JP2002015623A - Transparent electrode - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparent electrode which is superior in a uniformity of light emission in a surface and not poor in luminosity in the region of 600 to 700 nm when a light emitting element is prepared. SOLUTION: Performances of the transparent electrode are limited so that surface resistance values are 7 Ω/(square) to 12 Ω/(square), and transmissivities are 70% to 99% or less in the wave length region of 600 to 700 nm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent electrode capable of providing a light emitting device having excellent surface emission uniformity and red light emission luminance, and an organic electroluminescence device using the same.

[0002]

2. Description of the Related Art A transparent electrode has conductivity in spite of being transparent. As a typical example, a thin film made of an oxide of indium and tin (ITO) is formed on a glass substrate. Are raised. The main application is a surface electrode of a viewing portion of a display panel, which is currently widely used for a liquid crystal display (LCD), an electroluminescence (EL) display, a plasma display panel (PDP), and the like. Recently, an organic electroluminescence (OEL) display and a field emission display (FED) have attracted attention as one of next-generation displays.

In recent years, the need for a large and small display panel has been greatly increased. To achieve 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, organic electroluminescent elements, which are being developed recently, are of a self-luminous type and are mainly developed for small portable terminals. Therefore, there is great expectation for lowering the resistance of transparent electrodes. In addition, a plasma display panel (PDP) that is currently spreading on the market and a field emission display (FE) that is being developed as a next-generation display
As for D), since they have a structure with high power consumption, there is great expectation for the development of low-resistance transparent electrodes.

[0004] In the case of a transparent electrode using ITO or the like, a heat treatment after film formation is performed in order to realize a low resistance. Processing temperatures range up to several hundred degrees Celsius.

[0005] When targeting a small portable terminal, it is necessary to reduce the weight of the transparent electrode itself. In order to reduce the weight of the transparent electrode, it is effective to reduce the weight of the base. For this reason, glass has conventionally been mainly used, but recently, a polymer molded article has been used.

[0006] Polymer molded articles generally have poor heat resistance.
For this reason, the heat treatment performed after the formation of the thin film in order to reduce the resistance of ITO or the like cannot be performed.

As a means for realizing a low-resistance transparent electrode without performing heat treatment, it is effective to use a transparent conductive thin film laminate. The transparent conductive thin film laminate is one in which a metal thin film having excellent conductivity is sandwiched between transparent high refractive index thin films.
The conductivity of the transparent conductive thin film laminate mainly depends on the conductivity of the metal thin film layer, and a high conductivity that cannot be realized by the conventional transparent conductive thin film can be obtained. This transparent conductive thin film laminate is very useful because it can be designed to have optimal optical and electrical characteristics according to the application by selecting the material and film thickness of each thin film layer.

[0008] When it is necessary to perform heat treatment on a glass molded body, the glass to be used is limited to a material having a high glass point transfer, and the choice of materials is narrowed. Such materials are usually expensive. Further, if the heat treatment step is present in the process, the productivity is lower than in the case where the heat treatment step is not performed.

In the case of a transparent electrode formed by laminating a transparent conductive thin film laminate in which silver or a silver alloy is sandwiched between high refractive index thin film layers on a transparent substrate, usually, a light wavelength of 450 nm to 650 is used.
The maximum wavelength of the transmittance exists between nm and the transmittance is usually much smaller than the maximum value in the shorter wavelength region and the longer wavelength region. When a light-emitting element is manufactured, a conventional transparent electrode has poor in-plane light emission uniformity when using a single transparent conductive thin film, and emits light in a wavelength range of 600 to 700 nm when using a transparent conductive thin film laminate. The brightness was poor.

[0010]

SUMMARY OF THE INVENTION The present invention has a wavelength 600
Provided is a transparent electrode using a transparent conductive thin film laminate having excellent light transmittance in the region of from about 700 nm to about 700 nm.
An object of the present invention is to provide a light emitting element having excellent light emission luminance in a region of 00 nm.

[0011]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, have reached the following means for solving the problems, and have reached the present invention.

