JP2001189193A - Light emission element and method of manufacturing the same, and display device and lighting device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light emission element and a method of manufacturing the same which can realize a high luminous efficiency with easy patterning. SOLUTION: This light emission element 10 comprises an anode 2 formed on a substrate 1, a cathode 4 disposed oppositely to the anode 2, and a luminous region 3 disposed between the anode 2 and the cathode 4. The luminous region 3 contains polymer 3A, luminescent molecules 3G contributing to the light emission, and a charge carrying material 3F. There is a concentration distribution of the luminescent molecules 3G and the charge carrying material 3F in the thickness direction (from the anode 2 toward the cathode 4) of the luminous region 3. That is, in the luminous region 3, the concentration of the luminescent molecules 3G and the charge carrying material 3F nearer to the cathode 4 is higher and the concentration nearer to the anode 2 is lower. Such organic luminous device can realize high luminous efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device used as a flat light source or a flat display.

[0002]

2. Description of the Related Art Electroluminescent devices are self-luminous, have high visibility, are excellent in display performance, can respond at high speed, and can be made thin. Are gathering.

[0003] Among them, organic E using an organic compound as a luminous body
The L element has features such as being able to be driven at a lower voltage, being easy to increase in area, and being able to easily obtain a desired luminescent color by selecting an appropriate dye, as compared with the inorganic EL element. It is being actively developed as a next-generation display.

As an EL element using an organic luminous body, blue light emission is obtained by applying a voltage of 30 V to an anthracene vapor-deposited film having a thickness of 1 μm or less (Thi.
n Solid Films, 94 (1982) 171). However, since sufficient luminance cannot be obtained even when a high voltage is applied to this element, it was necessary to further improve the luminous efficiency.

On the other hand, Tang et al. Laminated a transparent electrode (anode), a hole transporting layer, an electron transporting light emitting region, and a cathode using a metal having a low work function to reduce the voltage and improve the luminous efficiency. With an applied voltage of 10 V or less, a luminance of 1000 cd / m ² was realized (Appl. Phys.
tt. 51 (1987) 913). In addition, Tris (8
-Quinolinolato) aluminum complex (hereinafter referred to as “Al
q "). Alq is an excellent luminescent substance having both high luminous efficiency and electron transport performance.

Further, a device having a three-layer structure in which a light emitting region is sandwiched between a hole transport layer and an electron transport layer (Jpn. J. Appl Phys.,
27 (1988) L269) and an element (J. Appl. Phys., 65 (1989) 3610) which obtains light emission from a dye doped in the light emitting region (a coumarin derivative or a fluorescent dye such as DCM1 in Alq). ing. In the above report, it was found that the luminescent color was changed by appropriate selection of the dye, and it was also clarified that the luminous efficiency was increased as compared with the undoped one.

On the other hand, while all the layers of the element having the above-described structure are formed by a dry process such as a vacuum evaporation method,
There is a method of forming an element by a so-called wet film forming method such as a spin coating method or a casting method (JP-A-3-790, JP-A-3-171590).

That is, at least one of the materials for forming the hole transport layer, the electron transport layer, and the light emitting region is dissolved in a suitable solvent together with a polymer binder, and the solution is applied to the electrode surface to form a light emitting region. Thereafter, an electrode is further formed on the light emitting region by a vapor deposition method or the like. Hereinafter, the organic light-emitting device thus manufactured is referred to as a polymer-dispersed light-emitting device with respect to a conventional stacked light-emitting device.

Advantages of the polymer-dispersed light-emitting device as compared with an organic light-emitting device manufactured by a dry process include the following. (1) Materials that are difficult to form in a dry process such as vapor deposition can be used. (2) A small amount of doping, which is difficult to control in a dry process, can be easily realized. (3) It is easy to increase the area. (4) It can be manufactured at low cost. (5) By introducing a plurality of light emitting molecules, light emission from each light emitting molecule can be easily obtained simultaneously (white light emission is possible). (6) In the conventional stacked light emitting device, each layer is in an amorphous state, whereas in the polymer dispersed light emitting device, each material is dispersed in a polymer binder, so that it is thermally stable.

The structure of the light emitting region of a conventional polymer dispersed light emitting device is a dispersion of a perinone derivative or tris (8-quinolinolato) aluminum as a light emitting molecule in polyvinyl carbazole, and a light emitting molecule of tris (8-quinolinolato) in polycarbonate. Dispersion of aluminum and tetraphenylbenzidine, etc. (JP-A-3-790, JP-A-3-17159)
No. 0).

[0011]

(First Problem) The polymer-dispersed light-emitting device has the above-mentioned advantages, but has a problem that the luminous efficiency is lower than that of the conventional laminated light-emitting device.

That is, in the stacked light emitting device, holes are injected from the anode into the hole transport layer, and electrons are injected from the cathode into the electron transporting light emitting region or the electron transport layer. Then, when these holes and electrons recombine in the light emitting region, excitons are formed, and the excitons emit light when they transition to the ground state. Here, since electron transport and hole transport are functionally separated, recombination of electrons and holes occurs only near the interface between the layers. Therefore, exciton generation occurs efficiently, and luminous efficiency also improves.

Further, regarding the injection of holes and electrons, if the material of the layer in contact with each electrode is selected so as to reduce the injection barrier between the anode and the cathode, the injection can be easily performed and the driving at a low voltage is possible. Becomes

On the other hand, in the case of the polymer-dispersed light-emitting device, since it mainly has a single-layer structure, a device in which recombination of holes and electrons and generation of excitons occur locally as in the stacked light-emitting device described above does not occur. No hole from the electrode
Since the electron injection barrier is large, it has been difficult to improve the luminous efficiency.

As described above, since the light-emitting sites are dispersed throughout the light-emitting region, it is difficult to balance the injection and transport of holes and electrons, and as a result, the recombination probability is reduced and sufficient light-emitting efficiency cannot be obtained. . Therefore, as a means for increasing the efficiency, the recombination region of holes and electrons is concentrated in a specific region.

As described above, a method of laminating layers with separated functions is effective. However, in a polymer system to be formed by coating, the solvent contained in the polymer solution of the second layer to be laminated on top is formed by a solvent. A solvent must be chosen that does not dissolve the filmed first layer.

As the number of laminated films increases, it becomes necessary to select a solvent and to select a material soluble in the selected solvent. As a result, there is a problem that the range of material selection is further narrowed, and effective high efficiency cannot be realized.

(Second Problem) Another problem of the polymer-dispersed light-emitting device is that patterning (color separation) is difficult when a color panel is manufactured. That is, when a color panel is manufactured by a dry process such as a vacuum evaporation method, an element of each color can be formed at a desired position by installing an evaporation mask on a substrate. In a wet film forming method such as a method, a light emitting region is formed on the entire surface of the substrate,
The above patterning cannot be performed.

On the other hand, patterning by an ink jet method has been proposed (for example, Japanese Patent Application Laid-Open No. 10-1).
2377). This is to form a desired pattern by discharging a material of a light emitting region containing a polymer or a precursor of the polymer from a nozzle by an ink jet method.

However, in the conventional patterning by the ink jet method, the viscosity of the polymer solution or the like to be applied is large, so that the nozzle of the ink head is clogged, and it is difficult to form a fine pattern.

The present invention solves the above-mentioned problems, and provides an organic light-emitting device which can achieve high luminous efficiency and can be easily patterned at the same time even in a polymer-dispersed organic light-emitting device, and a method of manufacturing the same. is there.

[0022]

SUMMARY OF THE INVENTION A group of the present invention has been made in view of the above situation, and an object of the present invention is to provide a light emitting device having high luminous efficiency.

It should be noted that the group of the present invention is based on the same or similar ideas. However, since each invention is embodied by a different embodiment, in this specification, these one group of the present invention will be referred to as a first invention group and a second invention group for each closely related invention. Classify as In the following, the content of each section (group of invention) will be sequentially described.

(First Invention Group) The inventors of the present invention have made intensive studies to achieve the above object. As a result, when manufacturing a polymer-dispersed light-emitting device, first, a polymer film was formed and then formed. It has been found that, by infiltrating a luminescent molecule or a luminescent molecule and a charge transport material, patterning can be easily performed while obtaining high luminous efficiency.

Specifically, the invention of claim 1 is a light-emitting element having a light-emitting region between an anode and a cathode, wherein the light-emitting region has a substance contributing to light emission and a material for containing the substance. The substance that contributes to the light emission is composed of a medium and has a concentration distribution substantially continuously from the anode side to the cathode side of the light emitting region.

According to a second aspect of the present invention, in the light emitting device according to the first aspect, the substance contributing to the light emission is such that one of the anode side and the cathode side of the light emitting region is the other. The density distribution is such that the density is higher than the side, and the density is continuously reduced from the one side to the other side.

[0027] With the above structure, the hole injected from the anode into the light emitting region and the electron injected from the cathode into the light emitting region are formed in a portion of the light emitting region where the substance contributing to light emission is highly concentrated. Rejoin. In this way, the recombination region between the holes and the electrons can be concentrated, so that the recombination efficiency between the electrons and the holes increases, and the luminous efficiency can be improved.

The term "substance contributing to light emission" refers to, for example, an organic binder, a charge transporting material and a dimer as well as a light-emitting molecule that emits light by injecting a charge as described in the embodiment described later. , An excimer or a substance capable of emitting light from these by forming an exciplex. Here, the dimer means a substance bonded to the organic binder or the charge transporting material in a ground state, and the excimer or the exciplex means the organic binder or the exciplex in a state where a charge is injected and excited. It means those that have reacted with the charge transporting material.

According to a third aspect of the present invention, in the light emitting device according to the first or second aspect, the light emitting region is
Further, it is characterized in that it contains a charge transporting substance.

With the above configuration, the charge transporting property of the light emitting region can be further improved, and the efficiency of recombination between electrons and holes can be improved.

According to a fourth aspect of the present invention, in the light emitting device according to the third aspect, the charge transporting substance is substantially continuously formed from the anode side to the cathode side of the light emitting region. It is characterized by having a configuration having a density distribution.

With the above structure, a region having a large hole transporting capability and a region having a large electron transporting capability are formed in the light emitting region in the direction from the anode side to the cathode side (film thickness direction). The recombination efficiency of electrons and holes increases.

According to a fifth aspect of the present invention, there is provided a light emitting device having a charge transport region between an anode and a cathode, wherein the charge transport region contains a charge transport material and the charge transport material. Wherein the charge transporting substance has a substantially continuous concentration distribution from the cathode side to the anode side of the charge transporting region.

With such a configuration, a region having a large hole transporting capability and a region having a large electron transporting capability are formed in the light emitting region, and the recombination efficiency of electrons and holes is increased. In addition, in the case of the above configuration, the charge transport region has a light emitting characteristic and also has the characteristics of the light emitting region.

According to a sixth aspect of the present invention, there is provided the light emitting device according to any one of the first to fourth aspects, wherein the light emitting region has a region where a substance contributing to the light emission does not exist. .

According to the above configuration, regions having different carrier transporting capabilities are formed in the light emitting region, so that the recombination efficiency of electrons and holes is further increased, and the light emitting efficiency can be improved.

According to a seventh aspect of the present invention, there is provided the light emitting device according to any one of the first to fourth aspects, wherein a portion of the light emitting region, which indicates a maximum concentration of the substance contributing to light emission, is the anode. And being separated from the cathode.

As in the above configuration, the portion showing the maximum concentration of the substance contributing to light emission is configured to be separated from both electrodes because the substance contributing to light emission is close to the anode or the cathode. This is because a substance that contributes to light emission may disappear without emitting light. Note that the portion indicating the maximum concentration of the substance contributing to light emission is preferably located substantially in the middle between the anode and the cathode.

According to an eighth aspect of the present invention, in the light emitting device according to the fifth aspect, the charge transporting region has a region where the charge transporting substance does not exist.

With the above structure, the recombination efficiency between electrons injected from the cathode and holes injected from the anode is further increased at the boundary between the region where the charge transporting substance exists and the region where the charge transporting substance does not exist. In addition, luminous efficiency can be improved.

According to a ninth aspect of the present invention, in the light emitting device according to the fifth aspect, a portion of the charge transporting region which shows the maximum concentration of the charge transporting substance is separated from the anode and the cathode. It is characterized by having.

According to a tenth aspect of the present invention, there is provided a lighting device, wherein the light emitting device according to the first to ninth aspects is used. With the above structure, a lighting device with improved luminous efficiency can be provided.

The invention according to claim 11 is a light-emitting element having a light-emitting region between an anode and a cathode, wherein the light-emitting region is composed of a substance contributing to light emission and a medium containing the substance. That is, in a direction parallel to the cathode surface and the anode surface, the concentration of the substance contributing to the light emission decreases substantially continuously from substantially the center to the periphery of the light emitting region.

According to a twelfth aspect of the present invention, there is provided the light emitting device according to the eleventh aspect, wherein the substance contributing to the light emission is:
The light emitting device has a configuration in which a plurality of substances are adjacent to each other in a direction parallel to the cathode surface and the anode surface, and the emission colors of the substances contributing to the plurality of light emission are different from each other.

With the above structure, since the concentration near the boundary between the plurality of light-emitting substances is small, the light-emitting substances do not mix with each other. A light-emitting element having excellent full-color display performance can be obtained.

According to a thirteenth aspect of the present invention, in the light emitting device according to the eleventh or twelfth aspect, the light emitting region further contains a charge transporting substance.

According to a fourteenth aspect of the present invention, in the light emitting device according to the thirteenth aspect, the concentration of the charge transporting substance is such that the concentration of the charge transporting substance in the light emitting region is in a direction parallel to the cathode surface and the anode surface. It is characterized in that it decreases from substantially the center toward the periphery.

Further, the invention of claim 15 is the invention of claims 11 to
15. The light emitting device according to claim 14, wherein the substance contributing to light emission has a concentration distribution substantially continuously from the cathode side to the anode side of the light emitting region. I have.

As described above, by giving a concentration distribution to the substance contributing to light emission in the light emitting region, the recombination region between the hole and the electron can be concentrated, so that the electron and the hole Recombination efficiency is increased, and luminous efficiency can be improved.

According to a sixteenth aspect of the present invention, in the light emitting device according to the fourteenth aspect, the charge transporting substance is substantially continuously formed from the cathode side to the anode side of the light emitting region. It is characterized by having a configuration having a density distribution.

With the above configuration, the recombination efficiency of electrons and holes is further increased, and the luminous efficiency can be improved.

The seventeenth aspect of the present invention relates to the eleventh to eleventh aspects.
17. The light emitting device according to claim 16, wherein the light emitting region has a region in which a substance contributing to the light emission does not exist.

The eighteenth aspect of the present invention relates to the eleventh to eleventh aspects.
18. The light emitting device according to claim 17, wherein the light emitting region has charge transporting performance.

The nineteenth aspect of the present invention relates to the eleventh to eleventh aspects.
19. The light emitting device according to claim 18, wherein the light emitting region is made of an organic material.

The invention according to claim 20 is the invention according to claims 11 to
19. The light emitting device according to claim 18, wherein the light emitting region is made of a polymer.

As described above, by forming the light-emitting region from an organic substance, more specifically, a polymer, it is possible to provide an organic light-emitting device having improved luminous efficiency.

According to a twenty-first aspect of the present invention, there is provided a display device, wherein the light emitting device according to the eleventh to twentieth aspects is used. With the above configuration,
A display device with improved luminous efficiency can be provided.

The invention of claim 22 is a method for manufacturing a light emitting device having a light emitting region between an anode and a cathode,
Arranging a medium on the anode or the cathode,
A step of forming a light emitting region by including a substance contributing to light emission in the medium.

Since the above method has a step of disposing the medium on an anode or a cathode and a step of including a substance contributing to light emission in the medium, the medium previously containing the substance contributing to light emission is used. It can be an effective method when it is difficult to arrange on the anode or the cathode.

A twenty-third aspect of the present invention is a method for manufacturing a light emitting device having a light emitting region between an anode and a cathode,
An arranging step of arranging a medium containing a charge transporting substance on the anode or the cathode; and a arranging step of forming a light emitting region by containing a substance contributing to light emission in the medium. .

By including a charge transporting substance in the medium as in the above method, a light emitting element capable of efficiently injecting and transporting charges can be obtained.

A twenty-fourth aspect of the present invention is a method for manufacturing a light emitting device having a light emitting region between an anode and a cathode,
Arranging a medium on the anode or the cathode,
A step of causing the medium to contain a substance contributing to light emission and a charge transporting substance.

According to a twenty-fifth aspect of the present invention, there is provided a method of manufacturing a light emitting device having a light emitting region between an anode and a cathode,
The method is characterized by comprising an arrangement step of disposing a medium containing a charge transporting substance on the anode or the cathode, and a step of containing a substance contributing to light emission and a charge transporting substance in the medium.

The charge of the charge transporting substance contained in the medium in the arranging step and the charge of the charge transporting substance in the containing step may be the same or different.

A twenty-sixth aspect of the present invention is a method for manufacturing a light emitting device having a charge transport region between an anode and a cathode, the method comprising: arranging a medium on the anode or the cathode; And a step of containing a charge-transporting substance.

According to a twenty-seventh aspect of the present invention, there is provided a method for manufacturing a light emitting device according to the twenty-second or twenty-third aspect,
The method is characterized in that in the containing step, the substance contributing to light emission is contained by penetrating into the medium.

According to a twenty-eighth aspect of the present invention, in the method for manufacturing a light-emitting device according to the twenty-fourth aspect, in the containing step, the substance contributing to light emission and the charge transporting substance are permeated into a medium. It is characterized in that it is contained by the following.

According to the above-described method, the substance contributing to the light emission, or the substance contributing to the light emission and the charge transporting substance are transferred from the anode side to the cathode side of the light emitting region, or
It is possible to obtain a light-emitting element having a substantially continuous concentration distribution from the cathode side to the anode side.

According to a twenty-ninth aspect of the present invention, there is provided a method for manufacturing a light emitting device according to the twenty-second or twenty-third aspect,
In the containing step, a solution obtained by dissolving the substance contributing to light emission in a solvent is permeated by contact with the medium.

The invention according to claim 30 is the method for manufacturing a light emitting device according to claim 24, wherein in the containing step, the substance contributing to light emission and the charge transporting substance are dissolved in a solvent. The solution thus obtained is characterized by allowing the solution to permeate by contact with the medium.

According to the above method, the substance contributing to the light emission, or the substance contributing to the light emission and the charge transporting substance can be moved from the anode side to the cathode side or from the cathode side to the anode side in the light emitting region. A light emitting element having a substantially continuous concentration distribution can be obtained.

According to a thirty-first aspect of the present invention, there is provided a method for manufacturing a light emitting device according to the twenty-second or twenty-third aspect,
In the containing step, a substance contributing to light emission is made to penetrate into the medium by an inkjet method.

According to the above method, a substance contributing to light emission is permeated into a medium by an ink jet method. Therefore, when a polymer having a high viscosity is used as a precursor of the medium, the polymer solution and the polymer solution contribute to light emission. It is not necessary to apply the substance by an inkjet method. Therefore,
It is possible to easily form a fine pattern without clogging the ink jet nozzle.

(Second invention group)
Based on the idea that the light-emitting molecules diffused throughout the organic layer are concentrated in a specific area and that increasing the surface area of the organic layer leads to higher efficiency of the polymer organic light-emitting device, By dispersing light-emitting molecules on the surface or near the surface of the planarized organic layer, high-luminance light emission can be realized, and the above problem has been solved.

That is, the invention of claim 32 is a light-emitting element having a light-emitting region between an anode and a cathode, wherein the light-emitting region contains a substance contributing to light emission, and is provided between the anode and the cathode. Is characterized by having a consolidating means for consolidating the substance contributing to light emission into a specific region.

More specifically, the invention according to claim 33 is a light emitting device having a light emitting region between an anode and a cathode,
At least one of the anode side and the cathode side of the light emitting region is made porous, and a material contributing to light emission is provided on the porous surface of the light emitting region.

A thirty-fourth aspect of the present invention is a light emitting device having a light emitting region between an anode and a cathode, wherein at least one of the anode side and the cathode side of the light emitting region is made porous, The light-emitting region is characterized in that it has a substance contributing to light emission near the porous surface of the light-emitting region.

With the above structure, substances contributing to light emission can be concentrated on a specific region, specifically on or near the surface of the porous light emitting region.
In addition, since the surface area of a recombination region between holes and electrons, in which a substance contributing to light emission is present, is increased, high-luminance light emission can be realized.

According to a thirty-fifth aspect of the present invention, there is provided the light-emitting device according to the thirty-third or thirty-fourth aspect, wherein the light-emitting region has a charge-transporting substance on a porous surface of the light-emitting region. Features.

According to a thirty-sixth aspect of the present invention, in the light-emitting device according to the thirty-third or thirty-fourth aspect, a flattening layer made of a charge transporting substance is provided on the porous surface of the light emitting region. It is characterized by having a configuration having.

With the above structure, it is possible to prevent leakage current and to efficiently inject and transport holes or electrons. Further, the bonding surface with the adjacent anode or cathode can be kept smooth by the flattening layer.

The present invention according to claim 37 is a light emitting device having a charge transport region between an anode and a cathode, wherein at least one of the anode side and the cathode side of the charge transport region is made porous. It is characterized by having a configuration.

With such a configuration, the efficiency of injection of charges injected from the electrodes (anode and cathode) into the charge transport region can be improved. Note that, in the case of the above configuration, the charge transport region is a region having light-emitting characteristics, and also has characteristics of a light-emitting region.

According to a thirty-eighth aspect of the present invention, in the light emitting device according to the thirty-seventh aspect, the charge transport region is a hole transport region.

[0085] The invention of claim 39 is the light emitting device according to claim 37, wherein the charge transport region is an electron transport region.

The invention according to claim 40 is the invention according to claims 33 to
37. The light emitting device according to claim 36, wherein the light emitting region is made of an organic material.

The invention of claim 41 is the invention of claims 33 to
37. The light emitting device according to claim 36, wherein the light emitting region is made of a polymer.

The invention according to claim 42 is a light emitting device having a light emitting region between an anode and a cathode, wherein at least one of the anode side and the cathode side of the light emitting region is roughened, The light-emitting region is characterized in that it has a material that contributes to light emission on the roughened surface.

The invention according to claim 43 is a light-emitting element having a light-emitting region between an anode and a cathode, wherein at least one of the anode side and the cathode side of the light-emitting region is roughened, The light emitting device is characterized in that it has a substance contributing to light emission near the roughened surface of the light emitting region.

With such a configuration, the surface area of the recombination region between holes and electrons, in which a substance contributing to light emission is present, is increased, so that high-luminance light emission can be realized.

The invention according to claim 44 is the light-emitting device according to claim 42 or 43, wherein a flattening layer made of a charge transporting substance is provided on the roughened surface of the light-emitting region. It is characterized by having.

The invention according to claim 45 is a light emitting device having a charge transport region between an anode and a cathode, wherein at least one of the anode side and the cathode side of the charge transport region is roughened. It is characterized by having a configuration.

With such a configuration, the efficiency of injection of charges injected from the electrodes (anode and cathode) into the charge transport region can be improved. Further, when the light emitting region is arranged on the roughened charge transport region, the contact area between the light emitting region and the charge transport region is improved, so that the hole injected from the anode into the light emitting region is reduced. The injection efficiency is improved.

The invention according to claim 46 is the light-emitting device according to claim 45, wherein the charge transport region is a hole transport region.

The invention according to claim 47 is the light emitting device according to claim 45, wherein the charge transport region is an electron transport region.

Further, the invention of claim 48 is based on claims 42 to
The light emitting device according to claim 44, wherein the light emitting region is made of an organic material.

Further, the invention of claim 49 is based on claims 42 to
The light emitting device according to claim 44, wherein the light emitting region is made of a polymer.

Further, the invention of claim 50 is a display device, wherein the light emitting device according to any one of claims 32 to 49 is used.

The invention according to claim 51 is a lighting device, characterized by using the light emitting element according to any one of claims 32 to 49.

With the above structure, a display device and a lighting device with improved luminous efficiency can be provided.

The invention of claim 52 is a method of manufacturing a light emitting device having a light emitting region between an anode and a cathode,
A method for manufacturing a light-emitting element having a light-emitting region between an anode and a cathode, a medium disposing step of disposing a medium for forming the light-emitting region on the anode or the cathode,
A step of making at least a part of the medium porous.

