JP2009231278A - Method for manufacturing organic el element, organic el display, and organic el lighting - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an organic electroluminescent element in which an organic layer between electrodes is deposited by a wet type deposition method and a short circuit of the element is limited and a stable luminance of the element is materialized. <P>SOLUTION: After a deposition process by a wet type deposition method, if an angle θ between the upper surface of an organic layer and a horizontal surface is 0° when an upper surface of a deposited organic layer is made parallel with the horizontal surface, the upper surface of the organic layer is kept so that it makes an angle θ 0°-100° against the horizontal surface. After the wet deposition, the organic layer of which the solvent is removed by heat-drying, a plenty of pores are kept inside a membrane, and a structural relaxation occurs in a molecular level while being stored. At this time, if the deposited surface is put to face upward, along with the structural relaxation, caving-in of a membrane surface is apt to occur toward a pore region inside the membrane and, as a result, a flatness of the deposited surface is damaged, and a device in which such a damaged layer is used is risked to invite luminance unevenness of emitted light and shortened service life. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a method for manufacturing an organic electroluminescence (EL) device having an organic layer formed by a wet film formation method.
The present invention also relates to an organic EL display and an organic EL illumination using the organic electroluminescent element manufactured by the method for manufacturing the organic electroluminescent element.

  An organic electroluminescent element is usually provided by laminating a plurality of organic layers (light emitting layer, hole injection layer, hole transport layer, electron transport layer, etc.) between an anode and a cathode. In many cases, the layer is formed by vacuum-depositing a low molecular weight organic layer forming material.

  However, it is difficult to obtain a uniform thin film with few defects by vacuum deposition, and it takes a long time to form a plurality of organic layers by vacuum deposition. there were. In particular, it has been demanded to solve these problems in terms of performance and efficiency toward the enlargement of the screen of the organic EL display.

  Therefore, for example, Patent Document 1 reports a technique for forming an organic layer of an organic electroluminescent element by a wet film forming method. However, the organic electroluminescent element having an organic layer formed by a wet film forming method has problems such as that stable luminance cannot be obtained and a short circuit of the element occurs.

JP-A-2005-78896

  The present invention relates to a method for producing an organic electroluminescent device having an organic layer formed by a wet film-forming method, a method for producing an organic electroluminescent device having a short brightness of the device and having a stable luminance, and the organic electric field. It is an object to provide an organic EL display and an organic EL illumination using a light emitting element.

  As a result of intensive studies, the present inventors have found that the above problem can be solved by depositing an organic layer by a wet film formation method and then storing the organic layer under specific conditions, and have reached the present invention.

  That is, the present invention provides a method for producing an organic electroluminescent device having an organic layer formed by at least one layer of wet film forming method between two electrodes, wherein the organic layer is formed by a wet film forming method. A film process, and a storage process for storing the film after film formation. The storage process includes an angle θ between the upper surface of the organic layer and the horizontal plane when the upper surface of the formed organic layer faces downward in parallel to the horizontal plane. Is 0 °, the method is a method of storing an organic electroluminescent device, wherein the angle θ between the upper surface of the organic layer and the horizontal plane is stored as 0 ° to 100 °.

  The present invention also resides in an organic EL display and an organic EL illumination using the organic electroluminescent element produced by the method for producing an organic electroluminescent element.

According to the present invention, an organic electroluminescence device having a stable luminance with less short-circuiting of devices can be produced by a wet film formation method.
In addition, since the device characteristics can be obtained stably, the yield in device manufacture is improved. Moreover, the area can be easily increased, and the organic electroluminescence device can be used for a large display or illumination.

It is a typical sectional view explaining horizontal crossing angle theta concerning the present invention. It is typical sectional drawing which shows an example of the organic electroluminescent element manufactured by the method of this invention. It is typical sectional drawing which shows the layer structure of the organic electroluminescent element produced in the Example. It is typical sectional drawing which shows the layer structure of the organic electroluminescent element produced in the Example.

  Embodiments of the present invention will be described in detail below. However, the description of the constituent elements described below is an example (representative example) of an embodiment of the present invention, and the present invention is not limited to these contents. Not.

  The method for producing an organic electroluminescent element of the present invention is a method for producing an organic electroluminescent element having an organic layer formed by a wet film-forming method of at least one layer between two electrodes. A film forming step for forming a film by a method, and a storage step for storing the film after forming the film. The storage step includes an upper surface of the organic layer when the upper surface of the formed organic layer faces downward in parallel to a horizontal plane. When the angle θ between the upper surface of the organic layer and the horizontal plane is 0 °, the angle θ between the upper surface of the organic layer and the horizontal plane is stored as 0 ° to 100 °.

  In the present invention, the organic layer provided between the two electrodes of the organic electroluminescent element may be composed of a single layer or may be a laminate of a plurality of organic layers. Further, at least one of the organic layers between the two electrodes may be an organic layer formed by a wet film forming method, and when a plurality of organic layers are provided between two electrodes, the wet film forming method may be used. The layer other than the organic layer to be formed may be a layer formed by a wet film forming method or a layer formed by a vacuum vapor deposition method.

In an organic electroluminescence device, two electrodes are an anode and a cathode, and usually one of the anode and the cathode is formed on a substrate, an organic layer is laminated thereon, and the anode and the cathode are laminated on the laminated organic layer. The other is formed.
In the organic electroluminescence device, at least one of these organic layers is a light emitting layer. Examples of other organic layers include a hole injection layer, a hole transport layer, a hole blocking layer, an electron transport layer, and an electron injection layer. Usually, these organic layers are formed directly on the electrodes or on other layers formed on the electrodes, but the production method of the present invention may be applied to any of these organic layers. However, it is preferably applied to a hole injection layer or a light emitting layer, and particularly preferably applied to an organic layer formed on an electrode such as a hole injection layer.

[Method for forming organic layer]
First, the method for forming an organic layer according to the present invention will be described.

As described above, in the present invention, at least one organic layer between the electrodes is formed by a wet film forming method.
In the present invention, the wet film forming method is a spin coating method, a dip coating method, a die coating method, a bar coating method, a blade coating method, a roll coating method, a spray coating method, a capillary coating method, an ink jet method, a screen printing method, a gravure. A wet film formation method such as a printing method or a flexographic printing method.

  In the present invention, the step of forming the organic layer includes a film formation step by a wet film formation method and a storage step of storing the formed organic layer after film formation. Usually, the film formation step and the storage step There is a drying step between.

1-1. Film-forming process The film-forming process can be carried out with any change as long as the effects of the present invention are not significantly impaired. However, in general, in the film formation step, a composition containing a material for the organic layer formed by a wet film formation method and a solvent (hereinafter sometimes referred to as “coating composition” as appropriate) is formed. The film is formed by coating the surface, that is, the electrode or another organic layer formed on the electrode in the form of a film.

1-1-1. Coating composition The solvent used in the coating composition is not limited as long as it does not significantly impair the effects of the present invention, but is usually selected from aliphatic hydrocarbon solvents and aromatic hydrocarbon solvents. Examples of the solvent include ether solvents and ester solvents.

  Examples of ether solvents include aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate (PGMEA); 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole , Aromatic ethers such as phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2,4-dimethylanisole, and diphenylether.

  Examples of the ester solvent include aliphatic esters such as ethyl acetate, n-butyl acetate, ethyl lactate, and n-butyl lactate; phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, and benzoic acid. aromatic esters such as n-butyl; and the like.

  These may be used alone or as a mixed solvent of two or more.

  Examples of solvents that can be used in addition to the ether solvents and ester solvents described above include aromatic hydrocarbon solvents such as benzene, toluene, xylene, methicylene, cyclohexylbenzene, tetralin, chlorobenzene, dichlorobenzene, and trichlorobenzene. ; Alkanes such as n-decane, cyclohexane, ethylcyclohexane, decalin, bicyclohexane; alicyclic ketones such as cyclohexanone, cyclooctanone, and fenkon; alicyclic alcohols such as cyclohexanol and cyclooctanol; methyl ethyl ketone, dibutyl; Aliphatic ketones such as ketones; Aliphatic alcohols such as butanol and hexanol; Amide solvents such as N, N-dimethylformamide and N, N-dimethylacetamide; Dimethyl sulfoxide and the like It is. In addition, these may use only 1 type and may use 2 or more types by arbitrary combinations and a ratio. Moreover, you may use 1 type (s) or 2 or more types among these solvents in combination with 1 type (s) or 2 or more types among the above-mentioned ether solvent and ester solvent.

  Among the solvents described above, a solvent having a high ability (solvent ability) to dissolve the material of the organic layer formed by the wet film forming method is preferable. This is because the concentration of the organic layer material in the coating composition can be set arbitrarily to prepare a coating composition having a concentration excellent in the efficiency of the film forming process.

  The concentration of the organic layer material in the coating composition is not limited as long as the effects of the present invention are not significantly impaired, but is usually 0.01% by weight or more, preferably 0.1% by weight or more, and more preferably 0. 0.5 wt% or more, and usually 70 wt% or less, preferably 60 wt% or less, more preferably 50 wt% or less. If this concentration is too large, film thickness unevenness may occur, and if it is too small, defects may occur in the film.

  In addition, since an organic electroluminescent element is normally formed by laminating | stacking the layer (organic layer) containing many organic compounds, it is preferable that each layer is a uniform layer. Here, when a layer is formed by a wet film formation method, if a certain amount or more of water is present in the coating composition for forming each organic layer, moisture is mixed into the coating film and the uniformity of the film is impaired. The water content in the coating composition is preferably as low as possible. In general, since organic electroluminescent elements use many materials such as cathodes that deteriorate significantly due to moisture, the presence of moisture is preferably as small as possible from the viewpoint of preventing element degradation. For the above reasons, the amount of water contained in the coating composition is usually 1% by weight or less, preferably 0.1% by weight or less.