(1) A transparent conductive thin film laminate (B) comprising a transparent high refractive index thin film layer (a) and a transparent metal thin film layer (b) made of silver or a silver alloy is laminated on a transparent substrate (A). A transparent electrode having a sheet resistance of 7 Ω / □ or more and 12 Ω / □ or less.

(2) The transparent electrode according to (1), wherein the light transmittance at each wavelength of 600 to 700 nm is from 70% to 99%.

(3) The transparent electrode according to (1), wherein the light transmittance at each wavelength of 600 to 700 nm is from 80% to 99%.

(4) The transparent electrode according to (1), wherein the light transmittance at each wavelength of 600 to 700 nm is 85% or more and 99% or less.

(5) The transparent electrode according to any one of (1) to (4), wherein the transparent substrate (A) is made of an organic polymer compound.

(6) The transparent electrode according to any one of (1) to (5), wherein the transparent substrate (A) is a glass molded substrate.

(7) The transparent conductive thin film laminate (B) comprises a transparent high refractive index thin film layer (a) and a transparent metal thin film layer (b). A transparent electrode (8), a transparent high refractive index thin film layer (a) on a transparent substrate (A),
The transparent metal thin film layer (b) made of silver or a silver alloy is formed in the order of A / a / b / a A / a / b / a / b / a A / a / b / a / b / a / b / a The transparent electrode according to any one of (1) to (7), which is laminated.

(9) The transparent high-refractive-index thin film layer (a) is made of an oxide mainly containing indium oxide, an oxide mainly containing zinc oxide, or an oxide mainly containing titanium oxide. The transparent electrode according to any one of (1) to (8).

(10) The transparent high-refractive-index thin film layer (a) is one of indium oxide containing an oxide and zinc oxide containing an aluminum oxide. The transparent electrode according to any one of the above.

(11) The transparent metal thin film layer (b) is an alloy of silver and a metal selected from gold, copper or palladium, according to any one of (1) to (10). Transparent electrode.

(12) The transparent metal thin film layer (b) is
An alloy of silver and gold containing 10 to 10% by weight, or
The transparent electrode according to any one of (1) to (11), which is an alloy of silver, palladium and copper containing palladium and copper at a ratio of 0.5 to 2% by weight.

(13) An organic electroluminescent device using the transparent electrode according to any one of (1) to (12).

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION The transparent electrode according to the present invention is characterized in that a transparent conductive thin film laminate (B) is laminated on a transparent substrate (A) and has a sheet resistance value. , 7Ω / □ to 12Ω / □, 600 to 70
The light transmittance at each wavelength of 0 nm is high, and the light emitting device of the present invention is excellent in in-plane light emission uniformity and light emission luminance uniformity for each wavelength.

[Transparent Substrate (A)] As the transparent substrate (A) used in the present invention, a film-like or plate-like material mainly composed of an organic polymer compound or glass is used. It is preferable to have a sufficient mechanical strength according to the above. Here, “excellent in transparency” means that the luminous transmittance is 40% or more in the thickness in the 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.

As the film-like transparent substrate, a polymer film is preferably used. Specifically, polyimide, polysulfone (PSF), polyethersulfone (PES), polyethylene terephthalate (PE)
T), polymethylene methacrylate (PMMA), polycarbonate (PC), polyetheretherketone (PEEK), polypropylene (PP), triacetylcellulose (TAC) and the like. Other suitable resins include random copolymers of ethylene and cyclic olefins, ring-opened polymers of cyclic olefins, or hydrogenated products of these ring-opened polymers or copolymers as shown in JP-A-9-40787, or These graft-modified products may be used. As another suitable resin, a (co) polymer of a vinyl-based monocyclic alicyclic hydrocarbon compound may be used.

Among them, polyethylene terephthalate (PE)
T) and triacetyl cellulose (TAC) are particularly preferably used.

There is no particular limitation on the thickness of the transparent substrate film. Usually, a material having a thickness of about 20 to 500 μm can be used.

Examples of the plate-shaped transparent substrate include a molded article made of an organic polymer compound or glass. A molded body made of an organic polymer compound is more preferably used because it is 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 suitably used because of its high transparency in a wide wavelength region and high mechanical strength.

