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

Abstract

To provide a light-emitting element that has high luminous efficiency and drives at low voltage.SOLUTION: A light-emitting element includes a guest material and a host material. The LUMO level of the guest material is lower than the LUMO level of the host material. The energy difference between the LUMO level and the HOMO level of the guest material is larger than the energy difference between the LUMO level and the HOMO level of the host material. The guest material has a function of converting the triplet excitation energy into light emission. The energy difference between the LUMO level of the guest material and the HOMO level of the host material is more than or equal to the energy of the light emission from 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. The display device also has the advantage of having a high response speed.

[0005] A light-emitting element in which 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 device (for example, an organic EL device), applying a voltage between a pair of electrodes causes light to flow from the cathode Electrons are injected from the cathode and holes are injected from the anode into the luminescent EL layer, causing a current to flow. The injected electrons and holes are then recombined to excite the light-emitting organic material. The excited light-emitting organic material is then in a luminescent state, 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. The energy difference depends on the energy difference between the excited state and the singlet state. In a light-emitting element using an organic material that emits phosphorescence, the triplet excitation energy is Therefore, the singlet excited state and triplet excited state formed by organic materials are converted into light-emitting energy. When the energy difference between the excited state and the non-excited state is large, the energy required to excite the organic material is The energy of the light is higher than that of the light emission by the amount of energy corresponding to the energy difference. The energy difference between the energy required to excite the organic material and the energy of light emission This affects the element characteristics as an increase in the driving voltage of the light emitting element. Techniques for reducing the pressure are being developed (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, there is a need for a highly reliable phosphorescent light-emitting element that exhibits 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. Energetic iridium complexes with pyridine skeletons or nitrogen-containing five-membered heterocyclic skeletons have been reported. Iridium complexes having a pyridine skeleton or a nitrogen-containing five-membered heterocycle as a ligand are known. The skeletons have high triplet excitation energy but low electron-accepting properties, so these skeletons The iridium complexes with the ligands have high HOMO and LUMO levels, and the hole carriers While ions are easily injected, electron carriers are difficult to inject. Development of iridium complexes with complex ligands has been progressing.

[0011] On the other hand, iridium complexes with ligands having highly electron-accepting skeletons have high HOMO levels and The LUMO level is low, making it easy for electron carriers to be injected, but difficult for hole carriers to be injected. Therefore, excitation by direct recombination of carriers is difficult, and it is difficult to efficiently emit light from a light-emitting element. It can be difficult to get them to do this.

[0012] 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

[0013] 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]

[0014] One aspect of the present invention is to provide a light-emitting device having a host material that can efficiently excite a phosphorescent material. It is an element.

[0015] Therefore, one embodiment of the present invention is a light-emitting element having a guest material and a host material. Therefore, the LUMO level of the guest material is lower than the LUMO level of the host material. The energy difference between the LUMO level and the HOMO level of the host material is The energy difference between the triplet excitation energy and the guest material is larger than the energy difference between the triplet excitation energy and the guest material. The light-emitting element has a function of being able to emit light.

[0016] Another embodiment of the present invention is a light-emitting element including a guest material and a host material. Therefore, the LUMO level of the guest material is lower than that of the host material, and the L The energy difference between the UMO level and the HOMO level is the difference between the LUMO level and the HOMO level of the host material. The energy difference between the triplet excitation and the guest material is larger than the energy difference between the triplet excitation and the guest material, and the guest material converts the triplet excitation energy into luminescence. The LUMO level of the guest material and the HOMO level of the host material are The energy difference is the transition energy calculated from the absorption edge in the absorption spectrum of the guest material. It is a light-emitting element with more than 1000kJ / s.

[0017] Another embodiment of the present invention is a light-emitting element including a guest material and a host material. Therefore, the LUMO level of the guest material is lower than that of the host material, and the L The energy difference between the UMO level and the HOMO level is the difference between the LUMO level and the HOMO level of the host material. The energy difference between the triplet excitation and the guest material is larger than the energy difference between the triplet excitation and the guest material, and the guest material converts the triplet excitation energy into luminescence. The LUMO level of the guest material and the HOMO level of the host material are is a light-emitting element in which the energy difference between the guest material and the guest material is equal to or greater than the light emission energy of the guest material.

[0018] In each of the above structures, the energy between the LUMO level and the HOMO level of the guest material is The difference is calculated from the transition energy calculated from the absorption edge in the absorption spectrum of the guest material. It is preferable that the difference between the LUMO level and the HOMO level of the guest material is 0.4 eV or more. The energy difference is preferably 0.4 eV or more larger than the luminescence energy of the guest material. I wish.

[0019] In each of the above structures, the host material has a singlet excitation energy level and a triplet excitation energy level. It is preferable that the difference between the host energy level and the host material is greater than 0 eV and 0.2 eV or less. The material preferably has the function of exhibiting thermally activated delayed fluorescence at room temperature.

[0020] In each of the above structures, the host material has a function of providing excitation energy to the guest material. In addition, it is preferable that the emission spectrum of the host material is similar to that of the guest material. It is preferable that the wavelength region overlaps with the absorption band on the lowest energy side in the absorption spectrum of I wish.

[0021] In each of the above structures, the guest material preferably contains iridium. Preferably, the material exhibits luminescence.

[0022] In each of the above structures, the host material has a function of transporting electrons, The host material preferably has a function of transporting holes. The compound has a π-electron deficient heteroaromatic ring skeleton, and the host material has a π-electron rich heteroaromatic ring skeleton or It is preferable that the compound has at least one of a π-electron deficient heteroaromatic skeleton and an aromatic amine skeleton. The aromatic skeleton has at least one of a diazine skeleton and a triazine skeleton, and is a π-electron-rich type. The heteroaromatic ring skeleton includes the acridine skeleton, the phenoxazine skeleton, the phenothiazine skeleton, and the furan skeleton. It is preferable that the compound has at least one of a thiophene skeleton, a pyrrole skeleton, and a pyrrole skeleton.

[0023] In the light-emitting element according to each of the above configurations, the host material may be represented by the following structural formula (500) It is preferable that the compound is represented by any one of (503). [ka] Another embodiment of the present invention is a compound represented by any one of the following structural formulas (500) to (503): It is a compound that is [ka]

[0024] 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 the plurality of transistors. The electronic device has a display device and at least one of a housing and a touch sensor. Another aspect 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 including a light-emitting element. The term "light emitting device" as used herein also includes electronic devices having a light emitting device. The term "device" refers to an image display device or a light source (including lighting devices). Connectors, such as FPC (Flexible Printed Circuit), T Module with CP (Tape Carrier Package) attached, TC A module with a printed wiring board at the end of P, or a light emitting element with COG (Chip On Glass) Modules in which ICs (integrated circuits) are directly mounted using the "On Glass" method are also included in the scope of this invention. This is one aspect. [Effects of the Invention]

[0025] 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.

[0026] 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]

[0027] [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 schematic 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 schematic 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 a cross-sectional view and a schematic diagram illustrating a correlation between energy levels of a light-emitting layer according to one embodiment of the present invention; [Figure 6] 1A and 1B are a schematic cross-sectional view of a light-emitting element of one embodiment of the present invention and a schematic diagram illustrating the correlation of energy levels in a light-emitting layer. [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 and 1B are schematic cross-sectional views of 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 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 11] 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 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 schematic cross-sectional views illustrating a display device according to one embodiment of the present invention. [Figure 20] 1A and 1B are a block diagram and a circuit diagram illustrating a display device of 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 circuit diagram illustrating a pixel circuit of a display device according to one embodiment of the present invention. [Figure 23] FIG. 1 is a perspective view illustrating an example of a touch panel of one embodiment of the present invention. [Figure 24]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 25] FIG. 1 is a cross-sectional view illustrating an example of a touch panel of one embodiment of the present invention. [Figure 26] 1A and 1B are a block diagram and a timing chart of a touch sensor according to one embodiment of the present invention. [Figure 27] FIG. 1 is a circuit diagram of a touch sensor according to one embodiment of the present invention. [Figure 28] FIG. 1 is a perspective view illustrating a display module 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] 1A to 1C illustrate electronic devices of one embodiment of the present invention. [Figure 32] FIG. 1 is a perspective view illustrating a display device according to one embodiment of the present invention. [Figure 33] 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 34] FIG. 1 is a cross-sectional view illustrating a light-emitting device according to one embodiment of the present invention. [Figure 35] 1A to 1C illustrate a lighting device and an electronic device according to one embodiment of the present invention. [Figure 36] 1A to 1C illustrate a lighting device according to one embodiment of the present invention. [Figure 37] 1A and 1B are cross-sectional views illustrating a light-emitting element according to an embodiment. [Figure 38] FIG. 10 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 39] FIG. 10 is a graph showing luminance-voltage characteristics of a light-emitting element according to an example. [Figure 40] FIG. 10 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 41] FIG. 10 is a graph showing power efficiency vs. luminance characteristics of a light-emitting element according to an embodiment. [Figure 42] 10A and 10B are graphs illustrating electroluminescence spectra of light-emitting elements according to Examples. [Figure 43] FIG. 1 is a diagram illustrating an emission spectrum of a host material according to an example. [Figure 44] FIG. 10 is a diagram illustrating transient fluorescence characteristics of a host material according to an example. [Figure 45] 4A and 4B are diagrams illustrating absorption spectra and emission spectra of guest materials according to an example. [Figure 46] FIG. 10 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 47] FIG. 10 is a graph showing luminance-voltage characteristics of a light-emitting element according to an example. [Figure 48] FIG. 10 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 49] FIG. 10 is a graph showing power efficiency vs. luminance characteristics of a light-emitting element according to an embodiment. [Figure 50] 10A and 10B are graphs illustrating electroluminescence spectra of light-emitting elements according to Examples. [Figure 51] FIG. 1 is a diagram illustrating an emission spectrum of a host material according to an example. [Figure 52] 4A and 4B are diagrams illustrating absorption spectra and emission spectra of guest materials according to an example. [Figure 53] FIG. 10 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 54] FIG. 10 is a graph showing luminance-voltage characteristics of a light-emitting element according to an example. [Figure 55] FIG. 10 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 56] FIG. 10 is a graph showing power efficiency vs. luminance characteristics of a light-emitting element according to an embodiment. [Figure 57] 10A and 10B are graphs illustrating electroluminescence spectra of light-emitting elements according to Examples. [Figure 58] FIG. 1 is a diagram illustrating an emission spectrum of a host material according to an example. [Figure 59] FIG. 1 is a diagram illustrating an emission spectrum of a host material according to an example. [Figure 60]FIG. 1 shows a 1H NMR chart of N-(4-biphenyl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-N-{4-[3-(dibenzo[f,h]quinoxalin-2-yl)phenyl]phenyl}amine (abbreviation: 2mpFBiBPDBq). [Figure 61] FIG. 1 shows the results of LC / MS analysis of 2mpFBiBPDBq. [Figure 62] FIG. 1 shows the absorption spectrum and emission spectrum of a toluene solution of 2mpFBiBPDBq. [Figure 63] FIG. 1 shows the absorption and emission spectra of a solid thin film of 2mpFBiBPDBq. [Figure 64] FIG. 1 shows a 1H NMR chart of N-(4-biphenyl)-N-(4-{6-[3-(dibenzo[f,h]quinoxalin-2-yl)phenyl]dibenzofuran-4-yl}phenyl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: 2mFBiPDBfPDBq). [Figure 65] FIG. 1 shows the absorption spectrum and emission spectrum of a toluene solution of 2mFBiPDBfPDBq. [Figure 66] Figure 1 shows the absorption and emission spectra of a solid thin film of 2mFBiPDBfPDBq. [Figure 67] 1H NMR chart of 4-[3-(dibenzo[f,h]quinoxalin-2-yl)phenyl]-4'-(9-phenyl-9H-carbazol-3-yl)-triphenylamine (abbreviation: 2mpPCBABPDBq). [Figure 68] FIG. 1 shows the absorption spectrum and emission spectrum of a toluene solution of 2mpPCBABPDBq. [Figure 69] FIG. 1 shows the absorption and emission spectra of a solid thin film of 2mpPCBABPDBq. [Figure 70] 1 shows a 1H NMR chart of N-phenyl-N-[(1,1'-biphenyl)-4-yl]-N-{4-[3-(dibenzo[f,h]quinoxalin-2-yl)phenyl]phenyl}amine (abbreviation: 2mpBPABPDBq). [Figure 71]FIG. 1 shows the results of LC / MS analysis of 2mpBPABPDBq. [Figure 72] FIG. 1 shows the absorption spectrum and emission spectrum of a toluene solution of 2mpBPABPDBq. [Figure 73] FIG. 1 shows the absorption and emission spectra of a solid thin film of 2mpBPABPDBq. DETAILED DESCRIPTION OF THE INVENTION

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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

[0033] 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.

[0034] 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.

[0035] 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

[0036] In this specification and the like, room temperature refers to a temperature between 0°C and 40°C.

[0037] In this specification, the blue wavelength region refers to wavelengths of 400 nm or more and less than 500 nm. blue emission has at least one emission spectrum peak in this region. The green wavelength range is the wavelength range of 500 nm or more and 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.

[0038] (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.

[0039] <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.

[0040] FIG. 1A is a schematic cross-sectional view of a light-emitting element 150 of one embodiment of the present invention.

[0041] 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. .

[0042] 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.

[0043] 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. .

[0044] 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, reduce 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

[0045] 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 FIG.

[0046] 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 .

[0047] 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.

[0048] <Light-emitting mechanism of light-emitting element 1> Next, the light emitting mechanism of the light emitting layer 130 will be described below.

[0049] 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 flow from the cathode and holes flow from the anode. 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.

[0050] Light emission from the guest material 131 is obtained through the following two processes. ·(α) Direct recombination process (β) Energy transfer process

[0051] ≪(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) The energy difference depends on the energy of the singlet excited state. On the other hand, since the guest material 131 is a phosphorescent material, the energy of the triplet excited state corresponds to Therefore, the guest material 131 forms a singlet excited state and a triplet excited state. When the energy difference between the excited state and the singlet state is large, the energy required to excite the guest material 131 is The energy is higher than the light emission energy by the amount corresponding to the energy difference. It becomes.

