TWI460853B - A transparent conductive film for organic EL and an organic EL element using the transparent conductive film - Google Patents

Description

Transparent conductive film for organic EL and organic EL element using the same

The present invention relates to a transparent conductive film used in an organic electroluminescence (EL) display device and an organic EL device using the transparent conductive film.

In general, an organic EL display device is provided with an anode and a cathode on both sides of an electroluminescent layer containing an organic EL layer on a TFT active matrix substrate of a TFT (thin film transistor) in which a switching element is disposed. The organic EL element has a structure formed on each pixel region.

Conventionally, in the organic EL device, a metal film of Al or an Al alloy or a metal film of Ag or an Ag alloy is used as a metal film of an anode. A transparent conductive film such as ITO (Indium Tin Oxide) or AZO (Aluminum doped Zinc Oxide) is provided between the metal film and the electric field light-emitting layer. The transparent conductive film is provided for the purpose of preventing diffusion of sulfur (S) components contained in the electric field light-emitting layer to the metal film.

[Practical Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2006-236839

[Non-patent literature]

[Non-Patent Document 1] Kobe Steel Technology News / Vol.57 No.1 (Apr. 2007)

The following problems remain in the above conventional techniques.

In other words, the ITO used in the transparent conductive film between the metal film and the electric field light-emitting layer has a problem that the contact resistance with the Al metal film is high (see Non-Patent Document 1). Therefore, when AZO having a low contact resistance can be obtained for a metal film of Al or an Al alloy, the reflected light from the metal film may have a low transmittance in a short-wavelength region (wavelength of 380 nm or less) of visible light. Disadvantages.

In view of the above, the present invention provides a transparent conductive film for organic EL which has a low contact resistance with a metal film of Al or an Al alloy, and which has a good transmittance in a short-wavelength region, and a transparent conductive film using the transparent conductive film. Organic EL elements are for the purpose.

In order to solve the above problems, the present invention adopts the following configuration. In other words, the transparent conductive film for organic EL of the present invention is a transparent conductive film formed between an electric field light-emitting layer containing an organic EL layer of an organic EL element and a metal film of Al or an Al alloy, which is characterized by a metal component. The content ratio of the elements is formed by an Al-Mg-Zn-based oxide having an atomic ratio of Al: 0.7 to 7%, Mg: 10 to 25%, and residual Zn.

The transparent conductive film for organic EL is formed by a ratio of a metal component element to an Al-Mg-Zn-based oxide having an atomic ratio of Al: 0.7 to 7%, Mg: 10 to 25%, and residual Zn. When Al is contained, a contact resistance lower than that of ITO can be obtained for a metal film of Al or an Al alloy, and a high transmittance in a short wavelength region can be obtained when compared with AZO.

Here, the reason why the content ratio of the metal component element in the transparent conductive film for organic EL of the present invention is limited to the above range is as follows.

Al:

Al is added because it has an effect of improving the conductivity of the transparent conductive film. When the content is less than 0.7 atomic%, the effect of improving the conductivity is insufficient. When the content of Al exceeds 7 atom%, the carrier concentration is increased. Since the transparency of the transparent conductive film is lowered, it is not desirable. In addition, the content ratio of Al or Al alloy which is contained in all the metal component elements contained in the transparent conductive film of the present invention is set to Al: 0.7 to 7 atom%.

Mg:

Since 10% by atom or more of Mg is used as the metal component element in the transparent conductive film, the bonding gap can be controlled in the range of 3.5 to 4.2 eV depending on the content, so that the short-wavelength light can be improved. Transparency. Further, by adding Mg, it is possible to prevent an excessive concentration of the carrier from increasing in the film, and it is also possible to improve the transparency to near-infrared rays. In addition, when the Mg content is more than 25 atom%, the conductivity of the transparent conductive film is remarkably lowered in the presence of moisture and oxygen, so the content ratio of Mg in all the metal component elements is set to Mg: 10 to 25 atom%. .

Further, the transparent conductive film for an organic EL of the present invention is characterized in that it further contains an Al-Mg-Ga-Zn-based oxide in an atomic ratio of Ga: 0.015 to 0.085%.

In other words, since the transparent conductive film for organic EL further contains When the atomic ratio is Ga: 0.015 to 0.085% and is formed of an Al-Mg-Ga-Zn-based oxide, it is more excellent than an Al-Mg-Zn-based oxide transparent conductive film to which no Ga is added. As a result of the moisture resistance, there is little possibility that the specific resistance increases due to the presence of moisture or oxygen in the use environment, and deterioration of film characteristics as a transparent conductive film can be suppressed, and deterioration of element characteristics can be prevented.

Here, the reason why the content ratio of the Ga component in the transparent conductive film for organic EL of the present invention is limited to the above range is as follows.

Ga:

By containing 0.015 atomic % or more of Ga as a metal component element in the transparent conductive film, the transparency of the film can be prevented and the bonding gap can be maintained, and the deterioration of conductivity in a high-temperature and high-humidity environment can be suppressed, and Ga When the content is more than 0.085%, the conductivity of the film (before film formation, before high temperature and high humidity test) is lowered, and the conductivity of the transparent conductive film is insufficient, so that all the metal component elements contained in the transparent conductive film are included. The content ratio of Ga is set to Ga: 0.015 to 0.085 atom%.

The organic EL device of the present invention comprises an anode, an electroluminescent layer containing an organic EL layer formed on the anode, and an organic EL device having a cathode formed on the electroluminescent layer, characterized in that the anode is A metal film having Al or an Al alloy, and the above-described transparent conductive film for an organic EL of the present invention formed between the metal film and the electroluminescent layer.

In other words, since the organic EL element has the above-described transparent conductive film for organic EL of the present invention formed between the metal film of Al or an Al alloy and the electroluminescent layer, it can be driven at a low voltage by a low contact resistance while borrowing High transparency makes it possible to produce high brightness in a wide range including short wavelength regions.

The following effects can be achieved by the present invention.

In other words, the transparent conductive film for organic EL of the present invention has an atomic ratio of Al: 0.7 to 7%, Mg: 10 to 25%, and a residual portion of Zn Al-Mg-Zn-based oxide. When formed, low contact resistance can be obtained and high transmittance in a short wavelength region can be obtained. In addition, when a small amount of Ga as a metal component element is contained, the Al-Mg-Ga-Zn-based oxide transparent conductive film is formed, and when compared with the Al-Mg-Zn-based oxide transparent conductive film containing no Ga, With better moisture resistance, there is little chance that the specific resistance will increase due to the presence of moisture and oxygen in the environment.

Further, by using the organic EL element of the transparent conductive film of the present invention, good electrical characteristics can be obtained and high luminance in a wide wavelength range can be obtained, and further, by containing Ga, film deterioration can be suppressed and suppressed over a long period of time. The case where the luminous efficiency is lowered.

[In order to implement the invention]

In the following, an embodiment of the transparent conductive film for an organic EL of the present invention and an organic EL device including the film will be described with reference to FIG.

The transparent conductive film 1 for organic EL of the present embodiment is connected to Al or Al in the electric field light-emitting layer 2 of the organic EL element 10 as shown in Fig. 1 . The transparent conductive film formed between the metal film 3 of gold is characterized in that the ratio of the content of the metal component element is Al: 0.7 to 7%, Mg: 10 to 25%, and Al-Mg of the residual portion of Zn. A film formed of a Zn-based oxide.

In addition, the transparent conductive film 1 for organic EL further contains a film formed of an Al-Mg-Ga-Zn-based oxide in an atomic ratio of Ga: 0.015 to 0.085%.

Further, the organic EL element 10 of the present embodiment includes the anode 5 formed on the film formation substrate 4, the electric field light-emitting layer 2 including the organic EL layer 2b formed on the anode 5, and the light-emitting layer at the electric field. The organic EL device of the cathode 6 formed on the layer 2 is characterized in that the anode 5 is a metal film 3 having Al or an Al alloy, and the above-mentioned organic EL formed between the metal film 3 and the electric field light-emitting layer 2 Transparent conductive film 1.

The thickness of each of the above layers and films is, for example, 100 to 200 nm for the electric field light-emitting layer 2, 10 to 20 nm for the transparent conductive film 1 for organic EL, and 100 nm for the metal film 3.

The electric field light-emitting layer 2 has a three-layer structure in which a hole transport layer 2a, an organic EL layer 2b, and an electron transport layer 2c are sequentially laminated on the anode 5.

Further, the organic polymer material (hole injection and transport material) constituting the hole transport layer 2a has the ability to transport holes, has a hole injection effect from the anode 5, and has an effect on the organic EL layer 2b or the luminescent material. The excellent hole injection effect is excellent, and it is preferable to prevent the urging agent generated in the organic EL layer 2b from moving toward the electron transport layer 2c, and a compound having excellent film forming ability.

Specifically, for example, a phthalocyanine derivative, a naphthalocyanine derivative, a porphyrin derivative Biological, oxazole, oxadiazole, triazole, imidazole, imidazolidone, thioimidazole, pyrazoline, pyrazolone, tetrahydroimidazole, hydrazine, hydrazino, polyarylalkane, anthracene, butadiene , benzidine type triphenylamine, styrylamine type triphenylamine, diamine type triphenylamine, and the like, derivatives of the like, polyvinyl carbazole, polydecane, etc., polyethylene dioxythiophene / polystyrene sulfonate A polymer material such as a typical conductive polymer such as acid (PEDOT/PSS) or polyaniline/camphorsulfonic acid (PANI/CSA).

The luminescent material used in the organic EL layer 2b, for example, an olefin-based luminescent material such as 4,4'-(2,2-diphenylvinyl)biphenyl or 9,10-bis(2-naphthyl)anthracene, 9,10-bis(3,5-diphenylphenyl)anthracene, 9,10-bis(9,9-dimethylindenyl)anthracene, 9,10-(4-(2,2-diphenyl) Vinyl)phenyl)anthracene, 9,10'-bis(2-biphenylyl)-9,9'-biguanide, 9,10,9',10'-tetraphenyl-2,2'- Lanthanide-based luminescent materials such as bis-indenyl, 1,4-bis(9-phenyl-10-indenyl)benzene, 2,7,2',7'-fluorene (2,2-diphenylvinyl) Spiral-based luminescent materials such as spiral bismuth, 4,4'-dicarbazolylbiphenyl, azole-based luminescent materials such as 1,3-dioxazolylbenzene, 1,3,5-trimethylbenzene, etc. The fluorene-based luminescent material is a typical low molecular luminescent material, polyphenylene vinylene, polyfluorene, polyvinyl carbazole, etc., which are typical polymer luminescent materials.

The organic EL layer 2b may be doped with a fluorescent pigment or may be doped with a phosphorescent pigment.

Electron injection used in the electron transport layer 2c. The material is transported to have the ability to transport electrons, has an electron injection effect from the cathode 6, has an excellent electron injection effect on the organic EL layer 2b or the luminescent material, and prevents the stimulator generated in the organic EL layer 2b from being electrically charged. The hole injection layer moves, A compound excellent in film forming ability is preferred. Specifically, for example, anthrone, quinone dimethane, diphenyl hydrazine, pyran sulphur dioxide, oxazole, oxadiazole, triazole, imidazole, stilbene tetracarboxylic acid, fluorenylene methane, quinodimethane, fluorenone And such derivatives.

The transparent conductive film 1 for an organic EL is an oxide sputtering target formed by a ratio of a metal component element to an atomic ratio of Al: 0.7 to 7%, Mg: 10 to 25%, residual Zn, or The atomic ratio is Al: 0.7 to 7%, Mg: 10 to 25%, Ga: 0.015 to 0.085%, and an oxide sputtering target formed by residual Zn is formed by DC sputtering or pulsed DC sputtering.

The specific resistance of the transparent conductive film 1 for organic EL is about 1×10 ^-3 Ω. Cm.

Here, the reason why the composition of the sputtering target is as described above is as follows.

Al:

Since it contains 0.7 atom% or more of Al, it has an effect of increasing the carrier density and the amount of hole movement of the transparent conductive film obtained by sputtering, and improving the conductivity of the film, but the content is less than 0.7 atomic %, or more than 7 When the atomic % is used, the conductivity of the transparent conductive film is lowered, which is not desirable. Therefore, Al contained in the sputtering target for forming a transparent conductive film is set to 0.7 to 7 atom%.

Mg:

The Mg is effective for adjusting the bonding gap of the transparent conductive film obtained by sputtering, improving the transparency to short-wavelength light, and improving the transparency to the near-infrared wavelength. When the content of Mg is less than 10 atom%, a sufficient effect of adjusting the bonding gap cannot be obtained, and the effect of improving the transparency of the film at a short wavelength is insufficient. When the Mg content exceeds 25 atom%, the conductivity of the film is remarkably lowered. Therefore, the Mg contained in the sputtering target for forming a transparent conductive film is set to 10 to 25 atom%.

Ga:

Ga is effective for improving the moisture resistance of the transparent conductive film. When the content of Ga is less than 0.015 atom%, the effect of improving the moisture resistance of the film is insufficient, and when the content of Ga exceeds 0.085 atom%, the electric resistance of the film remarkably increases. Therefore, the Ga contained in the sputtering target for forming a transparent conductive film is set to be 0.015 to 0.085 atom%.

Further, the content ratio of the metal component element is an oxide sputtering target formed by atomic ratio of Al: 0.7 to 7%, Mg: 10 to 25%, Ga: 0.015 to 0.085%, and residual Zn, since the target can be used. The volume resistance is suppressed to 0.1Ω. Since it is less than cm, it can be formed into a high-quality transparent conductive film at a high speed by DC or pulsating DC sputtering.

The sputtering target for forming a transparent conductive film can be produced, for example, by the following method. Here, a production example of an oxide sputtering target containing Ga is described as an example.

First, weigh. Al ₂ O ₃ powder, MgO powder, Ga ₂ O ₃ powder and ZnO powder having a purity of 99.9% or more and an average primary particle diameter of 5 μm or less are used as raw material powders, and are pulverized by wet ball milling to have an average particle diameter of 0.1~. After 3.0 μm, vacuum drying was carried out at 80 ° C for 5 hours. Next, the dried mixed powder can be filled in a mold of black lead, and is carried out in a vacuum at a temperature of 700 to 1300 ° C, 0.5 to 5 hours, and a pressing force of 100 to 350 kgf/cm ² . By sputtering, a sputtering target for forming a transparent conductive film was produced.

Preferred sputtering conditions for sputtering are as follows.

First, the relative density of the sputtering target is preferably 90% or more, and when the relative density is less than 90%, the film quality of the obtained film is lowered in addition to the film formation rate. The relative density of the sputtering target is preferably 95% or more, and more preferably 97% or more.

Further, the purity of the sputtering target is preferably 99% or more. When the purity is less than 99%, the conductivity or chemical stability of the resulting film is lowered due to impurities. Further, the purity of the sputtering target is preferably 99.9% or more, and more preferably 99.99% or more.

In addition, when a sputtering process is performed using the above-described sputtering target, a film formation substrate (hereinafter referred to as a "film formation substrate") and a sputtering target are placed in a vacuum chamber of the sputtering apparatus, and the adsorption target is removed. The moisture of the film-forming substrate, the sputtering target, and the like is preferably used.

The removal of the water can be carried out, for example, by vacuum removal after the vacuum chamber reaches a vacuum pressure of 5 x 10 ^-4 Pa or less. It is preferable to carry out heating between vacuum removals, and by this heating, moisture removal can be performed more reliably, and the time of vacuum removal can be shortened. When the vacuum pressure at this time is less than 5x10 ^-4 Pa or less, the moisture adsorbed on the device, the film formation substrate, the sputtering target, and the like is likely to be insufficiently removed, so that the density of the obtained film is lowered, and The conductivity and moisture resistance of the film are affected. Further, it is preferable that the exhaust system of the sputtering apparatus to be used has a water trap or an oxygen absorbing agent for removing moisture.

After the vacuum evacuation described above, the film formation of the transparent conductive film is carried out, and the degree of vacuum at the time of film formation is preferably 1 x 10 ^-2 to 1 x 10 ⁰ Pa. When the sputtering gas pressure is less than 1 x 10 ^-2 Pa (lower than 1 x 10 ^{- 2} Pa), the discharge stability at the time of film formation is lowered, and when it exceeds 1 x 10 ⁰ Pa, it is difficult to increase the applied voltage applied to the sputtering target. . The sputtering gas pressure at the time of film formation is preferably 0.1 to 1 x 10 ⁰ Pa.

Further, the DC output force at the time of film formation is preferably 1 W/cm ² or more and 10 W/cm ² or less. When the output force exceeds 10 W/cm ² , the denseness of the obtained film is lowered, and it is difficult to obtain a highly moisture-resistant transparent conductive film. Secondly, the output force at the time of film formation is preferably 3 to 10 W/cm ² . Further, the voltage at the time of film formation is preferably from 100 to 400V.

In the gas atmosphere at the time of film formation, generally, even if only argon gas (Ar gas) is used, a sufficiently high transparent film can be obtained, but a mixed gas of argon gas (Ar gas) and oxygen gas (O ₂ gas) can also be used. The mixing ratio of Ar gas and O ₂ gas varies depending on the oxidation state of the sputtering target used or the degree of vacuum and output force at the time of film formation, except when the volume concentration of O ₂ gas in the gas environment exceeds 5%. The conductivity of the obtained film is liable to lower. Further, the volume concentration of the O ₂ gas in the gas atmosphere at the time of film formation is preferably 5% or less, more preferably 3% or less.

The substrate temperature at the time of film formation can be appropriately selected from the range of 50 ° C to the heat-resistant temperature of the film-forming substrate, but when the substrate temperature exceeds 200 ° C, most The resin substrate exceeds its heat-resistant temperature, and the types of substrates that can be used are greatly limited. Further, when the substrate temperature is less than 50 ° C, the denseness of the obtained film is lowered, and a highly moisture-resistant transparent conductive film is not easily obtained. Therefore, the substrate temperature at the time of film formation is preferably 50 to 200 ° C, and 80 to 200. °C is better, best at 100~200°C.

In the film formation substrate 4, for example, when an organic EL device is formed on a TFT substrate, an insulating substrate such as a glass substrate or a heat resistant resin substrate in which a plurality of insulating films such as an SiO ₂ film of a SiN film or a gate insulating film are laminated thereon is used. .

The transparent conductive film 1 for an organic EL of the present embodiment is characterized in that the content ratio of the metal component element is Al-Mg-Zn oxidation in an atomic ratio of Al: 0.7 to 7%, Mg: 10 to 25%, and residual Zn. When the substance is formed, when Al is contained, a low contact resistance with respect to the Al or Al alloy metal film 3 can be obtained when compared with ITO, and a high transmittance can be obtained in a short wavelength region when compared with AZO.

Further, in the organic EL element 10 of the present embodiment, the transparent conductive film 1 for organic EL is formed between the metal film 3 of Al or an Al alloy and the electroluminescent layer 2, and can be driven with low resistance by a low contact resistance. And by high transparency, high brightness can be obtained in a wide range including short wavelength regions.

An example of the transparent conductive film for organic EL which is actually formed on the basis of the above-described embodiment is described below.

[Examples]

First, a sputtering target for forming a film of a transparent conductive film for organic EL of the present invention containing Ga will be described.

Weighing according to the certain composition shown in Table 1. An Al ₂ O ₃ raw material powder having a purity of 99.9% or more and an average particle diameter of 0.4 μm, a MgO raw material powder having a purity of 99.9% or more and an average particle diameter of 1 μm, a Ga ₂ O ₃ raw material powder having a purity of 99.9% or more and an average particle diameter of 0.3 μm, and a purity of 99.9. ZnO raw material powder having an average particle diameter of 0.4 μm or more is used as a raw material powder. The powder to be blended was placed in a polyethylene bottle, and ball-milled using a zirconia ball having a diameter of 3 mm, and the average primary particle diameter of the mixed powder was pulverized to 0.3 μm or less (however, the solvent used in the ball mill was ethanol, and no dispersion was added. The agent or other auxiliary agent was subjected to atmospheric drying of the slurry reaching the target average particle diameter, and then vacuum-dried at 80 ° C for 5 hours.

The dried mixed powder was filled in a black lead mold, and subjected to vacuum hot pressing under the conditions of a certain sintering temperature and sintering time shown in Table 1, and a pressing force of 350 kgf/cm ^{2 to} prepare a diameter of 165 mm x a thickness of 9 mm. After the sintered body, a sputtering target for forming a transparent conductive film shown in Table 1 having a diameter of 152.4 mm x a thickness of 6 mm was produced by mechanical processing (Examples 1 to 6 are shown below).

Then, by mixing the raw material powders shown in Table 1, the raw material powder containing no Ga ₂ O ₃ component was prepared, and the sputtering targets of Examples 7 to 10 were produced in the same manner as in the above-described Examples 1 to 6. .

Moreover, as shown in Table 1, the content of at least one of Al and Mg is not adjusted. In the raw material powders within the scope of the present invention, sputtering targets of Comparative Examples 1 to 4 were produced in the same manner as in the above-described Examples 1 to 6.

In the comparison, a sputtering target of Conventional Examples 1 to 3 used for forming a conventional transparent conductive film for organic EL of ITO and AZO was prepared.

