JP2022116901A - Organic electroluminescence element and manufacturing method thereof, and lighting device, display device, and printed product including the same - Google Patents

Abstract

To provide an organic electroluminescence element having high luminous efficiency, a long life, and suppressed deterioration in a performance during manufacturing in the atmosphere, a manufacturing method thereof, and a lighting device, a display device, and a printed product equipped with the organic electroluminescence element.SOLUTION: In an organic electroluminescence device having an image display portion sandwiched between an anode and a cathode facing each other on at least a substrate, the image display portion is constituted by a light-emitting image display portion and a non-light-emitting image display portion, the light-emitting image display portion includes at least a light-emitting layer adjacent to an electrode, a charge injection layer, or a charge transport layer, and the light-emitting layer contains a polymer having conductivity of 1 S/m or less, a charge-transporting host compound and a light-emitting dopant, and in the light-emitting layer, a polymer ratio satisfies a specific condition.SELECTED DRAWING: Figure 5

Description

TECHNICAL FIELD The present invention relates to an organic electroluminescence element, a method for manufacturing the same, and a lighting device, a display device, and a printed product having the same. It relates to an organic electroluminescence element and the like in which deterioration in performance is suppressed.

In recent years, from the viewpoint of thinning and weight reduction, which are in increasing demand, organic electroluminescent devices (or diodes), which are self-luminous and do not require a backlight, have attracted attention. are collecting. Organic electroluminescence elements not only enable such flexible displays and flexible lighting, but also have features such as wide viewing angles and excellent visibility, fast response speeds and excellent video playback performance, etc. commercialization is expected. For practical use, higher luminous efficiency, longer life, and lower manufacturing costs are required, and research and development are proceeding.

An organic electroluminescence device is a device using an organic light-emitting material that emits light when a voltage is applied. Specifically, by sandwiching an organic layer including a light-emitting layer between a cathode and an anode and applying a voltage, electrons and holes recombine in the light-emitting layer. An organic electroluminescence device utilizes light (electromagnetic waves) emitted when excitons (excitons) generated at this time are deactivated and return to the ground state.

The organic layer is a thin film, and methods for producing the thin film are roughly divided into a vapor deposition method and a wet method (also referred to as a “coating method”). Vapor deposition is a manufacturing method that mainly uses low-molecular-weight compounds as materials. In the vapor deposition method, there is a limit to the number of materials that can be mixed, so the materials must be changed for each layer and the layers must be laminated while separating the functions. there were. In addition, a shadow mask is used for color coding, and the material adheres to the mask, etc., so there is room for improvement in terms of low material utilization efficiency. Furthermore, from the viewpoint of precision, it is difficult to increase the size of the mask, making it extremely difficult to manufacture large products.

On the other hand, the wet method is being researched and developed from the viewpoint that it is possible to manufacture large products with a simple apparatus. In particular, it is possible to apply the printing technique to the wet method by using a polymer material exhibiting good solubility in a solvent as the ink.

For example, Non-Patent Document 1 discloses an example of an organic EL display device in which a multi-color pixel is realized by injecting a polymer light-emitting material into an insulating bank by an inkjet printing method. However, the manufacturing method of the display device, which is typified by the manufacturing of the organic EL display device (display), requires prior formation of banks and advanced alignment technology, and there is room for improvement in terms of process simplification and cost reduction. was there. In addition, it was not suitable for the production of a wide variety of products in small quantities accompanying the recent on-demand trend.

As a means suitable for manufacturing a wide variety of products in small quantities, Non-Patent Document 2 discloses an example in which dots with a diameter of 200 μm are patterned by an inkjet printing method without the need for bank formation in advance. Specifically, after spin-coating polymethyl methacrylate (PMMA) as an ink-receiving layer, a host compound and a light-emitting material are printed on the areas corresponding to the light-emitting image display areas, and printed on the areas corresponding to the non-light-emitting image display areas. In this method, only the ink-receiving layer is used. Phosphorescent compounds, for example, Ir(ppy) ₃ , which can be expected to have an external quantum efficiency of about 20%, are used as the light-emitting material. It remains to the extent and further improvement is required. Further, the inkjet printing method is a method that can be formed even in the air, but it is affected by the active gas in the film formation atmosphere, so there is a problem that the performance of the element is deteriorated.

In addition, in manufacturing using polymer materials, the materials between the layers are easily dissolved, and only a single layer or a small number of layers can be formed, and it is necessary to give many functions to these single layers or a small number of layers. , requires advanced molecular design.

Furthermore, production under a vacuum or inert gas environment, which has been conventionally used, requires equipment, so development of organic electroluminescence elements that can be produced under the atmosphere is underway. It is believed that the performance of the element deteriorates due to the reaction between the polymer material and the oxygen and moisture taken in during film formation in the production in the atmosphere, and further improvement is required.

T.Shimoda S.Kanbe, H.Kobayashi,S.Seki,H.Kiguchi,I.Yudasaka,M.Kimura,S.Miyashita, R.H.Friend, J.H.Burroughes, C.R.Towns: Multicolor Pixel Patterning of Light-Emitting Polymers by Ink-Jet Printing, SID99 Digest, 26.3, p.376 (1999) Ryuichi Satoh et al ; Self-Aligned Bank Formation of Organic Electroluminescent Devices Using Ink-Jet Printing Method; Jpn. J. Appl. Phys. 43, No. 11R, 7725 (2004)

The present invention has been made in view of the above problems and situations, and the problem to be solved is an organic electroluminescence device that has high luminous efficiency, has a long life, and suppresses deterioration in performance during production in the atmosphere. and a method for manufacturing the same, and a lighting device, a display device, and a printed product having the same.

In order to solve the above problems, the present inventors have investigated the causes of the above problems, and found that the light emitting layer formed in the light emitting image display section is composed of a relatively low-conductivity polymer, a charge-transporting host compound, and a light-emitting A dopant is contained, the polymer in the light-emitting layer is appropriately dispersed, and is appropriately localized in the central portion or near the interface on the electrode side, so that the light-emitting efficiency is high, the life is long, and the light-emitting layer can be used in the atmosphere. The present inventors have found that it is possible to provide an organic electroluminescence device in which deterioration in performance during production is suppressed, and have completed the present invention.
That is, the above problems related to the present invention are solved by the following means.

1. An organic electroluminescence element having an image display portion sandwiched between an anode and a cathode facing each other on at least a substrate,
wherein the image display section is composed of a luminescent image display section and a non-luminescent image display section,
The light-emitting image display section has at least a light-emitting layer adjacent to an electrode, a charge injection layer, or a charge transport layer,
the light-emitting layer contains a polymer having a conductivity of 1 S/m or less, a charge-transporting host compound, and a light-emitting dopant;
An organic electroluminescence device, wherein in the light-emitting layer, a polymer ratio P represented by the following formula (i) satisfies the following condition (ii).
(i) _P =IP/( _{IP +} IH+ _IDp )
(ii) At least either Pa/Pb or Pc/Pb is 0.8 or more and less than 2.2.
[Wherein, I _P , I _H and I _Dp are a polymer, a charge-transporting host compound, and a luminous is the secondary ion intensity of the dopant.
Pa is the polymer ratio near the interface on the anode side (x = (D-[D/10])),
Pb is the polymer ratio in the central part (x=D/2),
Pc is the polymer ratio near the cathode-side interface (x=D/10).
However, x indicates the position in the thickness direction in the light-emitting layer. The anode-side interface is represented by x=D. ]

2. 2. The organic electroluminescence device according to claim 1, wherein the polymer ratio P satisfies the following condition (iii).
(iii) At least one of Pa/Pb or Pc/Pb is 0.95 or more and less than 2.0

3. 3. The organic electroluminescence device according to claim 1 or 2, wherein the polymer ratio P satisfies the following condition (iv).
(iv) at least one of Pa/Pb or Pc/Pb is 1.1 or more and less than 1.8

4. 4. The organic electroluminescence device according to any one of items 1 to 3, wherein the polymer ratio P satisfies the condition (v).
(v) Pa≦Pc

5. 5. The organic electroluminescence device according to any one of items 1 to 4, wherein the polymer ratio P satisfies the condition (vi).
(vi) Pa<Pc

6. Any one of items 1 to 5, wherein in the light-emitting layer, the mass ratio of the polymer is in the range of 5 to 80% by mass when the total mass of the light-emitting layer is 100. The organic electroluminescence device according to Item 1.

7. 7. The organic electroluminescence device according to any one of items 1 to 6, wherein the polymer has a conductivity of 1E-8 S/m or less.

8. 8. The organic electroluminescence device according to any one of items 1 to 7, wherein the polymer is a polymer containing a benzene ring.

9. 9. The organic electroluminescence device according to any one of items 1 to 8, wherein the polymer is a polymer containing a benzene ring as a side chain.

10. 10. The organic electroluminescence device according to any one of items 1 to 9, wherein the polymer is polystyrene.

11. 10. The organic electroluminescence device according to any one of items 1 to 9, wherein the polymer is a polystyrene derivative.

12. 12. The organic electroluminescence device according to Item 11, wherein the polystyrene derivative is polyvinylphenol.

13. 13. The organic electroluminescence device according to any one of items 1 to 12, wherein the polymer is a mixture of components having different stereoregularities.

14. 14. The organic electroluminescence device according to any one of items 1 to 13, wherein the light emitting layer is directly adjacent to at least the electrode or the charge injection layer.

15. 15. The organic electroluminescence device according to any one of items 1 to 14, wherein the light-emitting layer is directly adjacent to an electrode.

16. A method for producing an organic electroluminescence device for producing the organic electroluminescence device according to any one of items 1 to 15,
A method for producing an organic electroluminescence device, comprising: forming the light-emitting layer by an inkjet printing method.

17. 17. The method for producing an organic electroluminescence element according to Item 16, further comprising a step of forming the light-emitting layer by an inkjet printing method in the atmosphere.

18. A lighting device comprising the organic electroluminescence element according to any one of items 1 to 15.

19. A display device comprising the organic electroluminescent element according to any one of items 1 to 15.

20. A printed modeled article comprising the organic electroluminescence element according to any one of items 1 to 15.

Organic electroluminescence device with high luminous efficiency, long life, and suppressed deterioration in performance during production in the atmosphere by the above-described means of the present invention, method for producing the same, and lighting device and display device equipped with the same and a printed model can be provided.

Although the expression mechanism or action mechanism of the effect of the present invention has not been clarified, it is speculated as follows.

In the present invention, the light-emitting layer formed in the light-emitting image display portion contains a polymer, a charge-transporting host compound, and a light-emitting dopant. Alternatively, it is presumed that the above problem could be solved by appropriately localizing in the vicinity of the interface on the electrode side.
The following explanation considers the effect expression mechanism obtained by controlling the polymer distribution ratio in the light-emitting layer, and is not necessarily clear. Therefore, the expression mechanism of the effect of the present invention is not limited to the speculated mechanism below.

The organic electroluminescence element of the present invention has an image display portion sandwiched between an anode and a cathode, and the image display portion is composed of a light emitting image display portion and a non-light emitting image display portion. The light-emitting image display section has a light-emitting layer, and may have an injection layer and a transport layer for electrons and holes, that is, charge carriers, in addition to the light-emitting layer. When a single layer or a small number of layers are preferred, the number of layers can be reduced by including a compound having charge carrier injecting and transporting properties in the light-emitting layer.

Non-Patent Document 2 discloses an example in which a chloroform solution in which a host compound and a light-emitting material are dissolved is printed on a portion corresponding to a light-emitting image display portion after applying polymethyl methacrylate (PMMA). The light-emitting layer in this example is formed by a mixture of a host compound, a light-emitting material, and PMMA. was in need of further improvement.

Therefore, as a result of further investigation, it was found that a single-layer structure can be obtained by appropriately dispersing a relatively low-conductivity polymer in the light-emitting layer and appropriately localizing it in the central portion or near the interface on the electrode side. To obtain an organic electroluminescence element that can exhibit carrier balance and block properties like those of a multilayer structure, has high luminous efficiency, has a long life, and is capable of suppressing deterioration in performance during production in the atmosphere. I found

Although the details of the mechanism of expression of this function have not yet been clarified, the following possibilities are presumed.

In order to increase the luminous efficiency, it is required to emit light with high probability and to remove factors that contribute to quenching. In order to emit light with a high probability, it is necessary to make recombination of electrons and holes more likely in the light-emitting layer, and it is preferable that the charge carriers can move freely. On the other hand, when electrons and holes cannot recombine and remain as accumulated charges, the chances of charged, unstable and activated chemical species to react with other chemical species and change increase, contributing to quenching. It is preferable that charge carrier balance is maintained and stored charge is suppressed, as it can generate factors.

Also, when the device is driven with a constant current, the brightness gradually decreases. This is called lifespan. In order to prolong the life, it is necessary to suppress the deterioration of the brightness of the light-emitting material itself, in addition to taking measures such as driving the display. Various causes are conceivable for the decrease in brightness, but it is conceivable that the luminescent material reacts with chemical species generated by driving the display or the like and changes. In particular, when driven by a constant current, electrons and holes cannot recombine and remain as accumulated charges, giving chances for charged, unstable and activated chemical species (e.g., ions and radicals) to react with the light-emitting material. increases. Therefore, from the viewpoint of life, it is preferable that the charge carrier balance is maintained.

In the light-emitting layer, the host compound serves as a path for the transport and movement of electrons and holes, that is, charge carriers, and also as a medium (matrix) that maintains the dispersed state of the light-emitting dopant. .

On the other hand, when a polymer with relatively low conductivity is contained in the light-emitting layer, the polymer exhibits blocking ability, and a host compound or a light-emitting dopant is present between the light-emitting layer and the adjacent layer or between the light-emitting layer and the electrode. limited migration of chemical species such as charge carriers and compounds to the Therefore, the charge carrier balance is easily maintained, and the occurrence of factors contributing to quenching is easily suppressed. In addition, by concentrating the polymer on the electrode-side interface as compared to the central portion of the light-emitting layer, the blocking ability works more effectively, so that a remarkable effect can be obtained.

In addition, materials used in organic electroluminescence elements may not exhibit their inherent functions if they react with oxygen or water, so production in the presence of oxygen or water is difficult. However, since the charge-transporting host compound and the light-emitting dopant according to the present invention enter into the gaps of the polymer, they are relatively difficult to come into contact with oxygen and water in the atmosphere during film formation in the atmosphere, and the reaction is suppressed. can be done.

The effect of the present invention is likely to be exhibited when the light-emitting layer is formed by a droplet discharge method such as inkjet. When the film is formed by the droplet discharge method, the effect of the active gas in the film formation atmosphere is more pronounced than when the film is formed by vapor deposition or spin coating, and it is more affected by a decrease in luminous efficiency and a shorter life. However, even in such a case, light is emitted without deterioration in performance. Therefore, manufacturing costs for inert gas and vacuum equipment can also be reduced.

FIG. 4 is a conceptual diagram showing that the image display section consists of a luminescent image display section and a non-luminescent image display section. Schematic cross-sectional view of the organic EL element of the present invention Cross-sectional view showing an example of a partition (bank) Schematic diagram showing an example of a single-pass system (line head system) inkjet recording apparatus applicable to the method for manufacturing an organic EL element of the present invention. Cross-sectional view of an organic EL element produced in Examples

The organic electroluminescence device of the present invention is an organic electroluminescence device having an image display portion sandwiched between an anode and a cathode facing each other on at least a substrate, wherein the image display portion comprises a light-emitting image display portion and a non-light-emitting image display portion. The light-emitting image display portion has at least a light-emitting layer adjacent to an electrode, a charge injection layer, or a charge transport layer, and the light-emitting layer is a polymer having a conductivity of 1 S/m or less and a charge transport property. The light-emitting layer contains a host compound and a light-emitting dopant, and the polymer ratio P represented by the formula (i) satisfies the condition (ii).
This feature is a technical feature common to or corresponding to the following embodiments.

As an embodiment of the present invention, at least one of Pa/Pb and Pc/Pb in the polymer ratio P is 0.8 or more and less than 2.2, from the viewpoint that the blocking ability of the polymer functions more effectively. It is preferably 0.95 or more and less than 2.0, more preferably 1.1 or more and less than 1.8.

In the polymer ratio P, the magnitude of Pa and Pc or the same relationship is not particularly limited. and more preferably Pa<Pc.

From the viewpoint that the blocking ability of the polymer functions more effectively, it is preferable that the mass ratio of the polymer is in the range of 5 to 80% by mass when the total mass of the light-emitting layer is 100.

From the viewpoint that the blocking ability of the polymer functions more effectively, the polymer preferably has a conductivity of 1E-8 S/m or less.

The polymer is preferably a polymer containing a benzene ring from the viewpoint of compatibility with the light-emitting layer material through interaction. Moreover, the polymer is preferably a polymer containing a benzene ring as a side chain.

Moreover, from the viewpoint of improving the density of the light-emitting layer, the polymer is preferably polystyrene or a polystyrene derivative. Furthermore, it is preferred that the polystyrene derivative is polyvinylphenol.

From the viewpoint of being able to control the polymer ratio at the interface of the light-emitting layer and adjust the charge carrier balance, the polymer is preferably a mixture of components with different stereoregularities.

From the viewpoint of being composed of a single layer or a small number of layers, the light-emitting layer is preferably directly adjacent to at least the electrode or the charge injection layer, and more preferably directly adjacent to the electrode.

The method for producing an organic electroluminescence element of the present invention is characterized by including the step of forming the light-emitting layer by an inkjet printing method. Moreover, it is more preferable to have a step of forming the light-emitting layer by an inkjet printing method in the atmosphere.

The organic electroluminescence device of the present invention can be suitably used for lighting devices, display devices and printed objects.

DETAILED DESCRIPTION OF THE INVENTION The present invention, its constituent elements, and embodiments and modes for carrying out the present invention will be described in detail below. In the present application, "-" is used to mean that the numerical values before and after it are included as the lower limit and the upper limit.

1 <<Overview of the organic electroluminescence element of the present invention>>
The organic electroluminescence device of the present invention is an organic electroluminescence device having an image display portion sandwiched between an anode and a cathode facing each other on at least a substrate, wherein the image display portion comprises a light-emitting image display portion and a non-light-emitting image display portion. The light-emitting image display portion has a light-emitting layer adjacent to at least an electrode, a charge injection layer, or a charge transport layer, and the light-emitting layer is a polymer having a conductivity of 1 S/m or less and a charge transport property. The light-emitting layer contains a host compound and a light-emitting dopant, and is characterized in that the polymer ratio P represented by the following formula (i) satisfies the following condition (ii).