The plate-shaped transparent substrate may be provided with a hard coat layer for the purpose of increasing the surface hardness or adhesion.

As the molded article made of glass used for the transparent substrate of the present invention, one having almost no surface warpage or scratches and excellent in thermal stability is generally used. For the active matrix drive system, alkali-free glass (white glass) is used because alkali elution from glass may greatly affect the performance of the active element. For the simple matrix drive system, inexpensive soda-lime glass (blue plate glass) can be used. The method for manufacturing a glass plate includes a float method, a download method, a fusion method, and the like. Alkali-free glass is produced using a download method or a fusion method, and soda-lime glass is produced using a float method.

The thickness of the plate-shaped transparent substrate is not particularly limited.
It suffices if sufficient mechanical strength and rigidity for maintaining flatness without bending are obtained. Usually, it is about 0.3 to 10 mm.

Further, a layer for improving gas barrier properties and a layer for improving solvent resistance may be formed on the surface of the transparent substrate. For the purpose of improving gas barrier properties, ethylene vinyl acetate compound (EVA),
A polyvinyl acetate compound (PVA) or the like is generally used, but is not limited thereto. For the purpose of improving the solvent resistance, a general hard coat layer is often used. Further, an antireflection layer or an antiglare layer may be formed on the surface of the transparent substrate.

[Transparent Conductive Thin Film Laminate (B)] The transparent conductive thin film laminate (B) in the present invention is a laminate of a transparent high refractive index thin film layer (a) and a metal thin film layer (b). Normal,
a / b / a, a / b / a / b / a, a / b / a / b / a
As shown in / b / a, it is used as a laminated structure sandwiching (b) in (a), and is used by being laminated on the transparent substrate (A).

The material used for the transparent high-refractive-index thin film layer (a) is preferably one having as high a transparency as possible. Here, “excellent in transparency” means that the film thickness is 100 n.
When a thin film of about m is formed, it indicates that the luminous transmittance of the thin film is 60% or more. The high-refractive-index material is a material having a refractive index for light of 550 nm of 1.4 or more. These may be mixed with impurities depending on the application.

Suitable for use as a transparent high refractive index thin film layer
An example of a material that can be used is the oxidation of indium and tin.
(ITO), oxide of cadmium and tin (CT
O), aluminum oxide (Al_TwoO_Three), Zinc oxide (Zn
O_Three), Oxides of zinc and aluminum (AZO), acids
Magnesium oxide (MgO), thorium oxide (Th
O_Two), Tin oxide (SnO)_Two), Lanthanum oxide (La
O_Two), Silicon oxide (SiO_Two), Indium oxide (I
n_TwoO_Three), Niobium oxide (Nb_TwoO_Three), Antimony oxide
(Sb _TwoO_Three), Zirconium oxide (ZrO)_Two), Oxide
Cium (CeO)_Two), Titanium oxide (TiO)_Two), Bis oxide
Trout (Bi_TwoO_Three).

Also, a transparent high refractive index sulfide may be used. Specific examples include zinc sulfide (ZnS), cadmium sulfide (CdS), and antimony sulfide (Sb ₂ S ₃ ).

Among these materials, ITO, Ti
O ₂ and AZO are particularly preferred. ITO and AZO have conductivity, and the refractive index in the visible region is as high as about 2.0, and has little absorption in the visible region.
TiO ₂ is an insulator and has a slight absorption in the visible region, but has a large refractive index for visible light of about 2.3.
There is no particular limitation on the percentage of tin contained in the ITO used. Usually, it is 50% by weight or less.

The ratio of aluminum contained in AZO used is not particularly limited. However, if the content ratio of aluminum is too low, the non-resistance value of the AZO film becomes too large. When laminated on the outermost surface, the contact resistance with the outside becomes too large, which is not preferable. When the content ratio of aluminum is too high, the transmittance of the AZO film,
In particular, the transmittance for light having a wavelength of 300 to 500 nm decreases, which is not preferable. Therefore, the ratio of aluminum contained in AZO is usually about 1 to 5 (% by weight).

