doped with oxygen as a reactive gas.
• an aluminum-doped silicon oxide barrier layer preferably comprises a percentage by weight of aluminum over the weight percentage of silicon and aluminum, hence Al / (Si + Al), ranging from from 5% to 15%. Silicon oxide doped with aluminum corresponds more exactly to a silicon oxide comprising aluminum.
• the sum of the percentages by weight of Si + Al or Si + Zr + Al is at least 90% by total weight of metal, or preferably at least 95% or even at least 99%.
• silicon nitride (and possibly zirconium) or silica, possibly with zirconia, even in thin thickness, can play a protective role and effectively reduce, or even eliminate, the formation of dendrites generated by the underlying thick layer of SnZnO , without its presence leading to a degradation of the electrical and optical properties of the electrode before and after annealing.
• the presence of the thin layer of silicon nitride or silica does not have a significant impact on the roughness (measured by AFM on 5 ⁇ m x 5 ⁇ ) of the electrode.
• the required thickness of the barrier layer to reduce or prevent the formation of dendrites generated by the SnZnO thick film, and to improve the optical and electrical properties increases with the temperature and the duration of the annealing. For annealing temperatures below 450 ° C and annealing times of less than 1 hour, layer thicknesses below 15 nm appear to be sufficient.
• a layer based on silicon nitride (Si 3 N 4 ) and optionally zirconium preferably doped preferentially to aluminum is the first thin layer of this underlayer, preferably directly on the transparent substrate and preferably directly on the first contact layer, of thickness e 0 greater than 20 nm, better than or equal to 30 nm .
• This first layer is preferably essentially composed of silicon nitride and optionally zirconium, and as already described for the barrier layer, an aluminum doped silicon oxide.
• the sum of the percentages by weight of Si + Al or Si + Zr + Al is at least 90% by total weight of metal, preferably 95% or even at least 99% by weight. %.
• the dielectric underlayer is then preferably a Si (Zr) N / AZO or (A) GZO bilayer and even more preferably Si (Zr) N doped with AI / AZO or (A) GZO.
• Silicon nitride is very fast to deposit, forms an excellent alkali barrier and can serve as an etch stop layer.
• the silicon nitride contains zirconium, it is known that its refractive index increases, for example up to 2.2 or even 2.3 depending on the zirconium content. Also we can adjust its thickness depending on the refractive index and naturally reduce its thickness compared to a SiAIN.
• the first and / or second contact layers may preferably be doped zinc oxide, preferably Al (AZO), Ga (GZO), or B, Se, or Sb, or alternatively Y , F, V, Si, Ge, Ti, Zr, Hf and even by In to facilitate deposition and a lower electrical resistivity.
• a first and / or second crystalline zinc majority contact layer containing a very small amount of tin which can be likened to doping hereinafter referred to as Zn a Sn b O, preferably with the ratio of weight following Zn / (Zn + Sn)> 90%, better still ⁇ 95%.
• Zn a Sn b O a very small amount of tin which can be likened to doping
• Zn a Sn b O preferably with the ratio of weight following Zn / (Zn + Sn)> 90%, better still ⁇ 95%.
• such a layer with a thickness of less than 10 nm is preferred.
• the thickness of the first contact layer (AZO, GZO, Zn a Sn b O ) is preferably greater than or equal to 3 nm, or even greater than or equal to 5 nm and may also be less than or equal to 20 nm, and still more preferably less than or equal to 10 nm.
• the thickness of the second contact layer (AZO, GZO, Zn Sn b O ) is also greater than or equal to 3 nm, even greater than or equal at 5 nm and may further be less than or equal to 20 nm, and even more preferably less than or equal to 10 nm.
• crystalline layers are preferred to amorphous layers for better crystallization of silver. It is preferentially provided under the first layer of silver (without specifying the possible doping for the layers other than the contact layers):
• first sub-layer Si Zr N / first contact layer AZO or (A) GZO,
• first amorphous sub-layer SnZnO of at least 20 nm / barrier layer Si (Zr) N or SiO 2 / first contact layer Zn a Sn b O,
• first sub-layer Ti (Zr) O preferably at least 10 nm / barrier layer Si (Zr) N or SiO 2 / first contact layer AZO or (A) GZO, first underlayer or Ti (Zr) 0 preferably at least 10 nm / barrier layer Si (Zr) N or SiO 2 / first contact layer Zn a Sn b O, first underlayer or Si (Zr) N at least 20 nm / SnZnO amorphous thickness less than 10nm / first AZO contact layer or (A) GZO
• first sub-layer Nb 2 0 5 preferably at least 20 nm / preferably barrier layer Si (Zr) N x or SiO 2 / first contact layer AZO or (A) GZO,
• first sub-layer Nb 2 0 5 preferably at least 20 nm (/ Si (Zr) N x or SiO 2 / first contact layer Zn to Sn b O,
• first oxide sub-layer preferably at least 20 nm / preferably Si (Zr) N) or SiO 2 / first AZO contact layer or (A) GZO or even ZnO doped B, Se layer; , or Sb or
• the barrier layer being less than 15 nm and even preferably less than 10 nm;
• the separating layer may have at least one of the following characteristics:
• optical index (average) greater than equal to 1, 7, even at
• the majority, or even all of the layers forming the separating layer have an optical index greater than 1, 7, even at 1.8, the separating layer is devoid of indium, or at least does not include layer in IZO, ITO.
• the multiplicity of similar layers can decrease the roughness.
• the separating layer comprises (and even consists of) successively, preferably after (without further layers between them) the additional layer which is zinc oxide doped with aluminum and / or gallium, the thin amorphous intermediate layer which is tin oxide and zinc oxide (optionally doped with Sb in particular), preferably of thickness e, less than or equal to 8 nm and at least 3 nm, the second contact layer which is zinc oxide doped with aluminum and / or gallium, preferably with the sum of the thicknesses e C 2 + e 2 of at least 50 nm, better still at least 70 nm and less than 120 nm, and preferably the separating layer comprises (and even consists of ) AZO / SnZnO / AZO or GZO / SnZnO / GZO preferably with the sum of the thicknesses e C 2 + e 2 of at least 50 nm, better still at least 70 nm and less than 120 nm.