The AZO sputtering targets of Conventional Examples 1 and 2 were made using the same raw material powder as in the above examples, and were weighed according to a certain composition shown in Table 1. Cooperate. The blended powder was placed in a ball mill (bead mill), and ball-milled using a zirconia ball having a diameter of 1 mm, and the average primary particle diameter of the mixed powder was pulverized to 0.3 μm or less. The solvent used is water. When the target average primary particle diameter is reached, an adhesive (PVA) is added to the slurry, and dried and granulated by a spray dryer, and then molded by press molding to produce a molded body. The obtained molded body was sintered in an oxygen gas atmosphere under the conditions shown in Table 1, and subjected to mechanical polishing to prepare a sputtering target.

The ITO sputtering target of the conventional example 3 is weighed by a certain composition shown in Table 1. An Sn ₂ raw material powder having a purity of 99.9% or more and an average particle diameter of 0.3 μm, and an In ₂ O ₃ raw material powder having a purity of 99.9% or more and an average particle diameter of 0.4 μm were blended. The pulverization, mixing, and molding of the particles were carried out in the same manner as in Conventional Examples 1 and 2. The obtained molded body was sintered in an oxygen gas atmosphere under the conditions shown in Table 1, and subjected to mechanical polishing to prepare a sputtering target.

The theoretical density ratio, the specific resistance, and the content of the metal element were determined for each of the sputtering targets of Examples 1 to 10, Comparative Examples 1 to 4, and Conventional Examples 1 to 3 obtained as described above. The theoretical density ratio refers to the ratio of the oxide sintered body density to the theoretical density, and the theoretical density refers to the composition of the sintered body raw material and its crystalline structure. Number, the density that is guided when there are no defects such as holes at all. The sintered body density is measured by weight and size, and is calculated by calculation.

Further, the specific resistance was determined by measuring Loresta by a four-probe resistance manufactured by Mitsubishi Gas Chemical Co., Ltd. Further, the content of the metal element is obtained by taking an analytical sample from the sputtering target and quantitatively measuring it by the ICP method (high frequency induction combined with plasma method).

The above values are shown in Table 1.

Next, the production of a transparent conductive film for organic EL will be described.

Each of the sputtering targets of Examples 1 to 10, Comparative Examples 1 to 4, and Conventional Examples 1 to 3 was bonded to a copper sintered plate using In, and sputtering was performed using a sputtering apparatus to make the organic EL shown in Table 2 A transparent conductive film is formed into a film.

The sputtering conditions of the present examples, comparative examples, and conventional examples of Table 2 are all the same. The sputtering pressure reached 5x10 ^-4 Pa at the time of sputtering, the Ar gas pressure at the time of sputtering was 0.67 Pa, and the substrate temperature was in the range of room temperature to 250 °C. Further, the power source used for sputtering is a direct current (DC) power source RPG-50 manufactured by MKS Corporation of Japan. The input power density was 8 W/cm ² . Further, the substrate was made of alkali-free glass (Corning Corporation 1737#). The abnormal discharge during sputtering and the sputtering state after sputtering are shown in Table 2.

The content of the metal component in the film was determined by using a sputtering film as an analytical sample by inductively coupled plasma luminescence spectrometry (ICP method) [using a machine: SPS-1500VR (manufactured by Seiko Electronics Co., Ltd.)]. Table 2 shows the content of the metal component elements.

Moreover, the film characteristics (light transmittance, moisture resistance) of each of the transparent conductive films of the examples, the comparative examples, and the conventional examples were observed.

The obtained transparent conductive film for organic EL, the film thickness is controlled by a stylus The method [Using a machine: DEKTAK3030 (manufactured by Sloan Co., Ltd.)] was used, and the specific resistance was determined by measuring a four-probe resistance meter Loresta by Mitsubishi Gas Chemical. The light transmittance of the film was determined by a spectroscopic method [using a machine: U-3210 (manufactured by Hitachi, Ltd.)]. In Table 2, the light transmittances of light wavelengths of 350 nm and 900 nm are shown.

The moisture resistance evaluation of the film is based on the evaluation of the moisture resistance test based on the evaluation of the organic EL element, and the film specific resistance after being placed in a high-temperature and high-humidity atmosphere of 80 ° C and 85% RH for 1000 hours, by Mitsubishi Gas Chemical Co., Ltd. The four-probe resistance measuring device Loresta was used for the measurement. Table 3 shows the respective characteristic values.

