JP4468546B2 - Transparent electrode - Google Patents

Description

【００３９】
（表１）の結果から、すべての実施例において、本発明によって、発光初期輝度及び発光輝度半減時間が大幅に向上していることが分かる。
【００４０】
【発明の効果】
本発明は、透明導電性薄膜積層層の厚みを制限すること、ガスバリヤー層の形成により酸素ガス透過性及び水蒸気透過性を制限すること、さらには最表面層を透明導電性高屈折率薄膜層に制限することにより、発光輝度及び発光耐久性に優れる有機エレクトロルミネッセンス素子を製造することができる透明電極を提供することを可能にした。
【図面の簡単な説明】
【図１】透明電極の一例を示す断面図
【図２】透明電極の一例を示す断面図
【図３】透明電極の一例を示す断面図
【符号の説明】
１０：透明高分子成形基体（Ａ）
２０：透明導電性高屈折率薄膜層（ａ）
３０：銀または銀の合金薄膜層（ｂ）
４０：透明高屈折率薄膜層（ｃ）
５０：ガスバリヤー層（ｄ）[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a transparent electrode that makes it possible to provide a light emitting device having excellent light emission luminance and light emission durability.
[0002]
[Prior art]
The transparent electrode has conductivity despite being transparent, and a typical example thereof is one in which a thin film made of an oxide of indium and tin (ITO) is formed on a glass substrate. It is done. The main application is the surface electrode of the visual recognition part of the display panel, which is currently widely used for liquid crystal displays (LCD), electroluminescence (EL) displays, plasma display panels (PDP) and the like. Recently, an organic electroluminescence (OEL) display and a field emission display (FED) are attracting attention as one of the next generation displays.
[0003]
Recently, there is a great need for an increase in the size and size of a display panel. In order to realize this, it is necessary to reduce the power consumption of the display element. For this purpose, it is effective to develop a transparent electrode having a low resistance value while maintaining the visible light transmittance. In particular, recently developed organic electroluminescence elements are self-luminous type and are mainly developed for small portable terminals, so there is a great expectation for reducing the resistance of transparent electrodes.
In addition, with regard to plasma display panels (PDPs) that are now spreading to the market and field emission displays (FEDs) that are being developed as next-generation displays, the development of low-resistance transparent electrodes because of their high power consumption structure. Expectation is great.
[0004]
As a means for realizing a low-resistance transparent electrode, it is effective to use a transparent conductive thin film laminate. The transparent conductive thin film laminate is obtained by sandwiching a metal thin film excellent in conductivity between transparent high refractive index thin films. The conductivity of the transparent conductive thin film laminate depends mainly on the conductivity of the metal thin film layer, and high conductivity that cannot be achieved with conventional transparent conductive thin films can be obtained. This transparent conductive thin film laminate is very useful because it can be designed to have optimum optical and electrical characteristics depending on the application by selecting the material and film thickness of each thin film layer.
[0005]
When an organic electroluminescence device is fabricated using a transparent electrode, the ease of accepting electrons from the portion in contact with the transparent electrode (transparent electrode contact surface) is the magnitude of the contact resistance between the transparent electrode outermost surface and the transparent electrode contact surface. It depends on the surface resistance of the transparent electrode outermost surface.
Further, the light emission lifetime of the organic electroluminescence element depends on the gas barrier property of the transparent electrode.
However, the transparent electrode using the conventional transparent conductive thin film laminate has a remarkably high surface resistance value compared to the theoretical value calculated from the thickness of the metal thin film layer. Sufficient emission brightness could not be obtained. Further, since the gas barrier property with respect to the atmosphere is not sufficient, the light emission life cannot be maintained sufficiently.
[0006]
[Problems to be solved by the invention]
An object of the present invention is to provide a transparent electrode that solves the above-described problems and makes it possible to produce an organic electroluminescence device that maintains sufficient light emission luminance and light emission lifetime.