• one or more other amorphous layers each of thickness e u less than 15 nm, better at 10 nm, divide the (multi) additional layer into several layers called (mono) buffer layers (At least one or even two buffer layers and preferably less than five buffer layers) each of thickness e 2i (distinct or equal) preferably layers evenly spaced from each other.
• Each other amorphous layer being based on the same oxide as that of the intermediate layer and preferably mixed zinc oxide and optionally doped tin.
• ⁇ e 2i the sum of the thicknesses of the buffer layers forming the additional layer, ⁇ e 2i is equal to e 2 , and the relation e c2 + e 2 corresponds more precisely to e c2 + ⁇ e 2i .
• the other amorphous layer (s), preferably of SnZnO, are preferably identical in nature to the amorphous, preferably SnZnO, layer.
• the separating layer is a crystalline monolayer (directly on the first silver layer) and preferably consists essentially of doped zinc oxide, preferably aluminum and / or gallium, e 2 being preferably at least 50 nm, better still at least 70 nm and still more preferably at least 80 nm and preferably less than 120 nm. Said monolayer thus forms both the additional layer and the second contact layer.
• the separating layer according to the invention has a sufficiently low vertical resistance between the two silver layers.
• each layer (other than the optional thin intermediate layer) is of electrical resistivity less than or equal to 10 3 ohm.cm, preferably less than or equal to 1 ohm . cm or even less than or equal to 10 "2 ohm cm.
• a suitably doped zinc oxide layer has a sufficiently low vertical resistance, which is important for the additional layer and the second contact layer.
• a layer of doped zinc oxide and especially a layer of AZO or GZO has a low vertical electrical resistance even at thicknesses beyond 50 nm.
• an AZO layer has a resistivity of 10 "2 Ohm. Cm, or even 10" 3 Ohm. cm or even down to 10 "4 Ohm cm depending on the method of deposition and post-treatments, as evidenced by the article entitled” Transparent conducting oxide semiconductors for transparent electrodes "Semicond Sci Technol 20 (2005) S35-S44.
• a layer of ITO typically has a resistivity of 210 "
• Zn a Sn b O zinc oxide, predominant in zinc, and containing a very small amount of tin which can be likened to doping, hereinafter referred to as Zn a Sn b O, preferably with weight ratio according to Zn / (Zn + Sn)> 90%, more preferably ⁇ 95%.
• the additional crystalline layer may be a zinc oxide "doped" with Sn and / or indium, that is to say containing tin and / or indium.
• the RD of the electrode can be measured by the contactless method, of the electromagnetic type, here called Rn e im- This measurement technique allows to measure the conductivity of the two layers of Ag (or N> 2 silver layers) independently of the conductivity of the separating layer. This method is that used in the prior art.
• the RD is further measured by the 4-point method, called Ra 4p with a distance between points of 3 millimeters, even though the lateral distance of an OLED is usually at least 5 to 10cm. If the vertical resistance between the two layers of Ag is large in front of the lateral resistance between the measuring tips, in contact with the surface of the ITO layer, Ra 4p is greater than Rn e
• the electrode according to the present invention in particular comprising only two layers of silver, an absolute difference of Ra 4p - Rn e im below 0,7xRD e i m preferably less than 0 , 4xRD e i m and even less than 0.2xRD e i m , Rcieim being the measurement by the electromagnetic non-contact method (Nagy instrument for example) and RD 4p being the measurement by the 4-point method (Napson instrument for example) with a distance of 3mm between the points.
• the vertical resistance must be the same. weaker possible, because it induces an increase in the power required to deliver, and therefore a drop in luminous efficiency (Im / W).
• the substrate according to the invention coated with the lower electrode has a low roughness (overcoat).
• the substrate according to the invention coated with the lower electrode preferably has, on the overlayer, a roughness R q , a well-known parameter, less than or equal to 5 nm, better still 3 nm, preferably even less than or equal to 2 nm, in order to avoid spike effects that drastically reduce the lifetime and reliability of the OLED.
• the substrate according to the invention coated with the lower electrode has, preferably, on the overlayer a roughness R max , known per se, less than or equal to 20 nm, preferably even less than or equal to 15 nm.
• the parameters can be measured in different ways, preferably by atomic force microscopy. The measurement is generally on 1 to 30 microns square by atomic force microscopy.
• the absorption or roughness and / or limit the vertical resistance and / or avoid dendrites to the maximum or to promote the injection of current and / or limit the value of the operating voltage, it avoids the presence of certain layers of oxides or nitrides.
• the first silver layer (below the second layer and / or above the second layer) one or more layers based on silicon nitride, silicon oxide, silicon oxynitride, silicon oxycarbide, based on silicon oxycarbonitride, or based on titanium oxide with a thickness greater than or equal to 15 nm or even greater than 10 nm.
• the present invention does not include multilayer structures whose last layer (the outermost layer) is a non-conductive layer, such as a silicon carbide layer, or preferably at least one non-conductive layer. conductive thick enough to prevent vertical conduction of silver to the layer containing an organic electroluminescent substance. Indeed, such structures would be inappropriate for use as an OLED electrode.
• the overlay may have at least one of the following characteristics:
• At least the first layer (excluding the overblocker) is a metal oxide, or all the layers of the overcoat are made of metal oxide,
• all the layers of the overlayer have a thickness of less than or equal to 120 nm or even 80 nm,
• the overlayer is preferably based on thin layer (s), in particular mineral (s).
• the overlayer is made of layer (s) (excluding fine blocking layer described later) of electrical resistivity less than or equal to 10 2 ohm.cm, preferably less than or equal to 1 ohm. cm or even less than or equal to 10 "2 ohm cm.
• the overlayer is preferably free of layer (s) with a thickness greater than 10 nm or even 5 nm based on silicon nitride (Si 3 N 4 ) or silica-based (SiO 2 ). We can also avoid any etch stop layer by its nature or its thickness (Ti0 2 , Sn0 2 ).
• the overcoat according to the invention is preferably based on at least one of the following metal oxides, optionally doped: tin oxide, indium oxide, zinc oxide (optionally substoichiometric), oxide molybdenum, tungsten, vanadium.
• This overlayer may in particular be tin oxide optionally doped with F, Sb, or zinc oxide optionally doped with aluminum, or may be optionally based on a mixed oxide, especially a mixed oxide of indium and aluminum oxide.
• tin (ITO) a mixed oxide of indium and zinc (IZO), a mixed oxide of zinc and tin SnZnO.