[0052] 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.

[0053] 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.

[0054] <(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 G : S1 level of guest material 131 (phosphorescent material) T G : T1 level of guest material 131 (phosphorescent material) ·S H : S1 level of the host material 132 T H : T1 level of the host material 132

[0055] The carriers recombine in the host material 132, and the host material 132 reaches a singlet excited state. When the 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 , the singlet excited energy level (S H ) and triplet excited energy levels (T H ) to the triplet excited energy level (T G ) and move to the guest material The guest material 131 enters a triplet excited state. Light emission is obtained.

[0056] The singlet excitation energy level (SH ) and triplet excited energy Gee level (T H ) are the triplet excited energy levels (T G ) End In this way, the singlet excitation energy of the generated host material 132 is preferably and triplet excitation energy relative to the singlet excitation energy level (S H ) and triplet excited energy level (T H ) to the triplet excitation energy of guest material 131 Level (T G ) can efficiently transfer energy to

[0057] 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.

[0058] 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 oriented such that the triplet excited energy level (T H ) It is preferable to have a material with a triplet excitation energy level higher than Therefore, the triplet excitation energy of the host material 132 is less likely to be quenched, and the guest material 132 can be efficiently Energy transfer occurs to the substrate material 131.

[0059] In addition, the singlet excitation energy of the host material 132 is higher than the triplet excitation energy of the guest material 131. Energy level (T G ), the host material 13 In 2, the singlet excited energy level (S H ) and triplet excited energy level (T H )'s It is preferable that the energy difference is small.

[0060] FIG. 2B shows an energy band diagram of the guest material 131 and the host material 132. In FIG. 2(B), Guest(131) represents the guest material 131, and Hos t(132) represents the host material 132, and ΔE G is the LUMO level of the guest material 131 and H represents the energy difference with the OMO level, ΔE H is the LUMO level of the host material 132 and the HOM represents the energy difference with the O level, ΔE B is the LUMO level of the guest material 131 and the host material This is the notation and symbol that represents the energy difference from the HOMO level of 132.

[0061] The guest material 131 emits light with a short wavelength and high emission energy. To achieve this, the energy difference (ΔE G On the other hand, in the light emitting element 150, in order to reduce the driving voltage, 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.

[0062] 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 ) emits light with lower energy than the guest material. The energy difference (ΔE) between the LUMO level and the HOMO level of the material 131 G ) is the host material 13 The energy difference between the LUMO level and the HOMO level of 2 (ΔE H ) even if it is larger than , the luminescence energy (abbreviated as ΔE Em ) or absorption spectrum The transition energy (abbreviated as ΔE abs ) is ΔE H Is it equivalent to , the guest material 13 This allows the transfer of excitation energy to 1, and light emission can be obtained from the guest material 131. The present inventors found that the ΔE G However, guest material 131 exhibits The luminous energy (ΔE Em ) or the transition calculated from the absorption edge in the absorption spectrum Transfer energy (ΔE abs ), it is difficult to directly electrically excite the guest material131. In ΔE G Therefore, the driving voltage of the light-emitting element is However, in one embodiment of the present invention, ΔE H (ΔE G (smaller than The host material 132 is electrically excited by the electrical energy from the This generates an excited state of the guest material 131, allowing the guest to be excited with low driving voltage and high efficiency. Light can be emitted from the material 131. Therefore, the light-emitting element of one embodiment of the present invention can emit light. Light-onset voltage (luminance 1 cd / m 2 The voltage (which is larger than the voltage) is used to generate the light emitted by the guest material. Energy (ΔE Em ) can be made smaller than the voltage corresponding to ΔE G but, The luminescence energy (ΔE Em ) or in the absorption spectrum Transition energy (ΔE abs ) (e.g., In this case, the light emitting material is a blue light emitting material. Light energy (ΔE Em ) is the emission peak (maximum value, or shoulder) or the wavelength of the rising edge.

[0063] 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 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), among which iridium (Ir) is preferable. 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.

[0064] In order for the guest material 131 to be stable and highly reliable, the L The UMO level is preferably low, and for this purpose, the heavy metal atoms of the guest material 131 It is also preferable that the ligand to be coordinated to the nucleus has high electron-accepting property and a low LUMO level.

[0065] The guest material with the above structure is a molecule with a low LUMO level that easily accepts electrons. When the guest material 131 has a molecular structure that easily accepts electrons, The LUMO level of material 131 may be lower than the LUMO level of the host material 132. Furthermore, ΔE G is ΔE H If the HOMO level of the guest material 131 is larger than that of the host The HOMO level of the guest material 131 becomes lower than the HOMO level of the guest material 132. The energy difference between the HOMO level of the guest material 131 and the HOMO level of the host material 132 is The energy difference between the O level and the LUMO level of the host material 132 becomes larger.

[0066] Here, the LUMO level of the guest material 131 is lower than the LUMO level of the host material 132. When 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) ), the holes injected from the anode are injected into the host material 132 in the light-emitting layer 130. Therefore, electrons injected from the cathode 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 between the LUMO level of the guest material 131 and the HOMO level of the host material 132 -Difference (ΔE B ) is the luminescence energy (ΔE Em ) As the temperature increases, the generation of an exciplex formed between the guest material 131 and the host material 132 increases. In this case, the guest material 131 is unlikely to generate an excited state by itself, The light emitting efficiency of the light emitting element is reduced.

[0067] The above reaction can be represented by the following general formula (G11) or (G12).

[0068] H + +G - → (H·G) * (G11) H+G * → (H·G) * (G12)

[0069] General formula (G11) represents a compound in which the host material 132 accepts holes (H + ), guest material 131 accepts electrons (G - ) so that the host material 132 and the guest material 131 form an exciplex. ((H·G) * In addition, general formula (G12) is a reaction that produces Stock material 131 (G * ) interacts with the ground state host material 132(H) , the host material 132 and the guest material 131 form an exciplex ((H·G) * ) The host material 132 and the guest material 131 form an exciplex ((H·G) * ) is formed By this, the excited state (G * ) becomes difficult to generate.

[0070] The exciplex formed by the host material 132 and the guest material 131 is The energy difference (ΔE B ) roughly equivalent to However, the LUM of the guest material 131 The energy difference (ΔE B ) is the guest material The luminescence energy of 131 (ΔE Em ) or absorption edge in the absorption spectrum The transition energy (ΔE abs ) or more, the host material 132 and the guest The reaction of forming an exciplex with the guest material 131 can be suppressed, and the guest material 131 can be efficiently The present inventors have found that it is possible to obtain light emission with high efficiency. abs but ΔE B Since the guest material 131 is smaller, it is easier for the guest material 131 to receive excitation energy, and the host material Rather than forming an exciplex between 132 and the guest material 131, the guest material 131 is The state that receives energy and becomes excited is lower in energy and more stable.

[0071] As described above, the energy difference between the LUMO level and the HOMO level of the guest material 131 is -Difference (ΔE G ) is the energy difference between the LUMO and HOMO levels of the host material 132 ( ΔE H ), the absorption edge in the absorption spectrum of the guest material 131 The transition energy (ΔE abs ) is ΔE H If it is equal to or smaller than The excitation energy is efficiently transferred from the excited host material 132 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 fabricated with low voltage and high efficiency. At this time, ΔE G >ΔE H ≧ΔE abs (ΔE G is ΔE H Larger, ΔE H teeth ΔE absTherefore, the LUMO level of the guest material 131 and the HOM The energy difference between the O level (ΔE G ) in the absorption spectrum of the guest material 131 The transition energy (ΔE abs ) is larger than the merit of one embodiment of the present invention. More specifically, the LUMO level and the HOMO level of the guest material 131 are The energy difference between the G ) is the absorption edge in the absorption spectrum of the guest material 131. The transition energy (ΔE abs ) is preferably 0.3 eV or more larger than 0 It is more preferable that the luminescence energy of the guest material 131 is 0.4 eV or more. (ΔE Em ) is ΔE abs The LU of the guest material 131 is equal to or smaller than The energy difference between the MO level and the HOMO level (ΔE G ) is the luminescence exhibited by guest material 131. of energy (ΔE Em ) is preferably 0.3 eV or more larger, and 0.4 eV or more larger. It is more preferable.

[0072] Furthermore, the LUMO level of the guest material 131 is lower than the LUMO level of the host material 132. As mentioned above, when B ≧ΔE abs (ΔE B is ΔE abs or more), or ΔE B ≧ΔE Em (ΔE B is ΔE Em Therefore, ΔE G >ΔE H >ΔE B ≧ΔE abs (ΔE G is ΔE HLarger, ΔE H is ΔE B Larger, ΔE B is ΔE abs or more), or ΔE G >ΔE H >ΔE B ≧ΔE Em (ΔE G is ΔE H twist Large, ΔE H is ΔE B Larger, ΔE B is ΔE Em These are preferable. The above condition is also an important discovery in one embodiment of the present invention.

[0073] In addition, the energy difference between the LUMO level and the HOMO level of the host material 132 (ΔE H )teeth , the singlet excited energy level (S H ) is equal to or slightly larger than Singlet excited energy levels (S H ) is the triplet excited energy level (T H ) is larger than the triplet excited energy level (T H ) is a guest Triplet excited energy levels (T G ) is greater than ΔE G >ΔE H ≧S H >T H ≧T G (ΔE G is ΔE H Larger, ΔE H is S H That's all, S H is T H Bigger, T H is T G In addition, in the absorption spectrum of the guest material 131, The absorption at the absorption edge in the SiO2-doped ... When the absorption is related to the transition, ΔT G is ΔE abs The energy is equal to or slightly smaller than Therefore, ΔE G is ΔE abs In order for ΔE G and ΔE abs From the energy difference, S H and T H It is preferable that the energy difference between Specifically, S H and T H The energy difference between the eV or less, and more preferably, greater than 0 eV and less than or equal to 0.1 eV.

[0074] 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 H From S H The reverse intersystem crossing efficiency to S does not need to be high. H Light output from Since the molecular yield does not need to be high, a wide range of materials can be selected.

[0075] 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 H ) and triplet excited energy level (T H ) is a desirable difference. The value is usually greater than 0 eV and equal to or less than 0.2 eV.

[0076] 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.

[0077] Furthermore, when the host material 132 has a skeleton with strong donor properties, the electrons injected into the light-emitting layer 130 The holes are easily injected into the host material 132 and transported. When the emissive layer 130 has a skeleton with a strong acceptor property, the electrons injected into the emissive layer 130 are absorbed by the host material. This allows the excited state to be easily injected into the host material 132 and transported. This is preferable because it is easier to form.

[0078] The emission wavelength of the guest material 131 becomes shorter, and the emission energy (ΔE Em ) 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 smaller than H With just enough energy Since the photoresist material 131 can be excited, the power consumption of the light-emitting element can be reduced. Therefore, the transition calculated from the absorption edge in the absorption spectrum of the guest material 131 Energy (ΔE abs ) and the energy between the LUMO level and the HOMO level of the guest material 131. Energy difference (ΔE G ) and the larger the energy difference between them (i.e., blue light is emitted) In the case of a guest material exhibiting such a property), the effect of the light-emitting mechanism of one embodiment of the present invention becomes remarkable.

[0079] 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.

[0080] 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 0.3 eV or more and 0.8 eV or less. It is more preferable that the value is in the range of 0.4 eV or more and 0.8 eV or less, and it is more preferable that the value is in the range of 0.5 eV or more and 0.8 eV or less. It is more preferable that the energy of the light emitted by the guest material 131 is large in the range of 0.1 eV or less. Energy (ΔE Em ) is ΔE abs Since it is equal to or smaller than the guest material 13 The energy difference between the LUMO level and the HOMO level of 1 (ΔE G ) is presented by guest material 131 The energy of the emitted light (ΔE Em ) is larger in the range of 0.3 eV to 0.8 eV It is preferable that the value is larger than 0.4 eV and smaller than 0.8 eV, and more preferable that the value is larger than 0.5 eV. It is more preferable that the value is large within the range of 0.8 eV or more.

[0081] In addition, the LUMO level of the guest material 131 is lower than the LUMO level of the host material 132. Therefore, the guest material 131 functions as an electron trap in the light-emitting layer 130 . When the guest material 131 functions as an electron trap, it facilitates the carrier balance in the light-emitting layer. This is preferable because it can be easily controlled and the effect of extending the life can be obtained. If the LUMO level of material 131 is too low, the above-mentioned ΔE B However, Therefore, the energy difference between the LUMO level of the guest material 131 and the LUMO level of the host material 132 is The energy difference is preferably 0.05 eV or more and 0.4 eV or less. The energy difference between the MO level and the HOMO level of the host material 132 is preferably 0.05 eV or more, more preferably 0.1 eV or more, and even more preferably 0.2 eV or more. This facilitates injection of hole carriers into the host material 132. It is suitable.

[0082] 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, in the light-emitting layer 130, the excited state generated by the direct combination of carriers is Most of the electrons will exist as excited states formed by the host material 132. According to the configuration of one embodiment of the present invention, the excitation energy from the host material 132 to the guest material 131 is By making it easier for energy to move, the driving voltage of the light-emitting element can be reduced, and the light emission Efficiency can be improved.

[0083] In addition, from the relationship between the LUMO level and the HOMO level described above, the reduction potential of the guest material 131 The oxidation potential and the reduction potential of the host material 132 are preferably higher than the reduction potential of the host material 132. The potential can be measured by cyclic voltammetry (CV) .

[0084] 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.

[0085] <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.

[0086] <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) .

[0087]

number

[0088] 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.

[0089] 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).

[0090]

number

[0091] 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 .

[0092] 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.

[0093]

number

[0094] 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.