[0007]
[Means for Solving the Problems]
  As a result of intensive studies to solve the above problems, the present inventors have found that a transparent electrode having a specific performance exhibits excellent performance, and have completed the present invention. That is, the present invention provides (1) a transparent conductive high refractive index thin film layer (a), a metal thin film layer (b) made of silver or a silver alloy, a transparent high refractive index thin film on a transparent polymer molded substrate (A). The layer (c) and the gas barrier layer (d) are laminated in a configuration of A / d / c / b / a or d / A / c / b / a or d / A / d / c / b / a. The total thickness of the films other than the laminated gas barrier layer (d) is 60 nm or more and 100 nm or less, and the specific resistance of the transparent conductive high refractive index thin film layer (a) is 1 × 10^-7Ω · cm or more, 1 × 10²Ω · cm or less, and oxygen gas permeability of the transparent electrode is 0.001 cc / m²/ Day / atm or more, 1cc / m²/ Day / atm or less, and water vapor permeability is 0.001 g / m.²/ Day / atm or more, 1 g / m²/ Day / atm or lessThe transparent conductive high refractive index thin film layer (a) is made of an oxide of zinc and aluminum containing aluminum in a proportion of 1 wt% or more and 10 wt% or less.A transparent electrode, characterized by(2)The transparent high refractive index thin film layer (c) is made of an oxide of indium and tin or an oxide of zinc and aluminum.(1)Transparent electrode according to(3)The metal thin film layer (b) is made of an alloy of silver and gold or an alloy of silver, copper and palladium.(1) or (2)Transparent electrode according to(4)Gas barrier layer (d) is silicon oxide or silicon oxideAnd silicon nitrideIt consists of the compound of(1) to (3)The transparent electrode according to any one of(5) Said (1)-(4)The organic electroluminescent element using the transparent electrode in any one of these.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
  The transparent electrode of the present invention comprises a transparent conductive high refractive index thin film layer (a), a metal thin film layer (b) made of silver or a silver alloy, a transparent high refractive index thin film layer ( c) and a gas barrier layer (d) transparent laminated in a configuration of A / d / c / b / a or d / A / c / b / a or d / A / d / c / b / a The total film thickness of the films other than the gas barrier layer (d) that is an electrode is 60 nm or more and 100 nm or less, and the specific resistance of the transparent conductive high refractive index thin film layer (a) is 1 × 10^-7Ω · cm or more, 1 × 10^-1Ω · cm or less, and oxygen gas permeability of the transparent electrode is 0.001 cc / m²/ Day /atm or more1cc / m²/ Day / atm or less, and water vapor permeability is 0.001 g / m.²/ Day / atm or more, 1 g / m²/ Day / atm or lessThe transparent conductive high refractive index thin film layer (a) is made of an oxide of zinc and aluminum containing aluminum in a proportion of 1 wt% or more and 10 wt% or less.It is characterized by that. The transparent electrode of the present invention makes it possible to increase the light emission luminance and extend the light emission lifetime when an organic electroluminescence device is produced using the transparent electrode to emit light.
[0009]
The transparent electrode of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing an example of a transparent electrode in the present invention. (FIG. 1) is a transparent conductive high refractive index thin film layer (a) 20, a metal thin film layer (b) 30, a transparent high refractive index thin film layer (c) 40, on a transparent polymer molded substrate (A) 10. An example of a transparent electrode in which the gas barrier layer (d) 50 is a laminated structure A / d / c / b / a is shown. (FIG. 2) shows a transparent electrode having a laminated structure of d / A / c / b / a, and (FIG. 3) having a laminated structure of d / A / d / c / b / a. .
[0010]
The transparent polymer molded substrate used in the transparent electrode of the present invention is mainly used in the state of a film and a plate, has excellent transparency, and has sufficient mechanical strength depending on the application. Is preferred. Here, being excellent in transparency means that the visible light transmittance is 40% or more in the thickness in a used state.
Further, an antireflection layer or an antiglare layer may be formed on the surface opposite to the main surface of the transparent polymer molded substrate.