• This overlayer in particular for ⁇ , ⁇ (last layer generally) or based on ZnO, may preferably have a thickness e 3 less than or equal to 100 nm, or 80 nm, for example between 10 or 15 nm and 60 nm.
• the ITO layer is preferentially over-stoichiometric in oxygen to reduce its absorption (deposited under oxygen-rich conditions).
• the last silver-based layer (which is preferably the second) is covered with an additional thin film having a higher work output than silver, typically ITO.
• An adaptation layer of the output work can have for example an output work Ws from 4.5 eV and preferably greater than or equal to 5 eV.
• the overlayer comprises, preferably in the last layer, in particular an adaptation layer of the output work, a layer which is based on (preferably essentially consisting of) at least one of the following metallic oxides optionally doped: indium oxide, zinc oxide optionally sub-stoichiometric, molybdenum oxide (MoO 3 ), tungsten oxide (WO 3 ), vanadium oxide (V 2 O 5 ) , indium oxide and tin (ITO), indium zinc oxide (IZO), or zinc oxide and tin SnZnO, and the overcoat preferably has a thickness less than or equal to 50 nm or even 40 nm or even 30 nm.
• MoO 3 molybdenum oxide
• WO 3 tungsten oxide
• V 2 O 5 vanadium oxide
• ITO indium oxide and tin
• IZO indium zinc oxide
• SnZnO zinc oxide and tin SnZnO
• the overlay may comprise a final layer, which is based on a thin metallic layer (less conductive than silver), in particular based on nickel, platinum or palladium, for example with a thickness of less than or equal to 5 nm, especially of 1 to 2 nm, and preferably separated from the second silver metal layer (or overblocker) by a single layer of simple or mixed metal oxide such as zinc oxide and tin (SnZnO) or ZnO or even ⁇ .
• a thin metallic layer less conductive than silver
• nickel, platinum or palladium for example with a thickness of less than or equal to 5 nm, especially of 1 to 2 nm, and preferably separated from the second silver metal layer (or overblocker) by a single layer of simple or mixed metal oxide such as zinc oxide and tin (SnZnO) or ZnO or even ⁇ .
• the overlayer may comprise, in the last dielectric layer, a layer with a thickness of less than 5 nm or even 2.5 nm and at least 0.5 nm or even 1 nm chosen from a nitride, an oxide, a carbide, an oxynitride and an oxycarbide. Ti, Zr, Ni, NiCr.
• ITO, MoO 3 , WO 3 , V 2 O 5 or even IZO are preferred as the last, and even the only layer of the overlayer .
• the lower electrode according to the invention is easy to manufacture, in particular by choosing materials for the stack which can be deposited at ambient temperature. Even more preferably, most or all of the layers of the stack are deposited under vacuum (preferably successively), preferably by cathodic sputtering possibly assisted by magnetron, allowing significant productivity gains.
• a stack comprising only two (pure) silver layers, the three-layer separating layer, and the one or two-layer overlayer are preferred.
• the overblocker forms a protective layer or even a "sacrificial" layer which makes it possible to prevent the metal layer (the second) from being metalized, in particular in one and / or the other of the following configurations:
• the layer which overcomes the metal layer (the second) 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 that overcomes the metal layer (the second) is likely to vary during industrial manufacture (evolution of the deposition type conditions of a target etc.) especially if the stoichiometry of an oxide-type layer and / or nitride evolves, then modifying the quality of the metal layer and therefore the properties of the electrode (square resistance, light transmission, etc.),
• This protective layer significantly improves the reproducibility of the electrical and optical properties of the electrode. This is very important for an industrial approach where only a low dispersion of electrode properties is acceptable.
• the overblocker may consist of a layer based on niobium, tantalum, titanium, chromium or nickel or an alloy from at least two of said metals, such as a nickel-chromium alloy.
• the metal-based surblocker 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).
• This type of layer based on at least one metal has a particularly important effect of entrapment ("getter" effect).
• the onblocker can be easily manufactured without altering the metal layer (the second).
• 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.
• the metal overblocker it is necessary to limit the thickness of the metal layer and therefore the light absorption to maintain a sufficient light transmission for the transparent electrodes.
• the overblocker can be partially oxidized. This layer is deposited in non-metallic form and is thus 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 MNO x for an oxide of two materials M and N (or more).
• M represents the material
• x is a number less than the stoichiometry of the oxide of the material or type MNO x for an oxide of two materials M and N (or more).
• TiO x , NiCrO x may be mentioned.
• x is preferably between 0.75 and 0.99 times the normal stoichiometry of the oxide.
• the overblocker 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 onblocker can be partially nitrided. It is therefore not deposited in stoichiometric form, but in sub-stoichiometric 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 times and 0.99 times the normal stoichiometry of nitride.
• the overblocker can also be partially oxynitrided.
• the oxidized and / or nitrided surblocker can be easily manufactured without altering the silver layer. It is preferably deposited from a ceramic target, in a non-oxidizing atmosphere preferably consisting of noble gas (He, Ne, Xe, Ar, Kr).
• a non-oxidizing atmosphere preferably consisting of noble gas (He, Ne, Xe, Ar, Kr).
• the overblocker may preferentially be nitride and / or substoichiometric oxide for even more reproducibility of the electrical and optical properties of the electrode.
• the overblocker may have an oxidation gradient, for example M (N) O xi with x, variable, the part of the blocking layer in contact with the metal layer is less oxidized than the part of this layer furthest from the metal layer using a special deposition atmosphere.
• the overblocker is very particularly made of titanium (Ti, TiO x ) which alone protects the silver layers during the manufacturing steps of the OLED and absorbs little after heat treatment.
• subblocking coating or subblockers, arranged directly on the first and / or the second silver-based metal layer, for example those mentioned above for the onblocker.
• the undercoating coating underlying a metal layer towards the substrate is a bonding, nucleation and / or protection coating.
• the first and / or second metal layer may be silver alloy or doped with at least one other material, preferably chosen from: Au, Pd, Al, Pt, Cu, Zn, Cd, In, Si, Zr , Mo, Ni, Cr, Mg, Mn, Co, Sn, in particular is based on of a silver alloy and palladium and / or gold and / or copper, to improve the moisture resistance of silver.