[0095] <Concept for enhancing energy transfer> In the energy transfer by the Förster mechanism, the energy transfer efficiency φ ET is Photon quantum yield φ (fluorescence quantum yield when discussing energy transfer from a singlet excited state, When discussing energy transfer from triplet excited states, a higher phosphorescence quantum yield is better. In addition, the emission spectrum of the host material 132 (which discusses energy transfer from the singlet excited state) The fluorescence spectrum in the case of the guest material 131 and the absorption spectrum (from the singlet ground state to the triplet state) It is preferable that the overlap with the absorption corresponding to the transition to the first excited state is large. It is also preferable that the molar absorption coefficient of the host material 131 is high. This means that the spectrum overlaps with the absorption band appearing on the longest wavelength side of the guest material 131. do.

[0096] 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 performed on the emission spectrum of the host material 132 and the longest wavelength side of the guest material 131. This is achieved by the overlap of the absorption bands of the

[0097] <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.

[0098] 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.

[0099] 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. .

[0100] 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.

[0101] 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. can be.

[0102] <Light-emitting mechanism of light-emitting elements 2> Next, the light emitting mechanism of the light emitting layer 135 will be described below.

[0103] 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.

[0104] Light emission from the guest material 131 is obtained through the following two processes. ·(α) Direct recombination process (β) Energy transfer process

[0105] 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.

[0106] <(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 A : S1 level of the host material 133 T A : T1 level of the host material 133

[0107] The carriers recombine in the host material 132, and the host material 132 reaches a singlet excited state. When the 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 The singlet excited energy level (S H ) and triplet excited energy levels ( T H ) to the triplet excited energy level (T G ) and move to the guest material The guest material 131 enters a triplet excited state. Light emission is obtained.

[0108] In addition, the excitation energy is efficiently transferred from the host material 132 to the guest material 131. To achieve this, the triplet excited energy level (T A ) is the host material 132 The triplet excited energy level (T H ) is preferably higher than the host material. The triplet excitation energy of the guest material 132 is less likely to be quenched, and the guest material 13 Energy transfer occurs to 1.

[0109] As shown in the energy band diagram in Figure 4(B), the LUMO level of the guest material 131 When the LUMO level is lower than the LUMO level of the host material 132, the light-emitting mechanism 1 of the light-emitting element is As mentioned above, the energy difference (ΔE G ) is the energy difference (ΔE H ) greater than It is preferable that the value is larger than ΔE H is the LUMO level of the guest material 131 and the LUMO level of the host material 132. Energy difference with the HOMO level (ΔE B ) is preferable.

[0110] The HOMO level of the host material 133 is lower than the HOMO level of the host material 132. and the LUMO level of the host material 133 is higher than the LUMO level of the guest material 131. 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 between the LUMO level of the guest material 131 and the HOMO level of the host material 132. Energy difference (ΔE B ) is larger than the host material 133 and the host material 13 2 to form an exciplex, and the host material 133 and the guest material 131 to form an exciplex. In FIG. 4(B), the reaction of forming Host (13 3) represents the host material 133, and other notations and symbols are the same as those in FIG. 2(B).

[0111] The difference between the HOMO level of the host material 133 and the HOMO level of the host material 132, and The difference between the LUMO level of the host material 133 and the LUMO level of the guest material 131 is The energy is preferably 0.1 eV or more, and more preferably 0.2 eV or more. By having an energy difference, the electrons injected from the pair of electrodes (electrode 101 and electrode 102) Electron and hole carriers are transported through the guest material 131 and the host material 132, respectively. This is preferable because it can be easily injected into the

[0112] The HOMO level of the host material 133 is higher than the HOMO level of the guest material 131. The LUMO level of the host material 133 may be higher or lower than the LUMO level of the host material 132. It can be higher or lower than the level.

[0113] The energy difference between the LUMO level and the HOMO level of the host material 133 is The energy difference (ΔE) between the LUMO level and the HOMO level of the material 132 H ) is preferable. At this time, the energy difference (ΔE H ) is the energy difference (ΔE G )Yo Since the carriers (holes and electrons) injected into the light-emitting layer 135 are smaller than the The excited state of the host material 133 and the guest material 131 is that they are excited singly. The host material 132 is more energetically stable when it forms an excited state than when it forms an excited state. Therefore, the excitation current generated by the direct recombination of carriers in the light-emitting layer 135 Most of the states will exist as excited states formed by the host material 132. Therefore, in the light-emitting layer 135, similarly to the configuration of the light-emitting layer 130, the host material 1 By facilitating the transfer of excitation energy from the excited state of 32 to the guest material 131, This allows the driving voltage of the light emitting element 152 to be reduced, and the light emitting efficiency to be increased.

[0114] 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 smaller than the energy difference between the LUMO level and the HOMO level of the host material 132. When 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, It is preferable that the material has a small energy difference between the energy level and the triplet excited energy level. In particular, it is preferable that the material is a thermally activated delayed fluorescent material.

[0115] In order to obtain efficient light emission from the guest material 131, the singlet excited electrons of the host material 133 must be Energy level (S A ) is the singlet excited energy level (S H ) That's all The triplet excited energy level (T A ) is the third of the host material 132 Singlet excited energy level (T H ) or more is preferable.

[0116] In addition, from the relationship between the LUMO level and the HOMO level described above, the oxidation potential of the host material 133 The oxidation potential of the host material 132 is higher than the reduction potential of the host material 133. It is preferable that the potential is lower than the reduction potential of the base material 131 .

[0117] 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.

[0118] 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.

[0119] <Material> Next, components of a light-emitting element according to one embodiment of the present invention will be described in detail below.

[0120] <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.

[0121] <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.

[0122] 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 It is preferable that the compound has an aromatic amine skeleton and a π-electron-deficient heteroaromatic ring skeleton. This facilitates the formation of donor-acceptor excited states within the molecule. The electron transporting property is set to be strong so that both donor property and acceptor property are strong in the molecule of the electron transporting material 132. It is preferable that the skeleton having the hole transporting property is directly bonded to the skeleton having the hole transporting property. Alternatively, a π-electron rich heteroaromatic ring skeleton or aromatic amine skeleton and a π-electron deficient heteroaromatic ring skeleton are It is preferable that the aromatic ring skeleton has a structure in which the bond is directly bonded to the aromatic ring skeleton. By strengthening both the ternary structure and the molecular orbitals in the HOMO of the host material 132, The overlap between the region and the region where the molecular orbitals in the LUMO are distributed can be reduced, The energies of the singlet and triplet excited energy levels of the host material 132 In addition, the triplet excitation energy level of the host material 132 can be reduced. This allows the position to be kept at a high energy level.

[0123] 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.

[0124] When the thermally activated delayed fluorescent material is composed of one kind of material, for example, the following material is used: It is possible.

[0125] 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.

[0126] [ka]

[0127] 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) and triazine skeleton The azine skeleton is preferred because it is stable and reliable. Among the skeletons that can be used, the acridine skeleton, the phenoxazine skeleton, the phenothiazine skeleton, and the furan skeleton are The thiophene skeleton and pyrrole skeleton are stable and reliable, so that a small number of these skeletons can be used. It is preferable that the furan skeleton has at least one. The thiophene skeleton is preferably a dibenzothiophene skeleton. The skeleton includes an indole skeleton, a carbazole skeleton, and a 9-phenyl-3,3'-bi- A 9H-carbazole skeleton is particularly preferred. The substance in which the π-electron-rich heteroaromatic ring is directly bonded to the π-electron-deficient heteroaromatic ring exhibits the donor property of the π-electron-rich heteroaromatic ring. The acceptor properties of both heteroaromatic rings are strong, and the levels of the singlet excited state and the triplet excited state are high. It is particularly preferred because the difference in the positions of the π-electron-deficient heteroaromatic rings is small. An aromatic ring to which an electron-withdrawing group such as an ano group is attached may also be used.

[0128] [ka]

[0129] 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.

[0130] 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. .

[0131] 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.

[0132] 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).

[0133] 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.

[0134] <Compound Example 1> The compound suitable for the light-emitting element of one embodiment of the present invention described above is represented by the following general formula (G0): It is a compound that can be

[0135] [ka]

[0136] 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 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 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.

[0137] 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.

[0138] 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 Examples of the alkyl group include a tert-butyl group, an n-hexyl group, and the like. 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.

[0139] In the compound represented by the general formula (G0), the benzofuropyrimidine skeleton is The benzothienopyrimidine skeleton is preferred. The skeleton is preferably a benzothieno[3,2-d]pyrimidine skeleton.

[0140] In the compound represented by the general formula (G0), one carbamate of the bicarbazole skeleton is At the 9-position of the zolyl group, either directly or via an arylene group, benzofuro[3,2-d] The pyrimidine skeleton or benzothieno[3,2-d]pyrimidine skeleton is bonded to the 4-position of the structure Compounds with this structure have both strong donor and acceptor properties and have 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 particularly preferred configuration. The compound is a compound represented by the following general formula (G1).

[0141] [ka]

[0142] In the above general formula (G1), Q represents oxygen or sulfur.

[0143] 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.

[0144] 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 Examples of the alkyl group include a tert-butyl group, an n-hexyl group, and the like. 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.

[0145] In the compound represented by general formula (G1), the bicarbazole skeleton is 3,3'- It is a bi-9H-carbazole skeleton, and one of the carbazolyl groups of the bicarbazole skeleton is At the 9-position, a benzofuro[3,2-d]pyrimidine skeleton is attached directly or via an arylene group. Compounds with a structure bonded to the 4-position of the benzothieno[3,2-d]pyrimidine skeleton Since the material has excellent carrier transport properties, light-emitting devices using it can be driven at low voltage. This is a preferred configuration. The compound is a compound represented by the following general formula (G2).

[0146] [ka]

[0147] In the above general formula (G2), Q represents oxygen or sulfur.

[0148] Also, R 1 ~R20 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.

[0149] 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 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 Examples of the alkyl group include a tert-butyl group, an n-hexyl group, and the like. 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.

[0150] In the compound represented by general formula (G1) or (G2), a bicarbazole skeleton and a benzofuropyrimidine skeleton or a benzothienopyrimidine skeleton are directly bonded to each other. In the case of a compound having such a structure, the band gap is improved and it is possible to synthesize it with high purity. In addition, since the compound has excellent carrier transport properties, it is possible to use The light-emitting element can be driven at a low voltage.

[0151] 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).

[0152] [ka]

[0153] In the above general formula (G3), Q represents oxygen or sulfur.

[0154] 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.

[0155] 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 Examples of the alkyl group include a tert-butyl group, an n-hexyl group, and the like. 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.

[0156] [ka]

[0157] In the above general formula (G4), Q represents oxygen or sulfur.

[0158] 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.

[0159] 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 Examples of the alkyl group include a tert-butyl group, an n-hexyl group, and the like. 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.

[0160] 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.

[0161] [ka]

[0162] [ka]

[0163] In the above 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. A specific example is a hydroxyl group.

[0164] 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.

[0165] [ka]

[0166] [ka]

[0167] 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 group, a cycloalkyl group, and a cycloalkyl group. 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:

[0168] 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.

[0169] [ka]

[0170] [ka]

[0171] In addition, R in the above general formulas (G1) and (G2) 1 ~R 20 , R in general formula (G0) 1 ~ R 15 , 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.

[0172] [ka]

[0173] <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.

[0174] [ka]

[0175] [ka]

[0176] [ka]

[0177] [ka]

[0178] [ka]

[0179] [ka]

[0180] [ka]

[0181] [ka]

[0182] Compound Example 2 The host material 132 has a singlet excited energy level and a triplet excited energy level. The energy difference between the two is small, and the reverse intersystem crossing efficiency does not necessarily need to be high. The yield does not have to be high, and the compound does not have to have the function of exhibiting thermally activated delayed fluorescence. The host material 132 has a structure having a π-electron-rich heteroaromatic ring or an aromatic amine structure. At least one of the two and the skeleton having the π-electron-deficient heteroaromatic ring is an m-phenylene group or It is preferable that the bond is formed via a structure having at least one o-phenylene group. Alternatively, it is preferable that the bond is via a biphenyldiyl group. via an arylene group having at least one -phenylene group or o-phenylene group It is preferable that the arylene group has a structure in which the aryl group is bonded to the aryl group, and the arylene group is preferably a biphenyldiyl group. This is more preferable because the T1 level of the host material 132 can be increased. In this case, the skeleton having a π-electron deficient heteroaromatic ring is a diazine skeleton (π at least one of a methylimidine skeleton, a pyrazine skeleton, a pyridazine skeleton, and a triazine skeleton The skeleton having a π-electron rich heteroaromatic ring is preferably an acridine. skeleton, phenoxazine skeleton, phenothiazine skeleton, furan skeleton, thiophene skeleton, and It is preferable that the olefin skeleton is at least one of a dibenzofuran skeleton and a furan skeleton. The zofran skeleton is preferred, and the thiophene skeleton is preferred, for example, a dibenzothiophene skeleton. The pyrrole skeleton includes an indole skeleton, a carbazole skeleton, and a 9-phenyl A 3,3'-bi-9H-carbazole skeleton is particularly preferred. As the amine, so-called tertiary amines having no NH bond are preferred, and triarylamines are particularly preferred. The aryl group of the triarylamine skeleton is preferably A substituted or unsubstituted aryl group having 6 to 13 carbon atoms is preferred, and a phenyl group, a naphthyl group, Examples include a fluorenyl group.

[0183] 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.

[0184] [ka]

[0185] 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).

[0186] [ka]

[0187] 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.