[0011]
As the film for the transparent polymer molded substrate, a polymer film is preferably used. Specifically, as the polymer, polyimide, polysulfone (PSF), polyether sulfone (PES), polyethylene terephthalate (PET), polymethylene methacrylate (PMMA), polycarbonate (PC), polyether ether ketone (PEEK) , Polypropylene (PP), triacetyl cellulose (TAC) and the like. Among these, polyethylene terephthalate (PET) and triacetyl cellulose (TAC) are particularly preferably used.
There is no particular limitation on the thickness of the transparent substrate film. Usually, it is about 20-500 micrometers.
[0012]
Examples of the plate-like transparent substrate include a transparent polymer molded body. The transparent polymer molded body is more suitably used for reasons such as being lighter and harder to break than glass. Examples of preferred materials include acrylic resins such as polymethyl methacrylate (PMMA), polycarbonate resins and the like, but are not limited to these resins. Among them, PMMA can be preferably used because of its high transparency and high mechanical strength in a wide wavelength region.
Further, the transparent polymer molded body is often provided with a hard coat layer for the reason of increasing the hardness or adhesion of the surface.
There is no particular limitation on the thickness of the plate-like transparent substrate, and it is sufficient that sufficient mechanical strength and rigidity to maintain flatness without bending are obtained. Usually, it is about 0.5 to 10 mm.
[0013]
The transparent electrode according to the present invention has a transparent conductive high refractive index thin film layer (a), a transparent high refractive index thin film layer (b), a metal thin film layer (c), and a gas barrier layer (d) that transmit sufficient visible light. It is obtained by laminating on a transparent substrate with a combination of film thicknesses that can obtain a rate and a surface resistance value.
The visible light transmittance of the transparent conductive thin film laminate layer is preferably 40% or more and 99% or less, more preferably 50% or more and 99% or less, and still more preferably 60% or more and 99% or less.
Further, the preferable surface resistance value is 0.2Ω / □ or more and 100Ω / □ or less, preferably 0.2Ω / □ or more, 10Ω / □ or less, more preferably 0.2Ω / □ or more and 3Ω / □ or less. Even more preferably, it is 0.2Ω / □ or more and 0.5Ω / □ or less.
[0014]
It is preferable that the material used for the transparent conductive high refractive index thin film layer (a) is as excellent in transparency and conductivity as possible. Here, excellent transparency means that when a thin film having a thickness of about 100 nm is formed, the visible light transmittance of the thin film is 60% or more, and excellent conductivity means that the thickness is about 100 nm. When the thin film is formed, the sheet resistance value of the thin film is 1 × 10⁷Indicates that it is less than Ω / □. The high refractive index material is a material having a refractive index with respect to light of 550 nm of 1.4 or more. These may be mixed with impurities depending on the application. Materials that can be suitably used for transparent high refractive index thin film layersIllustrative examples include zinc and aluminum oxide (AZO).
[0015]
The thickness of the transparent conductive high refractive index thin film layer is determined in consideration of the transparency and electric conductivity of the entire transparent electrode. Usually, it is about 10-60 nm.
The transparent conductive high refractive index thin film layer of the present invention has a specific resistance of 1 × 10^-7Ω · cm or more, 1 × 10²The film forming condition is determined by forming a transparent conductive high refractive index thin film layer on a glass substrate in advance and obtaining a specific resistance value from the film thickness and surface resistance. It is formed by laminating on a metal thin film layer.
The specific resistance of the transparent conductive high refractive index thin film layer in the present invention can be easily estimated by examining the surface resistance of the transparent electrode. The specific resistance value of the thin film layer is 1 × 10²When it is larger than Ω · cm, the surface resistance of the transparent electrode is 1 × 10⁶It becomes Ω · cm or more, and the surface becomes insulative.