  Examples of methods for reducing the amount of water in the coating composition include the use of a nitrogen gas seal, the use of a desiccant, the dehydration of the solvent in advance, and the use of a solvent with low water solubility. Can be mentioned. Among these, from the viewpoint of preventing the phenomenon that the coating film absorbs moisture in the air and whitens when applying the coating composition, it is preferable to use a solvent having low water solubility. Specifically, in the coating composition, a solvent having low water solubility, for example, a solvent having water solubility at 25 ° C. of 1% by weight or less, preferably 0.1% by weight or less, is added to the entire coating composition. On the other hand, it is preferably contained in a concentration of usually 10% by weight or more, especially 30% by weight or more, particularly 50% by weight or more.

1-1-2. Film Forming Method The wet film forming method in the film forming process is not limited as long as the effects of the present invention are not significantly impaired. For example, spin coating method, dip coating method, die coating method, bar coating method, blade coating method, roll coating method, spray coating method, capillary coating method, ink jet method, screen printing method, gravure printing method, flexographic printing method, etc. Can be mentioned.
Among these film forming methods, a spin coating method, a spray coating method, and an ink jet method are preferable. This is because the liquid property specific to the coating composition used for the organic electroluminescent element is matched.

1-1-3. Film-forming temperature The film-forming temperature in the film-forming process is not limited as long as the effect of the present invention is not significantly impaired, but is preferably 10 ° C. or higher, more preferably 13 ° C. or higher, further preferably 16 ° C. or higher, and 50 ° C. or lower. Is preferable, 40 ° C. or lower is more preferable, and 30 ° C. or lower is further preferable. This is to suppress the formation of crystals in the coating composition.

1-1-4. Film-forming humidity The relative humidity in the film-forming process is not limited as long as the effect of the present invention is not significantly impaired, but is usually 0.01 ppm or more, preferably 0.05 ppm or more, more preferably 0.1 ppm or more, and usually 80%. Below, it is preferably 60% or less, more preferably 15% or less, still more preferably 1% or less, and particularly preferably 100 ppm or less. If the relative humidity is too low, it may be difficult to control film forming conditions in the wet film forming process. On the other hand, if it is too large, moisture adsorption on the organic layer may be easily affected.

1-1-5. Oxygen concentration The volume concentration of oxygen in the atmosphere in the film forming step is not limited as long as the effect of the present invention is not significantly impaired, but is preferably 0.01 ppm or more, more preferably 0.05 ppm or more, and preferably 50% or less. More preferably, it is 25% or less, more preferably 1% or less, and particularly preferably 100 ppm or less. An environment in which the oxygen concentration is too low is difficult to control. If the oxygen concentration is too high, oxygen diffuses inside the organic layer, which may adversely affect device characteristics.

1-1-6. Number of Particles The number of fine particles in the film forming environment (that is, the number of particles) is not limited as long as the effects of the present invention are not significantly impaired. From the viewpoint of reducing dark spots, particles having a particle size of 0.5 μm or more are 1 m ^3. Usually 10,000 or less, preferably 5,000 or less. Particularly preferably, the number of particles having a particle diameter of 0.3 μm or more is 5000 or less per 1 m ³ . Although there is no restriction | limiting in this lower limit, from a viewpoint of industrial practicality, it can be considered that there are usually 100 particles having a particle diameter of 0.3 μm or more per 1 m ³ . If the number of particles is too large, dark spots may occur, and environmental control tends to become more difficult as the number falls below the above range.
The number of fine particles is detected by a light scattering method, and can be detected by, for example, a handheld particle counter KR (manufactured by Lion Co., Ltd.).

1-1-7. Film thickness The film thickness of the organic layer formed in the film forming process (film thickness before the drying process described later) is not limited as long as the effect of the present invention is not significantly impaired, but is preferably 10 nm or more, more preferably 15 nm or more, More preferably, it is 20 nm or more, Preferably it is 30 micrometers or less, More preferably, it is 20 micrometers or less, More preferably, it is 15 micrometers or less. This is because high film thickness accuracy can be obtained within this range.
The film thickness accuracy is defined as the ratio between the maximum value and the minimum value of the film thickness of the light emitting portion (the organic layer portion sandwiched between the anode and the cathode). The film thickness accuracy is measured with a contact film thickness meter or an interference film thickness meter.

1-2. Drying Step After the film formation step, the film of the coating composition formed is usually dried. Hereinafter, an example of a drying process will be specifically described.

1-2-1. Drying method The method for drying the formed coating composition is not limited as long as the effects of the present invention are not significantly impaired. Specific examples include heat treatment, reduced pressure treatment, inert gas treatment, sputtering treatment, and the like.
Among these, heat treatment is preferable. This is because the residual solvent in the film can be easily reduced.
Note that the above processing may be performed alone or in combination. When combining a plurality of processes, the processes may be performed in an arbitrary order, or all or a part of the processes may be performed in parallel.
However, it is preferable to perform drying under conditions that do not cause uneven drying.

  In order to prevent foreign matter from entering during the drying process, the drying process is preferably performed in a clean room.

The method of heat treatment in the drying step is not limited as long as the effects of the present invention are not impaired, and can be arbitrarily changed and carried out.
As a specific method of the heat treatment, for example, an in-furnace bake method in which a substrate (a substrate on which an organic layer film is formed by a wet film forming method) is placed in a heating furnace (bake furnace) and the coating film is heated, A hot plate method in which a substrate is mounted on a plate (hot plate) and the coating film is heated through the plate. A heater is arranged on the upper surface side and / or lower surface side of the substrate, and electromagnetic waves (for example, infrared rays) are emitted from the heater. Then, a method of heating the thin film, and the like can be mentioned. Of these, the plate (hot plate) method is preferable. This is because the solvent in the film can be volatilized uniformly.

The method of the decompression process in the drying step is not limited as long as the effect of the present invention is not impaired, and can be arbitrarily changed and implemented.
As a specific method of the decompression process, for example, a method in which a base material is disposed in a sealable chamber and the inside of the chamber is decompressed to volatilize the solvent is exemplified.

1-2-2. Drying temperature The drying temperature in the drying step is not limited as long as the effects of the present invention are not significantly impaired. When heat treatment is performed, it is usually 50 ° C or higher, preferably 80 ° C or higher, and usually 300 ° C or lower, preferably 250 ° C or lower. It is. If the temperature is too high, the other layers may be adversely affected. If the temperature is too low, the solvent may remain in the film.

  The drying temperature refers to the atmospheric temperature in the case of the in-furnace baking method, the plate temperature in the case of the hot plate method, and the atmospheric temperature in the case of the method using a heater.

1-2-3. Drying time The drying time in the drying step is not limited as long as the effect of the present invention is not significantly impaired, but is preferably 30 seconds or more, more preferably 1 minute or more, further preferably 2 minutes or more, and preferably 5 hours or less, More preferably, it is 2 hours or less, More preferably, it is 1 hour or less. If the drying time is too long, the components of the other layers tend to diffuse, and if it is too short, the film tends to be inhomogeneous. Further, drying may be performed in a plurality of times.

1-2-4. Relative humidity The relative humidity in the drying step is not limited as long as the effects of the present invention are not significantly impaired, but preferably 1% or more, more preferably 5% or more, still more preferably 10% or more, and preferably 80% or less. More preferably, it is 50% or less, More preferably, it is 20% or less. If the relative humidity is too high, moisture tends to remain in the film.

1-2-5. Degree of vacuum The degree of vacuum in the drying step is not limited as long as the effects of the present invention are not significantly impaired. However, when a reduced pressure treatment is performed, it is preferably 1 × 10 ⁻² Pa or less, more preferably 1 × 10 ⁻³ Pa or less. More preferably, it is 5 × 10 ⁻⁴ Pa or less. Although there is no restriction | limiting in the lower limit of a vacuum degree, Usually, it is 1 * 10 < ^-5 > Pa or more. If the degree of vacuum is too high, it takes time to increase the degree of vacuum, and environmental control tends to be difficult during that time. If it is too low, the solvent tends to remain in the film.

1-2-6. Film thickness after the drying step The film thickness of the organic layer after the drying step is not limited as long as the effect of the present invention is not significantly impaired, but is preferably 10 nm or more, more preferably 15 nm or more, further preferably 20 nm or more, Preferably it is 300 nm or less, More preferably, it is 200 nm, More preferably, it is 150 nm or less. If the film thickness is too small, defects may occur in the thin film. In addition, if the film thickness is too large, the influence of element characteristics may increase due to film thickness unevenness.

1-2-7. Film thickness accuracy after the drying step The film thickness accuracy of the coating composition after the drying step is preferably 500% or less, more preferably 300% or less, still more preferably 200% or less, and preferably 2%. Above, more preferably 5% or more, still more preferably 8% or more. If the film thickness accuracy is too large, device characteristics such as uneven light emission tend to be unstable, and if it is too small, film defects tend to occur, and the film quality tends to be non-homogeneous. The method for measuring the film thickness accuracy is the same as the method described above.

1-3. Storage Process The storage process may be performed immediately after the film formation process described above, but is usually performed after the drying process described above after the film formation process.

  The angle formed by the upper surface of the organic layer and the horizontal plane in this storage step will be described with reference to FIG. In FIG. 1, reference numeral 11 denotes a substrate. The substrate 11 indicates a film formation target on which the organic layer 12 is formed by a wet film formation method, and is usually a film formation target of the present invention. Illustrations of electrodes and other organic layers provided below a certain organic layer are omitted. For example, when the organic layer 12 is a hole injection layer, at least an anode is formed between the organic layer 12 and the substrate 11, but in FIG. 1, it is formed below these organic layers. The illustration of the layers is omitted.