• at least one other material preferably chosen from: Au, Pd, Al, Pt, Cu, Zn, Cd, In, Si, Zr , Mo, Ni, Cr, Mg, Mn, Co, Sn, in particular is based on of a silver alloy and palladium and / or gold and / or copper, to improve the moisture resistance of silver.
• the first and second silver layers can be in the same silver material with the same alloy or doping eventual.
• the first and second silver-based metal layers i.e., pure silver or metal alloy containing predominantly silver
• the first and second silver-based metal layers i.e., pure silver or metal alloy containing predominantly silver
• the thickness e ag i is less than or equal to 15 nm, more preferably less than or equal to 13 nm, preferably from 5 to 10 nm,
• the thickness e ag 2 is less than or equal to 15 nm, better than or equal to 13 nm, preferably from 5 to 10 nm,
• the thickness e ag i is greater than the thickness e 2 (from 1 to 10 nanometers), the thickness e ag 2 is greater than the thickness e ag i (from 1 to 10 nanometers).
• the judicious choice of the L1 and L2 optical thicknesses first makes it possible to adjust the optical cavity in order to optimize the efficiency of the OLED and also to significantly reduce the colorimetric variation as a function of the angle of observation.
• L1 ranges from 100 nm to 120 nm
• L 2 ranges from 140 nm to 240 nm, and even to 220 nm
• the thicknesses ag i + e ag 2 of the first and second metal layers is less than or equal to 30 nm, and preferably less than or equal to 25 nm or even less than or equal to 20 nm to reduce the absorption.
• the lower electrode may preferably be directly on the substrate, the electrode substrate being devoid of internal light extraction element.
• the electrode substrate may comprise an external light extraction element already known per se, such as:
• the increase in the thickness of the additional layer as for it can also allow to obtain a sufficient thickness L2.
• first (preferably amorphous) oxide-based layer preferably at least 20nm / barrier layer / first ZnO (doped) / Ag / / additional crystalline layer ZnO (doped) / amorphous intermediate layer / second ZnO (doped) / Ag / onblocker / overcoat contact layer, preferably ITO, MoO 3 , WO 3 , V 2 0 5 , or even AZO or Zn a Sn b O, optionally topped with a layer (TiN 3) not more than 5nm, better not more than 3nm or 2nm,
• first amorphous sub-layer SnZnO of at least 20 nm / barrier layer / first ZnO contact layer (doped) / Ag / additional doped ZnO crystalline layer (/ amorphous intermediate layer); second doped ZnO contact layer / Ag / onblocker / overcoat preferably ITO, Mo0 3 , WO 3 , V 2 0 5 or AZO or ZnaSnbO (crystalline), possibly topped with a layer (TiN ...) of at most 5nm, better not more than 3nm or 2nm,
• first amorphous sub-layer Ti (Zr) O preferably at least 10 nm / barrier layer / first ZnO (doped) / Ag / added crystalline layer doped ZnO (/ amorphous interlayer /) second contact layer ZnO doped / Ag / onblocker / overcoat preferably ITO, Mo0 3 , W0 3 , V 2 0 5 or AZO or ZnSnO (crystalline), possibly topped with a layer (TiN ...) of at most 5nm, better to at most 3nm or 2nm,
• the stack consists of one of the following stacks (with optional doping not reprecised for the layers other than the contact layers):
• first amorphous oxide sub-layer of at least 20 nm / Si (Zr) N or SiO 2 / first AZO contact layer or (A) GZO / Ag / additional AZO or crystalline layer (A) GZO / amorphous intermediate layer / second AZO contact layer or (A) GZO / Ag / onblocker / overcoat preferably ITO, MoO 3 , WO 3 , V 2 0 5 or AZO or ZnSnO (crystalline), optionally topped with a layer (TiN ...) of at most 5nm, better not more than 3nm or 2nm,
• first amorphous sub-layer SnZnO preferably at least 20 nm / barrier layer Si (Zr) N or SiO 2 / first contact layer AZO or (A) GZO / Ag / additional crystalline layer AZO or (A) GZO / amorphous intermediate layer / second AZO contact layer or (A) GZO / Ag / overblocker / overcoat, preferably ITO, MoO 3 , WO 3 , V 2 O 5 or even AZO or ZnSnO (crystalline), optionally topped with a layer (TiN ...) of not more than 5nm, better not more than 3nm or 2nm,
• first amorphous sub-layer SnZnO preferably at least 20 nm or TiO 2 / barrier layer Si (Zr) N or SiO 2 preferably at least 10 nm / first contact layer AZO or (A) GZO / additional crystalline add layer AZO or (A) GZO / amorphous intermediate layer / second AZO contact layer or (A) GZO / Ag / onblocker / overcoat preferably ITO, MoO 3 , WO 3 , V 2 O 5 or AZO or ZnSnO (crystalline), possibly surmounted by a layer (TiN ...) of at most 5nm, better not more than 3nm or 2nm,
• first sub-layer Nb 2 0 5 preferably at least 20 nm / preferably barrier layer Si (Zr) N or SiO 2 / first contact layer AZO or (A) GZO / Agi additional crystalline layer AZO or (A) GZO / amorphous intermediate layer / second AZO contact layer or (A) GZO / Ag / onblocker / overcoat, preferably ITO, MoO 3 , WO 3 V 2 0 5 or AZO or ZnSnO (crystalline), optionally topped with a layer ( TiN ...) of at most 5nm, better at most 3nm or 2nm,
• first sub-layer Si Zr N / (amorphous layer SnZnO) / first contact layer AZO or (A) GZO / Agi additional crystalline layer AZO or (A) GZO / amorphous intermediate layer / second contact layer AZO or ( A) GZO / Ag / onblocker / overcoat preferably ITO, Mo0 3 , W0 3 V 2 0 5 or AZO or ZnSnO (crystalline), possibly topped with a layer (TiN ...) of at most 5nm, better d at most 3nm or 2nm,
• first amorphous sub-layer SnZnO / barrier layer Si Zr N or SiO 2 / first contact layer AZO or (A) GZO / Ag / additional crystalline layer AZO or (A) GZO / intermediate layer SnZnO amorphous / second layer of AZO contact or (A) GZO / Ag / onblock preferably Ti / overlayer preferably ITO preferably in the last layer,
• first sub-layer Nb 2 O 5 (/ Si (Zr) N or SiO 2 barrier layer) / first AZO contact layer or (A) GZO / Agi additional crystalline layer
• the contact layers and the additional layer are all AZO or all GZO and the barrier layer is Si (Zr) N or even silica and contains aluminum, the barrier layer being less than 15nm and even preferably less than 10 nm.