The transparent electrode according to the present invention has two transparent high refractive index thin film layers (a). The transparent high refractive index thin film layer (a) located on the outermost surface is, for example, prepared when the device is manufactured. When an organic electroluminescence device was manufactured,
Since it is in direct contact with the organic layer, the magnitude of the electric resistance determines the emission luminance. For this reason, the material used for the transparent high refractive index thin film layer (a) located on the outermost surface preferably has a low specific resistance, and usually, ITO or AZO is suitably used.

The thickness of the transparent 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 0.5 to 100 nm.

The material of the metal thin film layer (b) used in the present invention is preferably a material having as high an electric conductivity as possible, and silver or a silver alloy is used. Silver is
It has a specific resistance of 1.59.times.10@-6 (.OMEGA..cm), and is most preferably used because it has the best electrical conductivity among all materials and the thin film has excellent visible light transmittance. However, silver has a problem in that it lacks stability when formed into a thin film and agglomerates. For this reason, a silver alloy is often used in order to increase the stability. Specific examples of the metal used for the silver alloy used include gold, copper, palladium, platinum, and indium. Among them, an alloy of silver and gold and an alloy of silver, palladium and copper are preferably used. The amount of metal contained in the silver to form the alloy depends on the application. If the amount is too small, the effect of increasing the stability cannot be obtained.

For example, a preferred gold content in an alloy of silver and gold is 3 to 10% by weight, and a preferred content of palladium and copper in an alloy of silver, palladium and copper is 0.5 to 2% by weight. .

The thickness of the metal thin film layer is determined in consideration of the transparency and electric conductivity of the entire transparent electrode. Usually, it is about 0.5 to 100 nm.

For the formation of the transparent high refractive index thin film layer and the metal thin film layer, conventionally known methods such as a vacuum deposition method, an ion plating method and a sputtering method can be used. Among them, the ion plating method or the sputtering method is used. It is preferably used. In the ion plating method, a desired metal or sintered body is resistance-heated in a reaction gas plasma or heated by an electron beam to perform vacuum deposition. In the sputtering method, a desired metal or a sintered body is used for a target, an inert gas such as argon or neon is used as a sputtering gas, and a gas necessary for a reaction is added to perform sputtering. For example, when an ITO thin film is formed, DC magnetron sputtering is performed in oxygen gas using an oxide of indium and tin as a sputtering target.

For the metal thin film layer, a vacuum evaporation method or a sputtering method is suitably used. In the vacuum evaporation method, a metal thin film can be easily formed by using a desired metal as an evaporation source and performing heating evaporation by resistance heating, electron beam heating, or the like. When a sputtering method 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 a DC sputtering method or a high-frequency sputtering method. Can be. In order to increase the deposition rate, a DC magnetron sputtering method or a high-frequency magnetron sputtering method is often used.

The atomic composition of the surface of the thin film layer of the transparent conductive thin film laminate manufactured by the above method is determined by Auger electron spectroscopy (AES), X-ray fluorescence (XRF), and X-ray microanalysis (XMA). , Charged particle excited X-ray analysis (R
BS), X-ray photoelectron spectroscopy (XPS), vacuum ultraviolet photoelectron spectroscopy (UPS), infrared absorption spectroscopy (IR), Raman spectroscopy, secondary ion mass spectroscopy (SIMS), low energy ion scattering spectroscopy (ISS). Further, the atomic composition and the film thickness in the film can be examined by performing Auger electron spectroscopy (AES) or secondary ion mass spectrometry (SIMS) in the depth direction.

The constitutional order of the transparent conductive thin film laminate, the crystal state of each layer, and the like can be examined by measuring the cross section with an optical microscope, a scanning electron microscope (SEM), or a transmission electron microscope (TEM). .

[Transparent electrode] The transparent electrode in the present invention comprises:
It is obtained by laminating a transparent high-refractive-index thin film layer (a) and a metal thin film layer (b) on a transparent substrate in a combination of film thicknesses that provide sufficient transmittance and surface resistance.