(i) _P =IP/( _{IP +} IH+ _IDp )
(ii) At least either Pa/Pb or Pc/Pb is 0.8 or more and less than 2.2.
[Wherein, I _P , I _H and I _Dp are a polymer, a charge-transporting host compound, and a luminous is the secondary ion intensity of the dopant.
Pa is the polymer ratio near the interface on the anode side (x = (D-[D/10])),
Pb is the polymer ratio in the central part (x=D/2),
Pc is the polymer ratio near the cathode-side interface (x=D/10).
However, x indicates the position in the thickness direction in the light-emitting layer. The anode-side interface is represented by x=D. ]

The "electrode-side interface of the light-emitting layer" as used in the present invention refers to the interface of the light-emitting layer that is on the electrode side of the light-emitting layer and is in contact with all functional layers including the anode or cathode. For example, when there is a "hole-transporting layer" adjacent to the anode side of the light-emitting layer, it means "the interface on the hole-transporting side of the light-emitting layer".

In addition, “near the interface on the electrode side of the light-emitting layer” means that “near the interface on the anode side” refers to the distance D/ It refers to a position that is 10 away (x=(D-[D/10]).
On the other hand, the “neighborhood of the cathode-side interface” is a position (x=D/10) separated from the interface (x=0) between the cathode and the light-emitting layer by a distance D/10 in the direction of the thickness of the light-emitting layer, that is, in the direction of the anode. ).

Although the organic EL element of the present invention can take various forms/structures, for example, as a method and form of extracting light, it is preferable to use a bottom emission type in which light is extracted from the substrate side. In the bottom emission type, an image is displayed when viewed from the substrate side, and the portion where the image is displayed (including planar and three-dimensional structures) is called an "image display section."

FIG. 1 is a conceptual diagram (plan view) of the image display unit 40 viewed from the viewing side. In FIG. 1 , the portion indicated by black dots is the “luminescence image display portion” 41 , and the other white portion is the “non-luminescence image display portion” 42 . For example, blue (B) light-emitting pixels 21, green (G) light-emitting pixels 22, and red (R) light-emitting pixels 23 are arranged in dots to draw lines and various figures made up of a plurality of dots. can be done.

In other words, when the light-emitting pixels are dot-shaped, for example, the “light-emitting image display portion” refers to individual dots themselves and aggregates thereof shown in FIG. The “light-emitting pixel” is a minimum element that expresses color information (color tone and gradation) by emitting light. Also, the "light-emitting pixels" are also referred to as "light-emitting dots", "dot light-emitting images", or simply "dots".
The "light-emitting image display section" according to the present invention includes elements such as a light-emitting layer that contributes to the manifestation of the light-emitting property of the light-emitting image display section when viewed from the cross-sectional view of the organic EL element. Specifically, it refers to the entire portion indicated by 41 in FIG.

A “non-luminous image display portion” refers to a portion other than a luminous image display portion that does not directly contribute to light emission in an image display portion. In the present invention, the non-luminous image display section includes elements such as an insulating layer that do not directly contribute to the luminescence phenomenon. Specifically, it refers to the entire portion indicated by 42 in FIG.

Therefore, strictly speaking, only the luminescent image display portion emits light when a voltage is applied, and only the luminescent image display portion functions as an organic EL element in a narrow sense. Therefore, in FIG. 2, the term “organic EL element” refers to each dot-shaped organic EL element 41 in a narrow sense, while in a broader sense, 10 including the entirety of the light emitting image display portion and the non-light emitting image display portion. Point.

(1.1) <<Structure of organic EL element>>
The organic EL device of the present invention has an image display portion sandwiched between an anode and a cathode facing each other on a substrate, and the image display portion includes a luminescent image display portion having a luminescent layer and a non-luminescent image display portion. Consists of The light-emitting image display section may have a charge injection layer and a charge transport layer in addition to the light-emitting layer. A small number of layers is preferable, and the charge injection layer and the charge transport layer may be omitted. A charge injection layer refers to a hole injection layer and an electron injection layer, and a charge transport layer refers to a hole transport layer and an electron transport layer. Further, considering the above, the organic EL element of the present invention refers to a broadly defined organic EL element including a non-luminous image display portion.

FIG. 1 is a conceptual diagram showing that narrowly-defined organic EL elements forming luminescent pixels are arranged in dots in a luminescent image display section according to the present invention. FIG. 2 is a schematic cross-sectional view showing an example of the organic EL device according to the invention.
When viewed in the direction perpendicular to the surface of the organic EL element 10 of the present invention from the substrate 1 side, blue (B) light emitting pixels 21, green (G) light emitting pixels 22, and red (R) light emitting pixels 23 are arranged. , are arranged in dots, and are preferably arranged so that a line made up of a plurality of dots or various figures can be drawn from the viewpoint of image display. Also, the dots are preferably formed and arranged as minute pixels that cannot be visually recognized as dots when the image on the image display device is observed by a normal visual observation method.

When the light-emitting layer according to the present invention is formed in dots, it is desirable that patterning is possible. A printing method using a mask having patterning openings may be used, but a non-contact method is preferable from the viewpoint of less damage to the non-light-emitting layer. Moreover, the dispenser method or the inkjet printing method is more preferable from the viewpoint of high resolution. The volume of the solution containing the luminescent dopant is 10 μL or less, preferably 100 pL or less.

The size of the dots is preferably in the range of 30 to 300 μm as a circle conversion particle size when measured based on an optical microscope photograph (plan view) taken from the main light emitting surface side of the light emitting layer.

In FIG. 1, portions other than dots are non-luminous image display portions. The non-light-emitting image display portion does not contribute to light emission unless it has a light-emitting layer, that is, it is non-light-emitting. They may be the same.

Originally, the non-light-emitting image display portion does not need to have elements that contribute to the expression of light-emitting properties, but by using the same layer as the light-emitting image display portion for the layers other than the light-emitting layer, the non-light-emitting image display portion can be formed by uniform coating or the like. , easy to manufacture. Also, by using an insulating layer instead of the light-emitting layer, it is possible to prevent electrons and holes, ie charge carriers, from entering.

The structure of the organic EL device of the present invention will be described with reference to FIG. FIG. 2 is a schematic cross-sectional view showing an example of the organic EL device according to the invention. The organic EL element 10 includes a substrate 11, an anode 12, a hole injection layer 13, a hole transport layer 14, a light emitting layer 15, an electron transport layer 16, an electron injection layer 17 and a cathode 18 in this order. Further, a hole blocking layer (hole blocking layer) and an electron blocking layer (electron blocking layer) may be provided. The layers from the hole injection layer to the electron injection layer are also referred to as "organic functional layers".

The element configuration of the organic EL element is not limited to the configuration example shown in FIG.

(1) Anode/light-emitting layer/cathode (2) Anode/hole-transporting layer/light-emitting layer/cathode (3) Anode/hole-transporting layer/light-emitting layer/electron-transporting layer/cathode (4) Anode/hole-transporting layer /Emissive layer/Electron transport layer/Electron injection layer/Cathode (5) Anode/Hole injection layer/Hole transport layer/Emissive layer/Electron transport layer/Cathode (6) Anode/Hole injection layer/Hole transport layer /Emitting layer/Electron transporting layer/Electron injection layer/Cathode (7) Anode/Hole injection layer/Emitting layer/Electron injection layer/Cathode (8) Anode/Emitting layer/Electron injection layer/Cathode (9) Anode/Positive Hole injection layer/light-emitting layer/cathode Among the above structures, (1), (2) and (9) are preferably used, but are not limited to these structures. may be omitted or added.

In the present invention, it is preferred that the light-emitting layer is directly adjacent to the charge injection layer or directly adjacent to the electrode from the viewpoint of controlling the mobility of charge carriers. The term "directly adjacent" means that there is no functional layer between the light-emitting layer and the charge injection layer or electrode, and the layers are in direct contact with each other.

Each of these layers can be formed by known materials and methods as long as they satisfy the provisions of the present invention. Each layer is described below.

(1.1.1) Constituent Elements of Luminescent Image Display [Luminous Layer]
The light-emitting layer is a layer that provides a field for recombination of electrons and holes injected from an electrode or an adjacent layer to emit light via excitons. The light-emitting layer is composed of a single layer or multiple layers.
That is, an organic electroluminescence element is an element using an organic light-emitting material that emits light when a voltage is applied. By applying a voltage, electrons and holes recombine in the light-emitting layer, and the excitons (excitons) generated at this time are deactivated, and light (electromagnetic waves) emitted when returning to the ground state is used. It is.

The light-emitting layer according to the present invention is adjacent to at least the electrode, the charge injection layer, or the charge transport layer, and contains a polymer having a conductivity of 1 S/m or less, a charge-transporting host compound (hereinafter also referred to as "host compound"), and a light-emitting layer. It is characterized by containing a sexual dopant. The light-emitting layer may be a single layer or multiple layers.

Further, in the light-emitting layer according to the present invention, the polymer ratio P represented by the following formula (i) satisfies the following condition (ii).
(i) _P =IP/( _{IP +} IH+ _IDp )
(ii) At least either Pa/Pb or Pc/Pb is 0.8 or more and less than 2.2.
[Wherein, I _P , I _H and I _Dp are a polymer, a charge-transporting host compound, and a luminous is the secondary ion intensity of the dopant.
Pa is the polymer ratio near the interface on the anode side (x = (D-[D/10])),
Pb is the polymer ratio in the central part (x=D/2),
Pc is the polymer ratio near the cathode-side interface (x=D/10).
However, x indicates the position in the thickness direction in the light-emitting layer. The anode-side interface is represented by x=D. ]

Generally, in the light-emitting layer, the host compound is responsible for the transport of electrons and holes, that is, charge carriers, and the path of charge carrier movement. It plays a role in preventing concentration quenching.

However, chemical species (ions, radicals, etc.) generated by driving the organic EL display device react with light-emitting materials such as light-emitting dopants and host compounds, resulting in deterioration. That is, when driving with a constant current, electrons and holes cannot recombine and remain as accumulated charges, and there is no opportunity for charged, unstable and activated chemical species (ions and radicals) to react with the light-emitting material. To increase. Therefore, from the viewpoint of life, it is preferable that the charge carrier balance is maintained.

Therefore, when a polymer with relatively low conductivity is contained in the light-emitting layer, the polymer exhibits blocking ability, and a host compound or a light-emitting dopant is added between the light-emitting layer and the adjacent layer or between the light-emitting layer and the electrode. The migration of chemical species such as charge carriers and active ions or radicals to is restricted. Therefore, the charge carrier balance is easily maintained, and the occurrence of factors contributing to quenching is easily suppressed. In addition, by localizing the polymer moderately at the electrode-side interface as compared with the central portion of the light-emitting layer, the blocking ability works more effectively, so that a remarkable effect can be obtained.

In addition, when the light-emitting layer is produced in the atmosphere, the host compound and the light-emitting dopant are highly reactive with oxygen and water, so they tend to react and lose their original functions. However, by dispersing the polymer in the light-emitting layer, the host compound and the light-emitting dopant are less likely to be exposed on the surface of the light-emitting layer when the film is dried in the atmosphere, so the reaction can be suppressed.

The thickness of the light emitting layer according to the present invention is not particularly limited, but from the viewpoint of the distance between the recombination region and the electron transport layer, it is preferably 50 nm or more, more preferably 70 nm or more. Moreover, from the viewpoint of driving voltage, it is preferably 150 nm or less.

A method for forming the light-emitting layer according to the present invention is not particularly limited, but a wet method or the like is preferable because the layer contains a polymer. In the case of forming by a wet method, it is preferable that the host compound and the light-emitting dopant are low-molecular-weight compounds from the viewpoint that they enter between polymer chains and are dispersed to increase the light-emitting efficiency.

Wet methods include, for example, spin coating, casting, inkjet printing, printing, die coating, blade coating, roll coating, dispenser, spray coating, curtain coating, LB (Langmuir-Blodgett Law) etc. can be used. Among them, a method applicable to a roll-to-roll system such as a die coating method, a roll coating method, a dispenser method, and an inkjet printing method is preferable because a homogeneous thin film can be easily obtained and high productivity can be achieved. The inkjet printing method will be described later.

The weight-average molecular weight of the polymer having a conductivity of 1 S/m or less according to the present invention is preferably a molecular weight of 1000 or more from the viewpoint of suppressing the effects of crystallization and diffusion of low-molecular-weight components, and a molecular weight of 3 million or less from the viewpoint of residual polymerization impurities. things are preferred. The weight average molecular weight can be measured using gel permeation chromatography (GPC) described later.

The molecular weights of the host compound and the luminescent dopant according to the present invention are not limited, and may be high or low molecular weight. In the wet method, it is necessary to dissolve these light-emitting layer materials in a solvent, so compounds having a molecular weight of 3,000 or less are preferable. It is more preferable to have

Examples of the liquid medium for dissolving or dispersing the light-emitting layer material include alcohols such as isopropanol and tetrafluoropropanol, ketones such as methyl ethyl ketone and cyclohexanone, fatty acid esters such as ethyl acetate, and halogenated carbons such as chloroform and dichlorobenzene. Hydrogens, aromatic hydrocarbons such as toluene, xylene, mesitylene and cyclohexylbenzene, aliphatic hydrocarbons such as cyclohexane, decalin and dodecane, and organic solvents such as dimethylformamide (DMF) and dimethylsulfoxide (DMSO). can be done. A solvent obtained by mixing two or more of these can also be applied.

In addition, when dispersing the light-emitting layer material in a liquid medium, for example, ultrasonic dispersion, high shear force dispersion using a screw, microchannel, nozzle pressure, etc., media dispersion using a stirrer or bead mill, etc. It can be dispersed by a dispersion method.

The light-emitting layer can be formed under the atmosphere or under an inert gas. Also in the formation of , it is preferable to be in the atmosphere. This is because, according to the means of the present invention, not only is the deterioration of performance suppressed even in atmospheric production, but also the cost of equipment can be reduced. Furthermore, in the atmosphere, the adsorption of the adsorbed active gas on the surface of the light-emitting layer is saturated, and the degree of atmospheric deterioration is evened out, so there is an advantage that variations in chromaticity and uneven light emission can be suppressed.

Further, the molecular structures of the host compound and the luminescent dopant are not particularly limited, but they have a dibenzofuran ring, a dibenzothiophene ring or a carbazole ring and an alkyl group, an alkenyl group, an alkynyl group or an arylalkyl group. From the viewpoint of improving the probability of recombination, it is preferable to contain a compound that does not

<polymer>
The polymer according to the present invention is characterized by having a conductivity of 1 S/m or less.
In addition, "conductivity (also referred to as "electrical conductivity" or "electrical conductivity")" refers to a value that is an index representing how easily electricity can pass, and the reciprocal of electrical resistivity is the SI unit is expressed as S/m (Siemens per meter).

As the electric resistivity, a value obtained under conditions conforming to JIS-K-6911 by a constant voltage application/leakage current measurement method using a double ring electrode is used.

A conductivity of 1 S/m or less facilitates controlling the movement of injected electrons and holes, ie charge carriers. More preferably, the conductivity is 1E-8 S/m or less.
On the other hand, when the electrical conductivity exceeds 1 S/m, the rate of charge transfer through the polymer becomes more rate-determining than the charge transfer to the host compound or dopant, and the recombination probability decreases.

The polymer is not limited as long as it has an electrical conductivity of 1 S/m or less. Examples include polyalkylenes such as polyethylene, polypropylene, polyvinylidene fluoride, and polyacrylonitrile, polycarbonate, polyethylene terephthalate, polyethylene naphthalate, polyphenyl ether, and polyethylene. Benzene ring-containing polymers such as ether ketone, polyphenylene sulfide, polyphenylene sulfone, polysulfone, polyether sulfone, polyarylate, polystyrene, and polyvinyl phenol, cured resins such as phenol resins and epoxy resins, derivatives of these resins, and the like can be used. can.

(Aromatic ring-containing polymer)
Polymers used in the present invention are preferably aromatic ring-containing polymers having structures represented by the following general formulas (I) and (II). In particular, polymers containing benzene rings are preferred. Moreover, it is preferable that the polymer containing the benzene ring has an electrical conductivity of 1 S/m or less. Further, the polymer is preferably a polymer containing benzene rings as side chains, such as polystyrene or polystyrene derivatives.
The aromatic ring-containing polymers having structures represented by the following general formulas (I) and (II) will be described in detail below.

[In the general formulas (I) and (II) above, A represents an aromatic ring, and the aromatic ring includes an aromatic hydrocarbon ring and an aromatic heterocyclic ring. x and y represent integers of 0 or more, and when one of them is 0, the other is 1 or more. n represents an integer of 1 or more. n represents the degree of polymerization and ranges from 10 to 100,000. ]

In general formulas (I) and (II) above, the aromatic hydrocarbon ring and aromatic heterocyclic ring represented by A may each be a monocyclic ring or a condensed ring. It is preferably an aromatic hydrocarbon ring from the viewpoint that the electrical conductivity is 1 S/m or less. From the viewpoint of solubility, the number of atoms constituting the aromatic ring excluding substituents is preferably 20 or less, more preferably 12 or less, and even more preferably 6 or less.

Examples of aromatic hydrocarbon rings include benzene ring, naphthalene ring, fluorene ring, anthracene ring, phenthrene ring, tetracene ring, pentacene ring, chrysene ring, pyrene ring, perylene ring, coronene ring, fluoranthene ring, dibenzoanthracene ring, Examples include acene structures such as benzopyrene ring, preferably benzene ring and naphthalene ring.
Examples of aromatic heterocyclic rings include pyridine ring, pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring, acridine ring, thiophene ring, furan ring, pyrrole ring, benzofuran ring, benzothiophene ring, indole ring, imidazole ring and pyrazole ring. , oxazole ring, isoxazole ring, thiazole ring, isothiazole ring, triazole ring, oxadiazole ring, thiadiazole ring, dioxazole ring, dithiazole ring, tetrazole ring, pentazole ring and the like.
The aromatic ring represented by A is preferably a benzene ring, and may further have a substituent, from the viewpoint of compatibility with the light-emitting layer material through interaction. Specific examples thereof include rings having a structure containing a benzene ring represented by the following general formula (III).

[R ₁ to R ₅ represent hydrogen or a substituent, each independently hydrogen atom, deuterium atom, halogen atom, hydroxy group, carboxyl group, sulfo group, alkoxycarbonyl group, haloformyl group, formyl group, acyl group; , alkoxy group, mercapto group, cyano group, alkyl group, alkenyl group, alkynyl group, alkoxy group, amino group, carbamoyl group, silyl group, phosphine oxide group, imide group, aromatic imide ring group, aromatic hydrocarbon ring group , an aromatic heterocyclic group, a non-aromatic hydrocarbon ring group, or a non-aromatic heterocyclic group, which may further have a substituent.
X and Y represent hydrogen or a bond with repeating unit L or A in general formulas (I) and (II). ]

In the general formulas (I) and (II), L each represents a divalent linking group, an alkylene group, an alkenylene group, a carbonyl group, an ether group, an imino group, an imide group, an amide group, and an o-phenylene group. , m-phenylene group, p-phenylene group, sulfonyl group, sulfide group, thioester group, silyl group, phosphine oxide group, or divalent aromatic heterocyclic group, which may further have a substituent.

Examples of the alkylene group represented by L in the general formulas (I) and (II) include methylene group, ethylene group, trimethylene group, propylene group, butylene group, butane-1,2-diyl group and hexylene group. etc.
Examples of alkenylene groups represented by L include vinylene group, propenylene group, butenylene group, pentenylene group, 1-methylvinylene group, 1-methylpropenylene group, 2-methylpropenylene group, 1-methylpen Thenylene group, 3-methylpentenylene group, 1-ethylvinylene group, 1-ethylpropenylene group, 1-ethylbutenylene group, 3-ethylbutenylene group and the like.

Amido groups represented by L include, for example, a methylcarbonylamino group, an ethylcarbonylamino group, a dimethylcarbonylamino group, a propylcarbonylamino group, a pentylcarbonylamino group, a cyclohexylcarbonylamino group and a 2-ethylhexylcarbonylamino group. , an octylcarbonylamino group, a dodecylcarbonylamino group, a phenylcarbonylamino group, a naphthylcarbonylamino group, and the like.
Further, the divalent aromatic heterocyclic group represented by L includes, for example, a divalent heterocyclic group derived from the aromatic heterocyclic groups represented by R ₁ to R ₅ in the above general formula. groups.

In the above general formulas (I) to (III), examples of alkyl groups represented by R ₁ to R ₅ include methyl group, ethyl group, propyl group, isopropyl group, (t) butyl group, pentyl group, hexyl group, octyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, benzyl group and the like.

Alkenyl groups represented by R ₁ to R ₅ include, for example, those having one or more double bonds in the above alkyl group, more specifically vinyl group, allyl group, 1- propenyl group, isopropenyl group, 2-butenyl group, 1,3-butadienyl group, 2-pentenyl group, 2-hexenyl group and the like.

Examples of alkynyl groups represented by R ₁ to R ₅ include ethynyl group, acetylenyl group, 1-propynyl group, 2-propynyl group (propargyl group), 1-butynyl group, 2-butynyl group, 3- butynyl group, 1-pentynyl group, 2-pentynyl group, 3-pentynyl group, 1-hexynyl group, 2-hexynyl group, 3-hexynyl group, 1-heptynyl group, 2-heptynyl group, 5-heptynyl group, 1- octynyl group, 3-octynyl group, 5-octynyl group and the like.

Examples of aromatic hydrocarbon ring groups (also referred to as aryl groups) represented by R ₁ to R ₅ include phenyl group, p-chlorophenyl group, mesityl group, tolyl group, xylyl group, naphthyl group and anthryl group. group, azulenyl group, acenaphthenyl group, fluorenyl group, phenanthryl group, indenyl group, pyrenyl group, biphenylyl group and the like.

Examples of aromatic heterocyclic groups represented by R ₁ to R ₄ include pyridyl group, pyrimidinyl group, furyl group, pyrrolyl group, imidazolyl group, benzimidazolyl group, pyrazolyl group, pyrazinyl group and triazolyl group (e.g., 1,2,4-triazol-1-yl group, 1,2,3-triazol-1-yl group, etc.), oxazolyl group, benzoxazolyl group, thiazolyl group, isoxazolyl group, isothiazolyl group, furazanyl group, thienyl group, quinolyl group, benzofuryl group, dibenzofuryl group, benzothienyl group, dibenzothienyl group, indolyl group, carbazolyl group, carbolinyl group, diazacarbazolyl group (one of the carbon atoms constituting the carboline ring of the carbolinyl group is ), a quinoxalinyl group, a pyridazinyl group, a triazinyl group, a quinazolinyl group, a phthalazinyl group, and the like.

Examples of non-aromatic hydrocarbon ring groups represented by R ₁ to R ₅ include cycloalkyl groups (e.g., cyclopentyl group, cyclohexyl group, etc.), cycloalkoxy groups (e.g., cyclopentyloxy group, cyclohexyloxy group). etc.), cycloalkylthio groups (eg, cyclopentylthio group, cyclohexylthio group, etc.), tetrahydronaphthalene rings, 9,10-dihydroanthracene rings, biphenylene rings, and the like.

Examples of non-aromatic hydrocarbon ring groups represented by R ₁ to R ₅ include epoxy ring, aziridine ring, thiirane ring, oxetane ring, azetidine ring, thietane ring, tetrahydrofuran ring, dioxolane ring, pyrrolidine ring, pyrazolidine ring, imidazolidine ring, oxazolidine ring, tetrahydrothiophene ring, sulfolane ring, thiazolidine ring, ε-caprolactone ring, ε-caprolactam ring, piperidine ring, hexahydropyridazine ring, hexahydropyrimidine ring, piperazine ring, morpholine ring, tetrahydro pyran ring, 1,3-dioxane ring, 1,4-dioxane ring, trioxane ring, tetrahydrothiopyran ring, thiomorpholine ring, thiomorpholine-1,1-dioxide ring, pyranose ring, diazabicyclo[2,2,2] - monovalent groups derived from octane ring, phenoxazine ring, phenothiazine ring, oxantrene ring, thioxanthene ring, phenoxathiin ring and the like.
Examples of alkoxy groups represented by R ₁ to R ₅ in the general formula above include methoxy, ethoxy, propoxy, isopropoxy, butoxy, pentyloxy, hexyloxy, and 2-ethylhexyloxy groups. , octyloxy group, nonyloxy group, decyloxy group, undecyloxy group, dodecyloxy group, tridecyloxy group, tetradecyloxy group, pentadecyloxy group, hexadecyloxy group, heptadecyloxy group, octadecyloxy group, etc. mentioned.

Examples of acyl groups represented by R ₁ to R ₅ include acetyl group, ethylcarbonyl group, propylcarbonyl group, pentylcarbonyl group, cyclohexylcarbonyl group, octylcarbonyl group, 2-ethylhexylcarbonyl group and dodecylcarbonyl group. , phenylcarbonyl group, naphthylcarbonyl group, pyridylcarbonyl group and the like.
Examples of amino groups represented by R ₁ to R ₅ include amino group, ethylamino group, dimethylamino group, butylamino group, cyclopentylamino group, 2-ethylhexylamino group, dodecylamino group, anilino group, A naphthylamino group, a 2-pyridylamino group and the like can be mentioned.

Examples of the silyl group represented by R ₁ to R ₅ include trimethylsilyl group, triisopropylsilyl group, triphenylsilyl group and phenyldiethylsilyl group.

Phosphine oxide groups represented by R ₁ to R ₅ include, for example, diphenylphosphine oxide group, ditolylphosphine oxide group, dimethylphosphine oxide group, dinaphthylphosphine oxide group, 9,10-dihydro-9-oxa -10-phosphaphenanthrene-10-oxide group and the like.

Substituents that the groups represented by R ₁ to R ₅ may further have include, for example, each independently alkyl group (eg, methyl group, ethyl group, propyl group, isopropyl group, (t) butyl group, pentyl group, hexyl group, octyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, benzyl group, etc.), cycloalkyl group (e.g., cyclopentyl group, cyclohexyl group, etc.), alkenyl group (e.g., vinyl group, allyl group, etc.), alkynyl group (e.g., propargyl group, etc.), aromatic hydrocarbon group (also called aryl group, e.g., phenyl group, p-chlorophenyl group, mesityl group, tolyl group, xylyl group, naphthyl group, anthryl group) , azulenyl group, acenaphthenyl group, fluorenyl group, phenanthryl group, indenyl group, pyrenyl group, biphenylyl group, etc.), heterocyclic group (e.g., epoxy ring, aziridine ring, thiirane ring, oxetane ring, azetidine ring, thietane ring, tetrahydrofuran ring , dioxolane ring, pyrrolidine ring, pyrazolidine ring, imidazolidine ring, oxazolidine ring, tetrahydrothiophene ring, sulfolane ring, thiazolidine ring, ε-caprolactone ring, ε-caprolactam ring, piperidine ring, hexahydropyridazine ring, hexahydropyrimidine ring, piperazine ring, morpholine ring, tetrahydropyran ring, 1,3-dioxane ring, 1,4-dioxane ring, trioxane ring, tetrahydrothiopyran ring, thiomorpholine ring, thiomorpholine 1,1-dioxide ring, pyranose ring, diazabicyclo [ 2,2,2]-octane ring, etc.), aromatic heterocyclic groups (pyridyl group, pyrimidinyl group, furyl group, pyrrolyl group, imidazolyl group, benzimidazolyl group, pyrazolyl group, pyrazinyl group, triazolyl group (e.g., 1,2 ,4-triazol-1-yl group, 1,2,3-triazol-1-yl group, etc.), oxazolyl group, benzoxazolyl group, thiazolyl group, isoxazolyl group, isothiazolyl group, furazanyl group, thienyl group, quinolyl group, benzofuryl group, dibenzofuryl group, benzothienyl group, dibenzothienyl group, indolyl group, carbazolyl group, carbolinyl group, diazacarbazolyl group (one of the carbon atoms constituting the carboline ring of the carbolinyl group is a nitrogen atom; ), quinoxalinyl group, pyridazinyl group, triazinyl group, quinazolinyl group, phthalazinyl group, etc.), halogen atom (e.g., chlorine atom, bromine atom, iodine atom, fluorine atom, etc.), alkoxy groups (e.g., methoxy group, ethoxy group, propyloxy group, pentyloxy group, hexyloxy group, octyloxy group, dodecyloxy group, etc.), Cycloalkoxy group (e.g., cyclopentyloxy group, cyclohexyloxy group, etc.), aryloxy group (e.g., phenoxy group, naphthyloxy group, etc.), alkylthio group (e.g., methylthio group, ethylthio group, propylthio group, pentylthio group, hexylthio group) , octylthio group, dodecylthio group, etc.), cycloalkylthio group (e.g., cyclopentylthio group, cyclohexylthio group, etc.), arylthio group (e.g., phenylthio group, naphthylthio group, etc.), alkoxycarbonyl group (e.g., methyloxycarbonyl group, ethyl oxycarbonyl group, butyloxycarbonyl group, octyloxycarbonyl group, dodecyloxycarbonyl group, etc.), aryloxycarbonyl group (e.g., phenyloxycarbonyl group, naphthyloxycarbonyl group, etc.), sulfamoyl group (e.g., aminosulfonyl group, methyl aminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, octylaminosulfonyl group, dodecylaminosulfonyl group, phenylaminosulfonyl group, naphthylaminosulfonyl group, 2-pyridylaminosulfonyl group, etc. ), ureido group (e.g., methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, octylureido group, dodecylureido group, phenylureido group, naphthylureido group, 2-pyridylaminoureido group, etc.), acyl group ( For example, acetyl group, ethylcarbonyl group, propylcarbonyl group, pentylcarbonyl group, cyclohexylcarbonyl group, octylcarbonyl group, 2-ethylhexylcarbonyl group, dodecylcarbonyl group, phenylcarbonyl group, naphthylcarbonyl group, pyridylcarbonyl group, etc.), acyloxy groups (e.g., acetyloxy group, ethylcarbonyloxy group, butylcarbonyloxy group, octylcarbonyloxy group, dodecylcarbonyloxy group, phenylcarbonyloxy group, etc.), amide groups (e.g., methylcarbonylamino group, ethylcarbonylamino group, dimethylcarbonylamino group, propylcarbonylamino group amino group, pentylcarbonylamino group, cyclohexylcarbonylamino group, 2-ethylhexylcarbonylamino group, octylcarbonylamino group, dodecylcarbonylamino group, phenylcarbonylamino group, naphthylcarbonylamino group, etc.), carbamoyl group (e.g., aminocarbonyl group , methylaminocarbonyl group, dimethylaminocarbonyl group, propylaminocarbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group, octylaminocarbonyl group, 2-ethylhexylaminocarbonyl group, dodecylaminocarbonyl group, phenylaminocarbonyl group, naphthylamino carbonyl group, 2-pyridylaminocarbonyl group, etc.), sulfinyl group (e.g., methylsulfinyl group, ethylsulfinyl group, butylsulfinyl group, cyclohexylsulfinyl group, 2-ethylhexylsulfinyl group, dodecylsulfinyl group, phenylsulfinyl group, naphthylsulfinyl group, 2-pyridylsulfinyl group, etc.), alkylsulfonyl group or arylsulfonyl group (e.g., methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, 2-ethylhexylsulfonyl group, dodecylsulfonyl group, phenylsulfonyl group, naphthylsulfonyl group group, 2-pyridylsulfonyl group, etc.), amino group (e.g., amino group, ethylamino group, dimethylamino group, butylamino group, cyclopentylamino group, 2-ethylhexylamino group, dodecylamino group, anilino group, diarylamino group (e.g., diphenylamino group, dinaphthylamino group, phenylnaphthylamino group, etc.), naphthylamino group, 2-pyridylamino group, etc.), nitro group, cyano group, hydroxy group, mercapto group, alkylsilyl group or arylsilyl group ( For example, trimethylsilyl group, triethylsilyl group, (t) butyldimethylsilyl group, triisopropylsilyl group, (t) butyldiphenylsilyl group, triphenylsilyl group, trinaphthylsilyl group, 2-pyridylsilyl group, etc.), alkylphos phino group or arylphosphino group (dimethylphosphino group, diethylphosphino group, dicyclohexylphosphino group, methylphenylphosphino group, diphenylphosphino group, dinaphthylphosphino group, di(2-pyridyl)phosphino group), Alkylphosphoryl group or arylphosphoryl group (dime chylphosphoryl group, diethylphosphoryl group, dicyclohexylphosphoryl group, methylphenylphosphoryl group, diphenylphosphoryl group, dinaphthylphosphoryl group, di(2-pyridyl)phosphoryl group), alkylthiophosphoryl group or arylthiophosphoryl group (dimethylthiophosphoryl group, diethylthiophosphoryl group, dicyclohexylthiophosphoryl group, methylphenylthiophosphoryl group, diphenylthiophosphoryl group, dinaphthylthiophosphoryl group, di(2-pyridyl)thiophosphoryl group). These substituents may be further substituted with the above substituents, or they may be condensed with each other to form a ring.

In general formulas (I) and (II), the degree of polymerization n is preferably within the range of 10 to 100000, and the copolymerization ratio x:y is within the range of 1:99 to 99:1. is preferred. These repeating structures, for example, may be sequentially polymerized like the repetition of AL, ALLA, ALLA , may be block-polymerized. When both or either one of x and y is 2 or more, 2 or more of A, L and R ₁ to R ₅ may be the same or different.

Specific examples of the polymer according to the present invention are shown below, but the present invention is not limited thereto. n, x and y represent integers as defined above.

In the following examples, devices using polymers represented by the following structural formulas (1) to (3) are described as comparative examples, but the polymer ratio does not satisfy the numerical specification in the present invention. It can be used in the present invention if it satisfies the numerical specification.

In the structural formula of the polymer, the degree of polymerization n is preferably within the range of 10 to 100,000. In the structural formulas (15) and (25) above, the copolymerization ratio is preferably within the range of x:y=1:99 to 99:1.
The weight-average molecular weight is preferably 1,000 or more from the viewpoint of suppressing the influence of crystallization and diffusion of low-molecular-weight components, and preferably has a molecular weight of 3,000,000 or less from the viewpoint of residual polymerization impurities. More preferably, it is 50,000 or more and 1,000,000 or less.

The weight average molecular weight as used herein means the weight average molecular weight measured by gel permeation chromatography (GPC) using dimethylformamide as a solvent and converted to polystyrene. If it cannot be measured with dimethylformamide, use tetrahydrofuran. If it cannot be measured, use hexafluoroisopropanol. If it cannot be measured with hexafluoroisopropanol, use 2-chloronaphthalene.

From the viewpoint of compatibility with the light-emitting layer material through interaction, the polymer is preferably a polymer containing a benzene ring. (25) and (27)-(29).

Further, from the viewpoint of ease of electronic interaction with the electrode and adjacent layers, it is more preferable to use a polymer containing a benzene ring in a side chain. 16), (24), (25), (28) and (29).

Furthermore, from the viewpoint of increasing the density of the light-emitting layer, polymers composed of polystyrene and polystyrene derivatives are particularly preferable.

The light-emitting layer according to the present invention contains a polymer, a host compound, and a light-emitting dopant, each of which is dispersed in the light-emitting layer, thereby having functionality, but containing a relatively high molecular weight polymer. Therefore, it is necessary for the relatively low-molecular-weight host compound and the luminescent dopant to enter the interstices between the polymers. However, many host compounds and luminescent dopants have structures with benzene rings, and by including benzene rings in the polymer, the benzene rings interact with each other, and the host compound and emissive dopants can enter.

In addition, since the benzene ring is included in the side chain of the polymer, it is possible to maintain the elasticity of the main chain while maintaining the dispersibility of the host compound and the luminescent dopant as described above. become more likely to electronically interact with

Furthermore, since the polymer is a polymer composed of polystyrene and polystyrene derivatives, it is possible to utilize the effects of interactions of both Π-conjugated planes and hydrogen bonds. It becomes easy to discharge the solvent molecules that are the cause of the film formation and drying.

Preferably, the polymer is a mixture of components with different stereoregularities. By being a mixture of components with different stereoregularity, gaps between the polymers are entangled with each other, so that the host compound and the luminescent dopant can enter more easily. The mixing ratio is preferably 0.1% or more and 50% or less, more preferably 1% or more and 25% or less, from the viewpoint of easily obtaining the above gap.

The polymer ratio P according to the present invention is represented by the following formula (i).
(i) _P =IP/( _{IP +} IH+ _IDp )
In the formula, I _P , I _H and I _Dp are a polymer, a charge-transporting host compound and a light-emitting dopant with a conductivity of 1 S/m or less as measured by time-of-flight secondary ion mass spectrometry (TOF-SIMS). is the secondary ion intensity of Measurement conditions are shown below.

Primary ion: Double charged ion of bismuth cluster (Bi ³⁺⁺ )
Primary ion acceleration voltage: 30 kV
Mass range (m/z): 0-1500
Measurement range: 100 μm×100 μm
Number of scans: 16 scans/cycle
Number of pixels (one side): 256 pixels
Etching ion: Ar gas cluster ion beam (Ar-GCIB)
Etching ion acceleration voltage: 5.0 kV

In the present invention, the polymer ratio P in the central portion of the light-emitting layer and in the vicinity of the interface on the electrode side is expressed as follows.
Pa: near the interface on the anode side (x = (D-[D/10]))
Pb: central part (x=D/2)
Pc: near the interface on the cathode side (x=D/10)
However, x indicates the position in the thickness direction in the light-emitting layer. The anode-side interface is represented by x=D.

The polymer ratio P according to the present invention is characterized in that at least either one of the polymer ratio Pa/Pb or Pc/Pb is 0.8 or more and less than 2.2.

The distribution of the polymer in the light-emitting layer can be roughly determined from the numerical values (Pa/Pb and Pc/Pb) obtained by dividing the polymer ratio (Pa and Pc) in the vicinity of the interface on the electrode side by the polymer ratio Pb in the central portion. . That is, the Pa/Pb value roughly indicates the distribution state from the central portion to the anode-side interface in the light-emitting layer, and the Pc/Pb value roughly indicates the distribution state from the central portion to the cathode-side interface.

For example, when it is less than 1, the polymer is relatively centrally concentrated, and when it is greater than 1, the polymer is relatively localized on the electrode side interface. Moreover, when it is close to 1, it is considered that the polymer is contained approximately uniformly.

By properly dispersing the polymer in the light-emitting layer, the host compound and the light-emitting dopant can also be dispersed in the light-emitting layer. Therefore, the host compound can appropriately exhibit charge carrier transportability. Also, for a luminescent dopant, quenching caused by aggregation can be prevented.

The polymer ratio P represented by formula (i) can be controlled by the structure of the polymer used.
By including an aromatic ring such as benzene in the polymer molecule, it becomes easier for the polymer to interact with the crystal lattice of the electrode at the interface on the substrate side when the light-emitting layer is applied or the aromatic ring of the adjacent layer material, and the polymer is relatively close to the electrode side. It is easy to create a structure localized at the interface.
Further, when a polar group is contained in the polymer molecule, the polymer molecule tends to aggregate on the outermost surface so as to increase the tension of the film surface and form a stable film structure, thereby easily creating a localized state of Pa<Pc.

The polymer ratio P can also be controlled by using a plurality of polymers and adjusting the content ratio, as shown in the examples below.

Regarding the polymer ratio in the vicinity of the interface on the electrode side, Pa≦Pc is preferable, and Pa<Pc is more preferable, from the viewpoint of maintaining the charge carrier balance.

When the total weight of the polymer, host compound and luminescent dopant is 100, the weight ratio of the polymer is preferably 5 to 80% by weight. Within the above range, the polymer is sufficiently present at the interface on the electrode side, so that movement of chemical species such as charge carriers and compounds can be restricted between the light-emitting layer and the adjacent layer or between the light-emitting layer and the electrode. Thus, the charge carrier balance can be maintained, and the occurrence of factors that cause deterioration and quenching of the organic EL element can be suppressed. The mass ratio of the polymer is more preferably 10-75% by mass, still more preferably 25-60% by mass.

<Charge-transporting host compound>
The charge-transporting host compound is a compound mainly responsible for charge injection and transport in the light-emitting layer, and is preferably a compound whose light emission itself is substantially not observed in the organic EL device.

As the host compound used in the light-emitting layer, compounds conventionally used in organic EL devices can be used. For example, it may be a low-molecular-weight compound, a polymer compound having repeating units, or a compound having a reactive group such as a vinyl group or an epoxy group.

As a known host compound, from the viewpoint of stability against heat generation during high-temperature driving of an organic EL device or during driving of the device, It preferably has a high glass transition temperature (Tg). The host compound preferably has a Tg of 80° C. or higher, more preferably 100° C. or higher.

Here, the glass transition point (Tg) is a value determined by a method based on JIS-K-7121 using DSC (Differential Scanning Colorimetry).

From the viewpoint of drive stability, the host compound must be able to exist stably in all active species states of cation radical state, anion radical state, and excited state, and not undergo chemical changes such as decomposition and addition reactions. It is preferable that the host molecules do not migrate at the angstrom level in the layer during the passage of current.

The host compound that can be used in the present invention is not particularly limited, and compounds that are conventionally used in organic EL devices can be used. Representative examples are those having a basic skeleton such as carbazole derivatives, triarylamine derivatives, aromatic derivatives, nitrogen-containing heterocyclic compounds, thiophene derivatives, furan derivatives, oligoarylene compounds, etc., or carboline derivatives and diazacarbazole derivatives (here and the diazacarbazole derivative means that at least one carbon atom of the hydrocarbon ring constituting the carboline ring of the carboline derivative is substituted with a nitrogen atom.) and the like.

A known host compound that can be used in the present invention is preferably a compound that has a hole-transporting ability and an electron-transporting ability, prevents emission from becoming longer in wavelength, and has a high Tg as described above.

Moreover, in the present invention, a conventionally known host compound may be used alone, or a plurality of types may be used in combination. By using a plurality of types of host compounds, it is possible to adjust the movement of electric charges, and to improve the efficiency of the organic EL device. In addition, by using a plurality of conventionally known compounds, it is possible to mix different luminescence, thereby obtaining an arbitrary luminescence color.

The host compound used in the present invention may be a low-molecular-weight compound, a high-molecular-weight compound having a repeating unit, or a low-molecular-weight compound (polymerizable host compound) having a polymerizable group such as a vinyl group or an epoxy group. Well, one or more of such compounds may be used.

When a known host compound is used in the organic EL device of the present invention, specific examples thereof include compounds described in the following documents, but the present invention is not limited thereto.

JP 2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357977, 2002-334786, 2002-8860, 2002-334787, 2002-15871, 2002-334788, 2002-43056, 2002-334789, 2002-75645, 2002-338579, 2002-105445, 2002-343568, 2002-141173, 2002-352957, 2002-203683, 2002-363227, 2002-231453, 2003 -3165, 2002-234888, 2003-27048, 2002-255934, 2002-260861, 2002-280183, 2002-299060, 2002- 302516, 2002-305083, 2002-305084, 2002-308837, 2016-178274, US Patent Application Publication No. 2003/0175553, US Patent Application Publication No. 2006 US2005/0112407, US2009/0017330, US2009/0030202, US2005/0238919 No., WO 2001/039234, WO 2009/021126, WO 2008/056746, WO 2004/093207, WO 2005/089025, WO 2007/063796 WO 2007/063754, WO 2004/107822, WO 2005/030900, WO 2006/114966, WO 2009/086028, WO 2009/003898, WO 2012/023947, JP 2008-074939, JP 2007-254297, EP 2034538, WO 2011/055933, WO 2012/035853, JP 2015-38941 and US Patent Application Publication No. 2017/056814.

Among them, the host compound of the present invention is preferably a host compound that dissolves in a non-halogen solvent, and more preferably a host compound that dissolves in an ester solvent. This is because a halogen solvent has the problem of dissolving the lower layer if there is an adjacent layer. There is no particular limitation when the adjacent layer is an electrode. Moreover, it is preferable that the molecular weight of the host compound is 1000 or less because it is easily dissolved.

When the total mass of the polymer, host compound, and luminescent dopant is 100, the mass ratio of the host compound is preferably 10% or more from the viewpoint of charge transport, and 75% from the viewpoint of being susceptible to the dispersion effect of the polymer. % or less. More preferably, it is in the range of 30-60%.

The host compound used in the present invention is preferably a compound having a structure represented by the following general formula.

[Compound Having Structure Represented by General Formula (1)]
The light-emitting layer is preferably formed using a coating liquid containing a compound having a structure represented by the following general formula (1).

[In general formula (1), _X represents O, S, or NR9. R ₉ is a hydrogen atom, deuterium atom, alkyl group, alkenyl group, alkynyl group, arylalkyl group, aromatic hydrocarbon ring group, aromatic heterocyclic group, non-aromatic hydrocarbon ring group, non-aromatic heterocyclic ring group or a substituent represented by the following general formula (2). R ₁ to R ₈ each represent a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an acyl group, an amino group, a silyl group, a phosphine oxide group, and an aromatic hydrocarbon group. It represents a hydrogen ring group, an aromatic heterocyclic group, a non-aromatic hydrocarbon ring group, a non-aromatic heterocyclic group, or a substituent represented by the following general formula (2). At least one of R ₁ to R ₉ represents a substituent represented by general formula (2) below. R ₁ to R ₉ may be the same or different, and may have a substituent. ]

[In the general formula (2), each L represents an alkylene group, an alkenylene group, an o-phenylene group, an m-phenylene group, a p-phenylene group, an amide group or a divalent aromatic heterocyclic group, and further substituted You may have a group. n represents an integer of 1-8. When n represents an integer of 2 or more, 2 or more L's may be the same or different. R is an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a fluorinated alkyl group having 1 to 20 carbon atoms, an aromatic hydrocarbon ring group, an aromatic heterocyclic group or a non-aromatic represents a group hydrocarbon ring group, which may further have a substituent. m represents an integer of 1 to 3; At least one of L and R represents an alkylene group or an alkyl group. When there are a plurality of substituents represented by general formula (2), L and R may be the same or different, but are not linked to form a ring. ]

The substituents represented by R ₁ to R ₉ in general formula (1) have the same meanings as R ₁ to R ₆ in general formulas (I) to (III). Further, the linking group represented by L in the general formula (2) has the same definition as L in the general formulas (I) and (II).

Examples of the alkyl group having 1 to 20 carbon atoms represented by R in the above general formula (2) include those listed as the alkyl groups represented by R ₁ to R ₉ in the above general formula (1). Among them, groups having 1 to 20 carbon atoms are exemplified.

Examples of the fluorinated alkyl group having 1 to 20 carbon atoms represented by R include groups in which hydrogen atoms of the above alkyl groups having 1 to 20 carbon atoms are substituted with fluorine atoms.

The alkoxy group having 1 to 20 carbon atoms represented by R includes, for example, those exemplified as the alkoxy groups represented by R ₁ to R ₈ in the general formula (1) having 1 to 20 carbon atoms. Twenty groups are mentioned.

Examples of the aromatic hydrocarbon ring group, aromatic heterocyclic group or non-aromatic hydrocarbon ring group represented by R include aromatic hydrocarbons represented by R ₁ to R ₉ in the above general formula (1) The same as the cyclic group, aromatic heterocyclic group or non-aromatic hydrocarbon cyclic group can be mentioned.

In general formula (2), the substituents that L and R may further have include, for example, the same substituents that R ₁ to R ₉ may have in general formula (1). things are mentioned.

As the compound having the structure represented by the general formula (1), among the substituents represented by the general formula (2), at least one L is preferably an alkylene group having 1 to 6 carbon atoms. Also, among the substituents represented by formula (2), at least one R is preferably an alkyl group having 1 to 6 carbon atoms.

Specific examples of the compound having the structure represented by formula (1) according to the present invention are shown below, but the present invention is not limited thereto.

<Luminescent dopant>
A "luminescent dopant" according to the present invention refers to an organic luminescent compound that emits light by the following mechanism when a voltage is applied. By sandwiching the light-emitting layer between a cathode and an anode and applying a voltage, injected electrons and holes recombine on molecules of the light-emitting dopant in the light-emitting layer. The luminescent dopant is excited by the energy generated at this time. Then, light is generated when returning from the excited state to the ground state. Fluorescence is emitted when the excited state (singlet) returns to the ground state, and phosphorescence is emitted when the singlet state returns to the ground state via a triplet state with a slightly lower energy level.

Excitons generated by recombination of electrons and holes include singlet excitons and triplet excitons. 75%. Normally, at room temperature, light emission from an organic compound is only from light emission (fluorescence) from the singlet excited state, and the remaining 75% triplet excited state is thermally deactivated without emitting light. That is, only 25% of the excitons obtained by recombination contribute to light emission, and it is considered that the light emission efficiency can be significantly improved by utilizing the remaining 75% of excitons for light emission.

In recent years, by reducing the energy gap between the singlet excited state and the triplet excited state, Adachi et al. Reverse intersystem crossing occurs from the state to the singlet excited state, resulting in a phenomenon that enables nearly 100% fluorescence emission (also referred to as thermally activated delayed fluorescence or thermally excited delayed fluorescence: “TADF”: thermally activated delayed fluorescence) and fluorescent compounds that enable it have been found (for example, non-patent literature H. Uoyama, et al., Nature, 2012, 492, 234-238, H. Nakanotani, et al., Nature Communication, 2014, 5, 4016-4022, etc.).

As the luminescent dopant used for the above-mentioned "fluorescence emission" and "phosphorescence emission", a fluorescent dopant (also referred to as a fluorescent dopant or a fluorescent compound) or a phosphorescent dopant (phosphorescent dopant, phosphorescent compound Also called.) is preferably used. Moreover, a plurality of types of luminescent dopants may be contained, and for example, a combination of dopants having different structures or a combination of a fluorescent dopant and a phosphorescent dopant may be used. This makes it possible to obtain an arbitrary emission color.

Taking the total weight of polymer, host compound and emissive dopant as 100, the weight ratio of emissive dopant can be arbitrarily determined based on the particular dopant used and the requirements of the device. may be uniform or may have an arbitrary distribution in the layer thickness direction.

Since a luminescent dopant loses its luminescent function when it reacts with oxygen or water, it is necessary to make contact with oxygen or water in the atmosphere difficult during production in the atmosphere. In the present invention, contact is made difficult by adjusting the polymer ratio P within a range, and the mass ratio of the luminescent dopant is preferably 30% or less.

(Fluorescent dopant)
The fluorescent dopant is a compound capable of emitting light from an excited singlet, and is not particularly limited as long as light emission from an excited singlet can be observed.

Examples of fluorescent dopants include anthracene derivatives, pyrene derivatives, chrysene derivatives, fluoranthene derivatives, perylene derivatives, fluorene derivatives, arylacetylene derivatives, styrylarylene derivatives, styrylamine derivatives, arylamine derivatives, boron complexes, coumarin derivatives, Examples include pyran derivatives, cyanine derivatives, croconium derivatives, squalium derivatives, oxobenthracene derivatives, fluorescein derivatives, rhodamine derivatives, pyrylium derivatives, perylene derivatives, polythiophene derivatives, rare earth complex compounds, and the like.

(phosphorescent dopant)
The phosphorescent dopant is a compound in which emission from excited triplet is observed. Specifically, it is a compound that emits phosphorescence at room temperature (25°C), and has a phosphorescence quantum yield of 0 at 25°C. .01 or higher. The phosphorescent dopant used in the light-emitting layer preferably has a phosphorescence quantum yield of 0.1 or more.

The phosphorescence quantum yield can be measured by the method described in Experimental Chemistry Course 7, 4th edition, Spectroscopy II, page 398 (1992 edition, Maruzen). Phosphorescence quantum yield in solution can be measured using various solvents. The phosphorescence-emitting dopant used in the light-emitting layer should achieve the phosphorescence quantum yield (0.01 or more) in any solvent.

The phosphorescent dopant can be appropriately selected from known materials used in the light-emitting layer of organic EL devices and used. Specific examples of known phosphorescent dopants that can be used in the present invention include the compounds described in the following documents.

Nature 395, 151 (1998), Appl. Phys. Lett. 78, 1622 (2001), Adv. Mater. 19, 739 (2007), Chem. Mater. 17, 3532 (2005), Adv. Mater. 17, 1059 (2005), WO 2009/100991, WO 2008/101842, WO 2003/040257, U.S. Patent Application Publication No. 2006/835469, U.S. Patent Application Publication No. 2006/ 0202194, US Patent Application Publication No. 2007/0087321, US Patent Application Publication No. 2005/0244673, Inorg. Chem. 40, 1704 (2001), Chem. Mater. 16, 2480 (2004), Adv. Mater. 16, 2003 (2004), Angew. Chem. lnt. Ed. 2006, 45, 7800, Appl. Phys. Lett. 86, 153505 (2005), Chem. Lett. 34, 592 (2005), Chem. Commun. 2906 (2005), Inorg. Chem. 42, 1248 (2003), WO 2009/050290, WO 2002/015645, WO 2009/000673, US 2002/0034656, US 7332232 , US2009/0108737, US2009/0039776, US6921915, US6687266, US2007/0190359 Specification, US Patent Application Publication No. 2006/0008670, US Patent Application Publication No. 2009/0165846, US Patent Application Publication No. 2008/0015355, US Patent No. 7250226, US Patent No. 7396598, US2006/0263635, US2003/0138657, US2003/0152802, US7090928, Angew . Chem. lnt. Ed. 47, 1 (2008), Chem. Mater. 18, 5119 (2006), Inorg. Chem. 46, 4308 (2007), Organometallics 23, 3745 (2004), Appl. Phys. Lett. 74, 1361 (1999), WO 2002/002714, WO 2006/009024, WO 2006/056418, WO 2005/019373, WO 2005/123873, WO 2005/123873 2005/123873, WO2007/004380, WO2006/082742, US2006/0251923, US2005/0260441, US7393599 Specification, US7534505, US7445855, US2007/0190359, US2008/0297033, US7338722 , US2002/0134984, US7279704, US2006/098120, US2006/103874, WO2005/ 076380, WO 2010/032663, WO 2008140115, WO 2007/052431, WO 2011/134013, WO 2011/157339, WO 2010/086089, International Publication No. 2009/113646, WO 2012/020327, WO 2011/051404, WO 2011/004639, WO 2011/073149, US Patent Application Publication No. 2012/228583 , US Patent Application Publication No. 2012/212126, JP 2012-069737, JP 2012-195554, JP 2009-114086, JP 2003-81988, JP 2002-302671 Japanese Patent Application Laid-Open No. 2002-363552.

Among them, preferred phosphorescent dopants include organometallic complexes having Ir as a central metal. Complexes containing at least one coordination mode of metal-carbon bond, metal-nitrogen bond, metal-oxygen bond, and metal-sulfur bond are more preferred.

(Delayed fluorescence compound)
[Excited triplet-triplet annihilation (TTA) delayed fluorescence compound]
A luminescence method using delayed fluorescence has emerged to solve the problems of fluorescent compounds. The TTA method originating from collisions between triplet excitons can be described by the following general formula. That is, conventionally, exciton energy is converted only to heat by non-radiative deactivation, but some of the triplet excitons have the advantage of being able to reverse intersystem crossover to singlet excitons that can contribute to light emission. In actual organic EL devices, it is possible to obtain an external extraction quantum efficiency approximately double that of conventional fluorescent light emitting devices.

General formula: T ^* +T ^* →S ^* +S (Wherein, T ^* represents a triplet exciton, S ^* represents a singlet exciton, and S represents a ground state molecule.)
However, as can be seen from the above equation, only one singlet exciton that can be used for light emission is generated from two triplet excitons, so in principle it is impossible to obtain 100% internal quantum efficiency with this method.

[Thermal activated delayed fluorescence (TADF) compound]
The TADF method, which is another high-efficiency fluorescence emission method, is a method that can solve the problems of TTA.

Fluorescent compounds have the advantage that they can be designed indefinitely as described above. That is, among molecularly designed compounds, there are compounds in which the energy level difference between the triplet excited state and the singlet excited state (hereinafter, appropriately abbreviated as " _ΔEST ") is extremely close. do.

