Organic electroluminescent element, method for controlling emission wavelength of organic electroluminescent element, program for implementing said method, and computer-readable recording medium with said program recorded thereon

Abstract

This organic electroluminescent element comprising a hole injection part, an electron injection part, and an organic part arranged between the hole injection part and the electron injection part, the organic part including a light-emitting layer, is configured such that the organic part has a refractive index periodic structure formed so that the refractive index periodically changes in a predetermined direction in a cross-sectional view obtained by cutting the organic part in a direction orthogonal to the thickness direction, or an electric field intensity periodic structure or a current intensity periodic structure, and light from the light-emitting layer causes resonance in the periodic structure. Through this configuration, the number of parameters to be considered in simulation and quality inspection during element design is reduced, which enables simulation and quality inspection to be more accurate, easier, and efficient.

Description

Organic electroluminescent element, method for controlling the emission wavelength of an organic electroluminescent element, program for carrying out the method, and computer-readable recording medium on which the program is recorded

[0001] The present invention relates to an organic electroluminescent element that emits light after resonating light from an emitting layer, a method for controlling the emission wavelength of an organic electroluminescent element, a program for carrying out the method, and a computer-readable recording medium on which the program is recorded.

[0002] Organic electroluminescence elements (organic EL elements) are being used, for example, as organic solid-state semiconductor lasers. Organic solid-state semiconductor lasers have a wider wavelength tunability than inorganic semiconductor lasers, are easy to provide flexibility, and can be manufactured at low cost. Therefore, they are expected to be applied to various fields, such as laser light sources that oscillate at a specific wavelength, and display devices having a plurality of pixels with different emission wavelengths, and research and development is being actively carried out toward practical use. For example, Patent Document 1 describes a method for fabricating an organic EL element by forming a SiO ２ An optical resonator structure consisting of a diffraction grating is provided, and an organic layer (light amplification layer) containing BSBCz (4-4'-bis[(N-carbazole)styryl]biphenyl) and MoO ３ It has been confirmed that an organic solid-state semiconductor laser fabricated by forming an anode 10 having a laminated structure of a layer / Ag layer / Al layer in this order exhibits laser oscillation.

[0003] JP 2024-95739 A

[0004] As described above, Patent Document 1 discloses SiO ２ An organic solid-state semiconductor laser is described in which an optical resonator made of a diffraction grating is provided separately from the organic layer. However, in the organic solid-state semiconductor laser in which the optical resonator is provided as a separate member, in addition to performing simulations using the parameters of the organic layer during device design, the optical resonator is also formed of SiO ２ Simulations must be performed using the parameters of the diffraction grating, and the design must satisfy the Bragg equation.

[0005] As a result of intensive research to solve the above problems, the inventors have found that by providing an organic layer with a periodic refractive index structure and using this as an optical resonator, it is possible to eliminate the need for an optical resonator as a separate component. The present invention has been proposed based on this finding, and specifically has the following configuration.

[0006] [1] An organic electroluminescence element comprising: a hole injection section that injects holes; an electron injection section that injects electrons; and two or more organic sections disposed between the hole injection section and the electron injection section, wherein the two or more organic sections include a light-emitting layer that recombines holes and electrons to emit light, wherein the organic sections have a refractive index periodic structure formed so that a refractive index varies periodically in a predetermined direction in a cross section (cross section in the XY directions) cut in a direction perpendicular to a thickness direction (e.g., the Z direction), and light from the light-emitting layer resonates in the refractive index periodic structure. [2] The organic electroluminescence element according to [1], wherein the refractive index periodic structure has a periodic structure in which first regions and second regions are alternately arranged in the cross section, and the refractive index of the first region is different from the refractive index of the second region. [3] The organic electroluminescence element according to [2], wherein the refractive index periodic structure has a periodic structure in which, in the cross-sectional view, the first regions made of a first organic material and the second regions made of a second organic material are alternately arranged, and the refractive index of the first organic material is different from the refractive index of the second organic material. [4] The organic electroluminescence element according to [2], wherein the refractive index periodic structure has a periodic structure in which, in the cross-sectional view, the first regions in which the organic material is in a first excited state and the second regions in which the organic material is in a second state different from the first state are alternately arranged, and the refractive index in the first state is different from the refractive index in the second state. [5] The organic electroluminescence element according to any one of [2] to [4], wherein the period of the refractive index periodic structure is set to satisfy the following Bragg equation: mλ Ｂｒａｇｇ = 2n ｅｆｆ Λ ｍ [where m is the diffraction order, λ Ｂｒａｇｇ is the Bragg wavelength, n ｅｆｆis the effective refractive index of one of the first and second regions, Λ ｍand represent the pitch of the refractive index periodic structure.] [6] The organic electroluminescent element according to any one of [2] to [5], wherein the refractive index periodic structure has a periodic structure in which the linear first regions and the linear second regions are alternately arranged in a certain direction in the cross-sectional view. [7] The organic electroluminescent element according to [6], wherein the refractive index periodic structure has a periodic structure in which the linear first regions and the linear second regions are alternately arranged in the horizontal direction (X direction) in the cross-sectional view. [8] The organic electroluminescent element according to [6], wherein the refractive index periodic structure has a periodic structure in which the linear first regions and the linear second regions are alternately arranged in the direction (Y direction) perpendicular to the horizontal direction in the cross-sectional view. [9] The organic electroluminescent element according to any one of [2] to [5], wherein the refractive index periodic structure has a pattern in which the first regions are arranged in a honeycomb shape with the second regions as boundaries in the cross-sectional view.

[10] The organic electroluminescent element according to any one of [2] to [5], wherein the refractive index periodic structure has a pattern in which the circular band-shaped first regions and the circular band-shaped second regions are alternately arranged in a concentric circle in the cross-sectional view.

[11] The refractive index periodic structure includes at least two types of periodic structures selected from the group consisting of: a periodic structure in which the linear first regions and the linear second regions are alternately arranged in a certain direction in the cross-sectional view, a periodic structure having a pattern in which the first regions are arranged in a honeycomb shape with the second regions as boundaries in the cross-sectional view, and a periodic structure having a pattern in which the circular band-shaped first regions and the circular band-shaped second regions are alternately arranged in a concentric circle in the cross-sectional view.

[12] The organic electroluminescent element according to any one of [1] to

[11] , wherein the organic portion has at least two layers having a periodic concavo-convex shape.

[13] The organic electroluminescence element according to any one of [1] to

[12] , which has a structure having a periodic uneven shape, and the organic part is laminated on a surface of the structure having the uneven shape.

[14] The organic electroluminescent device according to any one of [1] to

[12] , wherein the organic part has an organic layer formed on a flat surface.

[15] The organic electroluminescent device according to any one of [1] to

[14] , wherein the organic part has at least one organic layer, and all of the organic layers constituting the organic part contain an organic semiconductor material.

[16] The organic electroluminescent device according to any one of [1] to

[15] , wherein the organic part contains at least an electrode.

[17] The organic electroluminescent device according to any one of [1] to

[16] , wherein the light-emitting layer contains a laser oscillation material.

[18] The organic electroluminescent device according to any one of [1] to

[17] , wherein the organic part has a first organic layer and a second organic layer adjacent to the first organic layer and having a refractive index different from that of the first organic layer.

[19] The organic electroluminescence element according to any one of [1] to

[18] , wherein the organic moiety has an adjacent layer adjacent to the light-emitting layer on at least one of the hole injection part side and the electron injection part side of the light-emitting layer, the adjacent layer having a refractive index different from that of the light-emitting layer.

[20] The organic electroluminescence element according to any one of [1] to

[19] , wherein the organic electroluminescence element is an organic solid-state semiconductor laser.

[21] A method for controlling the emission wavelength of an organic electroluminescence element, comprising: a hole injection section that injects holes; an electron injection section that injects electrons; and an organic section disposed between the hole injection section and the electron injection section, wherein the organic section includes a light-emitting layer that recombines holes and electrons to emit light, and wherein the organic section has a refractive index periodic structure in which the refractive index changes periodically in a predetermined direction in a cross section (cross section in the XY directions) perpendicular to a thickness direction (e.g., the Z direction) of the organic section, wherein the method controls the emission wavelength of the organic electroluminescence element by setting the period of the refractive index periodic structure.

[22] The refractive index periodic structure has a periodic structure in which first regions and second regions having a refractive index different from that of the first regions are alternately arranged in a predetermined direction in the cross section, wherein a calculation means calculates λ based on the following Bragg equation: Ｂｒａｇｇ and Λ ｍ A step of determining the relationship between mλ and mλ.Ｂｒａｇｇ = 2n ｅｆｆ Λ ｍ [where m is the diffraction order, λ Ｂｒａｇｇ is the Bragg wavelength, n ｅｆｆ is the effective refractive index of one of the first and second regions, Λ ｍ and represent the pitch of the refractive index periodic structure.] The pitch determining means determines the λ calculated by the calculation means. Ｂｒａｇｇ and Λ ｍ In the relationship, λ Ｂｒａｇｇ is the desired emission wavelength, and this λ Ｂｒａｇｇ Λ corresponding to ｍ Select the selected Λ ｍas the pitch of the refractive index periodic structure.

[23] A program causing a computer to function as the calculation means and the pitch determination means to implement the method according to

[22] .

[24] A computer-readable recording medium having the program according to

[23] recorded thereon.

[25] A method for controlling the light extraction characteristics of an organic electroluminescence device comprising: a hole injection section for injecting holes; an electron injection section for injecting electrons; and an emissive layer in which holes and electrons are recombined to emit light, wherein light generated in the emissive layer propagates laterally through the emissive layer and is extracted from a light extraction surface, the method comprising providing a recombination concentration section along the lateral direction of the emissive layer.

[26] An organic electroluminescence device with controlled light extraction characteristics manufactured by implementing the method according to

[25] .

[27] An organic electroluminescence element comprising: a hole injection section that injects holes; an electron injection section that injects electrons; a light-emitting layer disposed between the hole injection section and the electron injection section and that recombines holes and electrons to emit light; and an optical resonator that propagates the emitted light within the light-emitting layer, wherein light is extracted from a light extraction surface, the organic electroluminescence element comprising: a hole blocking layer on the electron injection section side of the light-emitting layer so as to be adjacent to the light-emitting layer; or an electron blocking layer on the hole injection section side of the light-emitting layer so as to be adjacent to the light-emitting layer; and a control member that controls light extraction characteristics.

[28] A display device having a plurality of pixels, wherein the plurality of pixels include the organic electroluminescence element according to claim 27.

[29] An organic electroluminescence device comprising: a hole injection section that injects holes; an electron injection section that injects electrons; and an organic section disposed between the hole injection section and the electron injection section, wherein the organic section includes a light-emitting layer that recombines holes and electrons to emit light, wherein when a voltage is applied between the hole injection section and the electron injection section, at least one of an electric field intensity periodic structure in which the electric field intensity varies periodically in a predetermined direction and a current intensity periodic structure in which the current intensity varies periodically in a predetermined direction is formed between the hole injection section and the electron injection section in a cross section taken along a direction perpendicular to the thickness direction of the organic section, and light from the light-emitting layer resonates with the electric field intensity periodic structure or the current intensity periodic structure.

[30] The organic electroluminescence device according to

[29] , wherein at least one of the hole injection section and the electron injection section includes an electrode layer having a conductive periodic structure whose conductivity varies periodically in a predetermined direction, and the electric field intensity periodic structure is formed with a period corresponding to the period of the conductive periodic structure.

[31] The organic electroluminescence element according to

[30] , wherein the current intensity periodic structure is formed with a period corresponding to the period of the conductive periodic structure.

[32] The organic electroluminescence element according to

[29] , wherein the organic part includes an organic layer having a conductive periodic structure whose conductivity varies periodically in a predetermined direction, and the current intensity periodic structure is formed with a period corresponding to the period of the conductive periodic structure.

[0007] In the organic electroluminescent element of the present invention, the refractive index periodic structure of the organic part functions as an optical resonator, so there is no need to provide an optical resonator separately from the organic part. Furthermore, in the organic electroluminescent element of the present invention, the electric field intensity periodic structure or current density periodic structure formed when a voltage is applied between the hole injection part and the electron injection part functions as an optical resonator, so there is no need to provide an optical resonator separately from the organic part. Therefore, according to the present invention, the number of parameters to be considered during simulations and quality inspections during element design is reduced, allowing these tasks to be performed accurately, easily, and efficiently.

[0008] 1 shows an example of an organic electroluminescent element of the present invention, where (a) is an exploded perspective view of the organic electroluminescent element, (b) is a cross-sectional view of the organic electroluminescent element shown in (a) in the XZ direction, and (c) is a cross-sectional view of the organic electroluminescent element taken along line A-A in (b) in the XY direction. An example of a refractive index periodic structure possessed by an organic portion of the organic electroluminescent element of the present invention is shown, where (a) is a cross-sectional view showing a periodic structure in which first regions and second regions are alternately arranged in the X direction, and (b) is a cross-sectional view showing a periodic structure in which the first regions and second regions are alternately arranged in the Y direction. An example of a refractive index periodic structure possessed by an organic portion of the organic electroluminescent element of the present invention is shown, where (a) is a cross-sectional view showing a periodic structure in which the first regions are arranged in a honeycomb pattern with the second regions as boundaries. An example of a refractive index periodic structure possessed by an organic portion of the organic electroluminescent element of the present invention is shown, where (b) is a cross-sectional view showing a periodic structure in which the first regions and second regions are alternately arranged in a concentric pattern. 1 shows the emission spectra of a red light-emitting device (R-OSLD), a green light-emitting device (G-OSLD), and a blue light-emitting device (B-OSLD) to which the present invention is applied.

[0023] FIG. 1 shows a comparison of the characteristics of a red light-emitting device (R-OSLD) to which the present invention is applied and a red light-emitting device (R-OLED) without a periodic refractive index structure, where (a) is the emission spectrum and (b) is a graph showing the angular dependence of emission intensity.

[0024] FIG. 1 shows a comparison of the characteristics of a green light-emitting device (G-OSLD) to which the present invention is applied and a green light-emitting device (G-OLED) without a periodic refractive index structure, where (a) is the emission spectrum and (b) is a graph showing the angular dependence of emission intensity.

[0025] FIG. 1 shows a comparison of the characteristics of a blue light-emitting device (B-OSLD) to which the present invention is applied and a blue light-emitting device (B-OLED) without a periodic refractive index structure, where (a) is the emission spectrum and (b) is a graph showing the angular dependence of emission intensity.

[0026] FIG. 1 shows a graph showing the driving voltage dependence of emission intensity of a red light-emitting device (R-OSLD) to which the present invention is applied. 1 is a graph showing the external quantum efficiency (EQE)-current density characteristics of a red light-emitting device (R-OSLD) to which the present invention is applied and a red light-emitting device (R-OLED) having no periodic refractive index structure, and a graph showing the driving voltage dependence of the emission intensity of a green light-emitting device (G-OSLD) to which the present invention is applied.1 is a graph showing the external quantum efficiency (EQE)-current density characteristics of a green light-emitting device (G-OSLD) to which the present invention is applied and a green light-emitting device (G-OLED) not having a periodic refractive index structure. 2 is a graph showing the drive voltage dependence of the luminous intensity of a blue light-emitting device (B-OSLD) to which the present invention is applied. 3 is a graph showing the external quantum efficiency (EQE)-current density characteristics of a blue light-emitting device (B-OSLD) to which the present invention is applied and a blue light-emitting device (B-OLED) not having a periodic refractive index structure. 4 is a graph showing the current density-voltage characteristics of a red light-emitting device (R-OSLD), a green light-emitting device (G-OSLD), and a blue light-emitting device (B-OSLD) to which the present invention is applied. 5 is a graph showing the luminance-voltage characteristics of a red light-emitting device (R-OSLD), a green light-emitting device (G-OSLD), and a blue light-emitting device (B-OSLD) to which the present invention is applied. 6 shows an example of an organic electroluminescence device of the present invention, where (a) is a cross-sectional view of the organic electroluminescence device in the XZ direction, and (b) is a cross-sectional view of the organic electroluminescence device in the XY direction taken along line B-B shown in (a). 1 shows an example of an organic electroluminescence element of the present invention, where (a) is a cross-sectional view of the organic electroluminescence element in the XZ direction, (b) is a plan view showing the electric field intensity periodic structure in a cross section (in the XY cross section) of the organic electroluminescence element taken along the CC line shown in (a), and (c) is a plan view showing the current intensity periodic structure in a cross section (in the XY cross section) of the organic electroluminescence element taken at a position corresponding to the CC line shown in (a). 1 is a cross-sectional view in the XZ direction showing an example of an electrode layer having a conductive periodic structure used in the organic electroluminescence element of the present invention. 1 is a cross-sectional view in the XZ direction showing an example of an organic layer having a conductive periodic structure used in the organic electroluminescence element of the present invention. 1 is a schematic diagram showing an example of a light-receiving sensor using the organic electroluminescence element of the present invention as a light-emitting section and a light-receiving section. 1 is a perspective view showing a circular diffraction grating used as a control member in the present technology. 1A and 1B show the results of simulation of the optical resonance mode of an element using a circular diffraction grating as a control member, where FIG. 1A shows the results of simulation of the optical resonance mode on the top surface, and FIG. 1B shows the results of simulation of the optical resonance mode on the longitudinal cross section.27 is a schematic perspective view showing a display device in which pixels are formed with edge-emitting organic solid-state semiconductor lasers that use a stripe-shaped diffraction grating as a control member. 28 is a schematic view showing the propagation direction of light in the organic solid-state semiconductor laser shown in FIG. 24 and the traveling direction of extracted light. 29 is a schematic view showing control of the polarization state of light generated in the light-emitting layer in the organic solid-state semiconductor laser shown in FIG. 24. 29 is a schematic perspective view showing a display device in which pixels are formed with top-emission organic solid-state semiconductor lasers that use a stripe-shaped diffraction grating as a control member. 30 is a schematic view showing the propagation direction of light in the organic solid-state semiconductor laser shown in FIG. 30 and the traveling direction of extracted light. 31 is a schematic cross-sectional view showing a display device in which pixels are formed with top-emission organic solid-state semiconductor lasers that use a partition wall as a control member. 32 shows a structural example of a first embodiment of an organic solid-state semiconductor laser according to the present technology, where (a) is a schematic cross-sectional view showing a state before current injection, and (b) is a schematic cross-sectional view showing the behavior of holes and electrons during current injection. 33 is a schematic cross-sectional view showing a structural example of a second embodiment of an organic solid-state semiconductor laser according to the present technology. 34 is a schematic cross-sectional view showing an example of an optical resonator structure. 35 is an energy level diagram of the organic solid-state semiconductor laser (laser element 1) fabricated in Example 1. 1 is a graph showing calculation results of exciton density distributions of the organic solid-state semiconductor lasers (laser elements 2 and 3, and comparative laser element 1) fabricated in Examples 2 and 3 and Comparative Example 1. FIG. 2 is a schematic cross-sectional view showing an example of a conventional organic solid-state semiconductor laser. Detailed Description of the Invention

[0009] The present invention will be described in detail below. The following description of the constituent elements may be based on representative embodiments or specific examples of the present invention, but the present invention is not limited to such embodiments or specific examples. In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits. Furthermore, the isotope of the hydrogen atoms present in the molecules of the compounds used in the present invention is not particularly limited. For example, all hydrogen atoms in the molecules may be 1H, or some or all may be 2H (deuterium D). "Transparent" in the present invention refers to a visible light transmittance of 50% or more, for example, 80% or more, for example, 90% or more, or for example, 99% or more. Visible light transmittance can be measured using an ultraviolet-visible spectrophotometer. The "refractive index" in the present invention can be a value measured by, for example, spectroscopic ellipsometry, prism coupling, spectral reflectance, microspectroscopy, or the like. The "electric field strength" in the present invention can be a value measured by a general measuring device, etc. The "current strength" in the present invention can be a value measured by a general measuring device, etc.

[0010] In the following description, in the organic electroluminescence element of the present technology, a configuration in which the organic portion has a refractive index periodic structure is referred to as “Embodiment I,” and a configuration in which at least one of an electric field intensity periodic structure and a current density periodic structure is formed when a voltage is applied between the hole injection portion and the electron injection portion is referred to as “Embodiment II.” Each configuration of Embodiment I and Embodiment II of the present technology will be described below.

[0011] <First Embodiment of Organic Electroluminescent Element> The organic electroluminescent element of this embodiment includes a hole injection section that injects holes, an electron injection section that injects electrons, and an organic section disposed between the hole injection section and the electron injection section, wherein the organic section includes a light-emitting layer that recombines holes and electrons to emit light, and the organic section has a periodic refractive index structure formed so that the refractive index varies periodically in a predetermined direction in a cross-sectional view (cross-sectional view in the XY direction) perpendicular to the thickness direction (e.g., the Z direction), and light from the light-emitting layer resonates in the periodic refractive index structure. The "cross-section" in the "cross-sectional view" referred to here may be, for example, a cross-section at a position (position in the Z direction) at which the periodic refractive index variation in the predetermined direction can be observed. In the organic electroluminescent element of this embodiment, the periodic refractive index structure of the organic section functions as an optical resonator, eliminating the need for an optical resonator separate from the organic section. This reduces the number of parameters to be considered during simulations and quality inspections during element design, making it possible to perform these tasks accurately, easily, and efficiently.

[0012] In one aspect of this embodiment, the refractive index periodic structure of the organic electroluminescence element has a periodic structure in which first regions and second regions are alternately arranged in a cross section of the organic part in the XY direction (hereinafter referred to as the "XY cross section"), and the refractive index of the first region can be different from the refractive index of the second region. The refractive index periodic structure can be such that, when the organic part is cut in the XY direction, a periodic structure in which the first regions and the second regions are alternately arranged appears in the cut cross section. The periodic structures of the first regions and the second regions in the XY cross section of the organic part will be specifically described with reference to FIG. 1 . FIG. 1 shows an example of an organic electroluminescent element of the present invention, where (a) is a perspective view of the organic electroluminescent element, (b) is a cross-sectional view of the organic electroluminescent element shown in (a) cut in the XZ direction, and (c) is a cross-sectional view of the organic electroluminescent element cut along line A-A shown in (b). The cross-section shown in (c) corresponds to a cross-section of the organic portion in the XY direction (XY cross-section), i.e., a "cross-section" of the organic layer in this embodiment cut in a direction perpendicular to the thickness direction. In FIG. 1, 1 denotes a hole injection portion, 2 denotes a first organic layer, 3 denotes a light-emitting layer serving as a second organic layer, and 4 denotes an electron injection portion, with the first organic layer 2 and the second organic layer 3 having different refractive indices. Furthermore, here, a plurality of convex portions 5 are periodically arranged at intervals on the surface of the hole injection portion 1, and the first organic layer 2, the second organic layer 3, and the electron injection portion 4 are sequentially stacked thereon. Here, each of these layers 2, 3, and 4 is formed in a shape with undulations (gentle unevenness) so as to follow the shape of the convex body 5. When such an organic electroluminescent element is cut along line A-A across the first organic layer 2 and the second organic layer 3, as shown in FIG. 1( c), cross sections 2C of the first organic layer 2 and cross sections 3C of the second organic layer 3 appear alternately arranged on the cut surface. Here, the first organic layer 2 and the second organic layer 3 have different refractive indices, and therefore the cross sections 2C and 3C also have different refractive indices. Therefore, the cross section 2C of the first organic layer 2 corresponds to the first region, and the cross section 3C of the second organic layer 3 corresponds to the second region, and the periodic structure in which these cross sections 2C and 3C are alternately arranged corresponds to the periodic structures of the first region and the second region in the XY cross-sectional view of the organic portion.The organic electroluminescent element shown in FIG. 1 is merely an example, and the configuration of the organic electroluminescent element of the present invention should not be construed as being limited by this specific example. For example, in the organic electroluminescent element shown in FIG. 1 , the first and second regions are periodically arranged in only one direction. However, in the organic electroluminescent element of the present invention, the first and second regions may be periodically arranged in two or more directions (e.g., two to eight directions) in the XY cross section, or may be periodically arranged in all directions in the XY cross section. For example, a refractive index periodic structure in which the first and second regions are periodically arranged in six directions in the XY cross section can be obtained by controlling the shape and dimensions of the convex body 5 so that the first and second regions form a honeycomb shape as shown in FIG. 3 (described below). Furthermore, a refractive index periodic structure in which the first and second regions are periodically arranged in all directions in the XY cross section can be obtained by controlling the shape and dimensions of the convex body 5 so that the first and second regions form a concentric circle shape as shown in FIG. 4 (described below). In the organic electroluminescent element shown in FIG. 1 , the organic portion is composed of two layers, a first organic layer 2 and a second organic layer (light-emitting layer) 3, but the number and types of layers of the organic portion that can be employed in the present invention are not limited to this. For possible layer configurations of the organic portion, see the description in the "Layer configuration of organic electroluminescent element" below. Furthermore, in the organic electroluminescent element shown in FIG. 1 , the convex body 5 is disposed on the hole injection portion 1, but the organic electroluminescent element of the present invention may have the convex body 5 disposed on the electron injection portion, and two or more organic layers and an electron injection portion laminated thereon to follow the shape of the convex body 5.

[0013] The first region and the second region in the XY cross-sectional view of the organic part are regions with different refractive indices. The difference in refractive index between the first region and the second region (refractive index of the first region - refractive index of the second region) is, for example, 0.1 or more in absolute value, and may be 0.2 or more or 0.3 or more. The difference in refractive index between the first region and the second region (refractive index of the first region - refractive index of the second region) is, for example, 0.1 or less in absolute value, and may be 0.2 or less or 0.3 or less. The refractive indices of the first region and the second region are, for example, 1.7 to 2.2, and may be 1.5 to 2.3, or 1.3 to 2.4. In the first and second regions, the refractive index of the first region may be lower than the refractive index of the second region, or the refractive index of the second region may be lower than the refractive index of the first region. Light from the light-emitting layer typically propagates through the region with the higher refractive index and is reflected by the region with the lower refractive index, causing resonance. The light propagated through the periodic refractive index structure is then emitted to the outside of the device, causing the organic electroluminescent device to emit light.

[0014] Here, in order to resonate the light from the light emitting layer in the periodic refractive index structure, the pitch between the first and second regions (the period of the periodic refractive index structure) can be set so as to satisfy the following Bragg equation: mλ Ｂｒａｇｇ = 2n ｅｆｆ Λ ｍ In the formula, m is the diffraction order, λ Ｂｒａｇｇ is the Bragg wavelength, n ｅｆｆ is the effective refractive index of one of the first and second regions, Λ ｍ and n represent the pitch of the refractive index periodic structure. ｅｆｆ is the effective refractive index of the region having the higher refractive index out of the first and second regions. m is a positive integer, and may be selected from integers 1 to 3, for example, or may be 1. As shown in the above formula, the Bragg wavelength λ Ｂｒａｇｇ is the pitch Λ of the refractive index periodic structure ｍ Therefore, the value determined by the target emission wavelength (λ Ｂｒａｇｇ ) corresponding to the pitch (Λ ｍ) to form a periodic refractive index structure, an organic electroluminescence element that emits light at a desired emission wavelength can be obtained. The organic electroluminescence element of this embodiment can be obtained by changing the combination of materials for the first region and the second region and the pitch Λ of the periodic refractive index structure. ｍ By controlling the wavelength of the first and second regions, the organic electroluminescent element can emit light in the visible region (for example, 400 to 780 nm), the infrared region (for example, 780 nm to 2 μm), or the ultraviolet region (for example, 280 to 400 nm). ｍ By controlling the wavelength of the first region and the second region, it is possible to make the organic electroluminescent element emit light at a wavelength in the red region (for example, 620 to 780 nm), the green region (for example, 490 to 575 nm), or the blue region (for example, 400 to 490 nm). In one aspect of this embodiment, the organic electroluminescent element emits light at a wavelength in the red region, and the material of the first region and the material of the second region can contain, for example, DCM (4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran) as a dopant, and the pitch Λ of the refractive index periodic structure can be controlled. ｍ In one aspect of this embodiment, the organic electroluminescent element emits light in a wavelength range of green, and the material of the first region and the material of the second region can be, for example, a material containing a benzothiazole (BTD) skeleton, a fluorene skeleton, or the like, and the pitch Λ of the refractive index periodic structure can be, for example, ｍ In one aspect of this embodiment, the organic electroluminescent element emits light with a wavelength in the blue region, and the material of the first region and the material of the second region can be, for example, a material containing BSBCz, and the pitch Λ of the refractive index periodic structure can be ｍ can be, for example, 250 to 270 nm.