Secondly, in order to measure the contact resistance, the Al film is sputtered in the glass. A film was formed on the substrate at 150 nm, and a transparent conductive film of 100 nm was formed thereon using the targets of the examples, the comparative examples, and the conventional examples. Further, the laminated film was heat-treated at 150 ° C for 30 minutes in a vacuum, and then the contact resistance was measured by the following TLM (Transmission Line Model) method, as shown in Table 4. The contact resistance is 0.01Ω. More than cm is evaluated. 0.01Ω. The contact resistance of cm or more is not required as an organic EL device.

In the TLM method, an electrode pair of a plurality of resistor electrodes having different electrode intervals is formed on a semiconductor substrate, and a resistance is measured for each electrode pair. Then, the measured resistance is plotted on the coordinates with the electrode spacing as the horizontal axis and the resistance as the vertical axis, and the slope of the similar straight line is obtained from the plotted points, and the contact resistance is obtained from the slice. .

Comparing the film characteristics of Tables 3 to 4, it is understood that the transmittances of short wavelengths of 350 nm in Examples 1 to 10 are all 90% or more, and Comparative Examples 1 and 2 and Conventional Examples 1 to 3 are less than 90%. . In addition, the specific resistance of the film is 10 mΩ with respect to Examples 1 to 10 before the moisture resistance test. Below cm, the comparative examples are all 100mΩ. More than cm. 100mΩ. The specific resistance of cm or more is not suitable as a transparent conductive film for organic EL. In addition, regarding the moisture resistance test, the films of Examples 1 to 10 were all 350 mΩ. Below cm, Comparative Examples 1, 2 and the conventional examples 1, 2 are 1000 mΩ. Above cm, Comparative Examples 2 and 3 also exhibited high specific resistance.

The contact resistance with the Al film is less than 10 ^-2 Ω with respect to Examples 1 to 10. For the value of cm, Comparative Examples 1 to 4 and Conventional Example 3 are 10 ^-2 Ω. The value above cm. 10 ^-2 Ω. The contact resistance characteristics above cm are not suitable as a transparent conductive film for organic EL.

Further, the technical scope of the present invention is not limited to the above-described embodiments and the above-described embodiments, and various modifications can be made without departing from the spirit and scope of the invention.

[Industry use value]

As described above, the transparent conductive film for an organic EL of the present invention is suitable as an organic EL device because of its low contact resistance compared with ITO and high transmittance in a short wavelength region when compared with AZO. A transparent conductive film on a metal film of Al or an Al alloy. In other words, when the transparent conductive film for organic EL of the present invention is used for an organic EL device, since high electrical characteristics can be obtained and high luminance can be obtained in a wide wavelength region, it is possible to An element to be a pixel of an organic EL display device which constitutes high luminance with low power.

1‧‧‧Transparent conductive film for organic EL

2‧‧‧Electroluminescent layer

3‧‧‧Metal film of Al or Al alloy

4‧‧‧ film forming substrate

5‧‧‧Anode

6‧‧‧ cathode

10‧‧‧Organic EL components

[Fig. 1] A typical cross-sectional view showing a structure of an organic EL device in an embodiment of a transparent conductive film for an organic EL of the present invention and an organic EL device including the film.

1‧‧‧Transparent conductive film for organic EL

2‧‧‧Electroluminescent layer

2a‧‧‧ hole transport layer

2b‧‧‧Organic EL layer

2c‧‧‧Electronic transport layer

3‧‧‧Metal film of Al or Al alloy

4‧‧‧ film forming substrate

5‧‧‧Anode

6‧‧‧ cathode

10‧‧‧Organic EL components

Claims (3)

A transparent conductive film for organic EL, which is a transparent conductive film formed between an electroluminescent layer of an organic EL layer containing an organic EL element and a metal film of Al or an Al alloy, characterized by a content ratio of a metal component element It is formed by an Al-Mg-Zn-based oxide having an atomic ratio of Al: 0.7 to 7%, Mg: 10 to 25%, and a residual portion of Zn. The transparent conductive film for organic EL according to the first aspect of the invention, which further comprises an Al-Mg-Ga-Zn-based oxide in an atomic ratio of Ga: 0.015 to 0.085%. An organic EL device comprising an anode, an electroluminescent layer containing an organic EL layer formed on the anode, and an organic EL element having a cathode formed on the electroluminescent layer, wherein the anode has Al Or a metal film of an Al alloy, and a transparent conductive film for an organic EL according to the first aspect of the invention, which is formed between the metal film and the electroluminescent layer.