• each onblocker preferably titanium or even NiCr
• each onblocker can be at least partially oxidized.
• GZO is found to be more chemically inert than when one chooses for the additional layer (and the second contact layer) a layer of GZO to choose to maintain the thin intermediate layer as a reinforcement or not to insert it .
• the stack comprises only two silver layers.
• the stack comprising for example one or more other layers of silver, between the second layer of silver and another layer of silver and / or between each other silver layer, is added in this order directly on the layer of silver.
• silver medium another additional layer based on ZnO, preferably doped, preferably with a thickness greater than or equal to 40 nm, a possible other intermediate amorphous layer based on SnZnO or based on indium oxide and zinc or based on indium oxide, zinc and tin less than 15nm thick, another crystalline contact layer based on ZnO preferably less than 10nm thick.
• the total thickness of material containing (preferably predominantly, ie with a percentage by weight of indium greater than or equal to 50%) of the indium of this electrode is less than or equal to 80nm, or even less than or equal to 60nm.
• ITO, IZO may be mentioned as a layer (s) whose thicknesses it is preferable to limit.
• the electrode is in particular preferably free of layer (s) comprising indium, at least with a percentage by weight of indium greater than or equal to 50% by total weight of metal.
• the present invention further relates to an organic light-emitting diode (OLED) device comprising at least one lower electrode according to the present invention as described above.
• This electrode preferably plays the role of anode.
• the OLED then includes:
• the conductive support as defined above for an OLED device comprising at least one (full) electrode zone of size greater than or equal to 1 ⁇ 1 cm 2 , or even 5 ⁇ 5 cm 2 , even 10 ⁇ 10 cm 2 and beyond.
• An electroluminescent system with the organic layer above the lower electrode as defined above, can be provided to emit a polychromatic radiation defined at 0 ° by coordinates (x1, y1) in the CIE XYZ colorimetric diagram. 1931, coordinates given for radiation to normal.
• the OLED device can be emitted from the bottom and possibly also from the top depending on whether the cathode is reflective or semi-reflective, or even transparent (especially TL comparable to the anode typically from 60% and preferably greater than or equal to at 80%).
• the cathode may be used for a thin metal layer known as "TCC" (transparent conductive coating for example in Ag, Al, Pd, Cu, Pd, Pt, In, Mo, Au and typically of thickness between 5 and 150nm depending on the transmission / light reflection desired.
• TCC transparent conductive coating for example in Ag, Al, Pd, Cu, Pd, Pt, In, Mo, Au and typically of thickness between 5 and 150nm depending on the transmission / light reflection desired.
• a silver layer is transparent below 15 nm, opaque from 40 nm.
• 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 TiO 2 at least partially crystallized anatase form), or an anti-reflection stack of the type, for example Si 3 N 4 SiO 2 Si 3 N 4 SiO 2, or a UV filter such as, for example, a titanium oxide layer (TiO 2 ).
• It may also be one or a plurality of phosphor layers, a mirror layer, at least one scattering zone of 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) an illuminating, decorative, architectural system, etc.), a signaling 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 polychromatic light, especially for uniform illumination, or to produce different light areas of the same intensity or distinct intensity.
• 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 the facades of buildings.
• the OLED device in particular transparent by part (s) or entirely, can be:
• an external luminous glazing such as an external luminous glazing, an internal light partition or a part (part of) luminous glass door in particular sliding,
• a transport vehicle such as a bright roof, a (part of) side light window, an internal light partition of a land, water or air vehicle (car, truck train, airplane, boat, etc.) ,
• - 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 front, an illuminating slab, a ceiling lamp, a refrigerator lighting shelf, an aquarium wall.
• the cathode can be reflective. 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 split into two major families depending on the organic material used.
• SM-OLED Small Molecule Organic Light Emitting Diodes
• an SM-OLED consists of a stack of hole injection layers or "HIL” for "Hole Injection Layer” in English, hole transport layer or “HTL” for "Hole Transporting” Layer "in English, emissive layer, electron transport layer or” ETL “for” Electron Transporting Layer "in English.
• HIL hole injection layers
• HTL hole transport layer
• ETL Electron Transporting Layer
• organic electroluminescent stacks are for example described in the document entitled "Four wavelength white organic light emitting diodes using 4, 4'-bis [carbazoyl (9)] - stilbene as a deep blue emissive layer" of CH. Jeong et al., Published in Organics Electronics 8 (2007) pages 683-689.
• organic electroluminescent layers are polymers, it is called PLED ("Polymer Light Emitting Diodes" in English).
• the OLED organic layer or layers are generally index from 1, 8 or even higher (1, 9 even more).
• the OLED device may comprise a more or less thick OLED system for example between 50 and 350 nm.
• the electrode is suitable for tandem OLEDs, for example described in the publication entitled “Stacked white organic light-emitting devices based on a combination of fluorescent and phosphorent emitter” by H Kanno et al, applied phys lett 89 023503 (2006)
• OLED devices comprising a heavily doped "HTL” (Hole Transport Layer) layer as described in US7274141 for which the high output work of the last layer of the overlay is immaterial.
• HTL Hole Transport Layer
• the present invention further relates to a method of manufacturing the electrode of the conductive support according to the invention and even an OLED device incorporating it. This process naturally includes the deposition of the successive layers constituting the electrode described above.
• the deposition of all these layers is preferably done under vacuum, even more preferably by physical vapor deposition and better by cathodic sputtering (magnetron).
• the additional layer deposited on the first silver layer is doped zinc oxide, preferably aluminum and / or gallium, and is produced by cathodic sputtering (magnetron) from a doped zinc oxide ceramic target, preferably aluminum, and or gallium with, during the deposition, a rate (if any) of oxygen greater than or equal to 0% and less than 10% and better still less than or equal to 5% and a noble gas content (s) (preferably argon) at least 90% better by at least 95%.