[0015] Furthermore, in an embodiment in which a periodic refractive index structure is obtained by forming at least two organic layers on a surface having a periodic uneven shape, the conditions of the periodic uneven shape can be controlled to produce light emission of a desired color. The conditions of the uneven shape to be controlled include the period (pitch) of the uneven shape, the width of the convex and concave portions, and the height of the convex portions. Here, the width of the convex and concave portions is the length in the arrangement direction of the convex and concave portions. The following are embodiments of organic electroluminescent elements that employ ranges of each condition. In one embodiment of this embodiment, the organic electroluminescent element emits light at a wavelength in the red region (e.g., 630 nm), and the period of the periodic uneven shape is, for example, 360 to 430 nm, the width of the convex portions is, for example, 70 to 30 nm, the width of the concave portions is, for example, 30 to 70 nm, and the height of the convex portions is, for example, 40 to 160 nm. In one aspect of this embodiment, the organic electroluminescent element emits light at a wavelength in the green region (e.g., 530 nm), and the period of the periodic uneven shape is, for example, 300 to 340 nm, the width of the convex portions is, for example, 70 to 30 nm, the width of the concave portions is, for example, 30 to 70 nm, and the height of the convex portions is, for example, 40 to 160 nm. In one aspect of this embodiment, the organic electroluminescent element emits light at a wavelength in the blue region (e.g., 460 nm), and the period of the periodic uneven shape is, for example, 250 to 270 nm, the width of the convex portions is, for example, 70 to 30 nm, the width of the concave portions is, for example, 30 to 70 nm, and the height of the convex portions is 40 to 160 nm. Furthermore, the widths of the concave portions and the convex portions can be appropriately set in a ratio falling within a range between, for example, "concave width:convex width=70:30" and "concave width:convex width=30:70".

[0016] As shown in FIG. 2, an example of the periodic structure pattern of the first and second regions in an XY cross-sectional view is a stripe pattern in which linear first regions 6C, 8C and linear second regions 7C, 9C are alternately arranged in a certain direction. In this case, the arrangement direction of the first regions 6C, 8C and the second regions 7C, 9C may be the horizontal direction (X direction) as shown in FIG. 2(a) or the direction perpendicular to the horizontal direction (Y direction) as shown in FIG. 2(b). As shown in FIG. 3, an example of the periodic structure pattern of the first and second regions in an XY cross-sectional view is a honeycomb pattern in which the first regions 11C are arranged with the second regions 12C as boundaries. The honeycomb-shaped periodic structure shown in FIG. 3 is a pattern in which the first regions 11C and the second regions 12C are arranged periodically in six directions in the XY cross-section. In this honeycomb-shaped periodic structure, the refractive index of the second region 12C can be lower than that of the first region 11C. An example of the periodic structure pattern of the first and second regions in the XY cross section is a pattern in which circular band-shaped first regions 13C and circular band-shaped second regions 14C are concentrically and alternately arranged, as shown in Figure 4. The concentric periodic structure shown in Figure 4 is a pattern in which the first regions 13C and the second regions 14C are periodically arranged in all directions in the XY cross section. In this embodiment, the refractive index periodic structure of the organic portion may have one of a striped periodic structure, a honeycomb periodic structure, and a concentric periodic structure in the XY cross section, or may have two or more periodic structures selected from the group consisting of a striped periodic structure, a honeycomb periodic structure, and a concentric periodic structure in the XY cross section.

[0017] The three-dimensional shape of the refractive index periodic structure is not particularly limited. In one aspect of this embodiment, as shown in the examples of FIGS. 1(a) and 1(b) above, the refractive index periodic structure has a laminated structure in which at least two organic layers having periodic concave-convex shapes are stacked, and the laminated structure can include a combination of adjacent organic layers (first organic layer 2, second organic layer 3) having different refractive indices. In such a refractive index periodic structure, as shown in FIG. 1(c), when the organic layer is cut along line A-A across the first organic layer 2 and the second organic layer 3, a periodic structure appears on the cut surface in which cross sections 2C corresponding to the first region and cross sections 3C corresponding to the second region are alternately arranged. Examples of organic layers having periodic concave-convex shapes include the corrugated organic layer shown in FIG. 1, as well as organic layers having periodically concave or convex surfaces and organic layers having a concentrically wavy shape. For example, when one of the first organic layer and the second organic layer has these periodic uneven shapes at the interface with the other organic layer, the other organic layer can have an inverted shape of the uneven shape of the one organic layer at the interface with the other organic layer.

[0018] A periodic refractive index structure having a laminated structure in which at least two organic layers having a periodic uneven shape are stacked can be obtained, for example, by sequentially depositing organic materials on a surface having a periodic uneven shape to form at least two organic layers. When an organic material is deposited on a surface having a periodic uneven shape, an organic layer is formed that conforms to the uneven shape. By depositing an additional organic material on top of the organic material, a laminated structure of organic layers having a gentle uneven shape (undulation) can be obtained. However, in this case, it is not necessary to form all of the organic layers contained in the organic electroluminescent element on the surface having an uneven shape; at least some of the organic layers may be formed on a flat surface. For example, some organic layers may be formed on a flat surface, forming an uneven shape on the surface of the organic layer, and the remaining organic layers may be formed on the surface having an uneven shape. Here, the term "flat surface" as used herein refers to the surface of a substrate on which an uneven shape is not intentionally formed, and does not mean a completely flat surface as long as it is a substantially flat surface. Examples of a surface having a periodic uneven shape on which an organic layer is formed include the surface of an organic layer on which a periodic uneven shape is formed by etching or the like, and the surface of a substrate with convex bodies on which a plurality of convex bodies are periodically formed at intervals, as shown in Figures 1(a) and 1(b). That is, in one aspect of this embodiment, the organic electroluminescent element includes a structure (a substrate on which an organic layer is formed) having a periodic uneven shape, and two or more organic layers are laminated on the surface of this structure having a periodic uneven shape. Here, the material of the convex bodies may be the constituent material of the organic layer or an insulating material. For examples of constituent materials of the organic layer, see the description in the "Layer Structure of Organic Electroluminescent Element" section below. Examples of insulating materials used for the convex bodies include glass, silicon dioxide, and plastic. The substrate may be an organic layer, a hole injection part, or an electron injection part. However, in the organic electroluminescent element of the present invention, what is set to satisfy the Bragg equation is not the periodic uneven shape on the surface on which a film is formed, but the period of the refractive index periodic structure in the XY cross section.

[0019] The first and second regions can be composed of organic materials having different refractive indices. That is, in one aspect of this embodiment, the refractive index periodic structure of the organic electroluminescent element has a periodic structure in which, in an XY cross-sectional view, first regions made of a first organic material and second regions made of a second organic material are alternately arranged, and the refractive index of the first organic material is different from the refractive index of the second organic material. The first organic material may be composed of only one type of organic material, or may contain two or more types of organic materials. The second organic material may be composed of only one type of organic material, or may contain two or more types of organic materials. Furthermore, the first and second organic materials may be organic materials having different refractive indices, and may be composed of different types of organic materials, may contain a common organic material, or may be composed of the same constituent materials with only a different composition ratio. For examples of materials that can be used for the first organic material and the second organic material, please refer to the description of the materials for the organic layers (e.g., hole injection layer, hole transport layer, electron blocking layer, light-emitting layer, hole blocking layer, electron transport layer, and electron injection layer) listed in the section "Layer Structure of Organic Electroluminescent Device" below. For example, by selecting a combination of materials with different refractive indices from the example materials, one of the combinations can be used as the first organic material and the other as the second organic material. For specific forms of the refractive index periodic structure when the first region is made of the first organic material and the second region is made of the second organic material, please refer to the description of the refractive index periodic structure having a periodic structure in which the first region and the second region are alternately arranged. For example, in an element having a laminated structure in which the refractive index periodic structure is formed by stacking at least two organic layers each having a periodic uneven shape, at least one layer (first organic layer) of the laminated structure is made of a first organic material, and a second organic layer adjacent to the first organic layer is made of a second organic material, thereby making it possible to create an organic electroluminescence element in which the periodic structures of the first region and the second region, which have different refractive indexes, appear in the XY cross section.Examples of combinations of the first organic layer and the second organic layer include a hole transport layer (refractive index: 1.888), a hole transport layer (refractive index: 1.896), an emitting layer (refractive index: 2.10) formed of BSBCz, an emitting layer (refractive index: 1.91), an electron transport layer (refractive index: 1.72), an electron transport layer (refractive index: 1.789), an electron transport layer (refractive index: 1.72), and an electron transport layer (refractive index: 1.91) (the refractive index values ​​in parentheses are the refractive indexes measured for 460 nm wavelength light). Specific examples include a combination of two layers selected from the above hole transport layers, a combination of two layers selected from the above emitting layers, and a combination of two layers selected from the above electron transport layers. Furthermore, the refractive indexes of the hole transport layer and the electron transport layer can be as low as possible (for example, at least 1.8 or less) relative to the refractive index of the emitting layer (for example, 1.9). Therefore, a combination of a hole transport layer and an emitting layer, or a combination of an electron transport layer and an emitting layer can also be used as a combination of the first organic layer and the second organic layer.

[0020] Examples of the First Embodiment As a specific example of an organic electroluminescence element of the aspect shown in Figure 1, periodically arranged convex structures were formed on the surface of a hole injection section (anode) formed on a substrate, and a hole injection layer, a hole transport layer, an emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, and an electron injection section (cathode) were formed thereon in this order to fabricate bottom-emission type red light-emitting element (R-OSLD), green light-emitting element (G-OSLD), and blue light-emitting element (B-OSLD), respectively. These elements were designed so that a refractive index periodic structure satisfying the Bragg equation was formed in the XY cross section taken along line A-A in Figure 1(b), for example. The Bragg wavelength λ used in the design ＢｒａｇｇThe thicknesses of the R-OSLD, G-OSLD, and B-OSLD were 630 nm, 530 nm, and 460 nm, respectively. The thicknesses of the individual layers were 30 nm for the anode, 10 nm for the hole injection layer, 45 nm for the light-emitting layer, 15 nm for the hole blocking layer, 1 nm for the electron injection layer, and 100 nm for the cathode. The thicknesses of the hole transport layer were 50 to 150 nm for the red light-emitting element, 50 to 100 nm for the green light-emitting element, and 50 to 90 nm for the blue light-emitting element. The thicknesses of the electron transport layer were 100 to 230 nm for the red light-emitting element, 100 to 160 nm for the green light-emitting element, and 100 to 140 nm for the blue light-emitting element. Specific examples of the materials and thicknesses of each layer include ITO (30 nm), HATCN (10 nm), NPD (70 nm), EML (45 nm), T2T (15 nm), ETM576 (120 nm), LiF (1 nm), Al (1 nm), and Ag (100 nm), with the EML consisting of BHKT01 and 5 wt % emitter. Examples of emitters include the red emitter DCM, the green emitter Z37, and the blue emitter BDKT01. For comparison, bottom-emission red (R-OLED), green (G-OLED), and blue (B-OLED) light-emitting devices were fabricated using the same procedure, except that the periodically arranged convex structures were not formed. The emission spectra of the R-OSLD, G-OSLD, and B-OSLD are shown in Fig. 5, the emission spectra (a) and the angle dependence of emission intensity (b) of the R-OSLD and R-OLED are shown in Fig. 6, the emission spectra (a) and the angle dependence of emission intensity (b) of the G-OSLD and G-OLED are shown in Fig. 7, and the emission spectra (a) and the angle dependence of emission intensity (b) of the B-OSLD and B-OLED are shown in Fig. 8. The drive voltage dependence of the emission intensity of the R-OSLD is shown in Fig. 9, the external quantum efficiency (EQE)-current density characteristics of the R-OSLD and R-OLED are shown in Fig. 10, the drive voltage dependence of the emission intensity of the G-OSLD is shown in Fig. 11, the external quantum efficiency (EQE)-current density characteristics of the G-OSLD and G-OLED are shown in Fig. 12, the drive voltage dependence of the emission intensity of the B-OSLD is shown in Fig. 13, and the external quantum efficiency (EQE)-current density characteristics of the B-OSLD and B-OLED are shown in Fig. 14. Furthermore, the current density-voltage characteristics of the R-OSLD, G-OSLD, and B-OSLD are shown in FIG. 15, and the luminance-voltage characteristics are shown in FIG.As shown in Figure 6, the R-OSLD, G-OSLD, and B-OSLD, which have a periodic refractive index structure formed at a specific period, have a significantly narrower emission spectrum width than the R-OLED, G-OLED, and B-OLED, which do not have a periodic refractive index structure, and also have a small angular dependency of the emission intensity and high directivity of light emission. This confirms that a configuration in which a periodic refractive index structure is formed at a specific period improves the color purity and directionality of the emission light.

[0021] Other Aspects of Embodiment I: The first and second regions can be composed of organic materials with different energy states. That is, in one aspect of this embodiment, the refractive index periodic structure of the organic electroluminescent element has a periodic structure in which, in an XY cross-sectional view, first regions in which the organic material is in an excited first state and second regions in which the organic material is in a second state different from the first state are alternately arranged, and the refractive index of the first state is different from the refractive index of the second state. The term "excitation" used here refers to carriers injected into the organic portion recombining on the organic molecules, thereby placing the organic molecules in a high energy state (excited state). The "excited first state" can also be referred to as an excited state. The first region here can be a region in which the organic material can be in an excited state. The "second state" can be an energy state of the organic material that is different from the first state. The "second state" can be either a ground state or an excited state, but the exciton density in the excited state is different from that in the first state. The second region can be a region that can assume a ground state or an excited state with a different exciton density from that of the first region when the first region is in an excited state. The energy states of the first and second regions can be determined, for example, from emission and absorption spectra. In organic materials, the refractive index changes between the ground state and the excited state, and even in excited states, the refractive index differs if the exciton density differs. Therefore, in this embodiment, the same organic material can be used for the first and second regions, and the first and second regions can be formed in the same organic layer. This simplifies the organic layer formation process. An example of an organic layer in which the first and second regions are formed is an emissive layer. In this case, the emissive layer functions both as an emissive layer and a resonator. Alternatively, an organic layer capable of current excitation may be provided in addition to the emissive layer, and the first and second regions may be formed on this layer. For a description of the emissive layer and examples of materials for the organic layer capable of current excitation, please refer to the description of the emissive layer in the "Layer Structure of Organic Electroluminescent Device" section below.One method for forming a first region and a second region having different energy states in an organic layer is to vary the amount of carriers injected into the first region and the second region. An example of a method for varying the amount of carriers injected into the first region and the second region will be described with reference to FIG. 17 . FIG. 17 shows an example of an organic electroluminescent element, with (a) being a cross-sectional view of the organic electroluminescent element in the XZ direction, and (b) being a cross-sectional view of the organic electroluminescent element taken along line B-B in (a) in the XY direction. In FIG. 17 , 15 denotes a hole injection portion, 16 denotes a first organic layer, 17 denotes a light-emitting layer serving as a second organic layer, and 18 denotes an electron injection portion. In this example, as shown in FIGS. 17(a) and 17(b), a current control material 19 that selectively reduces current density or selectively blocks current is provided in a region between the hole injection portion 15 and the electron injection portion 18 and corresponding to the second region 172C. As a result, when the element is driven, the carrier recombination probability is lower in the second region 172C than in the first region 171C, and the second region 172C can be put into a lower energy state than the first region 171C. Examples of materials used for the current control material include organic semiconductor materials having lower carrier mobility than other materials constituting the organic part, and insulating materials. For specific examples of insulating materials, see the description of the material for the convex body in the section "Layer structure of organic electroluminescent element" below.

[0022] <Embodiment II of Organic Electroluminescent Element> The organic electroluminescent element of this embodiment includes a hole injection section that injects holes, an electron injection section that injects electrons, and an organic section disposed between the hole injection section and the electron injection section, wherein the organic section includes a light-emitting layer that recombines holes and electrons to emit light, and when a voltage is applied between the hole injection section and the electron injection section, at least one of an electric field intensity periodic structure in which the electric field intensity periodically changes in a predetermined direction and a current intensity periodic structure in which the current intensity periodically changes in a predetermined direction is formed between the hole injection section and the electron injection section in a cross section (cross section in the XY direction) taken in a direction perpendicular to the thickness direction (e.g., the Z direction) of the organic section, and light from the light-emitting layer resonates in the electric field intensity periodic structure or the current intensity periodic structure. The "cross section" in the "cross section" referred to here may be, for example, a cross section at a position (position in the Z direction) where at least one of the electric field intensity and the current intensity appears to change periodically in the predetermined direction. In the organic electroluminescent element of this embodiment, the electric field intensity periodic structure or current intensity periodic structure formed between the hole injection part and the electron injection part functions as an optical resonator, so there is no need to provide an optical resonator separately from the hole injection part, the electron injection part, and the organic part. Therefore, for example, the number of parameters to be considered during simulations and quality inspections during element design can be reduced, making these tasks accurate, easy, and efficient.

[0023] In the organic electroluminescence element of the present embodiment, when a voltage is applied between the hole injection section and the electron injection section, only one of the electric field intensity periodic structure and the current intensity periodic structure may be formed, or both the electric field intensity periodic structure and the current intensity periodic structure may be formed. In one aspect of the present embodiment, when a voltage is applied between the hole injection section and the electron injection section, only the electric field intensity periodic structure of the electric field intensity periodic structure and the current intensity periodic structure is formed. In one aspect of the present embodiment, when a voltage is applied between the hole injection section and the electron injection section, only the current intensity periodic structure of the electric field intensity periodic structure and the current intensity periodic structure is formed. In one aspect of the present embodiment, when a voltage is applied between the hole injection section and the electron injection section, both the electric field intensity periodic structure and the current intensity periodic structure are formed. In one aspect of the present embodiment, when a voltage is applied between the hole injection section and the electron injection section, an electric field intensity periodic structure and a current intensity periodic structure having the same period are formed.

[0024] In one aspect of this embodiment, when a voltage is applied between the hole injection section and the electron injection section, the organic electroluminescent element can be configured such that, in a cross-section of the organic portion in the XY direction (XY cross-section), a periodic electric field structure is formed in which first a regions and second a regions having different electric field intensities are alternately arranged. Furthermore, in one aspect of this embodiment, the periodic electric field structure formed between the hole injection section and the electron injection section can be configured such that, when the organic portion is cut in the XY direction, a periodic structure in which first a regions and second a regions having different electric field intensities are alternately arranged appears in the cut section. The periodic electric field structure in the XY cross-section of the organic portion will be specifically described with reference to FIG. 18 . FIG. 18 shows an example of an organic electroluminescent element of the present invention, where (a) is a cross-section of the organic electroluminescent element cut in the XZ direction, and (b) is a plan view showing the periodic electric field structure in the cross-section of the organic electroluminescent element cut along line CC shown in (a). Here, the cross section of the organic electroluminescent element taken along line CC corresponds to the cross section of the organic portion in the XY direction (XY cross section), i.e., the "cross section" of the "cross section taken in a direction perpendicular to the thickness direction of the organic portion" in the present invention. In FIG. 18 , 21 denotes a hole injection portion, 22 denotes an organic portion, and 23 denotes an electron injection portion. For possible layer configurations of the organic portion, see the description in the "Layer configuration of organic electroluminescent element" section below. As shown in FIG. 18 , in the organic electroluminescent element of this example, when a voltage is applied between the hole injection portion 21 and the electron injection portion 23 and the organic portion 22 is cut along line CC along the XY direction, a periodic electric field intensity structure appears on the cut surface, in which 1a regions and 2a regions having different electric field strengths are alternately arranged, as shown in FIG. 18( b).

[0025] In one aspect of this embodiment, when a voltage is applied between the hole injection section and the electron injection section, the organic electroluminescent element can have a current intensity periodic structure in which first b regions and second b regions having different current intensities are alternately arranged in a cross section of the organic part in the XY direction (XY cross section). In other words, in one aspect of this embodiment, the current intensity periodic structure formed between the hole injection section and the electron injection section can be such that, when the organic part is cut in the XY direction, a periodic structure in which first b regions and second b regions having different current intensities are alternately arranged appears in the cross section. The current intensity periodic structure in the XY cross section of the organic part will be specifically described with reference to FIG. 18(c). FIG. 18(c) is a plan view showing the current intensity periodic structure in a cross section of an organic electroluminescent element having the current intensity periodic structure formed therein, taken along line CC in FIG. 18(a). Here, a cross section of the organic electroluminescent element taken along line C-C can correspond to a cross section of the organic portion in the XY direction (X-Y cross section), for example, the "cross section" of the "cross section taken along a direction perpendicular to the thickness direction of the organic portion" in this embodiment. In the organic electroluminescent element of this example, when a voltage is applied between the hole injection portion and the electron injection portion and the organic portion 22 is cut along line C-C along the X-Y direction, an electric field intensity periodic structure appears on the cut surface, in which 1b regions and 2b regions having different current intensities are alternately arranged, as shown in FIG.

[0026] 18(b) is an example, and the organic electroluminescent element of this embodiment should not be interpreted as being limited by this specific example. For example, in the electric field intensity periodic structure shown in FIG. 18(b), the 1a regions and the 2a regions are periodically arranged in only one direction, and in the current intensity periodic structure shown in FIG. 18(c), the 1b regions and the 2b regions are periodically arranged in only one direction. However, the electric field intensity periodic structure and the current intensity periodic structure formed in the organic electroluminescent element of this embodiment may be such that the 1a regions and the 2a regions, or the 1b regions and the 2b regions, are periodically arranged in two or more directions (for example, 2 to 8 directions) in the XY cross section, or may be such that they are periodically arranged in all directions in the XY cross section. Regarding the pattern of each periodic structure in the XY cross-sectional view, the description of the refractive index periodic structure pattern in the XY cross-sectional view in embodiment I (e.g., a striped periodic structure, a honeycomb periodic structure, a concentric periodic structure) can be referred to by replacing "first region" and "second region" with "1a region," "2a region," or "1b region," and "2b region," and by replacing "refractive index" with "electric field strength" or "current strength."

[0027] The first region a and the second region a in the XY cross-sectional view of the organic part are regions having different electric field strengths. The electric field strength ratio between the first region a and the second region a (electric field strength of the first region a / electric field strength of the second region a) can be, for example, one digit or more. The electric field strengths of the first region a and the second region a can be set appropriately.

[0028] In the first a region and the second a region, the electric field strength in the first a region may be higher than that in the second a region, or the electric field strength in the second a region may be higher than that in the first a region. Light from the light-emitting layer resonates in the region where the electric field strength is higher by interacting (reflecting, etc.) with the electric field to a greater extent. The light propagated through the electric field strength periodic structure is then emitted to the outside of the device, causing the organic electroluminescent device to emit light.

[0029] The 1b region and the 2b region in the XY cross-sectional view of the organic part are regions having different current intensities. The current intensity ratio between the 1b region and the 2b region (current intensity of the 1b region / current intensity of the 2b region) can be, for example, one digit or more. The current intensities of the 1b region and the 2b region can be set appropriately.

[0030] In the first region and the second region, the electric field strength in the first region may be higher than that in the second region, or the electric field strength in the second region may be higher than that in the first region. Light from the light-emitting layer resonates by interacting (reflecting, etc.) with the transported charges to a greater extent in the region where the current intensity is higher. The light propagated through the current intensity periodic structure is then emitted to the outside of the device, causing the organic electroluminescent device to emit light.

[0031] Here, in order to resonate the light from the light-emitting layer in the electric field intensity periodic structure, the pitch between the 1a region and the 2a region (the period of the electric field intensity periodic structure) can be set to satisfy the following Bragg equation: Furthermore, in order to resonate the light from the light-emitting layer in the current intensity periodic structure, the pitch between the 1b region and the 2b region (the period of the current intensity periodic structure) can be set to satisfy the following Bragg equation: mλ Ｂｒａｇｇ = 2n ｅｆｆ Λ ｍ In the formula, m is the diffraction order, λ Ｂｒａｇｇ is the Bragg wavelength, n ｅｆｆ is the effective refractive index of the organic part that serves as the optical waveguide, Λ ｍ represents the pitch of the electric field intensity periodic structure or the current intensity periodic structure, respectively. m is a positive integer, and may be selected from integers 1 to 3, for example, or may be 1. As shown in the above formula, the Bragg wavelength λ Ｂｒａｇｇ is the pitch Λ of the electric field intensity periodic structure or current intensity periodic structure ｍ Therefore, the value determined by the target emission wavelength (λ Ｂｒａｇｇ ) corresponding to the pitch (Λ ｍ By designing the element so that at least one of a field intensity periodic structure and a current intensity periodic structure is formed in the organic electroluminescent element, it is possible to obtain an organic electroluminescent element that emits light at a desired emission wavelength.

[0032] The electric field intensity periodic structure or the current intensity periodic structure can be formed by using an electrode layer having a conductive periodic structure as the electrode layer constituting the hole injection section or the electron injection section, or by using an organic layer having a conductive periodic structure as the organic layer constituting the organic section. The electric field intensity periodic structure or the current intensity periodic structure can also be formed by adding a layer between the hole injection section and the organic section or between the electron injection section and the organic section, and imparting a conductive periodic structure to this layer. Here, "conductivity" refers to the ability of a substance itself to conduct electricity, and electrical conductivity (unit: S / m) measured using a general measuring instrument can be used as an indicator. Below, we will explain embodiments of an organic electroluminescent element using an electrode layer having a conductive periodic structure and embodiments of an organic electroluminescent element using an organic layer having a conductive periodic structure.

[0033] (Aspects of Organic Electroluminescent Device Using Electrode Layer Having Conductive Periodic Structure) In one aspect of this embodiment, the organic electroluminescent device includes, in at least one of the hole injection section and the electron injection section, an electrode layer having a conductive periodic structure formed so that the conductivity varies periodically in a predetermined direction in a plan view (XY plan view) perpendicular to the thickness direction (Z direction). The "plane" in "plan view" here can refer to, for example, a plane at a position (position in the Z direction) where the periodic variation in conductivity in the predetermined direction can be observed, and can also be referred to as the interface between the electrode layer and the organic section. In an organic electroluminescent device including an electrode layer having such a conductive periodic structure in at least one of the hole injection section and the electron injection section, when a voltage is applied between the hole injection section and the electron injection section, the amount of electricity is greater in a region of high conductivity (high conductivity region) of the electrode layer than in a region of low conductivity (low conductivity region) of the electrode layer, and the electric field strength between the hole injection section and the electron injection section is higher in a region corresponding to the high conductivity region than in a region corresponding to the low conductivity region. As a result, an electric field intensity periodic structure is formed between the hole injection section and the electron injection section with a period corresponding to the conductive periodic structure of the electrode layer. Furthermore, at this time, the current intensity is higher in the region with high electric field intensity than in the region with low electric field intensity. This allows a current intensity periodic structure to be formed with a period corresponding to the period of the conductive periodic structure of the electrode layer.

[0034] The electrode layer may have a conductive periodic structure in either one or both of the hole injection section and the electron injection section. In one aspect of this embodiment, of the hole injection section and the electron injection section, only the hole injection section includes an electrode layer having a conductive periodic structure. In one aspect of this embodiment, of the hole injection section and the electron injection section, only the electron injection section includes an electrode layer having a conductive periodic structure. In one aspect of this embodiment, both the hole injection section and the electron injection section include electrode layers having a conductive periodic structure. In one aspect of this embodiment, the electrode layer of the hole injection section and the electrode layer of the electron injection section have conductive periodic structures with the same period.

[0035] As shown in Figure 19, the electrode layer 24 having a conductive periodic structure can have a structure in which, for example, first electrode regions 241 and second electrode regions 242 having different conductivities are alternately arranged at a constant pitch. In such an electrode layer 24, end faces 241C of the first electrode regions 241 and end faces 242C of the second electrode regions 242 are alternately arranged in a plane in the XY direction to form a conductive periodic structure. As a result, in the organic electroluminescent element, when a voltage is applied between the hole injection section and the electron injection section, an electric field intensity periodic structure is formed with a period corresponding to the period of the periodic structure consisting of the end faces 241C and 242C. Hereinafter, the region corresponding to the end face 241C of the first electrode region 241 may be referred to as the "1c region," and the region corresponding to the end face 242C of the second electrode region 242 may be referred to as the "2c region." Regarding the pattern of the conductive periodic structure in the XY planar view of the electrode layer, the description of the pattern of the refractive index periodic structure in the XY cross-sectional view in embodiment I (e.g., a striped periodic structure, a honeycomb periodic structure, a concentric periodic structure) can be referred to by replacing "first region" and "second region" with "first c region" and "second c region", and by replacing "refractive index" with "conductivity".

