Light-emitting element, display device, electronic device, and lighting device

Abstract

To provide a light emitting element that has high luminous efficiency and operates at a low voltage.SOLUTION: A light emitting element includes a guest material and a host material. The LUMO level of the guest material is higher than the LUMO level of the host material, and the HOMO level of the guest material is lower than the HOMO level of the host material. The guest material has a function of converting triplet excitation energy into light emission. The host material has a difference between the singlet excitation energy level and the triplet excitation energy level of more than 0 eV and 0.2 eV or less, and the energy difference between the LUMO level and the HOMO level of the host material is equal to or greater than the light emission energy exhibited by the guest material.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] One embodiment of the present invention is a light-emitting element, or a display device, an electronic device, and a lighting device each having the light-emitting element. Regarding the lighting device.

[0002] Note that one embodiment of the present invention is not limited to the above technical fields. The technical field of one aspect of the present invention relates to an article, a method, or a manufacturing method. is a process, machine, manufacture, or composition of matter. Therefore, the technical field of one embodiment of the present invention disclosed in this specification more specifically relates to Examples of the semiconductor device include a semiconductor device, a display device, a liquid crystal display device, a light-emitting device, a lighting device, a power storage device, a memory device, and the like. Examples include devices, methods for driving them, and methods for manufacturing them. . [Background technology]

[0003] In recent years, electroluminescence (EL) The basic structure of these light-emitting devices is as follows: The device has a structure in which a layer containing a light-emitting material (EL layer) is sandwiched between a pair of electrodes. By applying a voltage across the material, light is emitted from the luminescent material.

[0004] Since the above-mentioned light-emitting element is a self-luminous type, a display device using it has excellent visibility and It has the advantage of not requiring a light source and consuming little power. It also has the advantage of high response speed.

[0005] An organic material is used as the light-emitting material, and an EL layer containing the light-emitting material is provided between a pair of electrodes. In the case of a light-emitting element (for example, an organic EL element), by applying a voltage between a pair of electrodes, Electrons are injected from the cathode and holes are injected from the anode into the EL layer, generating a current. The injected electrons and holes are recombined to form a light-emitting organic material. is excited, and light can be emitted from the excited light-emitting organic material.

[0006] The types of excited states that organic materials can form include singlet excited states (S * ) and triplet excited states state(T * ) emission from the singlet excited state is fluorescence, and emission from the triplet excited state is phosphorescence. The statistical generation ratio of these in a light-emitting element is called S * :T * =1 :3. Therefore, it is more effective to use a light-emitting element that emits phosphorescence than a light-emitting element that uses a material that emits fluorescence (fluorescent material). Therefore, a light-emitting element using a material that emits light (phosphorescent material) can have higher luminous efficiency. Therefore, phosphorescent materials capable of converting triplet excited state energy into luminescence are used. In recent years, development of light-emitting devices has been actively pursued (see, for example, Patent Document 1).

[0007] The energy required to excite an organic material depends on the LUMO and HOMO levels of the organic material. Since it depends on the energy difference with the position, it roughly corresponds to the energy of the singlet excited state. In a light-emitting element using an organic material that emits light, triplet excitation energy is the energy of light emission. Therefore, the singlet excited state and triplet excited state formed by organic materials are When the energy difference is large, the energy required to excite the organic material is The energy of the light emitted is higher than that of the light emitted by the organic material by the amount of energy equivalent to the energy difference. The difference between the energy required to generate light and the energy required to emit light is the driving voltage of the light-emitting element. Therefore, methods for reducing the driving voltage have been developed. Development is currently underway (see Patent Document 2).

[0008] Furthermore, among light-emitting elements using phosphorescent materials, light-emitting elements that emit blue light are However, due to the difficulty in developing stable organic materials with high triplet excitation energy levels, Therefore, stable organic materials with high triplet excitation energy levels have not yet been put to practical use. There is a need to develop phosphorescent light-emitting materials that are highly reliable and have high luminous efficiency. Child development is required. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-182699 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-212879 Summary of the Invention [Problem to be solved by the invention]

[0010] Iridium complexes are known as phosphorescent materials that exhibit high luminous efficiency. As an energetic iridium complex, we have developed an iridium complex having a nitrogen-containing five-membered heterocyclic skeleton as a ligand. The nitrogen-containing five-membered heterocyclic skeleton has a high triplet excitation energy. However, compared to the nitrogen-containing six-membered heterocyclic skeleton, it has a lower electron-accepting property. Iridium complexes with ring structures as ligands have high LUMO levels and electron carriers are injected. In this way, in iridium complexes with high emission energy, It is difficult to excite the ions by direct recombination, making it difficult to emit light efficiently.

[0011] Therefore, in one embodiment of the present invention, a light-emitting element including a phosphorescent material has high emission efficiency. Another object of one embodiment of the present invention is to provide a light-emitting element having low power consumption. Another object of the present invention is to provide a light-emitting element with reduced signal loss. Another object of the present invention is to provide a light-emitting element with excellent reliability. Another object of the present invention is to provide a novel light-emitting element. Another object of the present invention is to provide a light-emitting device. One of the objectives is to provide a facility for

[0012] Note that the above description of the object does not preclude the existence of other objects. It is not necessary to solve all of these problems. Problems other than those mentioned above can be solved by the description of the specification, etc. It is obvious from the description of the specification, etc. that other problems can be extracted. do. [Means for solving the problem]

[0013] One embodiment of the present invention is a method for efficiently exciting a phosphorescent material having high emission energy. The light-emitting element has a host material that can

[0014] Therefore, one embodiment of the present invention is a light-emitting element having a first material and a second material. Therefore, the energy difference between the LUMO level and the HOMO level of the first material is The first material has a triplet excitation energy greater than the energy difference between the MO level and the HOMO level. It is a light-emitting element that has the function of converting energy into light.

[0015] Another embodiment of the present invention is a light-emitting element including a first material and a second material. The LUMO level of the first material is higher than the LUMO level of the second material, and the H The OMO level is lower than the HOMO level of the second material, and the first material has triplet excitation energy It is a light-emitting element that has the function of converting light into light.

[0016] Another embodiment of the present invention is a light-emitting element including a first material and a second material. The LUMO level of the first material is equal to the LUMO level of the second material, and the first material The HOMO level of the first material is lower than the HOMO level of the second material, and the first material has triplet excited energy. It is a light-emitting element that has the function of converting energy into light.

[0017] Another embodiment of the present invention is a light-emitting element including a first material and a second material. The LUMO level of the first material is higher than the LUMO level of the second material, and the H The OMO level is equal to the HOMO level of the second material, and the first material has triplet excitation energy. It is a light-emitting element that has the function of converting energy into light.

[0018] Another embodiment of the present invention is a light-emitting element including a first material and a second material. The energy difference between the LUMO level and the HOMO level of the first material is The first material has a triplet excitation energy greater than the energy difference between the O level and the HOMO level. The second material has the function of converting the singlet excited energy level into light emission. and the triplet excitation energy level is greater than 0 eV and not more than 0.2 eV. is.

[0019] Another embodiment of the present invention is a light-emitting element including a first material and a second material. The LUMO level of the first material is higher than the LUMO level of the second material, and the H The OMO level is lower than the HOMO level of the second material, and the first material has triplet excitation energy The second material has the function of converting the singlet excited energy level into light emission. and the triplet excitation energy level is greater than 0 eV and not more than 0.2 eV. is.

[0020] Another embodiment of the present invention is a light-emitting element including a first material and a second material. The LUMO level of the first material is equal to the LUMO level of the second material, and the first material The HOMO level of the first material is lower than the HOMO level of the second material, and the first material has triplet excited energy. The second material has the function of converting singlet excitation energy into light. The difference between the energy level and the triplet excited energy level is greater than 0 eV and 0.2 eV or less. It is an element.

[0021] Another embodiment of the present invention is a light-emitting element including a first material and a second material. The LUMO level of the first material is higher than the LUMO level of the second material, and the H The OMO level is equal to the HOMO level of the second material, and the first material has triplet excitation energy. The second material has the function of converting singlet excitation energy into light. The difference between the energy level and the triplet excited energy level is greater than 0 eV and 0.2 eV or less. It is an element.

[0022] Another aspect of the present invention is a method for manufacturing a semiconductor device having a first material, a second material, and a third material. a light-emitting element, wherein the energy difference between the LUMO level and the HOMO level of the third material is the energy difference between the LUMO level and the HOMO level of the first material is greater than the energy difference between the LUMO level and the HOMO level of the second material. The energy difference between the LUMO level and the HOMO level of the second material is and the first material converts the triplet excitation energy into luminescence. It is a light-emitting element having the function of being able to

[0023] Another aspect of the present invention is a method for manufacturing a semiconductor device having a first material, a second material, and a third material. a light-emitting device, wherein the LUMO level of the third material is higher than the LUMO level of the second material; The HOMO level of the third material is lower than the HOMO level of the second material, and the LUM of the first material The O level of the first material is higher than the LUMO level of the second material, and the HOMO level of the first material is higher than the LUMO level of the second material. The first material has a lower HOMO level than the first material, and the second material converts triplet excitation energy into light emission. It is a light-emitting element having the function of being able to

[0024] Another aspect of the present invention is a method for manufacturing a semiconductor device having a first material, a second material, and a third material. a light-emitting device, wherein the LUMO level of the third material is higher than the LUMO level of the second material; The HOMO level of the third material is lower than the HOMO level of the second material, and the LUM of the first material The O level is equivalent to the LUMO level of the second material, and the HOMO level of the first material is equivalent to the LUMO level of the second material. the HOMO level of the first material is lower than the HOMO level of the second material, and the first material converts triplet excitation energy into luminescence. It is a light-emitting element having a function of being able to

[0025] Another aspect of the present invention is a method for manufacturing a semiconductor device having a first material, a second material, and a third material. a light-emitting device, wherein the LUMO level of the third material is higher than the LUMO level of the second material; The HOMO level of the third material is lower than the HOMO level of the second material, and the LUM of the first material The O level of the first material is higher than the LUMO level of the second material, and the HOMO level of the first material is higher than the LUMO level of the second material. The first material converts triplet excitation energy into light emission. It is a light-emitting element having a function of being able to

[0026] Another aspect of the present invention is a method for manufacturing a semiconductor device having a first material, a second material, and a third material. a light-emitting element, wherein the energy difference between the LUMO level and the HOMO level of the third material is the energy difference between the LUMO level and the HOMO level of the first material is greater than the energy difference between the LUMO level and the HOMO level of the second material. The energy difference between the LUMO level and the HOMO level of the second material is and the first material converts the triplet excitation energy into luminescence. The second material has a function of being able to change the singlet excitation energy level and the triplet excitation energy level. The difference between the energy level and the energy level is greater than 0 eV and 0.2 eV or less.

[0027] Another aspect of the present invention is a method for manufacturing a semiconductor device having a first material, a second material, and a third material. a light-emitting device, wherein the LUMO level of the third material is higher than the LUMO level of the second material; The HOMO level of the third material is lower than the HOMO level of the second material, and the LUM of the first material The O level of the first material is higher than the LUMO level of the second material, and the HOMO level of the first material is higher than the LUMO level of the second material. The first material has a lower HOMO level than the first material, and the second material converts triplet excitation energy into light emission. The second material has a function of being able to change the singlet excitation energy level and the triplet excitation energy level. The difference between the energy level and the energy level is greater than 0 eV and 0.2 eV or less.

[0028] Another aspect of the present invention is a method for manufacturing a semiconductor device having a first material, a second material, and a third material. a light-emitting device, wherein the LUMO level of the third material is higher than the LUMO level of the second material; The HOMO level of the third material is lower than the HOMO level of the second material, and the LUM of the first material The O level is equivalent to the LUMO level of the second material, and the HOMO level of the first material is equivalent to the LUMO level of the second material. the HOMO level of the first material is lower than the HOMO level of the second material, and the first material converts triplet excitation energy into luminescence. The second material has a function of being able to change the singlet excited energy level and the triplet excited energy level. The difference between the energy level and the energy level is greater than 0 eV and not more than 0.2 eV.

[0029] Another aspect of the present invention is a method for manufacturing a semiconductor device having a first material, a second material, and a third material. a light-emitting device, wherein the LUMO level of the third material is higher than the LUMO level of the second material; The HOMO level of the third material is lower than the HOMO level of the second material, and the LUM of the first material The O level of the first material is higher than the LUMO level of the second material, and the HOMO level of the first material is higher than the LUMO level of the second material. The first material converts triplet excitation energy into light emission. The second material has a function of being able to change the singlet excited energy level and the triplet excited energy level. The difference between the energy level and the energy level is greater than 0 eV and not more than 0.2 eV.

[0030] In each of the above structures, the energy between the LUMO level and the HOMO level of the second material is The difference is equal to or greater than the transition energy calculated from the absorption edge in the absorption spectrum of the first material. In addition, the energy difference between the LUMO level and the HOMO level of the first material is preferably From the transition energy calculated from the absorption edge in the absorption spectrum of the first material, 0.4 It is preferable that it is larger than eV.

[0031] In each of the above structures, the energy between the LUMO level and the HOMO level of the second material is The difference is preferably equal to or greater than the energy of the light emitted by the first material. The energy difference between the LUMO level and the HOMO level is the energy of the light emitted by the first material. Therefore, it is preferable that the difference is 0.4 eV or more.

[0032] In each of the above structures, the second material has a function of exhibiting thermally activated delayed fluorescence at room temperature. This is preferable.

[0033] In each of the above structures, the second material has a function of providing excitation energy to the first material. In addition, it is preferable that the emission spectrum of the second material has the absorption spectrum of the first material. It is preferable that the absorption band has a region overlapping with the absorption band on the longest wavelength side of the spectrum.

[0034] In each of the above structures, the first material preferably contains iridium. Preferably, the material in 1 exhibits luminescence.

[0035] In each of the above structures, the second material has a function of transporting electrons, The second material preferably has a function of transporting holes. The first material has a π-electron deficient heteroaromatic ring skeleton, and the second material has a π-electron rich heteroaromatic ring skeleton or It is preferable that the compound has at least one of an aromatic amine skeleton and an aromatic amine skeleton.

[0036] In the above structure, the π-electron-deficient heteroaromatic ring skeleton is a diazine skeleton or a triazine skeleton. The π-electron-rich heteroaromatic ring skeleton is an acridine skeleton, a fluorine skeleton, or a fluorine skeleton. Phenoxazine skeleton, phenothiazine skeleton, furan skeleton, thiophene skeleton, and pyrrole skeleton It is preferable that the compound has one or more selected from the group consisting of a pyrrole skeleton and a pyrrole skeleton. is an indole skeleton, a carbazole skeleton, or a 3-(9-phenyl-9H-carbazole) It is preferable that the compound has a (9H-carbazole)-3-yl)-9H-carbazole skeleton.

[0037] Another embodiment of the present invention is a light-emitting element having any of the above structures, a color filter or a transistor, and a light-emitting element. and at least one of a first transistor and a second transistor. The electronic device includes the display device and at least one of a housing and a touch sensor. Another embodiment of the present invention is a light-emitting element having any of the above structures, a housing, or a touch sensor. Another embodiment of the present invention is a lighting device having a light-emitting element. Not only optical devices but also electronic devices having light-emitting devices are included in the category. The light-emitting device in this context refers to an image display device or a light source (including a lighting device). Connectors for optical devices, such as FPC (Flexible Printed Circuit) t), TCP (Tape Carrier Package) mounted module modules with printed wiring boards at the end of TCP, or COG (C There are also modules with ICs (integrated circuits) directly mounted using the "hip on glass" method. It may include a light emitting device. [Effects of the Invention]

[0038] According to one embodiment of the present invention, a light-emitting element including a phosphorescent material has high emission efficiency. According to one embodiment of the present invention, a light-emitting element with reduced power consumption can be provided. According to one embodiment of the present invention, a highly reliable light-emitting element can be provided. Alternatively, according to one embodiment of the present invention, a novel light-emitting element can be provided. According to one embodiment of the present invention, a novel light-emitting device can be provided. Furthermore, according to one embodiment of the present invention, a novel display device can be provided.

[0039] The description of these effects does not preclude the existence of other effects. It is not necessary to have all of these effects. Effects other than these may be included in the description. It is obvious from the description of the specification, drawings, claims, etc. From this, it is possible to extract other effects. [Brief explanation of the drawings]

[0040] [Figure 1] 1A and 1B are schematic cross-sectional views of a light-emitting element according to one embodiment of the present invention. [Figure 2] 1A and 1B are diagrams illustrating the correlation between energy levels and the correlation between energy bands in a light-emitting layer of a light-emitting element according to one embodiment of the present invention. [Figure 3] 1A and 1B are schematic cross-sectional views of a light-emitting element according to one embodiment of the present invention. [Figure 4] 1A and 1B are diagrams illustrating the correlation between energy levels and the correlation between energy bands in a light-emitting layer of a light-emitting element according to one embodiment of the present invention. [Figure 5] 1A and 1B are schematic cross-sectional views of a light-emitting element of one embodiment of the present invention and a diagram illustrating the correlation between energy levels; [Figure 6] 1A and 1B are schematic cross-sectional views of a light-emitting element according to one embodiment of the present invention. [Figure 7] 1A and 1B are schematic cross-sectional views of a light-emitting element according to one embodiment of the present invention. [Figure 8] 1A to 1C are schematic cross-sectional views illustrating a method for manufacturing a light-emitting element according to one embodiment of the present invention. [Figure 9] 1A to 1C are schematic cross-sectional views illustrating a method for manufacturing a light-emitting element according to one embodiment of the present invention [Figure 10] 1A and 1B are a top view and a cross-sectional view schematic diagram illustrating a display device of one embodiment of the present invention. [Figure 11] 1A and 1B are schematic cross-sectional views illustrating a display device according to one embodiment of the present invention. [Figure 12] 1A and 1B are schematic cross-sectional views illustrating a display device according to one embodiment of the present invention. [Figure 13] 1A and 1B are schematic cross-sectional views illustrating a display device according to one embodiment of the present invention. [Figure 14] 1A and 1B are schematic cross-sectional views illustrating a display device according to one embodiment of the present invention. [Figure 15] 1A and 1B are schematic cross-sectional views illustrating a display device according to one embodiment of the present invention. [Figure 16] 1A and 1B are schematic cross-sectional views illustrating a display device according to one embodiment of the present invention. [Figure 17] 1A and 1B are schematic cross-sectional views illustrating a display device according to one embodiment of the present invention. [Figure 18] 1A and 1B are schematic cross-sectional views illustrating a display device according to one embodiment of the present invention. [Figure 19] 1A and 1B are a block diagram and a circuit diagram illustrating a display device of one embodiment of the present invention. [Figure 20] FIG. 1 is a circuit diagram illustrating a pixel circuit of a display device according to one embodiment of the present invention. [Figure 21] FIG. 1 is a circuit diagram illustrating a pixel circuit of a display device according to one embodiment of the present invention. [Figure 22] FIG. 1 is a perspective view illustrating an example of a touch panel of one embodiment of the present invention. [Figure 23] 1A and 1B are cross-sectional views illustrating examples of a display device and a touch sensor according to one embodiment of the present invention. [Figure 24] FIG. 1 is a cross-sectional view illustrating an example of a touch panel of one embodiment of the present invention. [Figure 25] 1A and 1B are a block diagram and a timing chart of a touch sensor according to one embodiment of the present invention. [Figure 26] FIG. 1 is a circuit diagram of a touch sensor according to one embodiment of the present invention. [Figure 27]FIG. 1 is a perspective view illustrating a display module of one embodiment of the present invention. [Figure 28] 1A to 1C illustrate electronic devices of one embodiment of the present invention. [Figure 29] 1A to 1C illustrate electronic devices of one embodiment of the present invention. [Figure 30] 1A to 1C illustrate electronic devices of one embodiment of the present invention. [Figure 31] FIG. 1 is a perspective view illustrating a display device according to one embodiment of the present invention. [Figure 32] 1A and 1B are a perspective view and a cross-sectional view illustrating a light-emitting device according to one embodiment of the present invention [Figure 33] FIG. 1 is a cross-sectional view illustrating a light-emitting device according to one embodiment of the present invention. [Figure 34] 1A to 1C illustrate a lighting device and an electronic device according to one embodiment of the present invention. [Figure 35] 1A to 1C illustrate a lighting device according to one embodiment of the present invention. [Figure 36] 1A and 1B are cross-sectional views illustrating a light-emitting element according to an embodiment. [Figure 37] FIG. 10 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 38] FIG. 10 is a graph showing luminance-voltage characteristics of a light-emitting element according to an example. [Figure 39] FIG. 10 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 40] FIG. 10 is a graph showing power efficiency vs. luminance characteristics of a light-emitting element according to an embodiment. [Figure 41] 10A and 10B are graphs illustrating electroluminescence spectra of light-emitting elements according to Examples. [Figure 42] FIG. 1 is a diagram illustrating an emission spectrum of a host material according to an example. [Figure 43] FIG. 10 is a diagram illustrating transient fluorescence characteristics of a host material according to an example. [Figure 44] FIG. 10 is a graph showing current efficiency-luminance characteristics of a comparative light-emitting element according to an example. [Figure 45] FIG. 10 is a graph showing luminance-voltage characteristics of a comparative light-emitting element according to an example. [Figure 46]FIG. 10 is a graph showing external quantum efficiency-luminance characteristics of a comparative light-emitting element according to an example. [Figure 47] FIG. 10 is a graph showing power efficiency vs. luminance characteristics of a comparative light-emitting element according to an example. [Figure 48] FIG. 10 is a graph showing electroluminescence spectra of comparative light-emitting elements according to examples. [Figure 49] 4A and 4B are diagrams illustrating absorption spectra and emission spectra of guest materials according to an example. [Figure 50] FIG. 10 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 51] FIG. 10 is a graph showing luminance-voltage characteristics of a light-emitting element according to an example. [Figure 52] FIG. 10 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 53] FIG. 10 is a graph showing power efficiency vs. luminance characteristics of a light-emitting element according to an embodiment. [Figure 54] 10A and 10B are graphs illustrating electroluminescence spectra of light-emitting elements according to Examples. [Figure 55] FIG. 1 is a diagram illustrating an emission spectrum of a host material according to an example. [Figure 56] FIG. 4 is a diagram illustrating the absorption spectrum of a guest material according to an example. [Figure 57] FIG. 4 is a diagram illustrating the absorption spectrum of a guest material according to an example. DETAILED DESCRIPTION OF THE INVENTION

[0041] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the above description, and the embodiments and details thereof may be modified without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited to the embodiments described below. The terms and conditions of the present invention are not to be construed as being limited to the content.

[0042] In addition, the position, size, range, etc. of each component shown in the drawings etc. are not necessarily shown in order to facilitate understanding. It may not represent the actual position, size, range, etc. Therefore, the disclosed invention The position, size, range, etc. are not necessarily limited to those disclosed in the drawings, etc.

[0043] In addition, in this specification, ordinal numbers such as 1st, 2nd, etc. are used for convenience, In some cases, the order of processes or layers may not be indicated. For example, "first" may be replaced with "second" or " can be appropriately replaced with "third" etc. The ordinal numbers used to identify an aspect of the present invention may not match. be.

[0044] In addition, in this specification and the like, when explaining the configuration of the invention using drawings, the same The reference numerals may be commonly used even among different drawings.

[0045] In addition, in this specification and the like, the terms "film" and "layer" are interchangeable. For example, the term "conductive layer" can be changed to the term "conductive film." Alternatively, for example, the term "insulating film" may be changed to "insulating layer" It may be possible to change the term to

[0046] In this specification and the like, the singlet excited state (S * ) is a single atom with excitation energy The S1 level is the lowest singlet excited energy level. The lowest excited energy level is the singlet excited state. (T * ) is a triplet state with excitation energy. The lowest excited energy level of the triplet excited state is In this specification and the like, the singlet excited state and the singlet excited energy are simply referred to as the singlet excited state and the singlet excited energy. Even when written as an energy level, it refers to the lowest singlet excited state and the S1 level. In addition, when written as triplet excited state and triplet excited energy level, However, it may represent the lowest triplet excited state and the T1 level.

[0047] In this specification and the like, the fluorescent material refers to a material that emits light when it relaxes from a singlet excited state to a ground state. On the other hand, phosphorescent materials are materials that emit light in the visible light region from the triplet excited state to the ground state. When the material relaxes to the phosphorus state, it emits light in the visible light region at room temperature. An optical material is one of materials that can convert triplet excitation energy into visible light.

[0048] The phosphorescence energy or triplet excitation energy is the shortest wavelength side of the phosphorescence emission. It can be derived from the wavelength of the emission peak (including the shoulder) or the onset. The phosphorescence is observed by time-resolved photoluminescence in a low-temperature (e.g., 10 K) environment. The emission energy of thermally activated delayed fluorescence is , the shortest wavelength emission peak (including shoulder) or rising edge of thermally activated delayed fluorescence can be derived from the wavelength of

[0049] In this specification, room temperature refers to a temperature between 0°C and 40°C.

[0050] In this specification, the blue wavelength region refers to wavelengths of 400 nm or more and less than 505 nm. blue emission has at least one emission spectrum peak in this region. The green wavelength range is the wavelength range from 505 nm to less than 580 nm. Green emission is emission having at least one emission spectrum peak in this region. The red wavelength range is the wavelength range between 580 nm and 680 nm. The emission is an emission having at least one emission spectrum peak in the region.

[0051] (Embodiment 1) In this embodiment, a light-emitting element of one embodiment of the present invention will be described below with reference to FIGS. Reveal.

[0052] <Configuration example 1 of light-emitting element> First, the structure of a light-emitting element of one embodiment of the present invention will be described with reference to FIGS. This is explained below.

[0053] FIG. 1A is a schematic cross-sectional view of a light-emitting element 150 of one embodiment of the present invention.

[0054] The light emitting element 150 has a pair of electrodes (electrode 101 and electrode 102), and The EL layer 100 has at least a light-emitting layer 130. .

[0055] The EL layer 100 shown in FIG. 1A includes a hole injection layer 111, a positive electrode layer 112, a positive electrode layer 113, a positive electrode layer 114, a positive electrode layer 115, a positive electrode layer 116, a positive electrode layer 117, a positive electrode layer 118, a positive electrode layer 119 ... It has functional layers such as a hole transport layer 112, an electron transport layer 118, and an electron injection layer 119.

[0056] In this embodiment, of the pair of electrodes, electrode 101 is an anode, and electrode 1 Although the description will be given assuming that O2 is a cathode, the configuration of the light emitting element 150 is not limited to this. The electrode 101 is the cathode, the electrode 102 is the anode, and the layers between the electrodes are stacked in the reverse order. That is, from the anode side, the hole injection layer 111, the hole transport layer 112, and the light emitting layer 113 may be arranged in this order. The light-emitting layer 130, the electron transport layer 118, and the electron injection layer 119 may be stacked in this order. .

[0057] The configuration of the EL layer 100 is not limited to the configuration shown in FIG. 1(A). , a hole transport layer 112, an electron transport layer 118, and an electron injection layer 119. Alternatively, the EL layer 100 may be configured to have either a hole or electron injection layer. Reduce the barrier, improve the transportability of holes or electrons, or inhibit the transportability of holes or electrons or suppressing the quenching phenomenon caused by the electrode. The functional layers may each be a single layer or may be a laminate of multiple layers. It may be composed of

[0058] FIG. 1(B) is a cross-sectional view showing an example of the light-emitting layer 130 shown in FIG. 1(A). The light-emitting layer 130 shown in B) contains at least a guest material 131 and a host material 132. The guest material 131 has the function of converting triplet excitation energy into luminescence. Preferably, the first material is the host material 132 and the second material is the host material 132 .

[0059] In the light-emitting layer 130, the host material 132 is present in the largest amount by weight, and the guest material 131 is dispersed in a host material 132 .

[0060] Furthermore, a light-emitting organic material may be used as the guest material 131. The material is preferably one that has the function of converting triplet excitation energy into luminescence. It is particularly preferable that the material is a material that can emit phosphorescence (hereinafter also referred to as a phosphorescent material). In the following description, a configuration in which a phosphorescent material is used as the guest material 131 will be described. Therefore, the guest material 131 may be interpreted as a phosphorescent material.

[0061] <Light-emitting mechanism of light-emitting element 1> Next, the light emitting mechanism of the light emitting layer 130 will be described below.

[0062] In the light-emitting element 150 of one embodiment of the present invention, a pair of electrodes (electrode 101 and electrode 102) By applying a voltage between the cathode and the anode, electrons and holes are emitted from the cathode and the anode, respectively. The electrons and holes are then injected into the EL layer 100, causing a current to flow. As a result, the guest material 131 in the light-emitting layer 130 of the EL layer 100 is excited. The excited guest material 131 emits light.

[0063] Light emission from the guest material 131 is obtained through the following two processes. ·(α) Direct recombination process (β) Energy transfer process

[0064] ≪(α) Direct recombination process≫ First, the direct recombination process in the guest material 131 will be described. The electrons (holes) recombine in the guest material 131, forming an excited state of the guest material 131. In this case, the required excitation energy for the guest material 131 by the direct recombination process of carriers is The energy is determined by the lowest unoccupied molecular orbital (LOUNC) of the guest material. Molecular Orbital (LUMO) levels and the highest occupied molecular orbital (Hi Highest Occupied Molecular Orbital (HOMO) It corresponds to the energy difference between the 2-level and the 3-level, and roughly corresponds to the energy of the singlet excited state. Since the guest material 131 is a phosphorescent material, the energy of the triplet excited state is converted into light emission. Therefore, the guest material 131 forms an excited state in a singlet excited state and a excited state in a triplet excited state. When the energy difference is large, the energy required to excite the guest material 131 is The energy of the emitted light is higher by the amount of energy corresponding to the energy difference.

[0065] The energy required to excite the guest material 131 and the energy of the emission The energy difference affects the element characteristics as a difference in the driving voltage of the light emitting element. α) In the direct recombination process, the light emission starting voltage of the light emitting device is The voltage becomes larger than the voltage corresponding to the energy of light emission.

[0066] In addition, when the guest material 131 has high emission energy, the LU of the guest material 131 Because the MO level is high, it becomes difficult for electrons, which are carriers, to be injected into the guest material 131. , direct recombination of carriers (electrons and holes) in the guest material 131 becomes difficult. Therefore, it is difficult to obtain high luminous efficiency in the light-emitting element.