[0188] [ka]

[0189] The aromatic amine skeleton (specifically, triarylamine skeleton), π-electron-rich heterocyclic Aromatic ring skeleton (specifically, acridine skeleton, phenoxazine skeleton, phenothiazine skeleton, a ring having at least one of a lanthanide skeleton, a thiophene skeleton, and a pyrrole skeleton, and a π-electron deficient heteroaromatic ring skeleton (specifically, at least one of a diazine skeleton and a triazine skeleton) or the above general formulas (401) to (417), general formulas (201) to (2 18) and general formulae (301) to (315) may have a substituent. Examples of the group include an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and A substituted or unsubstituted aryl group having 6 to 12 carbon atoms may also be used as a substituent. 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 6 carbon atoms, an n-hexyl group, and the like. Specific examples of the alkyl group include a cyclopropyl group, a cyclobutyl group, and a cyclopentyl group. and cyclohexyl groups. Specific examples of the alkyl group include a phenyl group, a naphthyl group, and a biphenyl group. The above substituents may be bonded to each other to form a ring. For example, the carbon atom at the 9th position of the fluorene skeleton has two phenyl groups as substituents. In this case, the phenyl groups are bonded to each other to form a spirofluorene skeleton. In addition, when the compound is unsubstituted, it is advantageous in terms of ease of synthesis and the cost of raw materials. do.

[0190] 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:

[0191] 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.

[0192] 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 or unsubstituted alkyl group having 6 or more carbon atoms; It represents an aryl 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 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.

[0193] 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.

[0194] 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) In addition, the alkyl group or the aryl group can be used as the alkyl group or the aryl group. The groups are not limited to these.

[0195] Specific structures of the compounds listed above include, for example, the following structural formulas (500) to (50 3) is an example of a compound represented by the formula:

[0196] [ka]

[0197] 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.

[0198] <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.

[0199] 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 low LUMO level and the energy of the LUMO and HOMO levels of the host material 132 The host material 132 has an energy difference between the LUMO level and the HOMO level that is higher than the energy difference between the LUMO level and the HOMO level. and the guest material 131 (phosphorescent material). A light-emitting element having high conductivity and driven at a low voltage can be obtained.

[0200] Examples of substances having a blue or green emission peak include tris{2-[5-(2 -methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazo {3-yl-κN2]phenyl-κC}iridium(III) (abbreviation: Ir(mpp tz-dmp)3), tris(5-methyl-3,4-diphenyl-4H-1,2,4-trimethyl- Triazolato)iridium(III) (abbreviation: Ir(Mptz)3), tris[4-(3- Biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazolato]i Iridium(III) (abbreviation: Ir(iPrptz-3b)3), tris[3-(5-biphenyl] (phenyl)-5-isopropyl-4-phenyl-4H-1,2,4-triazolato]irid Ir(III) (abbreviated as Ir(iPr5btz)3), a 4H-triazole skeleton and organometallic iridium complexes having (OC-6-22)-tris{5-cyano-2-[ 4-(2,6-diisopropylphenyl)-5-(2-methylphenyl)-4H-1,2 ,4-triazol-3-yl-κN 2 ]phenyl-κC}iridium(III) (abbreviation :fac-Ir(mpCNptz-diPrp)3), (OC-6-21)-Tris{5 -cyano-2-[4-(2,6-diisopropylphenyl)-5-(2-methylphenyl )-4H-1,2,4-triazol-3-yl-κN 2 ]phenyl-κC}iridium (III) (abbreviation: mer-Ir(mpCNptz-diPrp)3), tris{2-[ 4-(4-cyano-2,6-diisobutylphenyl)-5-(2-methylphenyl)-4 H-1,2,4-triazol-3-yl-κN 2 ]phenyl-κC}iridium(II I) (abbreviation: Ir(mpptz-diBuCNp)3) -triazole-based organometallic iridium complexes and tris[3-methyl-1-(2 -methylphenyl)-5-phenyl-1H-1,2,4-triazolato]iridium(I II) (abbreviation: Ir(Mptz1-mp)3), tris(1-methyl-5-phenyl-3 -propyl-1H-1,2,4-triazolato)iridium(III) (abbreviation: Ir(P Organometallic iridium complexes with 1H-triazole skeletons, such as rptz1-Me3) body and fac-tris[1-(2,6-diisopropylphenyl)-2-phenyl-1H -imidazole]iridium(III) (abbreviation: Ir(iPrpmi)3), tris[3 -(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridin imidazoline, such as iridium(III) (abbreviation: Ir(dmpimpt-Me)3) Organometallic iridium complexes with a diol skeleton and bis[2-(4',6'-difluorophenyl)- Nyl)pyridinato-N,C 2’ ]iridium(III) tetrakis(1-pyrazolyl)borate bis[2-(4',6'-difluorophenyl)pyridinate] (abbreviation: FIr6) -N,C 2’ ]Iridium(III) picolinate (abbreviation: FIrpic), bis{2- [3',5'-Bis(trifluoromethyl)phenyl]pyridinato-N,C 2’}Iriji Ir(III) picolinate (abbreviation: Ir(CF3ppy)2(pic)), bis[2- (4',6'-Difluorophenyl)pyridinato-N,C 2’ ]Iridium(III) Phenyl groups with electron-withdrawing groups such as cetylacetonate (abbreviation: FIr(acac)) Organometallic iridium complexes having pyridine derivatives as ligands are also included. Nitrogen-containing structures such as 4H-triazole, 1H-triazole and imidazole skeletons Organometallic iridium complexes with five-membered heterocyclic rings have high triplet excitation energies. This is particularly preferable because it is excellent in reliability and luminous efficiency.

[0201] Furthermore, examples of substances having a green or yellow emission peak include tris(4-methylphenyl) Ir(mppm)3, Tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: I r(tBuppm)3), (acetylacetonato)bis(6-methyl-4-phenylpyridine) Iridium(III) (abbreviation: Ir(mppm)2(acac)), (acetylacetonate ruacetonato)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)), ( acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III)( Organometallic iridium compounds with pyrimidine skeletons, such as Ir(dppm)2(acac) complexes and (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazine Iridium(III) (abbreviation: Ir(mppr-Me)2(acac)), (acetyl arylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazinato)iridide Pyrazine skeletons such as Ir(III) (abbreviation: Ir(mppr-iPr)2(acac)) Organometallic iridium complexes and tris(2-phenylpyridinato-N,C 2’ ) Iridium(III) (abbreviation: Ir(ppy)3), bis(2-phenylpyridinato-N ,C 2’ ) Iridium(III) acetylacetonate (abbreviation: Ir(ppy)2(ac ac)), bis(benzo[h]quinolinato)iridium(III) acetylacetonate (abbreviation: Ir(bzq)2(acac)), tris(benzo[h]quinolinato)iridium Ir(III) (abbreviation: Ir(bzq)3), tris(2-phenylquinolinato-N,C 2 ’ ) Iridium(III) (abbreviation: Ir(pq)3), bis(2-phenylquinolinato- N,C 2’ ) Iridium(III) acetylacetonate (abbreviation: Ir(pq)2(ac Organometallic iridium complexes with pyridine skeletons such as bis(2,4-difluoromethyl) Phenyl-1,3-oxazolato-N,C 2’ ) Iridium(III) acetylacetoner Ir(dpo)2(acac)), bis{2-[4'-(perfluorophenyl) (phenyl)pyridinato-N,C 2’}Iridium(III) acetylacetonate( Abbreviation: Ir(p-PF-ph)2(acac)), bis(2-phenylbenzothiazol- -N,C 2’) Iridium(III) acetylacetonate (abbreviation: Ir(bt)2(a In addition to organometallic iridium complexes such as tris(acetylacetonato)(monophenyl) Anthroline) terbium(III) (abbreviation: Tb(acac)3(Phen)) Among the above, organometallic iridium complexes having a pyrimidine skeleton are Dium complexes are particularly preferred because they are remarkably excellent in reliability and luminous efficiency.

[0202] 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.

[0203] Among the above-mentioned iridium complexes, organic gold complexes having a pyrimidine skeleton or a pyrazine skeleton are also suitable. In iridium complexes, the ligands have high electron-accepting properties, and the LUMO level tends to be low. This is suitable for one aspect of the present invention. Compounds with electron-withdrawing substituents such as iridium complexes also have LUMO levels This is preferable because the

[0204] 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."

[0205] <Host Material 133> The host material 133 has a HOMO level lower than that of the host material 132. and the host material has a LUMO level higher than the LUMO level of the guest material 131. It is preferable to select the material 133, the host material 132, and the guest material 131. As a result, a light-emitting element having high luminous efficiency and driven at a low voltage can be obtained. As the material 133, the materials exemplified as the host material 132 may be used.

[0206] In addition, as the host material 133, a material having a higher electron transporting property than a hole transporting property may be used. Can be done 1 x 10 -6 cm 2 It is preferable that the material has an electron mobility of 1 / Vs or more. Nitrogen-containing heteroaromatic compounds are examples of materials that readily accept electrons (materials with electron transport properties). Compounds with π-electron-deficient heteroaromatic ring skeletons, such as zinc and aluminum metals Complexes, etc. can be used. Specifically, quinoline ligands, benzoquinoline ligands, Metal complexes with oxazole or thiazole ligands, and oxadiazole Derivatives, triazole derivatives, benzimidazole derivatives, quinoxaline derivatives, dibenzo quinoxaline derivatives, phenanthroline derivatives, pyridine derivatives, bipyridine derivatives, Examples of the compounds include pyrimidine derivatives and triazine derivatives.

[0207] 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, and pyridine skeleton are also Heterocyclic compounds having at least one diamine skeleton are preferred because they are stable and reliable. Furthermore, heterocyclic compounds having such skeletons have high electron transport properties and contribute to reducing driving voltage. In addition, poly(2,5-pyridinediyl) (abbreviation: PPy), poly[(9,9-dihexyl) PF -Py), poly[(9,9-dioctylfluorene-2,7-diyl)-co-(2,2 '-bipyridine-6,6'-diyl)] (abbreviation: PF-BPy) The substances mentioned here are mainly 1×10 -6 cm 2 / Vs or more electron transfer In addition, if a substance has a higher electron transporting property than a hole transporting property, The following substances may also be used.

[0208] As the host material 133, the following hole transporting materials can be used.

[0209] 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.

[0210] 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. .

[0211] 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:

[0212] 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.

[0213] 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.

[0214] 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.

[0215] 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.

[0216] 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 compounds mentioned above, those having a pyrrole skeleton, a furan skeleton, a thiophene skeleton, and A compound having at least one aromatic amine skeleton is preferred because it is stable and has good reliability. In addition, the compound having this skeleton has a high hole transporting property, which contributes to a reduction in driving voltage.

[0217] 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 material having electron transport properties 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.

[0218] 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.

[0219] 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.).

[0220] ≪Quantum dots≫ Quantum dots are semiconductor nanocrystals with sizes ranging from several nanometers to several tens of nanometers, and are 1×10 3 From pieces 1×10 6 Quantum dots are composed of about 100 atoms. Therefore, even if quantum dots are made of the same material, the emission wavelengths vary depending on the size. Therefore, by changing the size of the quantum dots used, light emission can be easily The wavelength can be changed.

[0221] In addition, quantum dots have a narrow peak width in the emission spectrum, which allows for emission of light with good color purity. Furthermore, the theoretical internal quantum efficiency of quantum dots is said to be 100%. This accounts for much more than 25% of organic compounds that exhibit fluorescence, and 15% of organic compounds that exhibit phosphorescence. Therefore, by using quantum dots as a light-emitting material, It is possible to obtain a light-emitting device with high luminous efficiency. Since the inherent stability of the material is also excellent, it is possible to obtain a light-emitting device that is favorable in terms of lifespan. can.

[0222] The materials that make up quantum dots include elements from Group 14, Group 15, Group 16, and complexes. Compounds consisting of several Group 14 elements, and compounds consisting of elements belonging to Groups 4 to 14 and Group 16 elements Compounds, compounds of Group 2 elements and Group 16 elements, compounds of Group 13 elements and Group 15 elements , compounds of Group 13 elements and Group 17 elements, compounds of Group 14 elements and Group 15 elements, Compounds of group 11 elements and group 17 elements, iron oxides, titanium oxides, chalcogenide spines Examples include various semiconductor clusters.

[0223] Specifically, cadmium selenide, cadmium sulfide, cadmium telluride, and sulfur selenide Lead, zinc oxide, zinc sulfide, zinc telluride, mercury sulfide, mercury selenide, mercury telluride, arsenide Indium, indium phosphide, gallium arsenide, gallium phosphide, indium nitride, nitride Gallium, indium antimonide, gallium antimonide, aluminum phosphide, arsenide Aluminum, aluminum antimonide, lead selenide, lead telluride, lead sulfide, selenide Indium, indium telluride, indium sulfide, gallium selenide, arsenic sulfide, selenium arsenic nitride, arsenic telluride, antimony sulfide, antimony selenide, antimony telluride, Bismuth sulfide, bismuth selenide, bismuth telluride, silicon, silicon carbide, germanium Aluminum, tin, selenium, tellurium, boron, carbon, phosphorus, boron nitride, boron phosphide, boron arsenide , aluminum nitride, aluminum sulfide, barium sulfide, barium selenide, barium telluride Sulfur dioxide, calcium sulfide, calcium selenide, calcium telluride, beryllium sulfide, Beryllium selenide, beryllium telluride, magnesium sulfide, magnesium selenide, Germanium sulfide, germanium selenide, germanium telluride, tin sulfide, tin selenide , tin telluride, lead oxide, copper fluoride, copper chloride, copper bromide, copper iodide, copper oxide, copper selenide, acid Nickel oxide, cobalt oxide, cobalt sulfide, iron oxide, iron sulfide, manganese oxide, molyb sulfide vanadium oxide, tungsten oxide, tantalum oxide, titanium oxide, zirconium oxide Aluminum, silicon nitride, germanium nitride, aluminum oxide, barium titanate, selenium and zinc Compounds of lead and cadmium, compounds of indium, arsenic and phosphorus, compounds of cadmium, selenium and sulfur Compounds of cadmium, selenium and tellurium, compounds of indium, gallium and arsenic , compounds of indium, gallium and selenium, compounds of indium, selenium and sulfur, compounds of copper and indium Examples of the compounds include indium and sulfur compounds, and combinations thereof. In addition, alloy quantum dots, whose compositions are expressed in any ratio, may be used. For example, alloy quantum dots of cadmium, selenium, and sulfur can be obtained by changing the ratio of the elements. This is one of the effective methods to obtain blue light emission, because the emission wavelength can be changed by It is one.