  FIG. 1A is a diagram showing a state in which an organic layer 12 is formed on a substrate 11 by a wet film forming method. As shown in FIG. 1 (a), the organic layer is normally formed by a wet film formation method in which the substrate 11 is placed horizontally, that is, the angle between the surface of the substrate 11 and the horizontal plane is approximately 0 °. Thus, the substrate 11 is installed, and the organic layer 12 is formed on the upper surface of the substrate 11 with a predetermined film thickness by the above-described wet film forming method. Here, “substantially 0 °” usually includes a slight inclination of ± 3 ° or less.

After the organic layer 12 is formed by the wet film formation method in this manner, preferably, the formed coating film is further subjected to the above-described drying step, and then the substrate 11 is rotated for storage, so that FIG. ), An angle θ (hereinafter sometimes referred to as “horizontal crossing angle θ”) formed by the upper surface of the organic layer (deposition surface of the organic layer 12 on the side opposite to the substrate 11) 12A and the horizontal plane is 0. The upper surface 12A is directed downward (this downward direction is the downward direction in the vertical direction), vertical (when the horizontal crossing angle θ = 90 °), or slightly upward (90 °) so that the angle is 100 ° to 100 °. ° <θ ≦ 100 °).
Here, the horizontal crossing angle θ of 0 ° is an angle when the upper surface of the formed organic layer faces downward and the upper surface of the organic layer is parallel to the horizontal plane.

The details of the reason why an element having a short circuit and a high luminance can be obtained by storing the horizontal crossing angle θ at 0 ° to 100 ° in this way is not clear, but is presumed as follows.
That is, after the wet film formation, the organic layer from which the solvent has been removed by drying such as heating has a large number of voids inside the film. However, structural relaxation occurs at the molecular level while it is preserved.
At this time, if the film formation surface is turned upward, the film surface tends to be depressed toward the void region inside the film with the structural relaxation.
As a result, the flatness of the film formation surface is impaired, and a device manufactured using the film may cause uneven luminance of light emission or a decrease in life.
On the other hand, when the upper surface of the formed organic layer is stored downward or substantially vertical as in the present invention, it is presumed that a decrease in flatness of the film surface based on the mechanism as described above can be avoided.
In addition, the effect of greatly reducing the possibility that particles scattered in the storage atmosphere adhere to or enter the film formation surface can be expected.

  The storage in the present invention means that a certain time (the following storage time) is the above state (the state of horizontal crossing angle θ = 0 ° to 100 °), and the horizontal crossing angle θ = 0 ° in a stationary state. It may be kept at ˜100 °, or it may be kept at a horizontal crossing angle θ = 0 ° to 100 ° in any moving process, but it usually means that it is kept stationary.

1-3-1. Horizontal crossing angle θ
The horizontal crossing angle θ during storage may be 0 ° to 100 °, preferably 45 ° or more, more preferably 60 ° or more, preferably 90 ° or less, more preferably 85 ° or less, and even more preferably 75 °. It is as follows. By setting it within this range, it is possible to obtain an element having a high luminance with few element short circuits.
From the viewpoint of productivity (space and the like), it is also preferable to store the horizontal crossing angle θ at 0 to 30 ° or 60 to 100 °.

1-3-2. Support method at the time of storage As the method of setting the horizontal crossing angle θ to 0 ° to 100 °, any method may be used. For example, a substrate support can be used.
The substrate support may be any support as long as it can support the substrate on which the organic layer is formed, or can be maintained at a certain angle, and may have a structure such as a slide glass stand. In particular, it is preferable in terms of productivity to use a support having a multilayer structure that can support a plurality of substrates on which an organic layer is formed.
Further, for example, a storage tool that can set the horizontal crossing angle θ to 0 ° to 100 ° by gripping the substrate as described in JP-A-8-8319 may be used.
These supports and gripping tools are usually made of materials such as stainless steel, polycarbonate, Teflon and polypropylene, and it is preferable to use materials having antistatic properties.

1-3-3. Storage temperature The storage temperature in the storage step is not limited as long as the effect of the present invention is not significantly impaired, but is usually 10 ° C or higher, preferably 15 ° C or higher, more preferably 20 ° C or higher, usually 100 ° C or lower, preferably 50 ° C or lower. More preferably, it is 30 degrees C or less, More preferably, it is 25 degrees C or less. If the storage temperature is too high, the film quality may be deteriorated, and if it is too low, there is a risk of particle adhesion due to condensation or charging.

1-3-4. Storage humidity The relative humidity in the storage process is not limited as long as the effect of the present invention is not significantly impaired, but is preferably 0.01 ppm or more, more preferably 0.05 ppm or more, further preferably 0.08 ppm or more, and preferably 60. % Or less, more preferably 50% or less, further preferably 10% or less, and particularly preferably 1% or less. If the relative humidity is too low, there is a tendency that it is difficult to control the environment to be constant, and there is a possibility that the device cannot be stably manufactured. If the relative humidity is too high, moisture may be physically adsorbed on the surface of the organic layer.

1-3-5. Storage time The storage time in the storage process is not limited as long as the effect of the present invention is not significantly impaired, but is preferably 100 hours or less, more preferably 50 hours or less, even more preferably 5 hours or less, particularly preferably 1 hour or less, especially Preferably, it is 30 minutes or less, preferably 10 seconds or more, more preferably 30 seconds or more, and particularly preferably 1 minute or more. If the storage time is too short, the effects of the present invention may not be obtained. However, if the storage time is too long, production efficiency is impaired.

1-3-6. Atmosphere The atmosphere in the storage step is not limited as long as the effects of the present invention are not significantly impaired, but may be air, a vacuum environment, an inert gas environment, or an oxygen-containing atmosphere.
In the case of a vacuum environment, the degree of vacuum is preferably 1 × 10 ⁻² Pa or less, more preferably 1 × 10 ⁻³ Pa or less, and there is no particular lower limit, but 1 × 10 ⁻⁵ Pa or more is preferable. If the degree of vacuum is too high, it takes time to increase the degree of vacuum, and environmental control during that time tends to be difficult.
Examples of the inert gas include nitrogen gas, noble gases, nonflammable gases, and the like. In addition, only 1 type may be used for an inert gas and it may use 2 or more types together by arbitrary combinations and a ratio.
In the case of an oxygen-containing atmosphere, the atmosphere usually contains oxygen and nitrogen, and the oxygen concentration in the atmosphere is preferably 1% by volume or more, more preferably 10% by volume or more, and particularly preferably 18% by volume or more. And preferably 50% by volume or less, more preferably 30% by volume or less, and particularly preferably 25% by volume or less.

1-4. Step of forming organic layer on organic layer through storage step Another organic layer can be formed on the organic layer formed by a wet film formation method and subjected to the storage step. The other organic layer may be formed by a wet film forming method or may be formed by other methods such as a vapor deposition method.

Hereinafter, the vapor deposition method will be described.
A vapor deposition method can be used when forming any layer among the organic layers which an organic electroluminescent element has. The organic layer formed by the vapor deposition method may be a single layer, or may be a laminate of a plurality of layers.

  Formation of the organic layer by vapor deposition is preferably performed under the following conditions and methods.

1-4-1. Pressure The pressure in the vapor deposition step is not limited as long as the effect of the present invention is not significantly impaired, but is preferably 1 × 10 ⁻⁷ Pa or more, more preferably 5 × 10 ⁻⁷ Pa or more, and further preferably 1 × 10 ⁻⁶ Pa. Above, particularly preferably 5 × 10 ⁻⁶ Pa or more, preferably 1 × 10 ⁻² Pa or less, more preferably 1 × 10 ⁻³ Pa or less, still more preferably 0.5 × 10 ⁻³ Pa or less, It is preferably 1 × 10 ⁻⁴ Pa or less. When the pressure is outside this range, the membrane tends to be inhomogeneous.

1-4-2. Temperature The temperature in the vapor deposition step is not limited as long as the effect of the present invention is not significantly impaired, but is preferably 15 ° C. or higher, more preferably 20 ° C. or higher, further preferably 30 ° C. or higher, and preferably 300 ° C. or lower, more preferably Is 200 ° C. or lower, more preferably 150 ° C. or lower. If the temperature is too high, the components of the other layers tend to diffuse, and if it is too low, the film tends to be inhomogeneous.
Here, the temperature refers to the temperature of the substrate (or the organic electroluminescent element being manufactured).

1-4-3. Deposition rate The deposition rate is not limited as long as the effect of the present invention is not significantly impaired, but is preferably 0.001 nm / s or more, more preferably 0.005 nm / s or more, further preferably 0.01 nm / s or more, Preferably it is 8 nm / s or less, More preferably, it is 7 nm / s or less, More preferably, it is 1 nm / s or less. If the deposition rate is too fast, it tends to be difficult to control the film thickness, and if it is too slow, the smoothness of the film tends to be impaired. Further, the deposition rate may be changed continuously.

1-4-4. Vapor deposition method The method of forming the organic layer by vapor deposition is not particularly limited, but for example, a vapor deposition source is placed in a crucible or metal boat installed in a vacuum vessel, and the vacuum vessel is evacuated to an appropriate pressure. Thereafter, the crucible or metal boat is heated to evaporate, and an organic layer is formed on the organic electroluminescent element that is being manufactured and is placed facing the crucible or metal boat.

[Configuration of organic electroluminescent element]
Below, the layer structure of the organic electroluminescent element manufactured by the method of the present invention, the general formation method thereof, and the like will be described with reference to FIG.

FIG. 2 is a schematic cross-sectional view showing a structural example of an organic electroluminescence device manufactured by the method of the present invention. In FIG. 2, 1 is a substrate, 2 is an anode, 3 is a hole injection layer, and 4 is a hole. The transport layer, 5 represents a light emitting layer, 6 represents a hole blocking layer, 7 represents an electron transport layer, 8 represents an electron injection layer, and 9 represents a cathode.
In addition, in such an organic electroluminescent element, when the organic layer between the anode 2 and the cathode 9 is formed by a wet film forming method, the material of each layer described below is dispersed or dissolved in a solvent as described above. Thus, a coating composition may be prepared, and a film may be formed using this coating composition.