Such a compound does not have a heavy atom in the molecule, but reverse intersystem crossing from a triplet excited state to a singlet excited state, which cannot normally occur due to a small _ΔEST , occurs. Furthermore, since the rate constant of deactivation (= fluorescence emission) from the singlet excited state to the ground state is extremely large, the triplet exciton itself is thermally deactivated to the ground state (non-radiative deactivation). It is kinetically advantageous to return to the ground state while emitting fluorescence via the singlet excited state. Therefore, TADF theoretically enables 100% fluorescence emission.

As a fluorescent dopant, examples of compounds that emit delayed fluorescence (delayed fluorescence-emitting compounds and thermally activated delayed fluorescence compounds) include International Publication No. 2011/156793, JP-A-2011-213643, and JP-A-2010. -93181, Japanese Patent No. 5366106, International Publication No. 2013/161437, International Publication No. 2016/158540, etc., but the present invention is not limited thereto.

Further, in the present invention, a quantum dot-containing organic light-emitting device (QD-OLED) can be used as the light-emitting device contained in the light-emitting layer. The configurations described in JP-A-2014-078381, JP-A-2017-101128, and the like can be referred to.

Further, as an inorganic light emitting device (QLED) containing quantum dots, for example, the contents described in JP-A-2015-156367 and JP-A-2018-078279 can be referred to.

Furthermore, the light-emitting layer according to the present invention may be a layer containing a perovskite compound.

In the present invention, "perovskite compound" means a compound having a perovskite structure. The perovskite compound is preferably a perovskite compound in which an organic substance and an inorganic substance are constituent elements of the perovskite structure (a perovskite compound with an organic-inorganic hybrid structure).

In the present invention, the perovskite compound preferably has a structure represented by the following general formula (a) from the viewpoint of photoelectric conversion efficiency.

General formula (a): RMX
In the above general formula (a), R represents an organic molecule. M represents a metal atom. X represents a halogen atom or a chalcogen atom.

In the above general formula (a), R is an organic molecule, preferably a molecule represented by C1NmXn ( _l , _m and _n all represent positive integers).

R is specifically methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, trimethylamine, triethylamine, tripropylamine, tributylamine, tripentylamine, trihexylamine, ethylmethylamine, methylpropylamine, butylmethylamine, methylpentylamine, hexylmethylamine, ethylpropylamine, ethylbutylamine, imidazole, azole, pyrrole, aziridine, azirine, azetidine, Azeto, imidazoline, carbazole and their ions (eg, methylammonium (CH ₃ NH ₃ ), etc.), phenethylammonium, and the like. Among them, methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, their ions and phenethylammonium are preferred, and methylamine, ethylamine, propylamine and their ions are more preferred.

M is a metal atom such as lead, tin, zinc, titanium, antimony, bismuth, nickel, iron, cobalt, silver, copper, gallium, germanium, magnesium, calcium, indium, aluminum, manganese, chromium, molybdenum, europium, etc. mentioned. These elements may be used alone, or two or more of them may be used in combination.

X is a halogen atom or a chalcogen atom such as chlorine, bromine, iodine, sulfur and selenium. These elements may be used alone, or two or more of them may be used in combination. Among them, the halogen atom is preferable because the perovskite compound becomes soluble in an organic solvent by containing a halogen atom in the structure, and application to inexpensive printing methods and the like becomes possible. Furthermore, iodine is more preferable because it narrows the energy bandgap of the organic-inorganic perovskite compound.

Specific examples of the luminescent dopant that can be suitably used in the present invention are shown below, but the present invention is not limited to these.

(Charge carrier transport layer)
A “charge carrier transport layer (also referred to as a “charge transport layer”)” refers to a layer containing a compound having the function of transporting charge carriers, ie, electrons or holes.
In the following, the charge carrier transport layer (“charge transport layer”) is divided into an “electron transport layer” and a “hole transport layer” for explanation.

[Electron transport layer]
The "electron transport layer" is made of a material having a function of transporting electrons, and in a broad sense, an electron injection layer is also included in the electron transport layer. The electron transport layer can be provided as a single layer or multiple layers.

Also, the electron transport layer is preferably formed using a coating liquid containing an electron transport material described below. Moreover, the coating liquid preferably contains the polar fluorinated solvent. The solubility in the polar fluorinated solvent is preferably lower in the order of the material of the electron transport layer, the material of the insulating layer, and the material of the light emitting layer.

Conventionally, the electron transporting material used for the electron transporting layer (the electron transporting layer adjacent to the cathode side in the case of multiple layers) should have the function of transmitting electrons injected from the cathode to the light emitting layer. Any compound can be selected and used from conventionally known compounds. Examples include metal complexes such as fluorene derivatives, carbazole derivatives, azacarbazole derivatives, oxadiazole derivatives, triazole derivatives, silole derivatives, pyridine derivatives, pyrimidine derivatives and 8-quinolinol derivatives.

In addition, metal-free or metal phthalocyanines, or those whose terminals are substituted with alkyl groups, sulfonic acid groups, or the like can also be preferably used as electron transport materials.

Among these, carbazole derivatives, azacarbazole derivatives, pyridine derivatives and the like are preferred in the present invention, and azacarbazole derivatives are more preferred.

The electron transport layer can be formed as a thin film from the electron transport material by a known method such as a spin coating method, a casting method, a printing method including an inkjet printing method, or an LB method. It can be formed by a wet process using a coating liquid containing a transport material and a fluorinated alcohol solvent.

The layer thickness of the electron-transporting layer is not particularly limited, but is usually about 5 nm to 5 μm, preferably 5 to 200 nm. The electron transport layer may have a single layer structure composed of one or more of the above materials.

In addition to the electron transport material, an electron transport layer having a high n property doped with an impurity as a guest material can also be used. Examples thereof include JP-A-4-297076, JP-A-10-270172, JP-A-2000-196140, JP-A-2001-102175, J. Am. Appl. Phys. , 95, 5773 (2004).

The electron transport layer in the invention preferably contains an alkali metal salt of an organic substance. Although there are no particular restrictions on the type of organic matter, formate, acetate, propionic acid, butyrate, valerate, caproate, enanthate, caprylate, oxalate, malonate, and succinate , benzoate, phthalate, isophthalate, terephthalate, salicylate, pyruvate, lactate, malate, adipate, mesylate, tosylate, benzenesulfonate. , preferably formate, acetate, propionate, butyrate, valerate, caproate, enanthate, caprylate, oxalate, malonate, succinate, benzoate, more preferably is preferably an alkali metal salt of an aliphatic carboxylic acid such as formate, acetate, propionate or butyrate, and the aliphatic carboxylic acid preferably has 4 or less carbon atoms. Acetate is most preferred.

The type of alkali metal in the alkali metal salt of the organic substance is not particularly limited, but includes Na, K, Cs and Li, preferably K and Cs, more preferably Cs. Examples of the alkali metal salts of organic substances include combinations of the above organic substances and alkali metals, preferably Li formate, K formate, Na formate, Cs formate, Li acetate, K acetate, Na acetate, Cs acetate, Li propionate, Sodium propionate, K propionate, Cs propionate, Li oxalate, Na oxalate, K oxalate, Cs oxalate, Li malonate, Na malonate, K malonate, Cs malonate, Li succinate, succinic acid Na, K succinate, Cs succinate, Li benzoate, Na benzoate, K benzoate, Cs benzoate, more preferably Li acetate, K acetate, Na acetate, Cs acetate, most preferably Cs acetate.

The content of these dopants is preferably 1.5 to 35% by weight, more preferably 3 to 25% by weight, most preferably 5 to 15% by weight, based on the electron transport layer to which they are added.

Specific examples of known electron-transporting materials suitable for use in the organic EL device of the present invention include the compounds described in the following documents, but the present invention is not limited thereto.

US6528187, US7230107, US2005/0025993, US2004/0036077, US2009/0115316 , U.S. Patent Application Publication No. 2009/0101870, U.S. Patent Application Publication No. 2009/0179554, WO 2003/060956, WO 2008/132085, Appl. Phys. Lett. 75, 4 (1999), Appl. Phys. Lett. 79, 449 (2001), Appl. Phys. Lett. 81, 162 (2002), Appl. Phys. Lett. 81, 162 (2002), Appl. Phys. Lett. 79, 156 (2001), US Pat. , International Publication No. 2006/067931, International Publication No. 2007/086552, International Publication No. 2008/114690, International Publication No. 2009/069442, International Publication No. 2009/066779, International Publication No. 2009/054253, International Publication No. 2011/086935, WO 2010/150593, WO 2010/047707, EP 2311826, JP 2010-251675, JP 2009-209133, JP 2009 -124114, JP 2008-277810, JP 2006-156445, JP 2005-340122, JP 2003-45662, JP 2003-31367, JP 2003-282270 No. 2012/115034, and the like.

[Hole transport layer]
The hole transport layer is composed of a hole transport material having a function of transporting holes, and in a broad sense, a hole injection layer and an electron blocking layer are also included in the hole transport layer. Also, the hole transport layer can be provided as a single layer or a plurality of layers.

The hole transport material has either hole injection or transport or electron blocking properties, and may be either organic or inorganic. For example, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, Examples include stilbene derivatives, silazane derivatives, aniline copolymers, conductive polymer oligomers and thiophene oligomers.

As the hole transport material, those mentioned above can be used, and porphyrin compounds, aromatic tertiary amine compounds and styrylamine compounds can be used, and aromatic tertiary amine compounds can be used in particular. preferable.

Representative examples of aromatic tertiary amine compounds and styrylamine compounds include N,N,N',N'-tetraphenyl-4,4'-diaminophenyl, N,N'-diphenyl-N,N'- Bis(3-methylphenyl)-[1,1′-biphenyl]-4,4′-diamine (abbreviation: TPD), 2,2-bis(4-di-p-tolylaminophenyl)propane, 1,1 -bis(4-di-p-tolylaminophenyl)cyclohexane, N,N,N',N'-tetra-p-tolyl-4,4'-diaminobiphenyl, 1,1-bis(4-di-p -tolylaminophenyl)-4-phenylcyclohexane, bis(4-dimethylamino-2-methylphenyl)phenylmethane, bis(4-di-p-tolylaminophenyl)phenylmethane, N,N'-diphenyl-N, N'-di(4-methoxyphenyl)-4,4'-diaminobiphenyl, N,N,N',N'-tetraphenyl-4,4'-diaminodiphenyl ether, 4,4'-bis(diphenylamino) quadriphenyl, N,N,N-tri(p-tolyl)amine, 4-(di-p-tolylamino)-4'-[4-(di-p-tolylamino)styryl]stilbene, 4-N,N -diphenylamino-(2-diphenylvinyl)benzene, 3-methoxy-4'-N,N-diphenylaminostilbenzene and N-phenylcarbazole. Furthermore, those having two condensed aromatic rings in the molecule described in US Pat. No. 5,061,569, such as 4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPD), 4,4′,4″-tris[N-(3-methylphenyl) in which three triphenylamine units are linked in a starburst configuration described in JP-A-4-308688. -N-phenylamino]triphenylamine (abbreviation: MTDATA) and the like.

Furthermore, polymer materials in which these materials are introduced into the polymer chain or these materials are used as the main chain of the polymer can also be used. Inorganic compounds such as p-type-Si and p-type-SiC can also be used as hole-injecting materials and hole-transporting materials.

Also, Japanese Patent Application Laid-Open No. 11-251067, J. Am. Huang et. al. , Applied Physics Letters, 80 (2002), p. 139, so-called p-type hole transport materials can also be used. In the present invention, these materials are preferably used from the viewpoint of obtaining a light-emitting device with higher efficiency.

The hole-transporting layer is formed by applying the hole-transporting material, for example, a vacuum vapor deposition method, a spin coating method, a casting method, a printing method including an inkjet printing method, and a known method such as the LB method (Langmuir Blodgett method). It can be formed by thinning according to the method. The layer thickness of the hole-transporting layer is not particularly limited, but is usually in the range of about 5 nm to 5 μm, preferably 5 to 200 nm. The hole transport layer may have a single-layer structure composed of one or more of the above materials.

Further, the p-property can be increased by doping the material of the hole transport layer with impurities. Examples thereof include JP-A-4-297076, JP-A-2000-196140, JP-A-2001-102175 and J. Am. Appl. Phys. , 95, 5773 (2004).

Thus, it is preferable to increase the p-property of the hole-transporting layer, since a device with lower power consumption can be produced.

[Electron blocking layer]
The electron blocking layer has the function of a hole transport layer in a broad sense. The electron-blocking layer is made of a material that has the function of transporting holes but has a significantly low ability to transport electrons. By blocking electrons while transporting holes, the probability of recombination between electrons and holes is improved. can be made
Moreover, the structure of a hole transport layer can be used as an electron blocking layer as needed. The layer thickness of the hole blocking layer applied to the present invention is preferably in the range of 3 to 100 nm, more preferably in the range of 5 to 30 nm.

(Charge carrier injection layer: charge injection layer)
A "charge carrier injection layer (hereinafter also referred to as a "charge injection layer")" refers to a layer containing a compound having the function of injecting charge carriers, ie, electrons or holes.
In the following description, the charge carrier injection layer (“charge injection layer”) is divided into a “hole injection layer” and an “electron injection layer”.

The charge injection layer (hole injection layer and electron injection layer) is a layer for injecting charge carriers, that is, electrons or holes, provided between the electrode and the light emitting layer in order to reduce the driving voltage and improve the luminance of the emitted light. The details are described in "Organic EL element and its industrial front" (published by NTS on November 30, 1998), Part 2, Chapter 2, "Electrode materials" (pp. 123-166). , a hole-injection layer and an electron-injection layer.

A charge injection layer can be provided as needed. A hole-injecting layer may be present between the anode and the light-emitting layer or the hole-transporting layer, and an electron-injecting layer may be present between the cathode and the light-emitting layer or the electron-transporting layer.

The "hole injection layer" is described in detail in JP-A-9-45479, JP-A-9-260062, JP-A-8-288069, etc. Specific examples thereof include phthalocyanines represented by copper phthalocyanine. layers, oxide layers typified by vanadium oxide, amorphous carbon layers, and polymer layers using conductive polymers such as polyaniline (emeraldine) and polythiophene.

The "electron injection layer" is described in detail in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, etc., and is specifically typified by strontium, aluminum, and the like. A metal layer, an alkali metal halide layer typified by potassium fluoride, an alkaline earth metal compound layer typified by magnesium fluoride, an oxide layer typified by molybdenum oxide, and the like can be used. In the present invention, the electron injection layer is desirably a very thin film, and although it depends on the constituent materials, the layer thickness is preferably in the range of 1 nm to 10 μm.

(electrode)
[anode]
As the anode in the organic EL element, an electrode material having a large work function (4 eV or more), a metal, an alloy, an electrically conductive compound, or a mixture thereof is preferably used. Specific examples of such electrode materials include metals such as Au, and conductive transparent materials such as CuI, indium tin oxide (ITO), SnO ₂ , ZnO, and IZO. A material such as IDIXO (In ₂ O ₃ —ZnO) that is amorphous and capable of forming a transparent conductive film may also be used. The anode may be formed by forming a thin film of these electrode substances by a method such as vapor deposition or sputtering, and forming a pattern of a desired shape by photolithography. A pattern may be formed through a mask having a desired shape during vapor deposition or sputtering of the electrode material. In the case of using a coatable substance such as an organic conductive compound, a wet film-forming method such as a printing method or a coating method may be used. When emitting light from the anode, the transmittance is desirably greater than 10%, and the sheet resistance of the anode is preferably several hundred Ω/□ or less. Furthermore, although the film thickness depends on the material, it is usually selected within the range of 10 to 1000 nm, preferably within the range of 10 to 200 nm.

[cathode]
On the other hand, as the cathode, a metal having a small work function (4 eV or less) (referred to as an electron-injecting metal), an alloy, an electrically conductive compound, or a mixture thereof is used as an electrode material. Specific examples of such electrode materials include sodium, sodium-potassium alloys, magnesium, lithium, magnesium/copper mixtures, magnesium/silver mixtures, magnesium/aluminum mixtures, magnesium/indium mixtures, aluminum/aluminum oxide (Al ₂ O ₃ ) mixtures, silver, indium, lithium/aluminum mixtures, rare earth metals and the like. Among these, mixtures of electron-injecting metals and second metals, which are stable metals having a higher work function value, such as magnesium/silver mixtures, from the viewpoint of electron-injecting properties and durability against oxidation, Magnesium/aluminum mixtures, magnesium/indium mixtures, aluminum/aluminum oxide (Al ₂ O ₃ ) mixtures, lithium/aluminum mixtures, silver, aluminum and the like are suitable. The cathode can be produced by forming a thin film of these electrode substances by a method such as vapor deposition or sputtering. Moreover, the sheet resistance of the cathode is preferably several hundred Ω/□ or less, and the film thickness is usually selected within the range of 10 nm to 5 μm, preferably within the range of 50 to 200 nm. In order to transmit the emitted light, it is convenient if either the anode or the cathode of the organic EL element is transparent or semi-transparent because the luminance of the emitted light is improved.

In addition, a transparent or translucent cathode can be produced by forming the above metal on the cathode with a film thickness of 1 to 20 nm and then forming the conductive transparent material mentioned in the explanation of the anode thereon. By applying this, it is possible to fabricate a device in which both the anode and the cathode are transparent.

(1.1.2) (Constituent elements of non-luminescence image display unit)
[Insulating layer]
The organic EL element of the present invention has an image display portion composed of a “luminescence image display portion” and a “non-luminescence image display portion”. It is a part other than the "image display part". That is, the organic EL element of the present invention has a form in which a luminescence image display portion in which luminescence pixels are arranged in dots is provided between a plurality of non-luminescence image display portions included in the image display portion. is preferred. Since the non-light-emitting image display portion is a non-light-emitting portion, partition walls (hereinafter also referred to as "banks") functioning as an electrically insulating layer and ink containing a light-emitting material are permeated. It is preferable that the non-insulating ink-receiving layer portion functions as a partition wall (insulating layer).

The term “insulating” refers to a property in which electrons and holes are difficult to move, that is, it is difficult to ^conduct electricity. A property that is In other words, it refers to the property that the electrical conductivity is less than 1E-5 S/m. As the electric resistivity, a value obtained under conditions conforming to JIS-K-6911 by a constant voltage application/leakage current measurement method using a double ring electrode is used.

As an embodiment of the organic EL element of the present invention, a bank may be formed in advance, or after forming an insulating layer uniformly, a light-emitting layer is formed by ink-jetting separately, and spontaneously Banks may be formed, but the former method is preferred.