[0224] Quantum dot structures include core type, core-shell type, and core-multishell type. Either of these can be used, but it is also possible to cover the core with another inorganic compound with a wider band gap. By forming a shell of material, defects and dangling bonds on the nanocrystal surface can be eliminated. This significantly improves the quantum efficiency of light emission, It is preferable to use core-shell or core-multishell quantum dots. Examples of materials include zinc sulfide and zinc oxide.

[0225] In addition, quantum dots have a high proportion of surface atoms, making them highly reactive and prone to aggregation. Therefore, a protective agent or a protective group is attached to the surface of the quantum dots. It is preferable that the protecting agent is attached or the protecting group is provided. It can prevent aggregation and increase solubility in solvents. It can also reduce reactivity and improve electrical conductivity. It is also possible to improve stability. Examples of protecting agents (or protecting groups) include polio Polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene Polyoxyethylene alkyl ethers such as ethylene oleyl ether, tripropyl phosphite phosphine, tributylphosphine, trihexylphosphine, trioctylphosphine, etc. Trialkylphosphines, polyoxyethylene n-octylphenyl ether, polyoxyethylene Polyoxyethylene alkylphenyl ethers such as oxyethylene n-nonylphenyl ether esters, tri(n-hexyl)amine, tri(n-octyl)amine, tri(n-decyl)amine ) Tertiary amines such as amine, tripropylphosphine oxide, tributylphosphine oxide, trihexylphosphine oxide, trioctylphosphine oxide, tridecylphosphine oxide Organic phosphorus compounds such as silylphosphine oxide, polyethylene glycol dilaurate, polyethylene glycol diesters such as polyethylene glycol distearate, Organic nitrogen compounds such as nitrogen-containing aromatic compounds such as pyridine, lutidine, collidine, and quinolines , hexylamine, octylamine, decylamine, dodecylamine, tetradecylamine aminoalkanes such as dibutylsulfone, hexadecylamine, and octadecylamine; dialkyl sulfides such as dimethyl sulfoxide and dibutyl sulfoxide; organic sulfur compounds such as alkyl sulfoxides, sulfur-containing aromatic compounds such as thiophene, palmitoyl Higher fatty acids such as acetic acid, stearic acid, and oleic acid, alcohols, sorbitan fatty acid esters esters, fatty acid modified polyesters, tertiary amine modified polyurethanes, polyethylene terephthalate Examples include amines.

[0226] As quantum dots become smaller, their band gaps become larger, so they can emit the desired wavelengths. The size of the crystal is adjusted accordingly to obtain long-range light. As a result, the emission of quantum dots shifts to the blue side, i.e., to the higher energy side. By changing the size of the filter, wavelengths in the ultraviolet, visible, and infrared regions of the spectrum can be obtained. The size (diameter) of quantum dots can be adjusted over a range of wavelengths. The range of 0.5 nm to 20 nm, preferably 1 nm to 10 nm, is usually used. The narrower the size distribution of quantum dots, the narrower the emission spectrum. The quantum dots can be formed in any shape, and can have excellent color purity. The quantum dots may be spherical, rod-shaped, disc-shaped, or have other shapes. Since the rods have the function of emitting directional light, quantum rods can be used as light-emitting materials. This makes it possible to obtain a light emitting device with better external quantum efficiency.

[0227] In most cases, organic EL devices are made by dispersing a light-emitting material in a host material. The host material is more than just a light-emitting material; it also has a high luminous efficiency. The material must have a singlet or triplet excited energy level. In particular, when a blue phosphorescent material is used as the light-emitting material, further triplet excitation is required. A host material with an energy level and excellent lifetime is required, and its development is Here, quantum dots emit light by themselves without using a host material. Even if a layer is formed, the luminous efficiency can be maintained, which is also preferable from the viewpoint of life. When the light-emitting layer is formed only with quantum dots, The polymer preferably has a core-shell structure (including a core-multishell structure).

[0228] When quantum dots are used as the light-emitting material of the light-emitting layer, the thickness of the light-emitting layer is 3 nm to 100 nm. m, preferably 10 nm to 100 nm, and the content of quantum dots in the light-emitting layer is 1 to 1 However, it is preferable to form the light-emitting layer only from quantum dots. When forming a light-emitting layer in which the quantum dots are dispersed in a host as a light-emitting material, the host material Alternatively, the host material and the quantum dots are dissolved or dispersed in a suitable liquid medium. Disperse and apply wet processes (spin coating, casting, die coating, blade coating) Coating method, roll coating method, inkjet method, printing method, spray coating method, curtain coating The phosphorescent material may be formed by a method such as the ion beam splitting method or the Langmuir-Blodgett method. For the light-emitting layer using the above, in addition to the wet process, a vacuum deposition method can also be suitably used. This can be done.

[0229] Examples of liquid media used in wet processes include methyl ethyl ketone, cyclohexane, and the like. Ketones such as xanone, fatty acid esters such as ethyl acetate, halogens such as dichlorobenzene aromatic hydrocarbons, toluene, xylene, mesitylene, cyclohexylbenzene, etc. Hydrocarbons, aliphatic hydrocarbons such as cyclohexane, decalin, and dodecane, dimethylformamide Organic solvents such as dimethyl amide (DMF) and dimethyl sulfoxide (DMSO) can be used. Cut.

[0230] <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).

[0231] 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.

[0232] 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.

[0233] <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).

[0234] Also, 1×10 -6 cm 2 It is preferable that the material has a hole mobility of 1 / Vs or more. However, other materials 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.

[0235] ≪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. Specifically, The quinoline ligand, benzoquinoline ligand, and oxazole ligand listed as electron transport materials that can be used ligands, or metal complexes with thiazole ligands, oxadiazole derivatives, triazole azole derivatives, benzimidazole derivatives, quinoxaline derivatives, dibenzoquinoxaline Derivatives, phenanthroline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives and triazine derivatives. -6 cm 2 / Vs or more electron transfer It is preferable that the material has a higher electron transporting property than the hole transporting property. If desired, a material other than the above may be used for the electron transport layer. The layer may be a single layer or may be a laminate of two or more layers made of the above-mentioned materials.

[0236] Furthermore, a layer for controlling the movement of electron carriers may be provided between the electron transport layer 118 and the light emitting layer. This is because a small amount of a substance with high electron trapping properties is added to a material with high electron transport properties as described above. It is a doped layer that suppresses the movement of electron carriers, thereby improving the carrier balance. This structure prevents electrons from penetrating the light-emitting layer. This is highly effective in suppressing problems that arise from this (for example, a reduction in the lifespan of the element).

[0237] Alternatively, n-type compound semiconductors may be used, such as titanium oxide, zinc oxide, and silicon oxide. element, tin oxide, tungsten oxide, tantalum oxide, barium titanate, barium zirconate , zirconium oxide, hafnium oxide, aluminum oxide, yttrium oxide, silicate Oxides such as zinc, nitrides such as silicon nitride, cadmium sulfide, zinc selenide and zinc sulfide, etc. can also be used.

[0238] ≪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. Lithium fluoride, sodium fluoride, cesium fluoride, calcium fluoride, lithium Use of alkali metals, alkaline earth metals, or their compounds such as oxides Also, rare earth metal compounds such as erbium fluoride can be used. Furthermore, an electride may be used for the electron injection layer 119. Examples of the electride include For example, a substance in which a high concentration of electrons is added to a mixed oxide of calcium and aluminum can be mentioned. In addition, the electron injection layer 119 may be formed using a material that can be used in the electron transport layer 118. good.

[0239] 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.

[0240] 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.

[0241] <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.

[0242] 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.

[0243] 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.

[0244] 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.

[0245] 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 1×10 5 Ω·cm or less, more preferably 1×10 4 Ω cm The following is the result.

[0246] 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.

[0247] 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.

[0248] 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.

[0249] 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.

[0250] 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. O2 can resonate light of a desired wavelength from each light-emitting layer and intensify the light of the desired wavelength. This is preferable because it has the function of adjusting the optical distance so that the optical path can be adjusted.

[0251] 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.

[0252] <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.

[0253] 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.

[0254] For example, in the present invention, a light emitting element can be formed using various substrates. The type of substrate is not limited to a specific one. An example of the substrate is a semiconductor substrate. Substrates (e.g., single crystal substrates or silicon substrates), SOI substrates, glass substrates, quartz substrates, plus Includes tungsten substrate, metal substrate, stainless steel substrate, and stainless steel foil. Substrate, tungsten substrate, substrate with tungsten foil, flexible substrate, bonding Examples of substrates include films, paper containing fibrous materials, and base films. barium borosilicate glass, aluminoborosilicate glass, or soda lime glass Examples of flexible substrates, laminated films, base films, etc. are as follows: For example, polyethylene terephthalate (PET), polyethylene naphtha Phthalate (PEN), Polyethersulfone (PES), Polytetrafluoroethylene Plastics such as PTFE are also available. Examples include polypropylene, polyester, and polyvinyl fluoride. Examples include polyamide, polyimide, and polyvinyl chloride. Examples include aramid, epoxy, inorganic vapor deposition film, and paper.

[0255] 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.

[0256] 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.

[0257] 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.

[0258] 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 lower than the LUMO level of the host material, and the L The energy difference between the UMO level and the HOMO level is Although an example in which the energy difference between the positions is larger than that of the positions is shown, one embodiment of the present invention is not limited to this. In some cases or depending on the situation, in one aspect of the present invention, for example, the guest material The material may not have the function of converting triplet excitation energy into luminescence. The LUMO level of the dopant material does not have to be lower than the LUMO level of the host material. The energy difference between the LUMO level and the HOMO level of the guest material is The energy difference between the HOMO level and the HOMO level may not be larger than the energy difference between the HOMO level and the HOMO level. In one embodiment, the host material has a singlet excited energy level and a triplet excited energy level. Although an example in which the difference is greater than 0 eV and not more than 0.2 eV has been shown, one embodiment of the present invention is In some cases or depending on the situation, in one aspect of the present invention, For example, the host material has a difference between the singlet and triplet excited energy levels of 0. It may be greater than 2 eV.

[0259] As described above, the structure shown in this embodiment mode can be used in appropriate combination with other embodiment modes. Cut.

[0260] (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 The light emitting mechanism of the light emitting element will be described below with reference to FIGS. 5(A) and 6(A), the parts having the same functions as those shown in FIG. 1(A) are denoted by the reference numerals. In some cases, the same hatch pattern is used and the reference numeral is omitted. The same reference numerals are used to denote the same parts, and detailed explanations thereof may be omitted.

[0261] <Configuration example 1 of light-emitting element> FIG. 5A is a schematic cross-sectional view of the light emitting element 250. FIG.

[0262] 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 an EL layer 10 1 and the light-emitting element 150 shown in FIG. The light emitting element 152 has one light emitting unit, and the light emitting element 250 has multiple light emitting units. In the light-emitting element 250, the electrode 101 functions as an anode. The following description will be given assuming that the electrode 102 functions as a cathode. However, the opposite is also acceptable.

[0263] 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, it is preferable to use the EL layer 100 in the light-emitting unit 106. It's nice.

[0264] The light emitting element 250 has a light emitting layer 120 and a light emitting layer 170. In addition to the light-emitting layer 170, 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 120. 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.

[0265] 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.

[0266] 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 material 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, the anode side of the light-emitting unit is in contact with the charge generating layer 115. In this case, the charge generation layer 115 also serves as a hole injection layer or a hole transport layer for the light-emitting unit. Therefore, the light-emitting unit does not need to have a hole injection layer or a hole transport layer. Alternatively, when the cathode side surface of the light-emitting unit is in contact with the charge generating layer 115, The charge generation layer 115 also serves as an electron injection layer or an electron transport layer for the light-emitting unit. Therefore, the light-emitting unit does not have an electron injection layer or an electron transport layer. is also good.

[0267] 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.

[0268] 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.

[0269] 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.

[0270] 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.

[0271] 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. .

[0272] 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.

[0273] The light-emitting layer 170 of the light-emitting unit 106 is the same as the light-emitting layer 13 shown in the first embodiment. 0 or light-emitting layer 135. By doing so, the light-emitting element 250 has This is preferable as it becomes a light emitting element with high luminous efficiency.

[0274] Furthermore, the light-emitting layer 120 of the light-emitting unit 108 is formed by adding a guest The guest material 121 is a fluorescent material. , as explained below.

[0275] <Light Emitting Mechanism of Light Emitting Layer 120> The light emitting mechanism of the light emitting layer 120 will be explained below.

[0276] 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.

[0277] An exciton is a pair of carriers (electrons and holes). Therefore, the material in which the excitons are generated is in an excited state.

[0278] 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.

[0279] 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.

[0280] 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.

[0281] 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

[0282] As shown in Figure 5(C), triplet-triplet annihilation (TTA) Triplets generated by carrier recombination are generated by Excitons interact with each other, transferring excitation energy and exchanging spin angular momentum. As a result, the S1 level (S FH ) has an energy of A reaction occurs in which the host material 122 is converted into a singlet exciton (see Figure 5(C) TTA). The singlet excitation energy of FH from a lower energy guest material121 S1 level (S FG ) (see Route E5 in Figure 5(C)), and the guest A singlet excited state of the material 121 is formed, and the guest material 121 emits light.

[0283] 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.

[0284] Furthermore, 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 E6 in Figure 5(C)) and then used for TTA.

[0285] 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.

[0286] 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. When the guest material 121 is added, the weight ratio of the guest material 121 is preferably greater than 0 and equal to or less than 0.05. By doing so, the probability of carrier recombination in the guest material 121 can be reduced. In addition, the T level (T FH ) to the T1 level (T FG ) This can reduce the probability of energy transfer to

[0287] The host material 122 may be composed of a single compound or a plurality of compounds. It may be formed.

[0288] 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.

[0289] <Configuration example 2 of light-emitting element> FIG. 6A is a schematic cross-sectional view of the light emitting element 252. FIG.