The higher the transmittance of the transparent electrode in the visible light region, the better. As in the present invention, in the case of a transparent electrode formed by laminating a transparent conductive thin film laminate sandwiching silver or a silver alloy between high refractive index thin film layers on a transparent substrate,
Usually, a maximum wavelength of transmittance exists between 450 nm and 650 nm of light, and in a shorter wavelength region and a longer wavelength region, the transmittance is usually smaller than the maximum value. However, it is preferable that the transmittance of that portion is as high as possible. That is, the light transmittance at each wavelength of 600 nm or more and 600 nm or less is preferably 60% or more and 99% or less, and more preferably 70% or less.
It is more preferably at least 99% and more preferably at least 75% and at most 99%.

The surface resistance is preferably as low as possible, but if the surface resistance is lowered, the transmittance cannot be maintained at a value required for practical use. The laminate having a practically sufficient transmittance and having no practical problem has a sheet resistance of 7Ω.
/ □ or more and 12Ω / □ or less.

The present invention will be described with reference to the drawings. FIG. 1 is a sectional view showing an example of the transparent electrode according to the present invention. Figure 1
In the above, a transparent electrode having a transparent high-refractive-index thin film layer (a) 20 and a metal thin film layer (b) 30 having a laminated structure A / a / b / a on a transparent polymer molded substrate (A) 10 is mentioned. I have. [Organic electroluminescence element] A light emitting element can be formed using the transparent electrode.

An organic electroluminescence device was prepared using the transparent electrode, and various evaluations were made.

In order to evaluate the uniformity of surface light emission, it is possible to prepare a planar light emitting element having a fixed area, divide the light emitting surface into several areas, and evaluate the light emission luminance in each area.

In order to evaluate the red light emission luminance,
A red light-emitting element can be manufactured and emission luminance can be measured.

A method for producing an organic electroluminescent element is obtained by laminating a hole transport layer, a light emitting layer and a cathode in a transparent electrode / hole transport layer / light emitting layer / cathode configuration on a transparent conductive thin film of a transparent electrode. Can be

The material used for the hole transport layer is, for example,
Diamine-based organic compounds are preferably used because of their excellent hole transporting ability. In particular, N, N'-diphenyl-N,
N ′-(3-methylphenyl) -1,1′-biphenyl-4,4′-diamine (abbreviated as TPD) has excellent hole transporting ability and is widely used as a hole transporting material.

The material used for the light emitting layer is, for example, 4-
(Dicyanomethylene) -2-methyl-6- (4-dimethylaminostyryl) -4H-pyran (abbreviation: DCM1)
N-vinylcarbazole (abbreviation: PVK), aluminum quinolinol complex (8-hydroxyquinoline aluminum) (abbreviation A)
lq3), 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-t-butylphenyl) -3,
4,9,10-perylenedicarboximide (abbreviated BP
PC).

The hole transport layer and the light emitting layer may be formed by physical vapor deposition such as conventionally known vacuum evaporation or ionization evaporation, or by dispersing a desired material in an appropriate solvent and spin coating. After applying by a method, a wet method of drying and the like may be used.

The thickness of each of the hole transport layer and the light emitting layer is usually 30 to 200 nm.

The material used for the cathode is an alloy of magnesium and silver, an alloy of magnesium and aluminum, and the like.

For forming these cathodes, a conventionally known physical film forming method such as a vacuum evaporation method or a sputtering method may be used.

The thickness of the cathode is usually about 5 to 500 nm.

Further, in order to further improve the luminous efficiency, an appropriate electron transport layer may be inserted between the luminescent layer and the cathode.

[0065]

Next, the present invention will be described in detail with reference to examples.

Example 1 A polyethylene terephthalate film [manufactured by Teijin Limited, model number HS] was used as the transparent substrate (A).
L, size 50 mm × 50 mm, thickness 188 μm].

Using a DC magnetron sputtering method, a thin film layer (a) made of an oxide of indium and tin and an alloy thin film layer (b) of silver, palladium and copper were formed on a transparent polymer molded substrate (A). A / a [thickness 40 nm] / b [thickness 9 nm] / a [thickness 40 nm] were laminated in this order to form a transparent electrode. The thin film layer composed of an oxide of indium and tin constitutes a transparent high refractive index thin film layer, and the alloy thin film layer of silver, palladium and copper constitutes a metal thin film layer. For the formation of a thin film layer composed of an oxide of indium and tin, as a target, an indium oxide-tin oxide sintered body [In2O3:
SnO2 = 90: 10 (weight ratio)], and a mixed gas of argon and oxygen (total pressure 266 mPa,
An oxygen partial pressure of 8 mPa) was used. Further, in forming an alloy thin film layer of silver, palladium and copper, an alloy of silver, palladium and copper [Ag: Pd: Cu = 99: 1: 1] was used as a target.
(Weight ratio)], and argon gas (total pressure 266 mPa) was used as a sputtering gas.