[0067] <(β) Energy transfer process> Next, to explain the energy transfer process between the host material 132 and the guest material 131, FIG. 2(A) shows a schematic diagram for explaining the correlation of energy levels. The notations and symbols are as follows: Guest (131): Guest material 131 (phosphorescent material) Host (132): Host material 132 ·S PG: S1 level of guest material 131 (phosphorescent material) T PG : T1 level of guest material 131 (phosphorescent material) ·S PH : S1 level of the host material 132 T PH : T1 level of the host material 132

[0068] The carriers recombine in the host material 132, and the host material 132 reaches a singlet excited state. When a triplet excited state is formed, the following two states are shown in Route E1 and Route E2 of FIG. 2(A). Thus, both the singlet excitation energy and the triplet excitation energy of the host material 132 are T1 level (T PG ), and the guest material 131 transitions to a triplet excited state. The guest material 131 in the triplet excited state emits phosphorescence.

[0069] The S1 level (S PH ) and T1 level (T PH ) are both T1 level (T PG ) or higher. By correlating the singlet excitation energy and triplet excitation energy of the resulting host material 132, The photovoltaic energy is calculated by the S level (S PH ) and T1 level (T PH )from T1 level (T PG ) can efficiently transfer energy to

[0070] In other words, in the light-emitting layer 130, excitation energy from the host material 132 to the guest material 131 is Energy is provided.

[0071] In addition, when the light-emitting layer 130 contains a material other than the host material 132 and the guest material 131, In this case, the light-emitting layer 130 is at the T1 level (T PH ) higher T1 It is preferable that the host material 132 has a triplet excitation level. Energy quenching is less likely to occur, and energy transfer to the guest material 131 is more efficient. occurs.

[0072] In addition, the singlet excitation energy of the host material 132 is higher than the T1 level (T P G ) in the host material 132. Level (S PH ) and T1 level (T PH ) is preferably small.

[0073] In addition, as shown in the energy band diagram in Figure 2(B), the LUMO level of the guest material 131 The LUMO level is higher than the LUMO level of the host material 132 and lower than the HOMO level of the guest material 131. The HOMO level of the guest material 132 is preferably lower than the HOMO level of the host material 132. The energy difference between the LUMO level and the HOMO level of 131 (ΔE G ) is the host material 132 The energy difference between the LUMO level and the HOMO level (ΔE H ) is larger than this. By establishing an energy level relationship, the guest material 131 and the host material 132 form an exciplex. In FIG. 2(B), the reaction of Guest (131) represents the guest material 131, Host (132) represents the host material 132, and ΔE G Ha Ge represents the energy difference between the LUMO level and the HOMO level of the test material 131, and ΔE H is the host The notation and symbol representing the energy difference between the LUMO level and the HOMO level of material 132. .

[0074] The guest material 131 emits light with a short wavelength and high energy. To achieve this, the energy difference (ΔE G On the other hand, in order to reduce the driving voltage of the light emitting element 150, It is preferable that the host is excited with as small an excitation energy as possible. The excitation energy of the excited state formed by the material 132 is preferably small. The energy difference (ΔE H ) is small is preferable.

[0075] Since the guest material 131 is a phosphorescent light-emitting material, it emits triplet excitation energy. The triplet excited state has the function of being able to convert into the excited state. Therefore, the guest material 131 has a stable LUMO level and a stable HOMO level. The energy difference (ΔE G ) can emit light with lower energy than The energy difference between the LUMO level and the HOMO level of this guest material 131 (ΔE G ) but The energy difference (ΔE) between the LUMO and HOMO levels of the 132 H ) larger than Even in this case, the luminescence energy (abbreviated as ΔE Em ) or suck The transition energy (abbreviated as ΔE abs ) is Δ E HIf the excitation energy is equal to or smaller than the excitation energy of the host material 132, the gate This allows the transfer of excitation energy to the guest material 131, resulting in light emission from the guest material 131. The present inventors have found that the ΔE G However, the guest material The luminescence energy (ΔE Em ) or from the absorption edge in the absorption spectrum The calculated transition energy (ΔE abs ), the guest material 131 is directly charged. To excite the electrons, ΔE G A large amount of electrical energy equivalent to However, in one embodiment of the present invention, ΔE H (ΔE G (less than The host material 132 is electrically excited by electrical energy corresponding to The migration generates an excited state of the guest material 131, allowing for low driving voltage and high efficiency. Therefore, light can be emitted from the guest material 131. The voltage at which light emission begins (luminance is 1 cd / m 2 The guest material exhibits a voltage Luminous energy (ΔE Em ) can be made smaller than the voltage corresponding to Δ E G The luminescence energy (ΔE Em ) or absorption spectrum The transition energy (ΔE abs ) is much larger than ( For example, in the case where the guest material is a blue light-emitting material, one embodiment of the present invention is particularly beneficial. The energy of light emission (ΔE Em ) is the emission peak at the shortest wavelength side of the emission spectrum ( The wavelength of the peak (including the peak or shoulder) can be derived from the wavelength of the peak.

[0076] When the guest material 131 contains a heavy metal, spin-orbit interaction (electron spin angle Intersystem crossing between the singlet and triplet states is promoted by the interaction of the orbital angular momentum and the orbital angular momentum. Since the guest material 131 undergoes a transition between the singlet ground state and the triplet excited state, In other words, the singlet ground state and triplet excited state of the guest material 131 may be acceptable. The efficiency of light emission and the probability of absorption associated with the transition between the states can be increased. The guest material 131 preferably has a metal element with a large spin-orbit interaction, and in particular, Metal group elements (ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium ( It is preferable that the metal is iridium (Ir), iridium (Os), or platinum (Pt). The presence of rhodium enhances the absorption involved in the direct transition between the singlet ground state and the triplet excited state. This is preferable as it can increase the yield rate.

[0077] Here, for example, if the HOMO level of the guest material 131 is higher than the HOMO level of the host material 132, The material having the highest HOMO level among the materials contained in the light-emitting layer 130 is The material with the lowest LUMO level is the guest material 131, and the material with the lowest LUMO level is the host material 132. In this case, carriers (holes and Among the electrons injected from the cathode, the electrons are transferred to the host material 132 in the light-emitting layer 130. Therefore, holes injected from the anode are easily injected into the guest material 131. Therefore, the guest material 131 and the host material 132 may form an exciplex. In particular, the energy gap between the HOMO level of the guest material 131 and the LUMO level of the host material 132 is As the energy difference becomes smaller than the emission energy of the guest material 131, The formation of an exciplex formed between the material 131 and the host material 132 is dominant. Therefore, the guest material 131 is unlikely to generate an excited state by itself, resulting in a decrease in the luminous efficiency of the light-emitting element. It goes down.

[0078] In addition, the LUMO level of the guest material 131 is lower than the LUMO level of the host material 132. Therefore, among the materials contained in the light-emitting layer 130, the material having the lowest LUMO level is the guest material. material 131 and the material with the highest HOMO level is the host material 132. Carriers (holes and electrons) injected from the pair of electrodes (electrodes 101 and 102) Among them, the electrons injected from the cathode are easily injected into the guest material 131 in the light-emitting layer 130. Therefore, holes injected from the anode are easily injected into the host material 132. The guest material 131 and the host material 132 may form an exciplex. , the energy difference between the LUMO level of the guest material 131 and the HOMO level of the host material 132 becomes smaller than the emission energy of the guest material 131. In this case, the formation of an exciplex formed between the guest material 132 and the host material 132 is dominant. Since it becomes difficult for the material 131 alone to generate an excited state, the luminous efficiency of the light-emitting element decreases. cormorant.

[0079] However, in the light-emitting element of one embodiment of the present invention, the guest material 131 and the host material Since the reaction of forming an exciplex with the material 132 can be suppressed, high luminescence efficiency is exhibited. From this point of view, it is possible to fabricate a light-emitting device in which the guest material 131 The LUMO level of the host material 132 or the HOMO level of the guest material 131 The level and the HOMO level of the host material 132 may be the same, which is one aspect of the present invention. However, for the reasons described below, the LUMO level and HOMO level of the guest material 131 are The energy difference (ΔE G ) is the energy difference between the LUMO and HOMO levels of the host material 132. Energy difference (ΔE H ) is preferably larger than

[0080] That is, as described above, the LUMO level and the HOMO level of the guest material 131 The energy difference (ΔE G ) is the energy difference between the LUMO and HOMO levels of the host material 132. Energy difference (ΔE H ), calculated from the absorption edge of the guest material 131. The transition energy (ΔE abs ) is ΔE H If it is equal to or smaller than the host material 13 The excitation energy is efficiently transferred from the excited state formed by 2 to the guest material 131. As a result, one of the features of one embodiment of the present invention is that a light-emitting element can be obtained with low voltage and high efficiency. In this case, ΔE G >ΔE H ≧ΔE abs (ΔE G is ΔE H Larger, ΔE H is ΔE abs Therefore, the LUMO level and the HOMO level of the guest material 131 are The energy difference between the G ) is the transition energy calculated from the absorption edge of the guest material 131. Gee (ΔE abs), the mechanism of one aspect of the present invention is preferable. Specifically, the energy difference (ΔE G ) is the transition energy (ΔE abs ) and 0 It is preferable that the luminescence energy (Δ E Em ) is ΔE abs Since the LUMO of the guest material 131 is equal to or smaller than The energy difference between the HOMO level and the G ) is the source of the luminescence from the guest material 131. Energy (ΔE Em ) is preferably 0.4 eV or more larger.

[0081] In addition, the energy difference between the LUMO level and the HOMO level of the host material 132 (ΔE H )teeth , the S1 level of the host material 132 (S PH ) is equal to or slightly larger than the host material 132 S1 level (S PH ) is the T1 level (T PH ) is larger than the T1 Level (T PH ) is the T1 level (T PG ) or more. Therefore, Δ E G >ΔE H ≧S PH >T PH ≧T PG (ΔE G is ΔE H Larger, ΔE H is S PH Below Above, S PH is T PH Bigger, T PH is T PG (The above is the case.) In addition, the guest material The absorption at the absorption edge in the absorption spectrum of 131 is the singlet ground state of the guest material 131. If the absorption is due to a transition between the triplet excited state and the triplet excited state, ΔT PG is ΔE abs Is it equivalent to The energy is slightly smaller. Therefore, ΔE G is ΔE abs at least 0.4 eV In order to be larger than this, ΔE G and ΔE abs From the energy difference, S PH and T PH and The energy difference between S is preferably small. PH and T PH Energy difference between is preferably greater than 0 eV and less than or equal to 0.2 eV, more preferably greater than 0 eV and It is less than 0.1 eV.

[0082] The energy difference between the singlet and triplet excited energy levels is small, Suitable materials for the fluorescent material 132 include thermally activated delayed fluorescence (TDF). and TADF (Tatakamide-activated delayed fluorescence) materials. Thermally activated delayed fluorescent materials have an energy level between singlet and triplet excited states. The energy difference is small, and the triplet excitation energy is converted to the singlet excitation energy by reverse intersystem crossing. Note that the host material 132 according to one embodiment of the present invention has a function of being able to be converted into Therefore, it is not necessarily T PH From S PH The reverse intersystem crossing efficiency to S does not need to be high. PH from Since the luminescence quantum yield does not need to be high, a wide range of materials can be selected.

[0083] In addition, the energy difference between the singlet and triplet excited energy levels is reduced. To achieve this, the host material 132 should have a backbone having a hole transporting function (hole transporting property). and a skeleton having the function of transporting electrons (electron transport property). In this case, the excited state of the host material 132 is such that the HOMO molecular orbital is attached to the skeleton having hole transport properties. The electron-transporting skeleton has a LUMO molecular orbital, so the HOMO molecular orbital The overlap between the molecular orbital of the LUMO and the donor in a single molecule is extremely small. -Acceptor type excited states are more easily formed, and the singlet and triplet excited energy levels In the host material 132, the energy difference between the electron transport energy level and the electron transport energy level is small. Singlet excited energy level (S PH ) and triplet excited energy level (T PH ) is a good Preferably, it is greater than 0 eV and equal to or less than 0.2 eV.

[0084] The molecular orbital represents the spatial distribution of electrons in a molecule and can represent the probability of finding an electron. Molecular orbitals allow us to determine in detail the electron configuration of a molecule (the spatial distribution and energy of electrons). It is possible to describe in detail.

[0085] In addition, when the host material 132 has a skeleton with strong donor properties, the The holes are easily injected into the host material 132 and transported. When the host material has a skeleton with a strong acceptor property, the electrons injected into the light-emitting layer 130 are absorbed by the host material. Both holes and electrons are injected into the host material 132 and are easily transported. This is preferable because it makes it easier for the host material 132 to form an excited state.

[0086] The emission wavelength of the guest material 131 becomes shorter, and the emission energy (ΔEEm ) is large The larger the energy difference (ΔE G ) becomes large, and accordingly, a large amount of energy is required to directly electrically excite the guest material. However, in one embodiment of the present invention, the absorption of the guest material 131 is The transition energy (ΔE abs ) is ΔE H and If it is equal to or smaller, ΔE G ΔE is much smaller than H With energy of about Since the material 131 can be excited, the power consumption of the light-emitting element can be reduced. Therefore, the transition energy calculated from the absorption edge in the absorption spectrum of the guest material 131 is Gee (ΔE abs ) and the energy between the LUMO and HOMO levels of the guest material 131 Difference (ΔE G ) and the larger the energy difference between (i.e., blue light is emitted) In the case of a guest material, the effect of the mechanism of the present invention becomes significant.

[0087] However, the transition energy calculated from the absorption edge in the absorption spectrum of the guest material 131 is Gee (ΔE abs ) becomes smaller, the luminescence energy (ΔE Em ) also becomes smaller, making it difficult to obtain high-energy emission such as blue light. In other words, it becomes difficult to abs and ΔE G If the difference between Therefore, it becomes difficult to obtain light emission having high energy such as blue light emission.

[0088] From these results, the energy difference between the LUMO level and the HOMO level of the guest material 131 is (ΔE G ) is the transition energy calculated from the absorption edge in the absorption spectrum of the guest material 131. Energy (ΔE abs ) and it is preferable that the value is larger in the range of 0.4 eV or more and 0.8 eV or less. It is more preferable that the guest material 1 is large in the range of 0.5 eV or more and 0.8 eV or less. The luminescence energy (ΔE Em ) is ΔE abs Equal to or smaller than Therefore, the energy difference (ΔE G )teeth, The luminescence energy (ΔE Em ) from 0.4eV to 0.8e It is preferable that the value is large in the range of 0.5 eV or less, and it is preferable that the value is large in the range of 0.5 eV or more and 0.8 eV or less. More preferable.

[0089] In addition, the LUMO level of the guest material 131 is higher than the LUMO level of the host material 132. Since the HOMO level of the guest material 131 is lower than the HOMO level of the host material 132, Carriers (holes and electrons) injected from a pair of electrodes (electrodes 101 and 102) Among these, both the holes injected from the anode and the electrons injected from the cathode are injected into the light-emitting layer 130 In this case, both electrons and holes are easily injected into the host material 132. In order to be injected into the host material 132, the LUMO level of the guest material 131 must be The difference between the LUMO level of the material 132 and the LUMO level of the material 132 is preferably 0.05 eV or more, and more preferably The guest material 13 has a specific surface area of ​​0.1 eV or more, and more preferably 0.2 eV or more. The difference between the HOMO level of 1 and the HOMO level of the host material 132 is preferably 0.05 e V or more, more preferably 0.1 eV or more, and even more preferably 0.2 eV or more is.

[0090] In addition, the energy difference between the LUMO level and the HOMO level of the host material 132 (ΔE H )teeth , the energy difference between the LUMO level and the HOMO level of the guest material 131 (ΔE G ) smaller than Therefore, the carriers (holes and electrons) injected into the light-emitting layer 130 recombine to form excitation currents. As for the excited state, the excited state formed by the host material 132 is more energetically stable. Therefore, most of the excited states generated in the light-emitting layer 130 are formed in the host material 132. Therefore, according to the configuration of one embodiment of the present invention, The excitation energy is easily transferred from the excited state of the host material 132 to the guest material 131. By reducing the voltage, the driving voltage of the light emitting element can be reduced, and the light emitting efficiency can be increased. do.

[0091] In addition, based on the relationship between the LUMO level and the HOMO level described above, the guest material 131 and the host In combination with the material 132, the oxidation potential of the guest material 131 is The reduction potential of the guest material 131 is higher than the reduction potential of the host material 132. By setting the oxidation potential and reduction potential in this way, Similarly, the reaction of forming an exciplex between the guest material 131 and the host material 132 is suppressed. The oxidation potential and reduction potential can be controlled by cyclic voltammetry. It can be measured by the CV method.

[0092] By configuring the light-emitting layer 130 as described above, light emission from the guest material 131 of the light-emitting layer 130 can be prevented. can be obtained efficiently.

[0093] <Energy transfer mechanism> Next, the control of the energy transfer process between the host material 132 and the guest material 131 molecules The mechanism of energy transfer between molecules is the Förster mechanism (bipolar Two mechanisms have been proposed: the electron-dipole interaction (electron-dipole interaction) and the Dexter mechanism (electron exchange interaction). It is being done.

[0094] <Förster mechanism> In the Förster mechanism, energy transfer does not require direct contact between molecules, but occurs via the host Energy transfer occurs through the resonance phenomenon of dipole vibration between the material 132 and the guest material 131. The host material 132 transfers energy to the guest material 131 due to the resonance phenomenon of the dipole vibration. The excited host material 132 returns to the ground state, and the guest material 13 1 becomes excited. The rate constant of the Förster mechanism is k h*→g is shown in formula (1) .

[0095]

number

[0096] In formula (1), ν represents the frequency, and f' h (ν) is the standard value of the host material 132 The emission spectrum (or the fluorescence spectrum when discussing energy transfer from the singlet excited state) spectrum, and phosphorescence spectrum when discussing energy transfer from triplet excited states), ε g (ν) represents the molar absorption coefficient of the guest material 131, N represents Avogadro's number, and n represents the refractive index of the medium, and R represents the intermolecular distance between the host material 132 and the guest material 131. where τ represents the measured lifetime of the excited state (fluorescence lifetime or phosphorescence lifetime), and c represents the speed of light. , φ is the luminescence quantum yield (fluorescence quantum yield when discussing energy transfer from the singlet excited state) represents the phosphorescence quantum yield when discussing energy transfer from the triplet excited state, and K 2 teeth , a coefficient (between 0 and 1) that represents the orientation of the transition dipole moments of the host material 132 and the guest material 131. In the case of random orientation, K 2 =2 / 3.

[0097] Dexter Mechanism In the Dexter mechanism, the host material 132 and the guest material 131 are bonded together, causing orbital overlap. The electrons in the excited host material 132 and the ground state guest material 13 are close to each other. Energy transfer occurs through the exchange of electrons with 1. The rate constant for the Dexter mechanism is k h*→g is shown in equation (2).

[0098]

number

[0099] In equation (2), h is Planck's constant, and K is a constant with the dimension of energy. where ν represents the frequency and f' h (ν) is the normalized emission spectrum of the host material 132. Spectra (fluorescence spectrum when discussing energy transfer from singlet excited states, triplet When discussing energy transfer from an excited state, it represents the phosphorescence spectrum, and ε' g (ν) is , represents the normalized absorption spectrum of the guest material 131, L represents the effective molecular radius, R represents the intermolecular distance between the host material 132 and the guest material 131 .

[0100] Here, the energy transfer efficiency φ from the host material 132 to the guest material 131 ET is a number It is expressed by equation (3). r The emission process of the host material 132 (energy from the singlet excited state) When discussing energy transfer, we use fluorescence; when discussing energy transfer from triplet excited states, we use phosphorus. represents the rate constant of photon transport, k n is the non-radiative process (thermal deactivation and intersystem crossing) of the host material 132. represents the rate constant, and τ represents the measured lifetime of the excited state of the host material 132.

[0101]

number

[0102] From equation (3), the energy transfer efficiency φ ET To increase the energy transfer rate, Degree constant k h*→g By increasing the rate constant k r +k n (=1 / τ) is relatively You know the smaller the better.

[0103] <Concept for enhancing energy transfer> In the energy transfer by the Förster mechanism, the energy transfer efficiency φ ET is the amount quantum yield φ (fluorescence quantum yield when discussing energy transfer from singlet excited states, triplet When discussing energy transfer from the excited state, a higher phosphorescence quantum yield is better. Emission spectrum of host material 132 (when discussing energy transfer from the singlet excited state) is the fluorescence spectrum) and the absorption spectrum of the guest material 131 (from the singlet ground state to the triplet excitation). It is preferable that the overlap with the absorption corresponding to the transition to the excited state is large. It is also preferable that the molar absorption coefficient of the material 131 is high. The absorption spectrum of the guest material 131 overlaps with the absorption band appearing on the longest wavelength side of the absorption spectrum of the guest material 131. This means that...

[0104] In addition, in the energy transfer by the Dexter mechanism, the rate constant k h*→g Enlarge In this study, the emission spectrum of the host material 132 (energy transfer from the singlet excited state) was discussed. When discussing energy transfer from triplet excited states, we use the fluorescence spectrum. Absorption spectra of the 131 (singlet ground state to triplet excited state) and guest material Therefore, the efficiency of energy transfer is The optimization was carried out by comparing the emission spectrum of the host material 132 with the absorption spectrum of the guest material 131. This is achieved by overlapping with the absorption band appearing on the longest wavelength side.

[0105] <Configuration example 2 of light-emitting element> Next, regarding a light-emitting element having a different structure from that shown in FIGS. 1(A) and 1(B), )(B) will be used to explain the following.

[0106] FIG. 3A is a schematic cross-sectional view of a light-emitting element 152 of one embodiment of the present invention. ), the parts having the same functions as those shown in FIG. 1(A) are marked with the same hatch patterns. In addition, parts with similar functions are assigned the same symbols. However, detailed explanations thereof may be omitted.

[0107] The light emitting element 152 has a pair of electrodes (electrode 101 and electrode 102), and The EL layer 100 includes at least a light-emitting layer 135. .

[0108] FIG. 3(B) is a cross-sectional view showing an example of the light-emitting layer 135 shown in FIG. 3(A). The light-emitting layer 135 shown in B) is made of at least a guest material 131, a host material 132, and a host and a vitreous material 133.

[0109] In the light-emitting layer 135, the host material 132 or the host material 133 is the most The guest material 131 is dispersed in the host material 132 and the host material 133. Here, the guest material 131 can convert triplet excitation energy into luminescence. The first material has the function of forming a photoresist, and the host material 132 is the second material. Preferably, 33 is the third material.

[0110] <Light-emitting mechanism of light-emitting elements 2> Next, the light emitting mechanism of the light emitting layer 135 will be described below.

[0111] In the light-emitting element 152 of one embodiment of the present invention, a pair of electrodes (electrode 101 and electrode 102) ) are recombined to form a light-emitting layer of the EL layer 100. The guest material 131 in the semiconductor layer 135 is excited, and the excited guest material 131 emits light. can be obtained.

[0112] Light emission from the guest material 131 is obtained through the following two processes. ·(α) Direct recombination process (β) Energy transfer process

[0113] The (α) direct recombination process is the same as that described in the light-emitting mechanism of the light-emitting layer 130. Since this is similar to the recombination process, the explanation will be omitted here.

[0114] <(β) Energy transfer process> The energy transfer process between the host material 132, the host material 133, and the guest material 131 is shown in FIG. For the purpose of explanation, a schematic diagram for explaining the correlation of energy levels is shown in FIG. 4(A). The notations and symbols in 4(A) are as follows. For other notations and symbols, see Figure 1. Same as 2(A). Host (133): Host material 133 ·S H : S1 level of the host material 133 T H : T1 level of the host material 133

[0115] The carriers recombine in the host material 132, and the host material 132 reaches a singlet excited state. When a triplet excited state is formed, the following two states are shown in Route E1 and Route E2 of FIG. Thus, both the singlet excitation energy and the triplet excitation energy of the host material 132 are T1 level (T PG ), and the guest material 131 transitions to a triplet excited state. The guest material 131 in the triplet excited state emits phosphorescence.

[0116] In addition, the excitation energy is efficiently transferred from the host material 132 to the guest material 131. To do this, the T1 level (T H ) is the T level (T P H ) is preferably higher than the triplet excitation energy of the host material 132. This makes it difficult for quenching to occur, and energy transfer to the guest material 131 occurs efficiently.

[0117] As shown in the energy band diagram in Figure 4(B), the LUMO level of the guest material 131 The LUMO level is higher than the LUMO level of the host material 132 and lower than the HOMO level of the guest material 131. The HOMO level of the guest material 132 is preferably lower than the HOMO level of the host material 132. The energy difference between the LUMO level and the HOMO level of 131 (ΔE G ) is the host material 132 The energy difference between the LUMO level and the HOMO level (ΔE H ) is larger than this. By adjusting the energy level relationship, the guest material 131 and the host material 132 form an exciplex. From this point of view, the light-emitting mechanism of the light-emitting element can be suppressed. As mentioned in 1, the LUMO level of the guest material 131 and the LUMO level of the host material 132 The HOMO level of the guest material 131 and the HOMO level of the host material 132 are the same. etc., which is one aspect of the present invention.

[0118] The LUMO level of the host material 133 is higher than the LUMO level of the host material 132. and the HOMO level of the host material 133 is lower than the HOMO level of the host material 132. That is, the energy between the LUMO level and the HOMO level of the host material 133 is preferably The energy difference is the energy difference (ΔE H ) By establishing such an energy level relationship, the host material 132 and the host The reaction of forming an exciplex with the material 133 can be suppressed. In the figure, Host (133) represents the host material 133, and other notations and symbols are the same as those in FIG. ) is the same as

[0119] The difference between the HOMO level of the host material 132 and the HOMO level of the host material 133, The difference between the LUMO levels of the host material 132 and the host material 133 is The energy is preferably 0.1 eV or more, and more preferably 0.2 eV or more. By having a difference in the capacitance, the electrons injected from the pair of electrodes (electrode 101 and electrode 102) This is preferable because it facilitates the injection of both electron and hole carriers into the host material 132. be.

[0120] The LUMO level of the host material 133 is higher than the LUMO level of the guest material 131. The HOMO level of the host material 133 may be higher or lower than the HOMO level of the guest material 131. It can be higher or lower than the level.

[0121] In addition, the energy difference between the LUMO level and the HOMO level of the host material 132 (ΔE H )teeth , the energy difference between the LUMO level and the HOMO level of the host material 133 is smaller than the energy difference between the LUMO level and the HOMO level of the host material 133. The energy difference between the LUMO level and the HOMO level of material 132 (ΔE H ) is the guest material 1 The energy difference between the LUMO level and the HOMO level of 31 (ΔE G ) and therefore the light-emitting layer The excited state formed by the recombination of the injected carriers (holes and electrons) in 135 is The host material 133 or the guest material 131 forms an excited state, and the host material 132 The excited state formed by the luminescent layer 135 is more stable in terms of energy. Most of the excited states formed by the host material 132 exist as excited states. Therefore, in the light-emitting layer 135, similar to the configuration of the light-emitting layer 130, The excitation energy is easily transferred from the excited state of the host material 132 to the guest material 131. This reduces the driving voltage of the light emitting element 152, thereby increasing the light emitting efficiency. Cut.

[0122] In addition, holes and electrons recombine in the host material 133, and the host material 133 is excited. Even when an excited state is formed, the LUMO level and the HOMO level of the host material 133 are The energy difference is determined by the energy difference between the LUMO level and the HOMO level of the host material 132. Since the excitation energy of the host material 133 is large, the excitation energy of the host material 132 is rapidly transferred to the host material 132. The excitation energy can then be transferred to the light-emitting layer 130 via the light-emitting mechanism described above. Through a similar process, energy is transferred to the guest material 131, and the guest material 131 It should be noted that the host material 133 also regenerates holes and electrons. Considering that the host material 133 can bond to the singlet excited state, similar to the host material 132, Materials with small energy difference between the energy level and triplet excited energy level, especially thermal activation It is preferably a delayed fluorescent material.

[0123] In order to obtain efficient light emission from the guest material 131, the S1 equivalent of the host material 133 must be Rank (S H ) is the S1 level (S PH ) or more, and the host material 133 T1 level (T H ) is the T level (T PH ) or more is preferable.

[0124] In addition, from the relationship between the LUMO level and the HOMO level described above, the host material 133 and the host In combination with the material 132, the oxidation potential of the host material 133 is The reduction potential of the host material 133 is higher than the oxidation potential of the host material 132. By setting the oxidation potential and reduction potential in this way, Similarly to the above, the reaction of forming an exciplex between the host material 133 and the host material 132 is suppressed. It can be controlled.

[0125] In addition, the combination of the host material 132 and the host material 133 has a function of transporting holes. When a material having a function of transporting electrons is combined with a material having a function of transporting electrons, the mixing ratio Therefore, it is possible to easily control the carrier balance. The ratio of the material having the function of transporting electrons to the material having the function of transporting electrons is 1:9 to 9:1 (by weight). In addition, by having this configuration, the carrier balance can be easily controlled. Therefore, the carrier recombination region can be easily controlled.

[0126] By configuring the light-emitting layer 135 as described above, light emission from the guest material 131 of the light-emitting layer 135 can be obtained efficiently.

[0127] <Material> Next, components of a light-emitting element according to one embodiment of the present invention will be described in detail below.

[0128] <Light-emitting layer> In the light-emitting layer 130 and the light-emitting layer 135, the host material 132 contains at least one guest material 132. The guest material 131 (phosphorescent material) is present in a larger amount by weight than the host material 132. It is distributed.

[0129] <Host Material 132> The energy difference between the S1 level and the T1 level of the host material 132 is preferably small. Specifically, it is greater than 0 eV and less than or equal to 0.2 eV.

[0130] The host material 132 has a skeleton having a hole transporting property and a skeleton having an electron transporting property. Alternatively, the host material 132 may preferably have a π-electron rich heteroaromatic ring skeleton or The host preferably has an aromatic amine skeleton and a π-electron-deficient heteroaromatic ring skeleton. The material 132 has the above-described skeleton, which allows a donor-acceptor type excited state to be formed in the molecule. Furthermore, the host material 132 has both donor and acceptor properties in its molecule. In order to make the structure more resistant to electron transport, a skeleton having electron transport properties and a skeleton having hole transport properties are directly bonded. Alternatively, it is preferable that the aromatic ring has a π-electron-rich heteroaromatic skeleton or an aromatic alkyl group. It is preferable that the amine skeleton and the π-electron-deficient aromatic ring skeleton are directly bonded to each other. By strengthening both the donor and acceptor properties within the HOMO domain of the host material 132, The overlap between the region where the molecular orbitals in the LUMO are distributed and the region where the molecular orbitals in the LUMO are distributed The singlet and triplet excited energy levels of the host material 132 can be reduced. It is possible to reduce the energy difference between the host material 132 and the energy level. This makes it possible to maintain the triplet excited energy level at a high energy level.