[0290] The light emitting element 252 shown in FIG. 6A has a pair of electrodes, similar to the light emitting element 250 shown above. A plurality of light-emitting units (in FIG. 6(A), light-emitting elements) are disposed between the electrodes 101 and 102. The light unit 106 and the light-emitting unit 110 are included. At least one light-emitting unit is The light-emitting unit 106 and the light-emitting unit 110 have the same structure as the EL layer 100. may be of the same or different configurations.

[0291] In addition, in the light-emitting element 252 shown in FIG. 6(A), the light-emitting unit 106 and the light-emitting unit The light-emitting unit 106 and the light-emitting unit 110 are stacked together, and a charge generating layer is formed between the light-emitting unit 106 and the light-emitting unit 110. For example, the EL layer 100 is preferably used in the light-emitting unit 106. It's nice.

[0292] The light emitting element 252 also includes a light emitting layer 140 and a light emitting layer 170. In addition to the light-emitting layer 170, the knit 106 includes a hole injection layer 111, a hole transport layer 112, an electron transport layer The light-emitting unit 110 also includes a light-emitting layer 140. 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.

[0293] 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.

[0294] It is also preferable that the light-emitting layer of the light-emitting unit 110 contains a phosphorescent material. The light-emitting layer 140 of the unit 110 includes a phosphorescent material, and the light-emitting unit 106 includes a The light-emitting layer 170 has the configuration of the light-emitting layer 130 or the light-emitting layer 135 shown in the first embodiment. An example of the configuration of the light emitting element 252 in this case will be described below.

[0295] The light-emitting layer 140 of the light-emitting unit 110 is composed of a guest material 1 as shown in FIG. The host material 142 includes an organic compound 142_ The light-emitting layer 140 includes the guest material 141 and the organic compound 142_2. The following description will be given assuming that 1 is a phosphorescent material.

[0296] <Light Emitting Mechanism of Light Emitting Layer 140> Next, the light emitting mechanism of the light emitting layer 140 will be described below.

[0297] The organic compound 142_1 and the organic compound 142_2 contained in the light-emitting layer 140 form an exciplex. Form.

[0298] The combination of organic compound 142_1 and organic compound 142_2 forms an exciplex with each other. Any combination is acceptable as long as one of the compounds has a hole transporting property. It is more preferable that the other is a compound having electron transport properties.

[0299] The organic compound 142_1, the organic compound 142_2, and the guest material in the light-emitting layer 140 The correlation of the energy level with 141 is shown in Figure 6(C). The symbols and symbols are as follows: Guest (141): Guest material 141 (phosphorescent material) ·Host(142_1): Organic compound 142_1 (host material) ·Host(142_2): Organic compound 142_2 (host material) T PG : T1 level of guest material 141 (phosphorescent material) ·S PH1 : S1 level of organic compound 142_1 (host material) T PH1 :T1 level of organic compound 142_1 (host material) ·S PH2 : S1 level of organic compound 142_2 (host material) T PH2 :T1 level of organic compound 142_2 (host material) ·S PE : S1 level of the exciplex T PE :T1 level of exciplex

[0300] The organic compound 142_1 and the organic compound 142_2 form an exciplex, and the S 1 level (S PE ) and T1 level (T PE ) are adjacent energy levels (Figure 6( C) See route E7).

[0301] One of the organic compounds 142_1 and 142_2 receives a hole and the other receives an electron. Alternatively, when one of the two is excited, it quickly forms an exciplex. Therefore, the exciplex in the light-emitting layer 140 Most of the excited molecules exist as exciplexes. The excited energy levels of exciplexes (S PE Also is T PE ) is a host material (organic compound 142_1 and organic compound 142_2) that forms an exciplex. 42_2) S1 level (S PH1 and S PH2 ) and therefore has a lower excitation energy This allows the formation of an excited state in the host material 142. The driving voltage of the element can be reduced.

[0302] And the (S PE ) and (T PE ) and the energy of the guest material 141 (phosphorescent material) to the T1 level, and light emission is obtained (see routes E8 and E9 in Figure 6(C)). see).

[0303] In addition, the T1 level of the exciplex (T PE ) is the T1 level (T PG )twist By doing so, the singlet excitation energy and and triplet excitation energy to the S1 level (S PE ) and T1 level (T PE )mosquito The T1 level (T PG) can transfer energy to

[0304] In addition, in order to efficiently transfer excitation energy from the exciplex to the guest material 141, , the T1 level of the exciplex (T PE ) are each organic compound that forms an exciplex (organic compound 14 T1 levels (T PH1 and T PH2 ) or It is preferable that the organic compound 142_1 and the organic compound 142_2 are smaller than the organic compound 142_1. Compound 142_2) is less likely to quench the triplet excitation energy of the exciplex. Energy transfer from the exciplex to the guest material 141 occurs efficiently.

[0305] In addition, the organic compound 142_1 and the organic compound 142_2 efficiently form an exciplex. In order to achieve this, the HOMO level of one of the organic compounds 142_1 and 142_2 must be The HOMO level is higher than the other, and the LUMO level of one is higher than the LUMO level of the other. For example, the organic compound 142_1 has a hole transporting property, and the organic compound 142_2 has a hole transporting property. When the organic compound 142_1 has electron transport properties, the HOMO level of the organic compound 142_2 It is preferable that the LUMO level of the organic compound 142_1 is higher than the HOMO level of the organic compound 142_2. It is preferable that the LUMO level of the organic compound 142_2 is higher than that of the organic compound 142_3. When organic compound 142 has hole transporting properties and organic compound 142_1 has electron transporting properties, organic compound 1 The HOMO level of 42_2 is preferably higher than the HOMO level of the organic compound 142_1. , the LUMO level of organic compound 142_2 is higher than the LUMO level of organic compound 142_1. Specifically, it is preferable that the HOMO level of the organic compound 142_1 and the HOMO level of the organic compound 142_2 are The energy difference between the HOMO level of _2 is preferably 0.05 eV or more, and more preferably The electron transport potential is preferably 0.1 eV or more, and more preferably 0.2 eV or more. The energy difference between the LUMO level of organic compound 142_1 and the LUMO level of organic compound 142_2 is Preferably, it is 0.05 eV or more, more preferably 0.1 eV or more, and even more preferably Preferably, it is 0.2 eV or more.

[0306] In addition, the combination of organic compound 142_1 and organic compound 142_2 has hole transport properties. When a compound having electron transport properties is used in combination with a compound having electron transport properties, the mixing ratio Specifically, the carrier balance can be easily controlled by using a material having hole transport properties. The compound having electron transport properties:compound having electron transport properties is preferably in the range of 1:9 to 9:1 (weight ratio). In addition, by having this configuration, the carrier balance can be easily controlled. In addition, the carrier recombination region can be easily controlled.

[0307] In addition, the energy transfer between the host material 142 (exciplex) and the guest material 141 is The mechanism of the dynamic process is the Förster mechanism (dipole-dipole interaction) as in the first embodiment. This can be explained by two mechanisms: the electron exchange mechanism (electron exchange interaction) and the Dexter mechanism (electron exchange interaction). For details about the Förster mechanism and the Dexter mechanism, please refer to the first embodiment. .

[0308] Therefore, the singlet excited state of the host material (exciplex) is converted into the triplet excited state of the guest material 141. To facilitate the energy transfer to the excited state, the emission spectrum of the exciplex and the It is preferable that the absorption band of the photoresist material 141 overlaps with the absorption band appearing on the longest wavelength side (lowest energy side). This can increase the efficiency of generating the triplet excited state of the guest material 141. do.

[0309] By configuring the light-emitting layer 140 as described above, the guest material 141 (phosphorescent material ) can be efficiently obtained.

[0310] The above-described routes E7 to E9 are referred to as ExTET (Ex It is sometimes called plex-triplet energy transfer. In other words, the light-emitting layer 140 transfers the excitation energy from the exciplex to the guest material 141. In this case, it is not necessarily T PE From S PE High efficiency of reverse intersystem crossing is required No, S PE The quantum yield of light emission from the material does not need to be high, so a wide range of materials can be selected. It becomes possible.

[0311] Furthermore, the light emitted from the light-emitting layer 170 has a peak at a shorter wavelength than the light emitted from the light-emitting layer 140. It is preferable that the light-emitting element has a structure including a phosphorescent material that emits light of a short wavelength. Therefore, by using fluorescent light for short wavelengths, A light-emitting element with little deterioration in luminance can be provided.

[0312] In each of the above configurations, the light-emitting unit 106 and the light-emitting unit 108, or the light-emitting The emission colors of the guest materials used in the unit 106 and the light-emitting unit 110 include: The light-emitting units 106 and 108 may be the same or different. Alternatively, the light emitting unit 106 and the light emitting unit 110 may emit light of the same color. When the light-emitting element 250 and the light-emitting element 252 have a guest material having a light-emitting function, the light-emitting element 250 and the light-emitting element 252 can emit a small amount of current. The light-emitting unit 106 and the light-emitting unit 107 are preferably light-emitting elements that exhibit high light-emitting luminance. The unit 108, or the light emitting unit 106 and the light emitting unit 110, are of different colors. When a guest material having a function of emitting light is included, the light-emitting element 250 and the light-emitting element 252 In this case, the light-emitting layer 120 and the light-emitting layer 170 are preferably light-emitting elements that emit multicolor light. or either one or both of light-emitting layer 140 and light-emitting layer 170 By using a plurality of light-emitting materials with different emission wavelengths for both the light-emitting element 250 and the The emission spectrum exhibited by the light emitting element 252 is a composite of emission having different emission peaks. The resulting light has an emission spectrum with at least two maxima.

[0313] The above-mentioned structure is also suitable for obtaining white light emission. Alternatively, by making the light from the light-emitting layer 140 and the light-emitting layer 170 complementary in color, white light can be obtained. In particular, white light with high color rendering, or at least red and green light, can be obtained. It is preferable to select the guest material so that it emits light having blue and red.

[0314] In addition, at least one of the light-emitting layer 120, the light-emitting layer 140, and the light-emitting layer 170 is formed in a layered form. The light emitting element may be divided into layers, and each divided layer may contain a different light emitting material. At least one of the light-emitting layers 120, 140, and 170 is a multi-layer structure having two or more layers. For example, the first and second light-emitting layers may be arranged on the hole transport layer side. When the light-emitting layers are formed by laminating the first and second light-emitting layers in this order, a hole-transporting material is used as the host material of the first light-emitting layer. and a material having an electron transporting property is used as a host material for the second light-emitting layer. In this case, the light-emitting material contained in the first light-emitting layer and the second light-emitting layer is the same material. The materials may be different from each other, and may be materials that have the function of emitting light of the same color. The material may have a function of emitting light of different colors. By using a structure that has multiple luminescent materials with the function of emitting light, it is possible to emit light with three primary colors or four or more colors. It is also possible to obtain white light emission with high color rendering properties.

[0315] <Examples of materials that can be used for the light-emitting layer> Next, materials that can be used for the light-emitting layer 120, the light-emitting layer 140, and the light-emitting layer 170 will be described. The following explains the details.

[0316] <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).

[0317] 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: .

[0318] 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.

[0319] 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.

[0320] 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.

[0321] 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 .

[0322] <Materials that can be used for the light-emitting layer 140> In the light-emitting layer 140, the host material 142 is present in the largest amount by weight, and the guest material 141 The host material 142 (phosphorescent material) of the light-emitting layer 140 is dispersed in the host material 142. The T1 level of the organic compound 142_1 and the organic compound 142_2 is the T It is preferable that the level is higher than 1.

[0323] Organic compounds 142_1 include zinc and aluminum metal complexes, as well as oxadiazo derivatives, triazole derivatives, benzimidazole derivatives, quinoxaline derivatives, dibenzyl Dibenzoquinoxaline derivatives, dibenzothiophene derivatives, dibenzofuran derivatives, pyrimidin derivatives, triazine derivatives, pyridine derivatives, bipyridine derivatives, phenanthroline derivatives Other examples include aromatic amines and carbazole derivatives. Specifically, the electron transporting material and the hole transporting material shown in Embodiment 1 are used. It is possible.

[0324] The organic compound 142_2 is a compound that can form an exciplex with the organic compound 142_1. Specifically, the electron transport material and the hole transport material shown in Embodiment 1 are preferably used in combination. In this case, the organic compound 142_1 and the organic compound 142_2 can be used. The emission peak of the formed exciplex is the triplet MLCT( Metal to Ligand Charge Transfer (MLC) transition absorption band, Specifically, organic compound 142_1 and organic compound 142_2 are selected so that they overlap with the absorption band on the longest wavelength side. It is preferable to select the material 142_2 and the guest material 141 (phosphorescent material). As a result, a light-emitting element with dramatically improved luminous efficiency can be obtained. In addition, when a thermally activated delayed fluorescent material is used, the absorption band on the longest wavelength side is the absorption band of the singlet state. Preferably it is a band.

[0325] As the guest material 141 (phosphorescent material), an organic compound of iridium, rhodium, or platinum is used. 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 of the platinum complex include a platinum complex having a porphyrin ligand. The materials exemplified as the guest material 131 shown in 1 can be used.

[0326] The light-emitting material contained in the light-emitting layer 140 is a material capable of converting triplet excitation energy into light. The material capable of converting triplet excitation energy into luminescence is a phosphorescent material. In addition to the above, thermally activated delayed fluorescent materials are also included. In other words, it may be interpreted as a thermally activated delayed fluorescent material.

[0327] In addition, materials that exhibit thermally activated delayed fluorescence can be independently converted from triplet excited states by reverse intersystem crossing. The material may be capable of generating a doublet excited state, or may be an exciplex (or It may be made up of multiple materials that form a composite (also called an exciplex).

[0328] When the thermally activated delayed fluorescent material is composed of one kind of material, specifically, The thermally activated delayed fluorescent material shown in 1 can be used.