The sheet resistance of the transparent electrode obtained as described above was measured using a four-point needle resistance measuring device. Table 1 shows the measurement results. Further, the total light transmittance was measured using a spectrometer [model number U-3400 manufactured by Hitachi, Ltd.]
A total light transmission spectrum in the region of 00 nm was obtained.
Table 2 shows the measurement results. (Example 2) An alloy of silver and gold [Ag: Au =
95: 5 (weight ratio)]. At this time, an argon gas (total pressure of 266 mPa) was used as a sputtering gas. (Example 3) As a transparent high refractive index thin film layer (a), a zinc oxide-aluminum oxide sintered body [Zn
O: Al2O3 = 98: 2 (weight ratio)] and a thin film layer made of an oxide of zinc and aluminum was formed in the same manner as in Example 1. At this time, argon (total pressure of 266 mPa) was used as a sputtering gas. (Example 4) An alloy of silver and gold [Ag: Au =
95: 5 (weight ratio)], except that it was formed in the same manner as in Example 3. At this time, an argon gas (total pressure of 266 mPa) was used as a sputtering gas. (Example 5) As a transparent high-refractive-index thin film layer, a titanium oxide sintered body was used as a target, and a thin film layer made of titanium oxide was formed. At this time, an argon / oxygen mixed gas (total pressure: 266 mPa, oxygen partial pressure: 8 mPa) was used as a sputtering gas. (Example 6) A silver-gold alloy [Ag: Au =
95: 5 (weight ratio)]. At this time, an argon gas (total pressure of 266 mPa) was used as a sputtering gas. (Comparative Example 1) Using a DC magnetron sputtering method, a thin film layer (a) composed of an oxide of indium and tin was laminated on a transparent substrate (A) as A / a [130 nm thick], The same operation as in Example 1 was performed except that a transparent electrode was formed. (Examples 7 to 12) Using the transparent electrodes obtained in the above Examples 1 to 6, organic electroluminescent elements were manufactured, and a light emission test was performed.

First, 4- (dicyanomethylene) -2 was placed on the transparent conductive thin film of the transparent electrode obtained in Examples 1 to 6.
-Methyl-6- (4-dimethylaminostyryl) -4H
N-containing pyran (abbreviation: DCM1) at 2 mol%
A vinyl carbazole (PVK) film was formed from dichloroethane solution by dip coating [40 nm]. Subsequently, an 8-hydroxyquinoline aluminum (abbreviation: Alq3) layer [40 nm] was formed thereon using a vacuum heating evaporation method. Further, a magnesium layer [2 nm] was formed thereon as a cathode by using a vacuum heating evaporation method.

With respect to the organic electroluminescent device manufactured as described above, the light emitting area of 50 mm × 50 mm was divided into 25 squares of 10 mm × 10 mm square.

Except for one square area, the light emitting surface was covered with black paper so that light emission could be obtained only from the uncovered part.

Applying a DC voltage of 10 V between the anode and the cathode of the organic electroluminescent element to light it,
The emission luminance was measured using a luminance meter (LS-110 manufactured by Minolta).