[0016]
As a material of the metal thin film layer (b) used in the present invention, a material having as good electrical conductivity as possible is preferable, and silver or a silver alloy is used. Silver has a specific resistance of 1.59 × 10^-6Since it is Ω · cm and has the highest electrical conductivity among all materials, and the visible light transmittance of the thin film is excellent, it is most preferably used.
However, silver lacks stability when formed into a thin film and has a problem that it is susceptible to sulfidation and chlorination. Therefore, in order to increase the stability, instead of silver, an alloy of silver and gold, an alloy of silver and copper, an alloy of silver and palladium, an alloy of silver, copper and palladium, an alloy of silver and platinum, etc. are used. Also good.
The thickness of the metal thin film layer is determined in consideration of the transparency and electrical conductivity of the entire transparent electrode. Usually, it is about 0.5 to 30 nm.
[0017]
The material used for the transparent high-refractive-index thin film layer (c) is preferably as excellent as possible in transparency. Here, excellent transparency means that when a thin film having a thickness of about 100 nm is formed, the visible light transmittance of the thin film is 60% or more. The high refractive index material is a material having a refractive index with respect to light of 550 nm of 1.4 or more. These may be mixed with impurities depending on the application.
[0018]
Examples of materials that can be suitably used for the transparent high refractive index thin film layer include oxides of indium and tin (ITO), oxides of cadmium and tin (CTO), and aluminum oxide (Al₂O_Three), Zinc oxide (ZnO), oxide of zinc and aluminum (AZO), magnesium oxide (MgO), thorium oxide (ThO)₂), Tin oxide (SnO)₂), Lanthanum oxide (La₂O_Three), Silicon oxide (SiO₂), Indium oxide (In₂O_Three), Niobium oxide (Nb)₂O_Three), Antimony oxide (Sb)₂O_Three), Zirconium oxide (ZrO)₂), Cerium oxide (CeO)₂), Titanium oxide (TiO₂), Bismuth oxide (BiO)₂) Etc.
A transparent high refractive index sulfide may be used. Specifically, zinc sulfide (ZnS), cadmium sulfide (CdS), antimony sulfide (Sb)₂S_Three) Etc.
[0019]
Transparent high refractive index thin film materials include, among others, ITO, TiO₂ZnO is particularly preferred. ITO and ZnO have electrical conductivity and have a high refractive index of about 2.0 in the visible region, and hardly absorb in the visible region. TiO₂Is an insulator and has a slight absorption in the visible region, but has a high refractive index of about 2.3 for visible light.
The thickness of the transparent high refractive index thin film layer is determined in consideration of the transparency and electrical conductivity of the entire transparent electrode. Usually, it is about 10-60 nm.
[0020]
In the present invention, the total film thickness of the transparent conductive thin film layer composed of a transparent conductive high refractive index thin film layer, a metal thin film layer made of silver or a silver alloy, and a transparent high refractive index thin film layer is optical characteristics and electrical characteristics. Is taken into consideration, the film thickness of each layer is determined, and the total is obtained. If the total film thickness is too thick, there is room for the surface irregularities to become too large. In this case, the contact resistance value between the outermost surface of the transparent electrode and the transparent electrode contact surface increases, which is not preferable.
In the transparent electrode of the present invention, the film thickness of the transparent conductive thin film laminate layer is 60 nm or more and 100 nm or less.
[0021]
The gas barrier layer (d) in the present invention may be designed so that sufficient visible light transmittance and gas barrier properties can be obtained. The gas barrier performance required in the present invention is a gas barrier performance against oxygen and water vapor. The preferable visible light transmittance of the gas barrier layer is 60% or more and 99% or less.
In the transparent electrode of the present invention, the oxygen gas permeability is 0.001 cc / m.²/ Day / atm or more, 1cc / m²/ Day / atm or less, more preferably 0.001 cc / m²/ Day / atm or more, 0.5cc / m²/ Day / atm or less. Water vapor gas permeability is 0.001 g / m²/ Day / atm or more, 1 g / m²/ Day / atm or less, more preferably 0.001 g / m²/ Day / atm or more, 0.5 g / m²/ Day / atm or less.
[0022]
As a material used for forming the gas barrier layer, a silicon compound is preferably used. Specific examples include silicon oxide, silicon nitride, and a compound of silicon oxide and silicon nitride.
The composition of the gas barrier layer is not particularly limited as long as the gas barrier performance is obtained and the transparency is maintained. For example, silicon oxide can be generally described as SiOx, but the range of x is usually about 1.0 to 2.5.
There are no particular limitations on the formation position of the gas barrier layer as long as the gas barrier performance can be obtained and a stable thin film that can maintain transparency can be formed. Usually, it is formed on at least one surface of the transparent polymer molded substrate.
The thickness of the gas barrier layer is not particularly limited as long as the thickness is within a range that does not impair the transparency, and can maintain gas barrier properties and ensure adhesion with the transparent polymer molded substrate. . Specifically, 20 to 500 nm is preferable, and 20 to 100 nm is more preferable. If the thin film layer is too thin, it is difficult to obtain a uniform and continuous film. If the thin film layer is too thick, the adhesion to the substrate is reduced or the thin film layer is liable to break.
[0023]
In the transparent electrode of the present invention, a transparent conductive high refractive index thin film layer, a transparent high refractive index thin film layer, a metal thin film layer, and a gas barrier layer are conventionally known, such as vacuum deposition, ion plating, and sputtering. This method may be used.
For forming the transparent conductive high refractive index thin film layer, the transparent high refractive index thin film layer, and the gas barrier layer, an ion plating method or a reactive sputtering method is preferably used. In the ion plating method, vacuum deposition is performed by resistance heating a desired metal or sintered body in a reactive gas plasma or by heating with an electron beam. In the reactive sputtering method, a desired metal or sintered body is used as a target, an inert gas such as argon or neon is used as a sputtering gas, and a gas necessary for the reaction is added to perform sputtering. For example, when forming an ITO thin film, direct current magnetron sputtering is performed in an oxygen gas using an oxide of indium and tin as a sputtering target.
[0024]
A vacuum vapor deposition method or a sputtering method is suitably used for the metal thin film layer. In the vacuum vapor deposition method, a desired metal can be used as a vapor deposition source, and a metal thin film can be easily formed by heat vapor deposition by resistance heating, electron beam heating, or the like. When sputtering is used, a desired metal material is used as a target, an inert gas such as argon or neon is used as a sputtering gas, and a metal thin film is formed using DC sputtering or high-frequency sputtering. Can do. In order to increase the deposition rate, a direct current magnetron sputtering method or a high frequency magnetron sputtering method is often used.
[0025]
For the formation of the gas barrier layer, conventionally known means such as a wet method or a chemical vapor deposition method may be used in addition to the physical vapor deposition method such as the ion plating method and the reactive sputtering method.
Examples of the wet method include a sol-gel method and a method in which a solution in which polysilazane is melted is applied and heated in a water vapor atmosphere in the air to form a silicon oxide film. Polysilazane here means (SiN_xH_y) Perhydropolysilazane having a structure of (x = 1 to 3, y = 0 to 1), in which only hydrogen is bonded as a side chain to (—Si—N—) of the main chain. Since the polysilazane can be dissolved in a solvent such as benzene, toluene, xylene, ether, THF, methylene chloride, carbon tetrachloride and the like in an amount of 20% by weight or more, after dissolving the polysilazane in these solvents, Silicon oxide can be obtained by coating and heat treatment.
In general, in order to obtain inorganic silicon oxide, heat treatment at 450 ° C. or higher is necessary. By using an amine or a transition metal catalyst, the inorganic silicon oxide can be heated at a low temperature, for example, 80 to 150 ° C. Is obtained. The heat treatment time at this time is about 1 to 3 hours. The molecular weight of polysilazane used for coating is preferably 600 to 900.