In the present invention, it is a preferred embodiment to form a bank as an insulating layer on the substrate surface. By forming a bank in advance on the periphery of the region for forming each layer, it is possible to prevent the material used for forming each layer from flowing out of the region and to define the polymer ratio. In addition, electrons and holes cannot enter the bank because the bank is insulating, and easily enter the light-emitting layer.

FIG. 3 is a cross-sectional view showing an example of a substrate having banks. The regions of the surface of the substrate 1 delimited by the banks 2 are bank depressions 2a, and the bank surfaces are bank projections 2b. A light-emitting image display portion according to the present invention is formed in the concave portion 2a.

The height of the bank is not particularly limited as long as it is possible to prevent outflow of ink or the like, but it is preferably in the range of 1.1 to 2.5 μm. A more preferred range is 1.5 to 2.5 μm. In addition to the trapezoidal shape illustrated in FIG. 3, banks of various shapes can be applied according to the intended effect.

(insulating material)
A known material can be used for the material of the insulating layer (bank) according to the present invention. preferable. By having at least one organic group other than an alkyl group in the polysiloxane structure, it is possible to obtain a light-emitting image display portion having excellent solvent resistance and peeling resistance.

(Organic-inorganic hybrid polymer structure)
As the organic group other than the alkyl group of the organic-inorganic hybrid polymer used in the present invention, known substituents can be used without particular limitation. Cyano group, nitro group, nitroso group, azo group, diazo group, azide group, carbonyl group, phenyl group, hydroxy group, peroxy group, acyl group, acetyl group, aldehyde group, carboxy group, amide group, imide group, ester group , oxime group, thiol group, sulfo group, urea group, isonitrile group, allene group, acryloyl group, methacryloyl group, epoxy group, oxetane group, isocyanate group and the like can be used. Acryloyl groups, epoxy groups or isocyanate groups are preferred. Among them, an acryloyl group is particularly preferred.

(polysiloxane structure)
Examples of polysiloxane structures include polysiloxanes (including polysilsesquioxanes) having Si—O—Si bonds. Specifically, polysiloxane can include [R ₃ SiO _1/2 ], [R ₂ SiO], [RSiO _3/2 ] and [SiO ₂ ] as general structural units. Here, R is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms (e.g., methyl group (Me), ethyl group, propyl group, etc.), an aryl group (e.g., phenyl group (Ph), etc.), unsaturated alkyl independently selected from the group consisting of groups (eg, vinyl groups, etc.); Examples of specific polysiloxane structures include [PhSiO _3/2 ], [MeSiO _3/2 ], [HSiO _3/2 ], [MePhSiO], [Ph ₂ SiO], [PhViSiO], [ViSiO _3/2 ] (Vi represents a vinyl group), [MeHSiO], [MeViSiO], [Me ₂ SiO], [Me ₃ SiO _1/2 ] and the like. Mixtures and copolymers of polysiloxanes can also be used.

(binder resin)
In the insulating layer, in addition to the organic-inorganic hybrid polymer used in the present invention, a binder resin can be used within a range that does not impair the effects of the present invention.
Examples of binder resins include cellulose derivatives such as cellulose diacetate, cellulose triacetate, cellulose acetate butyrate, cellulose acetate phthalate, and cellulose nitrate, polyvinyl acetate, polystyrene, polycarbonate, polybutylene terephthalate, copolybutylene/tere/isophthalate, and the like. polyester, polyvinyl alcohol, polyvinyl formal, polyvinyl acetal, polyvinyl butyral, polyvinyl alcohol derivatives such as polyvinyl benzal, norbornene-based polymers containing norbornene compounds, polymethyl methacrylate, polyethyl methacrylate, polypropylethyl methacrylate, polybutyl methacrylate, poly Acrylic resins such as methyl acrylate or copolymers of acrylic resins and other resins can be used, but the material is not particularly limited to these exemplified resin materials. Among these, cellulose derivatives and acrylic resins are preferred, and acrylic resins are most preferred.

(insulating metal oxide)
As a material for the insulating layer, it is also preferable to contain an insulating metal oxide in the binder resin.

Although the insulating metal oxide is not particularly limited, alumina, zirconia, titania, silica, magnesia, or niobium is preferable from the viewpoint of chemical stability and physical stability. Specifically, titanium oxide, zirconium oxide, tantalum oxide, solid solution of zirconium oxide and silicon oxide, silicon oxide, aluminum oxide, zinc oxide, magnesium oxide, niobium oxide, bismuth oxide, copper oxide, tin oxide, hafnium oxide. or hydrates of these metal oxides, barium titanate, barium zirconate, potassium niobate, sodium niobate, calcium titanate, strontium tantalate, bismuth titanate, bismuth sodium titanate, or these An insulating solid solution containing at least one of them in its composition can be exemplified.

Among them, metal oxides having a dielectric constant of 100 or more are preferable, and examples thereof include rutile-type titanium oxide (TiO ₂ ), zirconium oxide (ZrO), niobium pentoxide (Nb ₂ O ₃ ), and titanic acid. Barium (BaTiO ₃ ), strontium titanate (SrTiO ₃ ), lead titanate (PbTiO ₃ ), barium zirconate titanate (BaTi _0.5 Zr _0.5 O ₃ ), lead zirconate titanate (PbTi 0.5 ) _{. 5 Zr 0.5 O 3} ) or the like _, or water thereof hydrates, and insulating solid solutions containing at least one of these in the composition.

In the insulating layer, the bank may be formed in advance, or after forming the insulating layer uniformly, the light-emitting layer may be formed by ink jetting separately, and the bank may be spontaneously formed. . When patterning the bank in advance, the insulating layer is formed, for example, by the following method.

As a substrate, a 0.5 mm glass substrate (Eagle XG manufactured by Corning) was washed with an alkali, and then a photosensitive polyimide containing 30% by mass of titanium oxide (manufactured by Merck) was applied by spin coating, and the temperature was kept at 60°C. is pre-baked for 120 seconds. Next, pattern exposure is performed by a photo process, development is performed with tetramethylammonium hydroxide (abbreviation: TMAH), and rinsing with pure water is performed to form banks having openings.

(polar fluorinated solvent)
In the method for producing an organic EL element of the present invention, it is preferable to use a polar fluorinated solvent for forming the insulating layer. A polar fluorinated solvent is also preferably used for forming an electron transport layer, which will be described later.

Here, the polar fluorinated solvent is a solvent that contains a fluorine atom in the solvent molecule, has a dielectric constant of 3 or more, and has a solubility in water of 5 g/L or more at 25°C.

The boiling point of the polar fluorinated solvent is preferably within the range of 50 to 200°C. By setting the temperature to 50° C. or higher, it is possible to more reliably suppress the occurrence of unevenness due to heat of evaporation during drying of the coating film. By setting the temperature to 200° C. or less, the solvent can be dried quickly, the solvent content in the formed layer is reduced, so that the crystal growth in the layer can be suppressed more reliably, and the solvent escape route is rough. Therefore, the density is improved and the current efficiency can be increased. More preferably, it is within the range of 70 to 150°C.

The water content of the polar fluorinated solvent is preferably as low as possible because even a very small amount of water is a quencher of light emission, preferably 100 ppm or less, more preferably 20 ppm or less.

Similarly, the content of impurities other than water in the polar fluorinated solvent is as low as 100 ppm, because even a very small amount can become a quencher of light emission, cause air bubbles, or cause deterioration of the film quality after drying. The following is preferable, and 20 ppm or less is more preferable. Impurities other than water include oxygen, inert gases such as nitrogen, argon and carbon dioxide, and inorganic compounds or metals brought in from catalysts, adsorbents and equipment used during preparation and purification.

As the polar fluorinated solvent, for example, fluorinated alcohols, fluorinated acrylates, fluorinated methacrylates, fluorinated esters, fluorinated ethers or fluorinated hydroxyalkylbenzenes, and fluorinated amines are preferable, and fluorinated alcohols, fluorinated esters or fluorinated Ethers are more preferred, and fluorinated alcohols are even more preferred from the viewpoint of solubility and drying properties.

Also, the number of carbon atoms in the fluorinated alcohol is preferably 3 to 5 from the viewpoint of the boiling point and the solubility of the material.

The fluorine-substituted position is, for example, the position of hydrogen in the case of alcohol, and the fluorination rate is sufficient as long as it does not impair the solubility of the layer material, and is fluorinated to the extent that the lower layer material is not eluted. is desirable.

Examples of fluorinated alcohols include 1H,1H-pentafluoropropanol, 6-(perfluoroethyl)hexanol, 1H,1H-heptafluorobutanol, 2-(perfluorobutyl)ethanol (FBEO), 3-(perfluoro butyl)propanol, 6-(perfluorobutyl)hexanol, 2-perfluoropropoxy-2,3,3,3-tetrafluoropropanol, 2-(perfluorohexyl)ethanol, 3-(perfluorohexyl)propanol, 6 -(perfluorohexyl)hexanol, 1H,1H-(perfluorohexyl)hexanol, 6-(perfluoro-1-methylethyl)hexanol, 1H,1H,3H-tetrafluoropropanol (TFPO), 1H,1H,5H - octafluoropentanol (OFAO), 1H,1H,7H-dodecafluoroheptanol (DFHO), 2H-hexafluoro-2-propanol, 1H,1H,3H-hexafluorobutanol (HFBO), 2,2,3 , 3,4,4,5,5-octafluoro-1,6-hexanediol, 2,2-bis(trifluoromethyl)propanol, 1H,1H-trifluoroethanol (TFEO) and the like. TFPO, OFAO and HFBO are preferred from the viewpoint of the boiling point of and the solubility of the layer material.

Examples of fluorinated ethers include hexafluorodimethyl ether, perfluorodimethoxymethane, perfluorooxetane, perfluoro-1,3-dioxolane, 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetra fluoropropyl ether and the like.

Examples of fluorinated esters include methyl perfluorobutyrate, ethyl perfluorobutyrate, methyl perfluoropropionate, methyl difluoroacetate, ethyl difluoroacetate, methyl-2-trifluoromethyl-3,3,3- and trifluoropropionate.

In the insulating layer-forming coating solution, the content of the insulating compound is preferably 0.05 to 10% by mass, and the content of the polar fluorinated solvent is preferably 90 to 99.95% by mass.

The polar fluorinated solvent may be a mixed solvent of two or more polar fluorinated solvents, or a mixture of a polar fluorinated solvent and a solvent other than a polar fluorinated solvent, as long as it does not dissolve the light-emitting layer material. A solvent may be used. For example, a mixed solvent of fluorinated alcohol and alcohol can be used. When using a mixed solvent, the content of the polar fluorinated solvent is preferably 50% by mass or more.

(1.1.3) Other Common Elements Hereinafter, common elements related to both the light emitting image display section and the non-light emitting image display section will be described.

[substrate]
The material of the substrate used in the organic EL element is not particularly limited, and preferable examples include glass, quartz, resin film, and the like. Particularly preferred is a resin film that imparts flexibility to the organic EL element and can be embedded in a printed matter or the like.

Examples of resin films include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate (TAC), cellulose acetate butyrate, cellulose acetate propionate ( CAP), cellulose esters such as cellulose acetate phthalate, cellulose nitrate, or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyether ketone, polyimide or Films such as cycloolefin resins such as APEL (trade name, manufactured by Mitsui Chemicals, Inc.) can be mentioned.

A gas barrier film may be formed on the surface of the resin film by a coating of an inorganic substance, an organic substance, or a hybrid coating of both. The gas barrier film has a water vapor permeability (25±0.5°C, humidity (90±2)% RH) measured by a method conforming to JIS K 7129-1992 of 0.01 g/(m ² 24 h) or less. is preferably a gas barrier film. Furthermore, the oxygen permeability measured by a method based on JIS K 7126-1987 is 1 × 10 ^-3 mL / (m ² · 24 h · atm) or less, and the water vapor permeability is 1 × 10 ^-5 g / It is preferably a high gas barrier film of (m ² ·24 h) or less.

As a material for forming the gas barrier film, any material can be used as long as it has a function of suppressing penetration of moisture, oxygen, and the like. For example, silicon oxide, silicon dioxide, silicon nitride, etc. can be used. Furthermore, in order to improve the fragility of the gas barrier film, it is more preferable to have a laminated structure of these inorganic layers and layers made of organic materials. The order of lamination of the inorganic layer and the organic layer is not particularly limited, but it is preferable to alternately laminate the two layers a plurality of times.

The method for forming the gas barrier film is not particularly limited. A method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or the like can be used. For example, atmospheric pressure plasma polymerization as described in JP-A-2004-68143 is preferred.

[Sealing]
As a sealing means used for sealing the organic EL element of the present invention, for example, a method of adhering a sealing member, an electrode, and a supporting substrate with an adhesive can be mentioned.

The sealing member may be arranged so as to cover the display area of the organic EL element, and may be in the form of a concave plate or a flat plate. Moreover, transparency and electric insulation are not particularly limited.

Specifically, glass plates, polymer plates/films, metal plates/films, and the like can be mentioned. Examples of glass plates include soda-lime glass, barium-strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, and quartz. Further, examples of the polymer plate include polycarbonate, acryl, polyethylene terephthalate, polyether sulfide, polysulfone, and the like. Metal plates include those made of one or more metals or alloys selected from the group consisting of stainless steel, iron, copper, aluminum, magnesium, nickel, zinc, chromium, titanium, molybdenum, silicon, germanium and tantalum.

In the present invention, a polymer film or a metal film can be preferably used since the organic EL device can be made thinner. Furthermore, the polymer film preferably has an oxygen permeability of 10 ⁻³ g/(m ² ·24 h) or less and a water vapor permeability of 10 ⁻³ g/(m ² ·24 h) or less. Further, it is more preferable that both the water vapor permeability and the oxygen permeability are 10 ⁻⁵ g/(m ² ·24 h) or less.

Sandblasting, chemical etching, or the like is used to process the sealing member into a concave shape. Specific examples of adhesives include photocurable and heat-curable adhesives having reactive vinyl groups of acrylic acid-based oligomers and methacrylic acid-based oligomers, and moisture-curable adhesives such as 2-cyanoacrylic acid esters. be able to. Thermal and chemical curing types (two-liquid mixture) such as epoxies can also be mentioned. Hot-melt type polyamides, polyesters and polyolefins can also be mentioned. Further, a cationic curing type ultraviolet curing type epoxy resin adhesive can be mentioned.

A desiccant may be dispersed in the adhesive. A commercially available dispenser may be used to apply the adhesive to the sealing portion, or printing such as screen printing may be used.

Alternatively, the electrode and the organic functional layer may be coated on the outside of the electrode on the side facing the supporting substrate with the organic functional layer interposed therebetween, and inorganic and organic layers may be formed in contact with the supporting substrate to form a sealing film. I can do it well. In this case, the material for forming the film may be any material that has a function of suppressing the infiltration of substances that cause deterioration of the device, such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, and the like can be used. can. Furthermore, in order to improve the brittleness of the film, it is preferable to have a laminated structure of these inorganic layers and layers made of an organic material. The method for forming these films is not particularly limited. A method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or the like can be used.

An inert gas such as nitrogen or argon, or an inert liquid such as fluorocarbon or silicone oil may be injected into the gap between the sealing member and the display area of the organic EL element in the gas phase and the liquid phase. is preferred. A vacuum is also possible. Also, a hygroscopic compound can be sealed inside.

Examples of hygroscopic compounds include metal oxides (e.g. sodium oxide, potassium oxide, calcium oxide, barium oxide, magnesium oxide, aluminum oxide, etc.), sulfates (e.g. sodium sulfate, calcium sulfate, magnesium sulfate, cobalt sulfate etc.), metal halides (e.g. calcium chloride, magnesium chloride, cesium fluoride, tantalum fluoride, cerium bromide, magnesium bromide, barium iodide, magnesium iodide, etc.), perchlorates (e.g. barium perchlorate , magnesium perchlorate, etc.), and anhydrous salts are preferably used for sulfates, metal halides and perchlorates.

[Protective film, protective plate]
A protective film or a protective plate may be provided on the outside of the sealing film or film for sealing on the side facing the support substrate with the organic functional layer interposed therebetween in order to increase the mechanical strength of the device. In particular, when sealing is performed by a sealing film, the mechanical strength thereof is not necessarily high, so it is preferable to provide such a protective film or protective plate. Materials that can be used for this include glass plates, polymer plates/films, metal plates/films, etc. similar to those used for the above sealing. is preferably used.

(others)
[Light extraction improvement technology]
An organic EL element emits light inside a layer with a refractive index higher than that of air (within a refractive index range of about 1.6 to 2.1), and only about 15 to 20% of the light generated in the light emitting layer is emitted. It is generally said that it cannot be taken out.

This is because light incident on the interface (interface between the transparent substrate and the air) at an angle θ greater than the critical angle is totally reflected and cannot be taken out of the element, and the light between the transparent electrode or the light-emitting layer and the transparent substrate cannot be extracted. This is because the light is totally reflected between them, the light is guided through the transparent electrode or the light-emitting layer, and as a result, the light escapes in the lateral direction of the device.

Methods for improving the efficiency of extracting light include, for example, forming irregularities on the surface of the transparent substrate to prevent total reflection at the interface between the transparent substrate and the air (see, for example, US Pat. No. 4,774,435); A method of improving efficiency by providing light-collecting properties (for example, JP-A-63-314795), a method of forming a reflective surface on the side surface of an element (for example, JP-A-1-220394), a substrate A method of forming an antireflection film by introducing a flat layer having an intermediate refractive index between the substrate and the light emitter (for example, Japanese Patent Application Laid-Open No. 62-172691), a lower refractive index than the substrate between the substrate and the light emitter A method of introducing a flat layer having a coefficient (for example, Japanese Patent Laid-Open No. 2001-202827), a method of forming a diffraction grating between any of the substrate, the transparent electrode layer and the light emitting layer (including between the substrate and the outside world) ( JP-A-11-283751) and the like.

In the present invention, these methods can be used in combination with the organic EL device. A method of forming a diffraction grating between layers (including between the substrate and the outside world) between the substrate and the light-emitting layer can be preferably used.

When a medium with a low refractive index is formed with a thickness longer than the wavelength of light between the transparent electrode and the transparent substrate, the light emitted from the transparent electrode is more efficiently extracted to the outside as the refractive index of the medium is lower. Become.

By combining these means, the present invention can obtain an element with even higher luminance or excellent durability.

Examples of low refractive index layers include airgel, porous silica, magnesium fluoride, and fluorine-based polymers. Since the refractive index of the transparent substrate is generally in the range of about 1.5 to 1.7, the low refractive index layer preferably has a refractive index of about 1.5 or less. Further, it is preferably 1.35 or less.

Moreover, it is desirable that the thickness of the low refractive index medium is at least twice the wavelength in the medium. This is because when the thickness of the low-refractive-index medium is about the wavelength of light and reaches a thickness at which the electromagnetic wave seeped out by evanescence penetrates into the substrate, the effect of the low-refractive-index layer is weakened.