{substrate}
The substrate 1 serves as a support for the organic electroluminescent element, and a quartz or glass plate, a metal plate or a metal foil, a plastic film, a sheet, or the like is used. In particular, a glass plate or a transparent synthetic resin plate such as polyester, polymethacrylate, polycarbonate, polysulfone or the like is preferable. When using a synthetic resin substrate, it is necessary to pay attention to gas barrier properties. If the gas barrier property of the substrate is too small, the organic electroluminescent element may be deteriorated by the outside air that has passed through the substrate, which is not preferable. For this reason, a method of providing a gas barrier property by providing a dense silicon oxide film or the like on at least one surface of the synthetic resin substrate is also a preferable method.

{anode}
The anode 2 serves to inject holes into the layer on the light emitting layer side.
This anode 2 is usually a metal such as aluminum, gold, silver, nickel, palladium, platinum, a metal oxide such as an oxide of indium and / or tin, a metal halide such as copper iodide, carbon black, or It is composed of a conductive polymer such as poly (3-methylthiophene), polypyrrole, or polyaniline.

  In general, the anode 2 is often formed by a sputtering method, a vacuum deposition method, or the like. In addition, when forming the anode 2 using fine metal particles such as silver, fine particles such as copper iodide, carbon black, conductive metal oxide fine particles, and conductive polymer fine powder, an appropriate binder resin solution It is also possible to form the anode 2 by dispersing it and applying it onto the substrate 1. Furthermore, in the case of a conductive polymer, a thin film can be directly formed on the substrate 1 by electrolytic polymerization, or the anode 2 can be formed by applying a conductive polymer on the substrate 1 (Appl. Phys. Lett. 60, 2711, 1992).

  The anode 2 usually has a single-layer structure, but it can also have a laminated structure made of a plurality of materials if desired.

  The thickness of the anode 2 varies depending on the required transparency. When transparency is required, the visible light transmittance is usually 60% or more, preferably 80% or more. In this case, the thickness of the anode 2 is usually 5 nm or more, preferably 10 nm or more, and is usually 1000 nm or less, preferably about 500 nm or less. When it may be opaque, the thickness of the anode 2 is arbitrary, and the anode 2 may be the same as the substrate 1. Furthermore, it is also possible to laminate different conductive materials on the anode 2 described above.

  For the purpose of removing impurities adhering to the anode 2 and adjusting the ionization potential to improve the hole injection property, the surface of the anode 2 is treated with ultraviolet (UV) / ozone, or with oxygen plasma or argon plasma. It is preferable to do.

{Hole injection layer}
The hole injection layer 3 is a layer that transports holes from the anode 2 to the light emitting layer 5, and is usually formed on the anode 2.
Hereinafter, components contained in the hole injection layer 3 will be described first, and then a method for forming the hole injection layer 3 will be described.

<Material of hole injection layer>
The material of the hole injection layer 3 is contained in the hole injection layer 3. When the hole injection layer 3 is formed by a wet film forming method, a positive hole injection layer forming coating composition (hereinafter sometimes referred to as a “hole injection layer composition”) is added to the positive electrode. The material of the hole injection layer is contained. The material of the hole injection layer 3 is not particularly limited as long as it can form the hole injection layer 3. However, a polymer and an electron accepting compound are usually used as the material for the hole injection layer 3. Furthermore, other components may be used as the material for the hole injection layer 3. Hereinafter, materials of these hole injection layers will be described.

(polymer)
The kind of the polymer used as the material for the hole injection layer 3 is arbitrary as long as the effects of the present invention are not significantly impaired. However, among them, a polymer having a hole transporting property (a high molecular weight hole transporting compound, hereinafter referred to as “hole transporting polymer” as appropriate) is preferable. From this viewpoint, ionization of 4.5 eV to 5.5 eV is preferable. A compound having a potential is preferable. The ionization potential is defined as the energy required to emit electrons at the HOMO (highest occupied molecular orbital) level of a material to the vacuum level, and can be measured directly by photoelectron spectroscopy or electrochemically. It can also be obtained by correcting the participation potential obtained with respect to the reference electrode. In the case of the latter method, for example, when a saturated sweet potato electrode (SCE) is used as a reference electrode, it is represented by the following formula ("Molecular Semiconductors", Springer-Verlag, 1985, pp. 98).
Ionization potential = oxidation potential (vs. SCE) + 4.3 eV

  The weight average molecular weight of the hole transporting polymer used as the material of the hole injection layer is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 1000 or more, preferably 2000 or more, more preferably 3000 or more, Usually, it is 500,000 or less, preferably 200,000 or less, more preferably 100,000 or less.

  Examples of the hole transporting polymer include aromatic amine compounds, phthalocyanine derivatives, porphyrin derivatives, oligothiophene derivatives, and the like. Of these, aromatic amine compounds are preferred from the viewpoints of amorphousness, solubility in solvents, and visible light transmittance.

  Of the aromatic amine compounds, aromatic tertiary amine compounds are particularly preferable. In addition, the aromatic tertiary amine compound here is a compound having an aromatic tertiary amine structure, and includes a compound having a group derived from an aromatic tertiary amine. The type of the aromatic tertiary amine compound is not particularly limited, but a polymer compound having a weight average molecular weight of 1,000 or more and 1,000,000 or less is more preferable from the viewpoint of the surface smoothing effect.

  The ratio of the hole transporting polymer in the hole injection layer 3 is arbitrary as long as the effects of the present invention are not significantly impaired, but is usually 10% by weight or more, preferably in terms of the weight percentage with respect to the whole hole injection layer 3. Is 30% by weight or more, usually 99.9% by weight or less, preferably 99% by weight or less. In addition, when using 2 or more types of polymers together, it is preferable that these total content is contained in the said range.

  In addition, only 1 type may be used for a positive hole transport polymer, and it may use 2 or more types together by arbitrary combinations and a ratio.

(Electron-accepting compound)
The kind of the electron-accepting compound used as the material for the hole injection layer 3 is arbitrary as long as the effects of the present invention are not significantly impaired. Examples thereof include onium salts substituted with an organic group such as 4-isopropyl-4′-methyldiphenyliodonium tetrakis (pendafluorophenyl) borate and triphenylsulfonium tetrafluoroborate; No. 251067), high-valence inorganic compounds such as ammonium peroxodisulfate; cyano compounds such as tetracyanoethylene; aromatic boron compounds such as tris (pendafluorophenyl) borane (JP-A-2003-31365); fullerene derivatives ; Iodine etc. are mentioned.

  Of the above compounds, an onium salt substituted with an organic group is preferable in terms of having strong oxidizing power, and an inorganic compound having a high valence is preferable, and an onium salt substituted with an organic group in terms of being soluble in various solvents, A cyano compound and an aromatic boron compound are preferable. Furthermore, an onium salt substituted with an organic group is most preferable from the viewpoint of achieving both strong oxidizing power and high solubility.

  As a material for the hole injection layer 3, any one of the electron-accepting compounds may be used alone, or two or more may be used in any combination and ratio.

  The content of the electron-accepting compound in the hole injection layer 3 and the composition for hole injection layer is arbitrary as long as the effects of the present invention are not significantly impaired. The value relative to the compound is usually 0.1% by weight or more, preferably 1% by weight or more, and usually 100% by weight or less, preferably 60% by weight or less, more preferably 50% by weight or less. A larger amount of the electron-accepting compound is preferable because it is more easily insolubilized, and can be insolubilized in a short time. However, if it is excessively large, the film formability is lowered, and the charge injection / transport property is lowered. There is a fear. In addition, when using together 2 or more types of electron-accepting compounds, it is made for the total content of these to be contained in the said range.

(Low molecular weight hole transport compound)
As a material for the hole injection layer 3, it is preferable to use a low molecular weight hole transporting compound as necessary. The low molecular weight hole transporting compound can be appropriately selected from various compounds conventionally used as a hole injecting / transporting thin film forming material in an organic electroluminescence device. Among them, those having high solvent solubility are preferable.

  Preferable examples of the low molecular weight hole transporting compound include aromatic amine compounds. Of these, aromatic tertiary amine compounds are particularly preferred.

  The molecular weight of the low molecular weight hole transporting compound is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 200 or more, preferably 400 or more, more preferably 600 or more, and usually 5000 or less, preferably Is not more than 3000, more preferably not more than 2000, still more preferably not more than 1700, particularly preferably not more than 1400. If the molecular weight is too small, the heat resistance tends to be low, whereas if the molecular weight of the low molecular weight hole transporting compound is too large, synthesis and purification tend to be difficult.

  In addition, a low molecular weight hole transportable compound may use only 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

(Other ingredients)
As a material for the hole injection layer 3, in addition to the above-described hole transporting polymer, electron accepting compound, and low molecular weight hole transporting compound, in addition to the above-described hole transporting polymer, other components, as long as the effects of the present invention are not significantly impaired. May be included. Examples of other components include various light emitting materials, electron transporting compounds, binders, resins, and coating property improving agents. In addition, only 1 type may be used for another component and it may use 2 or more types together by arbitrary combinations and a ratio.

<Formation of hole injection layer>
When forming the hole injection layer 3 by the wet film-forming method according to the present invention, a coating composition is prepared by dissolving the above-described materials in an appropriate solvent, and using this, a film-forming step, preferably drying is performed. It forms by passing through a storage process through a process. Details of these steps are the same as those described above. In the case where the other organic layer is formed by the wet film forming method according to the present invention, the hole injection layer 3 may be formed by vapor deposition or other methods. Among these, it is preferable to form by the wet film forming method according to the present invention.