[0026]
The chemical vapor deposition method is a method in which an organic silicon compound is used as a raw material and decomposed by inputting energy into the raw material to deposit inorganic silicon oxide. There are heat, light, high-frequency plasma, and the like as methods for inputting energy, and these may be selected as appropriate. In the chemical vapor deposition method, since the vapor of an organosilicon compound is used as a raw material, silicon oxide is formed regardless of the unevenness of the surface of the film molded body. Therefore, when the surface smoothness of the film molded body is not so high Furthermore, it has a high surface coverage and can be most preferably used as a gas barrier film forming method. Among these, the low-pressure plasma chemical vapor deposition method can be more preferably used because silicon oxide having excellent gas barrier properties can be formed without damaging the film molded body.
[0027]
The atomic composition of the surface of the thin film layer of the transparent conductive thin film laminate produced by the above method is Auger electron spectroscopy (AES), X-ray fluorescence (XRF), X-ray microanalysis (XMA), charged particles Excitation X-ray analysis (RBS), X-ray photoelectron spectroscopy (XPS), vacuum ultraviolet photoelectron spectroscopy (UPS), infrared absorption spectroscopy (IR), Raman spectroscopy, secondary ion mass spectrometry (SIMS), It can be measured by low energy ion scattering spectroscopy (ISS) or the like. The atomic composition and film thickness in the film can be examined by performing Auger electron spectroscopy (AES) or secondary ion mass spectrometry (SIMS) in the depth direction.
[0028]
The configuration of the transparent conductive thin film laminate and the state of each layer can be examined by optical cross-sectional measurement, scanning electron microscope (SEM) measurement, and transmission electron microscope measurement (TEM) of the cross section.
In order to evaluate the performance of the transparent electrode during light emission, a light-emitting element is actually produced using the transparent electrode, and the durability, visibility, and the like at that time are examined.
In order to evaluate the performance of the transparent electrode used for organic electroluminescence, an organic electroluminescence element is produced using the transparent electrode to be evaluated, and element evaluation is performed. A method for producing an organic electroluminescence element is obtained by laminating a hole transport layer, a light emitting layer, and a cathode on a transparent conductive thin film of a transparent electrode in a configuration of transparent electrode / hole transport layer / light emitting layer / cathode. .
[0029]
The material used for the hole transport layer is preferably used because, for example, a diamine-based organic compound is excellent in hole transport ability. In particular, N, N′-bis (3-methylphenyl) -N, N′-diphenylbenzidine (abbreviation TPD) is excellent in hole transport capability and widely used as a hole transport material.
Examples of the material used for the light-emitting layer include an aluminum quinolinol complex (8 hydroxyquinoline aluminum) (abbreviation, Alq3), 1,2,3,4,5-pentaphenyl-1,3-cyclopentadiene (abbreviation: PPCP), 2- (4′-biphenylyl) -5- (4′-t-butylphenyl) -1,3,4-oxadiazole (abbreviation PBD), NN′-bis [2 ′, 5′-di ( t-butyl) phenyl] -3,4,9,10-perylenedicarboximide (abbreviation BPPC) and the like.
[0030]
For the formation of these hole transport layers and light emitting layers, a conventionally known physical vapor deposition method such as vacuum deposition method or ionization deposition method, or a desired material is dispersed in an appropriate solvent and applied by a method such as spin coating. Then, a wet method for drying may be used.
The thickness of the hole transport layer and the light emitting layer is usually 30 to 200 nm, respectively.
The material used for the cathode is an alloy of magnesium and silver, an alloy of magnesium and aluminum, or the like. For the formation of these cathodes, a conventionally known physical film forming method such as a vacuum deposition method or a sputtering method may be used. The thickness of the cathode is usually about 5 to 500 nm.
In order to further improve the light emission efficiency, an appropriate electron transport layer may be inserted between the light emitting layer and the cathode.
[0031]
The light emission luminance can be evaluated by measuring the light emission luminance of the element using a luminance meter.
Further, the evaluation of the light emission durability can be performed, for example, by examining the time until the light emission luminance becomes half of the initial value.