[0131] Materials with a small energy difference between the singlet and triplet excited energy levels Examples of the thermally activated delayed fluorescent material include a triplet Because the difference between the excited energy level and the singlet excited energy level is small, reverse intersystem crossing occurs. It is a material that has the function of converting energy from a triplet excited state to a singlet excited state. Therefore, the triplet excited state can be upconverted to the singlet excited state by a small amount of thermal energy. It is possible to undergo reverse intersystem crossing and efficiently emit light (fluorescence) from the singlet excited state. In addition, the condition for efficiently obtaining thermally activated delayed fluorescence is that triplet excitation energy The energy difference between the singlet excited energy level and the singlet excited energy level is preferably greater than 0 eV. It is preferably 0.2 eV or less, and more preferably more than 0 eV and 0.1 eV or less. can be.

[0132] When the thermally activated delayed fluorescent material is composed of one kind of material, for example, the following material is used: It is possible.

[0133] First, fullerene and its derivatives, acridine derivatives such as proflavine, and eosin are listed. In addition, magnesium (Mg), zinc (Zn), cadmium (Cd), tin (S n), platinum (Pt), indium (In), or palladium (Pd) Examples of the metal-containing porphyrin include protoporphyrin. Porphyrin-tin fluoride complex (SnF2(Proto IX)), mesoporphyrin-fluoride Tin complex (SnF2(Meso IX)), hematoporphyrin-tin fluoride complex (Sn F2 (Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride Complex (SnF2(Copro III-4Me)), Octaethylporphyrin-Fluoride Tin complex (SnF2(OEP)), etioporphyrin-tin fluoride complex (SnF2(E tio I)), octaethylporphyrin-platinum chloride complex (PtCl2OEP), etc. It can be obtained.

[0134] [ka]

[0135] In addition, as a thermally activated delayed fluorescent material composed of one kind of material, π-electron-rich heteroaromatic Heterocyclic compounds having an aromatic ring and a π-electron-deficient heteroaromatic ring can also be used. is 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3- a]carbazol-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol {4,6-diphenyl-1,3,5-triazine (PC CzPTzn), 2-[4-(10H-phenoxazin-10-yl)phenyl]-4, 6-Diphenyl-1,3,5-triazine (abbreviation: PXZ-TRZ), 3-[4-(5- Phenyl-5,10-dihydrophenazin-10-yl)phenyl]-4,5-diphenyl PPZ-3TPT, 3-(9,9-dimethyl- 9H-Acridine-10-yl)-9H-xanthen-9-one (Abbreviation: ACRXTN) , bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviation: DMAC-DPS), 10-phenyl-10H,10'H-spiro[acridine -9,9'-anthracene]-10'-one (abbreviation: ACRSA), etc. The heterocyclic compounds have a π-electron rich heteroaromatic ring and a π-electron deficient heteroaromatic ring, Among them, a skeleton having a π-electron-deficient heteroaromatic ring is preferred. Among them, diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton) or triazine skeleton The azine skeleton is preferred because it is stable and reliable. Among the skeletons having such structures, acridine skeleton, phenoxazine skeleton, phenothiazine skeleton, furanoside skeleton, The thiophene, pyrrole, and thiophene skeletons are stable and reliable, so It is preferable that the compound has one or more selected from the following. The dibenzofuran skeleton is used as the thiophene skeleton, and the dibenzothiophene skeleton is used as the thiophene skeleton. The pyrrole skeleton includes an indole skeleton, a carbazole skeleton, and 3-(9-phenyl-9H-carbazol-3-yl)-9H-carbazole skeleton, In addition, a heteroaromatic ring in which a π-electron rich ring and a π-electron deficient ring are directly bonded is preferred. The material has donor properties of π-electron rich heteroaromatic rings and acceptor properties of π-electron deficient heteroaromatic rings. are both strong, and the difference between the levels of the singlet excited state and the triplet excited state becomes small, so preferable.

[0136] [ka]

[0137] In addition, examples of the skeleton having a π-electron-deficient heteroaromatic ring include condensed heteroaromatic rings having a diazine skeleton. The ring skeleton is preferred because it is more stable and reliable, and among these, the benzofuropyrimidine skeleton and The benzothienopyrimidine skeleton is particularly preferred because of its high acceptor property. An example of the pyrimidine skeleton is a benzofuro[3,2-d]pyrimidine skeleton. In addition, the benzothienopyrimidine skeleton may be, for example, benzothieno[3,2-d] A pyrimidine skeleton is an example.

[0138] As a skeleton having a π-electron-rich heteroaromatic ring, a bicarbazole skeleton is The bicarbazole skeleton is preferably a bicarbazole skeleton having a high viscosity, stability, and good reliability. A bicarbazole skeleton in which two carbazolyl groups are bonded to each other at any of the positions 1 to 4. The bicarbazole skeleton is particularly preferred because of its high donor property. ,2'-bi-9H-carbazole skeleton, 3,3'-bi-9H-carbazole skeleton, 4,4 '-bi-9H-carbazole skeleton, 2,3'-bi-9H-carbazole skeleton, 2,4'- Bi-9H-carbazole skeleton, 3,4'-bi-9H-carbazole skeleton, etc. .

[0139] From the viewpoint of widening the band gap and increasing the triplet excitation energy, The 9-position of one of the carbazolyl groups in the bicarbazole skeleton is directly linked to benzofuropyrimidinone. Compounds bonded to a benzothienopyrimidine skeleton or a benzothienopyrimidine skeleton are preferred. A carbazole skeleton and a benzofuropyrimidine skeleton or a benzothienopyrimidine skeleton When directly bonded, it becomes a compound with a relatively low molecular weight, which is suitable for vacuum deposition (relatively low temperature). Generally, when the molecular weight is low, the heat resistance after film formation is low. Although the activity is often low, benzofuropyrimidine skeleton, benzothienopyrimidine skeleton, Since the bicarbazole skeleton is a rigid skeleton, compounds having this skeleton have a relatively high molecular weight. Even if the temperature is relatively low, sufficient heat resistance can be obtained. This is preferable because it increases the band gap and raises the excitation energy level.

[0140] In addition, a bicarbazole skeleton and a benzofuropyrimidine skeleton or a benzothienopyrimidine skeleton are also included. and the alkylene skeleton is bonded via an arylene group, and the number of carbon atoms in the arylene group is When the number of carbon atoms is 6 to 25, preferably 6 to 13, the band gap and triplet Not only can both excitation energies be kept high, but the resulting compounds have relatively low molecular weights. This results in a structure that is suitable for vacuum deposition (vacuum deposition can be performed at a relatively low temperature).

[0141] In addition, the bicarbazole skeleton is bonded directly or via an arylene group to benzofuro[3,2 -d]pyrimidine backbone or benzothieno[3,2-d]pyrimidine backbone. More preferably, the benzofuro[3,2-d]pyrimidine skeleton or the benzothieno[3,2- d) By bonding to the 4-position of the pyrimidine skeleton, the compound has excellent carrier transport properties. Therefore, a light-emitting element using the compound can be driven at a low voltage. do.

[0142] <Examples of compounds> The compound of one embodiment of the present invention shown above is a compound represented by the following general formula (G0): .

[0143] [ka]

[0144] In the above general formula (G0), A represents a substituted or unsubstituted benzofuropyrimidine skeleton. or a benzothienopyrimidine skeleton. When the zothienopyrimidine skeleton has a substituent, the substituent may be a C1 to C6 an alkyl group, a cycloalkyl group having 3 to 7 carbon atoms, or a substituted or unsubstituted alkyl group having 6 to 13 carbon atoms; An unsubstituted aryl group can also be selected as a substituent. Specific examples of the group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, Examples include an isobutyl group, a tert-butyl group, and an n-hexyl group. Specific examples of the cycloalkyl group having 3 to 7 carbon atoms include a cyclopropyl group, a cyclobutene group, and a cyclobutene group. Examples of the alkyl group include cyclohexyl, cyclopentyl, and cyclohexyl. The aryl group having 6 to 13 carbon atoms includes a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, and the like. Specific examples include a methyl group and a methyl group.

[0145] Also, R 1 ~R 15 are each independently hydrogen or a substituted or unsubstituted group having 1 to 10 carbon atoms; a substituted or unsubstituted alkyl group having 3 to 7 carbon atoms, or a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms; or an unsubstituted aryl group having 6 to 13 carbon atoms. Specific examples of alkyl groups include methyl, ethyl, propyl, isopropyl, and butyl groups. Examples of the alkyl group include an isobutyl group, a tert-butyl group, and an n-hexyl group. Specific examples of the cycloalkyl group having 3 to 7 carbon atoms include a cyclopropyl group, ... Examples of the alkyl group include a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group. Examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, a naphthyl group, a biphenyl group, a fluoro group, and the like. Specific examples include the alkyl group and cyclohexane group. The alkyl group and the aryl group may have a substituent, and the substituents are bonded to each other. The substituent may be an alkyl group having 1 to 6 carbon atoms, a group having 3 or more carbon atoms, or a group having 4 or more carbon atoms. A cycloalkyl group having from 1 to 7 carbon atoms or an aryl group having from 6 to 13 carbon atoms may also be selected as a substituent. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, Propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, n-hexyl group Examples of the cycloalkyl group having 3 to 7 carbon atoms include a cycloalkyl group and a cycloalkyl group. Specifically, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, etc. Examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, Specific examples include a naphthyl group, a biphenyl group, and a fluorenyl group.

[0146] Also, Ar 1 represents an arylene group having 6 to 25 carbon atoms or a single bond, The alkyl group may have a substituent, and the substituents may be bonded to each other to form a ring. An example of such a compound is a compound in which the carbon atom at the 9th position of the fluorenyl group has a phenyl group as a substituent. The two phenyl groups bond together to form a spirofluorene skeleton. Examples of the arylene group having 6 to 25 carbon atoms include a phenylene group, Specific examples include naphthylene group, biphenyldiyl group, and fluorenediyl group. In addition, when the arylene group has a substituent, the substituent may be a group having a carbon number of an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms, or a An aryl group can also be selected as a substituent. Examples of alkyl groups having 1 to 6 carbon atoms include Specifically, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group groups, tert-butyl groups, n-hexyl groups, etc. Specific examples of the cycloalkyl group of the seventh to seventh series include a cyclopropyl group, a cyclobutyl group, a cyclobutyl group, a cyclopropyl ... and cyclopentyl and cyclohexyl groups. The aryl group includes a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, etc. can be cited as an example.

[0147] In the compound of the present embodiment, the benzofuropyrimidine skeleton is A 2[3,2-d]pyrimidine skeleton is preferred.

[0148] In the compound of the present embodiment, the benzothienopyrimidine skeleton is A thieno[3,2-d]pyrimidine skeleton is preferred.

[0149] In the compound of the present embodiment, one carbazole group of the bicarbazole skeleton is benzofuro[3,2-d]pyridine is attached to the 9-position of the aryl group either directly or via an arylene group. The structure bonded to the 4-position of the pyrimidine skeleton or benzothieno[3,2-d]pyrimidine skeleton Compounds with this property have both strong donor and acceptor properties and a wide band gap. Therefore, it can be suitably used in light-emitting elements that emit high-energy light, such as blue light. This is a preferable configuration. The compound is a compound represented by the following general formula (G1).

[0150] [ka]

[0151] In the above general formula (G1), Q represents oxygen or sulfur.

[0152] Also, R 1 ~R 20are each independently hydrogen or a substituted or unsubstituted group having 1 to 10 carbon atoms; a substituted or unsubstituted alkyl group having 3 to 7 carbon atoms, or a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms; or an unsubstituted aryl group having 6 to 13 carbon atoms. Specific examples of alkyl groups include methyl, ethyl, propyl, isopropyl, and butyl groups. Examples of the alkyl group include an isobutyl group, a tert-butyl group, and an n-hexyl group. Specific examples of the cycloalkyl group having 3 to 7 carbon atoms include a cyclopropyl group, ... Examples of the alkyl group include a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group. Examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, a naphthyl group, a biphenyl group, a fluoro group, and the like. Specific examples include the alkyl group and cyclohexane group. The alkyl group and the aryl group may have a substituent, and the substituents are bonded to each other. The substituent may be an alkyl group having 1 to 6 carbon atoms, a group having 3 or more carbon atoms, or a group having 4 or more carbon atoms. A cycloalkyl group having from 1 to 7 carbon atoms or an aryl group having from 6 to 13 carbon atoms may also be selected as a substituent. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, Propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, n-hexyl group Examples of the cycloalkyl group having 3 to 7 carbon atoms include a cycloalkyl group and a cycloalkyl group. Specifically, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, etc. Examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, Specific examples include a naphthyl group, a biphenyl group, and a fluorenyl group.

[0153] Also, Ar 1represents an arylene group having 6 to 25 carbon atoms or a single bond, The alkyl group may have a substituent, and the substituents may be bonded to each other to form a ring. An example of such a compound is a compound in which the carbon atom at the 9th position of the fluorenyl group has a phenyl group as a substituent. The two phenyl groups bond together to form a spirofluorene skeleton. Examples of the arylene group having 6 to 25 carbon atoms include a phenylene group, Specific examples include naphthylene group, biphenyldiyl group, and fluorenediyl group. In addition, when the arylene group has a substituent, the substituent may be a group having a carbon number of an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms, or a An aryl group can also be selected as a substituent. Examples of alkyl groups having 1 to 6 carbon atoms include Specifically, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group groups, tert-butyl groups, n-hexyl groups, etc. Specific examples of the cycloalkyl group of the seventh to seventh series include a cyclopropyl group, a cyclobutyl group, a cyclobutyl group, a cyclopropyl ... and cyclopentyl and cyclohexyl groups. The aryl group includes a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, etc. can be cited as an example.

[0154] In the compound of the present embodiment, the bicarbazole skeleton is 3,3'-bi- It has a 9H-carbazole skeleton, and one of the carbazolyl groups of the bicarbazole skeleton is at the 9-position. In the compound, the benzofuro[3,2-d]pyrimidine skeleton or or a compound having a structure bonded to the 4-position of the benzothieno[3,2-d]pyrimidine skeleton. Since the light-emitting element using this compound has excellent carrier transport properties, it can be driven at a low voltage, and therefore is preferred. This is a preferable configuration. The compound is a compound represented by the following general formula (G2).

[0155] [ka]

[0156] In the above general formula (G2), Q represents oxygen or sulfur.

[0157] Also, R 1 ~R 20 are each independently hydrogen or a substituted or unsubstituted group having 1 to 10 carbon atoms; a substituted or unsubstituted alkyl group having 3 to 7 carbon atoms, or a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms; or an unsubstituted aryl group having 6 to 13 carbon atoms. Specific examples of alkyl groups include methyl, ethyl, propyl, isopropyl, and butyl groups. Examples of the alkyl group include an isobutyl group, a tert-butyl group, and an n-hexyl group. Specific examples of the cycloalkyl group having 3 to 7 carbon atoms include a cyclopropyl group, ... Examples of the alkyl group include a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group. Examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, a naphthyl group, a biphenyl group, a fluoro group, and the like. Specific examples include the alkyl group and cyclohexane group. The alkyl group and the aryl group may have a substituent, and the substituents are bonded to each other. The substituent may be an alkyl group having 1 to 6 carbon atoms, a group having 3 or more carbon atoms, or a group having 4 or more carbon atoms. A cycloalkyl group having from 1 to 7 carbon atoms or an aryl group having from 6 to 13 carbon atoms may also be selected as a substituent. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, Propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, n-hexyl group Examples of the cycloalkyl group having 3 to 7 carbon atoms include a cycloalkyl group and a cycloalkyl group. Specifically, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, etc. Examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, Specific examples include a naphthyl group, a biphenyl group, and a fluorenyl group.

[0158] Also, Ar 1 represents an arylene group having 6 to 25 carbon atoms or a single bond, The alkyl group may have a substituent, and the substituents may be bonded to each other to form a ring. An example of such a compound is a compound in which the carbon atom at the 9th position of the fluorenyl group has a phenyl group as a substituent. The two phenyl groups bond together to form a spirofluorene skeleton. Examples of the arylene group having 6 to 13 carbon atoms include a phenylene group, Specific examples include naphthylene group, biphenyldiyl group, and fluorenediyl group. In addition, when the arylene group has a substituent, the substituent may be a group having a carbon number of an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms, or a An aryl group can also be selected as a substituent. Examples of alkyl groups having 1 to 6 carbon atoms include Specifically, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group groups, tert-butyl groups, n-hexyl groups, etc. Specific examples of the cycloalkyl group of the seventh to seventh series include a cyclopropyl group, a cyclobutyl group, a cyclobutyl group, a cyclopropyl ... and cyclopentyl and cyclohexyl groups. The aryl group includes a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, etc. can be cited as an example.

[0159] In addition, in the compound of this embodiment, a bicarbazole skeleton and a benzofuropyrin skeleton are When the benzothienopyrimidine skeleton or the benzothienopyrimidine skeleton is directly bonded to the benzothienopyrimidine skeleton, This is a desirable configuration because it has a wide band gap and can be synthesized with high purity. In addition, since the compound has excellent carrier transport properties, a light-emitting element using the compound has low It can be driven at a low voltage.

[0160] In addition, in the above general formula (G1) or (G2), R 1 ~R 14 , and R 16 ~ R 20 However, if all of the hydrogen is hydrogen, it is advantageous in terms of ease of synthesis and cost of raw materials. In addition, since the compound has a relatively low molecular weight, it has a structure suitable for vacuum deposition, which is particularly preferable. The compound is a compound represented by the following general formula (G3) or general formula (G4).

[0161] [ka]

[0162] In the above general formula (G3), Q represents oxygen or sulfur.

[0163] Also, R 15 is hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, or unsubstituted cycloalkyl groups having 3 to 7 carbon atoms, or substituted or unsubstituted cycloalkyl groups having 6 carbon atoms. The alkyl group having 1 to 6 carbon atoms is specifically an aryl group having 1 to 6 carbon atoms. is a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a te Examples of the alkyl group include a t-butyl group and an n-hexyl group. Specific examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, and a cyclopentyl group. Examples of the alkyl group include aryl groups having 6 to 13 carbon atoms and cyclohexyl groups. Specific examples of the alkyl group include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. Furthermore, the above-mentioned alkyl, cycloalkyl and aryl groups can be mentioned. The alkyl group may have a substituent, and the substituents may be bonded to each other to form a ring. Examples of the substituent include an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms, Alternatively, an aryl group having 6 to 13 carbon atoms can also be selected as a substituent. Specific examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and an isopropyl group. Examples include butyl, isobutyl, tert-butyl, and n-hexyl groups. Specific examples of the cycloalkyl group having 3 to 7 carbon atoms include cyclopropyl. Examples of the cycloalkyl group include a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group. The aryl group having 6 to 13 carbon atoms includes a phenyl group, a naphthyl group, and a biphenyl group. , fluorenyl group, and the like can be mentioned as specific examples.

[0164] Also, Ar 1 represents an arylene group having 6 to 25 carbon atoms or a single bond, The alkyl group may have a substituent, and the substituents may be bonded to each other to form a ring. An example of such a compound is a compound in which the carbon atom at the 9th position of the fluorenyl group has a phenyl group as a substituent. The two phenyl groups bond together to form a spirofluorene skeleton. Examples of the arylene group having 6 to 25 carbon atoms include a phenylene group, Specific examples include naphthylene group, biphenyldiyl group, and fluorenediyl group. In addition, when the arylene group has a substituent, the substituent may be a group having a carbon number of an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms, or a An aryl group can also be selected as a substituent. Examples of alkyl groups having 1 to 6 carbon atoms include Specifically, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group groups, tert-butyl groups, n-hexyl groups, etc. Specific examples of the cycloalkyl group of the seventh to seventh series include a cyclopropyl group, a cyclobutyl group, a cyclobutyl group, a cyclopropyl ... and cyclopentyl and cyclohexyl groups. The aryl group includes a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, etc. can be cited as an example.

[0165] [ka]

[0166] In the above general formula (G4), Q represents oxygen or sulfur.

[0167] Also, R 15 is hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, or unsubstituted cycloalkyl groups having 3 to 7 carbon atoms, or substituted or unsubstituted cycloalkyl groups having 6 carbon atoms. The alkyl group having 1 to 6 carbon atoms is specifically an aryl group having 1 to 6 carbon atoms. is a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a te Examples of the alkyl group include a t-butyl group and an n-hexyl group. Specific examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, and a cyclopentyl group. Examples of the alkyl group include aryl groups having 6 to 13 carbon atoms and cyclohexyl groups. Specific examples of the alkyl group include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. Furthermore, the above-mentioned alkyl, cycloalkyl and aryl groups can be mentioned. The alkyl group may have a substituent, and the substituents may be bonded to each other to form a ring. Examples of the substituent include an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms, Alternatively, an aryl group having 6 to 13 carbon atoms can also be selected as a substituent. Specific examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and an isopropyl group. Examples include butyl, isobutyl, tert-butyl, and n-hexyl groups. Specific examples of the cycloalkyl group having 3 to 7 carbon atoms include cyclopropyl. Examples of the cycloalkyl group include a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group. The aryl group having 6 to 13 carbon atoms includes a phenyl group, a naphthyl group, and a biphenyl group. , fluorenyl group, and the like can be mentioned as specific examples.

[0168] Also, Ar 1 represents an arylene group having 6 to 25 carbon atoms or a single bond, The alkyl group may have a substituent, and the substituents may be bonded to each other to form a ring. An example of such a compound is a compound in which the carbon atom at the 9th position of the fluorenyl group has a phenyl group as a substituent. The two phenyl groups bond together to form a spirofluorene skeleton. Examples of the arylene group having 6 to 25 carbon atoms include a phenylene group, Specific examples include naphthylene group, biphenyldiyl group, and fluorenediyl group. In addition, when the arylene group has a substituent, the substituent may be a group having a carbon number of an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms, or a An aryl group can also be selected as a substituent. Examples of alkyl groups having 1 to 6 carbon atoms include Specifically, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group groups, tert-butyl groups, n-hexyl groups, etc. Specific examples of the cycloalkyl group of the seventh to seventh series include a cyclopropyl group, a cyclobutyl group, a cyclobutyl group, a cyclopropyl ... and cyclopentyl and cyclohexyl groups. The aryl group includes a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, etc. can be cited as an example.

[0169] In the general formula (G0), the benzofuropyrimidine skeleton or benzothiamine skeleton represented by A is Examples of the enopyrimidine skeleton include those represented by the following structural formulas (Ht-1) to (Ht-24). The structures that can be used for A are as follows: Not limited to.

[0170] [ka]

[0171] [ka]

[0172] In the structural formulas (Ht-1) to (Ht-24), R 16 ~R 20 are respectively independently, hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted a cycloalkyl group having 3 to 7 carbon atoms, or a substituted or unsubstituted cycloalkyl group having 6 to 13 carbon atoms; Specific examples of alkyl groups having 1 to 6 carbon atoms include methyl, group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group Examples of the cycloalkyl group include a cycloalkyl group having 3 to 7 carbon atoms and an n-hexyl group. Specific examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, Examples of the aryl group having 6 to 13 carbon atoms include a cyclohexyl group and the like. Specific examples of the alkyl group include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. Furthermore, the alkyl, cycloalkyl, and aryl groups described above may be substituted. The substituents may be bonded to each other to form a ring. Examples of the alkyl group include an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms, and a carbon Aryl groups having 6 to 13 carbon atoms can also be selected as substituents. Specific examples of alkyl groups include methyl, ethyl, propyl, isopropyl, and butyl. Examples of the alkyl group include an isobutyl group, a tert-butyl group, and an n-hexyl group. Specific examples of the cycloalkyl group having 3 to 7 carbon atoms include a cyclopropyl group, a cyclopropyl group, and a cyclopropyl group. butyl group, cyclopentyl group, cyclohexyl group, etc. The aryl group having 6 to 13 carbon atoms includes a phenyl group, a naphthyl group, a biphenyl group, a fluorene group, and the like. Specific examples include a hydroxyl group and a hydroxyl group.

[0173] In addition, in the general formulae (G0) and (G1), it can be used as a bicarbazole skeleton. Examples of structures that can be obtained include structures represented by the following structural formulas (Cz-1) to (Cz-9). The following structure can be used as the bicarbazole skeleton: Not limited to these.

[0174] [ka]

[0175] [ka]

[0176] In the structural formulae (Cz-1) to (Cz-9), R 1 ~R 15 are independent of each other hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted carbon atom, a cycloalkyl group having 3 to 7 prime atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms; Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, Ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group and n-hexyl groups. Also, cycloalkyl groups having 3 to 7 carbon atoms are suitable. Specific examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl ... Examples of the aryl group having 6 to 13 carbon atoms include: Specific examples include phenyl, naphthyl, biphenyl, and fluorenyl groups. Furthermore, the alkyl group, cycloalkyl group, and aryl group may have a substituent. The substituents may be bonded to each other to form a ring. is an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms, or a cycloalkyl group having 6 carbon atoms. An aryl group having 1 to 13 carbon atoms can also be selected as a substituent. Specific examples of the group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, Examples include an isobutyl group, a tert-butyl group, and an n-hexyl group. Specific examples of the cycloalkyl group having 3 to 7 carbon atoms include a cyclopropyl group, a cyclobutyl group, and a cyclopropyl group. cyclopentyl, cyclohexyl, and the like. The aryl groups of 1 to 13 include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. Specific examples include groups such as:

[0177] In the general formulae (G0) to (G4), Ar 1 The arylene group represented by the following formula: For example, groups represented by the following structural formulas (Ar-1) to (Ar-27) can be used. In addition, Ar 1 The groups that can be used as are not limited to these, and groups having a substituent are also usable as That's fine.

[0178] [ka]

[0179] [ka]

[0180] In addition, R in the above general formulas (G1) and (G2) 1 ~R 20 , R in general formula (G0) 1 ~ R15 , R in general formulas (G3) and (G4) 15 an alkyl group represented by the formula The group or aryl group is, for example, a group represented by the following structural formulas (R-1) to (R-29): It is possible to apply the following. The groups that can be used are not limited to these, and may have a substituent.

[0181] [ka]

[0182] <Specific examples of compounds> Specific structures of the compounds represented by the above general formulae (G0) to (G4) include the following: The compounds represented by the general formula (G The compounds represented by (G0) to (G4) are not limited to the following examples.

[0183] [ka]

[0184] [ka]

[0185] [ka]

[0186] [ka]

[0187] [ka]

[0188] [ka]

[0189] [ka]

[0190] [ka]

[0191] The host material 132 has a singlet excited energy level and a triplet excited energy level. It is preferable that the energy difference between the two is small, but it is not necessarily required that the reverse intersystem crossing efficiency is high. The luminescence quantum yield does not have to be high, and the function of exhibiting thermally activated delayed fluorescence does not have to be present. In this case, the host material 132 may have a backbone having a π-electron rich heteroaromatic ring or an aromatic amine. At least one of the phenylene skeleton and the skeleton having a π-electron deficient heteroaromatic ring is m-phenylene. a structure in which the compound is bonded via a structure having at least one of a group or an o-phenylene group Alternatively, it is preferable that the bond is via a biphenyldiyl group. or an arylene group having at least one m-phenylene group or o-phenylene group; and the arylene group is preferably a biphenyldiyl group. It is more preferable that the host material 132 has the above structure. In this case, the T1 level of π-electron deficient heteroaromatic The skeletons with aromatic rings are diazine skeletons (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton) It is preferable that the compound has a π-electron-rich heteroaromatic ring. The skeletons that can be used are acridine skeleton, phenoxazine skeleton, phenothiazine skeleton, furan skeleton, thiazine skeleton, having one or more selected from the group consisting of an olefin skeleton and a pyrrole skeleton; The preferred furan skeleton is a dibenzofuran skeleton, and the preferred thiophene skeleton is The pyrrole skeleton is preferably an indobenzothiophene skeleton. 3-(9-phenyl-9H-carbazol-3-yl) )-9H-carbazole skeleton is particularly preferred. A so-called tertiary amine having no bond is preferred, and a triarylamine skeleton is particularly preferred. The aryl group of the triarylamine skeleton has 6 to 10 carbon atoms forming a ring. The substituted or unsubstituted aryl group of 13 is preferred, and a phenyl group, a naphthyl group, a fluorenyl group, groups, etc.

[0192] Examples of the above-mentioned skeleton having an aromatic amine skeleton and a π-electron-rich heteroaromatic ring include: The skeletons are represented by the following general formulas (401) to (417). X in (416) represents an oxygen atom or a sulfur atom.

[0193] [ka]

[0194] Furthermore, an example of the skeleton having the π-electron-deficient heteroaromatic ring is a skeleton represented by the following general formula (20 The skeleton is represented by (1) through (218).

[0195] [ka]

[0196] A skeleton with hole transport properties (specifically, a π-electron-rich heteroaromatic skeleton or aromatic amine) At least one of the skeletons) and a skeleton having electron transport properties (specifically, a π-electron deficient heteroaromatic ring skeleton) and a bond having at least one m-phenylene group or o-phenylene group When the bond is formed via a group, when the bond is formed via a biphenyldiyl group as a bonding group, has an arylene group having at least one m-phenylene group or o-phenylene group. When bonding is performed via a bonding group, examples of the bonding group include those represented by the following general formulas (301) to (302). The arylene group is a group represented by the formula (315). , biphenyldiyl skeleton, naphthalenediyl skeleton, fluorenediyl skeleton, phenanthrene Examples include a benzoyl skeleton.

[0197] [ka]

[0198] The aromatic amine skeleton (specifically, triarylamine skeleton), π-electron-rich heterocyclic Aromatic ring skeleton (specifically, acridine skeleton, phenoxazine skeleton, phenothiazine skeleton, orchid skeleton, thiophene skeleton, pyrrole skeleton), π-electron deficient heteroaromatic skeleton ( Specifically, a ring having a diazine skeleton or a triazine skeleton), or the above general formula (4 01) to (417), general formulas (201) to (218), and general formulas (301) to ( 315) may have a substituent. The substituent may be a group having 1 to 6 carbon atoms. an alkyl group, a cycloalkyl group having 3 to 6 carbon atoms, or a cycloalkyl group having 6 to 12 carbon atoms; A substituted or unsubstituted aryl group having 1 to 10 carbon atoms can also be selected as a substituent. Specific examples of alkyl groups having 6 carbon atoms include methyl, ethyl, propyl, and isopropyl. Examples of suitable alkyl groups include butyl, isobutyl, tert-butyl, and n-hexyl groups. Specific examples of the cycloalkyl group having 3 to 6 carbon atoms include cycloalkyl groups such as Examples of the cyclopropyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group. The aryl group having 6 to 12 carbon atoms can be a phenyl group, a naphthyl group, or the like. Specific examples include a phenyl group and a biphenyl group. They may be bonded to form a ring. Examples of such a ring include the fluorene skeleton When the carbon atom at position 9 has two phenyl groups as substituents, the phenyl groups are bonded to each other. In this case, a spirofluorene skeleton is formed. In this case, it is advantageous in terms of ease of synthesis and the cost of raw materials.