  When the hole injection layer 3 is formed by the wet film forming method according to the present invention, the hole injection layer solvent to be contained in the composition for hole injection layer is as long as the hole injection layer 3 can be formed. Any thing can be used. However, at least one of the materials of the hole injection layer 3 such as the above-described hole transporting polymer, electron accepting compound, and low molecular weight hole transporting compound used as necessary, particularly two or more, particularly Is preferably capable of dissolving all materials. Specifically, the hole-transporting polymer is usually 0.005% by weight or more, preferably 0.5% by weight or more, and particularly preferably 1% by weight or more at room temperature and normal pressure. It is preferable to dissolve the functional compound in an amount of usually 0.001% by weight or more, particularly 0.1% by weight or more, and particularly 0.2% by weight or more.

  Suitable examples of the solvent for the hole injection layer are the same as those described for the coating composition. However, aromatic hydrocarbon solvents such as benzene, toluene, and xylene have a low ability to dissolve the electron-accepting compound and the polymer, and are therefore preferably used in a mixture with an ether solvent and an ester solvent.

  The ratio of the hole injection layer solvent to the hole injection layer composition is arbitrary as long as the effects of the present invention are not significantly impaired, but is usually 10% by weight or more, preferably 30% by weight or more, more preferably 50%. It is in the range of not less than weight, usually not more than 99.999% by weight, preferably not more than 99.99% by weight, and more preferably not more than 99.9% by weight. In addition, when mixing and using 2 or more types of solvents as a solvent for positive hole injection layers, it is made for the sum total of these solvents to satisfy | fill this range.

  After the application / film formation of the composition for hole injection layer, the resulting coating film is dried and the solvent for hole injection layer is removed to form a hole injection layer. The method of the wet film forming method is not limited as long as the effect of the present invention is not significantly impaired, and any of the methods described above can be used.

  The thickness of the hole injection layer 3 is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 5 nm or more, preferably 10 nm or more, and usually 1000 nm or less, preferably 500 nm or less.

{Hole transport layer}
In FIG. 2, a hole transport layer 4 is formed on the hole injection layer 3.

  The material for forming the hole transport layer 4 includes two or more tertiary amines typified by 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl. It has a starburst structure such as an aromatic diamine in which a condensed aromatic ring is substituted with a nitrogen atom (Japanese Patent Laid-Open No. 5-234681), 4,4 ′, 4 ″ -tris (1-naphthylphenylamino) triphenylamine, etc. Aromatic amine compounds (J. Lumin., 72-74, 985, 1997), aromatic amine compounds consisting of tetramers of triphenylamine (Chem. Commun., 2175, 1996), 2, Spiro compounds such as 2 ′, 7,7′-tetrakis- (diphenylamino) -9,9′-spirobifluorene (Synth. Metals, 91, 209, 1997) Year)), and carbazole derivatives such as 4,4'-N, N'-dicarbazolebiphenyl. These compounds may be used individually by 1 type, and may be used in mixture of multiple types as needed.

  In addition to the above compounds, polyarylene ether sulfone (Polym. Adv. Tech.) Containing polyvinyl carbazole, polyvinyl triphenylamine (Japanese Patent Laid-Open No. 7-53953), and tetraphenylbenzidine as a material for the hole transport layer 4. 7, Vol. 33, 1996).

The hole transport layer 4 is a layer obtained by polymerizing (crosslinking) a compound having a polymerizable group by irradiation with heat and / or active energy rays (ultraviolet rays, electron beams, infrared rays, microwaves, etc.). Preferably there is.
Here, the “polymerizable group” refers to a group that reacts with the same or different groups of other molecules located nearby by irradiation with heat and / or active energy rays to form a new chemical bond. Although it does not specifically limit as a polymeric group, For example, group containing an unsaturated double bond, cyclic ether, benzocyclobutane etc. is preferable.
Examples of the polymerizable compound include monomers, oligomers, and polymers having the above-described polymerizable group. Among them, monomers are preferable.

Specific examples of the polymerizable compound, for example, triarylamine derivatives, carbazole derivatives, fluorene derivatives, 2,4,6-triphenyl pyridine derivatives, C ₆₀ derivatives, oligothiophene derivatives, phthalocyanine derivatives, porphyrin derivatives, condensed polycyclic An aromatic derivative, a metal complex derivative, etc. are mentioned. Among these, a compound having a partial structure of triphenylamine and a polymerizable group is particularly preferred because of its high electrochemical stability and charge transportability.

The thickness of the hole transport layer 4 is usually 5 nm or more, preferably 10 nm or more, and is usually 300 nm or less, preferably 100 nm or less.
The hole transport layer may be formed by a vacuum deposition method or a wet film formation method. When forming by the wet film-forming method, the coating composition containing the compound used for the said positive hole transport layer and a solvent is prepared, and this composition is formed into a film. After film formation, polymerization (crosslinking) may be performed as described above.

{Light emitting layer}
When the hole injection layer 3 or the hole transport layer 4 is provided, the light emitting layer 5 is provided on the hole transport layer 4. The light emitting layer 5 is a layer that is excited by recombination of holes injected from the anode 2 and electrons injected from the cathode 9 between electrodes to which an electric field is applied, and becomes a main light emitting source.

<Light emitting layer material>
The light emitting layer 5 contains at least a material having a light emitting property (light emitting material) as a constituent material, and preferably a compound having a hole transporting property (hole transporting compound) or an electron transport. A compound (electron transporting compound) having the following properties: There is no particular limitation on the light-emitting material, and a material that emits light at a desired light emission wavelength and has favorable light emission efficiency may be used. Moreover, it is preferable to contain two or more charge transport compounds. Furthermore, the light emitting layer 5 may contain other components as long as the effects of the present invention are not significantly impaired. In addition, when forming the light emitting layer 5 with a wet film-forming method, it is preferable to use a low molecular weight material in any case.

(Luminescent material)
Any known material can be applied as the light emitting material. For example, a fluorescent material or a phosphorescent material may be used, but a phosphorescent material is preferable from the viewpoint of internal quantum efficiency.
For the purpose of improving the solubility in a solvent, it is preferable to reduce the symmetry and rigidity of the molecules of the luminescent material, or to introduce a lipophilic substituent such as an alkyl group.

Hereinafter, although the example of a fluorescent dye is mentioned among light emitting materials, a fluorescent dye is not limited to the following illustrations.
Examples of fluorescent dyes that give blue light emission (blue fluorescent dyes) include naphthalene, perylene, pyrene, anthracene, coumarin, p-bis (2-phenylethenyl) benzene, and derivatives thereof.
Examples of fluorescent dyes that give green light emission (green fluorescent dyes) include quinacridone derivatives, coumarin derivatives, and aluminum complexes such as Al (C ₉ H ₆ NO) ₃ .
Examples of fluorescent dyes that give yellow light (yellow fluorescent dyes) include rubrene and perimidone derivatives.
Examples of fluorescent dyes that give red luminescence (red fluorescent dyes) include DCM (4- (dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) -4H-pyran) compounds, benzopyran derivatives, rhodamine derivatives, benzoates. Examples thereof include thioxanthene derivatives and azabenzothioxanthene.

  As the phosphorescent material, for example, a long-period type periodic table (hereinafter referred to as a long-period type periodic table when referred to as “periodic table” unless otherwise specified) is selected from the seventh to eleventh groups. And an organometallic complex containing a metal.

  Preferred examples of the metal selected from Groups 7 to 11 of the periodic table include ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum, and gold.

  The ligand of the complex is preferably a ligand in which a (hetero) aryl group such as a (hetero) arylpyridine ligand or (hetero) arylpyrazole ligand is linked to pyridine, pyrazole, phenanthroline, etc. A pyridine ligand and a phenylpyrazole ligand are preferable. Here, (hetero) aryl represents an aryl group or a heteroaryl group.

  Specific examples of the phosphorescent material include tris (2-phenylpyridine) iridium, tris (2-phenylpyridine) ruthenium, tris (2-phenylpyridine) palladium, bis (2-phenylpyridine) platinum, tris (2- Phenylpyridine) osmium, tris (2-phenylpyridine) rhenium, octaethyl platinum porphyrin, octaphenyl platinum porphyrin, octaethyl palladium porphyrin, octaphenyl palladium porphyrin, and the like.

  The molecular weight of the compound used as the light emitting material is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 10,000 or less, preferably 5000 or less, more preferably 4000 or less, still more preferably 3000 or less, and usually 100 or more, Preferably it is 200 or more, More preferably, it is 300 or more, More preferably, it is the range of 400 or more. If the molecular weight of the luminescent material is too small, the heat resistance will be significantly reduced, gas generation will be caused, the film quality will be reduced when the film is formed, or the morphology of the organic electroluminescent element will be changed due to migration, etc. Sometimes come. On the other hand, if the molecular weight of the luminescent material is too large, it tends to be difficult to purify the organic compound, or it may take time to dissolve in the solvent.

  In addition, only 1 type may be used for the luminescent material mentioned above, and 2 or more types may be used together by arbitrary combinations and a ratio.

  The ratio of the light emitting material in the light emitting layer 5 is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 0.05% by weight or more, preferably 0.3% by weight or more, more preferably 0.5% by weight or more. In addition, it is usually 35% by weight or less, preferably 25% by weight or less, and more preferably 20% by weight or less. If the amount of the light emitting material is too small, uneven light emission may occur. If the amount is too large, the light emission efficiency may be reduced. In addition, when using together 2 or more types of luminescent material, it is made for the total content of these to be contained in the said range.