[0032]
【Example】
EXAMPLES Next, although an Example demonstrates this invention concretely, this invention is not restrict | limited at all by this.
[0033]
Reference example
A polyethylene terephthalate film [manufactured by Teijin Ltd., product name: HSL, thickness: 188 μm] was prepared as the transparent polymer molded substrate (A). A silicon oxide thin film layer (d) [thickness 100 nm] was formed on one main surface of the film by using a high-frequency plasma sputtering method. In forming the silicon oxide thin film layer, silicon oxide was used as a target, and an argon / oxygen mixed gas (total pressure 266 mPa, oxygen partial pressure 16 mPa) was used as the sputtering gas. Next, a thin film layer (a) made of an oxide of indium and tin, a thin film layer (b) made of an alloy of silver, palladium and copper, and an oxide of indium and tin using a direct current magnetron sputtering method. The thin film layer (c) consisting of was laminated in the order of d / A / c [thickness 40 nm] / b [thickness 9 nm] / a [thickness 40 nm] to form a transparent conductive thin film laminate film. The thin film layer (a) of indium and tin isTransparent conductive high refractive index thin film layerThe alloy thin film layer of silver, palladium and copper constitutes a metal thin film layer, and the thin film layer (c) of indium and tin constitutes a transparent high refractive index thin film layer. For the formation of the thin film layer (a) made of an oxide of indium and tin, an indium oxide-tin oxide sintered body [In₂O₃: SnO₂= 90: 10 (weight ratio)], an argon / oxygen mixed gas (total pressure 266 mPa, oxygen partial pressure 8 mPa) was used as the sputtering gas. Further, for the formation of the alloy thin film layer (b) of silver, palladium and copper, an alloy of silver, palladium and copper [Ag: Pd: Cu = 99: 0.5: 0.5 (weight ratio)] is used as a target. Argon gas (total pressure 266 mPa) was used as the sputtering gas. For the formation of the thin film layer (c) made of an oxide of indium and tin, an indium oxide-tin oxide sintered body [In₂O₃: SnO₂= 90: 10 (weight ratio)], an argon / oxygen mixed gas (total pressure 266 mPa, oxygen partial pressure 26 mPa) was used as the sputtering gas. The specific resistance of the high refractive index thin film layer, the oxygen gas permeability of the transparent electrode, and the water vapor permeability are shown in Table 1. The specific resistance of the high refractive index thin film layer was determined by forming only a transparent conductive thin film on a glass substrate and measuring the film thickness and surface resistance, and each transmittance was measured according to ASTM 1434.
[0034]
Using the obtained transparent electrode, an organic electroluminescence element was produced, and a light emission test was performed.
First, N, N′-bis (3-methylphenyl) -N, N′-diphenylbenzidine (abbreviation: TPD) is used as a hole transport layer by vacuum heating vapor deposition on the transparent conductive thin film of the transparent electrode. A layer [50 nm] was formed.
Next, an 8-hydroxyquinoline aluminum (abbreviation: Alq3) layer [50 nm] was formed thereon as a light-emitting layer using a vacuum heating deposition method.
Further, a magnesium layer [2 nm] was formed as a cathode by vacuum heating vapor deposition.
A 10 V DC voltage was applied between the anode and the cathode of the organic electroluminescence device produced as described above to light it.
First, the luminance was measured using a luminance meter (LS-110 manufactured by Minolta) to examine the emission luminance. Next, the light emission luminance half time was examined. Here, the light emission luminance half time represents a time until the light emission luminance becomes 1/2 of the initial light emission luminance.
The evaluation results are shown in (Table 1).
[0035]
Comparative Example 1
Reference exampleIn addition, except that an argon / oxygen mixed gas (total pressure 266 mPa, oxygen partial pressure 26 mPa) was used as a sputtering gas when forming the thin film layer (a) made of an oxide of indium and tin,Reference exampleIt carried out like. The evaluation result of the obtained transparent electrode and organic electroluminescent element was shown in (Table 1).