[0199] Also, Ar 2 represents an arylene group having 6 to 13 carbon atoms, and the arylene group is The substituents may be bonded to each other to form a ring. For example, the carbon atom at the 9th position of the fluorenyl group has two phenyl groups as substituents, When the phenyl groups are bonded to each other to form a spirofluorene skeleton, Examples of the arylene group having 6 to 13 carbon atoms include a phenylene group, a naphthylene group, and the like. Specific examples include a ethylene group, a biphenylene group, and a fluorenediyl group. In addition, when the arylene group has a substituent, the substituent may be a group having 1 to 2 carbon atoms. an alkyl group having 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or a cycloalkyl group having 6 to 6 carbon atoms; Aryl groups having 1 to 6 carbon atoms can also be selected as substituents. Specific examples of alkyl groups include methyl, ethyl, propyl, isopropyl, and butyl. Examples of the alkyl group include an isobutyl group, a tert-butyl group, and an n-hexyl group. Specific examples of the cycloalkyl group having 3 to 6 carbon atoms include a cyclopropyl group, Examples include a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group. Examples of the aryl group having 6 to 12 carbon atoms include a phenyl group, a naphthyl group, and a biphenyl group. Specific examples include groups such as:

[0200] Also, Ar 2 The arylene group represented by the structural formula (Ar-1) to (Ar -18) can be applied. 2 Can be used as The groups are not limited to these.

[0201] Also, R 21 and R 22 are each independently hydrogen, alkyl having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or a substituted cycloalkyl group having 6 to 13 carbon atoms; or an unsubstituted aryl group. Specifically, the alkyl group includes a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, and the like. Examples of the alkyl group include a 3-carbon alkyl group, a tert-butyl group, and an n-hexyl group. Specific examples of the cycloalkyl group having 6 to 10 carbon atoms include a cyclopropyl group, a cyclobutyl group, and a cyclopropyl group. cyclopentyl, cyclohexyl, and the like. Examples of the aryl group having 1 to 13 carbon atoms include a phenyl group, a naphthyl group, a biphenyl group, a fluoro group, and the like. Specific examples include phenyl groups and the aryl groups mentioned above. The alkyl group may have a substituent, and the substituents may be bonded to each other to form a ring. The substituents include alkyl groups having 1 to 6 carbon atoms, cycloalkyl groups having 3 to 6 carbon atoms, and the like. An alkyl group or an aryl group having 6 to 12 carbon atoms can also be selected as a substituent. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, and a propyl group. propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, n-hexyl group Examples of cycloalkyl groups having 3 to 6 carbon atoms include: Specifically, the cyclopropyl group, the cyclobutyl group, the cyclopentyl group, the cyclohexyl group, Examples of the aryl group having 6 to 12 carbon atoms include fluoro groups. Specific examples include a phenyl group, a naphthyl group, and a biphenyl group.

[0202] Also, R 21 and R 22 The alkyl group or aryl group represented by the following structure is, for example, Groups represented by formulas (R-1) to (R-29) can be used. The groups that can be used as the aryl group are not limited to these.

[0203] In addition, the general formulae (401) to (417), the general formulae (201) to (218), and the general formula ( 301) to (315), and Ar 2 , R 21 and R 22 The substituents that may be carried by For example, alkyl groups or aryl groups represented by the above structural formulas (R-1) to (R-24) The alkyl group or the aryl group can be used. The groups are not limited to these.

[0204] In addition, the emission peak of the host material 132 is triplet of that of the guest material 131 (phosphorescent material). Term MLCT (Metal to Ligand Charge Transfer) transition The host material 132 and the It is preferable to select a guest material 131 (phosphorescent material). However, the thermal activation delay can be used instead of the phosphorescent material. When using fluorescent materials, the absorption band on the longest wavelength side is the singlet absorption band. preferable.

[0205] <Guest Material 131> The guest material 131 (phosphorescent material) is an iridium, rhodium, or platinum-based organic material. Metal complexes, or metal complexes, among which organic iridium complexes, e.g., iridium The orthometalated complex is preferably a 4H-triazole. Ligand, 1H-triazole ligand, imidazole ligand, pyridine ligand, pyrimidine The metal complexes include a pyrazine ligand, an isoquinoline ligand, and the like. Examples include platinum complexes having porphyrin ligands.

[0206] In addition, the guest material 131 (phosphorescent material) is a material having a LUMO level lower than that of the host material 132. It has a high LUMO level and a HOMO level lower than the HOMO level of the host material 132. It is preferable to select the host material 132 and the guest material 131 (phosphorescent material) so that This makes it possible to provide a light-emitting element with high luminous efficiency that can be driven at a low voltage.

[0207] Examples of substances having a green or yellow emission peak include tris(4-methyl-6 -phenylpyrimidinato)iridium(III) (abbreviation: Ir(mppm)3), tris (4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: Ir(t Buppm)3), (acetylacetonato)bis(6-methyl-4-phenylpyrimidina Iridium(III) (abbreviation: Ir(mppm)2(acac)), (acetylacetonate) Tritonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium(III) ) (abbreviation: Ir(tBuppm)2(acac)), (acetylacetonato)bis[4- (2-norbornyl)-6-phenylpyrimidinato]iridium(III) (abbreviation: Ir (nbppm)2(acac)), (acetylacetonato)bis[5-methyl-6-(2 -methylphenyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: Ir( mpmppm)2(acac)), (acetylacetonato)bis{4,6-dimethyl-2 -[6-(2,6-dimethylphenyl)-4-pyrimidinyl-κN3]phenyl-κC} Iridium(III) (abbreviation: Ir(dmppm-dmp)2(acac)), (acetylacetonate Iridium(III) Organometallic iridium with a pyrimidine skeleton, such as Ir(dppm)2(acac) Complexes and (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazinato)i Iridium(III) (abbreviation: Ir(mppr-Me)2(acac)), (acetylacetonate thionato)bis(5-isopropyl-3-methyl-2-phenylpyrazinato)iridium( III) (abbreviation: Ir(mppr-iPr)2(acac)) Organometallic iridium complexes and tris(2-phenylpyridinato-N,C 2’ ) Iriji Ir(ppy)3, bis(2-phenylpyridinato-N,C 2 ’ ) Iridium(III) acetylacetonate (abbreviation: Ir(ppy)2(acac) ), bis(benzo[h]quinolinato)iridium(III) acetylacetonate (abbreviation :Ir(bzq)2(acac)), tris(benzo[h]quinolinato)iridium (I II) (abbreviation: Ir(bzq)3), tris(2-phenylquinolinato-N,C 2’ )stomach Lithium(III) (abbreviation: Ir(pq)3), bis(2-phenylquinolinato-N,C 2’ ) Iridium(III) acetylacetonate (abbreviation: Ir(pq)2(acac) ), and organometallic iridium complexes with pyridine skeletons such as bis(2,4-diphenyl -1,3-Oxazolato-N,C 2’ ) Iridium(III) acetylacetonate (abbreviation Name: Ir(dpo)2(acac)), bis{2-[4'-(perfluorophenyl) fluorine Phenyl]pyridinato-N,C 2’}Iridium(III) acetylacetonate (abbreviation: Ir(p-PF-ph)2(acac)), bis(2-phenylbenzothiazolato-N, C 2’ ) Iridium(III) acetylacetonate (abbreviation: Ir(bt)2(acac In addition to organometallic iridium complexes such as tris(acetylacetonato)(monophenanthate), rare earth elements such as terbium(III) (abbreviated as Tb(acac)3(Phen)) Among the above, organometallic iridium complexes having a pyrimidine skeleton are Complexes are particularly preferred because they are remarkably excellent in reliability and luminous efficiency.

[0208] Furthermore, examples of substances having a yellow or red emission peak include (diisobutyryl) Methanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(II I) (abbreviation: Ir(5mdppm)2(dibm)), bis[4,6-bis(3-methyl [phenyl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: Ir (5mdppm)2(dpm)), bis[4,6-di(naphthalen-1-yl)pyrimidinyl] Nato](dipivaloylmethanato)iridium(III) (abbreviation: Ir(d1npm)2( Organometallic iridium complexes with pyrimidine skeletons, such as (acetylacetonyl acetone) Iridium(III) (abbreviation: I r(tppr)2(acac)), bis(2,3,5-triphenylpyrazinate)(dipyr Valoylmethanato)iridium(III) (abbreviation: Ir(tppr)2(dpm)), ( Acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]i Ir(Fdpq)2(acac) and other pyrazine-based compounds Organometallic iridium complexes and tris(1-phenylisoquinolinato-N,C 2’ ) Iridium(III) (abbreviation: Ir(piq)3), bis(1-phenylisoquinolinato) -N,C 2’ ) Iridium(III) acetylacetonate (abbreviation: Ir(piq)2( In addition to organometallic iridium complexes with pyridine skeletons such as acac), 2,3,7, 8,12,13,17,18-Octaethyl-21H,23H-porphyrin platinum(II) ) (abbreviation: PtOEP) and tris(1,3-diphenyl-1,3-propanediol). Eu(DB)(propanedionato)(monophenanthroline)europium(III) M)3(Phen)), tris[1-(2-thenoyl)-3,3,3-trifluoroacetate [Tonato](monophenanthroline)europium(III) (abbreviation: Eu(TTA)3( Among the above, rare earth metal complexes such as pyrimidine skeletons are Organometallic iridium complexes having the above structure are particularly preferred because they are remarkably excellent in reliability and luminous efficiency. In addition, organometallic iridium complexes with a pyrazine skeleton can emit red light with good chromaticity. can be done.

[0209] Furthermore, examples of substances having a blue or green emission peak include tris{2-[5 -(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-trimethylphenyl {riazol-3-yl-κN2]phenyl-κC}iridium(III) (abbreviation: Ir( mpptz-dmp)3), tris(5-methyl-3,4-diphenyl-4H-1,2, 4-triazolato)iridium(III) (abbreviation: Ir(Mptz)3), tris[4- (3-biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazola tris[3-(5 -biphenyl)-5-isopropyl-4-phenyl-4H-1,2,4-triazolato] Iridium(III) (abbreviation: Ir(iPr5btz)3), Organometallic iridium complexes with a methyl group skeleton and tris[3-methyl-1-(2-methylphenyl) (Nyl)-5-phenyl-1H-1,2,4-triazolato]iridium(III) (abbreviation :Ir(Mptz1-mp)3), tris(1-methyl-5-phenyl-3-propyl- 1H-1,2,4-triazolato)iridium(III) (abbreviation: Ir(PrPrtZl- Organometallic iridium complexes with 1H-triazole skeletons, such as Me)3), and fac -tris[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazoline Iridium(III) (abbreviation: Ir(iPrpmi)3), tris[3-(2,6- Dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium Ir(dmpimpt-Me)3) Organometallic iridium complexes and bis[2-(4',6'-difluorophenyl)pyridinium] Nat-N,C 2’ ]iridium(III) tetrakis(1-pyrazolyl)borate (abbreviation :FIr6), bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2’ ]iridium(III) picolinate (abbreviation: FIrpic), bis{2-[3',5' -bis(trifluoromethyl)phenyl]pyridinato-N,C 2’} Iridium (III ) picolinate (abbreviation: Ir(CF3ppy)2(pic)), bis[2-(4',6' (difluorophenyl)pyridinato-N,C 2’ ]Iridium(III) acetylacetonate Phenylpyridine derivatives bearing electron-withdrawing groups such as acetylacetate (abbreviation: FIr(acac)) Among the above, 4H-triazol-1-thiazolium complexes are organometallic iridium complexes with 4H-triazol-1-thiazolium as a ligand. Nitrogen-containing five-membered heterocycles such as azole skeletons, 1H-triazole skeletons, and imidazole skeletons The organometallic iridium complexes with the framework have high triplet excitation energy and are highly reliable and luminescent. This is particularly preferable because it also has excellent light efficiency.

[0210] In addition, among the organometallic iridium complexes having a nitrogen-containing five-membered heterocyclic skeleton, at least sialic acid is preferred. Iridium complexes with substituents containing cyano groups exhibit LUM due to the strong electron-withdrawing properties of the cyano groups. Since the O level and the HOMO level are lowered, the compound can be suitably used in the light-emitting element of one embodiment of the present invention. In addition, since the iridium complex has a high triplet excitation energy level, Therefore, by using the iridium complex in a light-emitting element, it is possible to obtain blue light emission with good luminous efficiency. In addition, the iridium complex is suitable for repeated oxidation and reduction. Since the iridium complex has excellent durability, the use of the iridium complex in a light-emitting element can improve the operating life. A good light-emitting element can be manufactured.

[0211] From the viewpoint of stability and reliability of device characteristics, a cyano group is added to the nitrogen-containing five-membered heterocyclic skeleton. Preferably, the iridium complex has a ligand to which an aryl group containing The number of carbon atoms in the alkyl group is preferably 6 to 13. In this case, the iridium complex is Since vacuum deposition can be performed at a relatively low temperature, deterioration such as thermal decomposition during deposition is unlikely to occur.

[0212] In addition, a cyano group is bonded to a nitrogen atom of the nitrogen-containing five-membered heterocyclic skeleton via an arylene group. Iridium complexes with linked ligands can maintain a high triplet excited energy level. Therefore, it can be suitably used for light emitting elements that emit high energy light, such as blue light. In addition, compared to those without cyano groups, they exhibit high-energy emission such as blue light. Furthermore, the introduction of a cyano group into such a specific position results in a highly efficient light-emitting device. By doing so, it is possible to obtain a highly reliable light-emitting element that emits high-energy light such as blue light. It should be noted that there is a phenanthroline bond between the nitrogen-containing five-membered heterocyclic skeleton and the cyano group. Attachment via an arylene group such as an nylene group is preferred.

[0213] When the arylene group has 6 to 13 carbon atoms, the iridium complex is Since it is a compound with a relatively low molecular weight, it is suitable for vacuum deposition (a compound that can be vacuum deposited at a relatively low temperature). Generally, when the molecular weight is low, the heat resistance after film formation is poor. The iridium complex has multiple ligands, so it has sufficient heat resistance even if the molecular weight of the ligands is low. This has the advantage of ensuring reliability.

[0214] That is, the iridium complex has the following advantages in addition to the ease of deposition and electrochemical stability described above: The triplet excitation energy level of the compound of the present invention is high. In a light-emitting element, the iridium complex is preferably used as a guest material in a light-emitting layer. Among these, it is particularly suitable for use as a guest material in a blue light-emitting device.

[0215] <Examples of iridium complexes> The iridium complex is represented by the following general formula (G11).

[0216] [ka]

[0217] In the above general formula (G11), Ar 11 and Ar 12 are each independently a group having 6 carbon atoms The aryl group having 6 to 13 carbon atoms is a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. Specific examples of the alkyl group include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. When the aryl group has a substituent, the substituent may be an alkyl group having 1 or more carbon atoms. an alkyl group having from 1 to 6 carbon atoms, a cycloalkyl group having from 3 to 6 carbon atoms, or a substituted alkyl group having from 6 to 13 carbon atoms; Alternatively, an unsubstituted aryl group can also be selected as a substituent. Specific examples of alkyl groups include methyl, ethyl, propyl, isopropyl, and butyl groups. Examples of the alkyl group include an isobutyl group, a tert-butyl group, and an n-hexyl group. Specific examples of the cycloalkyl group having 3 to 6 carbon atoms include a cyclopropyl group, ... Examples of the alkyl group include a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group. Examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, a naphthyl group, a biphenyl group, a fluoro group, and the like. A specific example is an oleyl group.

[0218] Also, Q 1 and Q 2 each independently represents N or CR, and R represents hydrogen, the number of carbon atoms, an alkyl group having 1 to 6 carbon atoms, a haloalkyl group having 1 to 6 carbon atoms, or a group having 6 to 13 carbon atoms; represents a substituted or unsubstituted aryl group. 1 and Q 2 At least one of the following is CR Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, and a propyl group. propyl, isopropyl, butyl, isobutyl, tert-butyl, n-hexyl In addition, examples of the haloalkyl group having 1 to 6 carbon atoms include at least At least one hydrogen atom is replaced by a group 17 element (fluorine, chlorine, bromine, iodine, astatine) Substituted alkyl groups, such as alkyl fluorides, alkyl chlorides, and alkyl bromides; Examples of the alkyl iodide include methyl fluoride, methyl chloride, and fluoride. ethyl group, ethyl chloride group, etc., but the number of halogen atoms contained or The type of each may be one or more. Specific examples of the group include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. Furthermore, the aryl group may have a substituent, and the substituent The groups may be bonded to each other to form a ring. The substituents include alkyl groups having 1 to 6 carbon atoms. A cycloalkyl group having 3 to 6 carbon atoms, or an aryl group having 6 to 13 carbon atoms may also be substituted. Specific examples of alkyl groups having 1 to 6 carbon atoms include methyl groups. propyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl Examples of the cycloalkyl group include a cycloalkyl group having 3 to 6 carbon atoms, an n-ethyl group, and an n-hexyl group. Specific examples of alkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, and cyclopentyl groups. Examples of the aryl group having 6 to 13 carbon atoms include a cyclohexyl group and the like. Specific examples of the alkyl group include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. It is possible.

[0219] Also, Ar 11 and Ar 12 and an aryl group represented by R The other has a cyano group.

[0220] In addition, examples of iridium complexes that can be suitably used in the light-emitting element of one embodiment of the present invention include The iridium complex is preferably an orthometal complex. It is an iridium complex represented by the formula:

[0221] [ka]

[0222] In the above general formula (G12), Ar 11 is a substituted or unsubstituted alkyl group having 6 to 13 carbon atoms. The aryl group having 6 to 13 carbon atoms includes a phenyl group, a naphthyl group, Specific examples include a biphenyl group and a fluorenyl group. When the group has a substituent, the substituent is an alkyl group having 1 to 6 carbon atoms, a group having 3 or more carbon atoms, or a cycloalkyl group having 6 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms; Specific examples of alkyl groups having 1 to 6 carbon atoms include: Methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert n-butyl group, n-hexyl group, etc. Also, cycloalkyl groups having 3 to 6 carbon atoms can be used. Specific examples of the alkyl group include a cyclopropyl group, a cyclobutyl group, and a cyclopentyl group. and cyclohexyl groups. Also, aryl groups having 6 to 13 carbon atoms are suitable. Specific examples of the alkyl group include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. Some examples include:

[0223] Also, R 31 ~R 34 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a carbon atom, a cycloalkyl group having 3 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms; or a cyano group. Specific examples of the alkyl group having 1 to 6 carbon atoms include: Methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert n-butyl group, n-hexyl group, etc. Also, cycloalkyl groups having 3 to 6 carbon atoms can be used. Specific examples of the alkyl group include a cyclopropyl group, a cyclobutyl group, and a cyclopentyl group. and cyclohexyl groups. Also, aryl groups having 6 to 13 carbon atoms are suitable. Specific examples of the alkyl group include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. In addition, R 31 ~R 34 The fact that all of the is hydrogen makes it easier to synthesize This is advantageous in terms of the cost of raw materials.

[0224] Also, Q 1 and Q 2 each independently represents N or CR, and R represents hydrogen, the number of carbon atoms, an alkyl group having 1 to 6 carbon atoms, a haloalkyl group having 1 to 6 carbon atoms, or a group having 6 to 13 carbon atoms; represents a substituted or unsubstituted aryl group. 1 and Q 2 At least one of the following is CR Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, and a propyl group. propyl, isopropyl, butyl, isobutyl, tert-butyl, n-hexyl In addition, examples of the haloalkyl group having 1 to 6 carbon atoms include at least At least one hydrogen atom is replaced by a group 17 element (fluorine, chlorine, bromine, iodine, astatine) Substituted alkyl groups, such as alkyl fluorides, alkyl chlorides, and alkyl bromides; Examples of the alkyl iodide include methyl fluoride, methyl chloride, and fluoride. ethyl group, ethyl chloride group, etc., but the number of halogen atoms contained or The type of each may be one or more. Specific examples of the group include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. Furthermore, the aryl group may have a substituent, and the substituent The groups may be bonded to each other to form a ring. The substituents include alkyl groups having 1 to 6 carbon atoms. A cycloalkyl group having 3 to 6 carbon atoms, or an aryl group having 6 to 13 carbon atoms may also be substituted. Specific examples of alkyl groups having 1 to 6 carbon atoms include methyl groups. propyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl Examples of the cycloalkyl group include a cycloalkyl group having 3 to 6 carbon atoms, an n-ethyl group, and an n-hexyl group. Specific examples of alkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, and cyclopentyl groups. Examples of the aryl group having 6 to 13 carbon atoms include a cyclohexyl group and the like. Specific examples of the alkyl group include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. It is possible.

[0225] Also, Ar 11 and R 31 ~R 34 an aryl group represented by R, and an aryl group represented by R 31 ~R 34 At least one of them has a cyano group.

[0226] In addition, in an iridium complex that can be suitably used for the light-emitting element of one embodiment of the present invention, The 4H-triazole skeleton of the benzophenone-1 has a high triplet excitation energy level. This is particularly suitable for light-emitting elements that emit high-energy light such as blue light. The iridium complex is preferably represented by the following general formula (G13): It is an iridium complex.

[0227] [ka]

[0228] In the above general formula (G13), Ar 11 is a substituted or unsubstituted alkyl group having 6 to 13 carbon atoms. The aryl group having 6 to 13 carbon atoms includes a phenyl group, a naphthyl group, Specific examples include a biphenyl group and a fluorenyl group. When the group has a substituent, the substituent is an alkyl group having 1 to 6 carbon atoms, a group having 3 or more carbon atoms, or a cycloalkyl group having 6 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms; Specific examples of alkyl groups having 1 to 6 carbon atoms include: Methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert n-butyl group, n-hexyl group, etc. Also, cycloalkyl groups having 3 to 6 carbon atoms can be used. Specific examples of the alkyl group include a cyclopropyl group, a cyclobutyl group, and a cyclopentyl group. and cyclohexyl groups. Also, aryl groups having 6 to 13 carbon atoms are suitable. Specific examples of the alkyl group include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. Some examples include:

[0229] Also, R 31 ~R 34 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a carbon atom, a cycloalkyl group having 3 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms; or a cyano group. Specific examples of the alkyl group having 1 to 6 carbon atoms include: Methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert n-butyl group, n-hexyl group, etc. Also, cycloalkyl groups having 3 to 6 carbon atoms can be used. Specific examples of the alkyl group include a cyclopropyl group, a cyclobutyl group, and a cyclopentyl group. and cyclohexyl groups. Also, aryl groups having 6 to 13 carbon atoms are suitable. Specific examples of the alkyl group include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. In addition, R 31 ~R 34 The fact that all of the is hydrogen makes it easier to synthesize This is advantageous in terms of the cost of raw materials.

[0230] Also, R 35 represents hydrogen, an alkyl group having 1 to 6 carbon atoms, or a haloalkyl group having 1 to 6 carbon atoms. group, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. Specific examples of alkyl groups having 1 to 6 include methyl, ethyl, propyl, and isopropyl groups. Examples include propyl, butyl, isobutyl, tert-butyl, and n-hexyl groups. The haloalkyl group having 1 to 6 carbon atoms may be selected from the group consisting of at least one hydrogen atom, Al in which the atoms are replaced by elements of group 17 (fluorine, chlorine, bromine, iodine, astatine) alkyl groups, such as alkyl fluorides, alkyl chlorides, alkyl bromides, and alkyl iodides; Specific examples include methyl fluoride groups, methyl chloride groups, ethyl fluoride groups, and chloride groups. The number or type of halogen atoms contained in each group varies. The aryl group having 6 to 13 carbon atoms may be a fluoro group. Specific examples include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. Furthermore, the aryl group may have substituents, and the substituents may be bonded to each other. The substituent may be an alkyl group having 1 to 6 carbon atoms, a group having 3 carbon atoms, or a group having 4 to 6 carbon atoms. A cycloalkyl group having 6 to 6 carbon atoms or an aryl group having 6 to 13 carbon atoms may also be selected as a substituent. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group and an ethyl group. , propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, n-butyl group Examples of cycloalkyl groups having 3 to 6 carbon atoms include: Specifically, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group Examples of the aryl group having 6 to 13 carbon atoms include a phenyl group. Specific examples include a naphthyl group, a biphenyl group, and a fluorenyl group.

[0231] Also, Ar 11 and R 31 ~R 35 and an aryl group represented by R 31 ~R 34 Few At least one of them has a cyano group.

[0232] In addition, in an iridium complex that can be suitably used for the light-emitting element of one embodiment of the present invention, has a high triplet excited energy level due to the imidazole skeleton as a ligand. It can be used particularly suitably for light emitting elements that emit high energy light such as blue light. The iridium complex is preferably represented by the following general formula (G14): It is an iridium complex.

[0233] [ka]

[0234] In the above general formula (G14), Ar 11 is a substituted or unsubstituted alkyl group having 6 to 13 carbon atoms. The aryl group having 6 to 13 carbon atoms includes a phenyl group, a naphthyl group, Specific examples include a biphenyl group and a fluorenyl group. When the group has a substituent, the substituent is an alkyl group having 1 to 6 carbon atoms, a group having 3 or more carbon atoms, or a cycloalkyl group having 6 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms; Specific examples of alkyl groups having 1 to 6 carbon atoms include: Methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert n-butyl group, n-hexyl group, etc. Also, cycloalkyl groups having 3 to 6 carbon atoms can be used. Specific examples of the alkyl group include a cyclopropyl group, a cyclobutyl group, and a cyclopentyl group. and cyclohexyl groups. Also, aryl groups having 6 to 13 carbon atoms are suitable. Specific examples of the alkyl group include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. Some examples include:

[0235] Also, R 31 ~R 34 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a carbon atom, a cycloalkyl group having 3 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms; Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, Ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group and n-hexyl groups. Also, cycloalkyl groups having 3 to 6 carbon atoms are suitable. Specific examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl ... Examples of the aryl group having 6 to 13 carbon atoms include: Specific examples include phenyl, naphthyl, biphenyl, and fluorenyl groups. In addition, R 31 ~R 34 The fact that all of the compound is hydrogen makes it easier to synthesize and more cost-effective to use as raw materials. It is advantageous in terms of rank.

[0236] Also, R 35 and R 36 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a carbon atom, a haloalkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms; Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethylene group, and an ethylene group. butyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, n-hexyl groups, etc. Also, haloalkyl groups having 1 to 6 carbon atoms, At least one hydrogen atom is attached to a group 17 element (fluorine, chlorine, bromine, iodine, astatine, etc.). alkyl groups substituted with alkyl fluorides, alkyl chlorides, and alkyl bromides; Examples include alkyl groups, iodinated alkyl groups, and the like. Specifically, methyl fluoride groups, methyl chloride groups, Examples of halogen groups include ethyl fluoride groups, ethyl chloride groups, etc. The number or type of atoms may be one or more. The aryl group of 3 includes a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, etc. Specific examples include the following. Furthermore, the aryl group may have a substituent. The substituents may be bonded to each other to form a ring. an alkyl group having from 3 to 6 carbon atoms, a cycloalkyl group having from 3 to 6 carbon atoms, or an aryl group having from 6 to 13 carbon atoms; A alkyl group having 1 to 6 carbon atoms can also be selected as a substituent. Specifically, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl group, n-hexyl group, etc. Specific examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclopentyl group. Examples of the alkyl group include aryl groups having 6 to 13 carbon atoms, such as butyl groups and cyclohexyl groups. Specific examples of the alkyl group include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. It can be mentioned as follows.

[0237] Also, Ar 11 and R 31 ~R 36 an aryl group represented by R 31 ~R 34 At least The other has a cyano group.

[0238] In addition, in an iridium complex that can be suitably used for the light-emitting element of one embodiment of the present invention, The aryl group bonded to the nitrogen atom of the nitrogen-containing five-membered heterocyclic skeleton is a substituted or unsubstituted phenyl. In the case of a group, vacuum deposition can be performed at a relatively low temperature, and the triplet excitation energy level is high, Therefore, it can be suitably used in light-emitting elements that emit high-energy light, such as blue light. The iridium complex is preferably an iridium complex represented by the following general formulas (G15) and (G16): It is a nium complex.

[0239] [ka]

[0240] In the above general formula (G15), R 37 and R 41 represents an alkyl group having 1 to 6 carbon atoms. represents R 37 and R 41 have the same structure. As an alkyl group having 1 to 6 carbon atoms, Specifically, the alkyl group includes a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, and the like. Examples of the alkyl group include an aryl group, a tert-butyl group, and an n-hexyl group.

[0241] Also, R 38 ~R 40 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a carbon atom, a cycloalkyl group having 3 to 6 prime numbers, a substituted or unsubstituted phenyl group, or a cyano group Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group and an ethyl group. , propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, n-butyl group Examples of cycloalkyl groups having 3 to 6 carbon atoms include cycloalkyl groups such as cyclohexyl groups and cyclohexyl groups. Specifically, the cyclopropyl group, the cyclobutyl group, the cyclopentyl group, the cyclohexyl group, groups. 38 ~R 40 At least one of the groups has a cyano group. It is preferable to do so.

[0242] Also, R 31 ~R 34 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a carbon atom, a cycloalkyl group having 3 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms; Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, Ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group and n-hexyl groups. Also, cycloalkyl groups having 3 to 6 carbon atoms are suitable. Specific examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl ... Examples of the aryl group having 6 to 13 carbon atoms include: Specific examples include phenyl, naphthyl, biphenyl, and fluorenyl groups. In addition, R 31 ~R 34 The fact that all of the compound is hydrogen makes it easier to synthesize and more cost-effective to use as raw materials. It is advantageous in terms of rank.

[0243] Also, R 35 represents hydrogen, an alkyl group having 1 to 6 carbon atoms, or a haloalkyl group having 1 to 6 carbon atoms. group, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. Specific examples of alkyl groups having 1 to 6 include methyl, ethyl, propyl, and isopropyl groups. Examples include propyl, butyl, isobutyl, tert-butyl, and n-hexyl groups. The haloalkyl group having 1 to 6 carbon atoms may be selected from the group consisting of at least one hydrogen atom, Al in which the atoms are replaced by elements of group 17 (fluorine, chlorine, bromine, iodine, astatine) alkyl groups, such as alkyl fluorides, alkyl chlorides, alkyl bromides, and alkyl iodides; Specific examples include methyl fluoride groups, methyl chloride groups, ethyl fluoride groups, and chloride groups. The number or type of halogen atoms contained in each group varies. The aryl group having 6 to 13 carbon atoms may be a fluoro group. Specific examples include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. Furthermore, the aryl group may have substituents, and the substituents may be bonded to each other. The substituent may be an alkyl group having 1 to 6 carbon atoms, a group having 3 carbon atoms, or a group having 4 to 6 carbon atoms. A cycloalkyl group having 6 to 6 carbon atoms or an aryl group having 6 to 13 carbon atoms may also be selected as a substituent. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group and an ethyl group. , propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, n-butyl group Examples of cycloalkyl groups having 3 to 6 carbon atoms include: Specifically, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group Examples of the aryl group having 6 to 13 carbon atoms include a phenyl group. Specific examples include a naphthyl group, a biphenyl group, and a fluorenyl group.

[0244] [ka]

[0245] In the above general formula (G16), R 37 and R 41 represents an alkyl group having 1 to 6 carbon atoms. represents R 37 and R 41 have the same structure. As an alkyl group having 1 to 6 carbon atoms, Specifically, the alkyl group includes a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, and the like. Examples of the alkyl group include an aryl group, a tert-butyl group, and an n-hexyl group.

[0246] R 38 ~R 40 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, or a group having 3 carbon atoms. any one of the cycloalkyl groups of the formulas 1 to 6, a substituted or unsubstituted phenyl group, or a cyano group; Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, and a propyl group. propyl, isopropyl, butyl, isobutyl, tert-butyl, n-hexyl Examples of the cycloalkyl group having 3 to 6 carbon atoms include: Examples include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group. In addition, R 38 ~R 40 At least one of them has a cyano group. It is preferable that:

[0247] Also, R 31 ~R 34 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a carbon atom, a cycloalkyl group having 3 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms; Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, Ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group and n-hexyl groups. Also, cycloalkyl groups having 3 to 6 carbon atoms are suitable. Specific examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl ... Examples of the aryl group having 6 to 13 carbon atoms include: Specific examples include phenyl, naphthyl, biphenyl, and fluorenyl groups. In addition, R 31 ~R 34 The fact that all of the compound is hydrogen makes it easier to synthesize and more cost-effective to use as raw materials. It is advantageous in terms of rank.

[0248] Also, R 35 and R 36 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a carbon atom, a haloalkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms; Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethylene group, and an ethylene group. butyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, n-hexyl groups, etc. Also, haloalkyl groups having 1 to 6 carbon atoms, At least one hydrogen atom is attached to a group 17 element (fluorine, chlorine, bromine, iodine, astatine, etc.). alkyl groups substituted with alkyl fluorides, alkyl chlorides, and alkyl bromides; Examples include alkyl groups, iodinated alkyl groups, and the like. Specifically, methyl fluoride groups, methyl chloride groups, Examples of halogen groups include ethyl fluoride groups, ethyl chloride groups, etc. The number or type of atoms may be one or more. The aryl group of 3 includes a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, etc. Specific examples include the following. Furthermore, the aryl group may have a substituent. The substituents may be bonded to each other to form a ring. an alkyl group having from 3 to 6 carbon atoms, a cycloalkyl group having from 3 to 6 carbon atoms, or an aryl group having from 6 to 13 carbon atoms; A alkyl group having 1 to 6 carbon atoms can also be selected as a substituent. Specifically, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl group, n-hexyl group, etc. Specific examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclopentyl group. Examples of the alkyl group include aryl groups having 6 to 13 carbon atoms, such as butyl groups and cyclohexyl groups. Specific examples of the alkyl group include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. It can be mentioned as follows.

[0249] In addition, in an iridium complex that can be suitably used for the light-emitting element of one embodiment of the present invention, The 1H-triazole skeleton of the benzophenone-1 has a high triplet excitation energy level. Since it can have a position, it is particularly suitable for light-emitting elements that emit high energy light such as blue light. The iridium complex is preferably represented by the following general formula (G17): ) and (G18).

[0250] [ka]

[0251] In the above general formula (G17), Ar 11 is a substituted or unsubstituted alkyl group having 6 to 13 carbon atoms. The aryl group having 6 to 13 carbon atoms includes a phenyl group, a naphthyl group, Specific examples include a biphenyl group and a fluorenyl group. When the group has a substituent, the substituent is an alkyl group having 1 to 6 carbon atoms, a group having 3 or more carbon atoms, or a cycloalkyl group having 6 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms; Specific examples of alkyl groups having 1 to 6 carbon atoms include: Methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert n-butyl group, n-hexyl group, etc. Also, cycloalkyl groups having 3 to 6 carbon atoms can be used. Specific examples of the alkyl group include a cyclopropyl group, a cyclobutyl group, and a cyclopentyl group. and cyclohexyl groups. Also, aryl groups having 6 to 13 carbon atoms are suitable. Specific examples of the alkyl group include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. Some examples include:

[0252] Also, R 31 ~R 34 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a carbon atom, a cycloalkyl group having 3 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms; Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, Ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group and n-hexyl groups. Also, cycloalkyl groups having 3 to 6 carbon atoms are suitable. Specific examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl ... Examples of the aryl group having 6 to 13 carbon atoms include: Specific examples include phenyl, naphthyl, biphenyl, and fluorenyl groups. In addition, R 31 ~R 34 The fact that all of the compound is hydrogen makes it easier to synthesize and more cost-effective to use as raw materials. It is advantageous in terms of rank.

[0253] Also, R 36 represents hydrogen, an alkyl group having 1 to 6 carbon atoms, or a haloalkyl group having 1 to 6 carbon atoms. group, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. Specific examples of alkyl groups having 1 to 6 include methyl, ethyl, propyl, and isopropyl groups. Examples include propyl, butyl, isobutyl, tert-butyl, and n-hexyl groups. The haloalkyl group having 1 to 6 carbon atoms may be selected from the group consisting of at least one hydrogen atom, Al in which the atoms are replaced by elements of group 17 (fluorine, chlorine, bromine, iodine, astatine) alkyl groups, such as alkyl fluorides, alkyl chlorides, alkyl bromides, and alkyl iodides; Specific examples include methyl fluoride groups, methyl chloride groups, ethyl fluoride groups, and chloride groups. The number or type of halogen atoms contained in each group varies. The aryl group having 6 to 13 carbon atoms may be a fluoro group. Specific examples include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. Furthermore, the aryl group may have substituents, and the substituents may be bonded to each other. The substituent may be an alkyl group having 1 to 6 carbon atoms, a group having 3 carbon atoms, or a group having 4 to 6 carbon atoms. A cycloalkyl group having 6 to 6 carbon atoms or an aryl group having 6 to 13 carbon atoms may also be selected as a substituent. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group and an ethyl group. , propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, n-butyl group Examples of cycloalkyl groups having 3 to 6 carbon atoms include: Specifically, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group Examples of the aryl group having 6 to 13 carbon atoms include a phenyl group. Specific examples include a naphthyl group, a biphenyl group, and a fluorenyl group.

[0254] Also, Ar 11 , R 31 ~R 34 , and R 36 and an aryl group represented by R 31 ~R 34 At least one of them has a cyano group.

[0255] [ka]

[0256] In the above general formula (G18), R 37 and R 41 represents an alkyl group having 1 to 6 carbon atoms. represents R 37 and R 41 have the same structure. As an alkyl group having 1 to 6 carbon atoms, Specifically, the alkyl group includes a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, and the like. Examples of the alkyl group include an aryl group, a tert-butyl group, and an n-hexyl group.

[0257] Also, R 38 ~R 40 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a carbon atom, a cycloalkyl group having 3 to 6 prime numbers, a substituted or unsubstituted phenyl group, or a cyano group Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group and an ethyl group. , propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, n-butyl group Examples of cycloalkyl groups having 3 to 6 carbon atoms include cycloalkyl groups such as cyclohexyl groups and cyclohexyl groups. Specifically, the cyclopropyl group, the cyclobutyl group, the cyclopentyl group, the cyclohexyl group, groups. 38 ~R 40 At least one of the groups has a cyano group. It is preferable to do so.

[0258] Also, R 31 ~R 34 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a carbon atom, a cycloalkyl group having 3 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms; Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, Ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group and n-hexyl groups. Also, cycloalkyl groups having 3 to 6 carbon atoms are suitable. Specific examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl ... Examples of the aryl group having 6 to 13 carbon atoms include: Specific examples include phenyl, naphthyl, biphenyl, and fluorenyl groups. In addition, R 31 ~R 34 The fact that all of the compound is hydrogen makes it easier to synthesize and more cost-effective to use as raw materials. It is advantageous in terms of rank.

[0259] Also, R 36 represents hydrogen, an alkyl group having 1 to 6 carbon atoms, or a haloalkyl group having 1 to 6 carbon atoms. group, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. Specific examples of alkyl groups having 1 to 6 include methyl, ethyl, propyl, and isopropyl groups. Examples include propyl, butyl, isobutyl, tert-butyl, and n-hexyl groups. The haloalkyl group having 1 to 6 carbon atoms may be selected from the group consisting of at least one hydrogen atom, Al in which the atoms are replaced by elements of group 17 (fluorine, chlorine, bromine, iodine, astatine) alkyl groups, such as alkyl fluorides, alkyl chlorides, alkyl bromides, and alkyl iodides; Specific examples include methyl fluoride groups, methyl chloride groups, ethyl fluoride groups, and chloride groups. The number or type of halogen atoms contained in each group varies. The aryl group having 6 to 13 carbon atoms may be a fluoro group. Specific examples include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. Furthermore, the aryl group may have substituents, and the substituents may be bonded to each other. The substituent may be an alkyl group having 1 to 6 carbon atoms, a group having 3 carbon atoms, or a group having 4 to 6 carbon atoms. A cycloalkyl group having 6 to 6 carbon atoms or an aryl group having 6 to 13 carbon atoms may also be selected as a substituent. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group and an ethyl group. , propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, n-butyl group Examples of cycloalkyl groups having 3 to 6 carbon atoms include: Specifically, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group Examples of the aryl group having 6 to 13 carbon atoms include a phenyl group. Specific examples include a naphthyl group, a biphenyl group, and a fluorenyl group.

[0260] R in the above general formulae (G12) to (G18) 31 ~R 34 and an alkyl group represented by The aryl group may be, for example, a group represented by the above structural formulas (R-1) to (R-29). The groups that can be used as the alkyl group and the aryl group are as follows: Not limited to.

[0261] In addition, in the general formulae (G11) to (G14) and (G17), Ar 11 Expressed as and in general formula (G11), Ar 12 The aryl group represented by For example, groups represented by the above structural formulas (R-12) to (R-29) can be used. It is possible. 11 and Ar 12 The groups that can be used as are not limited to these. .

[0262] In addition, R in general formulae (G15), (G16), and (G18)37 and R 41 is expressed as The alkyl group may be, for example, a group represented by the above structural formulas (R-1) to (R-10). However, the groups that can be used as the alkyl group are not limited to these.

[0263] In addition, R in general formulae (G15), (G16), and (G18) 38 ~R 40 is expressed as The alkyl group or the substituted or unsubstituted phenyl group may be, for example, a group represented by the above structural formula (R-1) to A group represented by (R-22) can be used. In addition, an alkyl group or a phenyl group The groups that can be used as are not limited to these.

[0264] In addition, R in the above general formulas (G13) to (G16) 35 and general formula (G14), (G1 6) to (G18) R 36 an alkyl group, an aryl group, or a haloalkyl group represented by the formula: are, for example, the above structural formulas (R-1) to (R-29) and the following structural formulas (R-30) to (R-31). A group represented by (R-37) can be applied. In addition, an alkyl group, an aryl group, or The groups that can be used as the haloalkyl group are not limited to these.

[0265] [ka]

[0266] <Specific examples of iridium complexes> Specific structures of iridium complexes represented by the above general formulas (G11) to (G18) Examples include compounds represented by the following structural formulas (500) to (534). The iridium complexes represented by the general formulae (G11) to (G18) are not limited to the following examples. stomach.

[0267] [ka]

[0268] [ka]

[0269] [ka]

[0270] [ka]

[0271] [ka]

[0272] [ka]

[0273] As described above, the iridium complexes exemplified above have relatively low HOMO levels and LU Since the compound has an MO level, it is suitable as a guest material for the light-emitting element of one embodiment of the present invention. This makes it possible to manufacture a light-emitting element with good luminous efficiency. Iridium complexes have a high triplet excited energy level, making them particularly suitable for blue light-emitting elements. This makes it possible to fabricate blue light-emitting devices with good luminous efficiency. In addition, the iridium complexes exemplified above are suitable for repeated oxidation and reduction. Since the iridium complex has good resistance, the use of the iridium complex in a light-emitting element can improve the operating life. A good light-emitting device can be fabricated.

[0274] The light-emitting material contained in the light-emitting layer 130 and the light-emitting layer 135 is a triplet excited energy Any material capable of converting triplet excitation energy into luminescence may be used. In addition to phosphorescent materials, thermally activated delayed fluorescent materials can also be used. The term "optical material" may be read as "thermally activated delayed fluorescent material."

[0275] <Host Material 133> The host material 133 has a LUMO level higher than that of the host material 132. and a host material 132 having a HOMO level lower than the HOMO level of the host material 132. It is preferable to select the luminescent material 133 and the host material 132. This results in high luminous efficiency. In this case, a light-emitting element that can be driven at a low voltage can be obtained. The materials exemplified as the stock material 132 may also be used.

[0276] As the host material 133, a material having a higher electron transporting property than a hole transporting property can be used. 1×10 -6 cm 2 It is preferable that the material has an electron mobility of .beta. / Vs or more. As materials that are easy to accept (materials with electron transport properties), nitrogen-containing heteroaromatic compounds are Compounds with π-electron-deficient heteroaromatic ring skeletons, such as zinc and aluminum metal complexes, Specifically, quinoline ligands, benzoquinoline ligands, oxa Metal complexes with zole or thiazole ligands, and oxadiazole derivatives , triazole derivatives, benzimidazole derivatives, quinoxaline derivatives, dibenzoquinoline Xaline derivatives, phenanthroline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidinone derivatives Examples of compounds include azine derivatives and triazine derivatives.

[0277] Specifically, for example, tris(8-quinolinolato)aluminum(III) (abbreviation: A lq), tris(4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Al mq3), bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation :BeBq2), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)a Aluminum(III) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Metal complexes having a quinoline skeleton or a benzoquinoline skeleton, such as Znq, In addition, bis[2-(2-benzoxazolyl)phenolato]zinc(II)( Abbreviation: ZnPBO), bis[2-(2-benzothiazolyl)phenolato]zinc(II) ( Metal complexes with oxazole or thiazole ligands, such as ZnBTZ In addition to metal complexes, 2-(4-biphenylyl)-5 -(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD) and 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazo OXD-7), 9-[4-(5-phenyl-1,3, 4-Oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation: CO11) , 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)- 1,2,4-Triazole (abbreviation: TAZ), 9-[4-(4,5-diphenyl-4H- 1,2,4-triazol-3-yl)phenyl]-9H-carbazole (abbreviation: CzT AZ1), 2,2',2''-(1,3,5-benzenetriyl)tris(1-phenyl -1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophene- 4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBI m-II), bathophenanthroline (abbreviation: BPhen), bathocuproine (abbreviation: B Heterocyclic compounds such as 2-[3-(dibenzothiophen-4-yl)phenyl] Dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-( Dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxalate (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazole-9-yl) 2mCzBPDB q), 2-[4-(3,6-diphenyl-9H-carbazol-9-yl)phenyl]di Benzo[f,h]quinoxaline (abbreviation: 2CzPDBq-III), 7-[3-(dibenzo[f,h]quinoxaline] [4-( ... TPDBq-II) and 6-[3-(dibenzothiophen-4-yl)phenyl]di Benzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II), 2-[3-(3, 9'-bi-9H-carbazol-9-yl)phenyl]dibenzo[f,h]quinoxaline (Abbreviation: 2mCzCzPDBq), 4,6-bis[3-(phenanthrene-9-yl)phenyl] phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(4-diphenyl)pyrimidine 4,6-zothienyl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), Bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mC Heterocyclic compounds with diazine skeletons such as 2-{4-[3-(N-phenyl)-2-(4 ... (9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}- Triazines such as 4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn) Heterocyclic compounds with an amine skeleton and 3,5-bis[3-(9H-carbazol-9-yl] )phenyl]pyridine (abbreviation: 35DCzPPy), 1,3,5-tri[3-(3-pyridinyl) Heterocyclization of pyridine skeletons such as [(phenyl)phenyl]benzene (abbreviation: TmPyPB) Compound, 4,4'-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: Heteroaromatic compounds such as BzOs can also be used. The triazine skeleton, diazine (pyrimidine, pyrazine, pyridazine) skeleton, or pyridazine skeleton Heterocyclic compounds having an azine skeleton are preferred because they are stable and highly reliable. Heterocyclic compounds having the above structure have high electron transport properties and contribute to reducing the driving voltage. 2,5-pyridinediyl) (abbreviation: PPy), poly[(9,9-dihexylfluorene- 2,7-diyl)-co-(pyridine-3,5-diyl)] (abbreviation: PF-Py), poly [(9,9-dioctylfluorene-2,7-diyl)-co-(2,2'-bipyridine Polymer compounds such as PF-BPy (PF-6,6'-diyl) can also be used. The substances mentioned here are mainly 1×10 -6 cm 2 / Vs or higher electron mobility It should be noted that any substance other than those mentioned above that has a higher electron transporting property than holes can be used. It's okay.

[0278] As the host material 133, the following hole transporting materials can be used.

[0279] As the hole transporting material, a material having a higher hole transporting property than an electron transporting property can be used. x10 -6 cm 2 It is preferable that the material has a hole mobility of 1 / Vs or more. The compounds are prepared using aromatic amines, carbazole derivatives, aromatic hydrocarbons, stilbene derivatives, etc. The hole transporting material may be a polymer compound.

[0280] As the material having high hole transporting properties, specifically, aromatic amine compounds such as N, N'-Di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviated as DT DPPA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenyla N,N'-bis[4-[bis(3-methylphenyl) {N,N'-diphenyl-(1,1'-biphenyl)-4,4' -diamine (abbreviation: DNTPD), 1,3,5-tris[N-(4-diphenylamino) [phenyl]-N-phenylamino]benzene (abbreviation: DPA3B), etc. .

[0281] Specific examples of carbazole derivatives include 3-[N-(4-diphenylamino phenyl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzDPA1 ), 3,6-bis[N-(4-diphenylaminophenyl)-N-phenylamino]-9 -phenylcarbazole (abbreviation: PCzDPA2), 3,6-bis[N-(4-diphenyl [N-(1-naphthyl)amino]-9-phenylcarbazole (abbreviation :PCzTPN2), 3-[N-(9-phenylcarbazol-3-yl)-N-phenyl 3,6-bis[N- (9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazol PCzPCA2, 3-[N-(1-naphthyl)-N-(9-phenylcarbazone] [carbazol-3-yl]amino]-9-phenylcarbazole (abbreviation: PCzPCN1) The following can be mentioned:

[0282] Other carbazole derivatives include 4,4'-di(N-carbazolyl)biphene. Nyl (abbreviation: CBP), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzoyl Zene (abbreviation: TCPB), 9-[4-(10-phenyl-9-anthryl)phenyl]- 9H-Carbazole (abbreviation: CzPA), 1,4-bis[4-(N-carbazolyl)phenyl] nyl]-2,3,5,6-tetraphenylbenzene, etc. can be used.

[0283] Furthermore, examples of aromatic hydrocarbons include 2-tert-butyl-9,10-di(2- naphthyl)anthracene (abbreviation: t-BuDNA), 2-tert-butyl-9,10- Di(1-naphthyl)anthracene, 9,10-bis(3,5-diphenylphenyl)anthracene thracene (abbreviation: DPPA), 2-tert-butyl-9,10-bis(4-phenylphenyl) phenyl)anthracene (abbreviation: t-BuDBA), 9,10-di(2-naphthyl)anthracene Helical anthracene (abbreviated as DNA), 9,10-diphenylanthracene (abbreviated as DPAnth), 2-tert-butylanthracene (abbreviation: t-BuAnth), 9,10-bis(4- Methyl-1-naphthyl)anthracene (abbreviation: DMNA), 2-tert-butyl-9, 10-bis[2-(1-naphthyl)phenyl]anthracene, 9,10-bis[2-(1 -naphthyl)phenyl]anthracene, 2,3,6,7-tetramethyl-9,10-di( 1-naphthyl)anthracene, 2,3,6,7-tetramethyl-9,10-di(2-naphthyl)anthracene thyl)anthracene, 9,9'-bianthryl, 10,10'-diphenyl-9,9'- Bianthryl, 10,10'-bis(2-phenylphenyl)-9,9'-bianthryl , 10,10'-bis[(2,3,4,5,6-pentaphenyl)phenyl]-9,9' -Bianthryl, anthracene, tetracene, rubrene, perylene, 2,5,8,11- tetra(tert-butyl)perylene, etc. In addition, pentacene, Years etc. can also be used. In this way, 1 × 10 -6 cm 2 Hole mobility above / Vs It is more preferable to use an aromatic hydrocarbon having 14 to 42 carbon atoms.

[0284] The aromatic hydrocarbon may have a vinyl skeleton. Examples of aromatic hydrocarbons include 4,4'-bis(2,2-diphenylvinyl)biphenyl. (abbreviation: DPVBi), 9,10-bis[4-(2,2-diphenylvinyl)phenyl] anthracene (abbreviation: DPVPA), etc.

[0285] In addition, poly(N-vinylcarbazole) (abbreviation: PVK) and poly(4-vinyltriphenyl ether) Nylamine) (abbreviation: PVTPA), poly[N-(4-{N'-[4-(4-diphenyl amino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide]( abbreviation: PTPDMA), poly[N,N'-bis(4-butylphenyl)-N,N'-bis Polymer compounds such as [(phenyl)benzidine] (abbreviation: Poly-TPD) can also be used. can.

[0286] Furthermore, examples of materials with high hole transport properties include 4,4'-bis[N-(1-naphthyl)-2-methyl-2-propanol]. N,N'-(phenyl)-N-phenylamino]biphenyl (abbreviation: NPB or α-NPD) Bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4, 4'-diamine (abbreviation: TPD), 4,4',4''-tris(carbazol-9-yl) ) triphenylamine (abbreviation: TCTA), 4,4',4''-tris[N-(1-naphthyl) 4,4-Triphenylamine (abbreviation: 1'-TNATA) ',4''-Tris(N,N-diphenylamino)triphenylamine (abbreviation: TDAT A), 4,4',4''-tris[N-(3-methylphenyl)-N-phenylamino] Triphenylamine (abbreviation: MTDATA), 4,4'-bis[N-(spiro-9,9' -bifluoren-2-yl)-N-phenylamino]biphenyl (abbreviation: BSPB), 4 -phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenyl Nylamine (abbreviation: mBPAFLP), N-(9,9-dimethyl-9H-fluorene-2 -yl)-N-{9,9-dimethyl-2-[N'-phenyl-N'-(9,9-dimethyl -9H-fluoren-2-yl)amino]-9H-fluoren-7-yl}phenylamino N-(9,9-dimethyl-2-diphenylamino-9H- Fluoren-7-yl)diphenylamine (abbreviation: DPNF), 2-[N-(4-diphenyl) N-phenylaminophenyl)-N-phenylamino]spiro-9,9'-bifluorene (abbreviation: DPASF), 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl) Triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9- Phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1B) P), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl) Triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''- (9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviated as PCBN BB), 4-phenyldiphenyl-(9-phenyl-9H-carbazol-3-yl)a amine (abbreviation: PCA1BP), N,N'-bis(9-phenylcarbazol-3-yl) -N,N'-diphenylbenzene-1,3-diamine (abbreviation: PCA2B), N,N', N''-triphenyl-N,N',N''-tris(9-phenylcarbazole-3-yl) N-(4-biphenyl)benzene-1,3,5-triamine (abbreviation: PCA3B) -N-(9,9-dimethyl-9H-fluoren-2-yl)-9-phenyl-9H-chlor PCBiF, N-(1,1'-biphenyl-4-yl) -N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-di Methyl-9H-fluoren-2-amine (abbreviation: PCBBiF), 9,9-dimethyl-N -phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl] Fluoren-2-amine (abbreviation: PCBAF), N-phenyl-N-[4-(9-phenyl -9H-carbazol-3-yl)phenyl]spiro-9,9'-bifluorene-2-a PCBASF, 2-[N-(9-phenylcarbazol-3-yl)-N -phenylamino]spiro-9,9'-bifluorene (abbreviation: PCASF), 2,7-bi Spiro-9,9'-[N-(4-diphenylaminophenyl)-N-phenylamino]spiro Bifluorene (abbreviation: DPA2SF), N-[4-(9H-carbazol-9-yl)fluorene] N,N'-phenyl]-N-(4-phenyl)phenylaniline (abbreviation: YGA1BP), Bis[4-(carbazol-9-yl)phenyl]-N,N'-diphenyl-9,9-di Aromatic amine compounds such as methylfluorene-2,7-diamine (abbreviation: YGA2F) Also, 3-[4-(1-naphthyl)-phenyl]-9-phenyl can be used. -9H-carbazole (abbreviation: PCPN), 3-[4-(9-phenanthryl)-phenyl 3,3'-bis(9- phenyl-9H-carbazole) (abbreviation: PCCP), 1,3-bis(N-carbazolyl ) benzene (abbreviation: mCP), 3,6-bis(3,5-diphenylphenyl)-9-phenyl Nylcarbazole (abbreviation: CzTP), 3,6-di(9H-carbazol-9-yl)- 9-phenyl-9H-carbazole (abbreviation: PhCzGI), 2,8-di(9H-carbazole) 4-{3-[3-( 9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation Name: mmDBFFLBi-II), 4,4',4''-(benzene-1,3,5-triyl) 1,3,5-tri(dibenzofuran) (abbreviation: DBF3P-II), Thiophen-4-yl)benzene (abbreviation: DBT3P-II), 2,8-diphenyl-4 -[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), 4-[4-(9-phenyl-9H-fluorene-9- 4-(4-phenyl-1-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV) -[3-(triphenylen-2-yl)phenyl]dibenzothiophene (abbreviation: mDBT PTp-II) and other amine compounds, carbazole compounds, thiophene compounds, and furan compounds compounds, fluorene compounds, triphenylene compounds, phenanthrene compounds, etc. Among the above-mentioned compounds, those having a pyrrole skeleton, a furan skeleton, a thiophene skeleton, or Compounds having an aromatic amine skeleton are preferred because they are stable and reliable. Compounds having such a property have high hole transporting properties and also contribute to reducing the driving voltage.

[0287] The light-emitting layer 130 and the light-emitting layer 135 may be composed of two or more layers. For example, the first light-emitting layer and the second light-emitting layer may be laminated in this order from the hole transport layer side to form the light-emitting layer 13. 0 or the light-emitting layer 135, a material having hole transport properties as a host material of the first light-emitting layer a structure in which a substance having an electron transport property is used as a host material for the second light-emitting layer; Furthermore, the light-emitting materials contained in the first light-emitting layer and the second light-emitting layer may be the same material. The materials may be different, and even if they have the function of emitting light of the same color, The two light-emitting layers may be made of a material having a function of emitting light of different colors. By using luminescent materials each having the function of emitting light, multiple lights can be obtained simultaneously. In particular, the two light-emitting layers can be used to produce white light. It is preferable to select a light-emitting material that has a high luminescence intensity.

[0288] In addition, in the light-emitting layer 130, materials other than the host material 132 and the guest material 131 are In the light-emitting layer 135, the host material 133 and the host material 132 may be , and may contain materials other than the guest material 131.

[0289] The light-emitting layers 130 and 135 can be formed by a deposition method (including a vacuum deposition method), an ink-jet method, or the like. The material can be formed by a method such as a printing method, a coating method, or a gravure printing method. , quantum dots, and other inorganic compounds or polymer compounds (oligomers, dendrimers, polymers) - etc.).

[0290] Quantum dots include colloidal quantum dots, alloy quantum dots, and core-shell quantum dots. It is also possible to use quantum dots of the 2nd group and the 16th group, quantum dots of the 13th group, and the like. Contains element groups from group 15, 13 and 17, 11 and 17, or 14 and 15 Quantum dots may also be used. Alternatively, cadmium (Cd), selenium (Se), zinc (Zn ), sulfur (S), phosphorus (P), indium (In), tellurium (Te), lead (Pb), gallium Quantum dots containing elements such as Ga, As, and Al are used. It's fine.

[0291] <Hole injection layer> The hole injection layer 111 is formed by injecting holes from one of the pair of electrodes (electrode 101 or electrode 102). It has the function of promoting hole injection by reducing the injection barrier, and is used in materials such as transition metal oxides and fluorine. It is formed by phthalocyanine derivatives or aromatic amines. Examples include molybdenum oxide, vanadium oxide, ruthenium oxide, and tungsten oxide. , manganese oxide, etc. Phthalocyanine derivatives include phthalocyanine, Examples of aromatic amines include benzidine derivatives and phenyl Diamine derivatives, etc. Polymer compounds such as polythiophene and polyaniline Materials such as self-doped polythiophenes, poly(ethylenediamines), can also be used. Typical examples include poly(oxythiophene) / poly(styrenesulfonic acid).

[0292] The hole injection layer 111 is made of a compound material including a hole transporting material and a material that exhibits electron accepting properties. Alternatively, a layer containing a material exhibiting electron accepting properties and a layer containing a material exhibiting electron accepting properties may be used. A stack of layers containing hole transport materials may also be used. It is possible to exchange charges in the presence of a magnetic field. Materials that exhibit electron-accepting properties include quinodimethane. Organic acceptors such as benzophenone derivatives, chloranil derivatives, and hexaazatriphenylene derivatives Specifically, 7,7,8,8-tetracyano-2,3,5,6- Tetrafluoroquinodimethane (abbreviation: F4-TCNQ), chloranil, 2,3,6,7, 10,11-Hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation These compounds have electron-withdrawing groups (halogen groups or cyano groups), such as hydroxybenzoates (HAT-CN). In addition, transition metal oxides, for example, oxides of metals from Groups 4 to 8, can be used. In general, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, These include tungsten oxide, manganese oxide, and rhenium oxide. Among these, it is preferred because it is stable, has low hygroscopicity, and is easy to handle.

[0293] As the hole transporting material, a material having a higher hole transporting property than an electron transporting property can be used. x10 -6 cm 2 It is preferable that the material has a hole mobility of 1 / Vs or more. The aromatic amines and carbazoles listed as hole transport materials that can be used in the light-emitting layer are The hole transporting agent may be a fluorine derivative, an aromatic hydrocarbon, a stilbene derivative, or the like. The transport material may be a polymer compound.