(Hole transporting compound)
The light emitting layer 5 may contain a hole transporting compound as a constituent material thereof. Here, among the hole transporting compounds, examples of the low molecular weight hole transporting compound include various compounds exemplified as (low molecular weight hole transporting compound) in the hole injection layer 3 described above. For example, two or more condensed aromatic rings containing two or more tertiary amines represented by 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl are bonded to the nitrogen atom. Aromatic amine compounds having a starburst structure such as substituted aromatic diamines (Japanese Patent Laid-Open No. 5-234681), 4,4 ′, 4 ″ -tris (1-naphthylphenylamino) triphenylamine, etc. (Journal of Luminescence, 1997, Vol.72-74, pp.985), an aromatic amine compound comprising a tetramer of triphenylamine (Chemical Communi). ations, 1996, pp. 2175), spiro compounds such as 2,2 ′, 7,7′-tetrakis- (diphenylamino) -9,9′-spirobifluorene (Synthetic Metals, 1997, Vol. 91, pp. 209) and the like.

  In the light emitting layer 5, only one kind of hole transporting compound may be used, or two or more kinds may be used in any combination and ratio.

  The ratio of the hole transporting compound in the light emitting layer 5 is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 0.1% by weight or more, preferably 0.5% by weight or more, more preferably 1% by weight. In addition, it is usually 95% by weight or less, preferably 65% by weight or less, more preferably 50% by weight or less, and still more preferably 40% by weight or less. If the amount of the hole transporting compound is too small, it may be easily affected by a short circuit, and if it is too large, the film thickness may be uneven. In addition, when using together 2 or more types of hole transportable compounds, it is made for the total content of these to be contained in the said range.

(Electron transporting compound)
The light emitting layer 5 may contain an electron transporting compound as a constituent material thereof. Here, among the electron transporting compounds, examples of low molecular weight electron transporting compounds include 2,5-bis (1-naphthyl) -1,3,4-oxadiazole (BND), 2,5, -Bis (6 '-(2', 2 "-bipyridyl))-1,1-dimethyl-3,4-diphenylsilole (PyPySPyPy), bathophenanthroline (BPhen), 2,9-dimethyl-4,7 -Diphenyl-1,10-phenanthroline (BCP, bathocuproin), 2- (4-biphenylyl) -5- (p-tertiarybutylphenyl) -1,3,4-oxadiazole (tBu-PBD), 4 , 4′-bis (9-carbazole) -biphenyl (CBP), etc. In the light emitting layer 5, only one type of electron transporting compound may be used, or two or more types may be combined arbitrarily. It may be used in combination with so and proportions.

  The proportion of the electron transporting compound in the light emitting layer 5 is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 0.1% by weight or more, preferably 0.5% by weight or more, more preferably 1% by weight or more. Also, it is usually 95% by weight or less, preferably 65% by weight or less, more preferably 50% by weight or less, and still more preferably 40% by weight or less. If the amount of the electron transporting compound is too small, it may be easily affected by a short circuit, and if it is too large, the film thickness may be uneven. In addition, when using together 2 or more types of electron transport compounds, it is made for the total content of these to be contained in the said range.

<Formation of light emitting layer>
When forming the light emitting layer 5 by the wet film-forming method according to the present invention, a coating composition is prepared by dissolving the above-described materials in an appropriate solvent, and a film-forming step, preferably a drying step, is used using the composition. Through a storage step. Details of these steps are the same as those described above. In addition, when forming another organic layer with the wet film-forming method based on this invention, you may use a vapor deposition method or another method for formation of the light emitting layer 5. FIG.

  As the light emitting layer solvent to be contained in the coating composition for forming the light emitting layer 5 by the wet film forming method according to the present invention, any solvent can be used as long as the light emitting layer can be formed. However, those capable of dissolving the light-emitting material, the hole transporting compound, and the electron transporting compound are preferable. Specifically, the solubility of the light-emitting material, the hole transporting compound or the electron transporting compound is usually 0.01% by weight or more, particularly 0.05% by weight or more, particularly 0.1% at room temperature and normal pressure. It is preferable to dissolve by weight% or more.

  The suitable example of the solvent for light emitting layers is the same as the solvent demonstrated by the said composition for application | coating.

  The ratio of the solvent for the light emitting layer to the coating composition for forming the light emitting layer 5 is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 0.01% by weight or more, preferably 0.1% by weight. Above, more preferably 0.5% by weight or more, and usually 70% by weight or less, preferably 60% by weight or less, more preferably 50% by weight or less. In addition, when mixing and using 2 or more types of solvents as a solvent for light emitting layers, it is made for the sum total of these solvents to satisfy | fill this range.

  After application / film formation of the coating composition for producing the light emitting layer, the obtained coating film is dried and the light emitting layer solvent is removed to form the light emitting layer. The method of the wet film forming method is not limited as long as the effect of the present invention is not significantly impaired, and any of the methods described above can be used.

  The thickness of the light emitting layer 5 is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 3 nm or more, preferably 5 nm or more, and usually 200 nm or less, preferably 100 nm or less. If the thickness of the light emitting layer 5 is too thin, defects may occur in the film, and if it is too thick, the driving voltage may increase.

{Hole blocking layer}
A hole blocking layer 6 may be provided between the light emitting layer 5 and an electron injection layer 8 described later. The hole blocking layer 6 is a layer laminated on the light emitting layer 5 so as to be in contact with the interface of the light emitting layer 5 on the cathode 9 side.

  The hole blocking layer 6 has a role of blocking holes moving from the anode 2 from reaching the cathode 9 and a role of efficiently transporting electrons injected from the cathode 9 toward the light emitting layer 5. Have

  The physical properties required for the material constituting the hole blocking layer 6 include high electron mobility, low hole mobility, a large energy gap (difference between HOMO and LUMO), and excited triplet level (T1). Is high. Examples of the material for the hole blocking layer satisfying such conditions include bis (2-methyl-8-quinolinolato) (phenolato) aluminum, bis (2-methyl-8-quinolinolato) (triphenylsilanolato) aluminum, and the like. Mixed metal complexes such as bis (2-methyl-8-quinolato) aluminum-μ-oxo-bis- (2-methyl-8-quinolinato) aluminum binuclear metal complexes, distyrylbiphenyl derivatives, etc. Triazole derivatives such as styryl compounds (JP-A-11-242996), 3- (4-biphenylyl) -4-phenyl-5 (4-tert-butylphenyl) -1,2,4-triazole (JP-A-7 -41759), phenanthroline derivatives such as bathocuproine (JP-A-10-79297), and the like. That. Further, a compound having at least one pyridine ring substituted at positions 2, 4, and 6 described in International Publication No. 2005-022962 is also preferable as a material for the hole blocking layer 6.

  In addition, the material of the hole-blocking layer 6 may use only 1 type, and may use 2 or more types together by arbitrary combinations and ratios.

  There is no restriction | limiting in the formation method of the hole-blocking layer 6. FIG. Therefore, it can be formed by a wet film forming method, a vapor deposition method, or other methods.

  The thickness of the hole blocking layer 6 is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 0.3 nm or more, preferably 0.5 nm or more, and usually 100 nm or less, preferably 50 nm or less.

{Electron transport layer}
An electron transport layer 7 may be provided between the light emitting layer 5 and an electron injection layer 8 described later.
The electron transport layer 7 is provided for the purpose of further improving the light emission efficiency of the device, and efficiently transports electrons injected from the cathode 9 between the electrodes to which an electric field is applied in the direction of the light emitting layer 5. Formed from a compound capable of

  As an electron transport compound used for the electron transport layer 7, usually, the electron injection efficiency from the cathode 9 or the electron injection layer 8 is high, and the injected electrons are transported efficiently with high electron mobility. The compound which can be used is used. Examples of the compound satisfying such conditions include metal complexes such as aluminum complexes of 8-hydroxyquinoline (Japanese Patent Laid-Open No. 59-194393), metal complexes of 10-hydroxybenzo [h] quinoline, oxadiazole derivatives , Distyrylbiphenyl derivatives, silole derivatives, 3-hydroxyflavone metal complexes, 5-hydroxyflavone metal complexes, benzoxazole metal complexes, benzothiazole metal complexes, trisbenzimidazolylbenzene (US Pat. No. 5,645,948), quinoxaline compounds ( JP-A-6-207169), phenanthroline derivative (JP-A-5-331459), 2-t-butyl-9,10-N, N'-dicyanoanthraquinonediimine, n-type hydrogenated amorphous silicon carbide , N-type zinc sulfide, n-type zinc Such as emissions of zinc, and the like.

  In addition, the material of the electron carrying layer 7 may use only 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  There is no restriction | limiting in the formation method of the electron carrying layer 7. FIG. Therefore, it can be formed by a wet film forming method, a vapor deposition method, or other methods.

  The thickness of the electron transport layer 7 is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 1 nm or more, preferably 5 nm or more, and usually 300 nm or less, preferably 100 nm or less.

{Electron injection layer}
The electron injection layer 8 plays a role of efficiently injecting electrons injected from the cathode 9 into the light emitting layer 5. In order to perform electron injection efficiently, the material for forming the electron injection layer 8 is preferably a metal having a low work function. Examples include alkali metals such as sodium and cesium, alkaline earth metals such as barium and calcium, and the film thickness is preferably from 0.1 nm to 5 nm.

  Furthermore, an organic electron transport compound represented by a metal complex such as a nitrogen-containing heterocyclic compound such as bathophenanthroline or an aluminum complex of 8-hydroxyquinoline is doped with an alkali metal such as sodium, potassium, cesium, lithium or rubidium ( (As described in JP-A-10-270171, JP-A-2002-1000047, JP-A-2002-1000048, etc.), it is possible to improve the electron injection / transport properties and achieve excellent film quality. preferable. In this case, the film thickness is usually 5 nm or more, preferably 10 nm or more, and is usually 200 nm or less, preferably 100 nm or less.

  In addition, the material of the electron injection layer 8 may use only 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  There is no restriction | limiting in the formation method of the electron injection layer 8. FIG. Therefore, it can be formed by a wet film forming method, a vapor deposition method, or other methods.