• s noble gas content
• the second contact layer when the second contact layer is (directly) on the intermediate layer, the second contact layer is made of doped zinc oxide, preferably aluminum and / or gallium, and is produced by magnetron sputtering from a target zinc oxide ceramic doped preferably aluminum and / or gallium with during deposition an oxygen level greater than or equal to 0% and less than 10% and better still less than or equal to 5% and a noble gas ratio (s) ) (argon preferably) at least 90% better by at least 95%,
• the first contact layer is made by sputtering from a ceramic target, preferably doped zinc oxide preferably aluminum and / or gallium, with during the deposition a rate (if any) of oxygen lower than 10% and preferably less than or equal to 5% and a noble gas content (s) of at least 90% and preferably at least 95%.
• the second contact layer (and the first contact layer) and the additional layer are made by magnetron sputtering from the same doped zinc oxide target preferably aluminum and / or gallium with during the deposition an oxygen content of less than 10% and better still less than or equal to 5% and a noble gas content (argon preferably) of at least 90% better of at least 95%,
• the ceramic target and this low level of oxygen (possibly present) are chosen during the deposition of the additional layer in order to preserve as much as possible the first silver layer of oxygen, during the deposition of the additional layer.
• a ceramic target and a low oxygen level are also preferred for the first and the second contact layer to prevent a possible excess of oxygen which can diffuse into the silver layers (preferably directly on the contact layers) when annealing and thus to avoid possible degradation of optical and electrical properties and even to make possible the improvement of electrical properties by a better crystallinity of silver.
• each oxide layer is produced by cathodic sputtering (magnetron) from a ceramic target with during deposition a rate (if any) of limited oxygen, for example greater than or equal to 0% and less than 10% and better still less than 5% and a noble gas content (argon preferably) of at least 90% better of at least 95%.
• the overlay comprises or consists of a layer of ITO produced by cathodic sputtering (magnetron) from a ceramic target of tin and indium oxide with a (possible) rate of oxygen less than 10% and better still less than 5%.
• the process for producing the OLED according to the invention also comprises a step of heating the transparent electrode at a temperature greater than 180 ° C., preferably greater than 200 ° C., better still greater than or equal to 230 ° C., in particular from 250 ° C. to 400 ° C. or even up to 450 ° C., and ideally from 250 ° to 350 ° C., for a duration of preferably between 5 minutes and 120 minutes, in particular between 15 and 90 minutes.
• the electrode of the present invention knows:
• the invention advantageously proposes an electrode capable of (x) annealing (s) (to optimize its properties) or having undergone (at least) annealing.
• an annealing of 300 ° C is carried out for one hour and the optical and electrical properties are measured as above.
• the substrate may be flat or curved, and further rigid, flexible or semi-flexible.
• This substrate may be large, 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 (possibly divided into several zones called electrode surfaces) occupying substantially the surface area (near structuring areas and / or near edge areas)
• the substrate is substantially transparent. It may have a light transmission T L greater than or equal to 70%, preferably greater than or equal to 80% or even greater than or equal to 90%.
• the substrate may be mineral or plastic.
• the substrate may be, in particular, a layer based on polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate, polyurethane, polymethyl methacrylate, polyamide, polyimide, fluorinated polymer such as ethylene tetrafluoroethylene (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), ethylene chlorotrifluoroethylene (ECTFE), fluorinated ethylene-propylene copolymers (FEP).
• PET polyethylene terephthalate
• PEN polyethylene naphthalate
• PCTFE polychlorotrifluoroethylene
• ECTFE ethylene chlorotrifluoroethylene
• FEP fluorinated ethylene-propylene copolymers
• the substrate may be a lamination interlayer providing a connection with a rigid or flexible element.
• This polymeric lamination interlayer can be, in particular, a layer based on polybutyral vinyl (PVB), ethylene vinyl acetate (EVA), polyethylene (PE), polyvinyl chloride (PVC), thermoplastic urethane, polyurethane PU, ionomer, polyolefin-based adhesive, thermoplastic silicone or multi-component or multi-component resin, thermally crosslinkable (epoxy, PU) or ultraviolet (epoxy, acrylic resin).
• PVB polybutyral vinyl
• EVA ethylene vinyl acetate
• PE polyethylene
• PVC polyvinyl chloride
• thermoplastic urethane polyurethane PU
• ionomer polyolefin-based adhesive
• thermoplastic silicone or multi-component or multi-component resin thermally crosslinkable (epoxy, PU) or ultraviolet (epoxy, acrylic resin).
• the substrate may preferably be made of mineral glass, of silicate glass, in particular of soda-lime or silicosodium-calcium glass, a clear glass, extraclear or a float glass. It can be a high index glass (in particular index greater than 1, 6).
• 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.
• silicosodocalcic glasses with less than 0.05% Fe III or Fe 2 O 3 are chosen, for example Saint-Gobain Glass Diamond, Pilkington Optiwhite glass or Schott B270 glass.
• Saint-Gobain Glass Diamond for example Saint-Gobain Glass Diamond, Pilkington Optiwhite glass or Schott B270 glass.
• the substrate according to the invention comprises, on a second main face, a functional coating chosen from: an antireflection multilayer, an anti-fog or anti-fouling layer, an ultraviolet filter, in particular a titanium oxide layer, a phosphor layer, a mirror layer, a scattering zone of light extraction.
• a functional coating chosen from: an antireflection multilayer, an anti-fog or anti-fouling layer, an ultraviolet filter, in particular a titanium oxide layer, a phosphor layer, a mirror layer, a scattering zone of light extraction.
• the OLED system can be adapted to emit (substantially) white light, as close as possible to the coordinates (0.33, 0.33) or coordinates (0.45, 0.41), especially at 0 °.
• mixture of compounds green red emission, blue
• stack on the face of the electrodes of three organic structures green red emission, blue
• two organic structures yellow and blue
• the OLED device may be adapted to output a (substantially) white light, as close as possible to coordinates (0.33, 0.33), or coordinates (0.45, 0.41), especially at 0 ° .
• FIG. 1 represents a conductive support according to the invention.
• FIGS. 2a and 2b show characteristic optical microscopy images respectively of the conductive support of the prior art and of the conductive support according to the invention after annealing for one hour at 300 ° C.
• FIG. 3 is a scanning electron micrograph (SEM) of observed dendrites of the prior art conductive support after an hour-long annealing at 300 ° C.
• a stack of thin layers forming the transparent electrode according to the state of the art is prepared by magnetron sputtering, on the one hand, on a mineral glass, thus taking up the stack of the example 5 above (example called ExO), and, secondly, on a silica-mineral glass of T L 92% of thickness 0.7 mm, a thin film stack forming a transparent electrode according to the invention (example called Ex1) which differs from the electrode (ExO) in that it comprises:
• Ex1 R carried out as a preliminary test by the Applicant and which does not form part of the invention or the prior art distinguished from Ex1 by the presence of titanium.
• Table 1 shows in comparison the chemical composition and the thickness of all the layers forming these three electrodes.
• Figure 1 schematically shows the stack Ex1.
• Si 3 N 4 contains aluminum.
• the conditions of magnetron sputtering deposition, layers for ExO have already been mentioned above.
• the magnetron sputtering deposition conditions for each of the Exl and Ex1 R layers are as follows: the layer of SiAl (Si 3 N 4 : Al) is deposited by reactive sputtering using an aluminum doped silicon metal target in an argon / nitrogen atmosphere,
• each layer of SnZnO is deposited by reactive sputtering using a metal target of zinc and tin in an argon / oxygen atmosphere,
• each AZO layer is deposited by sputtering with a ceramic target of zinc oxide and alumina in an argon / oxygen atmosphere, with a low oxygen content,
• each layer of silver is deposited using a silver target, in a pure argon atmosphere,
• the or each layer of Ti is deposited using a titanium target, in a pure argon atmosphere,
• the ITO overlay is deposited using a ceramic target of indium oxide and tin oxide in an argon atmosphere enriched with a small amount of oxygen, so as to render it not very absorbent, ⁇ preferably becoming stoichiometric in oxygen.
• the Ti overblocking layer may be partially oxidized after ITO deposition over it.
• a metal target of zinc and antimony-doped tin comprising, by total weight of the target, for example 65% of Sn, 34% of Zn and 1% of Sb, or comprising, by total weight of the target 50% Sn, 49% Zn and 1% Sb.
• the ExO, Ex1 and Ex1 R electrodes are heated for 1 hour at a temperature of 300 ° C (annealing). We measure before and after this annealing:
• the metal contact between the external electrical circuit and the anode is taken on the surface of the anode, i.e. the ITO overlay.
• the ITO overcoat is conductive and the charge carriers thus diffuse towards the second layer of Ag, and are conducted laterally through the second layer of Ag, to then be injected into the organic layers, under the effect of the potential difference between the anode and the cathode, the latter being deposited on top of the last organic layer.
• the current In order for the first layer of Ag to contribute to the electrical conductivity of the anode, the current must be able to pass between the two layers of Ag.
• the contribution of the first silver layer depends on the ratio between the vertical resistance, R V ert, between the two layers of Ag and the lateral resistance, R La t, between the center of the OLED and the edge of the OLED, where the carriers are injected at the anode from the external circuit.
• Rvert is proportional to the thickness and the resistivity of the layer structure between the two layers of Ag, while R t depends, inter alia, the lateral distance, L t
• the carriers will be transported primarily through the top Ag layer in contact with the overcoat layer conductive ITO.
• the effective RD of the anode then corresponds only to that generated by the second layer of Ag.
• L increases, R
• R increases, R
• R increases, while Rvert remains constant. From a certain lateral distance, the lateral resistance becomes comparable to the vertical resistance, and the carriers are transported through the two layers of Ag.
• the effective RD of the anode then corresponds to that generated by the two Ag layers.
• the vertical resistance must therefore be as low as possible in order both to increase the size of the OLED for a given luminance uniformity and to reduce the energy consumption of the OLED, that is to say to increase its efficiency. luminous (Im / W).
• the R & D measured by the non-contact method is of the electromagnetic type, is here called RD E i m , using the Nagy measuring equipment.
• the RD measured in a conventional manner by the 4-point method is here called RD 4p , using the Napson measuring equipment.
• a measured RD substantially equal by 4-point techniques and without contact indicates that R Ve rt and R La t are comparable.
• the distance involved in the 4-point measurement is 3 mm.
• Table 3 shows the results of these R & D measurements, before and after annealing, for the Ex1 electrode, the Ex1 R electrode and the comparative ExO electrode, as well as their optical properties.
• the optical performance of ExO and Ex1, Ex1 R are comparable in contrast to electrical performance.
• the Ra 4p measured by the 4-point technique corresponds to approximately twice the value given by the measurement Rn e i m (2.8 ⁇ / ⁇ ).
• the thick interlayer of SnZnO before annealing, induces a high vertical resistance between the two layers of Ag, so that under the 4-point measuring conditions, the first layer of Ag does not contribute to the conductivity of the anode.
• the Ra 4p measured by the 4-tip technique is substantially equal to the value given by the non-contact measurement due to the greater vertical conductivity of AZO compared to SnZnO, which shows that the resistance
• the vertical separation layer is negligible, given OLED manufacturing considerations and size.
• the invention thus also relates to an anode which is not intended to be annealed, especially at least 250 ° C., for example when, alternatively, the substrate is made of plastic material because the anode according to the invention proves to be better than the prior art even without annealing. It is found that the annealing results in a degradation of the properties of the electrode of the comparative prior art ExO, that is to say:
• the electrode Ex1 according to the invention has these same improved properties (increase of T L and decrease of Abs, the resistance per square) in particular by improving the crystallinity of the silver layers.
• the absorption is thus lowered from 9.5 to 7.4% after annealing.
• the well-known roughness parameters R q and R max are measured by atomic force microscopy AFM on a measuring surface 5 * 5 * ⁇ " ⁇ 2 , and the measurements are collated in Table 4 below.
• the disadvantage of the anode Ex1 R with respect to the anode Ex1 is the degradation of the roughness R q which increases from 0.7 to 1.7 nm and R max which increases from 7 to 12 nm. after annealing. This increase in roughness is explained by the crystalline nature of the AZO layer, whereas the SnZnO is amorphous and less rough.
• the roughness R Q is greatly reduced, from 1.7 to 0.7 nm.
• the reason for this improvement is not yet clarified. Possible reasons would be an etching effect of the surface of the silver layer by the oxygen-containing plasma during the deposition of the additional layer of AZO, and / or a modified growth mode of the additional layer of AZO when deposited directly on Ag.
• the absence of the first overblock induces, in return, a degradation of the RD of 0.1 - 0.2 ⁇ / D, but which remains minor, and therefore acceptable under the OLED specifications.