[0294] <Hole transport layer> The hole transport layer 112 is a layer containing a hole transport material. The hole transporting layer 112 can be formed by the hole injection layer 111. The highest occupied molecular orbital of the hole injection layer 111 is used to transport the injected holes to the light emitting layer. (Highest Occupied Molecular Orbital, HOMO It is preferable that the HOMO level is the same as or close to the HOMO level (also called the HOMO level).

[0295] Also, 1×10 -6 cm 2 It is preferable that the material has a hole mobility of 1 / Vs or more. However, other substances may be used as long as they have a higher hole transporting property than electron transporting property. The layer containing a substance with a high hole transporting property may be a single layer or a double layer of the above substance. More than one layer may be stacked.

[0296] ≪Electron transport layer≫ The electron transport layer 118 is connected to the other of the pair of electrodes (electrode 101 or electrode 102) via the electron injection layer 119. It has the function of transporting electrons injected from the electrode 102) to the light-emitting layer. can use materials with higher electron transport properties than holes, and -6 cm 2 / Vs It is preferable that the material has an electron mobility of at least 1000 keV. As materials with electron transport properties, π-electron deficient heteroaromatic compounds such as nitrogen-containing heteroaromatic compounds are Aromatic compounds and metal complexes can be used. Quinoline, benzoquinoline, and oxazole ligands listed as electron transport materials or metal complexes having thiazole ligands, oxadiazole derivatives, triazoles Derivatives, benzimidazole derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives , phenanthroline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, riazine derivatives. Also, 1×10 -6 cm 2 / Vs or higher electron mobility It is preferable that the material has a higher electron transporting property than a hole transporting property. The electron transport layer 118 may be made of a material other than the above. In addition, two or more layers made of the above materials may be laminated.

[0297] Furthermore, a layer for controlling the movement of electron carriers may be provided between the electron transport layer 118 and the light emitting layer. The layer that controls the movement of electron carriers is made of a material with high electron transport properties as described above, and This layer contains a small amount of a substance with high trapping properties, and it suppresses the movement of electron carriers. This makes it possible to adjust the carrier balance. This is effective in preventing problems caused by electrons penetrating through the device (such as a reduction in device life). It is effective.

[0298] ≪Electron injection layer≫ The electron injection layer 119 promotes electron injection by reducing the electron injection barrier from the electrode 102. For example, Group 1 metals, Group 2 metals, or their oxides and halides In addition, the electron transport material and the corresponding electron transport material can be used. A composite material of a material exhibiting electron donating properties can also be used. Examples include Group 1 metals, Group 2 metals, and oxides thereof. are lithium fluoride (LiF), sodium fluoride (NaF), and cesium fluoride (CsF ), calcium fluoride (CaF2), lithium oxide (LiO x ) and other alkaline gold Metals, alkaline earth metals, or compounds thereof can be used. A rare earth metal compound such as erbium (ErF3) can be used. An electride may be used for 119. The electride may be, for example, calcium. Examples include a material in which electrons are highly concentrated in a mixed oxide of aluminum and silicon. The injection layer 119 may be made of a material that can be used in the electron transport layer 118 .

[0299] The electron injection layer 119 may contain a composite material formed by mixing an organic compound and an electron donor (donor). Such composite materials may be formed by electron donors giving electrons to organic compounds. In this case, the organic compound is It is preferable that the material is excellent in transporting the generated electrons. Specifically, for example, the above-mentioned The material constituting the electron transport layer 118 (metal complex, heteroaromatic compound, etc.) can be used. The electron donor may be any substance that exhibits electron donating properties to organic compounds. For the metal, alkali metals, alkaline earth metals and rare earth metals are preferred, and lithium, sodium , cesium, magnesium, calcium, erbium, ytterbium, etc. In addition, alkali metal oxides and alkaline earth metal oxides are preferred, and lithium oxide, calcium oxide, Examples of oxides include sodium oxide and barium oxide. Lewis oxides such as magnesium oxide are also included. A base can also be used. In addition, organic compounds such as tetrathiafulvalene (TTF) can be used. You can also use objects.

[0300] The above-mentioned light-emitting layer, hole-injection layer, hole-transport layer, electron-transport layer, and electron-injection layer are These methods include vapor deposition (including vacuum deposition), inkjet printing, coating, and gravure printing. The light-emitting layer, the hole-injecting layer, the hole-transporting layer, the electron In addition to the materials mentioned above, inorganic compounds such as quantum dots and high molecular weight compounds can be used for the transport layer and electron injection layer. A polymer compound (oligomer, dendrimer, polymer, etc.) may also be used.

[0301] <Pair of electrodes> The electrode 101 and the electrode 102 function as an anode or a cathode of the light-emitting element. The electrode 101 and the electrode 102 may be made of a metal, an alloy, a conductive compound, or a mixture or laminate thereof. It can be formed using, for example.

[0302] One of the electrodes 101 and 102 is made of a conductive material that has a function of reflecting light. The conductive material is preferably aluminum (Al) or a compound containing Al. Examples of alloys containing Al include Al and L (L is titanium (Ti), neodymium (Ne), etc. (representing one or more of Nd, Ni, and La) Examples of suitable alloys include alloys containing Al and Ti, or alloys containing Al, Ni and La. Aluminum has low resistance and high light reflectivity. Since aluminum is abundant and inexpensive, the cost of manufacturing a light-emitting element using aluminum is reduced. In addition, silver (Ag) or Ag and N (N) can be used in combination with yttrium ( Y), Nd, magnesium (Mg), ytterbium (Yb), Al, Ti, gallium ( Ga), zinc (Zn), indium (In), tungsten (W), manganese (Mn), Tin (Sn), iron (Fe), Ni, copper (Cu), palladium (Pd), iridium (Ir ), or an alloy containing gold (Au), etc. Examples of alloys containing silver include alloys containing silver, palladium, and copper, alloys containing silver and copper, and alloys containing silver and magnesium. Alloys containing nesium, alloys containing silver and nickel, alloys containing silver and gold, silver and ytterbium Other examples include alloys containing tungsten, chromium (Cr), molybdenum (Mo ), copper, titanium, and other transition metals can be used.

[0303] The light emitted from the light-emitting layer is emitted through one or both of the electrodes 101 and 102. Therefore, at least one of the electrodes 101 and 102 is transparent to light. It is preferable that the conductive material is made of a conductive material having a function of transmitting visible light. The light transmittance is 40% or more and 100% or less, preferably 60% or more and 100% or less, and Its resistivity is 1×10 -2 Examples include conductive materials with a resistance of Ω·cm or less.

[0304] The electrodes 101 and 102 have a function of transmitting light and a function of reflecting light. The conductive material may be formed of a conductive material having a visible light reflectance of 20 or less. % or more and 80% or less, preferably 40% or more and 70% or less, and the resistivity is 1×10 -2 Conductive materials with a resistance of Ω·cm or less include metals, alloys, and conductive materials. The layer can be formed by using one or more of the following compounds. Indium Tin Oxide (ITO), silicon or silicon oxide Indium tin oxide (ITSO), indium oxide-zinc oxide (Indi Indium tin oxide containing titanium, indium tin oxide, Metals such as indium oxide containing titanium oxide, tungsten oxide, and zinc oxide Oxides can be used. In addition, the thickness of the oxide is preferably within a range of 1 nm to 30 nm. A metal thin film having a thickness of 1 μm or less can be used. Examples of metals include Ag, Alloys such as Ag and Al, Ag and Mg, Ag and Au, and Ag and Yb can be used.

[0305] In this specification and the like, a material having a function of transmitting light refers to a material having a function of transmitting visible light. Any material having the above and having electrical conductivity may be used, and examples thereof include ITO. In addition to oxide conductors, oxide semiconductors or organic conductors containing organic materials are also included. The organic conductor may be, for example, a mixture of an organic compound and an electron donor. Examples of such materials include composite materials, and composite materials made by mixing organic compounds and electron acceptors. Alternatively, inorganic carbon materials such as graphene may be used. The ratio is preferably 1 x 10 5 Ω·cm or less, more preferably 1×10 4 Ω cm The following is the result.

[0306] In addition, by laminating a plurality of the above materials, one or both of the electrodes 101 and 102 can be formed. may form both.

[0307] In order to improve the light extraction efficiency, the electrode is in contact with the light-transmitting electrode. A material having a higher refractive index than the electrode may be used. Any material that has the function of providing the desired electrical conductivity may be used. For example, in addition to the oxide conductors described above, oxide semiconductors and organic materials can be used. The organic material may be, for example, a light-emitting layer, a hole injection layer, a hole transport layer, an electron transport layer, or an electron transport layer. The materials exemplified for the electron injection layer are also usable. Inorganic carbon materials and thin films that are light-transmitting are also usable. These high refractive index materials can be used to form thin films with a size of several nanometers to several tens of nanometers. A plurality of layers may be laminated.

[0308] When the electrode 101 or the electrode 102 functions as a cathode, the work function is small. (3.8 eV or less) materials. For example, materials in Group 1 or 2 of the Periodic Table of Elements. Elements belonging to the group (alkali metals such as lithium, sodium, and cesium, calcium, strontium, etc.) Alkaline earth metals such as rontium, magnesium, etc.), alloys containing these elements (e.g., Rare earth metals such as Ag and Mg, Al and Li), europium (Eu), Yb, etc. An alloy containing a metal, such as an alloy containing aluminum or silver, can be used.

[0309] Furthermore, when the electrode 101 or the electrode 102 is used as an anode, a material having a large work function (4. It is preferable to use a material having a refractive index of 0 eV or more.

[0310] The electrodes 101 and 102 are made of a conductive material that reflects light and a light-transmitting material. In this case, the electrode 101 and the electrode 102 may be laminated with a conductive material having a permeability function. 02 can resonate light of a desired wavelength from each light-emitting layer and intensify the light of that wavelength. This is preferable because it allows for the function of adjusting the optical distance.

[0311] The electrode 101 and the electrode 102 can be formed by a sputtering method, a vapor deposition method, a printing method, or a coating method. , MBE (Molecular Beam Epitaxy) method, CVD method, pulse laser The deposition method, ALD (Atomic Layer Deposition) method, etc. are used appropriately. It is possible.

[0312] <Substrate> Furthermore, the light-emitting element according to one embodiment of the present invention may be formed on a substrate made of glass, plastic, or the like. As for the order of fabrication on the substrate, the layers may be stacked in order from the electrode 101 side. They may be stacked in order from the pole 102 side.

[0313] The substrate on which the light-emitting element according to one embodiment of the present invention can be formed is, for example, glass or quartz. Alternatively, a flexible substrate may be used. The substrate is a flexible substrate, such as polycarbonate. Examples of suitable substrates include plastic substrates made of vinyl acetate and polyarylate. Inorganic vapor deposition films can also be used. Any other material may be used as long as it functions as a support in the development. Anything that has the function of protecting the optical element and the optical device may be used.

[0314] For example, in the present invention, a light emitting element can be formed using various substrates. The type of substrate is not particularly limited. An example of the substrate is a semiconductor substrate (e.g., (e.g., single crystal substrate or silicon substrate), SOI substrate, glass substrate, quartz substrate, plastic substrate Plate, metal substrate, stainless steel substrate, substrate with stainless steel foil, Tungsten substrate, substrate with tungsten foil, flexible substrate, laminated film Examples of glass substrates include paper containing fibrous materials and base films. Examples include sodium borosilicate glass, aluminoborosilicate glass, and soda-lime glass. Examples of flexible substrates, laminated films, base films, etc. include the following: For example, polyethylene terephthalate (PET), polyethylene naphthalate (P EN), polyethersulfone (PES), polytetrafluoroethylene (PTFE) A typical example is plastic. Another example is resin such as acrylic. Alternatively, for example, polypropylene, polyester, polyvinyl fluoride, or polychloride Examples include polyamide, polyimide, aramid, and epoxy. Examples include glass, inorganic vapor deposition film, and paper.

[0315] Alternatively, a flexible substrate may be used as the substrate, and the light emitting element may be formed directly on the flexible substrate. Alternatively, a release layer may be provided between the substrate and the light-emitting element. After a part or all of a device is completed, it is separated from the substrate and used to transfer it to another substrate. In this case, the light-emitting element can be transferred onto a substrate having poor heat resistance or a flexible substrate. The peeling layer may have a laminated structure of inorganic films, such as a tungsten film and a silicon oxide film. or a structure in which a resin film such as polyimide is formed on a substrate, etc., can be used.

[0316] That is, a light emitting element is formed using a certain substrate, and then the light emitting element is transferred to another substrate. The light emitting element may be disposed on another substrate. In addition to the substrates mentioned above, cellophane substrates, stone substrates, wood substrates, fabric substrates (natural fibers (silk, cotton, Hemp), synthetic fibers (nylon, polyurethane, polyester) or regenerated fibers (acetate (including cellulose, cupro, rayon, recycled polyester, etc.), leather substrate, rubber substrate, etc. By using these substrates, it is possible to produce light emitting elements that are durable and highly heat resistant. The light emitting element may be a small, lightweight, or thin light emitting element.

[0317] Furthermore, for example, a field effect transistor (FET) is formed on the above-mentioned substrate, and the FET and The light emitting element 150 may be fabricated on the electrically connected electrodes. In this way, an active matrix display device that controls the driving of the light emitting element 150 can be fabricated.

[0318] Note that one embodiment of the present invention has been described in this embodiment. However, the present invention is not limited to these embodiments. That is, various inventive aspects are described in this and other embodiments. Therefore, one embodiment of the present invention is not limited to a specific embodiment. However, one embodiment of the present invention is not limited to this. For example, in some cases or depending on the situation, one embodiment of the present invention may be applied to a light-emitting element. Alternatively, for example, in one embodiment of the present invention, a compound that emits triplet excitation energy may not be used. and at least one host material. The LUMO level of the guest material is higher than that of the host material, and the H Although an example in which the OMO level is lower than the HOMO level of the host material has been shown, this is one embodiment of the present invention. However, in some cases or depending on the situation, in one aspect of the present invention, For example, the LUMO level of the guest material does not have to be higher than the LUMO level of the host material. Alternatively, the HOMO level of the guest material is not lower than that of the host material. Alternatively, for example, in one embodiment of the present invention, the host material may have a singlet excited energy level Example of when the difference between the energy level and the triplet excited energy level is greater than 0 eV and less than 0.2 eV However, one aspect of the present invention is not limited to this. Accordingly, in one aspect of the present invention, for example, the host material has a singlet excited energy level and a triplet excited energy level. The difference between the first and second excitation energy levels may be greater than 0.2 eV.

[0319] As described above, the structure shown in this embodiment mode can be used in appropriate combination with other embodiment modes. Cut.

[0320] (Embodiment 2) In this embodiment mode, a light-emitting element having a different structure from that of the light-emitting element shown in Embodiment 1 is This will be explained below with reference to FIG. 5. In FIG. 5(A), The same hatch pattern is used for parts with the same function as the symbol, and the symbol may be omitted. In addition, parts having similar functions are denoted by similar reference numerals, and detailed descriptions thereof are omitted. This may occur.

[0321] <Configuration example of light-emitting element> FIG. 5A is a schematic cross-sectional view of the light emitting element 250. FIG.

[0322] The light-emitting element 250 shown in FIG. 5A has a pair of electrodes (electrodes 101 and 102) between them. , a plurality of light-emitting units (in FIG. 5A, light-emitting unit 106 and light-emitting unit 1 08). Any one of the plurality of light-emitting units has the light-emitting unit shown in FIG. It is preferable that the EL layer 100 has a structure similar to that of the EL layer 100 shown in FIG. The element 150 and the light-emitting element 152 shown in FIG. 3 have one light-emitting unit, and the light-emitting element 25 It is preferable that the light emitting element 250 has a plurality of light emitting units. The following description will be given assuming that electrode 101 functions as an anode and electrode 102 functions as a cathode. The configuration of the optical element 250 may be reversed.

[0323] In addition, in the light-emitting element 250 shown in FIG. 5(A), the light-emitting unit 106 and the light-emitting unit The light-emitting units 106 and 108 are stacked, and a charge generating layer is formed between the light-emitting units 106 and 108. The light-emitting unit 106 and the light-emitting unit 108 have the same structure. For example, the light-emitting unit 108 may have an EL layer shown in FIG. It is preferable to use 100.

[0324] The light emitting element 250 has a light emitting layer 120 and a light emitting layer 170. In addition to the light-emitting layer 120, the knit 106 includes a hole injection layer 111, a hole transport layer 112, an electron transport layer The light-emitting unit 108 also includes an emissive layer 170. In addition to the above, a hole injection layer 116, a hole transport layer 117, an electron transport layer 118, and an electron injection layer 11 It has 9.

[0325] The charge generation layer 115 is formed by adding an acceptor material, which is an electron acceptor, to a hole transport material. Even if the electron transport material is an electron donor, a donor material may be added to the electron transport material. Alternatively, both of these structures may be stacked.

[0326] When the charge generation layer 115 contains a composite material of an organic compound and an acceptor substance, the The composite material that can be used for the hole-injection layer 111 shown in Embodiment 1 is used as the composite material. The organic compounds include aromatic amine compounds, carbazole compounds, aromatic carbonized compounds, and the like. Various compounds such as hydrogen and polymer compounds (oligomers, dendrimers, polymers, etc.) are used. As for organic compounds, those with a hole mobility of 1×10 -6 cm 2 / Vs However, it is preferable to use a substance having a higher hole transporting property than an electron transporting property. Other materials may be used as long as they are compatible with the organic compound and the acceptor material. The material has excellent carrier injection and carrier transport properties, allowing for low voltage and low current operation. In addition, as in the light-emitting unit 108, the surface of the light-emitting unit on the anode side When the charge generating layer 115 is in contact with the charge generating layer 115, the charge generating layer 115 is the hole injection layer of the light emitting unit. Since the light-emitting unit can also function as a hole-injection layer or a hole-transport layer, The hole transport layer may not be provided.

[0327] The charge generation layer 115 may be a layer containing a composite material of an organic compound and an acceptor substance, or another layer containing a compound of an organic compound and an acceptor substance. For example, the organic EL element may be formed as a laminated structure in which layers made of the organic EL element are combined. A layer including a composite material of a compound and an acceptor substance and a layer including a compound selected from electron donor substances. The compound may be formed by combining a layer containing the compound with a compound having a high electron transporting property. A layer containing a composite material of an organic compound and an acceptor substance and a layer containing a transparent conductive film are combined. It may be formed by combining the above.

[0328] The charge generating layer 115 sandwiched between the light emitting unit 106 and the light emitting unit 108 When a voltage is applied between the electrode 101 and the electrode 102, electrons are injected into one of the light-emitting units, It is sufficient if the hole is injected into the other light-emitting unit. For example, in FIG. 5(A), When a voltage is applied so that the potential of electrode 101 is higher than the potential of electrode 102, The charge generating layer 115 injects electrons into the light-emitting unit 106 and holes into the light-emitting unit 108. Enter.

[0329] From the viewpoint of light extraction efficiency, the charge generation layer 115 is transparent to visible light (specifically, It is preferable that the charge generating layer 115 has a visible light transmittance of 40% or more. The charge generating layer 115 has a lower conductivity than the pair of electrodes (electrodes 101 and 102). It still works.

[0330] By forming the charge generating layer 115 using the above-mentioned materials, when a light emitting layer is laminated, In this case, the increase in the driving voltage can be suppressed.

[0331] In addition, in FIG. 5A, a light-emitting element having two light-emitting units has been described. However, it can also be applied to light-emitting devices in which three or more light-emitting units are stacked. As shown in the light-emitting element 250, a plurality of light-emitting units are disposed between a pair of electrodes, and a charge generating layer is formed. By separating the layers, high brightness light emission is possible while keeping the current density low. A light-emitting element with a long life and low power consumption can be realized. .

[0332] At least one of the multiple units has the structure shown in the first embodiment. By applying this composition, a light-emitting element with high luminous efficiency can be provided.

[0333] The light-emitting layer 170 of the light-emitting unit 108 is the same as the light-emitting layer 13 shown in Embodiment 1. It is preferable that the light-emitting layer 170 has the same structure as the light-emitting layer 135 in the first embodiment. By having a structure similar to that of the light-emitting layer 130 or the light-emitting layer 135 shown in FIG. This is preferable as a light emitting element with high luminous efficiency.

[0334] Furthermore, the light-emitting layer 120 of the light-emitting unit 106 is formed by adding a guest The guest material 121 is a fluorescent material. , as explained below.

[0335] <Light Emitting Mechanism of Light Emitting Layer 120> The light emitting mechanism of the light emitting layer 120 will be explained below.

[0336] Electrons injected from a pair of electrodes (electrodes 101 and 102) or a charge generating layer and The recombination of the guest material 1 and the electron hole in the light-emitting layer 120 generates an exciton. Since the host material 122 is present in a large amount compared to 21, the generation of excitons An excited state of the material 122 is formed.

[0337] An exciton is a pair of carriers (electrons and holes). Therefore, the material in which the excitons are generated is in an excited state.

[0338] When the excited state of the formed host material 122 is a singlet excited state, the host material 12 Singlet excitation energy is transferred from the S1 level of 2 to the S1 level of the guest material 121. As a result, the singlet excited state of the guest material 121 is formed.

[0339] Since the guest material 121 is a fluorescent material, the singlet excited state in the guest material 121 is Once formed, the guest material 121 quickly emits light. For this purpose, it is preferable that the guest material 121 has a high fluorescence quantum yield. In 1, the same applies when carriers recombine and the resulting excited state is a singlet excited state. is.

[0340] Next, when carrier recombination forms a triplet excited state of the host material 122, In this case, the energy levels of the host material 122 and the guest material 121 are The correlation between the positions is shown in Figure 5(C). The notations and symbols in Figure 5(C) are as follows: The T1 level of the host material 122 is lower than the T1 level of the guest material 121. Since this is preferable, this case is illustrated in FIG. 5C. may be higher than the T1 level of the guest material 121.

[0341] Guest (121): Guest material 121 (fluorescent material) Host (122): Host material 122 ·S FG : S1 level of guest material 121 (fluorescent material) T FG : T1 level of guest material 121 (fluorescent material) ·S FH : S1 level of the host material 122 T FH : T1 level of the host material 122

[0342] As shown in Figure 5(C), triplet-triplet annihilation (TTA) Triplets generated by carrier recombination (by Excitons interact with each other, transferring excitation energy and exchanging spin angular momentum. As a result, the S1 level (S FH ) with energy A reaction occurs in which the host material 122 is converted into a doublet exciton (see TTA in FIG. 5(C)). The singlet excitation energy is S FH From the lower energy guest material 121 S1 level (S FG ) (see route E3 in Figure 5(C)), and the guest material A singlet excited state of the guest material 121 is formed, and the guest material 121 emits light.

[0343] When the density of triplet excitons in the light-emitting layer 120 is sufficiently high (for example, 1×10 -12 cm -3 In the above, the deactivation of a single triplet exciton is ignored, and the deactivation of two adjacent triplet excitons is considered. Only reactions due to triggers can be considered.

[0344] In addition, when carriers recombine in the guest material 121 to form a triplet excited state, However, the triplet excited state of the guest material 121 is thermally deactivated, making it difficult to utilize it for light emission. However, the T1 level (T FH ) is the T1 equivalent of guest material 121 Place(T FG ), the triplet excitation energy of guest material 121 is lower than that of guest material 1 21 T1 levels (T FG ) to the T1 level (T FH ) Energy transfer (See route E4 in Figure 5(C)) and then used for TTA.

[0345] That is, the host material 122 converts triplet excitation energy into singlet excitation energy by TTA. It is preferable that the light-emitting layer 120 has a function of converting the generated light into energy. A portion of the triplet excitation energy is converted to singlet excitation energy by TTA in the host material 122. The singlet excitation energy is converted into the guest material 121, and the guest material 121 is transferred to the guest material 121, thereby producing fluorescence. To achieve this, the S1 level (S FH ) is the S1 level (S FG ) is preferable. The T1 level (T FH ) is the T1 level (T FG ) lower It is preferable.

[0346] In particular, the T1 level (T FG ) is the T1 level of the host material 122 ( T FH ), the weight ratio of the host material 122 to the guest material 121 is It is preferable that the weight ratio of the guest material 121 is low. The weight ratio of the guest material 121 to the total is preferably greater than 0 and equal to or less than 0.05. By adjusting the weight ratio, the probability of carrier recombination in the guest material 121 is reduced. In addition, the T1 level (T FH ) from guest material 121 T 1 level (T FG ) can reduce the probability of energy transfer to

[0347] The host material 122 may be composed of a single compound or a plurality of compounds. It may be formed.

[0348] In each of the above configurations, the gates used in the light-emitting units 106 and 108 The light-emitting materials may emit the same or different colors. In the case where the light-emitting unit 106 and the light-emitting unit 108 have guest materials that have the function of emitting light of the same color, In this case, the light emitting element 250 is preferable as it exhibits high light emitting brightness with a small current value. In addition, the light-emitting units 106 and 108 have the function of emitting light of different colors. When the light-emitting element 250 contains a guest material having the above-mentioned structure, the light-emitting element 250 becomes a light-emitting element that exhibits multicolor emission, which is preferable. In this case, it is preferable to provide a light emitting layer 120 or a light emitting layer 170 having an emission wavelength of 1000 nm or more. By using different light-emitting materials, the light-emitting element 250 exhibits an emission spectrum of Since the light emitted from the source has different emission peaks, it has at least two maxima. The resulting emission spectrum is

[0349] The above-mentioned configuration is also suitable for obtaining white light emission. By making the colors complementary to each other, white light can be emitted. The guest is then reacted with the guest to produce a highly white luminescent compound, or at least a luminescent compound having red, green, and blue components. The choice of material is preferred.

[0350] In addition, either or both of the light-emitting layer 120 and the light-emitting layer 170 may be further divided into layers. Each of the divided layers may contain a different light-emitting material. Either or both of the layer 120 and the light-emitting layer 170 are composed of two or more layers. For example, the first light-emitting layer and the second light-emitting layer may be stacked in this order from the hole transport layer side. When the light-emitting layer is formed by using a material having a hole-transporting property as a host material of the first light-emitting layer, For example, a substance having an electron transporting property is used as a host material for the second light-emitting layer. In this case, the light-emitting materials of the first light-emitting layer and the second light-emitting layer may be different materials even if they are the same material. Even if the material has the function of emitting light of the same color, it may emit light of different colors. The materials may be materials that have the function of emitting light of different colors. The structure of the LEDs is made up of multiple light-emitting materials, and they emit three primary colors or four or more colors with high color rendering. White light emission can also be obtained.

[0351] In addition, the light-emitting units 106 and 108 have guest materials with different emission colors. In this case, the emission from the light-emitting layer 120 has a peak in the shorter wavelength side than the emission from the light-emitting layer 170. It is preferable to use a material having a high triplet excitation energy level. The light-emitting element used in this method tends to have a tendency to deteriorate quickly in brightness. By using TA, it is possible to provide a light-emitting element with little deterioration in luminance.

[0352] <Examples of materials that can be used for the light-emitting layer> Next, materials that can be used for the light-emitting layer 120 and the light-emitting layer 170 will be described below. do.

[0353] <Materials that can be used for the light-emitting layer 120> In the light-emitting layer 120, the host material 122 is present in the largest amount by weight, and the guest material 121 The fluorescent material is dispersed in the host material 122. The S1 level of the host material 122 is The S1 level of the host material 122 is higher than the S1 level of the fluorescent material 121. It is preferable that the T1 level is lower than the T1 level of the source material 121 (fluorescent material).

[0354] In the light-emitting layer 120, the guest material 121 is not particularly limited, but may be anthracene. derivatives, tetracene derivatives, chrysene derivatives, phenanthrene derivatives, pyrene derivatives, Rylene derivatives, stilbene derivatives, acridone derivatives, coumarin derivatives, phenoxazine Derivatives, phenothiazine derivatives, etc. are preferred, and for example, the following materials can be used: .

[0355] Specifically, 5,6-bis[4-(10-phenyl-9-anthryl)phenyl]-2 ,2'-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl -9-anthryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2 BPy), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoro (9-phenyl)pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn) , N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H -fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMem FLPAPrn), N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl )phenyl]-N,N'-bis(4-tert-butylphenyl)pyrene-1,6-diazo amine (abbreviation: 1,6tBu-FLPAPrn), N,N'-diphenyl-N,N'-bis [4-(9-phenyl-9H-fluoren-9-yl)phenyl]-3,8-dicyclohexyl Xylpyrene-1,6-diamine (abbreviation: ch-1,6FLPAPrn), N,N'-biphenyl bis[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenylstilbe 4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazol-9-yl) -4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA) , 4-(9H-carbazol-9-yl)-4'-(9,10-diphenyl-2-anthracene) N,9-diphenyl-N-[4- (10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation Name: PCAPA), Perylene, 2,5,8,11-tetra(tert-butyl)perylene (abbreviation: TBP), 4-(10-phenyl-9-anthryl)-4'-(9-phenyl- 9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAPA), N,N' '-(2-tert-butylanthracene-9,10-diyldi-4,1-phenylene) Bis[N,N',N'-triphenyl-1,4-phenylenediamine] (abbreviation: DPAB PA), N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl] phenyl]-9H-carbazol-3-amine (abbreviation: 2PCAPPA), N-[4-(9 ,10-diphenyl-2-anthryl)phenyl]-N,N',N'-triphenyl-1 ,4-Phenylenediamine (abbreviation: 2DPAPPA), N,N,N',N',N'',N '',N''',N'''-Octaphenyldibenzo[g,p]chrysene-2,7,10 ,15-tetraamine (abbreviation: DBC1), Coumarin 30, N-(9,10-diphenyl -2-anthryl)-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2 PCAPA), N-[9,10-bis(1,1'-biphenyl-2-yl)-2-anthracene] aryl]-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCABPh A), N-(9,10-diphenyl-2-anthryl)-N,N',N'-triphenyl -1,4-phenylenediamine (abbreviation: 2DPAPA), N-[9,10-bis(1,1 '-biphenyl-2-yl)-2-anthryl]-N,N',N'-triphenyl-1, 4-Phenylenediamine (abbreviation: 2DPABPhA), 9,10-bis(1,1'-biphenyl) (9H-carbazol-9-yl)phenyl)-N-[4-(9H-carbazol-9-yl)phenyl]-N- Phenylanthracene-2-amine (abbreviation: 2YGABPhA), N,N,9-triphenyl Dianthracen-9-amine (abbreviation: DPhAPhA), Coumarin 6, Coumarin 545T , N,N'-diphenylquinacridone (abbreviation: DPQd), rubrene, 2,8-di-te rt-Butyl-5,11-bis(4-tert-butylphenyl)-6,12-diphenyl Tetrathracene (abbreviation: TBRb), Nile Red, 5,12-bis(1,1'-biphenyl) 2-(2-(2-phenyl-4-yl)-6,11-diphenyltetracene (abbreviation: BPT), [4-(dimethylamino)phenyl]ethenyl}-6-methyl-4H-pyran-4-yl 2-(2-methyl-6-[(2,3-dimethyl- ... ,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl ]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCM2), N,N,N ',N'-Tetrakis(4-methylphenyl)tetracene-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-N,N,N',N'-tetrakis(4-methyl phenyl)acenaphtho[1,2-a]fluoranthene-3,10-diamine (abbreviation: p -mPhAFD), 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl 2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl )ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTI) , 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3, 6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl] -4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTB), 2-(2, 6-Bis{2-[4-(dimethylamino)phenyl]ethenyl}-4H-pyran-4-yl 2-(2,6-bis[2-(8- Methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H -benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}p Dopanedinitrile (abbreviation: BisDCJTM), 5,10,15,20-tetraphenyl Bisbenzo[5,6]indeno[1,2,3-cd:1',2',3'-lm]perylene , etc.