The method of introducing a diffraction grating into an interface or any medium that causes total reflection is characterized by a high effect of improving the light extraction efficiency. This method utilizes the property that a diffraction grating can change the direction of light to a specific direction different from refraction by means of so-called Bragg diffraction, such as first-order diffraction and second-order diffraction. Among the emitted light, the light that cannot go out due to total reflection between layers or the like is diffracted by introducing a diffraction grating in one of the layers or in the medium (inside the transparent substrate or in the transparent electrode). , to bring the light out.

The diffraction grating to be introduced preferably has a two-dimensional periodic refractive index. This is because the light emitted from the light-emitting layer is randomly generated in all directions, so a general one-dimensional diffraction grating that has a periodic refractive index distribution in only one direction can only diffract light traveling in a specific direction. Therefore, the light extraction efficiency does not increase so much.

However, by making the refractive index distribution a two-dimensional distribution, light traveling in all directions is diffracted and the light extraction efficiency is increased.

The position where the diffraction grating is introduced may be between any of the layers or in the medium (inside the transparent substrate or in the transparent electrode), but is preferably in the vicinity of the organic light-emitting layer where light is generated. At this time, the period of the diffraction grating is preferably in the range of about 1/2 to 3 times the wavelength of light in the medium. The arrangement of the diffraction gratings is preferably two-dimensionally repeated, such as a square lattice, a triangular lattice, or a honeycomb lattice.

[Condensing sheet]
The organic EL element of the present invention can be obtained by processing the light extraction side of the support substrate (substrate) so as to provide, for example, a microlens array structure, or by combining with a so-called light-condensing sheet. By condensing light in the front direction with respect to the light emitting surface, it is possible to increase the brightness in a specific direction.

As an example of the microlens array, square pyramids each having a side of 30 μm and an apex angle of 90 degrees are arranged two-dimensionally on the light extraction side of the support substrate. One side is preferably within the range of 10 to 100 μm. If it is smaller than this, the effect of diffraction will occur and coloring will occur.

As the condensing sheet, it is possible to use, for example, a material that has been put to practical use in the LED backlight of the liquid crystal display device. For example, a brightness enhancement film (BEF) manufactured by Sumitomo 3M Co., Ltd. can be used as such a sheet. As for the shape of the prism sheet, for example, delta-shaped stripes with a vertical angle of 90 degrees and a pitch of 50 μm may be formed on the substrate, or a shape with rounded vertical angles and a randomly varied pitch may be used. A shape or other shape may be used.

In addition, a light diffusing plate/film may be used together with the condensing sheet in order to control the light emission angle from the organic EL element. For example, a diffusion film (light up) manufactured by Kimoto Co., Ltd. can be used.

(1.2) <<Other configurations of the organic EL element>>
For other outlines of the structure of the organic EL element applicable to the present invention, for example, JP-A-2013-157634, JP-A-2013-168552, JP-A-2013-177361, JP-A-2013-187211 Publications, JP-A-2013-191644, JP-A-2013-191804, JP-A-2013-225678, JP-A-2013-235994, JP-A-2013-243234, JP-A-2013-243236, JP 2013-242366, JP 2013-243371, JP 2013-245179, JP 2014-003249, JP 2014-003299, JP 2014-013910, JP Configurations described in Japanese Unexamined Patent Publication No. 2014-017493, Japanese Unexamined Patent Publication No. 2014-017494, etc. can be mentioned.

Further, as specific examples of the tandem-type organic EL device, for example, US Pat. No. 6,337,492, US Pat. No. 6107734, US Patent No. 6337492, JP 2006-228712, JP 2006-24791, JP 2006-49393, JP 2006-49394, JP 2006- 49396, JP 2011-96679, JP 2005-340187, JP 4711424, JP 3496681, JP 3884564, JP 4213169, JP 2010-192719 Publications, JP 2009-076929, JP 2008-078414, JP 2007-059848, JP 2003-272860, JP 2003-045676, WO 2005/009087, Examples include the device configuration and constituent materials described in International Publication No. WO 2005/094130, etc., but the present invention is not limited thereto.

2 <<Method for manufacturing organic EL element>>
An example of the method for manufacturing the organic EL element of the present invention will be described in detail, taking the case of manufacturing the organic EL element 10 shown in FIG. 2 as an example.

First, the anode 12 is formed on the substrate 11 . Next, a bank 2 is formed on the anode 12, and a hole injection layer 13 and a hole transport layer 14 are formed in this order in the recess 2a of the bank 2. Next, as shown in FIG. Next, the light-emitting layer 15 is formed using the light-emitting layer forming coating solution. Next, an electron transport layer 16 , an electron injection layer 17 and a cathode 18 are formed on the light emitting layer 15 . Anode 12 and cathode 18 form a common electrode for the light emitting layer.
Similarly, blue (B) light-emitting pixels 21, green (G) light-emitting pixels 22, and red (R) light-emitting pixels 23 are formed.
However, in addition to the B, G, and R light-emitting pixels, the light-emitting pixels include four colors (B, G, R, and W (white)), five colors (B, G, R, W (white), and LB). (Mixed color of B and G) and O (Mixed color of G and R) are also preferable, and one or more types of configuration suitable for the image portion can be selected from these emission colors.

Finally, the device after forming the cathode 18 is sealed (not shown). As the sealing means used for sealing the element, known members and methods can be used. The organic EL element 10 can be manufactured as described above.

Incidentally, as a method for forming each layer other than the bank constituting the organic EL element 10, any method such as a wet method, vapor deposition, and sputtering may be used as described above. However, for the light-emitting layer, it is preferable to use a wet method, and particularly preferably to use an inkjet printing method, because deterioration in performance during manufacturing in the air is suppressed and costs are suppressed.

Liquid media used in inkjet printing include, for example, ketones such as methyl ethyl ketone and cyclohexanone, fatty acid esters such as ethyl acetate, isopropyl acetate, propylene glycol monomethyl ether acetate and 3-methoxybutyl acetate, and halogenated solvents such as dichlorobenzene. Hydrocarbons, aromatic hydrocarbons such as toluene, xylene, mesitylene, cyclohexylbenzene, non-fluorinated alcohols such as methanol, ethanol, propanol, isopropanol, trifluoroethanol (TFEO), tetrafluoropropanol (TFPO), hexafluoro Fluorinated alcohols such as fluoropropanol (HFPO), aliphatic hydrocarbons such as cyclohexane, decalin and dodecane, and organic solvents such as DMF and DMSO can be used, but the amount of solvent contained in the element is suppressed. Therefore, a solvent having a boiling point in the range of 50° C. to 180° C. is preferably used. Moreover, as a dispersion method, it can be dispersed by a dispersion method such as ultrasonic wave, high shear force dispersion, media dispersion, or the like.

In the present invention, the solvent content contained in the organic EL device is in the range of 0.01 to 1 μg/cm ² . If the amount is 0.01 μg or less, the organic film becomes sparse, which causes a ^high voltage when the device is driven. Efficiency and low drive life result. These solvent contents can be determined by thermal desorption spectroscopy.

(Inkjet printing method)
The luminescent layer according to the present invention is preferably formed by an inkjet printing method, particularly preferably by an inkjet printing method in the atmosphere. In the case of forming a film by a droplet ejection method such as an inkjet printing method, the effect of the active gas in the film forming atmosphere is more pronounced than in the case of forming a film by vapor deposition or spin coating, resulting in a decrease in luminous efficiency and a short life. However, even in such cases, it emits light without degradation in performance. Therefore, manufacturing in the atmosphere is possible, and manufacturing costs for inert gas and vacuum equipment can be reduced.
The method of forming other layers constituting the organic EL element is not limited, and may be an inkjet printing method or other methods.

The inkjet head used in the inkjet printing method may be of an on-demand system or a continuous system. In addition, as a discharge method, an electro-mechanical conversion method (eg, single cavity type, double cavity type, bender type, piston type, share mode type, shared wall type, etc.), an electro-thermal conversion method (eg, thermal Specific examples include inkjet type, bubble jet (registered trademark) type, etc.), electrostatic attraction type (e.g., electric field control type, slit jet type, etc.), discharge type (e.g., spark jet type, etc.), and the like. However, any ejection method may be used. Moreover, as a printing method, a serial head method, a line head method, or the like can be used without limitation.

The volume of ink droplets ejected from the head is preferably in the range of 0.5 to 100 pL. The range of 2 to 50 pL is more preferable from the viewpoint of reducing coating unevenness and increasing the printing speed. Note that the volume of the ink droplet can be appropriately adjusted by adjusting the applied voltage or the like.

The print resolution is preferably in the range of 180 to 10000 dpi (dots per inch), more preferably in the range of 360 to 2880 dpi, and can be appropriately set in consideration of the wet thickness, ink droplet volume, and the like.

In the present invention, the wet thickness of the wet coating film at the time of inkjet coating (immediately after coating) can be appropriately set, preferably in the range of 1 to 100 μm, more preferably in the range of 1 to 30 μm, most preferably 1 The effects of the present invention are more pronounced in the range of up to 5 μm. The wet thickness can be calculated from the coating area, print resolution, and ink droplet volume.

Inkjet printing methods include a single-pass (one-pass) printing method and a multi-pass printing method. The single-pass printing method is a method of printing a predetermined print area by one head scan. On the other hand, the multi-pass printing method is a method of printing a predetermined print area by multiple head scans.

In the single-pass printing method, it is preferable to use a wide head in which nozzles are arranged over a width equal to or greater than the width of the desired coating pattern. When forming a plurality of independent coating patterns that are not continuous on the same substrate, a wide head that is at least as wide as the width of each coating pattern may be used.

An example of a method for forming an organic functional layer by an inkjet printing method will be described below with reference to the drawings.

FIG. 1 shows a conceptual diagram showing that the luminescent pixels 21 to 23 are arranged in dots when viewed from the direction perpendicular to the surface of the organic EL element 10 . The position of each dot may be in a regular permutation or in a staggered arrangement. Among them, a staggered arrangement is more preferable.

FIG. 4 is a schematic diagram showing an example of a single-pass system (line head system) inkjet recording apparatus applicable to the method for manufacturing an organic EL element of the present invention. In FIG. 4(a), 100 is a line head type head unit, each of which has different hues of ink (for example, inks containing compounds emitting red (R), green (G), and blue (B) colors). ), and the nozzle pitch of each head is preferably about 360 dpi. The dpi referred to in the present invention represents the number of dots per 2.54 cm.
The substrates 1 are fed in the direction of the arrow from the conveying mechanism 101 in a state of being laminated in a roll shape.

FIG. 4B is a bottom view showing the arrangement of nozzles on the bottom of each head. As shown in FIG. 4B, the nozzles N of the heads 102, 103, and 104 are staggered by half a pitch. With such a head structure, a more dense image can be formed.

FIG. 4C is a schematic diagram showing an example of the head unit configuration. When a wide substrate 1 is used, it is also preferable to use a head unit HU in which a plurality of heads H are arranged in a zigzag arrangement so as to cover the entire width of the substrate 1 .

A coating liquid (ink) containing a luminescent dopant, a host compound, etc. for forming a luminescent layer of an organic EL element and a solvent on the substrate 1 while continuously transporting the substrate 1 using the inkjet recording apparatus; Alternatively, a coating liquid (ink) containing an organic functional material and a solvent for forming the organic functional layer is sequentially ejected as ink droplets onto the substrate 1 to form the light-emitting layer and the organic functional layer.

In addition to the inkjet recording apparatus used in the present invention, for example, JP-A-2012-140017, JP-A-2013-010227, JP-A-2014-058171, JP-A-2014-097644, JP-A-2015 -142979, JP 2015-142980, JP 2016-002675, JP 2016-002682, JP 2016-107401, JP 2017-109476, JP 2017-177626 An ink-jet head having a configuration described in JP-A-2003-200053 or the like can be appropriately selected and applied.

3 <<Application>>
(Lighting device)
Since the organic EL element of the embodiment described above is a surface or minute light emitter, it can be used as various light sources. For example, lighting devices such as home lighting and in-vehicle lighting, backlights for clocks and liquid crystals, lighting for billboard advertisements, light sources for traffic lights, light sources for optical storage media, light sources for electrophotographic copiers, light sources for optical communication processors, A light source for an optical sensor and the like can be mentioned.

(Display device; print model)
It is also useful as a color display, taking advantage of its flexibility. In particular, since the organic EL element of the present invention is a simple display device, it can be finely produced according to demand by a two-dimensional inkjet method or a three-dimensional inkjet method. A dimensional model can be provided.

(others)
In addition, the present invention can similarly exhibit functions in organic semiconductor devices that do not emit light and are formed of a polymer and a charge-transporting material, and can be applied to solar cells, photodiodes, various sensors, and the like. For example, in the case of an organic photodiode, a low-conductivity polymer promotes molecular contact and bulk heterostructure formation between an electron-withdrawing material such as fullerene and a photoelectric conversion material such as coumarin 30, and only improves the charge separation ability. Instead, localization of the polymer material in the vicinity of the interface can suppress charge trapping due to oxygen and water.

EXAMPLES The present invention will be specifically described below with reference to Examples, but the present invention is not limited to these. In the examples, "parts" or "%" are used, but "mass parts" or "mass%" are indicated unless otherwise specified.

As for the polymer, the polymer described above was used. For element 102, a polymer represented by structural formula (11) below was used. As host compounds, KH-1, KH-2, KH-12, KH-15 and KH-22 described above were used. As luminescent dopants, RD-3, BD-2, BD-3, BD-4 and BD-5 described above were used.

The following commercial products were used for the polymers (1) to (30). Mw is the weight average molecular weight of each commercial product, and Mn is the number average molecular weight.
(1) Polymethyl methacrylate [Mw: ~120k, manufactured by Sigma-Aldrich]
(2) Polyethylene [Mw: ~4k, manufactured by Sigma-Aldrich]
(3) Polychlorotrifluoroethylene [manufactured by Daikin Industries, Ltd., Polyflon (registered trademark) M-12]
(4) Polyvinylidene fluoride [Mw: 410 to 575, manufactured by Piezotech, Piezotech (registered trademark) RT-TS]
(5) Polyacetal [manufactured by Polyplastics, Duracon (registered trademark) M90-44]
(6) Poly(1,4-butylene terephthalate) [manufactured by Sigma-Aldrich]
(7) Polyethylene terephthalate [manufactured by Sigma-Aldrich]
(8) polyimide [manufactured by DuPont, Vespel (registered trademark) SP-1]
(9) Polyamideimide [manufactured by Solvay, Torlon (registered trademark) 4000TF]
(10) Polyetherimide [manufactured by Sigma-Aldrich, melt index: 18 g/10 min (337° C./6.6 kg)]
(11) Poly(3,4-ethylenedioxythiophene) [manufactured by Sigma-Aldrich, Aedtron C-NM]
(12) Poly(3-hexylthiophene) [Mn: 27k to 45k, manufactured by Tokyo Chemical Industry Co., Ltd.]
(13) Polysulfone [Mn: ~22k, manufactured by Sigma-Aldrich]
(14) Poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene] [Mn: 40k to 70k, manufactured by Sigma-Aldrich]
(15) Acrylonitrile-styrene copolymer [Mw: ~165k, x = 75, y = 25, manufactured by Sigma-Aldrich]
(16) Poly(9-vinylcarbazole) [Mw: ~110k, manufactured by Sigma-Aldrich]
(17) Poly(9,9-dioctylfluorene) [Mw: ~20k, manufactured by Sigma-Aldrich]
(18) Poly(1,4-phenylene sulfide) [Mn: ~10k, manufactured by Sigma-Aldrich]
(19) Poly(9,9-dioctylfluorene-alt-benzothiadiazole) [Mn: ~25k, manufactured by Sigma-Aldrich]
(20) Polycarbonate [manufactured by Sigma-Aldrich, GF65553598]
(21) Poly(2,6-dimethyl-1,4-phenylene oxide) [Mn: 20k, Mw: 30k, manufactured by Sigma-Aldrich]
(22) Poly (4,4′-isopropylidenediphenylene terephthalate) [U-100 manufactured by Unitika Ltd.]
(23) Polyetheretherketone [Mn: ~10.3k, Mw: ~20.8, manufactured by Sigma-Aldrich]
(24) Polymethylstyrene [Mw: ~72k, manufactured by Sigma-Aldrich]
(25) Polystyrene-methyl methacrylate copolymer [Mw: 100k to 150k, x = 40, y = 60, manufactured by Sigma-Aldrich]
(26) Poly(2-vinylpyridine) [Mn: 152k, Mw: 159k, manufactured by Sigma-Aldrich]
(27) Polyethersulfone [manufactured by Sigma-Aldrich]
(28) Polystyrene [Mw: ~280k, manufactured by Sigma-Aldrich]
(29) Poly(4-vinylphenol) [Mw: ~25k, manufactured by Sigma-Aldrich]
(30) Ethylene-tetrafluoroethylene copolymer [Fluon (registered trademark) ETFE manufactured by Asahi Glass Co., Ltd.]

As shown in FIG. 5, an anode 12/light emitting layer 15/electron injection layer 17/cathode 18 are laminated on a substrate 11 and sealed with a sealing layer 30, and a bottom emission type organic EL element 10 is manufactured as follows. It was made as follows.

[Example 1]
<<Production of Organic EL Element 101a>>
(Preparation of substrate)
First, an atmospheric pressure plasma discharge treatment apparatus having the configuration described in Japanese Patent Application Laid-Open No. 2004-68143 was applied to the entire anode forming side of a polyethylene naphthalate film (manufactured by Teijin DuPont, hereinafter abbreviated as "PEN"). was used to form an inorganic gas barrier layer made of silicon oxide (SiOx; 1<x≤4) to a layer thickness of 500 nm. As a result, a flexible substrate having gas barrier properties with an oxygen permeability of 0.001 mL/(m ² ·24 h) or less and a water vapor permeability of 0.001 g/(m ² ·24 h) or less was produced.

(Formation of anode)
An ITO (indium tin oxide) film having an area of 30 mm and a thickness of 120 nm was formed on the substrate by sputtering, and patterned by photolithography to form an anode.

(Formation of insulating layer (bank))
The coating liquid was applied onto the anode prepared above using an inkjet head (MEMS head 1 pL) manufactured by Konica Minolta Co., Ltd. so as to form a square coating pattern of 100 μm on a side at four locations with an interval of 10 μm. Triethylene glycol monobutyl ether was used as the coating liquid.

Then, using an atmospheric pressure plasma discharge treatment apparatus, the substrate coated with the coating liquid was subjected to a lyophilic treatment. Argon gas was used as the discharge gas, and oxygen gas was used as the reactive gas. The power source used for plasma generation was PHF2-K manufactured by Heiden Laboratory, and a voltage of about 2 kV was applied to generate plasma.