[0036] The first electrode region and the second electrode region, which have different conductivities from each other, can be formed by controlling the conductivity of at least one of the 1c region and the 2c region of the electrode layer. In one aspect of this embodiment, a dopant that imparts conductivity is used as the dopant that controls conductivity, and the dopant is selectively added to the 1c region of the electrode layer to form the first electrode region, and the region between adjacent first electrode regions is called the second electrode region. In this case, since the dopant that imparts conductivity is added only to the first electrode region of the first and second electrode regions, the first electrode region has a higher conductivity than the second electrode region. In one aspect of this embodiment, a dopant that imparts conductivity is used as the dopant that controls conductivity, and the dopant is selectively added to the 2c region of the electrode layer to form the second electrode region, and the region between adjacent second electrode regions is called the first electrode region. In this case, since the dopant that imparts conductivity is added only to the second electrode region of the first and second electrode regions, the second electrode region has a higher conductivity than the first electrode region. In one aspect of this embodiment, a dopant that imparts conductivity is used as the dopant that controls conductivity, and different concentrations of the dopant are added to the first and second electrode regions of the electrode layer. In this case, the region with a higher dopant concentration has higher conductivity than the other of the first and second electrode regions. The first and second electrode regions doped with the dopant have the dopant present at least on their end faces, and a conductive periodic structure is formed in the XY plane of the electrode layer between the end face and the end face of the other electrode region. Therefore, the first and second electrode regions doped with the dopant may be doped throughout their entire regions, or may be doped to a depth intermediate between the first and second electrode regions and not doped in deeper regions.

[0037] The base material of the electrode layer to which the dopant is added is, for example, indium oxide (In ２ O ３ )-based transparent conductive film, tin oxide (SnO ２Examples of such transparent conductive films include indium oxide (ITO)-based transparent conductive films and zinc oxide (ZnO)-based transparent conductive films. In these transparent conductive films, the conductivity of a specific region can be selectively controlled by adding a dopant that controls the conductivity of that region. Specific examples of dopants include tin for indium oxide-based transparent conductive films, antimony and fluorine for tin oxide-based transparent conductive films, and aluminum and gallium for zinc oxide-based transparent conductive films. The amount of dopant added to the first electrode region and the second electrode region of the transparent conductive film can be determined appropriately. Furthermore, conductive polymer films of conjugated polymers can also be used as the base material for the electrode layer to which the dopant is added. Examples of conjugated polymers that can be used in the conductive polymer film include polyacetylene, poly(p-phenylene vinylene), polypyrrole, polythiophene, polyaniline, and poly(p-phenylene sulfide). These conjugated polymers may be used alone or in combination of two or more. In a conductive polymer film of a conjugated polymer, the conductivity of a specific region can be selectively controlled by adding a dopant that controls the conductivity to that region. Furthermore, when an acceptor dopant is added to the conductive polymer film, holes are generated, causing the film to function as an anode injection region. When a donor dopant is added, electrons are supplied, causing the film to function as an electron injection region. Examples of acceptor dopants include halogens (e.g., iodine, bromine) and Lewis acids (e.g., arsenic pentafluoride, sulfuric acid). Examples of donor dopants include alkali metals (e.g., sodium, potassium) and Lewis bases (e.g., ammonia, hydrazine). Other known dopants can also be appropriately selected and used. When dopants are added to the first electrode region and the second electrode region of the conductive polymer film, the amount of dopant can be appropriately determined.

[0038] The first electrode region and the second electrode region of the electrode layer are regions with different electrical conductivities. The ratio of the electrical conductivities of the materials constituting the first electrode region and the second electrode region (electrical conductivity of the material constituting the first electrode region / electrical conductivity of the material constituting the second electrode region) may be, for example, one digit or more. The electrical conductivities of the materials constituting the first electrode region and the second electrode region may be appropriately set. The conductivity of the first electrode region may be higher than that of the second electrode region, or the conductivity of the second electrode region may be higher than that of the first electrode region. Alternatively, the first electrode region may be a low-conductivity region and the second electrode region a high-conductivity region, or the first electrode region may be a high-conductivity region and the second electrode region a low-conductivity region. The electric field strength between the hole injection portion and the electron injection portion is higher in the region corresponding to the high-conductivity region than in the region corresponding to the low-conductivity region, and light from the light-emitting layer interacts (e.g., reflects) with the electric field to a greater extent in the region with higher electric field strength, causing resonance.

[0039] (Aspects of Organic Electroluminescent Device Having a Conductive Periodic Structure in the Organic Portion) In one aspect of this embodiment, the organic portion of the organic electroluminescent device includes an organic layer having a conductive periodic structure formed so that the conductivity varies periodically in a predetermined direction when viewed in a plan view (XY plan view) perpendicular to the thickness direction (Z direction). The "plane" in "plan view" here can refer to, for example, a plane or cross section at a position (position in the Z direction) where the periodic variation in conductivity in the predetermined direction can be observed. It may be the interface between the organic layer and an adjacent layer, or a cross section of the organic layer cut in the XY direction. In an organic electroluminescent device including an organic layer having a conductive periodic structure in the organic portion, when a voltage is applied between the hole injection portion and the electron injection portion, the current intensity is higher in the high conductivity region (high conductivity region) of the organic layer than in the low conductivity region (low conductivity region). This forms a current intensity periodic structure with a period corresponding to the conductive periodic structure of the organic layer. Here, the organic portion is composed of at least one organic layer. The organic portion may have a single-layer structure consisting of a single organic layer, or a laminate structure in which two or more organic layers are stacked. When the organic part has a single layer structure consisting of one organic layer, the organic layer has a conductive periodic structure. When the organic part has a laminated structure in which two or more organic layers are laminated, only one of the layers may have a conductive periodic structure, or two or more of the layers may have a conductive periodic structure. In one aspect of this embodiment, the organic part has a laminated structure in which two or more organic layers are laminated, and only one of the layers has a conductive periodic structure. In one aspect of this embodiment, the organic part has a laminated structure in which two or more organic layers are laminated, and at least two of the organic layers have a conductive periodic structure. In one aspect of this embodiment, the organic part has two or more organic layers having a conductive periodic structure, and the periods of the conductive periodic structures of these organic layers are the same. For possible layer structures of the organic part, please refer to the description in the section "Layer structure of organic electroluminescent element" below.

[0040] 20 , the organic layer 25 having a conductive periodic structure can have, for example, a structure in which first organic regions 251 and second organic regions 252 having different conductivities are alternately arranged at a constant pitch. In such an organic layer 25, end faces 251C of the first organic regions 251 and end faces 252C of the second organic regions 252 are alternately arranged in a plane along the XY direction, forming a conductive periodic structure. Furthermore, in such an organic layer 25, cross sections of the first organic regions 251 and cross sections of the second organic regions 252 are alternately arranged in a cross section cut in the XY direction (XY cross section), forming a conductive periodic structure. As a result, in the organic electroluminescent element, when a voltage is applied between the hole injection section and the electron injection section, a current intensity periodic structure is formed with a period corresponding to the conductive periodic structure of the organic layer 25. Hereinafter, the region corresponding to the end face 251C of the first organic region 251 may be referred to as the "first d region," and the region corresponding to the end face 252C of the second organic region 252 may be referred to as the "second d region." Regarding the pattern of the conductive periodic structure in the XY planar view of the organic layer, the description of the pattern of the refractive index periodic structure in the XY cross-sectional view in the first embodiment (for example, a striped periodic structure, a honeycomb periodic structure, or a concentric periodic structure) can be referred to by replacing the "first region" and "second region" with the "first d region" and "second d region," and replacing "refractive index" with "conductivity."

[0041] The first organic region and the second organic region, which have different conductivities from each other, can be formed by controlling the conductivity of at least one of the first d region and the second d region of the organic layer. In one aspect of this embodiment, a dopant that imparts conductivity is used as the dopant that controls conductivity, and the dopant is selectively added to the first d region of the organic layer to form the first organic region, and the region between adjacent first organic regions is called the second organic region. In this case, since the dopant that imparts conductivity is added only to the first organic region of the first and second organic regions, the first organic region has a higher conductivity than the second organic region. In one aspect of this embodiment, a dopant that imparts conductivity is used as the dopant that controls conductivity, and the dopant is selectively added to the second d region of the organic layer to form the second organic region, and the region between adjacent second organic regions is called the first organic region. In this case, since the dopant that imparts conductivity is added only to the second organic region of the first and second organic regions, the second organic region has a higher conductivity than the first organic region. In one aspect of this embodiment, a dopant that imparts conductivity is used as the dopant that controls conductivity, and different concentrations of the dopant are added to the first d region and the second d region of the organic layer to form the first organic region and the second organic region. In this case, the region with a higher dopant concentration among the first and second organic regions has higher conductivity than the other region. The first and second organic regions doped with the dopant have the dopant present at least on their end faces, and a conductive periodic structure is formed in the XY plane of the organic layer by the end faces and the end faces of the other organic region. Therefore, the first and second organic regions doped with the dopant may be doped throughout their entire regions, or may be doped to a depth intermediate between the first and second organic regions and not doped in deeper regions.

[0042] For examples of organic materials that can be used in the organic layer, please refer to the description of the materials for the organic layer (e.g., hole injection layer, hole transport layer, electron blocking layer, light-emitting layer, hole blocking layer, electron transport layer, and electron injection layer) listed in the section "Layer structure of organic electroluminescent device" below. In organic layers formed from these organic materials, the conductivity of a specific region can be selectively controlled by adding a dopant that controls the conductivity to that region. For specific examples of dopants and their addition concentrations, please refer to the description of dopants that can be added to the conductive polymer film above.

[0043] The first organic region and the second organic region of the organic layer are regions with different electrical conductivities. The ratio of the electrical conductivities of the materials constituting the first organic region and the second organic region (electrical conductivity of the material constituting the first organic region / electrical conductivity of the material constituting the second organic region) may be, for example, one digit or more. The electrical conductivities of the materials constituting the first organic region and the second organic region may be appropriately set. The electrical conductivity of the first organic region may be higher than that of the second organic region, or the electrical conductivity of the second organic region may be higher than that of the first organic region. In other words, the first organic region may be a low-conductivity region and the second organic region may be a high-conductivity region, or the first organic region may be a high-conductivity region and the second organic region may be a low-conductivity region. The current intensity between the hole injection portion and the electron injection portion is higher in the region corresponding to the high-conductivity region than in the region corresponding to the low-conductivity region, and light from the light-emitting layer interacts (e.g., reflects) more strongly with the transport charges in the region with higher current intensity, causing resonance.

[0044] (Control of the Emitted Color of the Organic Electroluminescence Element of the Second Embodiment) As described above, the Bragg wavelength λ Ｂｒａｇｇ is the pitch (Λ) of the electric field intensity periodic structure or the current intensity periodic structure. ｍ ) is a value determined by the target emission wavelength (λ Ｂｒａｇｇ ) corresponding to the pitch (Λ ｍ), an organic electroluminescence element that emits light at a desired emission wavelength can be obtained by designing the element so that a periodic electric field intensity structure or a periodic current intensity structure is formed. For example, the organic electroluminescence element of this embodiment can be obtained by designing the element so that a periodic electric field intensity structure or a periodic current intensity structure is formed. ｍ By controlling the wavelength of the organic electroluminescent element according to the present embodiment, it is possible to make the organic electroluminescent element emit light at a wavelength in the visible region (for example, 400 to 780 nm), in the infrared region (for example, 780 nm to 2 μm), or in the ultraviolet region (for example, 280 to 400 nm). ｍ By controlling the wavelength of the organic electroluminescent element, it is possible to make it emit light at a wavelength in the red region (for example, 620 to 780 nm), in the green region (for example, 490 to 575 nm), or in the blue region (for example, 400 to 490 nm). In one aspect of this embodiment, the emission wavelength of the organic electroluminescent element is in the red region, and the material of the organic portion that becomes the optical waveguide can contain, for example, DCM as a dopant, and the pitch Λ of the conductive periodic structure of the electrode layer or the organic layer ｍ In one aspect of this embodiment, the emission wavelength of the organic electroluminescence element is in the green region, and the material of the organic portion that serves as the optical waveguide may contain, for example, a BTD skeleton, a fluorene skeleton, or the like, and the pitch Λ of the conductive periodic structure of the electrode layer or the organic layer ｍ In one aspect of this embodiment, the emission wavelength of the organic electroluminescence element is in the blue region, the material of the organic portion that serves as the optical waveguide can be, for example, a material containing BSBCz, and the pitch Λ of the conductive periodic structure of the electrode layer or the organic layer can be ｍ can be, for example, 250 to 270 nm.

[0045] [Usefulness of Organic Electroluminescent Elements] As described above, the organic electroluminescent elements of Embodiments I and II can be used as light-emitting elements that emit light of a specific wavelength. Furthermore, when the organic electroluminescent elements of Embodiments I and II receive light of a specific wavelength, the light is amplified by resonation in the refractive index periodic structure, the electric field intensity periodic structure, or the current intensity periodic structure, and can be detected as amplified light. Therefore, these organic electroluminescent elements can be applied to light-receiving sensors that emit light of a specific wavelength and selectively receive light of the same wavelength as the emitted light (e.g., reflected light or transmitted light from a detected object that receives the emitted light). As an example of a light-receiving sensor, FIG. 21 shows a light-receiving sensor using the organic electroluminescent element of Embodiment II. This light-receiving sensor can be a reflective light-receiving sensor that detects the state of a detected object by irradiating light from the light-emitting unit onto the detected object and receiving light reflected from the detected object with the light-receiving unit. Here, the light-emitting section and the light-receiving section are configured as organic electroluminescent elements in which the hole injection section 21 is configured with the electrode layer 24 shown in FIG. 19 , i.e., organic electroluminescent elements in which an electric field intensity periodic structure is formed by applying a voltage between the hole injection section and the electron injection section. The light-emitting section and the light-receiving section can be organic electroluminescent elements in which at least one of an electric field intensity periodic structure and a current intensity periodic structure is formed by applying a voltage between the hole injection section and the electron injection section. Organic electroluminescent elements having a refractive index periodic structure in the organic section (e.g., the organic electroluminescent elements shown in FIGS. 1 and 17 ) can also be used. Here, the organic electroluminescent elements used in the light-emitting section and the light-receiving section can be designed so that the periods of the periodic structures of the electric field intensity periodic structure, the current intensity periodic structure, and the refractive index periodic structure possessed by the elements are identical to each other. Furthermore, a light-receiving sensor using the organic electroluminescence element of embodiment I or embodiment II may be a transmission-type light-receiving sensor that has a light-receiving unit on the opposite side of the light-emitting unit from the detection object, irradiates light from the light-emitting unit to the detection object, and receives light transmitted from the detection object at the light-receiving unit.In the light-receiving sensor, the light emitted by the organic electroluminescent element and the light selectively received are not particularly limited and may be light in the visible region, infrared region, or ultraviolet region. In one aspect of this embodiment, the light emitted by the organic electroluminescent element and the light selectively received may be at least one of light in the red region, light in the green region, and light in the blue region. In one aspect of this embodiment, the light emitted by the organic electroluminescent element and the light selectively received may be light in the infrared region. A light-receiving sensor using the organic electroluminescent element of Embodiment I or II as the light-emitting section and the light-receiving section can be applied to, for example, a display-integrated scanner, a display-integrated fingerprint sensor, etc., thereby enabling these devices to have an improved S / N ratio, higher performance, and lower power consumption.

[0046] [Layer Structure of Organic Electroluminescent Element] The organic electroluminescent element of this embodiment includes a hole injection portion that injects holes, an electron injection portion that injects electrons, and an organic portion disposed between the hole injection portion and the electron injection portion, and includes a light-emitting layer in which the organic portion recombines holes and electrons to emit light. In this embodiment, the term "organic portion" refers to a portion containing, for example, 70% by weight or more of an organic compound, and the term "organic compound" refers to a compound containing, for example, one or more carbon atoms. Examples of organic compounds that can be used include those consisting only of atoms selected from the group consisting of carbon, hydrogen, oxygen, nitrogen, boron, and halogen atoms. The organic compound used for the "organic portion" in this embodiment is, for example, an organic compound used as an organic semiconductor material. Furthermore, in this specification, the terms "organic material" and "organic portion" as used in the organic layer constituting the organic portion, as well as "organic material" in the terms "first organic material" and "second organic material," refer to a material containing, for example, 70% by weight or more of an organic compound. For an explanation of the "organic compound," please refer to the description of the "organic compound" in the "organic layer" section above. In this embodiment, the organic compounds used in the organic material, first organic material, and second organic material are, for example, organic compounds serving as organic semiconductor materials. The organic portion may have a single-layer structure or a laminated structure. In the case of a laminated structure, it may be a two-layer laminate, a three-layer laminate, or a four-layer or more laminate, for example, a two-layer laminate or a three-layer or more laminate. When the two or more organic layers are two layers, namely, a first organic layer and an emitting layer (second organic layer), the first organic layer can have a lower refractive index than the emitting layer. Furthermore, when the two or more organic layers include at least a first organic layer, an emitting layer (second organic layer), and a third organic layer, and the first organic layer and the emitting layer are adjacent to each other and the emitting layer and the third organic layer are adjacent to each other, the first organic layer and the third organic layer can have a lower refractive index than the emitting layer.

[0047] Examples of organic layers other than the light-emitting layer that may be included in the two or more organic layers include a hole injection layer, a hole transport layer, an electron blocking layer, a hole blocking layer, an electron transport layer, and an electron injection layer. The organic portion may also include an electrode layer. For example, the electrode layer may be an electrode made of an inorganic material. Furthermore, when the hole injection portion or the electron injection portion is an electrode made of an organic conductive material, this electrode may also be included in the two or more organic layers. In one aspect of this embodiment, the organic portion consists of at least one organic layer. In one aspect of the present invention, the organic portion consists of at least one organic layer and at least one inorganic electrode layer (e.g., one inorganic electrode layer, e.g., two inorganic electrode layers). In one aspect of this embodiment, the organic portion includes, in addition to the light-emitting layer, one or more layers selected from a hole transport layer, a hole injection layer, an electron blocking layer, a hole blocking layer, an electron injection layer, and an electron transport layer. The hole transport layer may be a hole injection transport layer having a hole injection function, and the electron transport layer may be an electron injection transport layer having an electron injection function. The hole injection layer, hole transport layer, electron blocking layer, light-emitting layer, hole blocking layer, electron transport layer, and electron injection layer may each be composed of a single layer or two or more layers. Specific examples of the layer structure of the organic electroluminescent element include a layer structure in which a substrate / hole injection part / hole injection layer / hole transport layer / light-emitting layer / hole blocking layer / electron transport layer / electron injection layer / electron injection part are laminated in this order, a layer structure in which a substrate / electron injection part / electron injection layer / electron transport layer / hole blocking layer / light-emitting layer / hole transport layer / hole injection layer / hole injection part are laminated in this order, a layer structure in which at least one organic layer (e.g., the hole blocking layer) is removed from these layer structures, and a layer structure in which at least one organic layer (e.g., the electron blocking layer) is added to these layer structures.Here, when the refractive index periodic structure of the organic electroluminescent element has a laminated structure in which at least two organic layers each having a periodic uneven shape are laminated, and the laminated structure includes adjacent organic layers (a first organic layer and a second organic layer) having different refractive indices, examples of combinations of the first organic layer and the second organic layer include a combination of two hole transport layers having different refractive indices, a combination of two light-emitting layers having different refractive indices, a combination of two electron transport layers having different refractive indices, a combination of a hole transport layer and a light-emitting layer, and a combination of a light-emitting layer and an electron transport layer. The combination of the first organic layer and the second organic layer is not limited to these specific examples, as long as the refractive indices are different. Furthermore, when the first organic layer of the first organic layer and the second organic layer is located on the hole injection portion side, another organic layer (e.g., a hole transport layer or a hole injection layer) may be interposed between the first organic layer and the hole injection portion, and another organic layer (e.g., an electron transport layer or an electron injection layer) may be interposed between the second organic layer and the electron injection portion. When the first organic layer of the first organic layer and the second organic layer is on the electron injection part side, another organic layer (e.g., an electron transport layer or an electron injection layer) may be interposed between the first organic layer and the electron injection part, and another organic layer (e.g., a hole transport layer or a hole injection layer) may be interposed between the second organic layer and the hole injection part. Each component and each layer of the organic electroluminescent element of this embodiment will be described in detail below.

[0048] (Substrate) The organic electroluminescent element of this embodiment can be configured such that each member and each layer is supported on a substrate. When the organic electroluminescent element is configured to extract light from the substrate side, a substrate that is translucent to light is used as the substrate, and a transparent substrate made of, for example, glass, transparent plastic, quartz, etc. can be used. On the other hand, when the organic electroluminescent element is configured to extract light from the side opposite the substrate, the substrate is not particularly limited, and in addition to the above transparent substrates, substrates made of silicon, paper, or cloth can also be used.

[0049] (Hole injection section) The hole injection section has the function of injecting holes. For example, when a light-emitting layer is provided adjacent to the hole injection section, holes are directly injected from the hole injection section into the light-emitting layer. Furthermore, when one or more layers are provided between the light-emitting layer and the hole injection section, holes are injected from the hole injection section into one of the one or more layers that is adjacent to the hole injection section, and the holes transported through the one or more layers are injected into the light-emitting layer.

[0050] In one aspect of this embodiment, the hole injection portion is an electrode, for example, a transparent electrode. The electrode (hereinafter referred to as "anode") that is the hole injection portion can be made of, for example, a metal, alloy, electrically conductive compound, or a mixture thereof that has a large work function (4 eV or more). Specific examples of such electrode materials include metals such as Au, CuI, indium tin oxide (ITO), and SnO. ２ , ZnO, TiN, and other conductive transparent materials. ２ O ３Materials capable of producing amorphous, transparent conductive films, such as ZnO, may also be used. The anode can be formed by depositing these electrode materials by methods such as vapor deposition or sputtering. Alternatively, a desired pattern may be formed on the formed thin film by photolithography, or when pattern precision is not required (approximately 100 μm or more), a pattern may be formed through a mask of the desired shape during vapor deposition or sputtering of the electrode material. Alternatively, when a coatable material such as an organic conductive compound is used, wet film formation methods such as printing or coating can also be used. However, when the organic electroluminescent element is configured to extract light by transmitting it through the anode, the anode must be transparent. Specifically, to form a transparent anode, for example, the above-mentioned conductive transparent material can be used as the anode, a thin film formed of a metal or alloy with a thickness of 5 to 100 nm can be used as the anode, or an electrode having the DMD structure described below can be used as the anode. The thickness of the metal or alloy thin film is, for example, 40 nm or less, for example, 5 to 30 nm, for example, 12 to 25 nm. The sheet resistance as an anode is, for example, several hundred Ω / □ or less. Furthermore, the film thickness, although depending on the material, is selected from the range of, for example, 10 to 1000 nm, for example, 10 to 200 nm.

[0051] (Electron Injection Section) The electron injection section has the function of injecting electrons. For example, when a light-emitting layer is provided adjacent to the electron injection section, electrons are directly injected from the electron injection section into the light-emitting layer. Furthermore, when one or more layers are present between the light-emitting layer and the electron injection section, electrons are injected from the electron injection section into one of the one or more layers that is adjacent to the electron injection section, and the electrons transported through the one or more layers are injected into the light-emitting layer.

[0052] In one aspect of this embodiment, the electron injection part is an electrode, for example, a metal electrode. The material of the metal electrode may be any of a simple metal element, a mixture of two or more simple metal elements, an alloy of two or more metal elements, a mixture of a simple metal element and an alloy, and a mixture of two or more alloys. For the electrode serving as the electron injection part (hereinafter referred to as the "cathode"), a metal (referred to as an electron injection metal) or alloy having a smaller work function than the electrode material used for the anode can be used. Furthermore, an electrically conductive compound or a mixture thereof can also be used as the electrode material for the cathode. Specific examples of such cathode materials include sodium, sodium-potassium alloy, magnesium, lithium, a magnesium / copper mixture, a magnesium / silver mixture, a magnesium / aluminum mixture, a magnesium / indium mixture, and aluminum / aluminum oxide (Al ２ O ３ Among these, for example, in terms of electron injection property and durability against oxidation, etc., a mixture of an electron injection metal and a second metal which is a metal having a larger work function value and is more stable than the electron injection metal can be used, and examples thereof include a magnesium / silver mixture, a magnesium / aluminum mixture, a magnesium / indium mixture, an aluminum / aluminum oxide (Al ２ O ３) mixture, lithium / aluminum mixture, aluminum, etc. can be used. Furthermore, a coated metal film, in which a coating of lithium fluoride or the like is provided on the surface of a thin film formed from an electron-injecting metal, can also be used as the cathode. The cathode can be formed by depositing these electrode materials by methods such as vapor deposition or sputtering. Note that, when the organic electroluminescence element is configured to extract light by transmitting light through the cathode, the cathode can be made transparent. To form a transparent cathode, a thin film formed from the above-mentioned electrode material to a thickness of 5 to 100 nm (e.g., 40 nm or less, e.g., 5 to 30 nm, e.g., 12 to 25 nm) can be used as the cathode; a laminated structure (e.g., an ITO / Al / LiF laminated structure) in which the above-mentioned coated metal film is laminated on a thin film of a conductive transparent material exemplified as the anode material can be used as the cathode; or an electrode having the DMD structure described below can be used as the cathode. The sheet resistance of the cathode is, for example, several hundred Ω / □ or less, and the film thickness is usually selected in the range of 10 nm to 5 μm, for example, 50 to 200 nm.

[0053] In one aspect of this embodiment, at least one of the electron injection part and the hole injection part is an electrode having a visible light transmittance of 10% or more, for example, 50% or more, for example, 80% or more, or for example, 90% or more.

[0054] (Light-Emitting Layer) The light-emitting layer is a layer that emits light after excitons are generated by the recombination of holes and electrons injected from the hole injection portion and the electron injection portion, respectively. The light-emitting layer may be composed solely of a light-emitting material, or may be a layer in which a host material is doped with the light-emitting material. The light-emitting layer may also contain a dopant material. In one aspect of this embodiment, the light-emitting layer is a layer composed solely of a light-emitting material. In one aspect of this embodiment, the light-emitting layer is a layer in which a host material is doped with the light-emitting material. In one aspect of this embodiment, the light-emitting layer is a layer in which a light-emitting material and a dopant material are mixed. In one aspect of this embodiment, the light-emitting layer is a layer in which a host material is doped with the light-emitting material and a dopant material. Known light-emitting materials can be used, and may be any of fluorescent materials, delayed fluorescent materials, and phosphorescent materials, or may be laser oscillation materials. The laser oscillation material is a light-emitting material that can cause stimulated emission by the incidence of light after excitons are generated by the recombination of holes and electrons, forming a population inversion. By using a laser oscillation material as the light-emitting material, the organic electroluminescent device of this embodiment can be configured as an organic solid-state semiconductor laser. In one aspect of this embodiment, the organic electroluminescent device of the present invention is an organic solid-state semiconductor laser, and the light-emitting layer contains a laser oscillation material. When a laser oscillation material is used as the light-emitting material, the light-emitting layer may be composed solely of the laser oscillation material, or may be a layer in which the laser oscillation material is doped into a host material. The light-emitting layer may also contain a laser oscillation material and a dopant material. Examples of dopant materials include a light-emitting material and a triplet quencher. Doping the light-emitting layer with a light-emitting material can control the wavelength and color of light emitted by the light-emitting layer. Furthermore, doping the light-emitting layer with a triplet quencher can suppress the accumulation of triplet excitons in the light-emitting layer, thereby suppressing the generation of higher-order excited states due to collisions between triplet excitons and the degradation of excited molecules caused by these higher-order excited states. As a result, the light-emitting efficiency can be improved. In one aspect of this embodiment, the light-emitting layer is composed solely of the laser oscillation material. In one aspect of this embodiment, the light-emitting layer is a layer formed by doping a lasing material into a host material.In one aspect of this embodiment, the light-emitting layer is a layer formed by mixing a lasing material and a dopant material. In one aspect of this embodiment, the light-emitting layer is a layer formed by doping a host material with the lasing material and the dopant material. In one aspect of this embodiment, the dopant material is an organic compound. In one aspect of this embodiment, the dopant material comprises an emissive material. In one aspect of this embodiment, the dopant material comprises a triplet quencher. In one aspect of this embodiment, the dopant material comprises an emissive material and a triplet quencher.

[0055] The laser oscillation material can be selected from organic compounds having at least one stilbene unit, where the stilbene unit has the following structure, at least one hydrogen atom of which may be substituted with a substituent:

[0056]

[0057] In one aspect of this embodiment, the laser oscillation material is selected from organic compounds having two or more stilbene units. In the two or more stilbene units, the phenyl groups of adjacent stilbene units may be linked by a single bond at the 4- and 4'-positions, or may be linked by a single bond at the 4- and 4'-positions and a methylene group at the 3- and 3'-positions to form a fluorene ring. At least one hydrogen atom of the benzene ring constituting the stilbene unit may be substituted with a substituent (e.g., an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 15 carbon atoms). Furthermore, the hydrogen atom at the 9-position (methylene group) of the fluorene ring may be substituted with two alkyl groups (e.g., having 1 to 10 carbon atoms, e.g., 6 carbon atoms), and a hydrocarbon ring such as a fluorene ring may be spiro-bonded to the 9-position.