[0356] In addition, materials that can be used as the host material 122 in the light-emitting layer 120 include: Although there is no particular limitation, for example, tris(8-quinolinolato)aluminum(III) (abbreviation : Alq), tris(4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Almq3), bis(10-hydroxybenzo[h]quinolinato)beryllium(II)( Abbreviation: BeBq2), bis(2-methyl-8-quinolinolato)(4-phenylphenolato) ) Aluminum(III) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Znq), bis[2-(2-benzoxazolyl)phenolato]zinc(II)( Abbreviation: ZnPBO), bis[2-(2-benzothiazolyl)phenolato]zinc(II) ( abbreviation: ZnBTZ), metal complexes such as 2-(4-biphenylyl)-5-(4-tert- butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5 -(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene OXD-7, 3-(4-biphenylyl)-4-phenyl-5-(4-te rt-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 2,2',2' '-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazoline) TPBI), bathophenanthroline (BPhen), bathocuproline BCP, 9-[4-(5-phenyl-1,3,4-oxadiazole-2- Heterocyclic compounds such as 4,4-phenyl-9H-carbazole (abbreviation: CO11), '-Bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviated as NPB) is α-NPD), N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1 ,1'-biphenyl]-4,4'-diamine (abbreviation: TPD), 4,4'-bis[N-( spiro-9,9'-bifluoren-2-yl)-N-phenylamino]biphenyl (abbreviation Aromatic amine compounds such as benzophenone (BSPB) are also suitable. Nanthrene derivatives, pyrene derivatives, chrysene derivatives, dibenzo[g,p]chrysene derivatives Condensed polycyclic aromatic compounds such as 9,10-diphenylanthracene are specifically exemplified. (abbreviation: DPAnth), N,N-diphenyl-9-[4-(10-phenyl-9-anthracene] tolyl)phenyl]-9H-carbazol-3-amine (abbreviation: CzA1PA), 4-( 10-phenyl-9-anthryl)triphenylamine (abbreviation: DPhPA), 4-(9 H-carbazol-9-yl)-4'-(10-phenyl-9-anthryl)tripheny YGAPA, N,9-diphenyl-N-[4-(10-phenyl-9 -anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: PCAPA), N ,9-diphenyl-N-{4-[4-(10-phenyl-9-anthryl)phenyl]phenyl {phenyl}-9H-carbazol-3-amine (abbreviation: PCAPBA), N,9-diphenyl N-(9,10-diphenyl-2-anthryl)-9H-carbazol-3-amine (abbreviation: 2PCAPA), 6,12-dimethoxy-5,11-diphenylchrysene, N, N,N',N',N'',N'',N''',N'''-octaphenyldibenzo[g, p]chrysene-2,7,10,15-tetraamine (abbreviation: DBC1), 9-[4-(1 0-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: CzPA), 3,6-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H -carbazole (abbreviation: DPCzPA), 9,10-bis(3,5-diphenylphenyl) ) anthracene (abbreviation: DPPA), 9,10-di(2-naphthyl)anthracene (abbreviation: :DNA), 2-tert-butyl-9,10-di(2-naphthyl)anthracene (abbreviation :t-BuDNA), 9,9'-bianthryl (abbreviation: BANT), 9,9'-(styryl) 9,9'-(stilbene-3,3'-diyl)diphenanthrene (abbreviation: DPNS), 1,3,5-triphenyl-4,4'-diyldiphenanthrene (abbreviation: DPNS2), 1,3,5-tri(1 -pyrenyl)benzene (abbreviation: TPB3), etc. Among known substances, a compound having an energy gap larger than that of the guest material 121 is selected. One or more materials having gaps may be selected and used.

[0357] The light-emitting layer 120 may be composed of two or more layers. When the light-emitting layer 120 is formed by laminating the first light-emitting layer and the second light-emitting layer in this order from the hole transport layer side, a substance having hole transport properties is used as a host material for the first light-emitting layer, and a substance having hole transport properties is used as a host material for the second light-emitting layer For example, a substance having an electron transport property is used as the light emitting element.

[0358] In the light-emitting layer 120, the host material 122 is composed of one kind of compound. Alternatively, the light-emitting layer 120 may be made up of a single compound or a plurality of compounds. The layer may contain materials other than the host material 122 and the guest material 121 .

[0359] <Materials that can be used for the light-emitting layer 170> The light-emitting layer 170 can be made of any of the materials used for the light-emitting layer in the first embodiment. The materials that can be used for the light-emitting layer shown in Embodiment 1 can be used. By incorporating such a material into the light-emitting layer 170, a light-emitting element with high luminous efficiency can be fabricated. do.

[0360] Furthermore, there is no limitation on the color of light emitted from the light-emitting materials contained in the light-emitting layer 120 and the light-emitting layer 170. The light emitted from each of them is mixed and extracted from the device. Therefore, for example, if the emission colors of both are complementary to each other, the light-emitting element will emit white light. In consideration of the reliability of the light-emitting device, the light-emitting material contained in the light-emitting layer 120 The emission peak wavelength of the light-emitting material contained in the light-emitting layer 170 is preferably shorter than that of the light-emitting material contained in the light-emitting layer 170 .

[0361] The light-emitting unit 106, the light-emitting unit 108, and the charge generating layer 115 are formed by evaporation ( (including vacuum deposition), inkjet printing, coating, gravure printing, etc. can be done.

[0362] The structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. You can be there.

[0363] (Embodiment 3) In this embodiment mode, a light-emitting element having a different structure from those shown in Embodiment Modes 1 and 2 will be described. An example of this will be described below with reference to FIGS.

[0364] <Configuration example 1 of light-emitting element> 6(A) and 6(B) are cross-sectional views showing a light-emitting element of one embodiment of the present invention. In (B), the parts having the same functions as those shown in (A) are marked with the same hatching. In addition, parts with similar functions will be marked with similar symbols. In some cases, symbols are used and detailed descriptions thereof are omitted.

[0365] The light emitting element 260a and the light emitting element 260b shown in FIGS. 6A and 6B are light emitting elements that emit light toward the substrate 200. The light emitting element may be a bottom emission type light emitting element that extracts light from the substrate 200. It may also be a top emission type light emitting element that extracts light in the opposite direction. Note that one embodiment of the present invention is not limited to this. Light emitted from the light-emitting element may be projected from above and below the substrate 200. It may also be a dual emission type light emitting element in which light is extracted both upward and downward. .

[0366] When the light emitting element 260a and the light emitting element 260b are bottom emission type, the electrode 1 The electrode 101 preferably has a function of transmitting light. Alternatively, the light emitting element 260a and the light emitting element 260b may have a function of In the case of a top emission type, the electrode 101 preferably has a function of reflecting light. In addition, the electrode 102 preferably has a function of transmitting light.

[0367] The light emitting element 260a and the light emitting element 260b are formed by providing an electrode 101 and an electrode 102 on a substrate 200. Between the electrode 101 and the electrode 102, there is provided a light-emitting layer 123B and a light-emitting layer 123C. G and a light-emitting layer 123R. Also, the light-emitting layer 123B has a hole injection layer 111, a hole transport layer 112, It has an electron transport layer 118 and an electron injection layer 119 .

[0368] The light-emitting element 260b includes a conductive layer 101a and a conductive The conductive layer 101b is located above the conductive layer 101a, and the conductive layer 101c is located below the conductive layer 101a. That is, in the light emitting element 260b, the conductive layer 101a is made up of the conductive layer 101b and the conductive layer 101c. It has a sandwiched electrode 101 configuration.

[0369] In the light emitting element 260b, the conductive layer 101b and the conductive layer 101c are made of different materials. The electrodes 101 may be sandwiched between the same conductive material. In the case where the electrode 101 has a structure in which the pattern is formed by an etching process, This is preferable because it makes the synthesis easier.

[0370] In the light-emitting element 260b, the conductive layer 101b or the conductive layer 101c A configuration having only one of them may also be used.

[0371] The conductive layers 101a, 101b, and 101c of the electrode 101 are each The same structure and material as the electrode 101 or the electrode 102 shown in the first embodiment can be used. Cut.

[0372] In FIGS. 6(A) and 6(B), the region 221B sandwiched between the electrode 101 and the electrode 102, A partition wall 145 is provided between the region 221G and the region 221R. The partition wall 145 has insulating properties. The partition 145 covers the end of the electrode 101 and has an opening that overlaps the electrode. By providing the walls 145, the electrodes 101 on the substrate 200 in each region are arranged in an island shape. It becomes possible to separate them.

[0373] In addition, in the region where the light-emitting layer 123B and the light-emitting layer 123G overlap with the partition wall 145, Alternatively, the light-emitting layer 123G and the light-emitting layer 123R may have overlapping regions. In the region where they overlap with the partition wall 145, they may have regions where they overlap each other. The light-emitting layer 123R and the light-emitting layer 123B are mutually overlapping in the region where they overlap with the partition wall 145. It may have an overlapping area.

[0374] The partition wall 145 may be formed using an inorganic or organic material as long as it has insulating properties. The inorganic material may be silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, or the like. Examples of the organic material include silicon, aluminum oxide, and aluminum nitride. For example, photosensitive resin materials such as acrylic resin or polyimide resin can be used.

[0375] The silicon oxynitride film is a film whose composition contains more oxygen than nitrogen. Preferably, oxygen is 55 atomic % or more and 65 atomic % or less, and nitrogen is 1 atomic % or more and 20 atomic % or less. Silicon is 25 atomic % or more and 35 atomic % or less, and hydrogen is 0.1 atomic % or more and 10 atomic % or less The silicon nitride oxide film is a film that contains more nitrogen than oxygen as its composition. It refers to a film with a high content of nitrogen, preferably 55 atomic % to 65 atomic % and 100 atomic % of oxygen. % or more and 20 atomic % or less, silicon is 25 atomic % or more and 35 atomic % or less, hydrogen is 0.1 atomic % or more This refers to a film containing this element in a concentration range of 1 atomic % to 10 atomic %.

[0376] The light-emitting layers 123R, 123G, and 123B each exhibit a different color. For example, the light-emitting layer 123R may have a red light-emitting material. By including a light-emitting material having a function of emitting red light, the region 221R emits red light, and the light-emitting layer 12 Since the region 3G has a light-emitting material having a function of emitting green light, the region 221G emits green light. The light-emitting layer 123B contains a light-emitting material that exhibits blue color. B emits blue light. By using 0b in the pixels of a display device, a display device capable of full color display can be manufactured. The thickness of each light-emitting layer may be the same or different. good.

[0377] In addition, any one or more of the light-emitting layer 123B, the light-emitting layer 123G, and the light-emitting layer 123R The light-emitting layer is at least one of the light-emitting layer 130 and the light-emitting layer 135 shown in the first embodiment. It is preferable that the light-emitting element has one of the above structures. It is possible.

[0378] In addition, any one or more of the light-emitting layer 123B, the light-emitting layer 123G, and the light-emitting layer 123R The light-emitting layer may have a structure in which two or more layers are laminated.

[0379] As described above, at least one light-emitting layer has the light-emitting properties shown in the first and second embodiments. The light emitting element 260a or the light emitting element 260b having the light emitting layer is used in a display device. By using the organic EL element in the pixel of a display device, a display device with high luminous efficiency can be manufactured. A display device having the light-emitting element 260a or the light-emitting element 260b can reduce power consumption. can be done.

[0380] In addition, if an optical element (for example, a color filter, By providing a polarizing plate, an anti-reflection film, etc., the color purity of the light emitting element 260a and the light emitting element 260b can be improved. Therefore, the light emitting element 260a or the light emitting element 260b is effectively used. Alternatively, the color purity of the display device can be improved. Therefore, the light emitting element 260a or the light emitting element 260b can be prevented from reflecting external light. The contrast ratio of a display device having the element 260b can be increased.

[0381] Other configurations of the light emitting element 260a and the light emitting element 260b are the same as those in the embodiment. The structures of the light-emitting elements in Embodiments 1 and 2 may be referred to.

[0382] <Configuration example 2 of light-emitting element> Next, regarding a configuration example different from that of the light-emitting element shown in FIGS. 6(A) and 6(B), FIGS. 7(A) and 7(B) are shown. The following description will be given using this.

[0383] 7(A) and 7(B) are cross-sectional views showing a light-emitting element of one embodiment of the present invention. 6(A) and (B), the same symbols are used for parts having the same functions as those shown in FIGS. In some cases, the hatch pattern is used and the symbols are omitted. Also, parts with similar functions are indicated by The same reference numerals are used and detailed descriptions thereof may be omitted.

[0384] 7A and 7B show examples of the structure of a light-emitting element having a light-emitting layer between a pair of electrodes. The light emitting element 262a shown in (A) is a top-emitting (top-emitting) element that extracts light in the direction opposite to the substrate 200. The light emitting element 262b shown in FIG. 7(B) is a top-emission type light emitting element. However, the present invention One embodiment is not limited to this, and light emitted by the light emitting element may be emitted from the substrate 200 on which the light emitting element is formed. It may also be a dual emission type in which light is extracted from both the top and bottom.

[0385] The light emitting element 262a and the light emitting element 262b are formed by providing an electrode 101 and an electrode 102 on a substrate 200. , electrode 103, and electrode 104. Also, between electrode 101 and electrode 102, and At least a light-emitting layer is formed between the electrode 102 and the electrode 103 and between the electrode 102 and the electrode 104. The organic electroluminescent device has a layer 170, a light-emitting layer 190, and a charge-generating layer 115. The organic electroluminescent device also has a hole-injecting layer 111 and a , a hole transport layer 112, an electron transport layer 113, an electron injection layer 114, and a hole injection layer 116. , a hole transport layer 117 , an electron transport layer 118 , and an electron injection layer 119 .

[0386] The electrode 101 includes a conductive layer 101a and a conductive layer 101b that is in contact with the conductive layer 101a. The electrode 103 includes a conductive layer 103a and a conductive layer 103b on and in contact with the conductive layer 103a. The electrode 104 has a conductive layer 104a and a conductive layer 103b on the conductive layer 104a. and an insulating layer 104b.

[0387] The light emitting element 262a shown in FIG. 7(A) and the light emitting element 262b shown in FIG. 7(B) are The area 222B sandwiched between the electrode 101 and the electrode 102, and the area 222B sandwiched between the electrode 102 and the electrode 103 and a region 222R sandwiched between the electrode 102 and the electrode 104. The partition wall 145 has an insulating property. The partition wall 145 is provided between the electrode 101 and the electrode 1 The separator 145 covers the end of the electrode 103 and the electrode 104 and has an opening overlapping the electrode. By doing so, the electrodes on the substrate 200 in each region can be separated into islands. It becomes Noh.

[0388] The charge generation layer 115 is formed by adding an electron acceptor to a hole transporting material. or an electron transporting material to which an electron donor (donor) is added, In addition, when the conductivity of the charge generating layer 115 is as high as that of the pair of electrodes, In this case, carriers generated by the charge generating layer 115 flow to the adjacent pixels, Therefore, it is necessary to prevent adjacent pixels from emitting light incorrectly. To achieve this, the charge generation layer 115 is formed of a material having a lower conductivity than the pair of electrodes. preferable.

[0389] The light emitting element 262a and the light emitting element 262b are arranged in the regions 222B, 222G, and The optical element 224B and the optical element 224C are arranged in the direction in which the light emitted from the region 222R is extracted. The substrate 220 has the optical element 224G and the optical element 224R. The light emitted from the region 222B is emitted to the outside of the light emitting element through each optical element. The light coming from the region 222G is emitted through the optical element 224B. The light emitted through 224G and emitted from the region 222R is reflected by the optical element 224R. It is ejected.

[0390] Furthermore, the optical elements 224B, 224G, and 224R are configured to For example, the optical element 224B has a function of selectively transmitting light of a specific color. The light emitted from the region 222B through the optical element 22 is blue light. The light emitted from the area 222G via the optical element 4G is green light. The light emitted from the region 222R via the element 224R is red light.

[0391] The optical elements 224R, 224G, and 224B may include, for example, a colored layer ( Color filters, bandpass filters, multilayer filters, etc. can be used. In addition, a color conversion element can be applied to the optical element. The color conversion element is an optical element that converts light into light with a longer wavelength than the wavelength of the light. By using quantum dots, the color reproducibility of the display device can be improved. can be increased.

[0392] It should be noted that if other optical elements are arranged on the optical elements 224R, 224G, and 224B, Other optical elements may be provided, for example, a circular polarizing plate or an anti-reflection plate. The circular polarizer is placed in a position where the light emitted by the light emitting element of the display device is extracted. When the light source is provided on the side where the light source is located, the light incident from outside the display device is reflected inside the display device and Furthermore, by providing an anti-reflection film, the surface of the display device can be prevented from being irradiated. This reduces the amount of external light reflected by the display device, making it possible to clearly see the light emitted by the display device. It can be observed.

[0393] In addition, in FIG. 7(A)(B), the light emitted from each region via each optical element is Light exhibiting color (B), light exhibiting green (G), and light exhibiting red (R), respectively. This is shown schematically by dashed arrows.

[0394] In addition, a light-shielding layer 223 is provided between each optical element. The light-shielding layer 223 is formed to prevent light from entering from adjacent regions. It should be noted that the light-shielding layer 223 may not be provided. stomach.

[0395] The light-shielding layer 223 has a function of suppressing reflection of external light. The light-shielding layer 223 has a function of preventing the color mixture of light emitted from adjacent light-emitting elements. Examples include metals, resins containing black pigments, carbon black, metal oxides, and multiple metal oxides. A composite oxide containing a solid solution of such a material can be used.

[0396] The optical elements 224B and 224G overlap with the light-shielding layer 223. Alternatively, the optical element 224G and the optical element 224R is a region overlapping with the light-shielding layer 223, even if they have overlapping regions. Alternatively, the optical element 224R and the optical element 224B may overlap with the light-shielding layer 223. The regions may have overlapping regions.

[0397] The substrate 200 and the substrate 220 having the optical element are configured as in the first embodiment. Please take this into consideration.

[0398] Furthermore, the light emitting element 262a and the light emitting element 262b have a microcavity structure. .

[0399] <Microcavity structure> The light emitted from the light-emitting layer 170 and the light-emitting layer 190 is incident on a pair of electrodes (for example, electrode 10 The light emitting layer 170 and the light emitting layer 190 are resonated between the electrode 101 and the electrode 102. For example, the reflection area of ​​the electrode 101 is formed at a position where light of a desired wavelength is intensified. the optical distance from the reflecting area of ​​the electrode 102 to the light emitting area of ​​the light emitting layer 170; By adjusting the optical distance to the light emitting region, the amount of light emitted from the light emitting layer 170 can be reduced. In addition, the light emitted from the reflective region of the electrode 101 to the light emitting layer 190 can be intensified. and the optical distance from the reflective area of ​​the electrode 102 to the light-emitting area of ​​the light-emitting layer 190. By adjusting the optical distance, it is possible to obtain light of a desired wavelength from the light emitting layer 190. That is, the light can be intensified by using a plurality of light-emitting layers (here, the light-emitting layer 170 and the light-emitting layer In the case of a light emitting device in which the light emitting layer 170 and the light emitting layer 190 are stacked, the optical distances of the light emitting layer 170 and the light emitting layer 190 are It is preferable to optimize the separation.

[0400] In the light emitting element 262a and the light emitting element 262b, the conductive layer (conductive layer 1) is formed in each region. By adjusting the thickness of the conductive layer 101b, the conductive layer 103b, and the conductive layer 104b, the light-emitting layer 170 In addition, it is possible to enhance light of a desired wavelength among the light emitted from the light emitting layer 190. The thickness of at least one of the hole injection layer 111 and the hole transport layer 112 is made different in the region. This may intensify the light emitted from light-emitting layer 170 and light-emitting layer 190.

[0401] For example, the electrodes 101 to 104 are made of a conductive material having a function of reflecting light. When the refractive index is smaller than that of the light-emitting layer 170 or the light-emitting layer 190, the electrode The thickness of the conductive layer 101b of the electrode 101 is set so that the optical distance between the electrode 101 and the electrode 102 is m B λ B / 2(m B is a natural number, λ Brepresent the wavelengths of light to be intensified in region 222B, respectively) and Similarly, the thickness of the conductive layer 103b of the electrode 103 is adjusted to be equal to the thickness of the conductive layer 103b of the electrode 103. The optical distance between the electrode 102 is m G λ G / 2(m G is a natural number, λ G is strong in the area 222G The wavelength of the light emitted from the electrode 104 is adjusted to be 100 nm. The thickness of the electrode 104b is set such that the optical distance between the electrode 104 and the electrode 102 is m R λ R / 2(m R is self natural number, λ R and represent the wavelengths of the light to be intensified in the region 222R).

[0402] In addition, when it is difficult to precisely determine the reflective areas of the electrodes 101 to 104, By assuming that any region of the light-emitting layer 170 or the light-emitting electrode 101 to the electrode 104 is a reflective region, An optical path that enhances the light emitted from the light emitting layer 190 may be derived. When it is difficult to precisely determine the light-emitting region of the light-emitting layer 170 and the light-emitting layer 190, By assuming that any region of the light emitting layer 190 is a light emitting region, the light emitting layer 170 and the light emitting layer 190 An optical path that enhances the light emitted from the

[0403] As described above, a microcavity structure is provided, and the optical distance between a pair of electrodes in each region is adjusted. By adjusting the thickness, light scattering and absorption near each electrode are suppressed, resulting in high light extraction efficiency. The rate can be realized.

[0404] In the above structure, the conductive layer 101b, the conductive layer 103b, and the conductive layer 104b are optically It is preferable that the conductive layer 101b, the conductive layer 103b, and the conductive The materials constituting the layers 104a and 104b may be the same or different. When the same material is used for the conductive layer 101b, the conductive layer 103b, and the conductive layer 104b, the electrode 10 1. The pattern formation by the etching process in the process of forming the electrodes 103 and 104 is easy. In addition, the conductive layers 101b, 103b, and 104b are preferably Each of these may have a structure in which two or more layers are laminated.

[0405] The light emitting element 262a shown in FIG. 7(A) is a top emission type light emitting element, and therefore is conductive. The layer 101a, the conductive layer 103a, and the conductive layer 104a may have a function of reflecting light. It is also preferable that the electrode 102 has a function of transmitting light and a function of reflecting light. is preferred.

[0406] In addition, the light emitting element 262b shown in FIG. 7B is a bottom emission type light emitting element, and therefore is conductive. The layer 101a, the conductive layer 103a, and the conductive layer 104a have a function of transmitting light and a function of reflecting light. It is preferable that the electrode 102 has a function of reflecting light. preferable.

[0407] In the light-emitting element 262a and the light-emitting element 262b, the conductive layer 101a and the conductive layer 10 The same material may be used for the conductive layer 3a or the conductive layer 104a, or different materials may be used. When the same material is used for the conductive layer 101a, the conductive layer 103a, and the conductive layer 104a, the light emitting element The manufacturing costs of the conductive layer 101a and the light emitting element 262a and the light emitting element 262b can be reduced. The conductive layer 103a and the conductive layer 104a may each have a structure in which two or more layers are stacked. stomach.

[0408] In addition, the light-emitting layer 170 and the light-emitting layer 190 in the light-emitting element 262a and the light-emitting element 262b At least one of the above has at least one of the configurations shown in the first and second embodiments. By doing so, it is possible to manufacture a light-emitting element that exhibits high luminous efficiency. can be done.

[0409] The light-emitting layer 170 and the light-emitting layer 190 are, for example, the light-emitting layer 190a and the light-emitting layer 190b. In this way, two layers may be laminated on one or both sides. The first compound and the second compound are two types of luminescent materials that have the function of exhibiting different colors. By using each of them, multiple lights can be emitted simultaneously. The luminescent material used in each luminescent layer is selected so that the luminescence exhibited by 190 becomes white. This is preferable.

[0410] In addition, the light-emitting layer 170 or the light-emitting layer 190 may have a structure in which three or more layers are laminated on one side or both sides. The light-emitting layer may be made of any material, or may include a layer that does not contain a light-emitting material.

[0411] As described above, the present invention can be realized by using at least one of the structures of the light-emitting layer shown in Embodiments 1 and 2. By using the light-emitting element 262a or the light-emitting element 262b having the same in a pixel of a display device, A display device with high light efficiency can be manufactured. A display device including the element 262b can consume less power.

[0412] Other configurations of the light emitting element 262a and the light emitting element 262b are as follows: 260a or 260b, or the light-emitting element shown in the first and second embodiments. The configuration of the optical element should be taken into consideration.

[0413] <Method for manufacturing light-emitting elements> Next, a manufacturing method of a light-emitting element of one embodiment of the present invention will be described below with reference to FIGS. 8 and 9. Here, a method for manufacturing the light-emitting element 262a shown in FIG. do.

[0414] 8 and 9 are cross-sectional views illustrating a method for manufacturing a light-emitting element according to one embodiment of the present invention. .

[0415] The method for fabricating the light emitting element 262a described below includes seven steps, namely, first to seventh steps. do.

[0416] <First Step> The first step is to form an electrode (specifically, a conductive layer 101 constituting the electrode 101) of the light-emitting element. a, conductive layer 103a constituting electrode 103, and conductive layer 104a constituting electrode 104) is a step of forming the above on a substrate 200 (see FIG. 8(A)).

[0417] In this embodiment, a conductive layer having a function of reflecting light is formed on a substrate 200. The conductive layer is processed into a desired shape, whereby the conductive layer 101a, the conductive layer 103a, and the conductive layer 104a are formed. The conductive layer 104a is formed by using silver and palladium. The film is made of an alloy of Ag and copper (also called Ag-Pd-Cu film or APC). The conductive layer 101a, the conductive layer 103a, and the conductive layer 104a are formed by a process of processing the same conductive layer. Forming the wiring board through this process is preferable because it reduces the manufacturing cost.

[0418] It should be noted that a plurality of transistors may be formed on the substrate 200 before the first step. In addition, the plurality of transistors, the conductive layer 101a, the conductive layer 103a, and the conductive layer 104a may be electrically connected to each other.

[0419] <<Second Step>> In the second step, a light-transmitting layer is formed on the conductive layer 101a constituting the electrode 101. The conductive layer 101b is formed on the conductive layer 103a constituting the electrode 103. The conductive layer 103b is formed on the conductive layer 104a of the electrode 104. This is a step of forming a conductive layer 104b (see FIG. 8(B)).

[0420] In this embodiment, the conductive layers 101a and 103a, which have a function of reflecting light, 104a, and 101b, respectively, are provided on the conductive layers 101b, 103b, and 104a, respectively, which have a light transmitting function. By forming the electrode 104b, the electrode 101, the electrode 103, and the electrode 104 are formed. The conductive layers 101b, 103b, and 104b are made of ITSO films.

[0421] The conductive layers 101b, 103b, and 104b having a function of transmitting light are formed multiple times. By forming the microcapsules in multiple steps, it is possible to form the microcapsules in each area. The conductive layers 101b, 103b, and 104b can be formed to a thickness that provides a cavity structure. Cut.

[0422] <Third Step> The third step is to form the partition walls 145 that cover the edges of the electrodes of the light-emitting element ( See Figure 8(C)).

[0423] The partition wall 145 has an opening so as to overlap with the electrode. In this embodiment, the partition wall 145 is made of a polyimide resin. Use fat.

[0424] In the first to third steps, the EL layer (layer containing an organic compound) is not damaged. Since there is no risk of this, various film forming methods and microfabrication techniques can be applied. The method uses a sputtering method to form a reflective conductive layer, and then uses a lithography method to form a reflective conductive layer. A pattern is formed on the conductive layer, and then the pattern is formed by dry etching or wet etching. The conductive layer is processed into an island shape, whereby the conductive layer 101a constituting the electrode 101 and the electrode 10 A conductive layer 103a constituting the electrode 3 and a conductive layer 104a constituting the electrode 104 are formed. Thereafter, a transparent conductive film is formed by sputtering, and then a lithography method is used. Then, a pattern is formed on the transparent conductive film, and then the pattern is removed by wet etching. The transparent conductive film is then processed into islands to form electrodes 101, 103, and 104. do.

[0425] <Fourth Step> The fourth step is to form a hole injection layer 111, a hole transport layer 112, an emissive layer 190, an electron transport layer This is a step of forming a layer 113, an electron injection layer 114, and a charge generation layer 115 (see FIG. 9(A)). see).

[0426] The hole injection layer 111 is formed by co-evaporating a hole transporting material and a material containing an acceptor material. Co-evaporation is the process of depositing different materials on different surfaces. The hole transport layer 112 is a vapor deposition method in which the hole It can be formed by vapor deposition of a transport material.

[0427] The light-emitting layer 190 may be purple, blue, blue-green, green, yellow-green, yellow, orange, or red. The resulting film is formed by depositing at least one luminescent guest material selected from the following: As the guest material, a light-emitting organic material that exhibits fluorescence or phosphorescence can be used. In addition, the light-emitting layer having the structure shown in Embodiment 1 and Embodiment 2 can be used. It is preferable that the light-emitting layer 190 has a two-layer structure. The light-emitting layers preferably contain light-emitting materials that emit light of different colors.

[0428] The electron transporting layer 113 can be formed by evaporating a substance with a high electron transporting property. The electron injection layer 114 can be formed by evaporating a material with high electron injection properties. It is possible.

[0429] The charge generation layer 115 is made of a material in which an electron acceptor is added to a hole transporting material. or a material in which an electron donor (donor) is added to an electron transporting material. It can be formed by

[0430] <5th step> The fifth step is to deposit the hole injection layer 116, the hole transport layer 117, the light emitting layer 170, and the electron transport layer 118. This is a step of forming the insulating layer 118, the electron injection layer 119, and the electrode 102 (see FIG. 9B).