Next, the coating liquid was removed by cleaning the lyophilic substrate surface using a dry ice cleaning machine manufactured by Air Water. As a result, a substrate on which a pattern of lyophilic regions and lyophobic regions was formed was obtained.

Next, using an inkjet head (MEMS head 1 pL) manufactured by Konica Minolta, X-41-1053 manufactured by Shin-Etsu Chemical Co., Ltd. was added to 30% on the substrate after the above-mentioned process on which the pattern of the lyophilic region and the liquid-repellent region was formed. 50% methyl isobutyl ketone and 20% propylene glycol were added to prepare an ink, which was applied to the lyophilic region. After drying at 120° C. for 30 minutes, it was irradiated with ultraviolet rays for 5 minutes and cured to form a bank. These bank walls were formed in a grid shape with a width of 10 μm.

(Formation of light-emitting layer)
The substrate on which the anode and bank were formed was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and UV ozone cleaned for 5 minutes. Next, in a nitrogen atmosphere, using an ink composition for forming a light-emitting layer having the following composition, a piezoelectric inkjet printer head manufactured by Konica Minolta, which is a piezoelectric inkjet printer head having the structure shown in FIG. KM1024i” was used to inject the ink composition onto the substrate at 40° C. under conditions such that the layer thickness after drying was 50 nm, and then dried at 120° C. for 30 minutes to form a light-emitting layer.

<Coating solution for forming light-emitting layer>
Host compound KH-22 22.8 parts by weight Luminous dopant RD-3 7.2 parts by weight Propylene glycol monomethyl ether acetate 2000 parts by weight

(Formation of electron injection layer and cathode)
Subsequently, the substrate was attached to the vacuum deposition apparatus. In addition, a molybdenum resistance heating boat containing sodium fluoride and potassium fluoride was attached to a vacuum deposition apparatus, and the vacuum chamber was evacuated to 4×10 ⁻⁵ Pa. After that, the boat was energized and heated, and sodium fluoride was vapor-deposited on the light-emitting layer and bank at 0.02 nm/sec to form a thin film with a thickness of 1 nm. Similarly, potassium fluoride was vapor-deposited on the sodium fluoride thin film at 0.02 nm/sec to form an electron injection layer with a layer thickness of 1.5 nm.

Subsequently, aluminum was evaporated to form a cathode with a thickness of 100 nm.

(sealing)
A sealing substrate was adhered to the laminate formed by the above steps using a commercially available roll laminator.

As a sealing substrate, a 1.5 μm-thick adhesive was applied to a flexible 30 μm-thick aluminum foil (manufactured by Toyo Aluminum Co., Ltd.) using a two-liquid reactive urethane-based adhesive for dry lamination. A layer was provided and a polyethylene terephthalate (PET) film having a thickness of 12 μm was laminated.

A thermosetting adhesive as a sealing adhesive was uniformly applied to a thickness of 20 μm along the bonding surface (glossy surface) of the aluminum foil of the sealing substrate using a dispenser. This was dried under a vacuum of 100 Pa or less for 12 hours. Furthermore, the sealing substrate is moved to a nitrogen atmosphere with a dew point temperature of −80° C. or less and an oxygen concentration of 0.8 ppm, and dried for 12 hours or more, and the moisture content of the sealing adhesive is adjusted to 100 ppm or less. did.

As the thermosetting adhesive, an epoxy-based adhesive obtained by mixing the following (A) to (C) was used.

(A) bisphenol A diglycidyl ether (DGEBA)
(B) Dicyandiamide (DICY)
(C) Epoxy Adduct Curing Accelerator The encapsulation substrate is adhered to and arranged on the laminate, and a pressure roller is used to press the pressure roller at a temperature of 100° C., a pressure of 0.5 MPa, and an apparatus speed of 0.3 m/min. It was tightly sealed under the crimping condition of .

As described above, the organic EL element 101a was produced.

<<Preparation of Organic EL Element 101b>>
Organic EL element 101b was produced in the same manner as in the production of organic EL element 101a, except that the atmosphere for film formation of the light-emitting layer was air (temperature: 20° C.; humidity: 50%).

<<Production of organic EL elements 102 to 131>>
Elements 102a to 131a were produced in the same manner as in the production of organic EL element 101, except that the polymer was changed to the conditions shown in Table I.

<Coating solution for forming light-emitting layer>
Polymer listed in Table I 15 parts by weight Host compound KH-22 11.4 parts by weight Luminescent dopant RD-3 3.6 parts by weight Propylene glycol monomethyl ether acetate 2000 parts by weight

In addition, elements 102b to 131b were produced in the same manner, except that the atmosphere for film formation of the light-emitting layer was air (temperature: 20° C.; humidity: 50%) and the polymer was changed to the conditions shown in Table I.

≪Evaluation method≫
The organic EL elements 101a to 131a and 101b to 131b produced were evaluated as follows.

(1) Measurement of Conductivity of Polymer From the coating solution for forming the light-emitting layer, the host compound and the light-emitting dopant were removed to prepare a polymer-only coating solution, and a separate film was formed on a quartz substrate in the same manner. The resistivity of the film-forming surface was measured using Hiresta UX manufactured by Nitto Seiko Analytic Tech, and the reciprocal of the resistivity was derived as the electrical conductivity.

(2) Evaluation of polymer ratio P In the produced organic EL elements 101a to 131a, the distribution state of the polymer, host compound, and luminescent dopant in the light-emitting layer was analyzed by the time-of-flight secondary ion mass spectrometry (TOF-SIMS) described above. ) under the following conditions. Similar values were obtained for the elements 101b to 131b.

(Measurement condition)
Primary ion: Double charged ion of bismuth cluster (Bi ³⁺⁺ )
Primary ion acceleration voltage: 30 kV
Mass range (m/z): 0-1500
Measurement range: 100 μm×100 μm
Number of scans: 16 scans/cycle
Number of pixels (one side): 256 pixels
Etching ion: Ar gas cluster ion beam (Ar-GCIB)
Etching ion acceleration voltage: 5.0 kV

The polymer ratio P is represented by the following formula (i).
(i) _P =IP/( _{IP +} IH+ _IDp )
In the formula, I _P , I _H and I _Dp are the secondary ion intensities of the polymer, charge-transporting host compound and luminescent dopant measured by time-of-flight secondary ion mass spectrometry (TOF-SIMS).

Moreover, the polymer ratios Pa, Pb and Pc are expressed as follows depending on the position in the thickness direction in the light-emitting layer.
Pa: polymer ratio in the vicinity of the anode-side interface (x = (D-[D/10])) Pb: polymer ratio in the central portion (x = D/2) Pc: in the vicinity of the cathode-side interface (x = D/10) Polymer ratio Here, x indicates the position in the thickness direction in the light-emitting layer. 0, the anode side interface is represented by x=D.

The Pa/Pb and Pc/Pb values are given in Table I.

(3) Evaluation of external quantum yield (EQE ratio) For evaluation of the emission external quantum yield of the organic EL elements 101a to 131a and 101b to 131b, a constant current of 2.5 mA/cm ² was applied at room temperature (25°C). When lighting is performed under density conditions, the emission external quantum yield of each element is measured using a spectral radiance meter CS-2000 (manufactured by Konica Minolta), and the emission external quantum yield of the element 101a is set to 100. The relative value of

(4) Evaluation of driving life (LT ratio) For evaluating the driving life of the organic EL elements 101a to 131a and 101b to 131b, lighting was performed at room temperature (25 ° C.) under 100 cd / m ² conditions, and spectral radiance was measured. Using CS-2000 (manufactured by Konica Minolta Co., Ltd.), the luminance of each element was measured, and the relative value was obtained when the lifetime from the start of lighting of the element 101a to half luminance was defined as 100.

(5) Performance evaluation at the time of production in the atmosphere The (3) relative value of the emission external quantum yield and the (4) relative value of the drive lifetime of the organic EL elements 101b to 131b produced in the atmosphere were measured under a nitrogen atmosphere. was divided by the values of the organic EL elements 101a to 131a manufactured in 1. to obtain the performance ratio (%).

These results are shown in Table I.

（注）ポリマー導電率［Ｓ／ｍ］の不等号（＜）については、実際には、表に記載の数値を下回ることを示す。

(Note) Regarding the inequality sign (<) of the polymer conductivity [S/m], it actually indicates that it is lower than the numerical value described in the table.

From Table I, it can be seen that the organic EL elements 106 to 131, which are examples of the present invention, can achieve both luminous efficiency and drive life, and suppression of performance deterioration during manufacturing in the atmosphere, as compared to the organic EL elements 101 to 105, which are comparative examples. I understand.

[Example 2]
<<Production of Organic EL Element 201>>
An organic EL element 201a was produced in the same manner as in the production of the organic EL element 101a, except that the following light-emitting layer forming coating liquid was used.

<Coating solution for forming light-emitting layer>
Host compound KH-1 76 parts by mass Luminescent dopant BD-2 24 parts by mass Propylene glycol monomethyl ether acetate 2000 parts by mass

<<Preparation of organic EL element 201b>>
An organic EL element 201b was produced in the same manner as in the production of the organic EL element 201a, except that air (temperature 20° C.; humidity 50%) was used as the atmosphere for film formation of the light-emitting layer.

<<Production of organic EL elements 202 to 214>>
Elements 202a to 214a were produced in the same manner as in the production of the organic EL element 201a, except that the polymer was changed to the conditions shown in Table II.

<Coating solution for forming light-emitting layer>
Polymer compound listed in the table 15 parts by mass Host compound KH-1 11.4 parts by mass Luminescent dopant BD-2 3.6 parts by mass Propylene glycol monomethyl ether acetate 2000 parts by mass

Elements 202b to 214b were produced in the same manner, except that the atmosphere for film formation of the light-emitting layer was air (temperature: 20° C.; humidity: 50%), and the polymer was changed to the conditions shown in Table II.

Then, the same evaluation as in Example 1 was performed. These results are shown in Table II.

From Tables I and II, it can be seen that the organic EL device of the present invention can obtain the same effect regardless of whether a red light-emitting dopant or a blue light-emitting dopant is used as the light-emitting dopant.

[Example 3]
<<Production of organic EL elements 301 and 302>>
In the preparation of the organic EL element 130a, the coating solution for forming the light-emitting layer was changed to the following, and atactic polystyrene (weight average molecular weight: 280,000, manufactured by Sigma-Aldrich) and syndiotactic polystyrene (weight average molecular weight: 310,000; Macromolecule, 1988) , 21, 3356) were changed to the conditions shown in Table III, and organic EL devices 301a and 302a were produced in the same manner. Organic EL elements 301b and 302b manufactured in the atmosphere were produced in the same manner, except that the atmosphere for film formation of the light-emitting layer was air (temperature: 20° C.; humidity: 50%).

<Coating solution for forming light-emitting layer>
Polymer 15 parts by mass Host compound KH-2 11.4 parts by mass Luminescent dopant BD-3 3.6 parts by mass Propylene glycol monomethyl ether acetate 2000 parts by mass

Then, the same evaluation as in Example 1 was performed. These results are shown in Table III.

From Table III, it can be seen that the organic EL device of the present invention has even better luminous efficiency and drive life, and suppresses deterioration of performance during production in the atmosphere, because the polymer is a mixture of components with different stereoregularities. It turns out that they can be compatible.

[Example 4]
<<Production of Organic EL Element 401>>
An organic EL element 401a was produced in the same manner as in the production of the organic EL element 101a, except that the coating solution for forming the light-emitting layer was changed to the following. An organic EL element 401b was produced in the same manner as in the production of the organic EL element 401a, except that air (temperature 20° C.; humidity 50%) was used as the atmosphere for film formation of the light-emitting layer.

<Coating solution for forming light-emitting layer>
Host compound KH-12 76 parts by mass Luminescent dopant BD-5 24 parts by mass Propylene glycol monomethyl ether acetate 2000 parts by mass

<<Production of organic EL elements 402 to 410>>
Elements 402a to 410a were produced in the same manner as in the production of organic EL element 401a, except that the polymer was changed to the conditions shown in Table IV. Elements 402b to 410b were produced in the same manner, except that the atmosphere for film formation of the light-emitting layer was air (temperature: 20° C.; humidity: 50%).

<Coating solution for forming light-emitting layer>
Polymer compound listed in the table 15 parts by weight Host compound KH-12 11.4 parts by weight Luminous dopant BD-5 3.6 parts by weight Propylene glycol monomethyl ether acetate 2000 parts by weight

Then, the same evaluation as in Example 1 was performed. These results are shown in Table IV.

From Table IV, the organic EL device of the present invention has a polymer mass ratio of 5 to 80% by mass when the total mass of the polymer, host compound and luminescent dopant is 100, so that the luminous efficiency It can be seen that the driving life is further excellent, and that deterioration in performance during production in the atmosphere can be suppressed.

[Example 5]
<<Production of organic EL elements 501 to 507>>
An organic EL element 501a was produced in the same manner as in the production of the organic EL element 130a, except that the coating solution for forming the light-emitting layer was changed to the following. Next, two types of polymers, polystyrene (weight average molecular weight 280,000, manufactured by Sigma-Aldrich) and poly(4-vinylphenol) (weight average molecular weight 250,000, manufactured by Sigma-Aldrich), were added to the content ratio shown in Table V. Organic EL elements 502a to 507a were produced in the same manner, except that addition was changed in . Organic EL elements 501b to 507b manufactured in the air were produced in the same manner, except that the atmosphere for film formation of the light-emitting layer was air (temperature: 20° C.; humidity: 50%).

<Coating solution for forming light-emitting layer>
Polymer 15 parts by mass Host compound KH-15 11.4 parts by mass Luminescent dopant BD-4 3.6 parts by mass Propylene glycol monomethyl ether acetate 2000 parts by mass

Then, the same evaluation as in Example 1 was performed. These results are shown in Table V.

From Table V, it can be seen that the polymer ratio can be controlled by adjusting the content ratio using various polymers, and when the polymer ratio P is Pa≦Pc, especially when Pa<Pc, the luminous efficiency and driving life are further improved. It can be seen that it is excellent and can further suppress the deterioration of performance during production in the atmosphere.

From the above results, it can be seen that the problems of the present invention can be solved by controlling the behavior of holes and electrons, particularly by controlling the ratio of the polymer contained in the light-emitting layer.
That is, an organic electroluminescence element that has high luminous efficiency, has a long life, can suppress performance deterioration during manufacturing in the atmosphere, and can be manufactured at low cost, a method for manufacturing the same, a lighting device, and a display An apparatus and printed model can be provided.

1 substrate 2 bank (insulating layer)
2a concave portion 2b convex portion 10 organic electroluminescence element 11 substrate 12 anode 13 hole injection layer 14 hole transport layer 15 light emitting layer 16 electron transport layer 17 electron injection layer 18 cathode 21 blue light emitting pixel 22 green light emitting pixel 23 red light emitting pixel 30 Sealing layer 40 image display unit 41 light emitting image display unit 42 non-light emitting image display unit 100 line head type head unit 101 transport mechanism 102, 103, 104 head N nozzle H head HU head unit

Claims (20)

An organic electroluminescence element having an image display portion sandwiched between an anode and a cathode facing each other on at least a substrate,
wherein the image display section is composed of a luminescent image display section and a non-luminescent image display section,
the light-emitting image display section has at least a light-emitting layer adjacent to an electrode, a charge injection layer, or a charge transport layer;
the light-emitting layer contains a polymer having a conductivity of 1 S/m or less, a charge-transporting host compound, and a light-emitting dopant;
An organic electroluminescence device, wherein in the light-emitting layer, a polymer ratio P represented by the following formula (i) satisfies the following condition (ii).
(i) _P =IP/( _{IP +} IH+ _IDp )
(ii) At least either Pa/Pb or Pc/Pb is 0.8 or more and less than 2.2.
[Wherein, I _P , I _H and I _Dp are a polymer, a charge-transporting host compound, and a luminous is the secondary ion intensity of the dopant.
Pa is the polymer ratio near the interface on the anode side (x = (D-[D/10])),
Pb is the polymer ratio in the central part (x=D/2),
Pc is the polymer ratio near the cathode-side interface (x=D/10).
However, x indicates the position in the thickness direction in the light-emitting layer. The anode-side interface is represented by x=D. ] 2. The organic electroluminescence device according to claim 1, wherein the polymer ratio P satisfies the following condition (iii).
(iii) At least either Pa/Pb or Pc/Pb is 0.95 or more and less than 2.0 3. The organic electroluminescence device according to claim 1, wherein the polymer ratio P satisfies the following condition (iv).
(iv) at least one of Pa/Pb or Pc/Pb is 1.1 or more and less than 1.8 The organic electroluminescence device according to any one of claims 1 to 3, wherein the polymer ratio P satisfies the condition (v).
(v) Pa≦Pc The organic electroluminescence device according to any one of claims 1 to 4, wherein the polymer ratio P satisfies condition (vi).
(vi) Pa<Pc 6. Any one of claims 1 to 5, wherein the weight ratio of the polymer in the light-emitting layer is in the range of 5 to 80% by weight when the total weight of the light-emitting layer is 100. The organic electroluminescence device according to Item 1. 7. The organic electroluminescence device according to any one of claims 1 to 6, wherein the polymer has a conductivity of 1E-8 S/m or less. The organic electroluminescence device according to any one of claims 1 to 7, wherein the polymer is a polymer containing benzene rings. The organic electroluminescence device according to any one of claims 1 to 8, wherein the polymer is a polymer containing benzene rings as side chains. The organic electroluminescence device according to any one of claims 1 to 9, wherein the polymer is polystyrene. The organic electroluminescence device according to any one of claims 1 to 9, wherein the polymer is a polystyrene derivative. 12. The organic electroluminescence device according to claim 11, wherein the polystyrene derivative is polyvinylphenol. 13. The organic electroluminescence device according to any one of claims 1 to 12, wherein the polymer is a mixture of components with different stereoregularities. 14. The organic electroluminescence device according to any one of claims 1 to 13, wherein the light-emitting layer directly adjoins at least an electrode or a charge injection layer. 15. The organic electroluminescence device according to any one of claims 1 to 14, wherein the light-emitting layer is directly adjacent to an electrode. A method for manufacturing an organic electroluminescence device for manufacturing the organic electroluminescence device according to any one of claims 1 to 15,
A method for producing an organic electroluminescence device, comprising: forming the light-emitting layer by an inkjet printing method. 17. The method of manufacturing an organic electroluminescence element according to claim 16, further comprising forming the light-emitting layer by an inkjet printing method in the atmosphere. A lighting device comprising the organic electroluminescence device according to any one of claims 1 to 15. A display device comprising the organic electroluminescence device according to any one of claims 1 to 15. A printed model comprising the organic electroluminescence element according to any one of claims 1 to 15.

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