[0058] Specific examples of laser oscillation materials that can be used in this embodiment are listed below. However, the laser oscillation materials that can be used in this embodiment should not be construed as being limited by these specific examples. First, a specific example of a laser oscillation material having a stilbene unit is 4,4'-bis[(N-carbazole)styryl]biphenyl (BSBCz) represented by the following formula. In one aspect of this embodiment, the light-emitting layer contains BSBCz. In one aspect of this embodiment, the light-emitting layer is a layer composed only of BSBCz. In one aspect of the present invention, the light-emitting layer is a layer formed by doping BSBCz into a host material. The layer formed by doping BSBCz into a host material may further contain a dopant material.

[0059]

[0060] Examples of laser oscillation materials having a stilbene unit include the following compound and a polymer having the following repeating structure: １ and R ２ represents an alkyl group having 1 to 10 carbon atoms, such as a hexyl group. n and m each independently represent an integer of 2 to 20. n and m may be the same or different.

[0061]

[0062] The laser oscillation material can also be selected from organic compounds having at least one fluorene ring. Examples of laser oscillation materials having a fluorene ring include the following compounds and polymers having the following repeating structures: In the following formulas, R represents an alkyl group having 1 to 10 carbon atoms, such as a hexyl group; Me represents a methyl group, hexyl represents a hexyl group, and Oct represents an octyl group; n represents an integer from 2 to 30, such as 2, 3, 4, 5, or 6. Note that compounds having both a stilbene unit and a fluorene ring are shown above as specific examples of laser oscillation materials having a stilbene unit.

[0063]

[0064] The laser oscillation material can also be selected from organic compounds having at least one condensed polycyclic structure (julolidine ring) shown below.

[0065]

[0066] Examples of laser oscillation materials having a julolidine ring include the following compounds.

[0067] By using, for example, a material other than a polymer (a polymer of a monomer) among the above laser oscillation materials, the light emitting layer can be easily formed by vapor deposition.

[0068] The light-emitting material used as the dopant material can be, for example, a light-emitting organic compound, and may be any of a fluorescent material, a delayed fluorescent material, and a phosphorescent material. In this specification, a "fluorescent material" refers to a light-emitting material whose fluorescent emission intensity is higher than its phosphorescence emission intensity when observed at 20°C, and a "phosphorescent material" refers to a light-emitting material whose phosphorescence emission intensity is higher than its fluorescence emission intensity when observed at 20°C. A "delayed fluorescent material" refers to a material in which both fluorescence with a short emission lifetime and fluorescence with a long emission lifetime (delayed fluorescence) are observed at 20°C. Ordinary fluorescence (fluorescence other than delayed fluorescence) has an emission lifetime on the order of nanoseconds, while phosphorescence usually has an emission lifetime on the order of milliseconds. Therefore, fluorescence and phosphorescence can be distinguished by their emission lifetimes. Furthermore, light-emitting organic compounds other than organometallic complexes are ordinary fluorescent materials or delayed fluorescent materials. Furthermore, the light-emitting material used as the dopant material may be an organic compound known as an optical gain medium. However, the compound used as the light-emitting material must be different from the compound used as the laser oscillation material in the organic electroluminescent device. The configuration and driving conditions of the optical resonator of the organic electroluminescence element used in the present invention are designed based on the conditions (e.g., emission wavelength and oscillation threshold) of the organic compound selected as the laser oscillation material so that the organic compound can oscillate as a laser.

[0069] The emission wavelength and color of the light-emitting material are appropriately selected depending on the oscillation wavelength of the laser oscillation material and the target emission wavelength and color. For example, the emission wavelength of the light-emitting material may be selected from the visible region, infrared region, or ultraviolet region.

[0070] Specific examples of luminescent materials include fluorene-based molecules, styrylbenzene-based molecules, carbazole-styrylbiphenyl compounds, TADF materials (thermally activated delayed fluorescent materials), star polymers, polyfluorenes, phenylene vinylene polymers, and ladder polymers described in Adv. Photonics Res. 2021, 2, 2000155, and examples of luminescent molecules described in CCS Chem. 2020, 2, 1203-1216. Here, "star polymer" refers to a polymer with three or more branched chains extending radially from a common center (e.g., a benzene core, a pyrene core, or a truxene core), and "ladder polymer" refers to a polymer in which monomer units are linked by two or more bonds. Representative examples of these compounds are listed below. Unless otherwise specified, n represents an integer between 2 and 20.

[0071]

[0072] These light-emitting materials may be used alone or in combination of two or more.

[0073] The triplet quencher can be a compound having a lower minimum excited triplet energy than the laser oscillation material, for example, a compound having a lower minimum excited triplet energy than the laser oscillation material and a higher minimum excited singlet energy than the laser oscillation material. The triplet quencher can be selected from organic compounds having an anthracene ring, for example. Specific examples of triplet quenchers having an anthracene ring are shown below.

[0074] The host material can be an organic compound having at least one of the excited singlet energy and the excited triplet energy higher than that of the laser material. This allows the singlet and triplet excitons generated in the laser material to be confined within the molecules of the laser material, thereby lowering the threshold current density for laser oscillation. Even if the singlet and triplet excitons cannot be sufficiently confined, they may contribute to lowering the threshold and improving the laser characteristics. Therefore, any host material that can achieve lowering the threshold and improving the laser characteristics can be used in this embodiment without any particular restrictions. In the organic electroluminescent device of this embodiment, light stimulated and emitted by the laser material propagates through the light-emitting layer due to the action of an optical resonator or the like and is emitted externally as light. The light emitted by the laser element may include spontaneously emitted light or amplified spontaneous emission light from the laser material, or may include light emitted from the host material, but for example, light is the main component. When a host material is used, the amount of the laser oscillation material contained in the light-emitting layer is, for example, 0.1 wt % or more, for example, 0.5 wt % or more, for example, 1 wt % or more, and for example, 99 wt % or less, for example, 90 wt % or less, for example, 70 wt % or less, for example, 50 wt % or less, 30 wt % or less, for example, 15 wt % or less. As the host material in the light-emitting layer, for example, an organic compound having hole transport ability and electron transport ability, preventing the emission wavelength from shifting to a longer wavelength, and having a high glass transition temperature can be used. As the host material, an appropriate host material can be selected from known host materials in consideration of the energy conditions and physical properties as described above.

[0075] Furthermore, materials (lasing materials and host materials) constituting the light-emitting layer can have hole mobility equivalent to or greater than that of BSBCz. This allows holes to efficiently accumulate near the interface between the light-emitting layer and the hole-blocking layer, allowing carrier recombination to occur more intensively in this region. Here, the hole mobility of the light-emitting layer can be greater than the electron mobility, for example, 10 times or more greater than the electron mobility. The thickness of the light-emitting layer can be, for example, 10 nm or more, for example, 30 nm or more, 50 nm or more, or 70 nm or more, or can be, for example, less than 200 nm, for example, 150 nm or less, or 100 nm or less. The thickness of the light-emitting layer can be selected, for example, from the range of 10 nm or more to less than 200 nm.

[0076] (Injection Layer) The injection layer is a layer provided between an electrode and an organic layer to reduce the driving voltage and improve the luminance of light emitted, and includes a hole injection layer and an electron injection layer, and may be provided between the anode and the light emitting layer or the hole transport layer, and between the cathode and the light emitting layer or the electron transport layer. The injection layer can be provided as needed.

[0077] (Hole Transport Layer) The hole transport layer is provided between the light-emitting layer and the hole injection section and has the function of transporting holes injected from the hole injection section to the light-emitting layer. The hole transport layer may be a hole injection transport layer having a hole injection function. Examples of materials for the hole transport layer include triazole derivatives, oxadiazole derivatives, imidazole derivatives, carbazole derivatives, indolocarbazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aniline-based copolymers, and conductive polymer oligomers, particularly thiophene oligomers. For example, the hole transport layer may be selected from the group of compounds consisting of porphyrin compounds, aromatic tertiary amine compounds, and styrylamine compounds, or may be selected from the group of compounds consisting of aromatic tertiary amine compounds.

[0078] (Electron Transport Layer) The electron transport layer is provided between the light-emitting layer and the electron injection portion and has the function of transporting electrons injected from the electron injection portion to the light-emitting layer. The electron transport layer may be an electron injection / transport layer having an electron injection function. Examples of materials for the electron transport layer include nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, and oxadiazole derivatives. Furthermore, among the above oxadiazole derivatives, thiadiazole derivatives in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, and quinoxaline derivatives having a quinoxaline ring known as an electron-withdrawing group can also be used as electron transport materials. Furthermore, polymer materials in which these materials are introduced into a polymer chain or in which these materials form the main chain of a polymer can also be used.

[0079] (Hole Blocking Layer) The hole blocking layer is provided adjacent to the light-emitting layer and has the function of preventing holes transported through the light-emitting layer toward the hole blocking layer from migrating toward the electron injection portion beyond the interface between the light-emitting layer and the hole blocking layer. For example, a material can be selected for the hole blocking layer such that the absolute value of the HOMO (Highest Occupied Molecular Orbital) energy of the hole blocking layer is greater than the absolute value of the HOMO energy of the light-emitting layer. The hole blocking layer can also be composed of a material with low hole mobility. The material for the hole blocking layer can be selected from a group of compounds having a nitrogen-containing aromatic heterocycle, for example, or can be selected from a group of compounds having a structure in which a nitrogen-containing aromatic heterocycle and an aromatic hydrocarbon ring are bonded. Examples of nitrogen-containing aromatic heterocycles include nitrogen-containing six-membered aromatic rings such as pyridine ring, pyrazine ring, pyrimidine ring, pyridazine ring, and triazine ring; azole rings such as imidazole ring, thiazole ring, and oxazole ring; and fused rings in which these nitrogen-containing six-membered aromatic rings or azole rings are fused with an aromatic hydrocarbon ring. The aromatic hydrocarbon ring may be a single ring or a fused ring in which two or more rings are fused. In the case of a fused ring, the number of fused rings may be selected from the range of, for example, 2 to 6. Specific examples of rings include a benzene ring and a naphthalene ring. The thickness of the hole-blocking layer is, for example, 1 nm or more, for example, 3 nm or more, and may be, for example, 5 nm or more, or 8 nm or more, or may be, for example, 80 nm or less, for example, 30 nm or less, or 15 nm or less.

[0080] (Electron Blocking Layer) The electron blocking layer is provided adjacent to the light-emitting layer and has the function of preventing electrons transported through the light-emitting layer toward the electron blocking layer from migrating toward the hole injection portion beyond the interface between the light-emitting layer and the electron blocking layer. A material can be selected for the electron blocking layer such that the absolute value of the energy of the LUMO (Lowest Unoccupied Molecular Orbital) of the electron blocking layer is smaller than the absolute value of the energy of the LUMO of the light-emitting layer. The electron blocking layer can also be composed of a material with low electron mobility. The thickness of the electron blocking layer is, for example, 1 nm or more, for example, 3 nm or more, and may be, for example, 5 nm or more or 8 nm or more, or may be, for example, 80 nm or less, for example, 30 nm or less or 15 nm or less.

[0081] When producing an organic electroluminescence element, the hole injection section, the electron injection section and each organic layer may be formed by any method without particular limitation, and may be produced by either a dry process or a wet process.

[0082] The organic electroluminescence device of the present invention may be an edge-emitting type in which light from the light-emitting layer propagates in the X direction and is emitted to the outside from an edge surface, or a surface-emitting type in which light from the light-emitting layer is bent in the Y direction and is emitted to the outside from the surface of the electron injection part or the surface on the hole injection part side. The edge-emitting type may be a top-emission type in which the surface from which light is emitted is the surface opposite to the substrate, a bottom-emission type in which the surface from which light is emitted is the surface on the substrate side, or a dual-emission type in which light is emitted from both the top side and the bottom side.

[0083] <Method for Controlling the Emission Wavelength of an Organic Electroluminescent Element> Next, a method for controlling the emission wavelength of an organic electroluminescent element of this embodiment will be described. The method of this embodiment controls the emission wavelength of an organic electroluminescent element, which includes a hole injection section that injects holes, an electron injection section that injects electrons, and an organic section disposed between the hole injection section and the electron injection section, wherein the organic section includes a light-emitting layer that recombines holes and electrons to emit light, and which has a refractive index periodic structure in which the refractive index changes periodically in a predetermined direction in a cross section (cross section in the XY directions) cut in a direction perpendicular to the thickness direction (Z direction) of the organic section, and the emission wavelength of the organic electroluminescent element is controlled by setting the period of the refractive index periodic structure. For an explanation of the "organic electroluminescent element" to be controlled in this embodiment, please refer to the description of the "organic electroluminescent element" above. In an organic electroluminescence element having a periodic refractive index structure in the organic part, light from the light-emitting layer is resonated and amplified by the periodic refractive index structure, propagates along the arrangement direction of the periodic structure, and then emitted to the outside, resulting in light emission. Here, the wavelength of the resonating light and the period of the periodic refractive index structure have a relationship expressed by the Bragg equation, and changing the period of the periodic refractive index structure also changes the emission wavelength of the element. Therefore, the emission wavelength of the organic electroluminescence element can be controlled by setting the period of the periodic refractive index structure.

[0084] In one aspect of this embodiment, the refractive index periodic structure of the organic electroluminescent element to be controlled has a periodic structure in which first regions and second regions are alternately arranged in a predetermined direction in an XY cross-sectional view. Here, the second regions are regions having a refractive index different from that of the first regions. For an explanation of "a periodic structure in which first regions and second regions are alternately arranged in a predetermined direction," please refer to the description in the "Organic electroluminescent element" section above. In one aspect of the present invention, the emission wavelength of this organic electroluminescent element is calculated by a calculation means based on the following Bragg equation, λ Ｂｒａｇｇ and Λ ｍ A step of determining the relationship between mλ and mλ (calculation step S1);Ｂｒａｇｇ = 2n ｅｆｆ Λ ｍ [where m is the diffraction order, λ Ｂｒａｇｇ is the Bragg wavelength, n ｅｆｆ is the effective refractive index of one of the first and second regions, Λ ｍ and n represent the pitch of the refractive index periodic structure. ｅｆｆ is the effective refractive index of the region having a higher refractive index out of the first region and the second region.] The pitch determining means calculates λ Ｂｒａｇｇ and Λ ｍ In the relationship, λ Ｂｒａｇｇ is the desired emission wavelength, and this λ Ｂｒａｇｇ Λ corresponding to ｍ Select the selected Λ ｍ as the pitch of the refractive index periodic structure (pitch determination step S2). By designing an organic electroluminescence element using the pitch determined in the pitch determination step as the pitch of the refractive index periodic structure to be formed in the organic portion, an organic electroluminescence element that emits light at a target emission wavelength can be obtained. The target emission wavelength in this embodiment is not particularly limited, and may be in the visible region (380 to 780 nm), the infrared region, or the ultraviolet region.

[0085] <Program> The program of this embodiment is a program that causes a computer to function as a calculation means and a pitch determination means in order to implement the method described in the above-mentioned "Method for controlling the emission wavelength of an organic electroluminescence element." For an explanation of the steps performed by the calculation means and the steps performed by the pitch determination means, please refer to the above-mentioned "Method for controlling the emission wavelength of an organic electroluminescence element."

[0086] <Recording Medium> The program of this embodiment is a computer-readable recording medium on which the program described in the above description of "Program" is recorded. The recording medium may be any of a magnetic recording medium, an optical recording medium, and a semiconductor memory, and specific examples include a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM (Read Only Memory), a CD-R, a DVD-ROM, a magnetic tape, a non-volatile memory card, a ROM, an EEPROM, and a silicon disk.

[0087] In the organic electroluminescence element of this embodiment, the refractive index periodic structure of the organic portion functions as an optical resonator, so there is no need to provide an optical resonator as a separate member.

[0088] 1, 15, 21 Hole injection part 2, 16 First organic layer 2C Cross section of first organic layer (first region) 3, 17 Second organic layer (light emitting layer) 3C Cross section of second organic layer (second region) 4, 18, 23 Electron injection part 5 Convex body 6C, 8C, 11C, 13C, 171C First region 7C, 9C, 12C, 14C, 172C Second region 22 Organic part 24 Electrode layer 241 First electrode region 242 Second electrode region 241C End surface of first electrode region 242C End surface of second electrode region 25 Organic layer 251 First organic region 252 Second organic region 251C End surface of first organic region 252C End face of second organic region

[0089] <Another Invention> Below, a technical concept will be described from a different perspective from the above invention. The technical concept described below relates to a method for controlling the light extraction characteristics of an organic electroluminescence element, an organic electroluminescence element with controlled light extraction characteristics, and a display device in which pixels are composed of the organic electroluminescence elements. The technical concept described below will be referred to as "the present technology."

[0090] [Background Art] Organic electroluminescence elements (organic EL elements) have been used, for example, as organic solid-state semiconductor lasers. Compared to inorganic semiconductor lasers, organic solid-state semiconductor lasers have a wider wavelength tunability, are easier to provide flexibility, and can be manufactured at low cost. Therefore, they are expected to be applied to a variety of fields, such as laser light sources that oscillate at specific wavelengths and display devices having multiple pixels with different emission wavelengths. Research and development toward practical application is actively underway. For example, WO 2018 / 147470 describes the fabrication of an organic solid-state semiconductor laser using BSBCz (4-4'-bis[(N-carbazole)styryl]biphenyl) as a laser oscillation material, and the confirmation of laser oscillation. As shown in FIG. 35 , the organic solid-state semiconductor laser fabricated here comprises an ITO cathode 101, an emitting layer 102 containing BSBCz, and a MoO ３ The anode 103 is formed by laminating a layer / Ag layer / Al layer, and the light-emitting layer 102 is formed to a thickness of 210 nm.

[0091] [Problem] Organic electroluminescent elements and organic solid-state semiconductor lasers are expected to be applied to displays with pixel densities of 5,000 ppi or more and pixel pitches of 5 μm or less, for example, for AR (Augmented Reality) glasses and VR (Virtual Reality) glasses. In such displays, crosstalk between pixels can occur. Furthermore, increasing brightness is difficult. Therefore, precise control of light extraction characteristics, such as the light intensity distribution and light propagation direction at each pixel and crosstalk between pixels, is important. Furthermore, in organic EL display devices, optical components such as polarizers and retardation films are typically placed on the light extraction surface to prevent contrast degradation due to the incidence and reflection of external light. Therefore, it is desirable to control the polarization of light emitted from the organic electroluminescent element so that it can be efficiently extracted through these optical components. However, to date, no effective method for controlling these light extraction characteristics has been found. Therefore, in order to solve these problems of the prior art, the inventors conducted research with the aim of providing an organic electroluminescent element with improved light extraction characteristics.

[0092] [Means for Solving the Problems] As a result of intensive research to solve the above-mentioned problems, the inventors have found a configuration that effectively improves at least one of the polarization state of light generated in the light-emitting layer of an organic electroluminescent element, the lateral light intensity distribution and propagation direction of light extracted from the light extraction surface, and crosstalk between adjacent elements. The present technology has been proposed based on this finding and specifically has the following configuration. [1] A method for controlling the light extraction characteristics of an organic electroluminescent element comprising: a hole injection section that injects holes; an electron injection section that injects electrons; and a light-emitting layer that recombines holes and electrons to emit light, wherein light generated in the light-emitting layer propagates in the lateral direction of the light-emitting layer and is emitted from the light extraction surface, the method comprising providing a recombination concentration section along the lateral direction of the light-emitting layer.

[0093] Here, the recombination concentration region is a region where the recombination of holes and electrons occurs intensively, resulting in a high exciton density (exciton high density region). The position of the recombination concentration region can be determined, for example, by simulating the exciton density distribution.

[0094] [2] The method according to [1], wherein the light extraction characteristics are controlled by controlling at least one of the polarization state of light generated in the light-emitting layer, the lateral light intensity distribution and the direction of propagation of light extracted from the light extraction surface, and optical crosstalk and electrical crosstalk of the organic electroluminescent element. [3] The method according to [2], wherein the light intensity distribution in the depth direction is controlled in addition to the lateral direction when controlling the lateral light intensity distribution of the light. [4] The method according to [2] or [3], wherein at least one of the polarization state of light generated in the light-emitting layer, the lateral light intensity distribution and the direction of propagation of light extracted from the light extraction surface, and optical crosstalk and electrical crosstalk of the organic electroluminescent element is controlled, and the full width at half maximum (FWHM) of the peak of the light intensity distribution relative to the wavelength of the light extracted from the light extraction surface is reduced. In this specification, the "light intensity distribution relative to the wavelength of light" may be referred to as the "emission spectrum." [5] The method according to any one of [1] to [4], wherein the light extraction characteristics are controlled by providing a control member made of an insulating material having a lower refractive index than the light-emitting layer in contact with the light-emitting layer. [6] The method according to any one of [2] to [5], wherein the control of the light extraction characteristics is control of the polarization state of light generated in the light-emitting layer. [7] The method according to [6], wherein the control of the polarization state of light generated in the light-emitting layer is control of a striped diffraction grating in contact with the light-emitting layer. [8] The method according to any one of [2] to [7], wherein the control of the light extraction characteristics is control of at least one of the lateral light intensity distribution and the propagation direction from the lateral direction of light extracted from the light extraction surface, and optical crosstalk and electrical crosstalk of the organic electroluminescent element.[9] The method according to [8], wherein at least one control member selected from a striped diffraction grating, a circular diffraction grating, a partition made of an insulating material having a refractive index lower than that of the light-emitting layer, and a photonic crystal material is provided in contact with the light-emitting layer to control at least one of the lateral light intensity distribution and the lateral propagation direction of light extracted from the light extraction surface, and optical crosstalk and electrical crosstalk of the organic electroluminescent element.

[10] The method according to any one of [1] to [9], wherein when the side of the light-emitting layer that becomes the exciton high-density region is the electron injection section side, a hole blocking layer is provided between the light-emitting layer and the electron injection section and adjacent to the light-emitting layer, and when the side of the light-emitting layer that becomes the exciton high-density region is the hole injection section side, an electron blocking layer is provided between the light-emitting layer and the hole injection section and adjacent to the light-emitting layer.

[11] The method according to any one of [1] to

[10] , wherein a low-refractive index layer having a refractive index lower than that of the light-emitting layer is provided between the light-emitting layer and the hole injection section and between the light-emitting layer and the electron injection section.

[12] The method according to any one of [1] to

[11] , wherein the position of the exciton high-density region of the light-emitting layer is determined by simulating the exciton density distribution in the light-emitting layer.

[13] The method according to any one of [8] to

[12] , wherein the side of the light-emitting layer that becomes the exciton high-density region is the electron injection section side, and a hole blocking layer is provided between the light-emitting layer and the electron injection section and adjacent to the light-emitting layer.

[14] The method according to

[13] , wherein the absolute value of the HOMO energy of the hole blocking layer is made larger (e.g., 0.1 eV or more, e.g., 0.2 eV or more, e.g., 0.4 eV or more) than the absolute value of the HOMO energy of the light-emitting layer.

[15] The method according to

[13] or

[14] , wherein the hole mobility of the hole blocking layer is reduced.

[16] The method according to any one of

[13] to

[15] , wherein one or more layers (e.g., an electron transport layer) are provided between the hole blocking layer and the electron injection part.

[17] The method according to

[16] , wherein the electron mobility of the electron transport layer is reduced.

[18] The method according to

[16] or

[17] , characterized in that the absolute value of the HOMO energy of the electron transport layer is made larger by 0.1 eV or more (e.g., larger by 0.2 eV or more) than the absolute value of the HOMO energy of the light-emitting layer.

[19] The method according to any one of

[13] to

[18] , characterized in that the total thickness of the layers between the light-emitting layer and the electron injection section is increased.

[20] The method according to any one of

[13] to

[19] , characterized in that the total thickness of one or more layers between the light-emitting layer and the electron injection section is made larger by two or more times (e.g., 2.5 or more times, e.g., 3 or more times) the total thickness of one or more layers between the light-emitting layer and the hole injection section.

[21] The method according to any one of

[13] to

[20] , characterized in that the refractive index of the layer between the light-emitting layer and the electron injection section is reduced.

[22] The method according to any one of

[13] to

[21] , characterized in that the refractive index of the light-emitting layer is increased.

[23] The method according to any one of

[13] to

[22] , characterized in that the hole mobility of the light-emitting layer is increased.

[24] The method according to any one of

[13] to

[23] , characterized in that the light-emitting layer is thinned.

[25] The method according to any one of

[13] to

[24] , characterized in that the hole mobility of a layer between the hole injection section and the light-emitting layer is increased.

[26] The method according to any one of

[10] to

[12] , wherein the side of the light-emitting layer that becomes the exciton high density region is the hole injection section side, and an electron blocking layer is provided between the light-emitting layer and the hole injection section and adjacent to the light-emitting layer.

[27] The method according to

[26] , characterized in that the absolute value of the LUMO energy of the electron blocking layer is smaller by 0.1 eV or more (e.g., 0.2 eV or more, e.g., 0.4 eV or more) than the absolute value of the HOMO energy of the light-emitting layer.

[28] The method according to

[26] or

[27] , characterized in that the electron mobility of the electron blocking layer is reduced.

[29] The method according to any one of

[26] to

[28] , wherein a hole transport layer is provided between the electron blocking layer and the hole injection part.

[30] The method according to any one of

[26] to

[29] , wherein the hole mobility of the hole transport layer is reduced.

[31] The method according to any one of

[26] to

[30] , characterized in that the absolute value of the LUMO energy of the hole transport layer is made smaller by 0.1 eV or more (e.g., smaller by 0.2 eV or more) than the absolute value of the LUMO energy of the light-emitting layer.

[32] The method according to any one of

[26] to

[31] , characterized in that the total thickness of the layers between the light-emitting layer and the hole injection section is increased.

[33] The method according to any one of

[26] to

[32] , characterized in that the total thickness of one or more layers between the light-emitting layer and the hole injection section is made larger by two or more times (e.g., 2.5 or more times, e.g., 3 or more times) the total thickness of one or more layers between the light-emitting layer and the electron injection section.

[34] The method according to any one of

[26] to

[33] , characterized in that the refractive index of the layer between the light-emitting layer and the hole injection section is reduced.

[35] The method according to any one of

[26] to

[34] , characterized in that the refractive index of the light-emitting layer is increased.

[36] The method according to any one of

[26] to

[35] , characterized in that the electron mobility of the light-emitting layer is increased.

[37] The method according to any one of

[26] to

[36] , characterized in that the light-emitting layer is thinned.

[38] The method according to any one of

[26] to

[37] , characterized in that the electron mobility of a layer between the electron injection section and the light-emitting layer is increased.

[39] The method according to any one of [1] to

[38] , characterized in that the full width at half maximum (FWHM) of the emission wavelength peak is 10 nm or less (e.g., 7 nm or less, e.g., 5 nm or less, e.g., 4 nm or less, e.g., 3 nm or less, e.g., 2 nm or less, e.g., 1 nm or less).

[40] The method according to any one of [1] to

[39] , wherein the electron injection section has a structure in which a dielectric, a metal, and a dielectric are sequentially stacked (DMD structure).

[41] The method according to any one of [1] to

[40] , characterized in that it is a method for designing an organic electroluminescence device.

[42] The method according to any one of [1] to

[41] , wherein the organic electroluminescent element further comprises an optical resonator that propagates emitted light within a light-emitting layer, and the organic electroluminescent element oscillates laser light.However, when the organic electroluminescence element has the striped diffraction grating or the circular diffraction grating, the diffraction grating may function both as a light extraction characteristic control member and as an optical resonator. [42-2] The method according to

[42] , wherein the light extracted from the light extraction surface is laser light.

[43] The method according to [42-2], wherein the optical resonator has a diffraction grating.

[44] The method according to

[43] , wherein the hole blocking layer or the electron blocking layer is formed along a flat interface of the light-emitting layer.

[45] The method according to

[43] or

[44] , wherein the diffraction grating is disposed between the exciton high density region and the hole injection part, or between the exciton high density region and the electron injection part.

[46] The method according to

[45] , wherein when a diffraction grating is provided between the exciton high density region and the hole injection section, the hole blocking layer is provided between the light-emitting layer and the electron injection section and adjacent to the light-emitting layer; and when a diffraction grating is provided between the exciton high density region and the electron injection section, the electron blocking layer is provided between the light-emitting layer and the hole injection section and adjacent to the light-emitting layer.

[47] The method according to any one of

[42] to

[46] , characterized in that it is a method for designing an organic solid-state semiconductor laser.

[48] A device having an organic electroluminescence element with controlled light extraction characteristics, manufactured by carrying out the method according to any one of [1] to

[47] .

[49] A method for manufacturing a device having an organic electroluminescence element with controlled light extraction characteristics, comprising a step of manufacturing an organic electroluminescence element by the method according to any one of [1] to

[47] .