• FIGS. 2a and 2b show optical microscopy images characteristic respectively of electrode Ex1 (according to the invention) and electrode ExO (according to the state of the art) after annealing at 300 ° C. for 1 hour.
• Figure 3 is a scanning electron microscope (SEM) picture of dendrites observed for the comparative ExO electrode.
• the use of the thin Si 3 N 4 : Al layer as a barrier layer between the first Ag layer and the first SnZnO layer prevents the formation of dendrites.
• the organic layers HTL / EBL (electron blocking layer) / EL / HBL (hole blocking layer) / ETL) are then deposited by evaporation under vacuum so as to produce an OLED which emits a white light.
• a metal cathode made of silver and / or aluminum is deposited by vacuum evaporation directly on the stack of organic layers. Variations are possible while remaining within the scope of the invention, that is to say with a separating layer providing the lowest possible vertical resistance and low roughness.
• ExV electrode was made by replacing in Ex1 the first sub layer of SnZnO with a TiO 2 layer.
• the TiO 2 layer is deposited by reactive sputtering using a titanium oxide ceramic target in an argon atmosphere with the addition of oxygen.
• Table 5 The conditions are summarized in Table 5 below:
• the electrode Ex1 'according to the invention after annealing at 300 ° C for 1 hour its improved properties (increase of T L and decrease in absorption, resistance per square). Ex1 'maintains a sufficiently low vertical resistance before and especially after annealing. Furthermore, it may be desired to use other sub-layers such as the niobium oxide layer and replace in Ex1 the first sub-layer of SnZnO with a layer of niobium oxide.
• the Si0 2 layer is an alternative barrier layer.
• the SiO 2 layer with aluminum is deposited by reactive sputtering using an aluminum doped silicon metal target in an argon / oxygen atmosphere. The conditions are summarized in the following Table 6: Index of
• SiAlO Si AI at 92: 8% in 2 10 "a mbar 0 2 / (Ar + 0 2 ) at 74% 1, 47 weight
• the aluminum doped silicon nitride barrier layer may alternatively be replaced by a silicon nitride and SiZrN: Al zirconium layer made from a "metallic" target in the total weight percentages of the following target: Si 76% weight, Zr 17% by weight, and Al 7% by weight under a reactive atmosphere.
• the AZO of the first contact layer and / or the second contact layer and / or the additional layer - and in particular ⁇ of a separating monolayer - can be replaced (preferably for all these layers) by the GZO produced at from a ceramic target, for example with a 98% by weight of Zn oxide and 2% by weight of Ga-oxide.
• magnetron sputtering is deposited on a silicosodocalcic mineral glass (such as SGGF glass, thickness mm), two other thin film stacks of the transparent electrodes according to the invention (examples called Ex2 and Ex3) which are distinguished from the electrode Ex1 by their sublayers.
• the first sub-layer of SiAl (Si 3 N 4 : Al) is deposited by reactive sputtering using an aluminum-doped silicon metal target, in an argon / nitrogen atmosphere, as in the Ex1 example.
• Thin layer of SnZnO in Ex 3 is deposited by reactive sputtering using a metal target of zinc and tin in an argon / oxygen atmosphere as in Example Ex1.
• ITO 50nm ITO 50nm
• the electrodes Ex2 and Ex3 are heated for 1 hour at a temperature of 300 ° C (annealing). We measure after this annealing:
• Table 8 shows the results of these measurements and R Q, after annealing for Ex2 and Ex3 electrodes according to the invention.
• the electrodes Ex2 and Ex3 according to the invention have their improved properties after annealing (increase of T L and decrease of the absorption, the resistance per square).
• the large thickness of the AZO layer used for the separating monolayer in the preceding examples according to the invention can make each stack too fragile with regard to certain chemical procedures, in particular involving those involving acid treatments, or long exposure times. at high humidity levels.
• the intermediate layer preferably SnZnO may remain essential for the better resistance to chemical treatments OLED which are cleaning including the following procedure:
• the detergent is TFDO W sold by Franklab SA. It is organic, non-foaming, with ionic and nonionic surfactants, chelating agents and stabilizers.
• the pH is about 6.8 to 3% dilution.
• New examples were made by inserting into the separating layer a thin intermediate layer preferably chosen from SnZnO.
• a thin intermediate layer preferably chosen from SnZnO.
• ITO 50nm ITO 50nm
• the electrodes Ex2bis and Ex3bis are heated for 1 hour at a temperature of 300 ° C (annealing). We measure after this annealing:
• Table 10 shows the results of these measurements and R Q, after annealing for Ex2bis electrodes and Ex3bis according to the invention.
• Ex2bis and Ex3bis electrodes according to the invention have their improved properties after annealing (increase of T L and decrease in absorption, resistance per square).
• annealing thanks to the separating layer, it is particularly noted that after annealing, the RD measured by the contact and contactless methods are equivalent for each of Ex2bis and Ex3bis electrodes, which shows that the vertical resistance remains negligible even with the thin intermediate layer, given OLED manufacturing considerations, and their size.
• the upper face (the farthest from the substrate) of the thin intermediate layer is closer to the second layer of silver than is the lower face (closest to the substrate) of the first silver layer.
• the AZO contact layers are replaced by ZnSnO with less than 5% by weight of Sn
• another embodiment consists of inserting one or more other SnZnO layers within the additional layer of AZO, thus N other identical SnZnO layers ( preferably N ⁇ 4), each layer / ' of
• SnZnO having a thickness t, and being located at the distance d, from the second layer of Ag and for example regularly distributed and / or of the same thickness (less than or equal to 8 nm, for example 5 nm in particular).
• the additional layer of thickness e 2 is formed by two layers called disjoint AZO buffer, each of thickness e 2 i and e 2 2 of 42 nm (with e 2 i + e 22 equal to e 2 and equal to 84nm here).
• the replacement of the thick SnZnO layers between the Ag layers with AZO layers was also tested for three-layer Ag stacks, so the separating layer between the middle silver layer and the last one was repeated. layer of money.
• the AZO layers are therefore directly on the first layer of silver and on the silver layer of the medium. Similar to the bi-Ag stacks, the dendrites are removed after annealing, the RDs measured by the 4-point and contactless methods are substantially equal, of very low roughness and the optical and electrical properties are greatly improved after annealing.
• the exemplified electrodes therefore meet the following specifications:

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