The invention according to claim 53 is a method for manufacturing a light emitting device having a light emitting region between an anode and a cathode,
A medium disposing step of disposing a medium on the anode or the cathode, a porous forming step of making at least one of the anode side and the cathode side of the medium porous, and a porous surface of the medium, An arrangement step of arranging a substance contributing to light emission and forming a light emitting region using the medium and the substance contributing to light emission.

The invention according to claim 54 is a method for manufacturing a light emitting device having a light emitting region between an anode and a cathode,
A medium disposing step of disposing a medium on the anode or the cathode, a porosifying step of making at least one of the anode side and the cathode side of the medium porous, and a step near the porous surface of the medium. Containing a substance contributing to light emission, forming a light-emitting region by the medium and the substance contributing to light emission, and arranging a charge-transporting substance on a porous surface of the light-emitting region. And having the following.

According to the above method, substances that contribute to light emission can be concentrated on the surface or near the surface of the porous light-emitting region. In addition, the surface area of a recombination region between holes and electrons in which a substance contributing to light emission is present can be increased, so that a light-emitting element that achieves high-luminance light emission can be obtained.

The invention according to claim 55 is a method for manufacturing a light emitting device according to claim 53 or 54, wherein
The method is characterized by including an arrangement step of arranging a charge transporting substance on the porous surface of the light emitting region.

The invention of claim 56 is a method of manufacturing a light emitting device according to claim 53 or claim 54, wherein
A flattening layer forming step of forming a flattening layer made of a charge transporting substance on the light emitting region is provided.

By forming a flattening layer above the light emitting region as in the above-described method, it is possible to prevent leakage current, to efficiently inject and transport holes or electrons, and to make the adjacent anode or cathode adjacent. A light-emitting element that can maintain a smooth bonding surface with the light-emitting element can be obtained.

According to a fifty-seventh aspect of the present invention, there is provided a method for manufacturing a light emitting device according to the fifty-third or fifty-fourth aspect,
The medium arranging step is a step of arranging a medium containing a substance soluble in a specific solvent, and the porousizing step is a step of making the substance porous by eluting the substance with the solvent. It is characterized by:

The invention of claim 58 is a method of manufacturing a light emitting device having a light emitting region between an anode and a cathode,
The method is characterized by comprising a medium arranging step of arranging a medium on the anode or the cathode, and a roughening step of roughening a part of the medium.

The invention according to claim 59 is a method for manufacturing a light emitting device having a light emitting region between an anode and a cathode,
A medium arranging step of arranging a medium on the anode or the cathode; a roughening step of roughening at least one of the anode side and the cathode side of the medium; and a rough surface of the medium, which contributes to light emission. An arrangement step of arranging a substance and forming a light-emitting region using the medium and the substance contributing to light emission.

The invention according to claim 60 is a method for manufacturing a light emitting device having a light emitting region between an anode and a cathode,
A medium arranging step of arranging a medium on the anode or the cathode; a roughening step of roughening at least one of the anode side and the cathode side of the medium; And forming a light emitting region with the medium and the substance contributing to light emission.

According to the above method, the substance contributing to light emission can be concentrated on or near the surface of the roughened light emitting region. Since the surface area of the recombination region with electrons is increased, a light-emitting element capable of realizing high-luminance light emission can be obtained.

The invention of claim 61 is the method for manufacturing a light emitting device according to claim 59 or claim 60, wherein:
A flattening layer forming step of forming a flattening layer made of a charge transporting substance on the light emitting region is provided.

According to the above-described method, a light emitting element which can prevent leakage current, efficiently inject and transport holes or electrons, and maintain a smooth junction surface with an adjacent anode or cathode can be obtained. be able to.

The invention according to claim 62 is the method for manufacturing a light emitting device according to claim 59 or claim 60, wherein
The roughening step is characterized in that the light emitting region is roughened by dry etching. By the dry etching, the light emitting region can be easily roughened.

[0116]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment in First Invention Group) The first invention group of the present invention will be described below with reference to the drawings.

In the following embodiments (the same applies to the second invention group), an organic light-emitting element will be described. However, the concept of the present invention is not limited to the organic light-emitting element, but may be, for example,
The present invention can be similarly applied to an inorganic light emitting element or the like which forms a light emitting region by dispersing an inorganic light emitting material in an organic binder.

[Embodiment 1-1] FIG. 1 is a schematic sectional view of an organic light-emitting device according to Embodiment 1-1 of the present invention.
As shown in FIG. 1, an organic light emitting element 10 includes an anode 2 formed on a substrate 1 and a cathode 4 disposed opposite to the anode 2.
And a light-emitting region 3 disposed between the anode 2 and the cathode 4.

The light emitting region 3 has a configuration including a polymer 3A, a light emitting molecule 3G which is a substance contributing to light emission, and a charge transporting substance 3F. FIG. 1 shows only one kind of light-emitting molecule.

The light emitting molecules 3G and the charge transporting substance 3F have a concentration distribution in the thickness direction of the light emitting region 3 (from the anode 1 to the cathode 4). That is, the light emitting area 3
Among them, the concentration of the luminescent molecules 3G and the charge transport material 3F is high on the side close to the cathode 4 (upper side in the figure), and low on the side close to the anode 2 (lower side in the figure). Also, preferably, the light emitting region 3
It is preferable to have a region in which the light emitting molecules 3G and the charge transporting substance 3F do not exist in the film thickness direction. That is,
In the light emitting region 3, it is preferable that there is a region on the side close to the anode 2 where the light emitting molecules and the charge transport material do not exist and only the polymer 3A exists.

It is assumed that the light-emitting molecules 3G and the charge transporting substance 3F have a concentration distribution in the film thickness direction. The conductive material 3F may be uniformly distributed in the film thickness direction.

Further, the light emitting region 3 is composed only of the polymer 3A and the light emitting molecule 3G (the charge transporting substance 3F is not present), and the light emitting molecule 3G has a distribution in the concentration in the film thickness direction. Good.

The light emitting mechanism of the organic light emitting device of the present invention is as follows. That is, in the organic light-emitting device 10 shown in FIG. 1, when a positive voltage is applied to the anode 2 and a negative voltage is applied to the cathode 4, holes from the anode 2 and electrons from the cathode 4 emit light.
Is injected into. And the injected holes are on the cathode 4,
The electrons flow toward the anode 2. Holes and electrons are recombined in the light emitting region 3, and in response to this, fluorescence or phosphorescence is emitted from the light emitting molecules 3 G in the light emitting region 3.

Here, the following points can be cited as main factors for determining the light emission current efficiency (light emission efficiency with respect to the injected current). (1) Recombination efficiency of holes and electrons with respect to injection current (2) Exciton generation efficiency of luminescent molecules due to recombination (3) Emission quantum efficiency from excitons of luminescent molecules

Of the above, for (2) and (3),
It is almost determined by the properties of the light emitting molecule itself.

On the other hand, the recombination efficiency of holes and electrons in (1) is most affected by the balance between holes and electrons. In other words, if the balance between holes and electrons is poor, excess carriers will reach the opposite electrode without being recombined in the light emitting region even if injected from the electrode, resulting in a useless current that does not contribute to light emission.

Therefore, if the mobility of each carrier in the light emitting region is increased, holes and electrons flow in a well-balanced manner,
Luminous efficiency is also improved. Specifically, the mobility of the hole is 1
× 10 ⁻⁷ cm ² / V · s or more, electron mobility of 5 × 10 ⁻⁸ cm ² / V
・ It is preferably at least s.

In view of the light emitting mechanism described above, when there are a region having a large hole transporting ability and a region having a large electron transporting ability in the thickness direction in the light emitting region, specifically, the anode side in the light emitting region is located on the anode side. When the hole transporting ability is large and the electron transporting ability is large on the cathode side, holes and electrons injected from the anode and the cathode, respectively, recombine locally near the interface between the two regions.

Therefore, as shown in FIG.
Preferably, the charge transporting substance 3F has a concentration distribution in the film thickness direction, and preferably has a region in which the light emitting molecule 3G and the charge transporting substance 3F are not present in the light emitting region 3 in the film thickness direction. Since regions having different carrier transporting abilities are formed in the region 3, the recombination efficiency of the above (1) further increases, and the luminous efficiency also improves.

[Embodiment 1-2] FIG. 2 is a schematic diagram showing a configuration of an organic light emitting device according to Embodiment 1-2 of the present invention, and FIG. FIG. 2
2B is a sectional view taken along line AA of FIG. 2A.

As shown in FIG. 2, the organic light emitting device 20
An anode 22 formed in a stripe shape on a substrate 21; a light emitting region 23 formed on the anode 22;
3 and a cathode 24 formed in a stripe shape so as to be orthogonal to the anode 22.

The substrate 21 is provided with the organic light emitting device 2 of the present invention.
A transparent substrate such as glass or a resin film such as polycarbonate, polymethyl methacrylate, and polyethylene terephthalate;
Alternatively, an opaque substrate such as silicon can be used.

At least one of the anode 22 and the cathode 24 must be transparent or translucent.
Light emitted from the light emitting region 23 is extracted to the outside through one or both electrodes.

As the anode 22, usually, a transparent electrode such as indium tin oxide (ITO) or tin oxide is often used, but a metal electrode such as Ni, Au, Pt, or Pd may be used. For the purpose of improving the transparency or reducing the resistivity of the ITO film, a film forming method such as sputtering, electron beam evaporation, or ion plating is employed. The film thickness is determined from the required sheet resistance value and visible light transmittance. However, since the organic light emitting element has a relatively high driving current density, it is used at a thickness of 1000 mm or more to reduce the sheet resistance value. Is often done.

As the cathode 24, Al, Ag, Au
Alloys of metals having low work functions such as metals such as MgAg alloys and AlLi alloys and metals having relatively large and stable work functions, and metals having low work functions and metals having high work functions such as Li / Al and LiF / Al. A stacked electrode or the like can be used. For forming these cathodes, a vapor deposition method or a sputtering method is preferable.

The anode 22 and the cathode 24 are striped electrodes orthogonal to each other. When a voltage is applied to the selected anode and cathode in the forward direction, the light-emitting region at the intersection of the two electrodes becomes the applied voltage. It emits light at the appropriate brightness.

Further, in the present embodiment, the substrate 21 is
/ Anode 22 / light emitting region 23 / cathode 24 are stacked in this order. However, it is not always necessary to stack in this order, and substrate 21 / cathode 24 / light emitting region 23 / anode 22 may be arranged in this order from the bottom.

When only the electrode on the substrate 21 side, that is, the anode 22 is transparent and the cathode 24 is opaque, the substrate 21 needs to be a transparent substrate in order to extract light emission to the outside.

Next, the light emitting area 23 will be described. The light emitting region 23 includes a polymer 23A, a light emitting molecule (red) 23R, a light emitting molecule (green) 23G, and a light emitting molecule (blue).
23B. The polymer 23A is continuously arranged in the in-plane direction of the light emitting region 23, and the light emitting substance 23
R • 23G • 23B are the cathode 24 and the anode 2
A plurality is arranged adjacent to each other in a direction parallel to 2. Further, the concentrations of the light emitting substances 23R, 23G, and 23B have distributions that decrease substantially continuously from the substantially center to the periphery of the light emitting region in a direction parallel to the cathode 24 and the anode 22, respectively. Have.

Next, a method for manufacturing an organic light emitting device according to Embodiment 1-2 of the present invention will be described. FIG. 3 is a schematic sectional view illustrating the method for manufacturing the organic light emitting device according to Embodiment 1-2 of the present invention.

(1) First, as shown in FIG. 3A, an anode 22 made of ITO or the like is formed on a substrate 21 by a film forming method such as sputtering, electron beam evaporation, or ion plating.

(2) Next, as shown in FIG. 3B, the anode 22 is formed in a desired pattern (in the form of a stripe here).
Is patterned. For example, in the case of an ITO electrode, after patterning by a normal photolithography using a photoresist, etching is performed with hydroiodic acid or the like.

(3) Next, as shown in FIG. 3C, a polymer 23A made of, for example, poly-N-vinylcarbazole is formed on the anode 22. The film may be formed by any method such as an evaporation method, a sputtering method, and a coating method, but is mainly formed by a coating method. That is, a solution of poly-N-vinylcarbazole in a solvent such as toluene or chloroform is applied onto the substrate 1 by a spin coating method or the like. The thickness of the polymer 3A is not particularly limited, but is preferably about 500 to 3000 °.

(4) Next, as shown in FIG. 3 (d), after forming the polymer 23A, luminescent molecules having a desired luminescent color are permeated into desired positions. Specifically, RGB
In the case of manufacturing a full-color panel, first, a solution in which red light-emitting molecules 23R are dissolved in a solvent is ejected by an ink-jet method using ink heads 27, and among the striped anodes 22 made of ITO, a red electrode ( Drop on every other) and allow to penetrate.

(5) Next, as shown in FIG. 3E, similarly, a solution of the green light-emitting molecules 23G is discharged onto the green striped anode 22 using the ink head 27.

(6) Next, as shown in FIG. 3 (f), a solution of the blue light-emitting molecule 23B is similarly applied to the anode 22 for blue.
Discharge upward. The order of dropping red, green, and blue light-emitting molecules is not particularly limited, and they may be dropped in any order. Further, it is preferable to perform heat treatment after the light-emitting molecules are dropped. That is, the luminescent molecules 23R / 23G /
The penetration of 23B into the polymer 23A can be promoted. Further, in order to promote penetration into the polymer 23A, it is preferable to use a liquid in which the polymer 23A is soluble as a solvent for dissolving the luminescent molecules.

(7) Next, as shown in FIG. 3G, a striped cathode 24 is formed so as to be orthogonal to the striped anode 22. Film formation is performed by an evaporation method, a sputtering method, or the like using an evaporation mask on which a desired pattern is formed.

In Embodiment 1-2, the light-emitting molecules are made to permeate the polymer. However, the light-emitting molecules and the charge transporting substance may be made to permeate the polymer. Further, a luminescent molecule may be permeated into a polymer in which a charge transporting substance is dispersed.

According to the above method, the luminescent molecules 23R and 23G
Since 23B is penetrated into the polymer by the ink jet method, it is not necessary to apply a polymer solution having a large viscosity by the ink jet method. Therefore, the light emitting molecules can be applied without clogging the nozzles of the ink jet, and a fine pattern can be formed.

Next, the structure of the light emitting region of the organic light emitting device manufactured by the above manufacturing method will be described with reference to FIG. FIG. 5 is a schematic diagram for explaining the concentration distribution of the light emitting region of the organic light emitting device according to Embodiment 1-2 of the present invention.

That is, as shown in FIG. 5, in the in-plane direction of the light emitting region 23 (direction parallel to the electrodes), the light emitting molecules (red) 23R and the light emitting molecules (green) 23G and the luminescent molecules (blue) 23B are dispersed, but the concentration distribution of the luminescent molecules 23R, 23G, and 23B is maximum at a position substantially above the center of each of the anodes 22 and becomes closer to both sides of each of the anodes 22. And each luminescent molecule 2
The concentration of 3R.23G.23B decreases.

With such a configuration, each light emitting molecule 2
Since the concentration near each boundary between 3R, 23G, and 23B is small, the light-emitting molecules 23R, 23G, and 23B do not mix with each other, the color mixture is small, and the full-color display performance is excellent.

Further, since the light-emitting molecules 23R, 23G, and 23B are penetrated into the polymer 23A by the ink-jet method using the ink-jet 27, the light-emitting molecules 23R, 23G, and 23B The side has a higher concentration than the anode 22 side.

Therefore, similarly to Embodiment 1-1,
In the organic light-emitting device according to Embodiment 1-2, the efficiency of recombination between electrons and holes is increased, and the light-emitting efficiency is improved.

FIG. 4 is a schematic sectional view showing another example of the method for manufacturing an organic light emitting device according to Embodiment 1-2 of the present invention.

FIG. 4C shows a process similar to that of FIG. 3 except that the polymer 3A is formed on the substrate 1 on which the anode 2 is formed.
To form

Next, the luminescent molecules 3R, 3G, 3B are made to permeate the polymer 3A by the following method.

First, a striped anode 2 made of ITO was used.
Of these, after the mask 8 provided with an opening only on the red electrode is placed on the substrate 1, a vapor treatment is performed as shown in FIG. 4D using a solution in which red light-emitting molecules are dissolved in a solvent. Do. Thus, the red light-emitting molecules 3R penetrate into desired positions.

Subsequently, in a similar manner, FIG.
As shown in (f), green light-emitting molecule 3G and blue light-emitting molecule 3
Infiltrate B. The order of the vapor treatment of the red, green, and blue light-emitting molecules is not particularly limited, and they may be performed in any order. Further, it is preferable to perform a heat treatment after the vapor treatment of the luminescent molecules. That is, the heat treatment can promote the penetration of the luminescent molecules 3B to 3D into the polymer 3A. Furthermore, polymer 3A
It is preferable to use a liquid in which the polymer 3A is soluble as a solvent for dissolving the luminescent molecules in order to promote the penetration into the polymer.

Finally, as in the case of FIG. 3, a striped cathode 4 is formed so as to be orthogonal to the striped anode 2.

In the above description, the light emitting molecules are made to permeate the polymer. However, the light emitting molecules and the charge transport material may be made to permeate the polymer. Further, a light emitting molecule may be permeated into a polymer in which a charge transport material is dispersed.

Another example of the method for manufacturing an organic light emitting device according to the present invention is a method in which luminescent molecules are permeated into a polymer by a printing method.

That is, in FIG. 4D to FIG.
Instead of allowing R.3G.3B to permeate the polymer 3A by a vapor treatment, a solution of a luminescent molecule is applied onto the polymer 3A by offset printing or screen printing, and the solution is permeated.

Also in this case, it is preferable to perform a heat treatment after the printing of the luminescent molecules, as described above. Further, it is preferable to use a liquid in which the polymer 3A is soluble as a solvent for dissolving the light emitting molecules. Further, instead of making the light emitting molecule permeate the polymer, the light emitting molecule and the charge transport material may be made to permeate the polymer, or the light emitting molecule may be made to permeate the polymer in which the charge transport material is dispersed.

[Embodiment 1-3] FIG. 6 is a schematic sectional view of an organic light emitting device according to Embodiment 1-3 of the present invention.
The present embodiment 1-3 is different from the above-described embodiment 1-2 in that the light-emitting molecules 23R, 23G, and 23B
In addition, the charge transporting substances 23E exist. Here, the polymer 23A and the charge transporting substance 23E are continuously arranged in the in-plane direction of the light emitting region 23. In other words, the charge transporting substance 23E is uniformly dispersed in the polymer 23A. Light-emitting molecule 23R
23G and 23B are distributed on the respective striped anodes 22 in the same manner as in Embodiment 1-2.

[Embodiment 1-4] FIG. 7 is a schematic sectional view of an organic light-emitting device according to Embodiment 1-4 of the present invention.
7 differs from FIG. 6 in that the charge transporting material 23E is not continuously arranged in the in-plane direction of the light-emitting region 23, but in the in-plane direction like the light-emitting molecules 23R, 23G, and 23B. Is to have a distribution in concentration. That is, the charge transporting substance 23E also exists at a high concentration in the portion where the concentration of the light emitting molecules 23R, 23G, and 23B is high.

[Common Matters Regarding Embodiments 1-2 to 1-4] As the polymer material, a charge transporting polymer is preferable, and a hole transporting polymer is particularly preferable.
The hole transporting polymer has a carrier mobility of 1 ×
Those having a ^{density of} 10 ⁻⁷ cm ² / V · s or more are preferable.
N-vinyl carbazole is preferred.

When a hole transporting polymer is used, an electron transporting material is preferably used as the charge transporting material.
Further, the carrier mobility of the electron transporting material is 5 × 10 ⁻⁸ cm.
Those having a value of ² / V · s or more are preferred. In particular, oxazole derivatives, oxadiazole derivatives, triazole derivatives,
Pyrazine derivatives, aldazine derivatives, quinolinol complexes and their derivatives are preferred. Further, the content of the electron transporting material is preferably 30 to 120% by weight based on the polymer. That is, when the content is less than 30% by weight, the electron transporting ability is not sufficient, and when the content is more than 120% by weight, the dispersibility in the polymer is deteriorated.

As the luminescent molecule, a fluorescent substance or a phosphorescent substance which emits light in response to hole / electron recombination may be used. Particularly, a substance which exhibits a strong fluorescent or phosphorescent light includes a cyanine dye, a merocyanine dye and a styryl dye. , Anthracene derivatives, porphyrin derivatives, phthalocyanine derivatives, coumarin, DCM, Nile Red, and other dyes and laser dyes. Further, as the light-emitting molecule, a substance in which the ionization potential of the light-emitting molecule is lower than the ionization potential of the hole transporting polymer and the electron affinity of the light-emitting molecule is higher than the electron affinity of the electron transport material is preferable.

[Embodiment 1-5] FIGS. 8 to 10 are schematic sectional views of an organic light emitting device according to Embodiment 1-5 of the present invention. 8 to 10, 25 is a hole injection layer,
26 is an electron injection layer, 23G is a light emitting molecule, 23H is a hole transporting material, and 23I is an electron transporting material.

The hole injection layer 25 is inserted for the purpose of assisting hole injection from the anode 22 to the light emitting region 23. The hole injection layer 25 has an ionization potential (Ip (h)) and an ionization potential of the polymer.
It is preferable to use a material in which the relationship between (Ip (p)) and the ionization potential of the anode or the work function (Ip (a)) satisfies Ip (a) <Ip (h) <Ip (p). In particular, it is preferable that the material be at least one of a polyaniline derivative, a polythiophene derivative, and amorphous carbon.

The electron injection layer 26 is inserted for the purpose of assisting the electron injection from the cathode 24 into the light emitting region 23. As the electron injection layer 26, it is desirable to use a material whose electron affinity or work function is smaller than the work function of the cathode. In particular, it is preferable to be composed of at least one of dilithium phthalocyanine, disodium phthalocyanine, and an organic boron complex compound.

The hole transport material 23H is introduced for the purpose of assisting the injection of holes from the anode 22 to the light emitting region 23, similarly to the hole injection layer. However, unlike the hole injection layer 25, it is not inserted as a layer between the anode 22 and the light emitting region 23, but is directly dispersed in the light emitting region.

As the hole transporting material 23H, it is preferable to use a material whose ionization potential is lower than the ionization potential of the polymer. Further, the content of the hole transport material is 10 to 1 with respect to the polymer.
Preferably it is 20% by weight. That is, if the amount is less than 10% by weight, sufficient hole injection cannot be performed, and if the amount is more than 120% by weight, dispersibility in a polymer becomes poor.

The hole injection layer 25, the electron injection layer 26,
The effect of introducing the hole transport material 23H will be described with reference to the drawings. 11 to 14 are energy diagrams of the organic light emitting device according to the present invention.

FIG. 11 is an organic light-emitting device having a constitution of anode / light-emitting region (hole transporting polymer + electron transport material + light-emitting molecule (light-emitting material)) / cathode. FIG.
1 shows an energy diagram of an organic light emitting device having a structure of a light emitting region (hole transporting polymer + electron transporting material + light emitting molecule) / cathode and an operation mechanism thereof. As described above, when a voltage is applied to the organic light emitting device, holes are injected from the anode and electrons are injected from the cathode into the light emitting region. More specifically, FIG.
As shown in FIG. 1, both carriers have a smaller injection barrier, that is, holes are injected into the hole transporting polymer in the light emitting region, and electrons are injected into the electron transporting material in the light emitting region. Here, the smaller the injection barrier of both carriers (holes and electrons), the easier the injection occurs, and the lower the driving voltage. Therefore, even if the current efficiency is the same, the power efficiency of light emission (the efficiency of light emission with respect to the applied power) can be improved by reducing the drive voltage. Therefore, for example, when a hole injection layer having an ionization potential between the anode and the hole transporting polymer is inserted, as shown in FIG. 12, the hole injection barrier is relaxed, and the driving voltage can be reduced. Further, when the hole injection barrier is larger than the electron injection barrier as shown in FIG. 11, the hole injection barrier and the electron injection amount are well balanced by reducing the hole injection barrier. Improvements in efficiency can also be expected. Also,
FIG. 13 is an energy diagram of an organic light emitting device having a structure of anode / light emitting region (hole transporting polymer + electron transporting material + luminous molecule) / electron injection layer / cathode. Like the hole injection barrier, the electron injection barrier can be made smaller as shown in FIG. 13 by inserting an electron injection layer having a smaller electron affinity than the cathode,
The drive voltage can be reduced and the luminous efficiency can be improved. On the other hand, FIG.
Reference numeral 4 is an energy diagram of an organic light emitting device having a structure of anode / light emitting region (hole transporting polymer + hole transporting material + electron transporting material + luminescent molecule) / cathode. In this case, since the ionization potential of the hole transporting material is smaller than that of the hole transporting polymer, holes are directly injected from the anode into the hole transporting material in the light emitting region as shown in the figure, and when injected into the hole transporting polymer. In comparison, the injection barrier becomes smaller. Therefore, similar to the case where the hole injection layer is inserted,
The drive voltage can be reduced and the current efficiency can be improved.

Of course, a combination of the above structures, ie, both a hole injection layer and an electron injection layer are inserted, or an electron injection layer is further inserted with the light emitting region as a hole transporting polymer + hole transport material + electron transport material + light emitting molecule. Alternatively, a configuration may be adopted in which the concentration of the light-emitting molecules and each charge transport material has a distribution in the thickness direction of the light-emitting region.

In the above embodiments 1-1 to 1-5,
Although the example of the organic light-emitting element of the simple matrix system has been described, for example, the light-emitting element having the above structure may be formed on a thin film transistor to form an active matrix display panel.

Next, an experimental example based on the above embodiment will be described in more detail. (Experimental Example 1) An organic light-emitting device was manufactured as follows in accordance with the process of Embodiment 1-1 shown in FIG. That is, a glass substrate having a thickness of 0.7 mm was used as the substrate 1, and ITO was formed thereon as the anode 2 by a sputtering method. The thickness of the ITO was about 1000 Å, the sheet resistance was about 15 Ω / □, and the width of the ITO was 30 mm by photolithography.
It was patterned into a 0 μm stripe.

Next, after the above substrate was washed and subjected to oxygen plasma treatment, poly-N-vinylcarbazole (PVK) (molecular weight: about 28,000) was formed as a polymer 3A. P
VK is a hole transporting polymer, and its carrier mobility is about 2 × 10 ⁻⁶ cm ² / V · s. Film formation is PV
This was performed by a spin coating method using a solution in which 300 mg of K was dissolved in 30 ml of toluene. Spin coating is performed at 500 rpm for 10 seconds in a sealed state using a spin.
The test was performed under the conditions of 00 rpm and 30 seconds.

Next, heat treatment was performed at 110 ° C. for 1 minute using a hot plate. The PVK film thickness was about 1000 °.

Next, using a commercially available ink-jet printer, luminescent molecules were dropped at desired positions on the ITO electrodes to form luminescent regions. Light emitting molecule for red (3R)
Coumarin 6 for green (3G) and coumarin 47 for blue (3B). Each luminescent molecule was ejected from the ink head 7 using a solution in which 1 mg was dissolved in 10 ml of chloroform.
When each luminescent molecule was dropped, heat treatment was performed at 110 ° C. for 1 minute using a hot plate each time.

Finally, a Li / Al laminated electrode was formed as the cathode 4 by vacuum evaporation. Deposition is about 5 x 1 vacuum
It is performed under 0 ^-6 Torr.
Al is deposited at about 30 ° / sec.
At 1500 °. The shape of the cathode is a stripe shape perpendicular to the anode 2 by a vapor deposition mask, and the width is 300 μm.
m.

Regarding the energy level of each material,
TO ionization potential is 4.9 eV, PVK ionization potential is 5.6 eV, and electron affinity is 2.0
eV, the ionization potential of Nile Red is 5.3e
V, the electron affinity is 3.5 eV, the ionization potential of coumarin 6 is 5.4 eV, the electron affinity is 2.9 eV, the ionization potential of coumarin 47 is 5.4 eV, and the electron affinity is 2.5 eV. Li work function is 2.9e
The work functions of V and Al are 4.3 eV.

Further, in order to examine the concentration distribution of the luminescent molecules in the luminescent region 3, elemental analysis in the film thickness direction of the portion where the coumarin 6 was dropped showed that the amount of sulfur contained only in the coumarin 6 was lower than that of the cathode. It was found that the coumarin 6 did not exist near the anode, and the coumarin 6 did not exist near the anode.

In the organic light emitting device thus manufactured,
1 in the forward direction between the selected striped anode and cathode
When a voltage of about 0 V was applied, the portion (pixel) sandwiched between both electrodes emitted bright light in colors (Nile red: red, coumarin 6: green, coumarin 47: blue) corresponding to the luminescent molecules, respectively. That is, a simple matrix display capable of emitting light at a desired position (pixel) in a desired color could be manufactured.

Further, the current efficiency (cd / A) of each emission color,
Drive voltage at luminance of 100 cd / m ^{2 and} luminance of 100 c
Table 1 shows the power efficiency (lm / W) at d / m ² .

[Table 1]

(Experimental Example 2) In Example 1, instead of forming PVK as a polymer 3A, 2- (4-biphenyl) -5- (4-tertbutylphenyl) -1,3,3 was used.
PVK in which 4-oxadiazole (PBD) was dispersed was formed into a film. PBD is an electron transporting material, and its carrier mobility is about 2 × 10 ⁻⁶ cm ² / V · s. The ionization potential is 6.1 eV and the electron affinity is 2.4 eV.
It is. The film is formed by PVK 300 mg and PBD 180 m
g of toluene and chloroform 1: 1 mixed solvent 30 ml
Was carried out by a spin coating method under the same conditions as in Experimental Example 1 using a solution dissolved in. Table 1 shows the characteristics of this device.

(Experimental Example 3) In Example 1, instead of dropping light emitting molecules, each light emitting molecule and PBD (electron transport material) were used.
Was added dropwise. That is, 1 mg of Nile Red +
PBD100mg, 1mg coumarin 6 + PBD100
mg, 1 mg of coumarin 47 + 100 mg of PBD, 30 ml of a mixed solvent of toluene and chloroform 1: 1 respectively
Was dissolved and dropped on PVK by an inkjet method. Table 1 shows the characteristics of this device.

(Experimental Example 4) In Experimental Example 1, a hole injection layer was inserted between the anode and the light emitting region. That is, the device configuration shown in FIG. 8 was adopted. The hole injection layer was formed by spin coating using a commercially available polythiophene derivative before forming PVK, and the film thickness was 150 °. The ionization potential of the polythiophene derivative used here is 5.3 eV. Table 1 shows the characteristics of this device.

(Experimental Example 5) As the hole injection layer of Experimental Example 4, a commercially available polyaniline derivative having the same ionization potential as the above polythiophene derivative was used instead of the polythiophene derivative. The polyaniline derivative was formed in the same manner as in Experimental Example 2, and the film thickness was set to 150 °. Table 1 shows the characteristics of this device.

(Experimental Example 6) As the hole injection layer of Experimental Example 4, amorphous carbon was used instead of the polythiophene derivative. Amorphous carbon was formed by a sputtering method, and the film thickness was 100 °. The ionization potential of amorphous carbon is 5.2 eV. Table 1 shows the characteristics of this device.

(Experiment 7) In Experiment 1, an electron injection layer was inserted between the light emitting region and the cathode. That is, the device configuration shown in FIG. 9 was adopted. As the electron injection layer, dilithium phthalocyanine was used, and each light-emitting molecule was dropped on PVK, and then formed into a film by a vacuum evaporation method. Subsequently, an Al film was formed as a cathode. The electron injection layer and the cathode were formed by forming a film of dilithium phthalocyanine at 10 ° at a rate of about 0.3 ° / sec, and then forming Al at 1500 ° at a rate of about 30 ° / sec.
Å A film was formed. Dilithium phthalocyanine has an electron affinity of 3.0 eV. Table 1 shows the characteristics of this device.

(Experimental Example 8) As the electron injection layer of Experimental Example 7, instead of dilithium phthalocyanine, disodium phthalocyanine having the same electron affinity as this was used. The film formation of disodium phthalocyanine was performed in the same manner as in Experimental Example 7, and the film thickness was 10 °. Table 1 shows the characteristics of this device.

(Experimental Example 9) The electron injecting layer of Experimental Example 7 was replaced with 4,4,8,4 instead of dilithium phthalocyanine.
8-Tetrakis (1H-pyrazol-1-yl) pyrazaball was used. 4,4,8,8-tetrakis (1H-
Experimental Example 7 was used to form a pyrazol-1-yl) pyraza ball.
And the film thickness was 10 °. 4,4,8,8-
The electron affinity of tetrakis (1H-pyrazol-1-yl) pyrazaball is 2.3 eV. Table 1 shows the characteristics of this device.

(Experimental Example 10) In Experimental Example 3, instead of forming PVK as a polymer 3A, N, N'-diphenyl-N, N'-bis (3-methylphenyl) -1,1 'was used as a hole transporting material. PVK in which -biphenyl-4,4'-diamine (TPD) was dispersed was formed. That is, FIG.
Were produced. The ionization potential of TPD is 5.4 eV. The film was formed by PVK 300 mg and P
Using a solution in which 180 mg of BD was dissolved in 30 ml of a 1: 1 mixed solvent of toluene and chloroform, spin coating was performed under the same conditions as in Experimental Example 1. After the film formation, a mixed solution of each light emitting molecule and PBD was dropped as in Experimental Example 3.
Table 1 shows the characteristics of this device.

(Experimental Example 11) An organic light-emitting device was manufactured according to the process shown in FIG. After performing the steps up to FIG. 4C in the same manner as in Experimental Example 1, each luminescent molecule was permeated into the polymer 3A by a vapor treatment to form a luminescent region. The luminescent molecules were Nile Red, Coumarin 6, Coumarin 4 as in Experimental Example 1.
7 was used. Steam treatment was performed as follows. That is, first, of the striped anode 2 made of ITO, a mask having an opening only on the electrode for red is set on the substrate, and then a solution obtained by dissolving 10 mg of Nile Red in 10 ml of toluene is generated. Exposure to steam. further,
Heat treatment was performed at 110 ° C. for 1 minute using a hot plate. In this way, Nile Red was permeated into the desired positions. Subsequently, the mask was moved so that the opening was on the green electrode, and 10 mg of coumarin 6 was added to 10 ml of toluene.
Heat the solution dissolved in
Heat treatment was performed at 0 ° C. for 1 minute. Subsequently, after moving the mask in the same manner, steam treatment was performed using a solution in which 10 mg of coumarin 47 was dissolved in 10 ml of toluene, and heat treatment was performed at 110 ° C. for 1 minute. Finally, a Li / Al laminated electrode was formed as the cathode 24 by a vacuum deposition method in the same manner as in Experimental Example 1. Table 1 shows the characteristics of this device.

(Experimental Example 12) In Example 11, instead of forming PVK as the polymer 3A, 2- (4-
Biphenyl) -5- (4-tertbutylphenyl) -1,
PVK in which 3,4-oxadiazole (PBD) is dispersed
Was formed. The film is formed by PVK 300 mg and PBD 18
0 mg of a 30: 1 mixed solvent of toluene and chloroform.
Using a solution dissolved in ml, spin coating was performed under the same conditions as in Experimental Example 1. Table 1 shows the characteristics of this device.
Shown in

(Experimental Example 13) In Experimental Example 11, instead of performing the vapor treatment of the luminescent molecules, the vapor treatment was performed using a mixed solution of each luminescent molecule and PBD. That is, 1 mg of Nile Red + 100 mg of PBD, 1 mg of Coumarin 6 + P
BD100mg, 1mg coumarin 47 + PBD100
Using a solution obtained by dissolving mg in 30 ml of a mixed solvent of 1: 1 toluene and chloroform, steam treatment was performed on PVK. Table 1 shows the characteristics of this device.

(Experimental example 14) In Experimental example 1, instead of dropping the luminescent molecules, the luminescent molecules were permeated by the printing method. After a PVK film was formed on the substrate in the same process as in Experimental Example 1, a solution obtained by dissolving 1 mg of Nile Red in 10 ml of toluene was applied on a desired ITO electrode by a screen printing method, and then heated at 10 ° C. using a hot plate. For 1 minute. Similarly, Coumarin 6 and Coumarin 47 each 1
Using a solution prepared by dissolving mg in 10 ml of toluene, the solution was applied on a desired ITO electrode by screen printing, and heat-treated at 110 ° C. for 1 minute on a hot plate. Finally, a Li / Al laminated electrode was formed as the cathode 24 by a vacuum deposition method in the same manner as in Experimental Example 1. Table 1 shows the characteristics of this device.

(Experiment 15) In Experiment 14, instead of forming PVK as the polymer 3A, 2- (4-
Biphenyl) -5- (4-tertbutylphenyl) -1,
PVK in which 3,4-oxadiazole (PBD) is dispersed
Was formed. The film is formed by PVK 300 mg and PBD 18
0 mg of a 30: 1 mixed solvent of toluene and chloroform.
Using a solution dissolved in ml, spin coating was performed under the same conditions as in Experimental Example 1. Table 1 shows the characteristics of this device.
Shown in

(Experimental Example 16) In Experimental Example 14, instead of performing screen printing of luminescent molecules, each luminescent molecule was
Screen printing was performed using the mixed solution of D. That is,
1 mg of Nile Red + 100 mg of PBD, 1 mg of coumarin 6 + 100 mg of PBD, 1 mg of coumarin 47+
A solution obtained by dissolving 100 mg of PBD in 30 ml of a mixed solvent of toluene and chloroform at a ratio of 1: 1 was applied onto PVK by a screen printing method. Table 1 shows the characteristics of this device.

(Embodiment of Second Invention Group) Second Embodiment
The light-emitting element of the invention group has a light-emitting region between an anode and a cathode, the light-emitting region includes a substance that contributes to light emission, and between the anode and the cathode, a material that contributes to light emission. It is characterized by having a centralizing means for integrating the data into a specific area. More specifically, a light-emitting region is provided between the anode and the cathode, the light-emitting region contains a substance contributing to light emission, and a region that is made porous or roughened between the anode and the cathode. And a substance contributing to light emission is arranged on or near the surface of the porous region.

As described above, the presence of the porous or roughened region allows the substance contributing to light emission to a specific region (the surface of the porous or roughened region or the vicinity thereof). Since the surface area of the recombination region of holes and electrons, in which a substance contributing to light emission is present, is increased, high-luminance light emission can be realized.

[0205] By applying the light emitting element having the above structure to a display device or a lighting device, a display device or a lighting device having high luminance performance can be realized.

In Embodiment 2-1 described below, the structure of a light emitting element in which the light emitting region is made porous is described. In Embodiment 2-2, the structure in which the light emitting region is roughened is described.
No.-3 specifically describes a configuration in which the charge transport region is made porous or roughened.

[Embodiment 2-1] FIG. 15 is a schematic sectional view of an organic light emitting device according to Embodiment 2-1 of the present invention. As shown in FIG. 15, the organic light emitting device 100 includes an anode 105 formed on a substrate (not shown) and the anode 1
A light-emitting region 109 disposed between the anode 101 and the cathode 101;
The structure includes a flattening layer 102 disposed between the cathode 101 and the light emitting region 109.

The light emitting region 109 includes an organic layer 104 having the cathode 101 side made porous, and light emitting molecules 103 arranged on the porous surface of the organic layer 104.

Further, a flattening layer 102 made of a charge transporting substance is formed on the organic layer 104, and the cathode 101 is laminated on the flattening layer 102.

As described above, the light-emitting molecules 103 are
By concentrating on the surface of the organic layer 104 whose surface area has been increased by making it porous, and by making the hole-electron recombination region where the light-emitting molecules 103 are present porous, and increasing the surface area, high-luminance light emission can be achieved. Can be realized. Further, by providing a flattening layer 102 made of a charge-transporting substance on the surface of the porous organic layer 104, a bonding surface with an adjacent electrode (cathode 101) is kept smooth,
It is possible to prevent leakage current and efficiently inject and transport holes or electrons.

[0211] By injecting a charge-transporting substance into the porous portion of the organic layer 104, holes or electrons can be injected and transported efficiently.

The luminescent molecule 103 includes coumarin 6
Dyes having a quantum efficiency close to 1 such as laser dyes such as chromium, DCM, and phenoxazone 9 are preferred. In addition, condensed rings such as naphthalene, anthracene, pyrene, and naphthacene and derivatives thereof are also preferable. For example, rubrene is also a light emitting material having a quantum efficiency close to unity. In addition, the above Alq
And derivatives thereof and metal complexes such as beryllium benzoquinoline are also preferred.

The charge transporting substance that fills the porous interior of the organic layer 104 or forms the planarization layer 102 has a polarity opposite to that of the charge transported by the organic layer 104 to be porous. Need to transport charge.

When the organic layer 104 to be made porous is formed as a hole-transporting organic layer, an electron-transporting material is selected as the charge-transporting substance. In such a case, a hole transport material is selected as the charge transport material.

As the electron transporting material, a low molecular material which easily enters the inside of the porous material is preferable, and Alq, tris (4-
Metal complexes such as methyl-8-quinolinolato) aluminum; electron-deficient compounds such as 4,4,8,8-tetrakis (1H-pyrazol-1-yl) pyrazabole; 3- (2
'-Benzothiazolyl) -7-diethylaminocoumarin and the like are preferred. Further, materials having a hole blocking function, such as bathocuproine and triazole derivatives, are also preferable.

As the hole transporting material, a derivative having triphenylamine as a basic skeleton is preferable. For example, tetraphenylbenzidine compounds, triphenylamine trimers and benzidine dimers described in JP-A-7-126615, various triphenyldiamine derivatives described in JP-A-8-48656, JP-A-7-6595
No. 8 is preferable.

When filling the inside of the porous material, the material can be replaced with a charge injection material.

As the electron injection material, Japanese Patent Application No. 11-21 / 1999
No. 4712, dilithium phthalocyanine, disodium phthalocyanine, magnesium porphine,
4,4,8,8-tetrakis (1H-pyrazole-1-
Il) Pilaza balls and the like are preferred. As the hole injecting material, copper phthalocyanine, 5,10,15,20-tetraphenyl-21H, 23H-porphine copper, or the like is preferable (in Embodiment 2-2 described later, the roughened surface is smoothed). Even when the thickness is reduced to about 10 nm, a charge injection material can be used.

As the material to be filled into the inside of the porous material, a high molecular material can be selected in addition to the above low molecular material. However, there is a possibility that the material cannot be sufficiently filled only by coating. (E.g., in Embodiment 2-2 described later,
A polymer material can also be selected when filling a roughened surface).

As a material for forming the organic layer 104, an organic polymer is preferable in consideration of making the material porous. In particular, in the case where the surface is made porous, a high molecular weight organic compound is selected because it is wet-etched. Molecules are preferred).

Examples of the organic polymer constituting the organic layer include poly-p-phenylene vinylene (PPV), polyvinyl carbazole (PVK), and polymethyl methacrylate (P
General-purpose materials such as MMA), polyfluorene, and derivatives thereof can be used. Further, for the purpose of improving the charge transporting property, an electron transporting material or a hole transporting material may be mixed, and a general-purpose material as described above can be used.

The thickness of the organic layer is preferably from 10 to 1000 nm. The area to be made porous is preferably about 1/3 or less of the total thickness of the organic layer, particularly 5 to 50.
nm is preferred. That is, when the thickness of the organic layer is reduced to 10 nm or less, short-circuit occurs when a voltage is applied, and when the thickness is 1000 nm or more, the applied voltage increases,
This is because the luminous efficiency also decreases. The area to be made porous is about 1/3 of the entire organic layer or 50 nm.
In the case described above, the density of the organic layer is reduced, so that the charge transporting performance is reduced, and the rigidity of the film and the adhesion to the substrate are weakened. Further, when the porous region is 5 nm or less, the above-described effects are hardly obtained. (Note that Embodiment 2 described later)
2, the region to be roughened is the same as above.)
In the coating type organic layer, first, it is necessary to form a uniform film from the viewpoint of charge injection and transport. An organic polymer film is sparse when viewed microscopically, but a uniform film here is a macroscopic one, and the surface formed must have a surface roughness of at least 5 nm. is there.
Making the organic polymer film porous or roughened means further increasing the surface roughness of the uniformly formed film.

Next, a method for manufacturing an organic light emitting device will be described.
This will be described with reference to FIG. FIG. 16 is a schematic cross-sectional view illustrating the method for manufacturing the organic light-emitting device according to Embodiment 2-1 of the present invention.

(1) First, as shown in FIG.
The anode 105 was formed on the substrate 106 (anode forming step).

(2) Next, as shown in FIG.
A medium 104 ′ was disposed on the substrate 106. Note that the medium 104 'means a coating film obtained by applying a solution obtained by dissolving two types of organic polymer and an organic material that can be eluted for making the porous material into a solvent ( Medium placement step).

(3) Next, as shown in FIG.
The medium 104 ′ was dried by heating or air drying, and the medium 104 ′ was treated with a solvent in which the organic polymer was insoluble and only the organic material was soluble, to elute only the organic material. Then, the organic polymer layer was made porous by hollowing out the portion where the organic material was present, thereby forming the organic layer 104 (porousization step).

In the above-mentioned step of making porous, the organic layer 1
04, more specifically, the organic layer 1
At least one of the anode side 105 side and the cathode side 101 side of 04 may be made porous.

(4) Next, as shown in FIG.
On the organic layer 104, the light emitting molecules 103 were dispersed and arranged (light emitting molecule arrangement step).

(5) Next, as shown in FIG.
A flattening layer 102 made of a charge transporting material was formed on the organic layer 104 (flattening layer forming step).

(6) Then, as shown in FIG. 16F, a cathode 101 was formed on the flattening layer 102 (a cathode forming step).

The method for making the organic layer 104 porous is not limited to the method utilizing the difference in solubility as in the above method. For example, there are a method of insolubilizing an organic polymer by curing with ultraviolet irradiation, and a method of curing and insolubilizing by heat treatment.

The ratio of the organic material mixed with the organic polymer is preferably from 10 to 50%. When the proportion of the organic material is less than 10%, the film (organic layer) cannot be made sufficiently porous. When the proportion is more than 50%, the density of the film decreases, and the charge transport performance of the entire film decreases. Or the rigidity or adhesion to the substrate is weakened. Further, the ratio of the organic material is preferably 20 to 30%.

As the organic material to be selected, besides an organic polymer, an oligomer or the like having a reduced molecular weight so that the selection of a solvent can be widened can be used.

For the dispersion of the luminescent molecules, a vapor deposition method is preferable. It is also possible to form a solution and perform steam treatment. As a method of permeating the inside of the porous organic layer,
After the light emitting molecule dispersion, it is preferable to perform a vapor treatment (in addition,
Also in the embodiment 2-2 described below, it is preferable to perform the vapor treatment after the emission molecule dispersion.)

The organic light emitting element can emit surface light by making at least one electrode transparent or translucent. Usually, an ITO (indium tin oxide) film is often used for an anode serving as a hole injection electrode. Other examples include tin oxide, Ni, Au, Pt, and Pd. For the purpose of improving the transparency or reducing the resistivity of the ITO film, a film forming method such as sputtering, electron beam evaporation, or ion plating is employed.

The film thickness is determined from the required sheet resistance value and visible light transmittance. However, since the driving current density is relatively high in the organic light emitting device, the thickness is more than 100 nm in order to reduce the sheet resistance value. It is often used by the way.

The cathode as an electron injection electrode has Tang
The proposed MgAg alloy or AlLi alloy,
In many cases, an alloy of a metal having a low work function and a low electron injection barrier and a metal having a relatively large work function and being stable is used. Further, a metal having a low work function may be formed on the organic layer side, and a metal having a large work function may be thickly laminated for the purpose of protecting the metal having a low work function, such as Li / Al or LiF / Al.
Such a laminated electrode can be used. For forming these cathodes, a vapor deposition method or a sputtering method is preferable. When an electron injecting material such as dilithium phthalocyanine, disodium phthalocyanine, magnesium porphine, 4,4,8,8-tetrakis (1H-pyrazol-1-yl) pyraza ball is used, only a metal having a large and stable work function is used. Since the electrodes can be formed, the electrodes are less susceptible to reactions such as oxidation, and the life characteristics can be improved.

The substrate may be any as long as it can support the organic light-emitting element in which the above-mentioned thin films are stacked, and may be any transparent or translucent material so as to extract the light generated in the organic layer. Glass or polyester or other resin film.

FIG. 17 shows Embodiment 2 of the present invention.
FIG. 4 is a schematic cross-sectional view showing a modification of the organic light emitting device according to No. 1.

As shown in FIG. 17, the organic light emitting device 107
Is a structure in which light-emitting molecules 103, which are substances contributing to light emission, penetrate into the vicinity of the porous surface of the organic layer 104. The light-emitting molecules 103 can be permeated into the vicinity of the porous surface of the organic layer 104 by vapor treatment.

With such a structure, the light-emitting molecules 103 can be concentrated in the vicinity of the surface of the porous organic layer 104. Since the surface area of the recombination region with electrons is increased, high-brightness light emission can be realized. Further, the luminescent molecules may be arranged on both the surface of the organic layer 104 and near the surface.

(Experimental example 2-1) Experimental example 2-1 shows a specific example of the organic light emitting device of the embodiment 2-1. This will be described below.

Polyvinylcarbazole and butyral resin having a low degree of polymerization (Eslec B, manufactured by Sekisui Chemical Co., Ltd.)
(Product number BL-S) was dissolved in toluene at a weight ratio of 80:20 to obtain a solution.

Next, the above solution was spin-coated on a glass substrate on which ITO was formed to obtain an organic layer having a thickness of 100 nm.

The ITO substrate on which the organic layer was formed was immersed in N, N-dimethylformamide to dissolve and remove only the butyral resin (S-lec B), and then heated and dried at 200 ° C. to obtain a porous organic layer. Was.

After the temperature was returned to room temperature in the vacuum chamber, laser dye coumarin 6 was dispersed as a luminescent molecule at a deposition rate of 0.01 nm / s for 10 seconds by a vacuum deposition method using resistance heating.

Subsequently, 4,4,4
8,8-Tetrakis (1H-pyrazol-1-yl) pyraza ball was deposited at a deposition rate of 0.1 nm / s for 1 minute.

Finally, an Al electrode was formed at a deposition rate of 1 nm / s to a film thickness of about 100 nm to obtain an organic light emitting device.

Observation of the cross section of this device by SEM confirmed that a porous film having a diameter of about 3 to 6 nm was formed, and the porous portion was filled with an electron injection material. When a DC voltage was applied to the device and the device was evaluated, green light emission of coumarin 6 was obtained, and as shown in Table 2, the current efficiency was 8.0 cd / A, and the device continued to emit light stably.

[Table 2]

(Experimental Example 2-2) The organic light-emitting device of Experimental Example 2-2 was obtained by vapor deposition of the electron injection material of Experimental Example 2-1.
For the purpose of providing a flattening layer instead of filling the inside of the porous material, 4,4,8,8-tetrakis (1H-pyrazol-1-yl) pyraza ball was deposited at a deposition rate of 0.1 nm / s for 2 minutes. A planarization layer was obtained. Except for this, it was produced in the same manner as in Experimental Example 2-1.

When a cross section of the device was observed with an SEM, it was confirmed that a flattening layer was formed on a porous film having a diameter of about 3 to 6 nm. When a DC voltage was applied to the device for evaluation, coumarin 6 emitted green light. Further, as shown in Table 2, the current efficiency was 8.2 cd /
At A, it continued to glow stably.

(Experimental Example 2-4) Experimental Example 2-4 is for comparison with Experimental Examples 2-1 and 2-2 (a configuration in which the organic layer is not made porous).

That is, polyvinyl carbazole and 2- (4-biphenylyl) -5- (4-t
-Butylphenyl) -1,3,4-oxadiazole and coumarin 6 as a luminescent molecular material in a weight ratio of 100: 4.
It was dissolved in a mixed solvent of toluene and THF at a ratio of 0: 0.2 to obtain a solution.

Thereafter, the above solution was applied on a glass substrate on which ITO was formed by a spinner to form an organic layer having a thickness of 100 nm.

On this, 1 nm of Li was used as an electron injection electrode.
And a cathode made of Al having a thickness of 100 nm to obtain an organic light emitting device.

The device was evaluated by applying a DC voltage. As a result, coumarin 6 emitted green light. As shown in Table 2, the current efficiency was 3.2 cd / A.

Thus, the current efficiency of the organic light-emitting device having the porous organic layer was remarkably improved as compared with the case where the organic layer was not made porous.

[Embodiment 2-2] Embodiment 2-2
The present invention relates to an organic light emitting device having a structure in which a light emitting region is roughened. FIG. 18 is a schematic sectional view of an organic light emitting device according to Embodiment 2-2 of the present invention.

As shown in FIG. 18, the organic light emitting device 110
A light emitting region 113 disposed between the anode 105 and the cathode 101; a light emitting region 113 disposed between the anode 105 and the cathode 101; and a light emitting region 113 disposed between the anode 105 and the light emitting region 113. And a flattening layer 102 formed.

The light emitting region 113 includes an organic layer 120 whose surface on the side of the cathode 101 is roughened, and light emitting molecules 103 arranged on the roughened surface of the organic layer 120.

Further, a flattening layer 102 made of a charge transporting substance is formed on the organic layer 120, and the cathode 101 is laminated on the flattening layer 102.

As described above, the light emitting molecules 103 are concentrated in the light emitting region 113 (the surface of the organic layer 120) whose surface area is increased by roughening, and the recombination of holes and electrons where the light emitting molecules 103 are present. By roughening the region and increasing the surface area, high-brightness light emission can be realized. Note that, similarly to the case of Embodiment 2-1 described above, a configuration may be employed in which light-emitting molecules are penetrated near the surface of the organic layer, or light-emitting molecules may be disposed on both the surface and near the surface of the organic layer. Good.

Next, a method for manufacturing an organic light emitting device will be described with reference to FIG. FIG. 19 is a schematic sectional view illustrating the method for manufacturing the organic light emitting device according to Embodiment 2-2 of the present invention.

(1) The anode 105 is formed on the substrate 106 in the same manner as in the step (1) of the manufacturing method described in Embodiment 2-1.
Was formed (FIG. 19A).

(2) Next, a coating film 120 ′ as a medium is formed by an organic polymer forming an organic layer on the anode 105.
Was formed (FIG. 19B).

(3) Next, the coating film 120 'is subjected to reactive ion etching (RI)
E) dry etching is performed to form the coating film 12
The surface 0 ′ was roughened to form an organic layer 120 (FIG. 19).
(C)).

(4) Next, the light emitting molecules 103 are dispersed and arranged on the roughened surface of the organic layer 120 (FIG. 19).
(D)). The dry etching may be performed by a general-purpose type such as a barrel type or a parallel plate type, and depending on the state of the organic layer, Ar gas or the like may be simultaneously introduced.

(5) Next, a flattening layer 102 made of a charge-transporting substance was formed on the organic layer 120 in the same manner as in Embodiment 2-1 (FIG. 19E). (6) Next, the cathode 101 was formed on the flattening layer 102 (FIG. 19F). (Experimental example 2-3) Experimental example 2-3 is a modification of the above-described embodiment 2.
2 shows a specific example of the organic light-emitting device of No. 2. That is, a solution in which polyvinyl carbazole is dissolved in toluene is
Spin coating on glass substrate with TO
An organic layer of 0 nm was obtained.

Next, the ITO substrate on which the organic layer was formed was subjected to an oxygen flow rate of 60 seconds in a parallel plate type dry etching apparatus.
After performing a roughening treatment for 1 minute under the conditions of ccm, a pressure of 40 mTorr, and a high-frequency output of 100 W, it was placed in a vacuum chamber.

Next, a laser dye coumarin 6 was dispersed as a luminescent molecule at a deposition rate of 0.01 nm / s by a vacuum deposition method using resistance heating for 10 seconds.

Subsequently, 4,4,4 were used as electron injection materials.
8,8-Tetrakis (1H-pyrazol-1-yl) pyraza ball was deposited at a deposition rate of 0.1 nm / s for 2 minutes.

Finally, an Al electrode was formed at a deposition rate of 1 nm / s to a thickness of about 100 nm to obtain an organic light emitting device.

When the cross section of this device was observed with an SEM, it was confirmed that a rough surface of about ± 3 nm was formed on the organic layer, and that a flattening layer made of an electron injection material was formed. When a DC voltage was applied to the device for evaluation, coumarin 6 emitted green light. Further, as shown in Table 2 above, the current efficiency was 7.5 cd / A, and the light emission continued stably.

As described above, in the organic light-emitting device shown in Experimental Example 2-3, the organic layer was roughened, whereby
As compared with the organic light emitting device shown in FIG.

[Embodiment 2-3] Embodiment 2 above
The organic light-emitting devices of Nos. 1 and 2-2 have improved light-emitting efficiency by making the light-emitting region porous or roughened, but in Embodiment 2-3, the charge transport region is roughened. An organic light emitting device having a planarized structure will be described. FIG.
FIG. 3 is a schematic sectional view of an organic light emitting device according to Embodiment 2-3 of the present invention.

As shown in FIG. 20, the organic light emitting device 115
A light emitting region 117 disposed between the anode 105, the cathode 101, the light emitting region 117 disposed between the anode 105 and the cathode 101, and a light emitting region 117 disposed between the light emitting region 117 and the anode 105. Charge transport layer 116 provided.

The light emitting region 11 of the charge transport layer 116
The surface 7 is roughened by dry etching.
In the above configuration, the charge transport layer 116 is a hole transport layer.

With such a configuration, the contact area between the light emitting region 117 and the charge transport region 116 is improved, and the injection efficiency of holes injected from the anode 105 into the light emitting region 117 is improved.

In this embodiment, the structure in which the charge transport region is roughened has been described. However, by making the charge transport region porous, the same effect as in the case where the surface is roughened can be achieved. Of course, you can do that. Also,
When the charge transport layer 116 has light emission characteristics, the light emitting region 117 is not always necessary, and at least one of the charge transport layer 116 on the anode 105 side or the cathode 101 side is made porous or roughened. By doing so, the efficiency of charge injection from the electrodes is improved in the same manner as described above.

[0280]

As described above, according to the structure of the present invention, the object of the present invention can be sufficiently achieved.

That is, according to the invention of the first invention group, the luminescent molecules or the luminescent molecules and the charge transport material are impregnated into the polymer or the polymer in which the charge transport material is dispersed, so that the polymer-dispersed organic light-emitting device can be obtained. In addition, it is possible to provide an organic light-emitting device that can achieve high luminous efficiency and can be easily patterned.

Further, according to the invention group of the second invention group, in the polymer-based organic light-emitting device, the light-emitting region, which has conventionally been diffused throughout the organic layer, is concentrated into a specific region, and the hole in which the light-emitting molecule exists is formed. High-luminance light emission can be realized by increasing the surface area by making the recombination region of electrons and electrons porous or roughened.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an organic light emitting device according to Embodiment 1-1 of the present invention.

FIGS. 2A and 2B are schematic diagrams illustrating a configuration of an organic light emitting device according to Embodiment 1-2 of the present invention. FIG. 2A is a schematic conceptual diagram of the organic light emitting device, and FIG. It is sectional drawing in the AA line of a).

FIG. 3 is a schematic cross-sectional view illustrating a method for manufacturing an organic light-emitting device according to Embodiment 1-2 of the present invention.

FIG. 4 is a schematic sectional view showing another example of the method for manufacturing the organic light emitting device according to Embodiment 1-2 of the present invention.

FIG. 5 is a schematic diagram for explaining a concentration distribution in a light emitting region of the organic light emitting device according to Embodiment 1-2 of the present invention.

FIG. 6 is a schematic sectional view of an organic light emitting device according to Embodiment 1-3 of the present invention.

FIG. 7 is a schematic sectional view of an organic light emitting device according to Embodiment 1-4 of the present invention.

FIG. 8 is a schematic sectional view of an organic light emitting device according to Embodiment 1-5 of the present invention.

FIG. 9 is a schematic cross-sectional view showing another example of the organic light emitting device according to Embodiment 1-5 of the present invention.

FIG. 10 is a schematic sectional view showing another example of the organic light emitting device according to Embodiment 1-5 of the present invention.

FIG. 11 is an energy diagram of the organic light emitting device according to Embodiment 1-5 of the present invention.

FIG. 12 is an energy diagram of the organic light emitting device according to Embodiment 1-5 of the present invention.

FIG. 13 is an energy diagram of the organic light emitting device according to Embodiment 1-5 of the present invention.

FIG. 14 is an energy diagram of the organic light emitting device according to Embodiment 1-5 of the present invention.

FIG. 15 is a schematic sectional view of an organic light emitting device according to Embodiment 2-1 of the present invention.

FIG. 16 is a schematic sectional view showing the method for manufacturing the organic light emitting device according to Embodiment 2-1 of the present invention.

FIG. 17 is a schematic sectional view showing a modification of the organic light emitting device according to Embodiment 2-1 of the present invention.

FIG. 18 is a schematic sectional view of an organic light emitting device according to Embodiment 2-2 of the present invention.

FIG. 19 is a schematic sectional view showing the method for manufacturing the organic light emitting device according to Embodiment 2-2 of the present invention.

FIG. 20 is a schematic sectional view of an organic light-emitting device according to Embodiment 2-3 of the present invention.

[Explanation of symbols]

 Reference Signs List 1 substrate 2 anode 3 light emitting region 3A polymer 3F charge transporting substance 3G light emitting molecule 4 cathode 8 mask 10 organic light emitting device 20 organic light emitting device 21 substrate 22 anode 23 light emitting region 24 cathode 23A polymer 23R light emitting molecule (red) 23G light emitting molecule ( Green) 23B Light-emitting molecule (blue) 23E Charge-transporting substance 23H Hole-transporting material 23I Electron-transporting material 25 Hole injection layer 26 Electron injection layer 27 Ink head 100 Organic light emitting device 101 Cathode 102 Flattening layer 103 Light emitting molecule 104 Organic layer 104 'medium 105 anode 106 substrate 107 organic light emitting device 109 light emitting region 110 organic light emitting device 113 light emitting region 115 organic light emitting device 116 charge transport layer 117 light emitting region 120 organic layer 120' coating film

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Tetsuya Sato 1006 Kazuma Kadoma, Kadoma-shi, Osaka Matsushita Electric Industrial Co., Ltd. F-term (reference) 3K007 AB02 AB03 AB04 AB06 AB18 BA06 CA01 CB01 DA01 DB03 EA00 EB00 FA01

Claims (62)

[Claims] 1. A light-emitting element having a light-emitting region between an anode and a cathode, wherein the light-emitting region is composed of a substance contributing to light emission and a medium for containing the substance, and contributes to the light emission. A light-emitting element, wherein the substance has a concentration distribution substantially continuously from the anode side to the cathode side of the light-emitting region. 2. The substance that contributes to light emission has a concentration distribution such that one of the anode side and the cathode side of the light emitting region has a higher concentration than the other side, and 2. The light emitting device according to claim 1, wherein the concentration is continuously reduced toward the side. 3. The light emitting device according to claim 1, wherein the light emitting region further includes a charge transporting substance. 4. The light emitting device according to claim 3, wherein the charge transporting substance has a concentration distribution substantially continuously from the anode side to the cathode side of the light emitting region. element. 5. A light emitting device having a charge transporting region between an anode and a cathode, wherein the charge transporting region comprises a charge transporting substance and a medium for containing the charge transporting substance, A light-emitting element, wherein the charge-transporting substance has a concentration distribution substantially continuously from the cathode side to the anode side of the charge-transporting region. 6. The light emitting region according to claim 1, wherein the light emitting region has a region in which a substance contributing to the light emission does not exist.
The light-emitting device according to claim 4. 7. The light emitting device according to claim 1, wherein a portion of the light emitting region which shows the maximum concentration of the substance contributing to light emission is apart from the anode and the cathode. element. 8. The charge transport region according to claim 5, wherein the charge transport region has a region where the charge transport material does not exist.
The light-emitting device according to item 1. 9. The light emitting device according to claim 5, wherein a portion of the charge transport region, which indicates the maximum concentration of the charge transporting substance, is apart from the anode and the cathode. 10. A lighting device using the light emitting device according to claim 1. Description: 11. A light-emitting element having a light-emitting region between an anode and a cathode, wherein the light-emitting region is composed of a substance contributing to light emission and a medium for containing the substance; A light-emitting element, wherein the concentration of the substance contributing to light emission in the direction parallel to the anode surface decreases substantially continuously from substantially the center to the periphery of the light-emitting region. 12. A structure having a plurality of substances contributing to light emission adjacent to each other in a direction parallel to the cathode surface and the anode surface, wherein the plurality of substances contributing to light emission have different emission colors. The light emitting device according to claim 11, wherein: 13. The light emitting region according to claim 11, further comprising a charge transporting substance.
The light-emitting device according to item 1. 14. The charge transporting substance according to claim 13, wherein the concentration of the charge transporting substance decreases from substantially the center to the periphery of the light emitting region in a direction parallel to the cathode surface and the anode surface. Light emitting element. 15. The substance that contributes to the light emission has a structure that has a concentration distribution substantially continuously from the cathode side to the anode side of the light emitting region.
The light emitting device according to claim 14. 16. The luminescence according to claim 14, wherein said charge transporting substance has a concentration distribution substantially continuously from said cathode side to said anode side of said light emitting region. element. 17. The light emitting device according to claim 11, wherein the light emitting region has a region where a substance contributing to the light emission does not exist. 18. The light emitting device according to claim 11, wherein the light emitting region has a charge transporting performance. 19. The light emitting device according to claim 11, wherein the light emitting region is made of an organic material. 20. The light emitting device according to claim 11, wherein the light emitting region is made of a polymer. 21. A display device using the light emitting device according to claim 11. Description: 22. A method for manufacturing a light-emitting element having a light-emitting region between an anode and a cathode, comprising: a disposing step of disposing a medium on the anode or the cathode; and a substance contributing to light emission in the medium. And a forming step of forming a light emitting region. 23. A method for manufacturing a light-emitting element having a light-emitting region between an anode and a cathode, comprising: a step of arranging a medium containing a charge transporting substance on the anode or the cathode; A production step of forming a light-emitting region by containing a substance that contributes to light emission. 24. A method for manufacturing a light-emitting element having a light-emitting region between an anode and a cathode, comprising: arranging a medium on the anode or the cathode; and a substance and a charge contributing to light emission in the medium. A method for producing a light emitting element, comprising: a step of containing a transportable substance. 25. A method for manufacturing a light-emitting device having a light-emitting region between an anode and a cathode, the method comprising: arranging a medium containing a charge-transporting substance on the anode or the cathode; A method for manufacturing a light-emitting element, comprising: a step of containing a substance contributing to light emission and a charge-transporting substance. 26. A method for manufacturing a light emitting device having a charge transporting region between an anode and a cathode, comprising: arranging a medium on the anode or the cathode; and containing a charge transporting substance in the medium. Containing step to be performed,
A method for manufacturing a light emitting device, comprising: 27. The method for manufacturing a light emitting device according to claim 22, wherein in the containing step, the substance contributing to light emission is contained by being penetrated into the medium. 28. The method according to claim 2, wherein in the containing step, the substance contributing to light emission and the charge transporting substance are contained by penetrating into a medium.
5. The method for manufacturing a light emitting device according to item 4. 29. The method according to claim 22, wherein, in the containing step, a solution obtained by dissolving the substance contributing to luminescence in a solvent is permeated by contact with the medium. A method for manufacturing a light emitting device. 30. The method according to claim 24, wherein in the containing step, a solution obtained by dissolving the substance contributing to light emission and the charge transporting substance in a solvent is permeated by contact with the medium. 3. The method for manufacturing a light emitting device according to item 1. 31. The method for manufacturing a light emitting device according to claim 22, wherein in the containing step, a substance contributing to light emission is permeated into the medium by an ink jet method. 32. A light-emitting element having a light-emitting region between an anode and a cathode, wherein the light-emitting region contains a substance that contributes to light emission, and between the anode and the cathode, contributes to the light emission. A light-emitting element having a consolidating means for consolidating a substance into a specific region. 33. A light emitting element having a light emitting region between an anode and a cathode, wherein at least one of the anode side and the cathode side of the light emitting region is made porous, and the light emitting region is made porous. A light-emitting element having a structure having a substance contributing to light emission on a surface provided. 34. A light emitting device having a light emitting region between an anode and a cathode, wherein at least one of the light emitting region on the anode side or the cathode side is made porous, and the light emitting region is made porous. A light-emitting element having a substance that contributes to light emission in the vicinity of the surface of the light-emitting element. 35. The light-emitting device according to claim 33, wherein the light-emitting region has a structure in which a charge-transporting substance is provided on a porous surface of the light-emitting region. 36. The light emitting device according to claim 33, wherein the light emitting device has a structure in which a flattening layer made of a charge transporting substance is provided on the porous surface of the light emitting region. 37. A light-emitting device having a charge transport region between an anode and a cathode, wherein at least one of the charge transport region on the anode side or the cathode side is made porous. Light emitting element. 38. The light emitting device according to claim 37, wherein the charge transport region is a hole transport region. 39. The light emitting device according to claim 37, wherein the charge transport region is an electron transport region. 40. The light emitting device according to claim 33, wherein the light emitting region is made of an organic material. 41. The light emitting device according to claim 33, wherein the light emitting region is made of a polymer. 42. A light emitting element having a light emitting region between an anode and a cathode, wherein at least one of the light emitting region on the anode side or the cathode side is roughened, and the light emitting region is roughened. A light-emitting element having a structure having a substance contributing to light emission on a surface provided. 43. A light emitting element having a light emitting region between an anode and a cathode, wherein at least one of the light emitting region on the anode side or the cathode side is roughened, and the light emitting region is roughened. A light-emitting element having a substance that contributes to light emission in the vicinity of the surface of the light-emitting element. 44. The roughened surface of the light emitting region,
44. The light emitting device according to claim 42, further comprising a flattening layer made of a charge transporting substance. 45. A light emitting device having a charge transport region between an anode and a cathode, wherein at least one of the charge transport region on the anode side or the cathode side is roughened. Light emitting element. 46. The light emitting device according to claim 45, wherein the charge transport region is a hole transport region. 47. The light emitting device according to claim 45, wherein the charge transport region is an electron transport region. 48. The light emitting device according to claim 42, wherein said light emitting region is made of an organic material. 49. The light emitting device according to claim 42, wherein said light emitting region is made of a polymer. 50. A display device using the light emitting element according to claim 32. 51. A lighting device using the light emitting device according to claim 32. 52. A method for manufacturing a light emitting device having a light emitting region between an anode and a cathode, comprising: a medium arranging step of arranging a medium on the anode or the cathode; A method of manufacturing a light emitting device, comprising: 53. A method for manufacturing a light emitting device having a light emitting region between an anode and a cathode, comprising: a medium arranging step of arranging a medium on the anode or the cathode; A step of making at least one of them porous, and a substance that contributes to light emission is arranged on the porous surface of the medium, and a light emitting region is formed by the medium and the substance that contributes to light emission. And a disposing step. 54. A method for manufacturing a light emitting device having a light emitting region between an anode and a cathode, comprising: a medium arranging step of arranging a medium on the anode or the cathode; A step of making at least one of them porous, and a material that contributes to light emission is contained in the vicinity of the porous surface of the medium, and a light emitting region is formed by the medium and the material that contributes to light emission. And a disposing step of disposing a charge-transporting substance on the porous surface of the light-emitting region. 55. The method for manufacturing a light emitting device according to claim 53, further comprising an arrangement step of arranging a charge transporting substance on the porous surface of the light emitting region. 56. The method according to claim 53, further comprising a flattening layer forming step of forming a flattening layer made of a charge transporting material on the light emitting region. . 57. The medium arranging step is a step of arranging a medium containing a substance soluble in a specific solvent. The porous forming step is performed by eluting the substance with the solvent. 55. The method for manufacturing a light emitting device according to claim 53, wherein the step is performed. 58. A method for manufacturing a light emitting device having a light emitting region between an anode and a cathode, comprising: a medium arranging step of arranging a medium on the anode or the cathode; and roughening a part of the medium. A method of manufacturing a light emitting device, comprising: 59. A method for manufacturing a light emitting device having a light emitting region between an anode and a cathode, comprising: a medium arranging step of arranging a medium on the anode or the cathode; A roughening step of roughening at least one of them, an arrangement step of arranging a substance contributing to light emission on the rough surface of the medium, and forming a light emitting region with the medium and the substance contributing to light emission, A method for manufacturing a light emitting device, comprising: 60. A method for manufacturing a light emitting device having a light emitting region between an anode and a cathode, comprising: a medium arranging step of arranging a medium on the anode or the cathode; A roughening step of roughening at least one of them, and a containing step of forming a light emitting region with the medium and the material contributing to light emission, in the vicinity of the rough surface of the medium, containing a substance contributing to light emission. A method for manufacturing a light emitting device, comprising: 61. The method of manufacturing a light emitting device according to claim 59, further comprising a flattening layer forming step of forming a flattening layer made of a charge transporting material on the light emitting region. . 62. The method according to claim 59, wherein the roughening step is a step of roughening the light emitting region by dry etching.