[50] An organic electroluminescence element with controlled light extraction characteristics, manufactured by carrying out the method according to any one of [1] to

[47] .

[51] An organic solid-state semiconductor laser having controlled light extraction characteristics, produced by carrying out the method according to any one of

[42] to

[47] .

[52] An organic electroluminescence element comprising: a hole injection section for injecting holes; an electron injection section for injecting electrons; a light-emitting layer disposed between the hole injection section and the electron injection section and configured to recombine holes and electrons to emit light; and an optical resonator for propagating the emitted light within the light-emitting layer, wherein light is extracted from a light extraction surface, the organic electroluminescence element further comprising: a hole blocking layer adjacent to the light-emitting layer on the electron injection section side of the light-emitting layer; or an electron blocking layer adjacent to the light-emitting layer on the hole injection section side of the light-emitting layer; and a control member for controlling light extraction characteristics at the light extraction surface.

[53] The organic electroluminescence element according to

[52] , wherein the control of the light extraction characteristics is control of at least one of the polarization state of light generated in the light-emitting layer, the lateral light intensity distribution and the lateral propagation direction of light extracted from the light extraction surface, and optical crosstalk and electrical crosstalk of the organic electroluminescence element.

[54] The organic electroluminescent element according to

[52] or

[53] , wherein the control member is made of an insulating material having a lower refractive index than the light-emitting layer and is provided in contact with the light-emitting layer.

[55] The organic electroluminescent element according to any one of

[52] to

[54] , wherein the control member has a striped diffraction grating or a circular diffraction grating, and the striped diffraction grating and the circular diffraction grating also function as the optical resonator.

[56] The organic electroluminescent element according to any one of

[52] to

[55] , wherein the control member has a striped diffraction grating, and the diffraction grating has ridges arranged side by side in the lateral direction of the light-emitting layer.

[57] The organic electroluminescent element according to

[56] , wherein the striped diffraction grating is a first-order diffraction grating.

[58] The organic electroluminescent element according to

[56] , wherein the striped diffraction grating includes a second-order diffraction grating.

[59] The organic electroluminescent element according to

[58] , wherein the striped diffraction grating is a second-order diffraction grating.

[60] The organic electroluminescent element according to any one of

[52] to

[55] , having a circular diffraction grating including a second-order diffraction grating as the control member.

[61] The organic electroluminescent element according to

[60] , wherein the circular diffraction grating is a second-order diffraction grating.

[62] The organic electroluminescent element according to

[60] , wherein the circular diffraction grating is a mixed diffraction grating including a first-order diffraction grating and a second-order diffraction grating.

[63] The organic electroluminescent element according to any one of

[52] to

[52] , wherein the control member includes a partition wall surrounding the end face of the light-emitting layer, the partition wall being made of an insulating material having a refractive index lower than that of the light-emitting layer.

[64] The organic electroluminescent element according to any one of

[52] to

[62] , wherein the control member includes a photonic crystal material surrounding the light-emitting layer.

[65] The organic electroluminescent element according to any one of

[52] to

[64] , wherein the control member includes a hole-blocking layer adjacent to the light-emitting layer on the electron injection section side of the light-emitting layer.

[66] The organic electroluminescent device according to

[65] , wherein the absolute value of the HOMO (Highest Occupied Molecular Orbital) energy of the hole blocking layer is 0.1 eV or more greater than the absolute value of the HOMO energy of the light-emitting layer.

[67] The organic electroluminescent device according to

[65] , wherein the absolute value of the HOMO energy of the hole blocking layer is 0.2 eV or more greater than the absolute value of the HOMO energy of the light-emitting layer.

[68] The organic electroluminescent device according to

[65] , wherein the absolute value of the HOMO energy of the hole blocking layer is 0.4 eV or more greater than the absolute value of the HOMO energy of the light-emitting layer.

[69] The organic electroluminescent device according to any one of

[65] to

[68] , wherein the hole blocking layer is made of a material having low hole mobility.

[70] The organic electroluminescence device according to any one of

[65] to

[68] , wherein the hole blocking layer is made of a material having a hole mobility equal to or less than that of TPBi ([1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene]) (for example, equal to or less than that of T2T (2,4,6-tris([1,1'-biphenyl]-3-yl))-1,3,5-triazine)).

[71] The organic electroluminescence device according to any one of

[65] to

[70] , wherein the hole blocking layer has a thickness of 1 nm or more (for example, 3 nm or more, for example, 5 nm or more, for example, 8 nm or more, and for example, 80 nm or less, for example, 30 nm or less, for example, 15 nm or less).

[72] The organic electroluminescence device according to any one of

[65] to

[71] , further comprising an electron transport layer between the hole blocking layer and the electron injection part.

[73] The organic electroluminescence device according to

[72] , wherein the thickness of the electron transport layer is 10 nm or more (e.g., 20 nm or more, e.g., 40 nm or more, e.g., 60 nm or more, and e.g., 100 nm or less, e.g., 80 nm or less).

[74] The organic electroluminescence device according to

[72] or

[73] , wherein the electron transport layer is made of a material having an electron mobility equal to or less than that of TPBi ([1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene]).

[75] The organic electroluminescence device according to any one of

[72] to

[74] , wherein the absolute value of the HOMO energy of the electron transport layer is 0.1 eV or more (e.g., 0.2 eV or more) greater than the absolute value of the HOMO energy of the light-emitting layer.

[76] The organic electroluminescence element according to any one of

[65] to

[75] , wherein the total thickness of the one or more layers provided between the light-emitting layer and the electron injection part is at least twice (e.g., at least 2.5 times, e.g., at least 3 times) larger than the total thickness of the one or more layers provided between the light-emitting layer and the hole injection part.

[77] The organic electroluminescence device according to any one of

[65] to

[76] , characterized in that the light-emitting layer is composed of a material having a hole mobility equal to or greater than that of BSBCz (4-4'-bis[(N-carbazole)styryl]biphenyl).

[78] The organic electroluminescence device according to any one of

[65] to

[77] , characterized in that the light-emitting layer contains a laser oscillation material and a dopant material.

[79] The organic electroluminescence device according to

[78] , characterized in that the dopant material contains a light-emitting material.

[80] The organic electroluminescence device according to

[79] , characterized in that the light-emitting material is a compound selected from the group consisting of fluorene-based molecules, styrylbenzene-based molecules, carbazole-styryl 6-biphenyl compounds, TADF materials (thermally activated delayed fluorescence materials), star polymers, polyfluorenes, phenylene vinylene polymers, and ladder polymers.

[81] The organic electroluminescence device according to any one of

[78] to

[80] , wherein the dopant material contains a triplet quencher.

[82] The organic electroluminescence device according to

[81] , wherein the triplet quencher is a compound containing an anthracene ring.

[83] The organic electroluminescence device according to

[82] , wherein the compound containing an anthracene ring is the following compound:

[84] The organic electroluminescence device according to any one of

[65] to

[83] , characterized in that a layer composed of a material having a hole mobility equal to or greater than that of HATCN ([dipyrazino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile]) is disposed between the hole injection part and the light-emitting layer.

[85] The organic electroluminescence device according to any one of

[52] to

[64] , characterized in that an electron blocking layer is disposed adjacent to the light-emitting layer on the hole injection part side of the light-emitting layer.

[86] The organic electroluminescence device according to

[85] , characterized in that the absolute value of the energy of the lowest unoccupied molecular orbital (LUMO) of the electron blocking layer is smaller by 0.1 eV or more than the absolute value of the energy of the LUMO of the light-emitting layer.

[87] The organic electroluminescent device according to

[80] , wherein the absolute value of the LUMO energy of the electron blocking layer is smaller by 0.2 eV or more than the absolute value of the LUMO energy of the light-emitting layer.

[88] The organic electroluminescent device according to

[85] , wherein the absolute value of the LUMO energy of the electron blocking layer is smaller by 0.4 eV or more than the absolute value of the LUMO energy of the light-emitting layer.

[89] The organic electroluminescent device according to any one of

[85] to

[88] , wherein the electron blocking layer is made of a material having low electron mobility.

[90] The organic electroluminescent device according to any one of

[85] to

[89] , wherein the electron blocking layer is made of a material having low electron mobility.

[91] The organic electroluminescence device according to any one of

[85] to

[90] , wherein the thickness of the electron blocking layer is 1 nm or more (for example, 3 nm or more, for example, 5 nm or more, for example, 8 nm or more, and for example, 80 nm or less, for example, 30 nm or less, for example, 15 nm or less).

[92] The organic electroluminescence device according to any one of

[85] to

[91] , further comprising a hole transport layer between the electron blocking layer and the hole injection part.

[93] The organic electroluminescence device according to

[92] , wherein the thickness of the hole transport layer is 10 nm or more (e.g., 20 nm or more, e.g., 40 nm or more, e.g., 60 nm or more, and e.g., 100 nm or less, e.g., 80 nm or less).

[94] The organic electroluminescence device according to

[92] or

[93] , wherein the hole transport layer is made of a material having a hole mobility equal to or less than that of HATCN ([dipyrazino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile]).

[95] The organic electroluminescence device according to any one of

[92] to

[94] , wherein the absolute value of the LUMO energy of the hole transport layer is smaller by 0.1 eV or more (e.g., smaller by 0.2 eV or more) than the absolute value of the LUMO energy of the light-emitting layer.

[96] The organic electroluminescent device according to any one of

[84] to

[95] , wherein the total thickness of one or more layers provided between the light-emitting layer and the hole injection section is at least twice (e.g., at least 2.5 times, e.g., at least 3 times) greater than the total thickness of one or more layers provided between the light-emitting layer and the electron injection section.

[97] The organic electroluminescent device according to any one of

[52] to

[96] , wherein the refractive index of the layer provided between the light-emitting layer and the electron injection section is smaller than the refractive index of the light-emitting layer.

[98] The organic electroluminescent device according to any one of

[52] to

[97] , wherein the refractive index of the layer provided between the light-emitting layer and the hole injection section is smaller than the refractive index of the light-emitting layer.

[99] The organic electroluminescent device according to any one of

[51] to

[98] , wherein the thickness of the light-emitting layer is 10 nm or more and less than 200 nm.

[100] The organic electroluminescent element according to any one of

[51] to

[99] , wherein the hole mobility of the light-emitting layer is 10 times or more larger than the electron mobility.

[101] The organic electroluminescent element according to any one of

[51] to

[100] , wherein the light-emitting layer is composed of only a light-emitting material.

[102] The organic electroluminescent device according to any one of

[51] to

[101] , wherein the light-emitting layer is a layer in which a light-emitting material is doped into a host material.

[103] The organic electroluminescent device according to any one of

[51] to

[102] , wherein the hole injection part is an electrode.

[104] The organic electroluminescent device according to any one of

[51] to

[103] , wherein at least one of the electron injection part and the hole injection part is an electrode having a visible light transmittance of 10% or more (e.g., 50% or more, e.g., 80% or more, e.g., 90% or more).

[105] The organic electroluminescent device according to any one of

[51] to

[104] , wherein the hole injection part is made of ITO (indium tin oxide).

[106] The organic electroluminescent device according to any one of

[51] to

[105] , wherein the electron injection part is an electrode.

[107] The organic electroluminescent device according to any one of

[51] to

[106] , wherein the electron injection part is a metal electrode.

[108] The organic electroluminescent device according to any one of

[51] to

[107] , wherein the electron injection part has a structure in which a dielectric, a metal and a dielectric are laminated in this order.

[109] The organic electroluminescent device according to

[108] , wherein the metal is silver (Ag).

[110] The dielectric is molybdenum trioxide (MoO. ３The organic electroluminescent device according to

[108] or

[104] , characterized in that the organic electroluminescent device is a surface-emitting type.

[111] The organic electroluminescent device according to any one of

[52] to

[110] , characterized in that the organic electroluminescent device is a surface-emitting type.

[112] The organic electroluminescent device according to any one of

[52] to

[107] , wherein light generated in the light-emitting layer propagates laterally across the light-emitting layer.

[113] The method according to

[112] , wherein low-refractive index layers having a refractive index lower than that of the light-emitting layer are provided between the light-emitting layer and the hole injection section, and between the light-emitting layer and the electron injection section.

[114] The organic electroluminescent device according to

[52] to

[113] , wherein the organic electroluminescent device is an organic solid-state semiconductor laser, and preferably the optical resonator has a diffraction grating.

[115] The organic electroluminescent device according to

[114] , wherein the hole blocking layer or the electron blocking layer is formed along a flat interface of the light-emitting layer.

[116] The organic electroluminescent device according to

[114] or

[115] , wherein a base end of the diffraction grating is disposed at the interface of the light-emitting layer on the hole injection section side or closer to the hole injection section than the interface, and the hole blocking layer is disposed between the light-emitting layer and the electron injection section and adjacent to the light-emitting layer.

[117] The organic electroluminescent device according to

[114] or

[115] , wherein a base end of the diffraction grating is disposed at the interface of the light-emitting layer on the electron injection section side or closer to the electron injection section than the interface, and the electron blocking layer is disposed between the light-emitting layer and the hole injection section and adjacent to the light-emitting layer.

[118] The organic electroluminescent device according to any one of

[52] to

[111] and

[114] to

[117] , wherein the organic electroluminescent device is a top-emission type.

[119] The organic electroluminescence element according to any one of

[52] to

[111] and

[114] to

[118] , which is a bottom-emission type.

[120] The organic electroluminescence element according to any one of

[52] to

[111] and

[114] to

[119] , which is a dual-emission type.

[121] The organic electroluminescent element according to any one of

[52] to

[117] , characterized in that it is an edge-emitting type.

[122] A display device having a plurality of pixels, wherein the plurality of pixels are organic electroluminescent elements whose light extraction characteristics have been controlled by the method according to any one of [1] to

[47] , or the organic electroluminescent element according to any one of

[51] to

[121] .

[123] A program for carrying out the method according to any one of [1] to

[47] .

[0095] The above-mentioned "DMD structure" is an abbreviation of dielectric-metal-dielectric structure. This can be adopted in the present technology as an electrode that utilizes interference of a laminated structure. As the DMD structure, MoO ３ / Ag / MoO3, ITO / Ag / ITO, ZnS / Ag / ZnS, ZnO / Ag / ZnO, InZnSnO / Ag / InZnSnO, ITO / Ag / WO ３ , ZnO / Ag / WO ３ , W.O. ３ / Ag / WO ３ In one aspect of the present technology, a DMD structure is employed as the electron injection unit. An element having the DMD structure can be manufactured, for example, through a process of forming the DMD structure on a silicon substrate.

[0096] By configuring the electron injection section using a material with high light transmittance, a top-emission organic electroluminescence element or an organic solid-state semiconductor laser can be provided. In one aspect of the present technology, the electron injection section is configured as a DMD structure or a thin Ag layer (for example, a thickness of 40 nm or less, for example, 5 to 30 nm, for example, 12 to 25 nm) with high light transmittance. Furthermore, by configuring the hole injection section using a material with high light transmittance, a bottom-emission organic electroluminescence element or an organic solid-state semiconductor laser can be provided. In one aspect of the present technology, the hole injection section is an ITO layer. Furthermore, by configuring both the electron injection section and the hole injection section using a material with high light transmittance, a dual-emission (see-through) organic electroluminescence element or an organic solid-state semiconductor laser can also be provided.

[0097] [Effects] According to the present technology, it is possible to realize an organic electroluminescence element in which at least one of the polarization state of light generated in the light-emitting layer, the lateral light intensity distribution and the direction of propagation of light extracted from the light extraction surface, and the optical crosstalk and electrical crosstalk of the organic electroluminescence element are improved.

[0098] [Detailed Description] The present technology will be described in detail below. The following description of the constituent elements may be based on representative embodiments or specific examples of the present technology, but the present technology is not limited to such embodiments or specific examples. In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits. The isotope of the hydrogen atoms present in the molecule of the compound used in the present technology is not particularly limited. For example, all hydrogen atoms in the molecule may be 1H, or some or all may be 2H (deuterium D). "Transparent" in the present technology refers to a visible light transmittance of 50% or more, for example, 80% or more, for example, 90% or more, or for example, 99% or more. Visible light transmittance can be measured using an ultraviolet-visible spectrophotometer. In the following description, when " / adjacent layer" and "adjacent layer / " are used, the "adjacent layer" refers to the layer adjacent to the layer described before or after the diagonal line.

[0099]

[0010] <Method for controlling light extraction characteristics of organic electroluminescence device> The method of the present technology is a method for controlling the light extraction characteristics of an organic electroluminescence device comprising: a hole injection section for injecting holes; an electron injection section for injecting electrons; and a light-emitting layer disposed between the hole injection section and the electron injection section and configured to recombine holes and electrons to emit light, wherein light generated in the light-emitting layer propagates laterally through the light-emitting layer and is extracted from a light-extraction surface, the method being characterized in that a recombination concentration section is provided along the lateral direction of the light-emitting layer. In one aspect of the present technology, when the side of the light-emitting layer that forms the exciton high-density region is the electron injection section side, a hole blocking layer is provided between the light-emitting layer and the electron injection section and adjacent to the light-emitting layer, and when the side of the light-emitting layer that forms the exciton high-density region is the hole injection section side, an electron blocking layer is provided between the light-emitting layer and the hole injection section and adjacent to the light-emitting layer, thereby providing the recombination concentration section along the lateral direction of the light-emitting layer. The "recombination concentration region" in this technology is a region where the recombination of holes and electrons occurs intensively, resulting in a high exciton density (exciton high density region). The position of the recombination concentration region can be determined, for example, by simulating the exciton density distribution.

[0100] (Organic Electroluminescence Element) The organic electroluminescence element targeted for control by this technology will be described. The organic electroluminescence element whose light extraction characteristics are controlled by this technology can be, for example, an organic electroluminescence element in which light generated in the light-emitting layer propagates laterally through the light-emitting layer. Here, the "lateral direction of the light-emitting layer" refers to the direction along the interface between the light-emitting layer and an adjacent layer (a direction perpendicular to the thickness direction). Light propagating laterally through the light-emitting layer may be emitted from an edge of the organic electroluminescence element, or may be bent vertically and emitted from the surface on the electron injection section or hole injection section side. In other words, the organic electroluminescence element targeted by this technology may be an edge-emitting type, a top-emission type, or a bottom-emission type, or may be a dual-emission type in which light is emitted from both the top and bottom sides. An organic electroluminescence element in which light propagates laterally through the light-emitting layer can be obtained by forming a refractive index guide or a gain guide within the element. Refractive index waveguides are formed by configuring at least one layer between the light-emitting layer and the hole injection section, and at least one layer between the light-emitting layer and the electron injection section, as low-refractive index layers with a refractive index lower than that of the light-emitting layer. For example, at least one of the electron transport layer and the hole blocking layer, and at least one of the electron blocking layer and the hole transport layer, can be configured as low-refractive index layers. In one aspect of the present technology, the layer adjacent to the electron injection section side of the light-emitting layer and the layer adjacent to the hole injection section side of the light-emitting layer are both low-refractive index layers with a refractive index lower than that of the light-emitting layer. These low-refractive index layers can function as cladding layers of the optical waveguide, and the region surrounded by the cladding layers can function as a core layer in which light is confined. Gain waveguides can also be formed by designing the device so that the gain is high in the central portion of the horizontal path. For an explanation of these waveguides, please refer to the descriptions of refractive index waveguides and gain waveguides in the <Organic Solid-State Semiconductor Laser> section. In such organic electroluminescent devices, light propagates horizontally, while the movement of holes traveling vertically is impeded (blocked) by the hole blocking layer.Alternatively, while light propagates in the horizontal direction, the movement of electrons proceeding in the vertical direction is prevented (blocked) by the electron blocking layer. Note that in the organic electroluminescent element targeted by this technology, it is sufficient that light propagates in the horizontal direction within the light-emitting layer, and the final light extraction direction can also be vertical.

[0101] In the present technology, the term "exciton high-density region" refers to a virtual cross-sectional region perpendicular to the thickness direction at the position where the exciton density is highest in the light-emitting layer when holes from the hole injection portion and electrons from the electron injection portion are injected into the light-emitting layer and carrier recombination occurs. The position of the exciton high-density region can be determined by simulating the exciton density distribution in the light-emitting layer. For example, in the simulation results shown in FIG. 34 obtained in the examples, the interface between the hole blocking layer HBL and the light-emitting layer EML, which corresponds to the peak of the exciton density distribution, corresponds to the "exciton high-density region." In addition, in the present technology, the "side that becomes the exciton high-density region" can be determined to be the hole injection portion side of the light-emitting layer when the exciton high-density region is located closer to the hole injection portion than the central plane in the thickness direction of the light-emitting layer, or the electron injection portion side of the light-emitting layer when the exciton high-density region is located closer to the electron injection portion than the central plane. Therefore, in the simulation results shown in FIG. 34, the electron injection portion side is determined to be the "side that becomes the exciton high-density region," and a hole blocking layer is provided between the light-emitting layer and the electron injection portion and adjacent to the light-emitting layer. Furthermore, if the simulation results show that the exciton density distribution peaks on the hole injection section side of the light-emitting layer, the hole injection section side can be determined to be the "side that becomes the exciton high density region," and an electron blocking layer can be provided between the light-emitting layer and the hole injection section and adjacent to the light-emitting layer.

[0102] The behavior of carriers in an organic electroluminescent device having a hole blocking layer or an electron blocking layer will be described with reference to FIGS. 30 and 31 . FIG. 30 shows an example of a device having a hole blocking layer between the light-emitting layer and the electron injection layer. In FIG. 30( a), 51 denotes a hole injection layer, 52 denotes a hole injection layer, 53 denotes a hole transport layer, 54 denotes a light-emitting layer, 55 denotes a hole blocking layer, 56 denotes an electron transport layer, 57 denotes an electron injection layer, and 58 denotes a diffraction grating that constitutes an optical resonator. FIG. 31 shows an example of a device having an electron blocking layer between the light-emitting layer and the hole injection layer. In FIG. 31, 61 denotes a hole injection layer, 62 denotes a hole transport layer, 63 denotes an electron blocking layer, 64 denotes a light-emitting layer, 65 denotes an electron transport layer, 66 denotes an electron injection layer, 67 denotes an electron injection layer, and 68 denotes a diffraction grating that constitutes an optical resonator. For an explanation of each layer and each part that constitutes the device, please refer to the description in the <Organic Solid-State Semiconductor Laser> section below. However, the organic electroluminescent element targeted by the present technology is not limited to the elements shown in Figures 30 and 31. When the side that becomes the exciton high density region is the electron injection section side, as shown in Figure 30(a), a hole blocking layer 55 can be provided at a position adjacent to the electron injection section 57 side of the light-emitting layer 54. As shown in Figure 30(b), in such an organic electroluminescent element, holes (+) that have moved through the light-emitting layer 54 are retained at the interface between the light-emitting layer 54 and the hole blocking layer 55, and carrier recombination occurs intensively in a narrow region near this interface, forming a carrier recombination region RZ where the exciton density is high. Ｈ is formed. This allows for effective control of light extraction characteristics and also reduces the peak full width at half maximum (FWHM) of the emission spectrum. On the other hand, when the side that becomes the exciton high density region is the hole injection section side, as shown in FIG. 31, an electron blocking layer 63 can be provided at a position adjacent to the hole injection section 61 side of the light emitting layer 64. In such an organic electroluminescence element, electrons (-) that have moved through the light emitting layer 64 are retained at the interface between the light emitting layer 64 and the electron blocking layer 63, and carrier recombination occurs intensively in a narrow region near this interface, forming a carrier recombination region RZ where the exciton density is high. ＨThis makes it possible to effectively control the light extraction characteristics and reduce the full width at half maximum (FWHM) of the emission spectrum.

[0103] In addition, in an embodiment in which a hole blocking layer is provided, an electron transport layer is provided between the electron injection section and the hole blocking layer, and the thickness of the electron transport layer is increased, thereby preventing light from the light-emitting layer from being absorbed by the electrode of the electron injection section. This improves the light extraction efficiency from the device. In addition, in an embodiment in which an electron blocking layer is provided, a hole transport layer is provided between the hole injection section and the electron blocking layer, and the thickness of the hole transport layer is increased, thereby preventing light from the light-emitting layer from being absorbed by the electrode of the hole injection section. This improves the light extraction efficiency from the device.

[0104] The organic electroluminescence element targeted by the present technology may be a normal organic electroluminescence element, or may be one (e.g., an organic solid-state semiconductor laser) that includes an optical resonator that propagates emitted light within the light-emitting layer and oscillates laser light. Here, when the optical resonator is a diffraction grating with periodic irregularities, the position of the recombination concentration area (exciton high density region) of the light-emitting layer can be near the interface (position along the interface) between the diffraction grating side and the adjacent layer on the opposite side. Furthermore, when the optical resonator is a diffraction grating with periodic irregularities, the position of the hole blocking layer or electron blocking layer can be adjacent to the flat interface of the light-emitting layer, or can be adjacent to the interface on the opposite side of the diffraction grating side of the light-emitting layer. This allows a carrier recombination region RZ to be formed in a narrow region along the interface between the light-emitting layer and the hole blocking layer or electron blocking layer. ＨSince a diffraction grating is formed, the light extraction characteristics can be effectively controlled, which is also advantageous for narrowing the peak width (FWHM) of the emission spectrum. Note that the diffraction grating here may be a circular diffraction grating or a striped diffraction grating used as a control member described later. That is, a circular diffraction grating or a striped diffraction grating may be used both as a control member and an optical resonator. In a preferred embodiment of the present technology, the organic electroluminescent device to be targeted has a diffraction grating between the exciton high density region of the light-emitting layer and the hole injection section, and the hole blocking layer can be provided between the light-emitting layer and the electron injection section and adjacent to the light-emitting layer. In a preferred embodiment of the present technology, the organic electroluminescent device to be targeted has a diffraction grating between the exciton high density region of the light-emitting layer and the electron injection section, and the electron blocking layer can be provided between the light-emitting layer and the hole injection section and adjacent to the light-emitting layer.

[0105] For descriptions of the hole injection section, electron injection section, and light-emitting layer constituting the organic electroluminescent element, the optical resonator provided as needed, and the hole blocking layer or electron blocking layer provided depending on the position of the exciton high-density region, please refer to the corresponding descriptions in the [First Embodiment] and [Second Embodiment] sections below. Furthermore, the organic electroluminescent element targeted by the present technology may have layers other than the hole injection section, electron injection section, light-emitting layer, hole blocking layer, and electron blocking layer. Examples of such layers include an electron transport layer, a hole transport layer, and a spacer layer, and the element may further have other layers or a substrate. For descriptions of these layers, please refer to the descriptions in the [First Embodiment] and [Second Embodiment] sections below. In this specification, organic electroluminescent elements having a substrate will be described with the substrate side as the "bottom side" and the side opposite the substrate as the "top side." The organic electroluminescence element may be the organic solid-state semiconductor laser of the first or second embodiment, or may be an organic electroluminescence element obtained by removing the optical resonator from these organic solid-state semiconductor lasers.

[0106] (Control of Light Extraction Characteristics) Next, the control of light extraction characteristics performed by the present technology will be described. The "light extraction characteristics" controlled by the present technology are characteristics when light from an organic electroluminescent element is extracted from a light extraction surface. The light extraction characteristics need only be controlled when light is extracted from the light extraction surface. For example, the light extraction characteristics may be controlled before the light passes through the light extraction surface. Here, the light extraction surface refers to the location of an organic electroluminescent element from which light is emitted, and includes, for example, the surface, the inside, a non-flat shape, and an organic electroluminescent element with a small light-emitting area such as a point light source. The light extraction surface may be, for example, the surface on the hole injection section side or the surface on the electron injection section side, the top surface or the bottom surface, or an end surface (edge) of the element. Furthermore, both the surface on the hole injection section side and the surface on the electron injection section side, or both the surface on the top side and the bottom side may be light extraction surfaces. The "light extraction characteristics" controlled by this technology include at least one of the polarization state of light generated in the light-emitting layer, the lateral light intensity distribution and propagation direction of light extracted from the light extraction surface (e.g., the propagation direction of light relative to the lateral direction), and the optical crosstalk and electrical crosstalk of the organic electroluminescent element. When controlling the lateral light intensity distribution of light, it is possible to control the light intensity distribution in the depth direction as well as the lateral direction. That is, it is also possible to control the in-plane light intensity distribution of light. Furthermore, the crosstalk controlled by this technology may occur within the element or outside the element. Examples of crosstalk occurring within an element include optical crosstalk caused by light propagating laterally through the light-emitting layer leaking into the light-emitting layer of an adjacent element, and electrical leakage (electrical crosstalk) between elements that occurs when adjacent elements share a hole transport layer or electron transport layer. For example, when adjacent elements constitute pixels of different colors, the optical crosstalk may manifest as, for example, color bleeding into adjacent pixels or a decrease in color purity in low-brightness areas.Examples of crosstalk that occurs outside the element include electrical crosstalk, which occurs when wiring coupling in the drive circuit affects the drive voltage and current, causing changes in gradation, and optical crosstalk, which occurs when light emitted from the element that makes up a pixel spreads in a fan shape and enters the color filter of an adjacent pixel, resulting in a decrease in color purity and brightness.