[0329] In addition, when a thermally activated delayed fluorescent material is used as a host material, two types of exciplexes are formed. It is preferable to use a combination of compounds of the same type. In this case, the compound forming the above-mentioned exciplex is The combination of compounds that readily accept electrons and compounds that readily accept holes is It is particularly preferred to use

[0330] <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. By using materials that can be used in the light-emitting device, a light-emitting device with high luminous efficiency can be created. It can be manufactured.

[0331] In addition, the light emission colors of the light emitting materials contained in the light emitting layers 120, 140, and 170 are There is no limitation, and they may be the same or different. The light emitted from each is mixed. For example, if the colors of the two lights are complementary to each other, The element can provide white light. The emission peak wavelength of the luminescent material contained in the luminescent layer 170 is shorter than that of the luminescent material contained in the luminescent layer 170. It is preferable that:

[0332] The light-emitting units 106, 108, 110, and the charge generating The layer 115 can be formed by a deposition method (including a vacuum deposition method), an inkjet method, a coating method, a gravure printing method, etc. It can be formed by the method described above.

[0333] The structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. You can be there.

[0334] (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.

[0335] <Configuration example 1 of light-emitting element> 7(A) and 7(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.

[0336] The light emitting element 260a and the light emitting element 260b shown in FIGS. 7A and 7B 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. .

[0337] 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.

[0338] 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 .

[0339] 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.

[0340] 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 made of the same material as the conductive layer 101a. When the electrode 101 is sandwiched between conductive materials, the etching step in the process of forming the electrode 101 This is preferable because it facilitates pattern formation by the method.

[0341] 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.

[0342] 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.

[0343] In FIGS. 7(A) and 7(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.

[0344] 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.

[0345] 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.

[0346] 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 containing more oxygen than silicon dioxide. It refers to a film with a high nitrogen content, preferably 55 atomic % to 65 atomic % of nitrogen and 100 atomic % of oxygen. 1 atomic % to 20 atomic %; silicon is 25 atomic % to 35 atomic %; hydrogen is 0.1 This refers to a substance contained in a concentration range of 10 atomic % or more.

[0347] 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.

[0348] 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.

[0349] 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.

[0350] 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.

[0351] 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.

[0352] 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.

[0353] <Configuration example 2 of light-emitting element> Next, regarding a configuration example different from that of the light-emitting element shown in FIGS. 7(A) and 7(B), FIGS. 8(A) and 8(B) are shown. The following description will be given using this.

[0354] 8(A) and 8(B) are cross-sectional views showing a light-emitting element of one embodiment of the present invention. 7(A) and (B), the same symbols are used for the parts having the same functions as those shown in FIG. 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.

[0355] 8A and 8B 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. 8(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.

[0356] 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 .

[0357] 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.

[0358] The light emitting element 262a shown in FIG. 8(A) and the light emitting element 262b shown in FIG. 8(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.

[0359] 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.

[0360] 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.

[0361] 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.

[0362] 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.

[0363] 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.

[0364] In FIG. 8(A) and (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.

[0365] 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.

[0366] 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.

[0367] 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.

[0368] The substrate 200 and the substrate 220 having the optical element are configured as in the first embodiment. Please take this into consideration.

[0369] Furthermore, the light emitting element 262a and the light emitting element 262b have a microcavity structure. .

[0370] <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.

[0371] 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. In the region, at least one of the hole injection layer 111 and the hole transport layer 112, or the electron injection By varying the thickness of at least one of the layer 119 and the electron transport layer 118, the light emitting The light emitted from layer 170 and light-emitting layer 190 may be enhanced.

[0372] 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 B represent 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).

[0373] 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

[0374] 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.

[0375] 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.

[0376] The light emitting element 262a shown in FIG. 8(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.

[0377] Furthermore, the light emitting element 262b shown in FIG. 8B is a bottom emission type light emitting element, and therefore has no 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.

[0378] 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.

[0379] 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.

[0380] 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.

[0381] 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.

[0382] 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.

[0383] 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.

[0384] <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. 9 and 10. Here, a method for manufacturing the light-emitting element 262a shown in FIG. do.

[0385] 9 and 10 are cross-sectional views illustrating a method for manufacturing a light-emitting element according to one embodiment of the present invention. do.

[0386] The method for fabricating the light emitting element 262a described below includes seven steps, namely, first to seventh steps. do.

[0387] <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. 9(A)).

[0388] 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.

[0389] 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.

[0390] <<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. 9(B)).

[0391] 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.

[0392] 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.

[0393] <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 9(C)).

[0394] 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.

[0395] 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.

[0396] <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 (FIG. 10(A) reference).

[0397] 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.

[0398] 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.

[0399] 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.

[0400] 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

[0401] <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. 118, an electron injection layer 119, and an electrode 102 are formed (see FIG. 10(B)). .

[0402] 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.

[0403] 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. .

[0404] 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.

[0405] 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.

[0406] 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.

[0407] <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. 10(C)).

[0408] 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.

[0409] <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).

[0410] Through the above steps, the light-emitting element 262a shown in FIG. 8(A) can be formed.

[0411] 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.

[0412] (Fourth embodiment) In this embodiment, a display device of one embodiment of the present invention will be described with reference to FIGS. Reveal.

[0413] <Display device configuration example 1> 11(A) is a top view showing the display device 600, and FIG. 11(B) is a diagram showing the display device 600 shown in FIG. 11(A) 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.

[0414] 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.

[0415] 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.

[0416] 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.

[0417] 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.

[0418] 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.

[0419] 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).

[0420] 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.

[0421] 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).

[0422] 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.

[0423] 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.

[0424] 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.

[0425] 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.

[0426] 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.

[0427] <Configuration example 2 of the display device> Next, another example of the display device will be described with reference to FIGS. 12(A), 12(B) and 13. 12A, 12B, and 13 are cross-sectional views of display devices according to embodiments of the present invention. .

[0428] FIG. 12(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. .

[0429] In addition, in FIG. 12(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. 12(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.

[0430] In FIG. 12B, 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 .

[0431] In FIG. 13, 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.

[0432] 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).

[0433] <Configuration example 3 of the display device> An example of a cross-sectional view of a top-emission type display device is shown in FIGS. 14(A) and 14(B). 12(A) and 12(B) are cross-sectional views illustrating a display device of one embodiment of the present invention. 13.) and the driving circuit section 1041, the peripheral section 1042, etc. shown in FIG. 13 are omitted in the illustration.

[0434] 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.

[0435] 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 14(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.

[0436] In the top emission structure shown in FIG. 14(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.

[0437] In addition, in FIG. 14(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. 14(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.

[0438] <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) 15 to 17 show the lower electrodes 1024R, 1024G, 1024B, 15(A), (B) and 16 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) 17(A) and 17(B) show a structure in which light is extracted to the sealing substrate 1031 side ( It is a top-emission display device.

[0439] FIG. 15(A) shows the optical element (colored layer 1034R, colored layer 1034G, colored layer 1034B 15 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. 16 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.

[0440] 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 color layer 1034Y has a function of transmitting light, the light transmitted through the color 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.

[0441] In the top emission type display device shown in FIG. 17, 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.

[0442] 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.

[0443] In addition, in FIG. 17(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. 17(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. 17(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.

[0444] <Display Device Configuration Example 5> Next, a display device according to another embodiment of the present invention is shown in FIG. 18. FIG. 18 shows the same display device as FIG. 11(A 18 is a cross-sectional view taken along dashed lines AB and CD. 11(B) are assigned the same reference numerals as those in FIG. 11(B), and their details are Detailed explanations will be omitted.

[0445] The display device 600 shown in FIG. 18 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.

[0446] 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.

[0447] <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.

[0448] The display device shown in FIG. 19(A)(B) has a structure in which light is extracted to the sealing substrate 1031 side (transistor). 19A shows a display device of a light-emitting layer 1028R, a light-emitting layer 1028R, and a light-emitting layer 1028R. 19B 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.

[0449] 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.

[0450] The display devices shown in FIGS. 19(A) and 19(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.

[0451] 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.

[0452] 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.

[0453] 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.

[0454] Note that the configuration shown in this embodiment may be appropriately combined with other embodiments or other configurations in this embodiment. Combinations are possible.

[0455] (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 given with reference to FIG.

[0456] Note that FIG. 20A is a block diagram illustrating a display device of one embodiment of the present invention, and FIG. 1B is a circuit diagram illustrating a pixel circuit included in a display device of one embodiment of the present invention.

[0457] <Explanation about the display device> The display device shown in FIG. 20A has a region having pixels of a display element (hereinafter referred to as a pixel portion 802). ) and a circuit section ( hereinafter referred to as a drive circuit section 804), and a circuit having a function of protecting the element (hereinafter referred to as a protection circuit 80 6) and a terminal portion 807. Note that the protection circuit 806 is not provided in the configuration. That's fine.

[0458] A part or the whole of the driver circuit portion 804 is formed on the same substrate as the pixel portion 802. This makes it possible to reduce the number of parts and terminals. When a part or all of the driving circuit is not formed on the same substrate as the pixel portion 802, A part or the whole of the path portion 804 is COG or TAB (Tape Automated Bearing). It can be implemented by

[0459] The pixel section 802 is arranged in X rows (X is a natural number of 2 or more) and Y columns (Y is a natural number of 2 or more). The display device has a circuit for driving a plurality of display elements (hereinafter referred to as pixel circuit 801), The path portion 804 is a circuit for outputting a signal (scanning signal) for selecting a pixel (hereinafter referred to as a scanning line driving circuit 804a), for supplying signals (data signals) for driving the display elements of the pixels. The signal line driver circuit 804b includes a driver circuit such as the circuit (hereinafter referred to as a signal line driver circuit 804b).

[0460] The scanning line driver circuit 804a includes a shift register and the like. A signal for driving the shift register is inputted through the terminal portion 807, and a signal is outputted. For example, a start pulse signal, a clock signal, etc. are input to the scanning line driver circuit 804a. The scanning line driving circuit 804a is connected to the wiring to which the scanning signal is applied (hereinafter referred to as the wiring). The scanning lines GL_1 to GL_X are connected to the gate electrode GL_1. A plurality of driving circuits 804a are provided, and the scanning lines GL_1 to GL_3 are driven by the plurality of scanning line driving circuits 804a. Alternatively, the scanning line driving circuit 804a may control the GL_X by dividing it. However, the present invention is not limited to this, and the scanning line driving circuit 80 4a may also provide other signals.

[0461] The signal line driver circuit 804b includes a shift register and the like. Through the terminal portion 807, signals for driving the shift register as well as the source of the data signal are transmitted. The signal line driver circuit 804b receives the image signal and drives the pixel circuit The signal line driver circuit 804b has a function of generating a data signal to be written to the signal line driver circuit 804b. A data signal is generated in accordance with a pulse signal obtained by inputting a start pulse, a clock signal, etc. The signal line driver circuit 804b has a function of controlling the output of a signal. The data lines DL_1 to DL_Y are connected to the data lines DL_2 through DL_Y. Alternatively, the signal line driver circuit 804b may have a function of supplying an initialization signal. However, the present invention is not limited to this, and the signal line driver circuit 804b may also supply other signals. It is possible.

[0462] The signal line driver circuit 804b is configured using, for example, a plurality of analog switches. The signal line driver circuit 804b sequentially turns on a plurality of analog switches, The image signal can be time-divided and output as a data signal. The signal line driver circuit 804b may be configured using the same.

[0463] Each of the plurality of pixel circuits 801 is connected to one of the plurality of scanning lines GL to which a scanning signal is applied. A pulse signal is input via the data line DL, and a data signal is given via one of the data lines DL. Each of the pixel circuits 801 receives a data signal via a scanning line driving circuit. 804a controls the writing and holding of data of the data signal. The second pixel circuit 801 is connected to the scanning line driving circuit GL_m (m is a natural number equal to or less than X) via the scanning line GL_m. A pulse signal is input from 804a, and the potential of the data line DL_n ( A data signal is input from the signal line driver circuit 804b via the signal line driver circuit 804b (n is a natural number equal to or less than Y).

[0464] The protection circuit 806 shown in FIG. 20A is, for example, a protection circuit including a scanning line driver circuit 804a and a pixel circuit 8 01. Alternatively, the protection circuit 806 is connected to the scanning line GL, which is the wiring between the signal line driver The data line DL is connected between the circuit 804b and the pixel circuit 801. The protection circuit 806 can be connected to the wiring between the scanning line driving circuit 804a and the terminal portion 807. Alternatively, the protection circuit 806 may be formed on the wiring between the signal line driver circuit 804b and the terminal portion 807. The terminal portion 807 can be connected to a power supply and a line from an external circuit to the display device. This refers to the part where terminals for inputting control signals and image signals are provided.

[0465] When a potential outside a certain range is applied to the wiring to which the protection circuit 806 is connected, the protection circuit 806 This is a circuit that brings one wire into electrical continuity with another wire.

[0466] As shown in FIG. 20A, a pixel section 802 and a driver circuit section 804 are provided with a protection circuit 80. 6. By connecting the This can improve the display device's resistance to overcurrents caused by electrostatic discharge (ESD) and other factors. However, the configuration of the protection circuit 806 is not limited to this. For example, or a configuration in which the protection circuit 806 is connected to the signal line driver circuit 804b. Alternatively, a configuration in which a protection circuit 806 is connected to the terminal portion 807 may be used. It can also be made into a

[0467] In FIG. 20A, the scanning line driver circuit 804a and the signal line driver circuit 804b Therefore, although an example in which the driver circuit portion 804 is formed is shown, the present invention is not limited to this configuration. For example, only the scanning line driver circuit 804a is formed, and a signal line driver circuit prepared separately is formed. A substrate (for example, a drive circuit board formed of a single crystal semiconductor film or a polycrystalline semiconductor film) is mounted. It may also be configured as follows.

[0468] <Pixel circuit configuration example> The plurality of pixel circuits 801 shown in FIG. 20(A) may have the configuration shown in FIG. 20(B), for example. It is possible.

[0469] The pixel circuit 801 shown in FIG. 20B includes transistors 852 and 854 and a capacitor 86 2 and a light-emitting element 872.

[0470] One of the source electrode and the drain electrode of the transistor 852 is supplied with a data signal. The gate of the transistor 852 is electrically connected to the wiring (data line DL_n). The electrodes are electrically connected to wiring (scanning lines GL_m) to which gate signals are applied.

[0471] The transistor 852 has a function of controlling writing of data signals.

[0472] One of the pair of electrodes of the capacitor 862 is connected to a wiring to which a potential is applied (hereinafter, a potential supply line VL _a), and the other is electrically connected to the source electrode and drain electrode of transistor 852. The second electrode is electrically connected to the other of the first and second electrodes.

[0473] The capacitor 862 functions as a storage capacitor for holding written data.

[0474] One of the source electrode and the drain electrode of the transistor 854 is connected to the potential supply line VL_a. Furthermore, the gate electrode of transistor 854 is electrically connected to the It is electrically connected to the other of the source electrode and the drain electrode.

[0475] One of the anode and cathode of the light emitting element 872 is electrically connected to the potential supply line VL_b. The other is electrically connected to the other of the source electrode and drain electrode of the transistor 854. will be done.

[0476] The light-emitting element 872 may be any of the light-emitting elements described in any of Embodiments 1 to 3. can be done.

[0477] A high power supply potential VDD is applied to one of the potential supply lines VL_a and VL_b. and the other is supplied with a low power supply potential VSS.

[0478] In a display device having the pixel circuit 801 of FIG. 20(B), for example, The scanning line driving circuit 804a sequentially selects the pixel circuits 801 in each row, and turns on the transistors 852. The data signal is written by turning it on.

[0479] The pixel circuit 801 in which data has been written is turned off by turning off the transistor 852. Furthermore, the potential of the transistor 854 changes depending on the potential of the written data signal. The amount of current flowing between the source electrode and the drain electrode is controlled, and the light emitting element 872 The light is emitted at a brightness that corresponds to the flow rate. By repeating this process row by row, an image can be displayed.

[0480] In addition, the pixel circuit has a function to correct the influence of fluctuations in the threshold voltage of the transistor, etc. 21(A) and 21(B) and 22(A) and 22(B) show examples of pixel circuits.

[0481] The pixel circuit shown in FIG. 21A includes six transistors (transistors 303_1 to 303_3). 303_6), a capacitor 304, and a light-emitting element 305. The pixel circuit shown in FIG. 1 includes wirings 301_1 to 301_5, a wiring 302_1, and a wiring 30 2_2 are electrically connected. For example, a P-channel transistor can be used.

[0482] The pixel circuit shown in FIG. 21B is the pixel circuit shown in FIG. 21A, except that a transistor 303 21(B) is configured to add a wiring 301_6 and a wiring 301_7. The wiring 301_5 and the wiring 301_6 are electrically connected. may be electrically connected to each other. For example, a P-channel transistor can be used.

[0483] The pixel circuit shown in FIG. 22A includes six transistors (transistors 308_1 to 308_3). 308_6), a capacitor 304, and a light-emitting element 305. The pixel circuit shown in FIG. Here, the wiring 306_1 and the wiring 306_3 are electrically connected. The transistors 308_1 to 308_6 may be electrically connected. For example, a P-channel transistor can be used.

[0484] The pixel circuit shown in FIG. 22B includes two transistors (transistor 309_1 and transistor 309_2). transistor 309_2) and two capacitance elements (capacitance element 304_1 and capacitance element 304_ 2) and a light-emitting element 305. In addition, the pixel circuit shown in FIG. The wirings 11_1 to 311_3, the wiring 312_1, and the wiring 312_2 are electrically connected to each other. In addition, by configuring the pixel circuit as shown in FIG. 22(B), for example, The transistor 309 can be a current-driven type (also called a CVCC type). For example, a P-channel transistor can be used for the transistors 1 and 309_2. .

[0485] Furthermore, the light-emitting element of one embodiment of the present invention may be an active matrix light-emitting element having an active element in a pixel of a display device. The display device is a passive matrix type that does not have active elements in the pixels. It can be applied to each method.

[0486] In the active matrix system, the active element (active element, nonlinear element) is a transistor. By using not only transistors but also various active elements (active elements, nonlinear elements), For example, MIM (Metal Insulator Metal) or T It is also possible to use FD (Thin Film Diode) and other elements. Since the number of manufacturing steps is small, it is possible to reduce manufacturing costs and improve yields. Alternatively, these elements can improve the aperture ratio due to their small size. This makes it possible to achieve low power consumption and high brightness.

[0487] Other than the active matrix type, active elements (active elements, nonlinear elements) It is also possible to use a passive matrix type that does not use active elements (active elements). Since it does not use any nonlinear elements, there are fewer manufacturing steps, which reduces manufacturing costs and improves yield. Alternatively, active elements (active elements, non-linear elements) can be used. Since the aperture ratio is not increased, it is possible to achieve low power consumption or high brightness. This can be done.

[0488] The structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. can be done.

[0489] (Embodiment 6) In this embodiment, a display device including a light-emitting element of one embodiment of the present invention and a display device including the light-emitting element An electronic device having an input device attached thereto will be described with reference to FIGS. 23 to 27. FIG.

[0490] <Touch panel explanation 1> In the present embodiment, an example of an electronic device is a device that combines a display device and an input device. The touch panel 2000 will be described. The case where the .sigma.sub.2 is included will be described.

[0491] 23(A) and 23(B) are perspective views of the touch panel 2000. In B), representative components of touch panel 2000 are shown for clarity.

[0492] The touch panel 2000 includes a display device 2501 and a touch sensor 2595 (see FIG. 2). 3(B)). The touch panel 2000 also includes a substrate 2510, a substrate 2570, and a substrate The substrate 2510, the substrate 2570, and the substrate 2590 are all However, any one of the substrates 2510, 2570, and 2590 is flexible. Alternatively, one or all of the components may be configured to be non-flexible.

[0493] The display device 2501 has a plurality of pixels on a substrate 2510 and a display device that can supply signals to the pixels. The plurality of wirings 2511 are arranged around the periphery of the substrate 2510. The wire is routed through a cable, part of which forms the terminal 2519. The terminal 2519 is an FPC2509 (1). In addition, the plurality of wirings 2511 are electrically connected to the signal line driver circuit 2503s ( The signal from 1) can be fed to multiple pixels.

[0494] The substrate 2590 is electrically connected to the touch sensor 2595. The plurality of wirings 2598 are routed around the periphery of the substrate 2590. The terminal is electrically connected to the FPC2509(2). In FIG. 23(B), for clarity, the back side of the substrate 2590 (substrate 2510 The electrodes and wiring of the touch sensor 2595 provided on the surface opposite to the touch sensor 2595 are shown by solid lines. .

[0495] As the touch sensor 2595, for example, a capacitance type touch sensor can be applied. The capacitive type includes a surface type electrostatic capacitance type and a projected type electrostatic capacitance type.

[0496] The projected capacitive type is mainly divided into self-capacitance type and mutual capacitance type, which differ mainly in the driving method. The mutual capacitance method is preferable because it allows simultaneous multi-point detection.

[0497] The touch sensor 2595 shown in FIG. 23(B) is a projected capacitive touch sensor. This is a configuration in which the

[0498] The touch sensor 2595 can detect the proximity or contact of a detection object such as a finger. Various sensors can be applied.

[0499] The projected capacitive touch sensor 2595 has an electrode 2591 and an electrode 2592. The electrode 2591 is electrically connected to one of the plurality of wirings 2598, and the electrode 2592 is It is electrically connected to any other of the plurality of wirings 2598.

[0500] As shown in FIGS. 23(A) and 23(B), the electrodes 2592 are made of a plurality of electrodes repeatedly arranged in one direction. The shape is such that the quadrilaterals are connected at their corners.

[0501] The electrode 2591 is quadrilateral and is repeated in a direction intersecting the direction in which the electrode 2592 extends. are placed.

[0502] The wiring 2594 is electrically connected to the two electrodes 2591 that sandwich the electrode 2592. In this case, it is preferable that the area of ​​the intersection between the electrode 2592 and the wiring 2594 is as small as possible. This reduces the area where no electrodes are provided, reducing variations in transmittance. As a result, the variation in brightness of light passing through the touch sensor 2595 can be reduced. can be done.

[0503] The shapes of the electrodes 2591 and 2592 are not limited to this, and may take various shapes. For example, multiple electrodes 2591 are arranged with as few gaps as possible, and A plurality of electrodes 2592 are provided at intervals so that there is an area where they do not overlap with the electrodes 2591. In this case, a contact between two adjacent electrodes 2592 may be provided. Providing an insulated dummy electrode is preferable because it can reduce the area of ​​the region with different transmittance. .

[0504] <Explanation about the display device> Next, the display device 2501 will be described in detail with reference to FIG. 24(A). ) corresponds to a cross-sectional view taken along the dashed dotted line X1-X2 shown in FIG. 23(B).

[0505] The display device 2501 has a plurality of pixels arranged in a matrix. and a pixel circuit for driving the display element.

[0506] In the following description, a light emitting element that emits white light is applied to a display element. However, the display element is not limited to this. For example, To achieve different colors, light emitting elements with different luminescent colors may be applied.

[0507] The substrate 2510 and the substrate 2570 may have a water vapor permeability of, for example, 1×10 -5 g· m -2 ·day -1 Less than 1 × 10 -6 g·m -2 ·day -1 It is possible that A flexible material can be preferably used. Alternatively, the thermal expansion coefficient of the substrate 2510 and the It is preferable to use a material whose coefficient of thermal expansion is approximately equal to that of the plate 2570. For example, is 1×10 -3 / K or less, preferably 5×10 -5 / K or less, more preferably 1×10 - 5 A material having a solubility of 0.1 kJ / K or less can be suitably used.

[0508] The substrate 2510 has an insulating layer 2510a that prevents impurities from diffusing into the light-emitting element, and a flexible The substrate 2510b and the adhesive layer 2 that bonds the insulating layer 2510a and the flexible substrate 2510b together. The substrate 2570 is a laminate having a layer 510c and a layer 510d. and a flexible substrate 2570b. 2570b and an adhesive layer 2570c that bonds them together.

[0509] The adhesive layer 2510c and the adhesive layer 2570c may be made of, for example, polyester or polyolefin. Polyimide, polycarbonate or acrylic Polyurethane resin, epoxy resin, or silicone resin can be used. Any material containing a resin having a siloxane bond can be used.

[0510] In addition, a sealing layer 2560 is provided between the substrate 2510 and the substrate 2570. It is preferable that the refractive index of the sealing material is larger than that of air. When light is extracted from the layer 2560 side, the sealing layer 2560 can also serve as an optical bonding layer. Cut.

[0511] A sealant may be formed on the outer periphery of the sealing layer 2560. As a result, the area surrounded by the substrate 2510, the substrate 2570, the sealing layer 2560, and...

Claims

1. A hole injection layer and a light emitting layer are disposed between a pair of electrodes, the hole injection layer comprises a material exhibiting electron accepting properties, the light-emitting layer comprises a phosphorescent material and a host material; the LUMO level of the phosphorescent material is lower than the LUMO level of the host material; an energy difference between a LUMO level and a HOMO level of the phosphorescent material is greater than an energy difference between a LUMO level and a HOMO level of the host material; a light-emitting element, wherein an energy difference between a LUMO level of the phosphorescent material and a HOMO level of the host material is equal to or greater than a transition energy calculated from an absorption edge in an absorption spectrum of the phosphorescent material.

2. A hole injection layer and a light emitting layer are disposed between a pair of electrodes, the hole injection layer comprises a material exhibiting electron accepting properties, the light-emitting layer comprises a phosphorescent material and a host material; the LUMO level of the phosphorescent material is lower than the LUMO level of the host material; an energy difference between a LUMO level and a HOMO level of the phosphorescent material is greater than an energy difference between a LUMO level and a HOMO level of the host material; A light-emitting element, wherein an energy difference between a LUMO level of the phosphorescent material and a HOMO level of the host material is equal to or greater than an emission energy exhibited by the phosphorescent material.

3. In claim 2, A light-emitting device, wherein the emission energy of the phosphorescent material is derived from the emission peak wavelength on the shortest wavelength side among emission peaks (maximum or shoulder) of an emission spectrum.

4. In claim 2, A light-emitting element, wherein the energy of the light emitted by the phosphorescent material is derived from a wavelength at the rising edge on the shortest wavelength side of an emission spectrum.

5. In any one of claims 1 to 4, a difference in energy between a LUMO level and a HOMO level of the phosphorescent material is 0.4 eV or more larger than a transition energy calculated from an absorption edge in an absorption spectrum of the phosphorescent material.

6. In any one of claims 1 to 4, A light-emitting element, wherein an energy difference between a LUMO level and a HOMO level of the phosphorescent material is 0.4 eV or more larger than an emission energy exhibited by the phosphorescent material.

7. In any one of claims 1 to 6, The host material has a function of providing excitation energy to the phosphorescent material.

8. In any one of claims 1 to 7, The phosphorescent material comprises any one of ruthenium, rhodium, palladium, osmium, iridium, and platinum.

9. In any one of claims 1 to 8, The phosphorescent material emits light.

10. In any one of claims 1 to 9, The host 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.

11. In any one of claims 1 to 10, The host material has a function of exhibiting thermally activated delayed fluorescence at room temperature.

12. In any one of claims 1 to 11, The material exhibiting an electron accepting property is an organic compound having a halogen group or a cyano group.

13. In any one of claims 1 to 12, The HOMO level and the LUMO level of the light-emitting element are values ​​calculated from measurements by a cyclic voltammetry (CV) method.

14. A light-emitting element according to any one of claims 1 to 13, At least one of a color filter or a transistor; A display device having the above configuration.

15. A display device according to claim 14; At least one of a housing or a touch sensor; An electronic device having the

16. A light-emitting element according to any one of claims 1 to 13, At least one of a housing or a touch sensor; A lighting device having the above structure.

Images