[0431] The hole injection layer 116 is formed using the same material and method as the hole injection layer 111 described above. The hole transport layer 117 can be formed by the above-described hole transport layer 11. It can be formed using the same materials and methods as in 2.

[0432] The light-emitting layer 170 may be purple, blue, blue-green, green, yellow-green, yellow, orange, or red. The resulting film is formed by depositing at least one luminescent guest material selected from the following: The guest material can be a light-emitting organic compound that exhibits fluorescence or phosphorescence. In addition, the light-emitting layer having the structure shown in Embodiment 1 and Embodiment 2 can be used. It is preferable that at least one of the light-emitting layer 170 and the light-emitting layer 190 is It is preferable that the light-emitting layer has the configuration shown in Form 1. In addition, the light-emitting layer 170 and the light-emitting layer 1 90 preferably contains luminescent organic compounds that have the function of exhibiting different luminescence from each other. .

[0433] The electron transport layer 118 is formed using the same material and method as the electron transport layer 113 described above. The electron injection layer 119 can be formed by the above-described electron injection layer 11. It can be formed using the same materials and methods as in 4.

[0434] The electrode 102 is formed by stacking a reflective conductive film and a light-transmitting conductive film. The electrode 102 can be formed as a single layer structure or a stacked layer structure. Good too.

[0435] Through the above steps, regions 222 are formed on the electrodes 101, 103, and 104, respectively. A light-emitting device having regions 222B, 222G, and 222R is formed on substrate 200.

[0436] <Sixth Step> In the sixth step, the light-shielding layer 223, the optical element 224B, and the optical element 224 are formed on the substrate 220. This is a step of forming the optical element 224G and the optical element 224R (see FIG. 9(C)).

[0437] The light-shielding layer 223 is formed by forming a resin film containing a black pigment in a desired area. On the plate 220 and the light-shielding layer 223, an optical element 224B, an optical element 224G, and an optical element 224G are provided. As the optical element 224B, a resin film containing a blue pigment is applied to a desired area. In addition, as the optical element 224G, a resin film containing a green pigment is formed in a desired area. In addition, the optical element 224R is formed by forming a resin film containing a red pigment in a desired area. do.

[0438] <Seventh Step> The seventh step is to separate the light emitting element formed on the substrate 200 and the light emitting element formed on the substrate 220. The light-shielding layer 223, the optical element 224B, the optical element 224G, and the optical element 224R are bonded together. This is a process of joining the components together and sealing them with a sealant (not shown).

[0439] Through the above steps, the light-emitting element 262a shown in FIG. 7(A) can be formed.

[0440] Note that the structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. You can be there.

[0441] (Fourth embodiment) In this embodiment, a display device of one embodiment of the present invention will be described with reference to FIGS. Reveal.

[0442] <Display device configuration example 1> 10A is a top view showing the display device 600, and FIG. 10B is a diagram showing the display device 600 shown in FIG. 10A along the dashed line. The display device 600 is a cross-sectional view taken along the line AB and the dashed line CD. It has a signal line driver circuit portion 601, a scanning line driver circuit portion 603, and a pixel portion 602. The signal line driver circuit portion 601, the scanning line driver circuit portion 603, and the pixel portion 602 are It has the function of controlling the light emission of the element.

[0443] The display device 600 also includes an element substrate 610, a sealing substrate 604, a sealant 605, The device has an area 607 surrounded by a sealing material 605, wiring 608, and an FPC 609. do.

[0444] The lead wiring 608 is connected to the signal line driver circuit portion 601 and the scanning line driver circuit portion 603. This is the wiring for transmitting the input signal, and is connected to the external input terminal FPC609. It receives the FP signal, clock signal, start signal, reset signal, etc. Although only C609 is shown, FPC609 has a printed wiring board (PWB). A wired wiring board may be installed.

[0445] The signal line driver circuit portion 601 includes an N-channel transistor 623 and a P-channel transistor A CMOS circuit is formed by combining this transistor 624. The path section 601 or the scanning line driving circuit section 603 may be implemented by various CMOS circuits, PMOS circuits, or In this embodiment, a driving circuit section is provided on the substrate. Although the display device shown has the formed driver and pixel on the same surface, this is not necessarily required. In addition, the drive circuit section can be formed externally rather than on the substrate.

[0446] The pixel portion 602 includes a switching transistor 611 and a current control transistor. a lower part electrically connected to the drain of the current control transistor 612; A partition wall 614 is formed to cover the edge of the lower electrode 613. The partition wall 614 can be made of a positive photosensitive acrylic resin film.

[0447] In order to improve the covering property, the partition wall 614 is provided with a curved surface having a curvature at the upper end or the lower end. For example, the partition wall 614 is made of a positive photosensitive acrylic. In this case, only the upper end of the partition wall 614 is curved to have a radius of curvature (0.2 μm or more and 3 μm or less). It is preferable that the partition wall 614 is made of a negative photosensitive resin or a polyimide. Any of the photosensitive resins of the di-type can be used.

[0448] The structure of the transistors (transistors 611, 612, 623, and 624) is For example, a staggered transistor may be used. There is no particular limitation on the polarity, and it has N-channel and P-channel transistors. and either an N-channel transistor or a P-channel transistor. A structure consisting of only one of the two may also be used. For example, an amorphous semiconductor film or a crystalline semiconductor film can be used. Semiconductor materials include group 14 (silicon, etc.) semiconductors, compound semiconductors (oxide As the transistor, for example, An energy gap of 2 eV or more, preferably 2.5 eV or more, and more preferably 3 eV or more By using the oxide semiconductor, the off-state current of the transistor can be reduced. As the oxide semiconductor, In-Ga oxide, In-M-Zn oxide (M is , aluminum (Al), gallium (Ga), yttrium (Y), zirconium (Zr ), lanthanum (La), cerium (Ce), tin (Sn), hafnium (Hf), or nickel Examples include neodymium (Nd).

[0449] An EL layer 616 and an upper electrode 617 are formed on the lower electrode 613. The lower electrode 613 functions as an anode, and the upper electrode 617 functions as a cathode. do.

[0450] The EL layer 616 can be formed by a deposition method using a deposition mask, an inkjet method, or a spin coating method. The EL layer 616 can be formed by various methods such as a low-temperature method. The compound may be a molecular compound or a polymer compound (including an oligomer or a dendrimer).

[0451] The lower electrode 613, the EL layer 616, and the upper electrode 617 form a light-emitting element 618. The light emitting element 618 has the structure of any one of the first to third embodiments. In addition, when a plurality of light-emitting elements are formed in a pixel portion, the same as those in Embodiments 1 to 4 are preferably used. The light-emitting element according to the third embodiment and the light-emitting element having other structures are both included. That's fine.

[0452] In addition, by bonding the sealing substrate 604 to the element substrate 610 with the sealing material 605, The light-emitting element is disposed in an area 607 surrounded by the element substrate 610, the sealing substrate 604, and the sealing material 605. The region 607 is filled with a filler. In addition to being filled with an inert gas (nitrogen, argon, etc.), it can also be used as a sealing material 605. They may also be filled with UV or heat curable resins that can be used for various applications, such as PVC ( Polyvinyl chloride) resin, acrylic resin, polyimide resin, epoxy resin, Silicone resin, PVB (Polyvinyl Butyral) resin, or EVA (Ethylene Vinyl A recess is formed in the sealing substrate, and a desiccant (acetate) resin is placed therein. By providing this, deterioration due to the influence of moisture can be suppressed, which is a preferable configuration.

[0453] In addition, the optical element 621 is disposed below the sealing substrate 604 so as to overlap the light emitting element 618. In addition, a light-shielding layer 622 is provided below the sealing substrate 604. The optical element and the light-shielding layer 621 and the light-shielding layer 622 are respectively the optical element and the light-shielding layer shown in the third embodiment. The same configuration may be used.

[0454] It is preferable to use epoxy resin or glass frit for the sealing material 605. In addition, it is desirable that these materials be as impermeable to moisture and oxygen as possible. In addition, the material used for the sealing substrate 604 may be a glass substrate, a quartz substrate, or an FRP (Fiber Reinforced Plastic) substrate. Reinforced Plastics), PVF (Polyvinyl Fluoride), Poly A plastic substrate made of ester, acrylic or the like can be used.

[0455] As described above, the light emitting element and the optical element described in any of the first to third embodiments are used. A display device can be obtained.

[0456] <Configuration example 2 of the display device> Next, another example of the display device will be described with reference to FIGS. 11(A), 11(B) and 12. 11A, 11B, and 12 are cross-sectional views of display devices according to embodiments of the present invention. .

[0457] FIG. 11(A) shows a substrate 1001, an underlying insulating film 1002, a gate insulating film 1003, a gate Electrodes 1006, 1007, 1008, a first interlayer insulating film 1020, a second interlayer insulating film 10 21, peripheral portion 1042, pixel portion 1040, driving circuit portion 1041, lower electrode 10 of light-emitting element 24R, 1024G, 1024B, partition wall 1025, EL layer 1028, upper electrode of light-emitting element 1026, a sealing layer 1029, a sealing substrate 1031, a sealing material 1032, etc. are shown. .

[0458] In addition, in FIG. 11(A), as an example of an optical element, a colored layer (a red colored layer 1034R, A green colored layer 1034G and a blue colored layer 1034B are provided on a transparent substrate 1033. A light-shielding layer 1035 may be further provided. The base material 1033 is aligned and fixed to the substrate 1001. is covered with an overcoat layer 1036. In FIG. 11(A), the colored layer Since the light that passes through the screen is red, green, and blue, images can be displayed using three color pixels.

[0459] In FIG. 11B, as an example of an optical element, a colored layer (a red colored layer 1034R, a green colored layer The colored layer 1034G and the blue colored layer 1034B are formed between the gate insulating film 1003 and the first interlayer insulating film. In this example, the colored layer is formed between the substrate 1001 and the film 1020. It may be provided between the substrates 1031 .

[0460] In FIG. 12, as an example of an optical element, a colored layer (a red colored layer 1034R, a green colored layer 1034G, blue colored layer 1034B) between the first interlayer insulating film 1020 and the second interlayer insulating film In this example, the colored layer is formed between the substrate 1001 and the sealing substrate 1021. It may be provided between the plates 1031.

[0461] In the display device described above, the substrate 1001 side on which the transistors are formed is The display device has a structure for extracting light (bottom emission type), but The display device may also have a structure in which light is extracted (top emission type).

[0462] <Configuration example 3 of the display device> An example of a cross-sectional view of a top-emission type display device is shown in Figures 13(A) and 13(B). 11(A) and 11(B) are cross-sectional views illustrating a display device of one embodiment of the present invention. 12.) and the driving circuit section 1041, the peripheral section 1042, etc. shown in FIG. 12 are omitted in the illustration.

[0463] In this case, the substrate 1001 can be a substrate that does not transmit light. Until the connection electrode that connects to the anode of the optical element is fabricated, it is a bottom emission type display device. Then, a third interlayer insulating film 1037 is formed to cover the electrode 1022. This insulating film may also have a role of planarization. In addition to the same material as the interlayer insulating film 2, various other materials can be used.

[0464] The lower electrodes 1024R, 1024G, and 1024B of the light-emitting element are anodes here, but Also, top emission type displays as shown in Figure 13(A)(B) can be used. In the case of a device, the lower electrodes 1024R, 1024G, and 1024B have a function of reflecting light. In addition, an upper electrode 1026 is provided on the EL layer 1028. The electrode 1026 has a function of reflecting light and a function of transmitting light. A microcavity structure is adopted between 24G, 1024B and the upper electrode 1026, It is desirable to increase the light intensity at a particular wavelength.

[0465] In the top emission structure shown in FIG. 13(A), the colored layer (red colored layer 1034 A sealing substrate 1031 provided with a green colored layer 1034R, a green colored layer 1034G, and a blue colored layer 1034B The sealing substrate 1031 has a shielding layer positioned between the pixels. An optical layer 1035 may be provided. Note that the sealing substrate 1031 may be a light-transmitting substrate. It is suitable.

[0466] In addition, in FIG. 13(A), a plurality of light emitting elements and colored light emitting elements are provided. Although the configuration in which a layer is provided is shown as an example, the present invention is not limited to this. For example, as shown in FIG. In this case, the green color layer is not provided, and only the red color layer 1034R and the blue color layer 1034B are provided. It is also possible to use a configuration in which a full color display is performed using three colors, red, green, and blue. In this way, when a light emitting element and a colored layer are provided for each of the light emitting elements, reflection of external light can be reduced. On the other hand, as shown in FIG. 13(B), In the case where a red colored layer and a blue colored layer are provided without providing a colored layer of green, Since there is little energy loss in the light emitted from the light-emitting element, power consumption can be reduced. This has a positive effect.

[0467] <Display device configuration example 4> The display device described above has a configuration having sub-pixels of three colors (red, green, and blue). A structure with four color sub-pixels (red, green, blue, yellow, or red, green, blue, white) 14 to 16 show the lower electrodes 1024R, 1024G, 1024B, 14(A), (B) and 15 show the configuration of a display device having 1024Y. A structure in which light is extracted from the substrate 1001 side where the transistor is formed (bottom emission type) 16(A) and 16(B) show a structure in which light is extracted to the sealing substrate 1031 side ( It is a top-emission display device.

[0468] FIG. 14(A) shows the optical element (colored layer 1034R, colored layer 1034G, colored layer 1034B 14 is an example of a display device in which a colored layer 1034Y is provided on a transparent substrate 1033. (B) shows the optical element (colored layer 1034R, colored layer 1034G, colored layer 1034B, colored layer 1034Y) is formed between the gate insulating film 1003 and the first interlayer insulating film 1020. 15 shows an example of the optical element (colored layer 1034R, colored layer 1034G, The color layer 1034B and the color layer 1034Y are formed between the first interlayer insulating film 1020 and the second interlayer insulating film 1032. 021.

[0469] The colored layer 1034R transmits red light, the colored layer 1034G transmits green light, and the colored layer The colored layer 1034B has a function of transmitting blue light, and the colored layer 1034Y has a function of transmitting yellow light. The ability to transmit multiple colors of light selected from blue, green, yellow, and red. The colored layer 1034Y transmits a plurality of light beams selected from blue, green, yellow, and red. When the colored layer 1034Y has a function of transmitting light, the light transmitted through the colored layer 1034Y may be white. Since the light emitting element that emits white light has high luminous efficiency, it is preferable to use the light emitting element that emits white light in the display having the colored layer 1034Y. The device can reduce power consumption.

[0470] In the top emission type display device shown in FIG. 16, the lower electrode 1024Y In the light-emitting element having the same structure, the upper electrode 1026 is connected to the light-emitting element 1026 in the same manner as in the display device of FIG. Among them, a configuration having a microcavity structure is preferable. Now, the colored layers (red colored layer 1034R, green colored layer 1034G, blue colored layer 103 The sealing can be performed by a sealing substrate 1031 provided with a yellow colored layer 1034Y. do.

[0471] The light emitted through the microcavity and the yellow colored layer 1034Y is in the yellow region. Yellow is a color with high visibility, so yellow light is emitted. The light-emitting element exhibiting this has high luminous efficiency. , power consumption can be reduced.

[0472] In addition, in FIG. 16(A), a plurality of light emitting elements and colored light emitting elements are provided. Although the configuration in which a layer is provided is shown as an example, the present invention is not limited to this. For example, as shown in FIG. , the yellow colored layer is not provided, and the red colored layer 1034R, the green colored layer 1034G, and the blue colored layer 1034R are provided. A colored layer 1034B is provided to allow the four colors of red, green, blue, and yellow, or red, green, blue, and white. As shown in FIG. 16(A), a light-emitting element and the light-emitting element When a colored layer is provided on each optical element, it is possible to suppress the reflection of external light. On the other hand, as shown in FIG. 16(B), a light emitting element and a red coloring layer are not provided. When a colored layer of a color, a green colored layer, and a blue colored layer are provided, yellow or white Since there is little energy loss in the light emitted from the light-emitting element, power consumption can be reduced. This has a positive effect.

[0473] <Display Device Configuration Example 5> Next, a display device according to another embodiment of the present invention is shown in FIG. 17. FIG. 17 shows the same display device as FIG. 10(A 17 is a cross-sectional view taken along dashed lines AB and CD. In this regard, parts having the same functions as those shown in FIG. 10(B) are denoted by the same reference numerals, and their details are shown in the same manner as those shown in FIG. 10(B). Detailed explanations will be omitted.

[0474] The display device 600 shown in FIG. 17 includes an element substrate 610, a sealing substrate 604, and a sealing material 60 The region 607 surrounded by 5 has sealing layers 607a, 607b, and 607c. For example, one or more of the sealing layers 607a, 607b, and 607c may include For example, PVC (polyvinyl chloride) resin, acrylic resin, polyimide resin, epoxy resin, silicone resin, PVB (polyvinyl butyral) resin, or EVA Resins such as ethylene vinyl acetate resins can be used. silicon oxynitride, silicon nitride oxide, silicon nitride, aluminum oxide, aluminum nitride Alternatively, an inorganic material such as aluminum may be used. By forming the layer c, it is possible to suppress deterioration of the light emitting element 618 due to impurities such as water. It is preferable to form the sealing layer 607a, the sealing layer 607b, and the sealing layer 607c. The cooling material 605 does not need to be provided.

[0475] In addition, the sealing layer 607a, the sealing layer 607b, and the sealing layer 607c may be any one or two. Alternatively, four or more sealing layers may be formed. Impurities such as these may penetrate from the outside of the display device 600 to the light emitting element 618 inside the display device. In addition, when the sealing layer is multi-layered, the sealing layer may be made of a resin and an inorganic material. It is preferable to laminate the material.

[0476] <Display Device Configuration Example 6> The display devices shown in Configuration Examples 1 to 4 in this embodiment include optical elements. However, in one embodiment of the present invention, an optical element does not necessarily have to be provided.

[0477] The display device shown in FIG. 18(A)(B) has a structure in which light is extracted to the sealing substrate 1031 side (transistor). 18A shows a display device of a top emission type (top emission type). 18B is an example of a display device having a light-emitting layer 1028G and a light-emitting layer 1028B. A surface having an optical layer 1028R, an emissive layer 1028G, an emissive layer 1028B, and an emissive layer 1028Y. This is an example of a display device.

[0478] The light-emitting layer 1028R emits red light, the light-emitting layer 1028G emits green light, and The light-emitting layer 1028B has a function of emitting blue light. or a function of exhibiting multiple luminescence selected from blue, green, and red. The light emitted by the light-emitting layer 1028Y may be white. Since the light-emitting element that emits light has high luminous efficiency, the display device having the light-emitting layer 1028Y has high luminous efficiency. Power consumption can be reduced.

[0479] The display devices shown in FIGS. 18(A) and 18(B) each have an EL layer that emits light of different colors. Since the colored layer is provided in the pixel, it is not necessary to provide a colored layer that serves as an optical element.

[0480] The sealing layer 1029 is made of, for example, a PVC (polyvinyl chloride) resin or an acrylic resin. resin, polyimide resin, epoxy resin, silicone resin, PVB (polyvinyl bromide) Resins such as ethylene vinyl acetate (EVA) resins can be used. In addition, silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride Alternatively, an inorganic material such as aluminum oxide or aluminum nitride may be used. By forming the insulating layer, deterioration of the light emitting element due to impurities such as water can be suppressed, which is preferable.

[0481] The sealing layer 1029 may be any one or two, or may be four or more sealing layers. By forming the sealing layer in multiple layers, impurities such as water can be prevented from entering the display device from the outside. This is preferable because it can effectively prevent the particles from penetrating into the inside of the display device. In the case of a multi-layer structure, a preferable structure is one in which a resin and an inorganic material are laminated.

[0482] The sealing substrate 1031 may have any function as long as it has a function of protecting the light-emitting element. Therefore, a flexible substrate or film can be used for the sealing substrate 1031.

[0483] Note that the configuration shown in this embodiment may be appropriately combined with other embodiments or other configurations in this embodiment. Combinations are possible.

[0484] (Embodiment 5) In this embodiment, a display device including a light-emitting element of one embodiment of the present invention will be described with reference to FIGS. The explanation will be ...

Claims

1. A light-emitting layer having a first material that is a light-emitting material and a second material that has a function of dispersing the first material, an energy difference between a LUMO level and a HOMO level of the first material is larger than an energy difference between a LUMO level and a HOMO level of the second material; the first material is a phosphorescent material; the second material has at least one of a pyrimidine skeleton, a pyrazine skeleton, a pyridazine skeleton, and a triazine skeleton; the second material has at least one of an acridine skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a furan skeleton, a thiophene skeleton, a pyrrole skeleton, and an aromatic amine skeleton; The second material has a difference between a singlet excitation energy level and a triplet excitation energy level of more than 0 eV and not more than 0.2 eV. Light emitting element.

2. A light-emitting layer having a first material that is a light-emitting material and a second material having a function of dispersing the first material, the LUMO level of the first material is higher than the LUMO level of the second material; the HOMO level of the first material is lower than the HOMO level of the second material; the first material is a phosphorescent material; the second material has at least one of a pyrimidine skeleton, a pyrazine skeleton, a pyridazine skeleton, and a triazine skeleton; the second material has at least one of an acridine skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a furan skeleton, a thiophene skeleton, a pyrrole skeleton, and an aromatic amine skeleton; The second material has a difference between a singlet excitation energy level and a triplet excitation energy level of more than 0 eV and not more than 0.2 eV. Light emitting element.

3. A light-emitting layer having a first material that is a light-emitting material and a second material having a function of dispersing the first material, an energy difference between a LUMO level and a HOMO level of the first material is larger than an energy difference between a LUMO level and a HOMO level of the second material; the first material is a phosphorescent material; the second material has at least one of a pyrimidine skeleton, a pyrazine skeleton, a pyridazine skeleton, and a triazine skeleton; the second material has at least one of an acridine skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a furan skeleton, a thiophene skeleton, a pyrrole skeleton, and an aromatic amine skeleton; The second material has a function of exhibiting thermally activated delayed fluorescence at room temperature. Light emitting element.

4. A light-emitting layer having a first material that is a light-emitting material and a second material that has a function of dispersing the first material, the LUMO level of the first material is higher than the LUMO level of the second material; the HOMO level of the first material is lower than the HOMO level of the second material; the first material is a phosphorescent material; the second material has at least one of a pyrimidine skeleton, a pyrazine skeleton, a pyridazine skeleton, and a triazine skeleton; the second material has at least one of an acridine skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a furan skeleton, a thiophene skeleton, a pyrrole skeleton, and an aromatic amine skeleton; The second material has a function of exhibiting thermally activated delayed fluorescence at room temperature. Light emitting element.

5. An emission layer having a first material which is a guest material and a second material which is a host material, an energy difference between a LUMO level and a HOMO level of the first material is larger than an energy difference between a LUMO level and a HOMO level of the second material; the first material is a phosphorescent material; the second material has at least one of a pyrimidine skeleton, a pyrazine skeleton, a pyridazine skeleton, and a triazine skeleton; the second material has at least one of an acridine skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a furan skeleton, a thiophene skeleton, a pyrrole skeleton, and an aromatic amine skeleton; The second material has a difference between a singlet excitation energy level and a triplet excitation energy level of more than 0 eV and not more than 0.2 eV. Light emitting element.

6. An emission layer having a first material which is a guest material and a second material which is a host material, the LUMO level of the first material is higher than the LUMO level of the second material; the HOMO level of the first material is lower than the HOMO level of the second material; the first material is a phosphorescent material; the second material has at least one of a pyrimidine skeleton, a pyrazine skeleton, a pyridazine skeleton, and a triazine skeleton; the second material has at least one of an acridine skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a furan skeleton, a thiophene skeleton, a pyrrole skeleton, and an aromatic amine skeleton; The second material has a difference between a singlet excitation energy level and a triplet excitation energy level of more than 0 eV and not more than 0.2 eV. Light emitting element.

7. An emission layer having a first material which is a guest material and a second material which is a host material, an energy difference between a LUMO level and a HOMO level of the first material is larger than an energy difference between a LUMO level and a HOMO level of the second material; the first material is a phosphorescent material; the second material has at least one of a pyrimidine skeleton, a pyrazine skeleton, a pyridazine skeleton, and a triazine skeleton; the second material has at least one of an acridine skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a furan skeleton, a thiophene skeleton, a pyrrole skeleton, and an aromatic amine skeleton; The second material has a function of exhibiting thermally activated delayed fluorescence at room temperature. Light emitting element.

8. An emission layer having a first material which is a guest material and a second material which is a host material, the LUMO level of the first material is higher than the LUMO level of the second material; the HOMO level of the first material is lower than the HOMO level of the second material; the first material is a phosphorescent material; the second material has at least one of a pyrimidine skeleton, a pyrazine skeleton, a pyridazine skeleton, and a triazine skeleton; the second material has at least one of an acridine skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a furan skeleton, a thiophene skeleton, a pyrrole skeleton, and an aromatic amine skeleton; The second material has a function of exhibiting thermally activated delayed fluorescence at room temperature. Light emitting element.

9. In any one of claims 1 to 8, the first material comprises iridium; Light emitting element.

10. A light-emitting layer having a first material that is a light-emitting material and a second material that has a function of dispersing the first material, an energy difference between a LUMO level and a HOMO level of the first material is larger than an energy difference between a LUMO level and a HOMO level of the second material; the first material is an iridium complex; the second material has at least one of a pyrimidine skeleton, a pyrazine skeleton, a pyridazine skeleton, and a triazine skeleton; the second material has at least one of an acridine skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a furan skeleton, a thiophene skeleton, a pyrrole skeleton, and an aromatic amine skeleton; The second material has a difference between a singlet excitation energy level and a triplet excitation energy level of more than 0 eV and not more than 0.2 eV. Light emitting element.

11. A light-emitting layer having a first material that is a light-emitting material and a second material that has a function of dispersing the first material, the LUMO level of the first material is higher than the LUMO level of the second material; the HOMO level of the first material is lower than the HOMO level of the second material; the first material is an iridium complex; the second material has at least one of a pyrimidine skeleton, a pyrazine skeleton, a pyridazine skeleton, and a triazine skeleton; the second material has at least one of an acridine skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a furan skeleton, a thiophene skeleton, a pyrrole skeleton, and an aromatic amine skeleton; The second material has a difference between a singlet excitation energy level and a triplet excitation energy level of more than 0 eV and not more than 0.2 eV. Light emitting element.

12. A light-emitting layer having a first material that is a light-emitting material and a second material having a function of dispersing the first material, an energy difference between a LUMO level and a HOMO level of the first material is larger than an energy difference between a LUMO level and a HOMO level of the second material; the first material is an iridium complex; the second material has at least one of a pyrimidine skeleton, a pyrazine skeleton, a pyridazine skeleton, and a triazine skeleton; the second material has at least one of an acridine skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a furan skeleton, a thiophene skeleton, a pyrrole skeleton, and an aromatic amine skeleton; The second material has a function of exhibiting thermally activated delayed fluorescence at room temperature. Light emitting element.

13. A light-emitting layer having a first material that is a light-emitting material and a second material having a function of dispersing the first material, the LUMO level of the first material is higher than the LUMO level of the second material; the HOMO level of the first material is lower than the HOMO level of the second material; the first material is an iridium complex; the second material has at least one of a pyrimidine skeleton, a pyrazine skeleton, a pyridazine skeleton, and a triazine skeleton; the second material has at least one of an acridine skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a furan skeleton, a thiophene skeleton, a pyrrole skeleton, and an aromatic amine skeleton; The second material has a function of exhibiting thermally activated delayed fluorescence at room temperature. Light emitting element.

14. An optical emitting layer having a first material which is a guest material and a second material which is a host material, an energy difference between a LUMO level and a HOMO level of the first material is larger than an energy difference between a LUMO level and a HOMO level of the second material; the first material is an iridium complex; the second material has at least one of a pyrimidine skeleton, a pyrazine skeleton, a pyridazine skeleton, and a triazine skeleton; the second material has at least one of an acridine skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a furan skeleton, a thiophene skeleton, a pyrrole skeleton, and an aromatic amine skeleton; The second material has a difference between a singlet excitation energy level and a triplet excitation energy level of more than 0 eV and not more than 0.2 eV. Light emitting element.

15. An optical emitting layer having a first material which is a guest material and a second material which is a host material, the LUMO level of the first material is higher than the LUMO level of the second material; the HOMO level of the first material is lower than the HOMO level of the second material; the first material is an iridium complex; the second material has at least one of a pyrimidine skeleton, a pyrazine skeleton, a pyridazine skeleton, and a triazine skeleton; the second material has at least one of an acridine skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a furan skeleton, a thiophene skeleton, a pyrrole skeleton, and an aromatic amine skeleton; The second material has a difference between a singlet excitation energy level and a triplet excitation energy level of more than 0 eV and not more than 0.2 eV. Light emitting element.

16. An optical emitting layer having a first material which is a guest material and a second material which is a host material, an energy difference between a LUMO level and a HOMO level of the first material is larger than an energy difference between a LUMO level and a HOMO level of the second material; the first material is an iridium complex; the second material has at least one of a pyrimidine skeleton, a pyrazine skeleton, a pyridazine skeleton, and a triazine skeleton; the second material has at least one of an acridine skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a furan skeleton, a thiophene skeleton, a pyrrole skeleton, and an aromatic amine skeleton; The second material has a function of exhibiting thermally activated delayed fluorescence at room temperature. Light emitting element.

17. An optical emitting layer having a first material which is a guest material and a second material which is a host material, the LUMO level of the first material is higher than the LUMO level of the second material; the HOMO level of the first material is lower than the HOMO level of the second material; the first material is an iridium complex; the second material has at least one of a pyrimidine skeleton, a pyrazine skeleton, a pyridazine skeleton, and a triazine skeleton; the second material has at least one of an acridine skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a furan skeleton, a thiophene skeleton, a pyrrole skeleton, and an aromatic amine skeleton; The second material has a function of exhibiting thermally activated delayed fluorescence at room temperature. Light emitting element.

18. In any one of claims 1 to 17, the second material is present in a greater amount by weight than the first material; Light emitting element.

19. In any one of claims 1 to 18, Substantially no light emission from the second material is observed. Light emitting element.

20. A light-emitting element according to any one of claims 1 to 19, At least one of a color filter or a transistor; A display device having the above configuration.

21. A display device according to claim 20, At least one of a housing or a touch sensor; An electronic device having the

22. A light-emitting element according to any one of claims 1 to 19, At least one of a housing or a touch sensor; A lighting device having the above structure.

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