[0107] Furthermore, when controlling the "light extraction characteristics," it is also possible to control the propagation direction of light (for example, within the element) before it is extracted from the light extraction surface. The horizontal propagation direction of light within the element can be controlled to a direction perpendicular to the horizontal direction (vertical direction), for example, when the thickness of the electron transport layer or hole transport layer is increased. This allows light generated in the light-emitting layer to be efficiently extracted from the surface of the element, even when the thickness of the electron transport layer or hole transport layer is increased.

[0108] The control of the "light extraction characteristics" in this technology is, for example, at least one of (a) converting the polarization state of light generated in the light-emitting layer from random polarization to specific polarization, (b) sharpening the peak of the light intensity distribution in the horizontal direction on the light extraction surface, (b') sharpening the peak of the light intensity distribution in the horizontal and depth directions on the light extraction surface, (c) aligning the traveling direction of light emitted from the light extraction surface in a specific direction, such as a direction perpendicular to the horizontal direction (vertical direction) or a direction parallel to the horizontal direction, (d) suppressing or preventing optical crosstalk, and (e) suppressing or preventing electrical crosstalk. Here, the recombination concentration portion (carrier recombination region RZ) along the horizontal direction of the light-emitting layer is ＨWhen a configuration in which a recombination concentration region is formed is adopted, excitons are generated locally in the recombination concentration region, forming an exciton high-density region, and light is emitted in this region. The light emitted in this manner has a smaller spread and a specific direction of travel than light emitted by carrier recombination dispersed throughout the entire light-emitting layer. Therefore, by providing a recombination concentration region along the lateral direction of the light-emitting layer, the peak of the lateral light intensity distribution of light extracted from the light extraction surface is sharpened, thereby suppressing or preventing optical crosstalk. Furthermore, by providing a control member (described later) in contact with the light-emitting layer, the above-mentioned light extraction characteristics can be effectively controlled. Below, a control member that can be used to control the light extraction characteristics will be described in detail.

[0109] (Control Member) The control member can be made of an insulating material with a lower refractive index than the light-emitting layer and can be provided so as to be in contact with the light-emitting layer. The insulating material used for the control member can be an inorganic insulating material or an organic insulating material. Examples of insulating materials that can be used for the control member include ceramics such as silicon dioxide, glass, and plastic. When the refractive index of the control member is lower than that of the light-emitting layer, light generated in the light-emitting layer is reflected at the interface between the light-emitting layer and the control member, thereby controlling the propagation direction, spatial light intensity distribution, and optical crosstalk between adjacent elements. Furthermore, when the control member is made of an insulating material, electrical crosstalk between adjacent elements can be suppressed or prevented. These low-refractive-index insulating materials can be used as materials for the circular diffraction gratings, striped diffraction gratings, and partition walls described below.

[0110] A circular diffraction grating can be given as an example of a control member that controls at least one of the light intensity distribution in the lateral and depth directions of light extracted from the light extraction surface, the propagation direction of light from the lateral direction, and the optical crosstalk of the organic electroluminescent element. Figure 22 shows an example of a circular diffraction grating as a control member. In one aspect of the present technology, in Figure 22, 10 is a substrate with a hole injection portion, 11 is a clad layer (low refractive index layer), and 12 is a circular diffraction grating. At least a light-emitting layer, a hole blocking layer, and an electron injection portion can be provided on the circular diffraction grating 12. This allows a recombination concentration portion to be formed near the interface of the light-emitting layer with the hole blocking layer. In one aspect of the present technology, in Figure 22, 10 is a substrate with an electron injection portion, 11 is a clad layer (low refractive index layer), and 12 is a circular diffraction grating. At least a light-emitting layer, an electron blocking layer, and a hole injection portion can be provided on the circular diffraction grating 12. This allows a recombination concentration portion to be formed near the interface of the light-emitting layer with the electron blocking layer. The low refractive index layer 11 can be configured as a hole transport layer when the substrate 10 is a substrate with a hole injection section, and as an electron transport layer when the substrate 10 is a substrate with an electron injection section. The circular diffraction grating has concentric grating projections in a planar view, and can be provided so that at least a portion of the grating projections contact the light-emitting layer (so that they penetrate into the light-emitting layer). The grating projections of the circular diffraction grating are formed with their base end at the interface between an adjacent layer ("low refractive index layer 11" in FIG. 22) and the light-emitting layer, and the entire grating projections may contact the light-emitting layer. Alternatively, the grating projections may be formed with their base end at the interface between the electron injection section and the adjacent layer ("low refractive index layer 11" in FIG. 22) or the interface between layers disposed between the electron injection section and the light-emitting layer, and a portion of the grating projections may contact the light-emitting layer. The circular diffraction grating is designed to satisfy the following Bragg equation. Bragg equation: mλ Ｂｒａｇｇ = 2n ｅｆｆ Λ ｍ where m is the diffraction order, λ Ｂｒａｇｇ is the Bragg wavelength, n ｅｆｆ is the effective refractive index, Λ ｍis the period of the diffraction grating. The circular diffraction grating can be designed to include a second-order diffraction grating where m is 2. The circular diffraction grating may be a circular diffraction grating where m is 2, or may be a mixed-order diffraction grating that combines a first-order diffraction grating where m is 1 and a second-order diffraction grating where m is 2. In the case of a mixed-order diffraction grating, for example, the central region can be a second-order diffraction grating and its surrounding (peripheral region) can be a first-order diffraction grating. By using a circular diffraction grating including a second-order diffraction grating, light propagating laterally through the light-emitting layer can be confined to the center, bent vertically by the second-order diffraction grating, and emitted from the surface (light extraction surface). This allows a light intensity distribution with a sharp peak in the center to be obtained on the light extraction surface, effectively suppressing optical crosstalk between adjacent elements.

[0111] The dimensions of the diffraction grating as a control member (e.g., the height, width, and pitch of the grating projections, the diameter of the circular diffraction grating, etc.) can be appropriately designed according to the wavelength (emission color) of the light extracted from the light extraction surface. For example, in conventional organic displays that do not use a control member such as a diffraction grating, blue (B) pixels have a smaller amount of light emission per unit area than other pixels and a shorter lifespan. Therefore, for blue (B) pixels, the lifespan is secured by reducing the applied current per unit area, or the pixel area is increased to increase the amount of light emission. Therefore, in conventional organic displays, the blue (B) pixel area must be relatively large, which limits the improvement of pixel density. In contrast, in one aspect of this embodiment using a diffraction grating as a control member, for example, the grating pitch of the blue (B) pixel can be designed to be narrower than that of the red (R) and green (G) pixels so as to satisfy the Bragg equation, thereby increasing the amount of light emission per unit area. Therefore, a sufficient amount of light emission can be secured, and the blue (B) pixel area can be designed to be smaller.

[0112] Figure 23 shows the simulation results of the optical resonance mode of an element using a circular diffraction grating. Figure 23(a) shows the simulation results for the top surface of an element using a 10 μm diameter circular diffraction grating, and Figure 23(b) shows the simulation results for the cross section of an element using a 3.3 μm diameter circular diffraction grating. Table 1 also shows the results of calculations of the optical confinement ratio for elements using a second-order circular diffraction grating or a mixed-order circular diffraction grating. The calculation results shown in Table 1 show that by using a circular diffraction grating, light is confined to the center, resulting in a light intensity distribution with a sharp peak at the center.

[0113]

[0114] The circular diffraction grating used in the present technology may have the functions of both a control element and a distributed feedback (DFB) optical resonator. In one aspect of the present technology, the target to be controlled is an organic solid-state semiconductor laser, and a circular diffraction grating serving as both a control element and a DFB optical resonator is provided in contact with the light-emitting layer.

[0115] An example of a control member that controls at least one of the lateral light intensity distribution and the lateral propagation direction of light extracted from the light extraction surface, and the optical crosstalk of the organic electroluminescent element, is a diffraction grating having a plurality of convex portions arranged in a stripe pattern. In one aspect of the present technology, the stripe-shaped diffraction grating serving as the control member has the longitudinal direction of each convex portion perpendicular to the lateral direction of the light-emitting layer, and the plurality of convex portions arranged side by side in the lateral direction. The stripe-shaped diffraction grating is designed to satisfy the above Bragg equation. The stripe-shaped diffraction grating may be a first-order diffraction grating where m is 1, a second-order diffraction grating where m is 2, or a third-order diffraction grating where m is 3, or may be a higher-order diffraction grating. It may also be a mixed-order diffraction grating that combines diffraction gratings of different orders. The stripe-shaped diffraction grating may function as both a control member and a DFB optical resonator. In one aspect of the present technology, the target to be controlled is an organic solid-state semiconductor laser, and a stripe-shaped diffraction grating that serves as both a control member and a DFB optical resonator is provided in contact with the light-emitting layer.

[0116] Control of light extraction characteristics using a striped diffraction grating will be described with reference to FIGS. 24 to 28 , using an organic solid-state semiconductor laser as an example. FIGS. 24 and 27 are schematic perspective views showing a portion of a display device in which three organic solid-state semiconductor lasers constituting red (R), green (G), and blue (B) pixels are arranged side by side. FIG. 24 shows an edge-emitting display device, and FIG. 27 shows a top-emission display device. In one aspect of the present technology, in FIGS. 24 and 27 , 21 and 31 are hole injection sections, 22R, 22G, 22B, 32R, 32G, and 32B are diffraction gratings (DFB optical resonators), 23 and 33 are hole transport layers, 24 and 34 are light-emitting layers, 25 and 35 are stacked structures of a hole blocking layer / electron transport layer, and 26 and 27 are electron injection sections. 24 and 27, 21 and 31 are electron injection sections, 22R, 22G, 22B, 32R, 32G, and 32B are diffraction gratings (DFB optical resonators), 23 and 33 are electron transport layers, 24 and 34 are light-emitting layers, 25 and 35 are stacked structures of electron blocking layer / hole transport layer, and 26 and 36 are hole injection sections. Here, the hole transport layer 23, the electron transport layer 23, and the hole blocking layer and electron blocking layer of the stacked structure 25 can be made of a material with a lower refractive index than the light-emitting layer and function as cladding layers. In the edge-emitting display device shown in FIG. 24, the DFB optical resonators 22R, 22G, and 22B are first-order diffraction gratings, and are each designed to satisfy the following formula: λ Ｂｒａｇｇ (R) = 2n ｅｆｆ Λ Ｒ１ λ Ｂｒａｇｇ (R) = 2n ｅｆｆ Λ Ｇ１ λ Ｂｒａｇｇ (B) = 2n ｅｆｆ Λ Ｂ１ where λ Ｂｒａｇｇ (R) is a wavelength in the red region, which can be selected, for example, from the range of 625 to 780 nm, and λ Ｂｒａｇｇ (G) is a wavelength in the green region, which can be selected, for example, from the range of 500 to 565 nm, and λ Ｂｒａｇｇ (B) is a wavelength in the blue region, which can be selected, for example, from the range of 450 to 485 nm. Ｒ１is the period of the DFB optical resonator 22R, and Λ Ｇ１ is the period of the DFB optical resonator 22G, and Λ Ｂ１ is the period of the DFB optical resonator 22B. ｅｆｆ is the effective refractive index. As shown in Figure 25, in the organic solid-state semiconductor laser targeted by this technology, the light generated in the recombination concentrated portion RZ of the light-emitting layer propagates in the lateral direction. At this time, if a DFB optical resonator 22 (22B, 22G, 22R) which is a first-order diffraction grating is provided in the propagation path, the Bragg wavelength λ Ｂｒａｇｇ (R)λ Ｂｒａｇｇ (G), λ Ｂｒａｇｇ Only light with wavelengths matching (B) is amplified, and the light is confined to the center. Furthermore, as shown in FIG. 26, the vibration direction of the light's electric field is aligned parallel to the side surface of the lattice convex portion 22a, converting the light into linearly polarized light. Therefore, even if light generated in the light-emitting layer leaks into an adjacent pixel, only light of a specific wavelength is amplified by the DFB optical resonator in that pixel region, preventing color bleeding between pixels. Furthermore, the light amplified by each DFB optical resonator 22B, 22G, and 22R becomes linearly polarized light R, G, and B and is emitted from the center of the end surface (light extraction surface) of each pixel in a direction parallel to the horizontal direction. This effectively suppresses optical crosstalk that occurs within and outside the device, while efficiently obtaining linearly polarized light of multiple colors.

[0117] Furthermore, by linearly polarizing the light generated in the light-emitting layer, it is possible to eliminate the need for anti-reflection polarizers used in, for example, virtual reality (VR) glasses and augmented reality (AR) glasses. This avoids light loss in the polarizer, allowing the light extracted from the element to be used efficiently, thereby improving the contrast or reducing power consumption of the VR glasses or AR glasses. Note that, in one aspect of the present technology described here, the light generated in the light-emitting layer is linearly polarized, but the polarization control performed in this embodiment is not limited to linear polarization and also includes other polarization states such as circular polarization and reverse circular polarization.

[0118] In the top-emission display device shown in Fig. 27, the DFB optical resonators 32R, 32G, and 32B are second-order diffraction gratings, and are designed to satisfy the following equations: Ｂｒａｇｇ (R) = n ｅｆｆ Λ Ｒ２ λ Ｂｒａｇｇ (R) = n ｅｆｆ Λ Ｇ２ λ Ｂｒａｇｇ (B) = n ｅｆｆ Λ Ｂ２ where λ Ｂｒａｇｇ (R), λ Ｂｒａｇｇ (G), λ Ｂｒａｇｇ Regarding the explanation of (B), the λ of the DFB optical resonators 22R, 22G, and 22B Ｂｒａｇｇ (R), λ Ｂｒａｇｇ (G), λ Ｂｒａｇｇ See the description of (B). Ｒ２ is the period of the DFB optical resonator 32R, and Λ Ｇ２ is the period of the DFB optical resonator 32G, and Λ Ｂ２ is the period of the DFB optical resonator 32B. ｅｆｆ is the effective refractive index of the ridge portion. As shown in Figure 28, in the organic solid-state semiconductor laser targeted by this technology, the light generated in the recombination concentration portion RZ of the light-emitting layer propagates in the horizontal direction. At this time, if a DFB optical resonator 32 (32B, 32G, 32R) which is a second-order diffraction grating is provided in the propagation path, the propagation direction of the light is bent in the vertical direction due to the diffraction phenomenon, and the wavelength is changed to the Bragg wavelength λ Ｂｒａｇｇ (R), λ Ｂｒａｇｇ (G), λ ＢｒａｇｇOnly light that matches the wavelength (B) is amplified and confined to the center. Furthermore, as shown in FIG. 26, the vibration direction of the light's electric field is aligned parallel to the side surface of the ridge portion 22a, converting the light into linearly polarized light. Therefore, even if light generated in one light-emitting layer leaks into an adjacent light-emitting layer, the DFB diffraction grating in that region bends the light's propagation direction vertically, amplifying only light of a specific wavelength, preventing color bleeding between pixels. Furthermore, the light amplified by each DFB optical resonator becomes linearly polarized and exits vertically from the center of the top surface (light extraction surface) of each pixel, resulting in a light intensity distribution with a sharp peak in the center on the light extraction surface. This effectively suppresses optical crosstalk that occurs within and outside the device, while efficiently obtaining linearly polarized light of multiple colors.

[0119] An example of a control member for controlling crosstalk is a partition wall made of a low-refractive index insulating material formed to surround at least the end faces of the light-emitting layer. Control of light extraction characteristics using a partition wall will be described with reference to FIG. 29 , using an organic solid-state semiconductor laser as an example. FIG. 29 is a schematic cross-sectional view showing a portion of a top-emission display device in which three organic solid-state semiconductor lasers constituting red (R), green (G), and blue (B) pixels are arranged side by side. In one aspect of the present technology, in FIG. 29 , 40 denotes a substrate, 41 denotes a hole injection section, 42R, 42G, and 42B denote DFB optical resonators, 43 denotes a hole transport layer, 44 denotes a light-emitting layer, 45 denotes a stacked structure of a hole blocking layer / electron transport layer, 46 denotes an electron injection section, and 47 denotes a partition wall. 29 , 40 denotes a substrate, 41 denotes an electron injection portion, 42R, 42G, and 42B denote DFB optical resonators, 43 denotes an electron transport layer, 44 denotes a light-emitting layer, 45 denotes a stacked structure of an electron blocking layer / hole transport layer, 46 denotes a hole injection portion, and 47 denotes a partition wall. Here, in one aspect of the display device shown in Fig. 29 , the partition wall 47 is provided so as to surround each end face of the hole injection portion 41, the light-emitting layer 44, and the stacked structure 45 of the elements constituting each pixel of red R and green G, and in another aspect, the partition wall 47 is provided so as to surround each end face of the electron injection portion 41, the light-emitting layer 44, and the stacked structure 45 of the elements constituting each pixel of red R and green G, but it is sufficient that the partition wall is provided around at least the end face of the light-emitting layer among the end faces of the elements. That is, the partition wall may be provided so as to surround only the edge of the light-emitting layer, or so as to surround the edge of the light-emitting layer and the edge of the layer other than the light-emitting layer, or so as to surround the edge of the light-emitting layer, the edge of the layer other than the light-emitting layer, and the edge of the hole injection section or the electron injection section. In this organic solid-state semiconductor laser, since the edge of the light-emitting layer is surrounded by the partition wall, light generated in the light-emitting layer is reflected at the interface between the light-emitting layer and the partition wall, thereby suppressing or preventing optical crosstalk caused by leakage to the light-emitting layer of an adjacent element. Furthermore, since the edge of the hole injection section or the electron injection section, the hole transport layer, the hole blocking layer, the electron transport layer, and the electron blocking layer are also surrounded by the partition wall, they are electrically insulated from the adjacent element, thereby suppressing or preventing electrical crosstalk.

[0120] Photonic crystal materials can also be cited as an example of a control member that suppresses crosstalk between adjacent elements. By surrounding the light-emitting layer with a photonic crystal material whose stop band includes the wavelength of light generated in the light-emitting layer, the photonic crystal inhibits the propagation of light to the surroundings. This makes it possible to suppress or prevent optical crosstalk caused by light generated in the light-emitting layer leaking into the light-emitting layer of an adjacent element. The photonic crystal material can be appropriately selected from known materials and used.

[0121] The light extraction characteristics may be controlled using only one of these control members, or two or more of them in combination. For example, combinations of two or more may include a combination of a circular diffraction grating and a partition wall, a combination of a circular diffraction grating and a photonic crystal material, a combination of a striped diffraction grating and a partition wall, and a combination of a striped diffraction grating and a photonic crystal material. Furthermore, the control of the light extraction characteristics using these control members may be performed on organic electroluminescence elements other than organic solid-state semiconductor lasers.

[0122] <Organic Solid-State Semiconductor Laser> Next, an example in which the organic electroluminescence device of the present technology is used as an organic solid-state semiconductor laser will be described. The organic solid-state semiconductor laser of the present technology includes a hole injection section for injecting holes, an electron injection section for injecting electrons, a light-emitting layer that recombines holes and electrons to emit light, and an optical resonator for propagating the emitted light within the light-emitting layer. The organic solid-state semiconductor laser of the present technology is characterized in that it has a hole blocking layer adjacent to the light-emitting layer on the electron injection section side of the light-emitting layer, or an electron blocking layer adjacent to the light-emitting layer on the hole injection section side of the light-emitting layer, and a control member for controlling light extraction characteristics. In the following description, in the organic solid-state semiconductor laser of the present technology, an embodiment in which the hole blocking layer is adjacent to the light-emitting layer on the electron injection section side of the light-emitting layer is referred to as a "first embodiment," and an embodiment in which the electron blocking layer is adjacent to the light-emitting layer on the hole injection section side of the light-emitting layer is referred to as a "second embodiment." Below, the configurations of the first and second embodiments of the present technology will be described.

[0123] [First Embodiment] The organic solid-state semiconductor laser of the first embodiment includes at least a hole injection section, a light-emitting layer, a hole blocking layer, and an electron injection section stacked in this order, an optical resonator that propagates emitted light within the light-emitting layer, and a control member that controls light extraction characteristics. Here, the control member may serve both as the control member and the optical resonator. That is, in one aspect of the present technology, the organic solid-state semiconductor laser of the first embodiment includes at least a hole injection section, a light-emitting layer, a hole blocking layer, and an electron injection section stacked in this order, and includes a control member that serves both as the control member and the optical resonator. For a description of the control member, examples of control members that also serve as the optical resonator, and examples of other control members, please refer to the description in the (Control Member) section above. The organic solid-state semiconductor laser of the first embodiment may further include a spacer layer between the hole blocking layer and the electron injection section, or one or more layers between the light-emitting layer and the hole injection section. Here, the light-emitting layer, the hole blocking layer, the spacer layer, and one or more layers disposed between the light-emitting layer and the hole injection section may be organic layers. In this specification, the term "organic layer" refers to a layer containing 70% or more by weight of an organic compound, and the term "organic compound" refers to a compound containing one or more carbon atoms. The organic compound may be composed solely of atoms selected from the group consisting of carbon, hydrogen, oxygen, nitrogen, boron, and halogen atoms. A specific structural example of the first embodiment is shown in FIG. 30( a). In FIG. 30( a), 51 denotes a hole injection portion, 52 denotes a hole injection layer, 53 denotes a hole transport layer, 54 denotes a light-emitting layer, 55 denotes a hole blocking layer, 56 denotes an electron transport layer, 57 denotes an electron injection portion, and 58 denotes a diffraction grating that doubles as a control member and an optical resonator. Here, the electron transport layer 56 constitutes a spacer layer, and the hole injection layer 52 and the hole transport layer 53 correspond to the "one or more layers disposed between the light-emitting layer and the hole injection portion" described above. The diffraction grating may be a circular diffraction grating or a striped diffraction grating. For descriptions of these diffraction gratings, please refer to the corresponding descriptions in the (Control Member) section above.

[0124] The organic solid-state semiconductor laser of the first embodiment has a hole-blocking layer 55 provided adjacent to the light-emitting layer 54, thereby achieving high laser efficiency and laser emission with narrow peak widths in both the emission spectrum and the angular light intensity distribution. Furthermore, if necessary, a spacer layer 56 can be provided between the hole-blocking layer 55 and the electron injection section 57 to further improve the laser efficiency. The reason for this will be explained below with reference to FIGS. 30 and 35 . The conventional organic solid-state semiconductor laser shown in FIG. 35 has a light-emitting layer 102 with a thickness of approximately 200 nm made of a laser oscillation material and a diffraction grating 104 between the electron injection section 101 and the hole injection section 103, and has a homojunction structure in which carriers are injected from the electron injection section 101 and the hole injection section 103 into a single organic semiconductor layer (light-emitting layer 202). In such an organic solid-state semiconductor laser with a homojunction structure, when carriers (positive holes (+) and electrons (-)) are injected from the injection portions 101 and 103 into the light-emitting layer 102, the entire light-emitting layer 102 becomes a carrier recombination region RZ where the exciton density is low. Ｌ 30(b) , when carriers are injected from the injection sections 51 and 57, the holes (+) injected into the injection section 54 are transported toward the hole blocking layer 55 within the injection section 54. However, the interface 55s between the injection sections 51 and 57 acts as a barrier to prevent the holes (+) from moving toward the electron injection section 57. Therefore, holes (+) are accumulated near this interface 55s, and the accumulated holes and electrons (-) that have moved from the hole blocking layer 55 into the light emitting layer 54 cause concentrated carrier recombination, forming a carrier recombination region RZ with a high exciton density near this interface 55s. ＨAs a result, this region RZ Ｈ In addition, when the spacer layer 56 is disposed between the hole blocking layer 55 and the electron injection region 57, the carrier recombination region RZ Ｈ Since a space is created between the electron injection region 57 and the carrier recombination region RZ Ｈ This suppresses the loss of light generated by the laser due to the formation of surface plasmon polaritons on the electrode surface, as well as the loss of light due to absorption or scattering at the electrode. In this way, the organic solid-state semiconductor laser of the present technology concentrates the recombination region, which corresponds to the gain region, in a limited area within the light-emitting layer, and further provides a spacer layer as needed to distance it from the electrode, which causes loss, thereby maintaining the gain higher than the loss and achieving stable laser oscillation. With these features, the organic solid-state semiconductor laser of the present technology can further improve laser efficiency and monochromaticity, and also contributes to the realization of low-voltage operation.

[0125] Furthermore, in the organic solid-state semiconductor laser of the first embodiment, by having a diffraction grating that serves both as a control member and an optical resonator, a light intensity distribution having a sharp peak can be obtained on the light extraction surface, and when used to form pixels of a display device, optical crosstalk between adjacent pixels can be effectively suppressed or prevented. Furthermore, when a striped diffraction grating is used, light generated in the light-emitting layer can be converted into linearly polarized light and efficiently extracted from the light extraction surface.

[0126] Furthermore, the organic solid-state semiconductor laser of the first embodiment may further include a partition or a photonic crystal material as a control member. In this case, the optical resonator may also function as a control member, or may not function as a control member. By using a partition or a photonic crystal material as a control member, a light intensity distribution with a sharp peak can be obtained on the light extraction surface, and when used to form pixels of a display device, optical crosstalk between adjacent pixels can be effectively suppressed or prevented. Furthermore, when a partition is used, adjacent pixels are electrically insulated from each other, so electrical crosstalk can be effectively suppressed or prevented.

[0127] The following describes each component and each layer of the organic solid state semiconductor laser according to the first embodiment. For a description of the control component, please refer to the description in the (Control component) section above.

[0128] (Substrate) The organic solid-state semiconductor laser of the present technology may have each component and layer supported on a substrate. When the organic solid-state semiconductor laser is configured to extract laser light from the substrate side, a substrate that is translucent to the laser light is used as the substrate, and a transparent substrate made of glass, transparent plastic, quartz, or the like can be used. On the other hand, when the organic solid-state semiconductor laser is configured to extract laser light from the side opposite the substrate, the substrate is not particularly limited, and in addition to the transparent substrates described above, substrates made of silicon, paper, or cloth can also be used. The organic solid-state semiconductor laser of the first embodiment may have a hole injection section, a light-emitting layer, a hole blocking layer, and an electron injection section stacked in this order on a substrate, or may have an electron injection section, a hole blocking layer, a light-emitting layer, and a hole injection section stacked in this order on a substrate.

[0129] (Hole injection section) The hole injection section has the function of injecting holes. For example, when a light-emitting layer is provided adjacent to the hole injection section, holes are directly injected from the hole injection section into the light-emitting layer. Furthermore, when one or more layers are provided between the light-emitting layer and the hole injection section, holes are injected from the hole injection section into one of the one or more layers that is adjacent to the hole injection section, and the holes transported through the one or more layers are injected into the light-emitting layer.

[0130] In one aspect of the present technology, the hole injection portion of the first embodiment is an electrode, for example, a transparent electrode. The electrode (hereinafter referred to as "anode") that is the hole injection portion can be made of, for example, a metal, alloy, electrically conductive compound, or a mixture thereof having a large work function (4 eV or more). Specific examples of such electrode materials include metals such as Au, CuI, indium tin oxide (ITO), and SnO. ２ , ZnO, TiN, and other conductive transparent materials. ２ O ３ Materials capable of producing amorphous, transparent conductive films, such as ZnO, may also be used. The anode can be formed by depositing these electrode materials by methods such as vapor deposition or sputtering. Alternatively, a desired pattern may be formed on the formed thin film using photolithography, or, if pattern precision is not required (approximately 100 μm or more), a pattern may be formed using a mask of the desired shape during vapor deposition or sputtering of the electrode material. Alternatively, when a coatable material such as an organic conductive compound is used, wet film formation methods such as printing or coating can also be used. However, if the organic solid-state semiconductor laser is configured to extract laser light by transmitting it through the anode, the anode must be transparent. Specifically, to form a transparent anode, for example, the above-mentioned conductive transparent materials can be used as the anode, a thin film formed of a metal or alloy with a thickness of 5 to 100 nm can be used as the anode, or an electrode having the DMD structure described below can be used as the anode. The thickness of the metal or alloy thin film is, for example, 40 nm or less, for example, 5 to 30 nm, for example, 12 to 25 nm. The sheet resistance as an anode is, for example, several hundred Ω / □ or less. Furthermore, the film thickness, although depending on the material, is usually selected in the range of 10 to 1000 nm, for example, 10 to 200 nm.