[0036]
Example
Instead of a thin film layer (a) made of an oxide of indium and tin, a thin film layer (a) made of an oxide of zinc and aluminum is used as a target and an oxide sintered body of zinc and aluminum [ZnO: Al₂O₃= 98: 2 (weight ratio)], argon gas (total pressure 266 mPa) is used as a sputtering gas, and a thin film layer made of an oxide of zinc and aluminum is used instead of the thin film layer (c) made of an oxide of indium and tin. Using (c) as a target, an oxide sintered body of zinc and aluminum [ZnO: Al₂O₃= 98: 2 (weight ratio)], except that argon gas (total pressure 266 mPa) was used as the sputtering gas,Reference exampleIt carried out like. The evaluation result of the obtained transparent electrode and organic electroluminescent element was shown in (Table 1).
[0037]
Comparative Example 2
ExampleIn addition, except that an argon / oxygen mixed gas (total pressure 266 mPa, oxygen partial pressure 5 mPa) was used as the sputtering gas when forming the thin film layer (a) made of an oxide of zinc and aluminum,ExampleIt carried out like. The evaluation result of the obtained transparent electrode and organic electroluminescent element was shown in (Table 1).
[0038]
[Table 1]

[0039]
From the results of (Table 1), it can be seen that in all Examples, the initial luminance of light emission and the half time of light emission luminance are greatly improved by the present invention.
[0040]
【The invention's effect】
The present invention restricts the thickness of the transparent conductive thin film laminate layer, restricts oxygen gas permeability and water vapor permeability by forming a gas barrier layer, and further, the outermost surface layer is a transparent conductive high refractive index thin film layer. By limiting to the above, it is possible to provide a transparent electrode capable of producing an organic electroluminescence device excellent in light emission luminance and light emission durability.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of a transparent electrode
FIG. 2 is a cross-sectional view showing an example of a transparent electrode
FIG. 3 is a cross-sectional view showing an example of a transparent electrode
[Explanation of symbols]
10: Transparent polymer molded substrate (A)
20: Transparent conductive high refractive index thin film layer (a)
30: Silver or silver alloy thin film layer (b)
40: Transparent high refractive index thin film layer (c)
50: Gas barrier layer (d)

Claims (5)

On the transparent polymer molded substrate (A), a transparent conductive high refractive index thin film layer (a), a metal thin film layer (b) made of silver or a silver alloy, a transparent high refractive index thin film layer (c), a gas barrier layer ( d) are laminated in a configuration of A / d / c / b / a or d / A / c / b / a or d / A / d / c / b / a, and a laminated gas barrier layer The total film thickness of films other than (d) is 60 nm or more and 100 nm or less, and the specific resistance of the transparent conductive high refractive index thin film layer (a) is 1 × 10 ⁻⁷ Ω · cm or more, 1 × 10 ² Ω · cm or less, and an oxygen gas permeability of the transparent electrode is 0.001cc ^/ m 2 ^/ day ^/ atm or ^{higher, 1cc / m 2 / day /} atm or less, the water vapor permeability of 0.001 g ^{/ m} 2 / It is not less than day / atm and not more than 1 g / m ² / day / atm ,
The transparent electrode, wherein the transparent conductive high refractive index thin film layer (a) is made of an oxide of zinc and aluminum containing aluminum in a proportion of 1 wt% to 10 wt% . 2. The transparent electrode according to claim 1, wherein the transparent high refractive index thin film layer (c) is made of an oxide of indium and tin or an oxide of zinc and aluminum. The transparent electrode according to claim 1 or 2 , wherein the metal thin film layer (b) is made of an alloy of silver and gold, or an alloy of silver, copper and palladium. The transparent electrode according to any one of claims 1 to 3 , wherein the gas barrier layer (d) is made of silicon oxide or a compound of silicon oxide and silicon nitride . The organic electroluminescent element using the transparent electrode in any one of Claims 1-4 .

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