{cathode}
The cathode 9 plays a role of injecting electrons into a layer (such as the electron injection layer 8 or the light emitting layer 5) on the light emitting layer 5 side.

  As the material of the cathode 9, the material used for the anode 2 can be used. However, in order to perform electron injection efficiently, a metal having a low work function is preferable. For example, tin, magnesium, indium, A suitable metal such as calcium, aluminum, silver, or an alloy thereof is used. Specific examples include low work function alloy electrodes such as magnesium-silver alloy, magnesium-indium alloy, and aluminum-lithium alloy.

  In addition, the material of the cathode 9 may use only 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  The film thickness of the cathode 9 is usually the same as that of the anode 2.

  Further, for the purpose of protecting the cathode 9 made of a low work function metal, it is preferable to further stack a metal layer having a high work function and stable to the atmosphere because the stability of the device is increased. For this purpose, for example, metals such as aluminum, silver, copper, nickel, chromium, gold and platinum are used. In addition, these materials may be used only by 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

{Other layers}
The organic electroluminescent element according to the present invention may have another configuration without departing from the gist thereof. For example, as long as the performance is not impaired, an arbitrary layer may be provided between the anode 2 and the cathode 9 in addition to the layers described above, and an arbitrary layer may be omitted. . For example, as shown in FIG. 3, the organic electroluminescent element produced in the Example mentioned later has the hole blocking layer 6 and the electron transport layer 7 omitted from the organic electroluminescent element of FIG.

<Electron blocking layer>
Examples of the layer that may be included include an electron blocking layer.
The electron blocking layer is provided between the hole injection layer 3 or the hole transport layer 4 and the light emitting layer 5 and prevents electrons moving from the light emitting layer 5 from reaching the hole injection layer 3. Thus, the probability of recombination of holes and electrons in the light emitting layer 5 is increased, the excitons generated are confined in the light emitting layer 5, and the holes injected from the hole injection layer 3 are efficiently collected. There is a role to transport in the direction of. In particular, when a phosphorescent material or a blue light emitting material is used as the light emitting material, it is effective to provide an electron blocking layer.

  The characteristics required for the electron blocking layer include high hole transportability, a large energy gap (difference between HOMO and LUMO), and a high excited triplet level (T1). Furthermore, in the present invention, when the light emitting layer 5 is formed as an organic layer according to the present invention by a wet film formation method, the electron blocking layer is also required to be compatible with the wet film formation. Examples of the material used for such an electron blocking layer include a copolymer of dioctylfluorene and triphenylamine typified by F8-TFB (described in International Publication No. 2004/084260).

  In addition, the material of an electron blocking layer may use only 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  There is no restriction | limiting in the formation method of an electron blocking layer. Therefore, it can be formed by a wet film forming method, a vapor deposition method, or other methods.

Further, at the interface between the cathode 9 and the light emitting layer 5 or the electron transport layer 7, for example, lithium fluoride (LiF), magnesium fluoride (MgF ₂ ), lithium oxide (Li ₂ O), cesium carbonate (II) (CsCO ₃ ). Inserting an ultrathin insulating film (0.1 to 5 nm) formed by the above method is also an effective method for improving the efficiency of the device (Applied Physics Letters, 1997, Vol. 70, pp. 152; (Kaihei 10-74586; IEEE Transactions on Electron Devices, 1997, Vol. 44, pp. 1245; SID 04 Digest, pp. 154, etc.).

  Moreover, in the layer structure demonstrated above, it is also possible to laminate | stack components other than a board | substrate in reverse order. For example, in the case of the layer configuration of FIG. 1, the other components on the substrate 1 are the cathode 9, the electron injection layer 8, the electron transport layer 7, the hole blocking layer 6, the light emitting layer 5, the hole transport layer 4, the positive layer. The hole injection layer 3 and the anode 2 may be provided in this order.

  Furthermore, it is also possible to constitute the organic electroluminescent element according to the present invention by laminating components other than the substrate between two substrates, at least one of which is transparent.

In addition, a structure in which a plurality of components (light emitting units) other than the substrate are stacked in a plurality of layers (a structure in which a plurality of light emitting units are stacked) may be employed. In that case, instead of the interface layer between the steps (between the light emitting units) (when the anode is ITO and the cathode is Al, these two layers), for example, a charge made of vanadium pentoxide (V ₂ O ₅ ) or the like. When a generation layer (Carrier Generation Layer: CGL) is provided, a barrier between steps is reduced, which is more preferable from the viewpoint of light emission efficiency and driving voltage.

  Furthermore, the organic electroluminescent device according to the present invention may be configured as a single organic electroluminescent device, or may be applied to a configuration in which a plurality of organic electroluminescent devices are arranged in an array. You may apply to the structure by which the cathode is arrange | positioned at XY matrix form.

  Each layer described above may contain components other than those described as materials unless the effects of the present invention are significantly impaired.

[Organic EL display]
The organic EL display of the present invention uses an organic electroluminescent element produced by the method for producing an organic electroluminescent element of the present invention as described above. There is no restriction | limiting in particular about the model and structure of the organic electroluminescent display of this invention, It can assemble in accordance with a conventional method using the organic electroluminescent element manufactured by the manufacturing method of the organic electroluminescent element of this invention.
For example, the organic EL display of the present invention is formed by a method as described in “Organic EL Display” (Ohm, published on August 20, 2004, Shizushi Tokito, Chiba Adachi, Hideyuki Murata). can do.

[Organic EL lighting]
The organic EL lighting of the present invention uses an organic electroluminescent element manufactured by the above-described method for manufacturing an organic electroluminescent element of the present invention. There is no restriction | limiting in particular about the type and structure of the organic electroluminescent illumination of this invention, It can assemble in accordance with a conventional method using the organic electroluminescent element manufactured by the manufacturing method of the organic electroluminescent element of this invention.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the description of the following examples unless it exceeds the gist.

[Example 1]
The organic electroluminescent element shown in FIG. 3 was produced.
An indium tin oxide (ITO) transparent conductive film deposited on a glass substrate 1 with a thickness of 120 nm (manufactured by Sanyo Vacuum Co., Ltd., sputtered film product) using ordinary photolithography technology and hydrochloric acid etching Then, the anode 2 was formed by patterning into stripes having a width of 2 mm. The patterned ITO substrate is cleaned in the order of ultrasonic cleaning with an aqueous surfactant solution, water cleaning with ultrapure water, ultrasonic cleaning with ultrapure water, and water cleaning with ultrapure water, followed by drying with compressed air, and finally UV irradiation. Ozone cleaning was performed.

Next, the hole injection layer 3 was formed through the wet film-forming process, the drying process, and the storage process according to the present invention.
First, 2 wt% of a hole transporting polymer (weight average molecular weight 29400) having a repeating structure represented by the following structural formula (P1) and 4-isopropyl-4′-methyldiphenyliodonium tetrakis ( Pentafluorophenyl) borate 0.8% by weight was dissolved in ethyl benzoate as a solvent, and then filtered using a PTFE (polytetrafluoroethylene) membrane filter having a pore size of 0.2 μm to prepare a coating composition. did. This coating composition was spin-coated on the glass substrate on which the anode 2 was formed to form a film (film formation process). The spin coating was performed in an air atmosphere at a temperature of 23 ° C. and a relative humidity of 60%, the spinner rotation speed was 1500 rpm, and the spinner time was 30 seconds.

After spin coating, it was heated and dried at 80 ° C. for 1 minute on a hot plate, and then heated at 230 ° C. for 180 minutes in a normal pressure air atmosphere in a heating furnace (drying step).
The film thickness after drying was 30 nm.

  As shown in FIG. 1, the substrate on which the hole injection layer 3 is formed is set to 75 ° in the atmosphere using a substrate support, and the angle (horizontal crossing angle θ) between the upper surface of the hole injection layer and the horizontal plane is 75 °. And kept for 96 hours at a temperature of 23 ° C. and a relative humidity of 50% (storage process).

Next, the substrate on which the hole injection layer 3 is formed is placed in a vacuum deposition apparatus, and the aromatic amine compound represented by the following structural formula (H-1) is placed in a ceramic crucible disposed in the apparatus. 4,4′-bis [N- (9-phenanthryl) -N-phenylamino] biphenyl was heated for vapor deposition. The degree of vacuum during deposition is 1.7 × 10 ⁻⁶ Pa, the deposition rate is 0.08 to 0.12 nm / second, and a 45 nm-thick film is laminated on the hole injection layer 3 to form a hole transport layer. 4 was formed.

Subsequently, as a material for the light-emitting layer 5, an aluminum 8-hydroxyquinoline complex (Al (C ₉ H ₆ NO) ₃ ) represented by the following structural formula (E-1) was deposited. The degree of vacuum during vapor deposition is 1.3 × 10 ⁻⁶ Pa, the vapor deposition rate is 0.08 to 0.12 nm / second, and a light emitting layer 5 is formed by laminating a film with a thickness of 60 nm on the hole transport layer 4. Formed.

Here, the element that has been vapor-deposited up to the light emitting layer 5 is once taken out from the vacuum vapor deposition apparatus into the atmosphere, and a 2 mm wide stripe shadow mask is orthogonal to the ITO stripe of the anode 2 as a mask for cathode vapor deposition. As in the case of the organic layer deposition, the device was placed in a separate vacuum deposition apparatus and exhausted until the degree of vacuum in the apparatus became 1.0 × 10 ⁻⁴ Pa or less.

First, lithium fluoride (LiF) was controlled as the electron injection layer 8 at a deposition rate of 0.01 to 0.015 nm / second and a degree of vacuum of 2.3 to 6.7 × 10 ⁻⁵ Pa using a molybdenum boat. The film was formed on the light emitting layer 5 with a film thickness of 0.5 nm.