[0131] (Electron Injection Section) The electron injection section has the function of injecting electrons. For example, when a hole blocking layer is provided adjacent to the electron injection section, electrons are injected from the electron injection section to the hole blocking layer, and the electrons transported through the hole blocking layer are injected into the light-emitting layer. When a spacer layer is provided between the hole blocking layer and the electron injection section and adjacent to the electron injection section, electrons are injected from the electron injection section to the spacer layer, and the electrons transported through the spacer layer and the hole blocking layer are injected into the light-emitting layer.

[0132] In one aspect of the present technology, the electron injection section of the first embodiment is an electrode, for example, a metal electrode. The material of the metal electrode may be any of a simple metal element, a mixture of two or more simple metal elements, an alloy of two or more metal elements, a mixture of a simple metal element and an alloy, and a mixture of two or more alloys. For the electrode serving as the electron injection section (hereinafter referred to as the "cathode"), a metal (referred to as an electron injection metal) or alloy having a smaller work function than the electrode material used for the anode can be used. Furthermore, an electrically conductive compound or a mixture thereof can also be used as the electrode material for the cathode. Specific examples of such cathode materials include sodium, sodium-potassium alloy, magnesium, lithium, a magnesium / copper mixture, a magnesium / silver mixture, a magnesium / aluminum mixture, a magnesium / indium mixture, and aluminum / aluminum oxide (Al ２ O ３ Among these, for example, in terms of electron injection property and durability against oxidation, etc., a mixture of an electron injection metal and a second metal which is a metal having a larger work function value and is more stable than the electron injection metal can be used, and examples thereof include a magnesium / silver mixture, a magnesium / aluminum mixture, a magnesium / indium mixture, an aluminum / aluminum oxide (Al ２ O ３) mixture, lithium / aluminum mixture, aluminum, etc. can be used. Furthermore, a coated metal film, in which a coating of lithium fluoride or the like is provided on the surface of a thin film formed from an electron-injecting metal, can also be used as the cathode. The cathode can be formed by depositing these electrode materials by methods such as vapor deposition or sputtering. However, if the laser element is configured to extract laser light by transmitting light through the cathode, the cathode must be transparent. Specifically, to form a transparent cathode, a thin film formed from the above-mentioned electrode material to a thickness of 5 to 100 nm (e.g., 40 nm or less, e.g., 5 to 30 nm, e.g., 12 to 25 nm) can be used as the cathode; a laminated structure (e.g., an ITO / Al / LiF laminated structure) in which the above-mentioned coated metal film is laminated on a thin film of a conductive transparent material exemplified as an anode material can be used as the cathode; or an electrode having the DMD structure described below can be used as the cathode. The sheet resistance of the cathode is, for example, several hundred Ω / □ or less, and the film thickness is usually selected in the range of 10 nm to 5 μm, for example, 50 to 200 nm.

[0133] In one aspect of the present technology, at least one of the electron injection part and the hole injection part is an electrode having a visible light transmittance of 10% or more, for example, 50% or more, for example, 80% or more, or for example, 90% or more.

[0134] (Light-Emitting Layer) The light-emitting layer is a layer in which excitons are generated by the recombination of holes and electrons injected from the hole injection section and electron injection section, respectively, forming a population inversion and causing stimulated emission. The light-emitting layer contains a laser oscillation material (optical gain medium) capable of causing such stimulated emission. The light-emitting layer may be composed solely of the laser oscillation material, or may be a layer in which the laser oscillation material is doped into a host material. The light-emitting layer may also contain a laser oscillation material and a dopant material. Examples of dopant materials include a light-emitting material and a triplet quencher. Doping the light-emitting layer with a light-emitting material can control the wavelength and color of light emitted by the light-emitting layer. Furthermore, doping the light-emitting layer with a triplet quencher suppresses the accumulation of triplet excitons in the light-emitting layer, thereby suppressing the generation of higher-order excited states due to collisions between triplet excitons and the degradation of excited molecules caused by these higher-order excited states. As a result, light-emitting efficiency can be improved. In one aspect of the present technology, the light-emitting layer is a layer composed solely of the laser oscillation material. In one aspect of the present technology, the light-emitting layer is a layer formed by doping a host material with a laser oscillation material. In one aspect of the present technology, the light-emitting layer is a layer formed by mixing a laser oscillation material and a dopant material. In one aspect of the present technology, the light-emitting layer is a layer formed by doping a host material with a laser oscillation material and a dopant material. In one aspect of the present technology, the dopant material is an organic compound. In one aspect of the present technology, the dopant material includes an emitting material. In one aspect of the present technology, the dopant material includes a triplet quencher. In one aspect of the present technology, the dopant material includes an emitting material and a triplet quencher.

[0135] The laser oscillation material can be selected from organic compounds having at least one stilbene unit, where the stilbene unit has the following structure, at least one hydrogen atom of which may be substituted with a substituent:

[0136]

[0137] In one aspect of the present technology, the laser oscillation material is selected from organic compounds having two or more stilbene units. In the two or more stilbene units, the phenyl groups of adjacent stilbene units may be linked by a single bond at the 4- and 4'-positions, or may be linked by a single bond at the 4- and 4'-positions and a methylene group at the 3- and 3'-positions to form a fluorene ring. At least one hydrogen atom of the benzene ring constituting the stilbene unit may be substituted with a substituent (e.g., an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 15 carbon atoms). Furthermore, the hydrogen atom at the 9-position (methylene group) of the fluorene ring may be substituted with two alkyl groups (e.g., having 1 to 10 carbon atoms, e.g., 6 carbon atoms), and a hydrocarbon ring such as a fluorene ring may be spiro-bonded to the 9-position.

[0138] Specific examples of laser oscillation materials that can be used in the present technology are listed below. However, the laser oscillation materials that can be used in the present technology should not be construed as being limited by these specific examples. First, a specific example of a laser oscillation material having a stilbene unit is 4,4'-bis[(N-carbazole)styryl]biphenyl (BSBCz) represented by the following formula. In one embodiment of the present technology, the light-emitting layer contains BSBCz. In one embodiment of the present technology, the light-emitting layer is a layer composed only of BSBCz. In one embodiment of the present technology, the light-emitting layer is a layer formed by doping BSBCz into a host material. The layer formed by doping BSBCz into a host material may further contain a dopant material.

[0139]

[0140] Examples of laser oscillation materials having a stilbene unit include the following compound and a polymer having the following repeating structure: １ and R ２ represents an alkyl group having 1 to 10 carbon atoms, such as a hexyl group. n and m each independently represent an integer of 2 to 20. n and m may be the same or different.

[0141]

[0142] The laser oscillation material can also be selected from organic compounds having at least one fluorene ring. Examples of laser oscillation materials having a fluorene ring include the following compounds and polymers having the following repeating structures: In the following formulas, R represents an alkyl group having 1 to 10 carbon atoms, such as a hexyl group; Me represents a methyl group, hexyl represents a hexyl group, and Oct represents an octyl group; n represents an integer from 2 to 30, such as 2, 3, 4, 5, or 6. Note that compounds having both a stilbene unit and a fluorene ring are shown above as specific examples of laser oscillation materials having a stilbene unit.

[0143]

[0144] The laser oscillation material can also be selected from organic compounds having at least one condensed polycyclic structure (julolidine ring) shown below.

[0145]

[0146] Examples of laser oscillation materials having a julolidine ring include the following compounds.

[0147] By using, for example, a material other than a polymer (a polymer of a monomer) among the above laser oscillation materials, the light emitting layer can be easily formed by vapor deposition.

[0148] The luminescent material used as the dopant material can be, for example, a luminescent organic compound, and may be any of a fluorescent material, a delayed fluorescent material, and a phosphorescent material. In this specification, a "fluorescent material" refers to a luminescent material whose fluorescent emission intensity is higher than its phosphorescence emission intensity when observed at 20°C, and a "phosphorescent material" refers to a luminescent material whose phosphorescence emission intensity is higher than its fluorescence emission intensity when observed at 20°C. A "delayed fluorescent material" refers to a material in which both fluorescence with a short emission lifetime and fluorescence with a long emission lifetime (delayed fluorescence) are observed at 20°C. Ordinary fluorescence (fluorescence other than delayed fluorescence) has an emission lifetime on the order of nanoseconds, while phosphorescence usually has an emission lifetime on the order of milliseconds. Therefore, fluorescence and phosphorescence can be distinguished by their emission lifetimes. Furthermore, luminescent organic compounds other than organometallic complexes are ordinary fluorescent materials or delayed fluorescent materials. Furthermore, the luminescent material used as the dopant material may be an organic compound known as an optical gain medium. However, the compound used as the luminescent material must be different from the compound used as the laser oscillation material in the organic solid-state semiconductor laser. The configuration and driving conditions of the optical resonator of the organic solid-state semiconductor laser used in this technology are designed based on the conditions (e.g., emission wavelength and oscillation threshold) of the organic compound selected as the laser oscillation material so that the organic compound can oscillate as a laser.

[0149] The emission wavelength and color of the light-emitting material are appropriately selected depending on the oscillation wavelength of the laser oscillation material and the target emission wavelength and color. For example, the emission wavelength of the light-emitting material may be selected from the visible region, infrared region, or ultraviolet region.

[0150] Specific examples of luminescent materials include fluorene-based molecules, styrylbenzene-based molecules, carbazole-styrylbiphenyl compounds, TADF materials (thermally activated delayed fluorescent materials), star polymers, polyfluorenes, phenylene vinylene polymers, and ladder polymers described in Adv. Photonics Res. 2021, 2, 2000155, and examples of luminescent molecules described in CCS Chem. 2020, 2, 1203-1216. Here, "star polymer" refers to a polymer with three or more branched chains extending radially from a common center (e.g., a benzene core, a pyrene core, or a truxene core), and "ladder polymer" refers to a polymer in which monomer units are linked by two or more bonds. Representative examples of these compounds are listed below. Unless otherwise specified, n represents an integer between 2 and 20.

[0151]

[0152] These light-emitting materials may be used alone or in combination of two or more.

[0153] The triplet quencher can be a compound having a lower minimum excited triplet energy than the laser oscillation material, for example, a compound having a lower minimum excited triplet energy than the laser oscillation material and a higher minimum excited singlet energy than the laser oscillation material. The triplet quencher can be selected from organic compounds having an anthracene ring, for example. Specific examples of triplet quenchers having an anthracene ring are shown below.

[0154] As the host material, an organic compound having at least one of the excited singlet energy and the excited triplet energy higher than that of the laser oscillation material can be used. This allows the singlet and triplet excitons generated in the laser oscillation material to be confined within the molecules of the laser oscillation material, thereby lowering the threshold current density for laser oscillation. However, even if the singlet and triplet excitons cannot be sufficiently confined, they may still contribute to lowering the threshold and improving the laser characteristics. Therefore, any host material that can achieve lowering the threshold and improving the laser characteristics can be used in this technology without any particular restrictions. In the organic solid-state semiconductor laser of this technology, light stimulated and emitted by the laser oscillation material propagates through the light-emitting layer due to the action of an optical resonator or the like, and is emitted to the outside as laser light. The light emitted by the laser element may include spontaneous emission light or amplified spontaneous emission light from the laser oscillation material, or may include light emitted from the host material, but for example, laser light is the main component. When a host material is used, the amount of the laser oscillation material contained in the light-emitting layer is, for example, 0.1 wt % or more, for example, 0.5 wt % or more, for example, 1 wt % or more, and for example, 99 wt % or less, for example, 90 wt % or less, for example, 70 wt % or less, for example, 50 wt % or less, 30 wt % or less, for example, 15 wt % or less. As the host material in the light-emitting layer, for example, an organic compound having hole transport ability and electron transport ability, preventing the emission wavelength from shifting to a longer wavelength, and having a high glass transition temperature can be used. As the host material, an appropriate host material can be selected from known host materials in consideration of the energy conditions and physical properties as described above.

[0155] Furthermore, materials (lasing materials and host materials) constituting the light-emitting layer can have hole mobility equivalent to or greater than that of BSBCz. This allows holes to efficiently accumulate near the interface between the light-emitting layer and the hole-blocking layer, allowing carrier recombination to occur more intensively in this region. Here, the hole mobility of the light-emitting layer can be greater than the electron mobility, for example, 10 times or more greater than the electron mobility. The thickness of the light-emitting layer can be, for example, 10 nm or more, for example, 30 nm or more, 50 nm or more, or 70 nm or more, or can be, for example, less than 200 nm, for example, 150 nm or less, or 100 nm or less. The thickness of the light-emitting layer can be selected, for example, from the range of 10 nm or more to less than 200 nm.

[0156] (Hole Blocking Layer) The hole blocking layer can be provided adjacent to the light-emitting layer, for example, in contact with the light-emitting layer. In a preferred embodiment of the present technology, the hole blocking layer is formed along a flat interface of the light-emitting layer. As shown in FIG. 30( b), the hole blocking layer 55 has the function of preventing holes (+) transported through the light-emitting layer 54 toward the hole blocking layer 55 from migrating toward the electron injection section 57 beyond the interface between the light-emitting layer 54 and the hole blocking layer 55. This causes holes to remain near the interface between the light-emitting layer 54 and the hole blocking layer 55, and recombine with electrons (-) that have migrated from the hole blocking layer 55 into the light-emitting layer 54. As a result, carrier recombination occurs intensively near this interface, efficiently generating stimulated emission light, and laser radiation with narrow peak widths in both the emission spectrum and the angular light intensity distribution can be realized. Note that, while the effects of the present technology are described here using the laser element shown in FIG. 30 as an example, the configuration of the organic solid-state semiconductor laser of the present technology should not be interpreted as being limited by this specific example. To achieve this hole-blocking function, a material is selected for the hole-blocking layer such that the absolute value of the HOMO (Highest Occupied Molecular Orbital) energy of the hole-blocking layer is greater than the absolute value of the HOMO energy of the light-emitting layer. For example, the absolute value of the HOMO energy of the hole-blocking layer may be greater than the absolute value of the HOMO energy of the light-emitting layer by 0.1 eV or more, 0.2 eV or more, or 0.4 eV or more. The hole-blocking layer may also be composed of a material with low hole mobility. Specific examples of materials for the hole-blocking layer include TPBi ([1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene]) and T2T (2,4,6-tris([1,1'-biphenyl]-3-yl))-1,3,5-triazine. Alternatively, the material for the hole blocking layer can be selected from the group consisting of materials having a hole mobility equal to or lower than that of TPBi and materials having a hole mobility equal to or lower than that of T2T.The material for the hole blocking layer can be selected from compounds having a nitrogen-containing aromatic heterocycle, or from compounds having a structure in which a nitrogen-containing aromatic heterocycle is bonded to an aromatic hydrocarbon ring. Examples of nitrogen-containing aromatic heterocycles include nitrogen-containing six-membered aromatic rings such as pyridine, pyrazine, pyrimidine, pyridazine, and triazine rings; azole rings such as imidazole, thiazole, and oxazole rings; and fused rings in which these nitrogen-containing six-membered aromatic rings or azole rings are fused with an aromatic hydrocarbon ring. The aromatic hydrocarbon ring may be a single ring or a fused ring in which two or more rings are fused. In the case of a fused ring, the number of fused rings can be selected from the range of 2 to 6. Specific examples of the ring include a benzene ring and a naphthalene ring. The thickness of the hole blocking layer is, for example, 1 nm or more, such as 3 nm or more, and may be, for example, 5 nm or more or 8 nm or more, or may be, for example, 80 nm or less, for example, 30 nm or less, or 15 nm or less.

[0157] (Spacer Layer) The spacer layer used in the first embodiment is a layer provided between the hole blocking layer and the electron injection section as needed. By disposing the spacer layer between the hole blocking layer and the electron injection section, a space is created between the carrier recombination region (near the interface between the light-emitting layer and the hole blocking layer) and the electron injection section, which can prevent light generated in the carrier recombination region from being lost due to the formation of surface plasmon polaritons on the electrode surface, as well as light loss due to absorption or scattering at the electrode. The spacer layer may have a single-layer structure or a multi-layer structure. Furthermore, when one or more layers are provided between the light-emitting layer and the hole injection section, the total thickness of the spacer layer can be at least twice the total thickness of the layers between the light-emitting layer and the hole injection section, for example, at least 2.5 times or at least 3 times. For a description of the one or more layers provided between the light-emitting layer and the hole injection section, please refer to the description in the "Other Layers" section below. By forming the spacer layer thicker than the layer between the light-emitting layer and the hole injection section, the electron migration distance becomes longer than the hole migration distance, preventing electrons from moving too far within the light-emitting layer. As a result, carrier recombination can be concentrated in a narrower region. Furthermore, the spacer layer can be made of, for example, a material with a lower refractive index than the light-emitting layer. This allows light from the light-emitting layer to be efficiently reflected at the interface of the spacer layer on the light-emitting layer side, thereby more reliably suppressing light loss in the electrodes as described above. The spacer layer used in the first embodiment can be, for example, a layer (electron transport layer) with electron transport properties that can transport electrons injected from the electron injection section to the hole blocking layer. Below, an electron transport layer will be described as an example of a spacer layer.

[0158] (Electron Transport Layer) TPBi is a specific example of a material for the electron transport layer. Alternatively, the material for the electron transport layer can be selected from a group of electron-transporting compounds having electron mobility equivalent to or lower than that of TPBi. The low electron mobility of the electron transport layer prevents electrons from moving too far within the light-emitting layer, allowing carrier recombination to occur in a more concentrated area. The material for the electron transport layer can also be selected from a group of compounds having a nitrogen-containing aromatic heterocycle, for example, a group of compounds having a structure in which a nitrogen-containing aromatic heterocycle and an aromatic hydrocarbon ring are bonded. For details and specific examples of the nitrogen-containing aromatic heterocycle and the aromatic hydrocarbon ring, please refer to the description of the nitrogen-containing aromatic heterocycle and the aromatic hydrocarbon ring in the hole-blocking layer section. However, the material for the electron transport layer can be different from the material for the hole-blocking layer. In one aspect of the present technology, the electron transport layer is a layer having a higher absolute value of HOMO energy than the light-emitting layer. Specifically, the absolute value of the HOMO energy of the electron transport layer may be larger than the absolute value of the HOMO energy of the light-emitting layer by 0.1 eV or more, for example, 0.2 eV or more. The thickness of the electron transport layer may be, for example, 10 nm or more, for example, 20 nm or more, for example, 40 nm or more, or 60 nm or more, and may be, for example, 100 nm or less, for example, 80 nm or less.

[0159] (Other Layers) The organic solid-state semiconductor laser of the first embodiment may have one or more layers between the light-emitting layer and the hole injection section, as necessary. Examples of layers provided between the light-emitting layer and the hole injection section include a hole injection layer and a hole transport layer. The hole injection layer has the function of lowering the hole injection barrier in the hole injection section, and the hole transport layer has the function of transporting holes injected from the hole injection section to the light-emitting layer side. The hole transport layer may be a hole injection transport layer having a hole injection function. Examples of materials for the hole transport layer include triazole derivatives, oxadiazole derivatives, imidazole derivatives, carbazole derivatives, indolocarbazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aniline-based copolymers, and conductive polymer oligomers, particularly thiophene oligomers. For example, the material may be selected from a group of compounds consisting of porphyrin compounds, aromatic tertiary amine compounds, and styrylamine compounds, or may be selected from a group of compounds consisting of aromatic tertiary amine compounds. A specific example of a material for the hole transport layer is NPD. In addition, the material for the hole transport layer may be selected from a group of compounds having a hole mobility equivalent to or higher than that of NPD. A specific example of the material for the hole injection layer is HATCN ([dipyrazino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile]). Alternatively, the material for the hole injection layer can be selected from a group of compounds having a LUMO level or HOMO level between the Fermi level of the hole injection portion and the HOMO level of the light-emitting layer. Furthermore, a layer composed of a material having a hole mobility equivalent to or higher than that of HATCN may be provided between the light-emitting layer and the hole injection portion.

[0160] (Optical Resonator) The optical resonator has the function of propagating emitted light within the light-emitting layer. The optical resonator may be a distributed feedback (DFB) optical resonator or a distributed Bragg reflector (DBR) optical resonator that reflects light using a diffraction grating, or a Fabry-Perot optical resonator composed of a reflecting mirror and a partially reflecting mirror arranged opposite each other. The optical resonator may also be a circular diffraction grating or a striped diffraction grating that functions as a control member. The diffraction grating that constitutes the optical resonator is designed to satisfy the following Bragg equation. The diffraction grating used in the optical resonator may be any of a first-order diffraction grating where m is 1, a second-order diffraction grating where m is 2, or a third-order diffraction grating where m is 3, or may even be a higher-order diffraction grating. It may also be a mixed-order diffraction grating that combines diffraction gratings of different orders. Bragg equation: mλ Ｂｒａｇｇ = 2n ｅｆｆ Λ ｍ where m is the diffraction order, λ Ｂｒａｇｇ is the Bragg wavelength, n ｅｆｆ is the effective refractive index, Λ ｍis the period of the diffraction grating. In one aspect of the present technology, the diffraction grating constituting the optical resonator is a diffraction grating having a periodic uneven structure in which grating protrusions and recesses (grating recesses) partitioned by the grating protrusions are periodically arranged. Such a diffraction grating may be a one-dimensional diffraction grating in which linear grating protrusions (protrusions) are arranged in the horizontal direction, a two-dimensional diffraction grating in which linear grating protrusions are arranged vertically and horizontally and intersect, a two-dimensional diffraction grating in which rectangular grating protrusions are scattered in a matrix, or a three-dimensional diffraction grating in which two-dimensional diffraction gratings are stacked in the vertical direction. Here, the diffraction grating may be arranged so that at least a portion of the grating protrusions penetrate into the light-emitting layer from the hole injection section side of the light-emitting layer. In the following description, the portion of the grating protrusion that penetrates into the light-emitting layer is referred to as the "penetration portion." The length of the penetration portion of the grating protrusion can be selected from a range shorter than the thickness of the light-emitting layer, for example, a range shorter than the thickness of the light-emitting layer by 15 nm or more. This ensures a carrier recombination region in the region where the lattice protrusions do not penetrate, allowing carrier recombination and stimulated emission to occur efficiently. Such a diffraction grating can be formed, for example, on the surface of the electrode constituting the hole injection section, facing the light-emitting layer. In this case, the lattice protrusions may be formed on the surface of the electrode facing the light-emitting layer, with the electrode surface exposed from the bottom of the lattice recesses. Alternatively, the diffraction grating can be disposed between the region of the light-emitting layer that serves as the carrier recombination region and the hole injection section. Alternatively, the base ends of the lattice protrusions of the diffraction grating can be disposed at the interface of the light-emitting layer facing the hole injection section or closer to the hole injection section than the interface, and the hole blocking layer can be disposed between the light-emitting layer and the electron injection section, adjacent to the light-emitting layer. The lattice protrusions can be formed, for example, from an insulating material. The insulating material may be an inorganic insulating material or an organic insulating material. Specific examples of insulating materials include glass, silicon dioxide, and plastic.

[0161] The grating projections of the diffraction grating can be formed so that their heights are perpendicular to the diffraction grating formation surface. However, as shown in FIG. 32, the grating projections 201 can also be formed at an angle from the perpendicular direction to the diffraction grating formation surface 202s. For example, the grating projections 201 can be formed so that the grating surface 201a has an angle θ (θ<90°) with the light propagation direction (horizontal direction in FIG. 32). This allows for control of the direction of light extracted from the light extraction surface 203s of the organic electroluminescent element (light emission angle θem). Organic electroluminescent elements that emit light obliquely with respect to the in-plane direction of the light extraction surface can be effectively used, for example, as light-emitting elements combined with light guide plates used in AR glasses, or as in-vehicle displays that display different images for the driver and passenger seat. Here, a diffraction grating having tilted grating projections can be designed to satisfy the following modified Bragg condition: A diffraction grating having inclined grating projections can also be used in an organic electroluminescence element that does not have a hole blocking layer or an electron blocking layer.

[0162]

[0163] where Λ is the period of the diffraction grating, θ is the angle between the light propagation direction and the grating plane, and n ｅｆｆ is the effective refractive index, m is the diffraction order, and λ is the wavelength.

[0164] Second Embodiment Next, a second embodiment of the organic solid-state semiconductor laser will be described. The organic solid-state semiconductor laser of the second embodiment is configured by stacking at least a hole injection section, an electron blocking layer, a light-emitting layer, and an electron injection section in this order, and includes an optical resonator that propagates emitted light within the light-emitting layer and a control member that controls light extraction characteristics. Here, the control member may serve both as the control member and the optical resonator. That is, in one aspect of the present technology, the organic solid-state semiconductor laser of the second embodiment is configured by stacking at least a hole injection section, a light-emitting layer, a hole blocking layer, and an electron injection section in this order, and includes a control member that serves both as the control member and the optical resonator. For a description of the control member, examples of a control member that also serves as an optical resonator, and examples of other control members, please refer to the description in the above section (Control Member). The organic solid-state semiconductor laser of the second embodiment may further include a spacer layer between the electron blocking layer and the hole injection section, or one or more layers between the light-emitting layer and the electron injection section. Here, the electron blocking layer, the light-emitting layer, the spacer layer, and one or more layers disposed between the light-emitting layer and the electron injection portion can be organic layers. A specific structural example of the second embodiment is shown in Fig. 31. In Fig. 31, 61 represents a hole injection portion, 62 represents a hole transport layer, 63 represents an electron blocking layer, 64 represents a light-emitting layer, 65 represents an electron transport layer, 66 represents an electron injection layer, 67 represents an electron injection portion, and 68 represents a diffraction grating that constitutes an optical resonator. Here, the hole transport layer 62 constitutes a spacer layer, and the electron transport layer 65 and the hole injection layer 66 correspond to the above-mentioned "one or more layers disposed between the light-emitting layer and the electron injection portion."

[0165] In the organic solid-state semiconductor laser of the second embodiment, by having a circular diffraction grating or a striped diffraction grating that serves as both a control member and an optical resonator, a light intensity distribution with a sharp peak can be obtained on the light extraction surface, and when used to form pixels in a display device, optical crosstalk between adjacent pixels can be effectively suppressed or prevented. Furthermore, when a striped diffraction grating is used, light generated in the light-emitting layer can be converted into linearly polarized light and efficiently extracted from the light extraction surface.

[0166] Furthermore, the organic solid-state semiconductor laser of the second embodiment may have a partition wall or a photonic crystal material as a control member in addition to the optical resonator. In this case, the optical resonator may also function as the control member, or may not function as the control member. By using a partition wall or a photonic crystal material as the control member, a light intensity distribution with a sharp peak can be obtained on the light extraction surface, and when used to form pixels of a display device, optical crosstalk between adjacent pixels can be effectively suppressed or prevented. Furthermore, when a partition wall is used, adjacent pixels are electrically insulated from each other, so electrical crosstalk can be effectively suppressed or prevented.

[0167] Each layer and each member constituting the organic solid-state semiconductor laser of the second embodiment will be described below. For an explanation of the control member, please refer to the description in the (Control Member) section above. For an explanation of the substrate and the light-emitting layer, please refer to the descriptions in the "Substrate" and "Light-emitting Layer" sections of the first embodiment. The organic solid-state semiconductor laser of the second embodiment may have a hole injection section, an electron blocking layer, a light-emitting layer, and an electron injection section stacked in this order on a substrate, or may have an electron injection section, a light-emitting layer, an electron blocking layer, and a hole injection section stacked in this order on a substrate.

[0168] (Hole injection section) The hole injection section has the function of injecting holes. For example, when an electron blocking layer is provided adjacent to the hole injection section, holes are injected from the hole injection section to the electron blocking layer, and the holes transported through the electron blocking layer are injected into the light-emitting layer. Furthermore, when a spacer layer is provided between the electron blocking layer and the hole injection section so as to be adjacent to the hole injection section, holes are injected from the hole injection section to the spacer layer, and the holes transported through the spacer layer and the electron blocking layer are injected into the light-emitting layer. In one aspect of the present technology, the hole injection section of the second embodiment is an electrode, for example, a transparent electrode. For a description and specific examples of the electrode (anode) that is the hole injection section, please refer to the description of the "hole injection section" in the first embodiment.

[0169] (Electron Injection Section) The electron injection section has the function of injecting electrons into the laser element. For example, when a light-emitting layer is provided adjacent to the electron injection section, electrons are directly injected from the electron injection section into the light-emitting layer. Furthermore, when one or more layers are present between the light-emitting layer and the electron injection section, electrons are injected from the electron injection section into one of the one or more layers adjacent to the electron injection section, and electrons transported through the one or more layers are injected into the light-emitting layer. In one aspect of the present technology, the electron injection section of the second embodiment is an electrode, for example, a metal electrode. For a description and specific examples of the electrode (cathode) that is the electron injection section, please refer to the description of the "electron injection section" in the first embodiment.

[0170] (Electron Blocking Layer) The electron blocking layer can be provided adjacent to the light-emitting layer, for example, in contact with the light-emitting layer. In a preferred embodiment of the present technology, the electron blocking layer is formed along a flat interface of the light-emitting layer. The electron blocking layer has the function of preventing electrons transported through the light-emitting layer toward the electron blocking layer from migrating toward the hole injection portion beyond the interface between the light-emitting layer and the electron blocking layer. As a result, as shown in FIG. 31 , electrons (e-) are retained near the interface between the light-emitting layer and the electron blocking layer and recombine with holes that have migrated from the electron blocking layer into the light-emitting layer. As a result, carrier recombination occurs intensively near this interface, efficiently generating stimulated emission light, and laser radiation with narrow peak widths in both the emission spectrum and the angular light intensity distribution can be realized. Note that, while the effects of the present technology are described here using the laser element shown in FIG. 31 as an example, the configuration of the organic solid-state semiconductor laser of the present technology should not be interpreted as being limited by this specific example. To achieve this electron blocking function, a material is selected for the electron blocking layer such that the absolute value of the LUMO (Lowest Unoccupied Molecular Orbital) energy of the electron blocking layer is smaller than the absolute value of the LUMO energy of the light-emitting layer. For example, the absolute value of the LUMO energy of the electron blocking layer may be smaller than the absolute value of the LUMO energy of the light-emitting layer by 0.1 eV or more, 0.2 eV or more, or 0.4 eV or more. The electron blocking layer may also be composed of a material with low electron mobility. A specific example of a material for the electron blocking layer is N,N'-di(1-naphthyl)-N,N'-diphenylbenzidine (NPD). Alternatively, the material for the electron blocking layer may be selected from a group of materials having electron mobility equivalent to or lower than that of NPD. The thickness of the electron blocking layer is, for example, 1 nm or more, for example, 3 nm or more, and may be, for example, 5 nm or more, or 8 nm or more, and may be, for example, 80 nm or less, or, for example, 30 nm or less, or 15 nm or less.

[0171] (Spacer Layer) The spacer layer used in the second embodiment is a layer provided between the electron blocking layer and the hole injection section as needed. By disposing the spacer layer between the electron blocking layer and the hole injection section, a space is created between the carrier recombination region (near the interface between the light-emitting layer and the electron blocking layer) and the hole injection section, which can prevent light generated in the carrier recombination region from being lost due to the formation of surface plasmon polaritons on the electrode surface, as well as light loss due to absorption or scattering at the electrode. The spacer layer may have a single-layer structure or a multi-layer structure. Furthermore, when one or more layers are provided between the light-emitting layer and the electron injection section, the total thickness of the spacer layer can be at least twice the total thickness of the layers between the light-emitting layer and the electron injection section, for example, at least 2.5 times or at least 3 times. For a description of the one or more layers provided between the light-emitting layer and the electron injection section, please refer to the description in the "Other Layers" section below. By forming the spacer layer thicker than the layer between the light-emitting layer and the electron injection section, the hole migration distance becomes longer than the electron migration distance, preventing holes from moving too far within the light-emitting layer. As a result, carrier recombination can be concentrated in a narrower region. Furthermore, the spacer layer can be made of, for example, a material with a lower refractive index than the light-emitting layer. This allows light from the light-emitting layer to be efficiently reflected at the interface of the spacer layer on the light-emitting layer side, thereby more reliably suppressing light loss in the electrodes as described above. The spacer layer used in the second embodiment can be, for example, a layer (hole transport layer) with hole transport properties that can transport holes injected from the hole injection section to the electron blocking layer. Below, a hole transport layer will be described as an example of a spacer layer.

[0172] (Hole Transport Layer) The material for the hole transport layer can be, for example, a hole transport compound having a hole mobility equal to or lower than that of HATCN. The low hole mobility of the hole transport layer prevents holes from moving too far through the light-emitting layer, allowing carrier recombination to occur in a more concentrated area. The material for the hole transport layer can be a material different from the material for the electron blocking layer. In one aspect of the present technology, the hole transport layer is a layer having a smaller absolute value of LUMO energy than the light-emitting layer. Specifically, the absolute value of the LUMO energy of the hole transport layer may be 0.1 eV or more smaller than the absolute value of the LUMO energy of the light-emitting layer, for example, 0.2 eV or more smaller. The thickness of the hole transport layer is, for example, 10 nm or more, for example, 20 nm or more, and may be, for example, 40 nm or more or 60 nm or more, or may be, for example, 100 nm or less, for example, 80 nm or less.

[0173] (Other Layers) The organic solid-state semiconductor laser of the second embodiment may have one or more layers between the light-emitting layer and the electron injection section, if necessary. Examples of layers provided between the light-emitting layer and the electron injection section include an electron injection layer and an electron transport layer. The electron injection layer has the function of lowering the electron injection barrier in the electron injection section, and the electron transport layer has the function of transporting electrons injected from the electron injection section to the light-emitting layer. The electron transport layer may also be an electron injection transport layer with an electron injection function. Examples of materials for the electron transport layer include nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, and oxadiazole derivatives. Furthermore, among the above oxadiazole derivatives, thiadiazole derivatives in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, and quinoxaline derivatives having a quinoxaline ring known as an electron-withdrawing group can also be used as electron transport materials. Furthermore, polymer materials in which these materials are introduced into the polymer chain or in which these materials form the polymer main chain can also be used. TPBi is a specific example of a material for the electron transport layer. In addition, materials for the electron transport layer can be selected from a group of compounds having electron mobility equivalent to or higher than that of TPBi.

[0174] (Optical Resonator) For a description of the optical resonator, the description of the "Optical Resonator" in the first embodiment above can be referenced, except for the description of the diffraction grating arrangement and the penetration portions of the grating projections. In the diffraction grating used in the second embodiment, for example, at least a portion of the grating projections can be arranged so as to penetrate into the light-emitting layer from the electron injection portion side of the light-emitting layer. The length of the penetration portion of the grating projections that penetrate into the light-emitting layer can be selected from a range in which the penetration length is shorter than the thickness of the light-emitting layer, for example, from a range in which the penetration length is 15 nm or more shorter than the thickness of the light-emitting layer. This ensures a carrier recombination region in the region not penetrated by the grating projections, allowing carrier recombination and stimulated emission to occur efficiently here. Such a diffraction grating can be formed, for example, on the surface of the electrode that constitutes the electron injection portion, facing the light-emitting layer. In this case, the grating projections can be formed on the surface of the electrode that faces the light-emitting layer, and the electrode surface can be exposed from the bottom of the grating depressions. Alternatively, the diffraction grating may be disposed between the region of the light-emitting layer that serves as the carrier recombination region and the electron injection section, and the base ends of the grating projections of the diffraction grating may be disposed at the interface of the light-emitting layer on the electron injection section side or closer to the electron injection section than the interface, and the electron blocking layer may be disposed between the light-emitting layer and the hole injection section and adjacent to the light-emitting layer.

[0175] The organic solid-state semiconductor lasers of the first and second embodiments may be surface-emitting laser elements that extract laser light from the surface (light extraction surface), or edge-emitting laser elements that extract laser light from the end surface (light extraction surface). Furthermore, if the laser element is a surface-emitting laser element, it may be a bottom-emission type that extracts laser light from the surface (light extraction surface) on the substrate side, or a top-emission type that extracts laser light from the surface (light extraction surface) opposite the substrate. Furthermore, the organic solid-state semiconductor lasers of the first and second embodiments may be dual-emission laser elements in which the back side is visible from the front side. Note that, although laser light may leak from surfaces other than the surface set as the light extraction surface in each type of laser element, for example, the majority of the laser light (more than 50%) is emitted from the set light extraction surface.

[0176] In an organic solid-state semiconductor laser in which the electron injection section is located on the opposite side of the substrate across the light-emitting layer, a top-emission organic solid-state semiconductor laser can be provided by configuring the electron injection section from a material with high light transmittance. In one aspect of the present technology, the electron injection section is a DMD structure with high light transmittance or a thin Ag layer (for example, a thickness of 40 nm or less, for example, 5 to 30 nm, for example, 12 to 25 nm). Furthermore, a bottom-emission organic solid-state semiconductor laser can be provided by configuring the hole injection section from a material with high light transmittance. In one aspect of the present technology, the hole injection section is an ITO layer. Furthermore, a dual-emission organic solid-state semiconductor laser can be provided by configuring both the electron injection section and the hole injection section from materials with high light transmittance. Meanwhile, in an organic solid-state semiconductor laser in which the hole injection section is located on the opposite side of the substrate across the light-emitting layer, a top-emission organic solid-state semiconductor laser can be provided by configuring the hole injection section from a material with high light transmittance. In one aspect of the present technology, the hole injection section is a DMD structure with high light transmittance or an ITO layer. Furthermore, by forming the electron injection section from a material with high light transmittance, a bottom-emission organic solid-state semiconductor laser can be provided. In one aspect of the present technology, the electron injection section has a laminated structure of ITO / Al / LiF. Here, the thicknesses of Al and LiF are selected from the range of 0.5 to 10 nm. Furthermore, by forming both the hole injection section and the electron injection section from materials with high light transmittance, a dual-emission organic solid-state semiconductor laser can be provided. Here, the term "DMD structure" is an abbreviation for dielectric-metal-dielectric structure, and refers to a laminated structure of dielectric / metal / dielectric. The DMD structure can be employed in the present technology as an electrode utilizing interference of the laminated structure. Ag or the like can be used as the metal constituting the DMD structure. Furthermore, MoO ３ , ITO, ZnS, InZnSnO, WO ３ The materials of the two dielectric layers disposed on both sides of the metal layer may be the same or different. In one aspect of the present technology, the materials of the two dielectric layers of the DMD structure are the same. As the DMD structure, MoO３ / Ag / MoO ３ In addition, ITO / Ag / ITO, ZnS / Ag / ZnS, ZnO / Ag / ZnO, InZnSnO / Ag / InZnSnO, ITO / Ag / WO ３ , ZnO / Ag / WO ３ , W.O. ３ / Ag / WO ３ The thicknesses of the two dielectric layers disposed on both sides of the metal layer may be the same or different.

[0177] Furthermore, by controlling the refractive index of each layer constituting the organic solid-state semiconductor laser, the light generated in the laser oscillation material can be confined within the optical resonator. This reduces the optical loss at the electrodes and lowers the laser oscillation threshold. Specifically, the refractive index of each layer can be controlled in the following manner.

[0178] According to one aspect of the present technology, an organic solid-state semiconductor laser is configured as a first embodiment, and includes a circular diffraction grating that also serves as a control member and an optical resonator. According to one aspect of the present technology, an organic solid-state semiconductor laser is configured as a first embodiment, and includes a circular diffraction grating that also serves as a control member and an optical resonator, and a partition or a photonic crystal material as the control member. According to one aspect of the present technology, an organic solid-state semiconductor laser is configured as a first embodiment, and includes a striped diffraction grating that also serves as a control member and an optical resonator. According to one aspect of the present technology, an organic solid-state semiconductor laser is configured as a first embodiment, and includes a striped diffraction grating that also serves as a control member and an optical resonator, and a partition or a photonic crystal material as the control member.

[0179] In one aspect of the present technology, the organic solid-state semiconductor laser is configured as a first embodiment, and the refractive index of a layer (hole blocking layer, or hole blocking layer and spacer layer) provided between the light-emitting layer and the electron injection section is smaller than the refractive index of the light-emitting layer. In another aspect of the present technology, the organic solid-state semiconductor laser is configured as a second embodiment, and the refractive index of a layer (e.g., electron injection layer or electron transport layer) provided between the light-emitting layer and the electron injection section is smaller than the refractive index of the light-emitting layer. In the organic solid-state semiconductor laser of this aspect, light generated in the laser oscillation material is efficiently reflected at an interface between the light-emitting layer and a layer adjacent to the light-emitting layer on the electron injection section side, and is confined within an optical resonator (refractive index waveguiding), or gain waveguiding is formed, thereby enabling efficient laser oscillation. Furthermore, the generated laser light can be extracted by transmitting through, for example, a layer between the light-emitting layer and the hole injection section, the hole injection section, or the substrate. Therefore, the organic solid-state semiconductor laser of these aspects can be used, for example, as a bottom-emission laser element.

[0180] In one aspect of the present technology, the organic solid-state semiconductor laser is configured as a first embodiment, and the refractive index of a layer (e.g., a hole injection layer or a hole transport layer) provided between the light-emitting layer and the hole injection section is smaller than the refractive index of the light-emitting layer. In another aspect of the present technology, the organic solid-state semiconductor laser is configured as a second embodiment, and the refractive index of a layer (e.g., an electron blocking layer, or an electron blocking layer and a spacer layer) provided between the light-emitting layer and the hole injection section is smaller than the refractive index of the light-emitting layer. In the organic solid-state semiconductor laser of this aspect, light generated in the laser oscillation material is efficiently reflected at an interface between the light-emitting layer and a layer adjacent to the light-emitting layer on the hole injection section side, and is confined within an optical resonator (refractive index waveguiding), or gain waveguiding is formed, thereby enabling efficient laser oscillation. Furthermore, the generated laser light can be extracted, for example, by passing through a layer between the light-emitting layer and the electron injection section or the electron injection section. Therefore, the organic solid-state semiconductor laser of these aspects can be used, for example, as a top-emission laser element.

[0181] In one aspect of the present technology, the organic solid-state semiconductor laser is configured as a first embodiment, and the refractive indexes of the layer provided between the light-emitting layer and the electron injection section and the layer provided between the light-emitting layer and the hole injection section are both smaller than the refractive index of the light-emitting layer. In another aspect of the present technology, the organic solid-state semiconductor laser is configured as a second embodiment, and the refractive indexes of the layer provided between the light-emitting layer and the electron injection section and the layer provided between the light-emitting layer and the hole injection section are both smaller than the refractive index of the light-emitting layer. In this organic solid-state semiconductor laser, light generated in the laser oscillation material is efficiently reflected at interfaces between the light-emitting layer and adjacent layers on both sides thereof and confined within the optical resonator, allowing the light to travel laterally within the light-emitting layer and efficiently generate laser oscillation. In another aspect of the present technology, the organic solid-state semiconductor laser is configured as the first or second embodiment, and the gain is high in the central portion of the lateral path of the light-emitting layer. In this organic solid-state semiconductor laser, light passing through the central portion of the lateral path is strongly amplified, so that light naturally travels along the lateral path (high-gain region). In the organic solid-state semiconductor lasers of these aspects, it is sufficient that light propagates laterally in the light-emitting layer, and the final light extraction direction can be vertical. These organic solid-state semiconductor lasers are characterized in that, in the first embodiment, light propagates laterally, while the movement of holes proceeding vertically is hindered (blocked) by the hole blocking layer, and in the second embodiment, light propagates laterally, while the movement of electrons proceeding vertically is hindered (blocked) by the electron blocking layer.

[0182] As described above, the organic solid-state semiconductor laser of the present technology includes a hole blocking layer or an electron blocking layer, which causes carrier recombination to occur intensively near the interface between the light-emitting layer and the hole blocking layer or near the interface between the light-emitting layer and the electron blocking layer, thereby reducing the peak width of the emission spectrum and the peak width of the angular light intensity distribution. As a result, an organic solid-state semiconductor laser with excellent laser characteristics such as laser efficiency and monochromaticity is realized. Here, in this specification, the term "peak width of the emission spectrum" refers to the full width at half maximum (FWHM) of the most intense emission peak among the emission peaks appearing in the light intensity distribution (emission spectrum) versus wavelength, and the term "peak width of the angular light intensity distribution" refers to the full width at half maximum (FWHM) of the most intense emission peak among the emission peaks appearing in the light intensity distribution measured by changing the angle of the light-receiving element. The peak width of the emission spectrum observed in the organic solid-state semiconductor laser of the present technology is, for example, 10 nm or less, for example, 7 nm or less, for example, 5 nm or less, for example, 4 nm or less, for example, 3 nm or less, for example, 2 nm or less, or for example, 1 nm or less. The peak width of the angular light intensity distribution observed in the organic solid-state semiconductor laser of the present technology is, for example, 10° or less, for example, 7° or less, for example, 5° or less, for example, 4° or less, for example, 3° or less, for example, 2° or less, or for example, 1° or less.

[0183] <Display Device> The display device of the present technology has a plurality of pixels, and the plurality of pixels are composed of organic electroluminescence elements with controlled light extraction characteristics or organic solid-state semiconductor lasers with control members. For descriptions of each element constituting a pixel, please refer to the above sections <Method for controlling the light extraction characteristics of an organic electroluminescence element> and <Organic solid-state semiconductor laser>. The plurality of pixels may include a plurality of pixels of different colors, or may include a plurality of combinations of a plurality of pixels of different colors. An example of a combination of a plurality of pixels of different colors is a combination of red pixels, green pixels, and blue pixels.

[0184] For example, when an organic electroluminescent element or control member with controlled light extraction characteristics according to this embodiment is used as the light-emitting portion of a pixel in AR glasses or VR glasses, the following effects can be obtained. First, because the optical system of AR glasses is designed compactly, the NA (numerical aperture) of the optical system is also small. When an organic electroluminescent element or control member with controlled light extraction characteristics according to this embodiment is used as the light-emitting portion of such AR glasses, the half-width of the angular light intensity distribution peak of the emitted light from the element is narrow, allowing the emitted light to be efficiently incident on an optical system with a small NA. This improves the light capture efficiency of the optical system. Furthermore, for example, a diffraction grating may be provided in the optical system of AR glasses for the purpose of guiding light propagating through a light guide in a predetermined direction. When an organic electroluminescent element or control member with controlled light extraction characteristics according to this embodiment is used as the light-emitting portion of such AR glasses, the half-width of the emission wavelength spectrum peak of the light emitted from the element is narrow, thereby improving the diffraction efficiency of light at the diffraction grating. Furthermore, for example, when an organic electroluminescent element or control member with controlled light extraction characteristics according to this embodiment is used as the light-emitting portion of VR glasses or AR glasses, the narrow half-width of the emission wavelength spectrum peak of the light emitted by the element can suppress color bleeding (chromatic aberration) in the optical system. This improves the design freedom of the optical system, for example, by using plastic as the lens material of the optical system. For example, when an organic electroluminescent element or control member with controlled light extraction characteristics according to this embodiment is used as the light-emitting portion of AR glasses, the lateral direction of the light emitted from the light extraction surface can be controlled, allowing for relatively free design of the path of image light from the AR glasses' display to the user's field of vision. This improves the design freedom of AR glasses, for example, making them lighter and improving their design.

[0185] [Examples] The features of the present technology are explained in more detail below with reference to examples. The materials, processing details, processing procedures, etc. shown below can be modified as appropriate without departing from the spirit of the present technology. Therefore, the scope of the present technology should not be interpreted as being limited by the specific examples shown below. The light-emitting characteristics of each element were evaluated using a spectrophotometer (Hamamatsu Photonics: PMA-50) by applying a DC voltage or a rectangular pulse voltage (pulse width: 400 ns, repetition frequency: 1 kHz) to the element, and the current density-voltage characteristics were evaluated at room temperature using an integrating sphere system (Hamamatsu Photonics: A10094).

[0186] [1] Fabrication and Evaluation of Bottom-Emission Organic Solid-State Semiconductor Laser (Example 1) First, a second-order DFB diffraction grating was formed on a glass substrate on which an anode made of indium tin oxide (ITO) with a thickness of 30 nm was formed by electron beam lithography using the following procedure. After UV ozone treatment was performed on the ITO surface, a 100 nm thick SiO2 layer was formed by sputtering. Here, the sputtering was performed under an argon pressure of 0.66 Pa, a temperature of 100°C, and an RF power of 100 W. This SiO2 ２ After cleaning the surface of the layer and performing UV ozone treatment, hexamethyldisilazane (HMDS) was dripped onto the substrate, spin-coated at 4000 rpm for 15 seconds, and then annealed at 120°C for 120 seconds. Subsequently, a resist solution (Zeon Corporation: ZEP520A-7) was dripped onto the substrate, spin-coated at 4000 rpm for 30 seconds, and then baked at 180°C for 240 seconds to form a 70 nm thick resist layer. The resist layer was irradiated with an electron ...

Claims

a hole injection unit that injects holes; an electron injection unit that injects electrons; an organic portion disposed between the hole injection portion and the electron injection portion; Equipped with An organic electroluminescence element, wherein the organic portion includes a light-emitting layer that recombines holes and electrons to emit light, The organic portion has a periodic refractive index structure formed so that the refractive index changes periodically in a predetermined direction in a cross-sectional view cut in a direction perpendicular to the thickness direction, and light from the light-emitting layer resonates in the periodic refractive index structure. 　 the refractive index periodic structure has a periodic structure in which first regions and second regions are alternately arranged in the cross-sectional view, The organic electroluminescent device according to claim 1 , wherein the refractive index of the first region is different from the refractive index of the second region. 　 the refractive index periodic structure has a periodic structure in which the first regions made of a first organic material and the second regions made of a second organic material are alternately arranged in the cross-sectional view, The organic electroluminescent device according to claim 2 , wherein the refractive index of the first organic material is different from the refractive index of the second organic material. 　 the refractive index periodic structure has a periodic structure in which, in the cross-sectional view, the first regions in which the organic material is in a first state in which it is excited and the second regions in which the organic material is in a second state different from the first state are alternately arranged; The organic electroluminescent device according to claim 2 , wherein the refractive index in the first state is different from the refractive index in the second state.

3. The organic electroluminescence element according to claim 2, wherein the period of the refractive index periodic structure is set to satisfy the following Bragg equation: 　　　　　　 ខ្រានក Ｂｒａｇｇ =2. ｅｆｆ L ｍ [where m is the diffraction order, λ Ｂｒａｇｇ is the Bragg wavelength, n ｅｆｆ is the effective refractive index of one of the first and second regions, Λ ｍ represents the pitch of the refractive index periodic structure.] 3. The organic electroluminescence element according to claim 2, wherein the refractive index periodic structure has a periodic structure in which the linear first regions and the linear second regions are alternately arranged in a certain direction in the cross-sectional view.

7. The organic electroluminescence element according to claim 6, wherein the refractive index periodic structure has a periodic structure in which the linear first regions and the linear second regions are alternately arranged in a horizontal direction (X direction) in the cross-sectional view.

7. The organic electroluminescence element according to claim 6, wherein the refractive index periodic structure has a periodic structure in which, in the cross-sectional view, the linear first regions and the linear second regions are alternately arranged in a direction (Y direction) perpendicular to the horizontal direction. 　 The organic electroluminescence element according to claim 2 , wherein the refractive index periodic structure has a pattern in which the first regions are arranged in a honeycomb shape with the second regions as boundaries in the cross-sectional view.

3. The organic electroluminescence element according to claim 2, wherein the refractive index periodic structure has a pattern in which the first region and the second region are arranged alternately in a concentric pattern in the cross-sectional view. 　 The refractive index periodic structure is a periodic structure in which, in the cross-sectional view, the linear first regions and the linear second regions are alternately arranged in a certain direction; a periodic structure having a honeycomb pattern in which the first regions are arranged with the second regions as boundaries in the cross-sectional view; and In the cross-sectional view, the periodic structure has a pattern in which the first region in a circumferential band shape and the second region in a circumferential band shape are alternately arranged in a concentric circle shape.

3. The organic electroluminescence device according to claim 2, comprising at least two types of periodic structures selected from the group consisting of: 　 The organic electroluminescence device according to claim 1 , wherein the organic portion has at least two layers each having a periodic uneven shape.

2. The organic electroluminescence element according to claim 1, further comprising a structure having a periodic uneven shape, and the organic part is laminated on a surface of the structure having the uneven shape. 　 The organic electroluminescence device according to claim 1 , wherein the organic portion has an organic layer formed on a flat surface.

2. The organic electroluminescence device according to claim 1, wherein the organic part has at least one organic layer, and all of the organic layers constituting the organic part contain an organic semiconductor material. 　 The organic electroluminescence device according to claim 1 , wherein the organic portion includes at least an electrode. 　 The organic electroluminescent device according to claim 1 , wherein the light-emitting layer comprises a laser oscillation material.

2. The organic electroluminescence element according to claim 1, wherein the organic portion comprises a first organic layer and a second organic layer adjacent to the first organic layer and having a refractive index different from that of the first organic layer.

2. The organic electroluminescence element according to claim 1, wherein the organic portion has an adjacent layer adjacent to the light-emitting layer on at least one of the hole injection portion side and the electron injection portion side of the light-emitting layer, and the adjacent layer has a refractive index different from that of the light-emitting layer.

2. The organic electroluminescence device according to claim 1, wherein the organic electroluminescence device is an organic solid-state semiconductor laser. 　 a hole injection unit that injects holes; an electron injection unit that injects electrons; an organic portion disposed between the hole injection portion and the electron injection portion; Equipped with the organic portion includes a light-emitting layer that recombines holes and electrons to emit light, A method for controlling an emission wavelength of an organic electroluminescence element having a refractive index periodic structure in which a refractive index changes periodically in a predetermined direction in a cross section taken along a direction perpendicular to a thickness direction of the organic part, comprising: A method for controlling the emission wavelength of an organic electroluminescence element by setting the period of the refractive index periodic structure. 　 the refractive index periodic structure has a periodic structure in which first regions and second regions having a refractive index different from that of the first regions are alternately arranged in a predetermined direction, The calculation means calculates λ based on the Bragg equation: Ｂｒａｇｇ and Λ ｍ A process of determining the relationship between ខ្រានក Ｂｒａｇｇ =2. ｅｆｆ L ｍ [where m is the diffraction order, λ Ｂｒａｇｇ is the Bragg wavelength, n ｅｆｆ is the effective refractive index of one of the first and second regions, Λ ｍ represents the pitch of the refractive index periodic structure.] The pitch determining means determines the λ determined by the calculating means. Ｂｒａｇｇ and Λ ｍ In the relationship, λ Ｂｒａｇｇ is the desired emission wavelength, and this λ Ｂｒａｇｇ Λ corresponding to ｍ Select the selected Λ ｍ and determining the period of the refractive index periodic structure as the pitch of the refractive index periodic structure. 　 To implement the method of claim 22, a computer is configured to: a program that causes the calculation means and the pitch determination means to function; 　 A computer-readable recording medium on which the program according to claim 23 is recorded. 　 a hole injection unit that injects holes; an electron injection unit that injects electrons; a light-emitting layer that recombines holes and electrons to emit light; Equipped with A method for controlling light extraction characteristics of an organic electroluminescence element, in which light generated in the light-emitting layer propagates laterally through the light-emitting layer and is extracted from a light extraction surface, comprising: The method comprises providing a recombination concentration portion laterally along the light-emitting layer. 　 An organic electroluminescence device having controlled light extraction characteristics, produced by carrying out the method according to claim 25. 　 a hole injection unit that injects holes; an electron injection unit that injects electrons; a light-emitting layer disposed between the hole injection section and the electron injection section, which recombines holes and electrons to emit light; an optical resonator that propagates emitted light within the light-emitting layer; Equipped with An organic electroluminescence element in which light is extracted from a light extraction surface, a hole blocking layer is provided adjacent to the light emitting layer on the electron injection portion side of the light emitting layer; an electron blocking layer adjacent to the light-emitting layer on the hole injection section side of the light-emitting layer; and An organic electroluminescence element comprising a control member for controlling light extraction characteristics.

1. A display device having a plurality of pixels, 28. A display device, wherein the plurality of pixels comprise the organic electroluminescent device according to claim 27. 　 a hole injection unit that injects holes; an electron injection unit that injects electrons; an organic portion disposed between the hole injection portion and the electron injection portion; Equipped with An organic electroluminescence element, wherein the organic portion includes a light-emitting layer that recombines holes and electrons to emit light, an organic electroluminescence element in which, when a voltage is applied between the hole injection section and the electron injection section, at least one of an electric field intensity periodic structure in which the electric field intensity changes periodically in a predetermined direction and a current intensity periodic structure in which the current intensity changes periodically in a predetermined direction is formed between the hole injection section and the electron injection section in a cross section taken along a direction perpendicular to a thickness direction of the organic section, and light from the light-emitting layer resonates in the electric field intensity periodic structure or the current intensity periodic structure.

30. The organic electroluminescence element according to claim 29, wherein at least one of the hole injection section and the electron injection section includes an electrode layer having a conductive periodic structure whose conductivity changes periodically in a predetermined direction, and the electric field intensity periodic structure is formed with a period corresponding to the period of the conductive periodic structure.

31. The organic electroluminescence device according to claim 30, wherein the current intensity periodic structure is formed with a period corresponding to the period of the conductive periodic structure.

30. The organic electroluminescence element according to claim 29, wherein the organic portion includes an organic layer having a conductive periodic structure whose conductivity changes periodically in a predetermined direction, and the current intensity periodic structure is formed with a period corresponding to the period of the conductive periodic structure.

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