A voltage was similarly applied to the remaining 24 square regions to emit light, and the luminance was measured. Table 3 shows the measurement results. (Examples 13 to 18) In the stage of performing the light emission test of the organic electroluminescence devices obtained in the above Examples 7 to 12, for each of them, the emission luminance from the entire surface was obtained without covering the black paper, and the wavelength was measured. 600-700n
Example 7 except that the emission luminance in the area of m was measured.
-12. The results are shown in Table 4. (Comparative Example 2) For forming a thin film layer composed of an oxide of indium and tin, indium oxide-tin oxide sintered body [In2O3: SnO2 = 90:10 (weight ratio)] was used as a target, and argon was used as a sputtering gas. At the stage of forming a transparent electrode using an oxygen mixed gas (total pressure: 266 mPa, oxygen partial pressure: 26 mPa) and performing a light emission test of the organic electroluminescence element, the light emission luminance from the entire surface is obtained without covering, and the wavelength The operation was performed in the same manner as in Example 1 except that the emission luminance in the region of 600 to 700 nm was measured. The above results are shown in Tables 1 to 4.

[0074]

[0075]

[Table 1]

[0076]

[Table 2]

[0077]

[Table 3]

[0078]

[Table 4]

The results in Tables 1 and 2 show that the transparent electrodes having a sheet resistance value significantly lower than that of Comparative Example 1 and having a high transmittance such as light having a wavelength of 600 to 700 nm were produced in all Examples. It indicates that there is. .

As can be seen from Table 3, the conventional organic electroluminescence element using a transparent electrode having a high sheet resistance and consisting of a single transparent conductive thin film as in Comparative Example 2 is different from the current introduction position in the transparent electrode. There was a problem that the luminance decreased as the distance increased, but when the transparent electrode in the area of the present invention was used, the sheet resistance was uniform over the entire area as in Examples 7 to 12. Emit light.

As can be seen from Table 4, the wavelengths of 600 to 70
The organic electroluminescent device using the transparent electrode having the transmittance in the region of 0 nm in the region specified by the present invention is a transparent electroconductive device as in Examples 13 to 18 as in Comparative Example 3. The light emission luminance at each wavelength of 600 to 700 nm is significantly higher than the case where a transparent electrode formed of a thin film laminate is used. (Examples 19 to 24) Instead of a polyethylene terephthalate film as a transparent substrate (A), a glass plate [manufactured by Corning, model number 7059, size 50 mm × 50 mm,
A transparent electrode was prepared and the sheet resistance was measured in the same manner as in Examples 1 to 6 except that a thickness of 1.1 mmt was prepared. Table 5 shows the results. (Comparative Example 4) The same operation as in Example 13 was performed based on Comparative Example 1. Table 5 shows the results. (Comparative Example 5) The same operation as in Comparative Example 3 was performed except that the prepared transparent electrode was subjected to a heat treatment at a temperature of 400 ° C for 1 hour. Table 5 shows the results. (Examples 19 to 24, Comparative Examples 4 and 5) The light transmittance in each wavelength region of 600 to 700 nm of the transparent electrodes produced by the above Examples and Comparative Examples was measured. Table 6 shows the results
Shown in (Examples 25 to 30, Comparative Examples 6 and 7)
Using the transparent electrodes prepared in Comparative Example 24 and Comparative Examples 4 and 5, organic electroluminescent devices were manufactured, and the light emission luminance of each device at each light emitting position was measured by the method of Example 7. Table 7 shows the results. (Examples 31 to 36, Comparative Examples 7 and 8) The emission luminance at 600 to 700 nm of the organic electroluminescent devices produced in Examples 25 to 30 and Comparative Examples 6 and 7 was measured without using a cover. Table 8 shows the results.

[0082]

[Table 5]

[0083]

[Table 6]

[0084]

[Table 7]

[0085]

[Table 8]

As can be seen from the results of Tables 5 and 6, the sheet resistance was significantly lower than that of Comparative Example 4 and the wavelength was 600 to 7
A transparent electrode having a high light transmittance at 00 nm could be produced in all the examples. As shown in Comparative Example 5, the sheet resistance was also reduced by subjecting the transparent electrode formed of a single transparent conductive thin film to heat treatment.

As shown in Comparative Example 6, a conventional organic electroluminescent device using a transparent electrode having a high sheet resistance and consisting of a single transparent conductive thin film emits light as the distance from the current introduction position in the transparent electrode increases. However, it can be seen that the use of the transparent electrode provided by the present invention makes it possible to emit light uniformly over the entire region as shown in Examples 25 to 30.