Next, aluminum as a cathode 9 is similarly heated by a molybdenum boat and controlled at a deposition rate of 0.09 to 0.5 nm / second and a degree of vacuum of 2.5 to 15 × 10 ⁻⁵ Pa, and an aluminum film with a thickness of 80 nm. A layer was formed.

  The substrate temperature at the time of vapor deposition of the electron injection layer 8 and the cathode 9 was kept at room temperature.

Subsequently, in order to prevent the element from being deteriorated by moisture in the atmosphere during storage, a sealing process was performed by the method described below.
In a nitrogen glove box, a photocurable resin (30Y-437 manufactured by ThreeBond Co., Ltd.) with a width of about 1 mm is applied to the outer periphery of a 23 mm × 23 mm glass plate, and a moisture getter sheet (Dynic Corporation) is applied to the center. Made). On this, the board | substrate which complete | finished cathode formation was bonded together so that the vapor-deposited surface might oppose a desiccant sheet. Then, only the area | region where the photocurable resin was apply | coated was irradiated with ultraviolet light, and resin was hardened.

  As described above, an organic electroluminescent element having a light emitting area portion having a size of 2 mm × 2 mm was obtained.

The obtained organic electroluminescent element was continuously energized with a constant DC current for 50 hours at room temperature at a current density at the start of energization of 50 mA / cm ² . As a result of the energization test, the presence or absence of a short circuit was confirmed, and the ratio of the number of shorted elements (= (number of shorted elements / number of energized test elements) × 100) was calculated. The results are shown in Table 1.

[Example 2]
As a result of producing an organic electroluminescence device in the same manner as in Example 1 except that in the storage step after forming the hole injection layer, in nitrogen instead of in the air, an organic electroluminescence device was produced and the current test was conducted in the same manner. Is shown in Table 1.

[Comparative Example 1]
An organic electroluminescent device was prepared in the same manner as in Example 1 except that the horizontal crossing angle θ was set to 165 ° (that is, the film formation surface was facing upward) in the storage step after the formation of the hole injection layer, and the energization was similarly performed. The test results are shown in Table 1.

[Comparative Example 2]
In the storage process after the hole injection layer was formed, an organic electroluminescence device was prepared in the same manner as in Example 2 except that the horizontal crossing angle θ was set to 165 °. did.

[Example 3]
The organic electroluminescent element shown in FIG. 4 was produced.
An ITO substrate having an anode 2 formed on a glass substrate 1 was produced in the same manner as in Example 1 except that an indium tin oxide (ITO) transparent conductive film was deposited to a thickness of 150 nm.

  Next, 2% by weight of a hole transporting polymer (weight average molecular weight 29400) having a repeating structure represented by the structural formula (P1) and 4-isopropyl-4′-methyldiphenyliodonium tetrakis represented by the structural formula (A1) A coating composition was prepared by dissolving 0.8% by weight of (pentafluorophenyl) borate in ethyl benzoate as a solvent. This coating composition was spin-coated on the glass substrate on which the anode 2 was formed to form a film. The spin coating was performed in two stages: a spinner rotation speed of 500 rpm and a spinner time of 2 seconds, and then a spinner rotation speed of 1500 rpm and a spinner time of 30 seconds. After spin coating, the film was heated and dried at 230 ° C. for 180 minutes to form a hole injection layer 3 having a dried film thickness of 30 nm.

  Next, the light emitting layer 5 was formed through the wet film-forming process, the drying process, and the storage process according to the present invention.

  As a material of the light emitting layer 5, the compounds represented by the following formula (2), the following formula (3), and the following formula (4) are respectively added to 1.5 wt%, 1.5 wt%, and 0.15 wt%. Thus, it was dissolved in dehydrated xylene as a solvent to prepare a coating composition for forming a light emitting layer.

  Using this coating composition, a film was formed on the hole injection layer 3 by spin coating in an environment having a temperature of 23 ° C., a relative humidity of 56%, and an oxygen volume concentration of 21% (film formation step). The spin coating was performed under the two-stage conditions of a spinner rotation speed of 500 rpm for 2 seconds and then 1300 rpm for 30 seconds.

Then, it heat-dried under 130 degreeC pressure reduction (1 * 10 < ^-1 > Pa) for 1 hour (drying process). A hot plate (Bellger type vacuum oven BV-001, manufactured by Shibata Kagaku Co., Ltd.) was used as the heating means. The distance between the heating means and the film formation surface was 0.1 cm.
Further, the heat-dried thin film was cooled to room temperature under reduced pressure (1 × 10 ⁻¹ Pa) to obtain a uniform light-emitting layer 5 having a thickness of 80 nm.

  As shown in FIG. 1, the substrate on which the light emitting layer 5 is formed is maintained at a temperature of 0 ° (horizontal crossing angle θ) between the upper surface of the light emitting layer and the horizontal plane as shown in FIG. Storage was performed for 60 minutes in an environment of 23 ° C., relative humidity of 56%, and oxygen volume concentration of 21% (storage process).

Next, the substrate on which the light emitting layer 5 was formed was placed in a vacuum vapor deposition apparatus, and a compound represented by the following formula (5) was put into a ceramic crucible disposed in the apparatus for vapor deposition. The degree of vacuum during deposition is about 2.2 × 10 ⁻⁴ Pa, the crucible temperature is 265 to 270 ° C., the deposition rate is 0.08 to 0.12 nm / second, and a film with a thickness of 5 nm is formed on the light emitting layer 5. The hole blocking layer 6 was formed by stacking.

Next, an aluminum 8-hydroxyquinoline complex (Al (C ₉ H ₆ NO) ₃ ) represented by the structural formula (E-1) is similarly deposited on the hole blocking layer 6 to form an electron transport layer 7. Formed. At this time, the crucible temperature of the aluminum 8-hydroxyquinoline complex is controlled in the range of 360 to 400 ° C., the degree of vacuum during the deposition is about 1.4 × 10 ⁻⁴ Pa, and the deposition rate is 0.08 to 0.12 nm. The film thickness was 30 nm per second.

  The substrate temperature during vacuum deposition of the hole blocking layer 6 and the electron transport layer 7 was kept at room temperature.

Here, the element which performed vapor deposition to the electron carrying layer 7 was once taken out in the air from the inside of the said vacuum vapor deposition apparatus. A 2 mm wide stripe-shaped shadow mask was brought into close contact with the element so as to be orthogonal to the ITO stripe of the anode 2 as a mask for cathode vapor deposition. It was installed in another vacuum deposition apparatus and evacuated until the degree of vacuum in the apparatus was about 2.5 × 10 ⁻⁴ Pa or less.

Next, lithium fluoride (LiF) is deposited on the electron transport layer 7 as an electron injection layer 8 by using a molybdenum boat, a deposition rate of 0.01 nm / second, and a degree of vacuum of about 2.6 × 10 ⁻⁴ Pa. Thus, a film having a thickness of 0.5 nm was formed.

Next, on the electron injection layer 8, aluminum is heated as a cathode 9 by a molybdenum boat, and deposited at a deposition rate of 0.1 to 0.4 nm / second and a degree of vacuum of about 3.0 × 10 ⁻⁴ Pa. Then, an aluminum layer having a thickness of 80 nm was formed to complete the cathode 9.

  The substrate temperature at the time of vapor deposition of the electron injection layer 8 and the cathode 9 was kept at room temperature.

  Finally, glass sealing was performed to obtain an organic electroluminescent element having a light emitting area portion having a size of 2 mm × 2 mm.

  About the obtained organic electroluminescent element, it carried out similarly to Example 1, the energization test by DC constant current continuous energization was performed, the presence or absence of the short circuit was confirmed, and the ratio of the number of the short-circuited element was computed. As a result, the proportion of shorted elements was as low as 8.3%.

[Example 4]
In Example 3, in the step of storing the light emitting layer 5, instead of storing for 60 minutes in an environment of a temperature of 23 ° C., a relative humidity of 56%, and an oxygen volume concentration of 21%, a temperature of 23 ° C. and a degree of vacuum of about 2. An organic electroluminescent element was produced in the same manner as in Example 3 except that it was stored at 6 × 10 ⁻⁴ Pa for 12 hours.
About the obtained organic electroluminescent element, when it carried out similarly to Example 1 and the energization test was done and the ratio of the number of the short-circuited element was computed, the ratio of the short-circuited element was as low as 12.5%.

  From the above results, it is apparent that a long-life device with few short circuits can be obtained by adjusting the horizontal crossing angle θ during storage after wet film formation according to the present invention.

DESCRIPTION OF SYMBOLS 1 Substrate 2 Anode 3 Hole injection layer 4 Hole transport layer 5 Light emitting layer 6 Hole blocking layer 7 Electron transport layer 8 Electron injection layer 9 Cathode 11 Substrate 12 Organic layer 12A Top surface of organic layer

Claims (5)

In a method for producing an organic electroluminescent element having an organic layer formed by a wet film forming method of at least one layer between two electrodes,
A film forming step of forming the organic layer by a wet film forming method, and a storage step of storing the film after forming the film,
In the storage step, when the angle θ between the upper surface of the organic layer and the horizontal plane when the upper surface of the formed organic layer faces downward parallel to the horizontal plane is 0 °, the upper surface of the organic layer and the horizontal plane A method for producing an organic electroluminescent element, characterized by being a step of storing at an angle θ of 0 ° to 100 °.   2. The method for manufacturing an organic electroluminescent element according to claim 1, wherein the organic layer formed by the wet film forming method is an organic layer formed on the electrode.   The method for producing an organic electroluminescent element according to claim 1, wherein the organic electroluminescent element is stored using a substrate support.   The organic electroluminescent display using the organic electroluminescent element manufactured by the manufacturing method of the organic electroluminescent element as described in any one of Claims 1 thru | or 3.   Organic EL lighting using the organic electroluminescent element manufactured by the manufacturing method of the organic electroluminescent element as described in any one of Claims 1 thru | or 3.

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