Further, by heating a transparent electrode formed of a single transparent conductive thin film as in Comparative Example 5, a transparent electrode having the same sheet resistance as that obtained in Examples 19 to 24 of the present invention was obtained. Although the electrode could be manufactured, the light transmittance at a wavelength of 600 to 700 nm was
The results were lower than those of all the examples in the present invention. Further, in this case, since a step of heating is added, it is not preferable in consideration of productivity as compared with the embodiment.

As shown in Table 8, when an organic electroluminescent device was manufactured using the transparent electrodes prepared in Comparative Examples 7 and 8, the emission luminance in the wavelength region of 600 to 700 nm was shown in Examples 31 to 36. Further, the level was not attained when the transparent electrode of the present invention was used. In this case, the light emission luminance was not uniform depending on the position.

[0090]

According to the present invention, by laminating a specific transparent conductive thin film laminate on a transparent substrate made of an organic polymer compound or glass, the sheet resistance is low, and
High transparency with a light transmittance in the range of 00 nm was obtained.
The present invention provides an organic electroluminescence device having excellent in-plane emission uniformity and emission brightness in a range of 600 to 700 nm by using a transparent electrode having a low sheet resistance and a high light transmittance in a range of 600 to 700 nm. A typical light-emitting element can be manufactured.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of a transparent electrode.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Transparent base material (A) 20 Transparent high refractive index thin film layer (a) 30 Silver or silver alloy thin film layer (b)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C23C 14/08 C23C 14/08 C G09F 9/30 339 G09F 9/30 339Z H05B 33/14 H05B 33/14 A 33/28 33/28 F term (reference) 3K007 AB02 AB04 AB18 CA01 CA06 CB00 CB04 DA01 DB03 EB00 4K029 AA09 AA11 AA24 BA03 BA10 BA15 BA17 BA18 BA44 BA45 BA48 BA49 BA50 BC08 BC09 BD02 CA01 CA05 DC03 DC04 DC09 5A09A A07A EB02 FB12 FB18 JA11 5G307 FA01 FA02 FB01 FB02 FC07 FC09

Claims (11)

[Claims] 1. A transparent conductive thin film laminate (B) comprising a transparent high refractive index thin film layer (a) and a transparent metal thin film layer (b) made of silver or a silver alloy is laminated on a transparent substrate (A). Yes,
A transparent electrode having a sheet resistance of 7 Ω / □ or more and 12 Ω / □ or less. 2. The transparent electrode according to claim 1, wherein the light transmittance at each wavelength of 600 to 700 nm is from 70% to 99%. 3. The transparent electrode according to claim 1, wherein the transparent substrate (A) is made of an organic polymer compound. 4. The transparent electrode according to claim 1, wherein the transparent substrate (A) is a glass molded substrate. 5. The transparent electrode according to claim 1, wherein the transparent conductive thin film laminate (B) comprises a transparent high refractive index thin film layer (a) and a transparent metal thin film layer (b). 6. A transparent high-refractive-index thin film layer (a) and a transparent metal thin film layer (b) made of silver or a silver alloy are formed on a transparent substrate (A) by A / a / b / a A / a / b / a. The transparent electrode according to any one of claims 1 to 5, wherein the transparent electrode is laminated in the order of / b / a A / a / b / a / b / a / b / a. 7. The transparent high-refractive-index thin film layer (a) is made of an oxide containing indium oxide as a main component, an oxide containing zinc oxide as a main component, or an oxide containing titanium oxide as a main component. The transparent electrode according to claim 1. 8. The transparent high-refractive-index thin film layer (a) is one of indium oxide containing oxide and zinc oxide containing aluminum oxide.
8. The transparent electrode according to any one of items 1 to 7. 9. The transparent electrode according to claim 1, wherein the transparent metal thin film layer (b) is an alloy of silver and a metal selected from gold, copper or palladium. . 10. The transparent metal thin film layer (b) comprises gold of 3-10.
4. An alloy of silver and gold containing at a ratio of 0.5% by weight or an alloy of silver, palladium and copper containing 0.5 to 2% by weight of palladium and copper. 10. The transparent electrode according to any of 9. 11. An organic electroluminescence device using the transparent electrode according to claim 1. Description: