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 aspect of the present invention relates to a light-emitting element, or a display device having the light-emitting element, an electronic device, and a light Regarding lighting equipment.

[0002] Furthermore, one aspect of the present invention is not limited to the above-mentioned technical field. One aspect of the technical field relates to a product, method, or method of manufacture. Or, one aspect of the present invention. This refers to a process, machine, manufacture, or composition. Regarding the ter. Therefore, the technical aspects of one aspect of the present invention disclosed more specifically herein Examples include semiconductor devices, display devices, liquid crystal display devices, light-emitting devices, lighting devices, energy storage devices, and memory devices. Examples include devices, methods for driving them, or methods for manufacturing them. . [Background technology]

[0003] In recent years, electroluminescence (EL) Research and development of light-emitting devices using this technology are actively underway. The basic configuration of these light-emitting devices is The device has a configuration in which a layer containing a light-emitting material (EL layer) is sandwiched between a pair of electrodes. By applying a voltage between them, light emission can be obtained from the light-emitting material.

[0004] Since the aforementioned light-emitting element is self-illuminating, the display device using it has excellent visibility and is battery-powered. It has advantages such as not requiring crystalline materials and consuming less power. Furthermore, it can be manufactured to be thin and lightweight. Furthermore, this display device also has advantages such as a high response speed.

[0005] An EL element that uses an organic material as the light-emitting material and has an EL layer containing the light-emitting material between a pair of electrodes. In the case of a child (for example, an organic EL element), by applying a voltage between a pair of electrodes, the cathode... Electrons are injected from the anode, and holes are injected from the anode into the light-emitting EL layer, causing an electric current to flow. Then, the injected electrons and holes recombine, causing the luminescent organic material to become excited. In this state, light emission can be obtained from excited, luminescent organic materials.

[0006] The types of excited states that organic materials can form include singlet excited states (S * ) and triplet excited state state(T * ) There are two states: fluorescence from the singlet excited state and phosphorescence from the triplet excited state. It is called [name]. Furthermore, the statistical generation ratio of these in light-emitting elements is S * :T * =1 :3. Therefore, phosphorescence is emitted from a light-emitting element that uses a fluorescent material (fluorescent material). Light-emitting devices that use phosphorescent materials can achieve higher luminescence efficiency. Therefore, using a phosphorescent material capable of converting the energy of the triplet excited state into light emission, The development of light-emitting elements has been actively pursued in recent years (see, for example, Patent Document 1).

[0007] The energy required to excite an organic material is the LUMO level and HOMO level of the organic material. It depends on the energy difference with the state, and that energy difference is roughly equivalent to the energy of the singlet excited state. In light-emitting devices using phosphorescent organic materials, the triplet excitation energy is It is converted into the energy of light emission. Therefore, the singlet excited state and triplet excited state formed by organic materials When the energy difference between the excited and excited states is large, the energy required to excite an organic material is Therefore, the energy equivalent to this energy difference becomes higher than the energy of the light emission. The energy difference between the energy required to excite organic materials and the energy of light emission. This affects the element characteristics in light-emitting elements as an increase in the driving voltage. Therefore, the driving voltage Methods for reducing pressure are under development (see Patent Document 2).

[0008] Furthermore, among light-emitting elements using phosphorescent materials, in particular, light-emitting elements that emit blue light... Because it is difficult to develop stable organic materials with high triplet excitation energy levels, It has not yet been put into practical use. Therefore, a highly reliable phosphorescent light-emitting element that exhibits high luminescence efficiency is needed. Child development is needed. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 2010-182699 [Patent Document 2] Japanese Patent Publication No. 2012-212879 [Overview of the project] [Problems that the invention aims to solve]

[0010] Iridium complexes are known as phosphorescent materials that exhibit high luminescence efficiency. As an iridium complex possessing energy, a pyridine skeleton or a nitrogen-containing five-membered heterocyclic skeleton is used. Iridium complexes containing ligands are known. These include pyridine skeletons or nitrogen-containing five-membered heterocycles. The skeleton has high triplet excitation energy, but its electron-accepting ability is low, therefore these skeletons Iridium complexes with ligands have high HOMO and LUMO levels, and hole carriers While electrons are easily injected, electron carriers are not easily injected. Therefore, electron-accepting properties are more important. Development is underway to create iridium complexes with a robust ligand structure.

[0011] On the other hand, iridium complexes with a ligand that has a highly electron-accepting skeleton have a HOMO level and The LUMO level is low, making it easy for electron carriers to be injected, while hole carriers are difficult to inject. Therefore, excitation by direct carrier recombination is difficult, and the light-emitting element does not emit light efficiently. It can sometimes be difficult to get them to do it.

[0012] Therefore, in one aspect of the present invention, a light-emitting element having a phosphorescent material has high luminescence efficiency. One of the objectives is to provide a light-emitting element. Alternatively, in one aspect of the present invention, the power consumption is One of the objectives is to provide a light-emitting element with reduced emission. Alternatively, in one aspect of the present invention, One of the objectives is to provide a light-emitting element with excellent reliability. Alternatively, in one aspect of the present invention, One of the objectives is to provide a novel light-emitting element. Alternatively, in one aspect of the present invention, One objective is to provide a light-emitting device. Alternatively, in one aspect of the present invention, a novel display device One of the objectives is to provide a suitable location.

[0013] Furthermore, the description of the above problems does not preclude the existence of other problems. Also, one aspect of the present invention is not necessarily However, it is not necessary to solve all of these problems. Other issues not mentioned above should be described in the specification, etc. This is self-evident, and it is possible to extract issues other than those mentioned above from the description in the specification, etc. ru. [Means for solving the problem]

[0014] One aspect of the present invention relates to a light-emitting material having a host material capable of efficiently exciting a phosphorescent material. It is an element.

[0015] Therefore, one aspect 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 that of the host material, and the guest material The energy difference between the LUMO level and the HOMO level is the energy difference between the LUMO level and the HOMO level of the host material. When the energy difference with the level is greater, the guest material converts the triplet excitation energy into light emission. It is a light-emitting element that has the function of being able to do so.

[0016] Another aspect 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 UMO level and the HOMO level is the energy difference between the LUMO level and the HOMO level of the host material. When the energy difference with the position is greater, the guest material converts the triplet excitation energy into light emission. It has the ability to perform the following functions: the LUMO level of the guest material and the HOMO level of the host material. 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, more than just energy.

[0017] Another aspect 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 UMO level and the HOMO level is the energy difference between the LUMO level and the HOMO level of the host material. When the energy difference with the position is greater, the guest material converts the triplet excitation energy into light emission. It has the ability to perform the following functions: the LUMO level of the guest material and the HOMO level of the host material. This is a light-emitting element in which the energy difference is greater than or equal to the energy of the light emitted by the guest material.

[0018] Furthermore, in each of the above configurations, the energy between the LUMO level and the HOMO level of the guest material The difference is calculated from the transition energy derived from the absorption edge in the absorption spectrum of the guest material. A value of 0.4 eV or greater is preferable. Also, the relationship between the LUMO level and the HOMO level of the guest material. The energy difference should be at least 0.4 eV greater than the energy of the luminescence exhibited by the guest material. It seems so.

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

[0020] Furthermore, in each of the above configurations, the host material provides excitation energy to the guest material. It is preferable that it has the ability. Also, the emission spectrum of the emission exhibited by the host material is the same as that of the guest material. It is preferable that it has a wavelength region that overlaps with the lowest energy absorption band in the absorption spectrum. It seems so.

[0021] Furthermore, in each of the above configurations, it is preferable that the guest material contains iridium. It is preferable that the material exhibits luminescence.

[0022] Furthermore, in each of the above configurations, the host material has the function of transporting electrons. The host material preferably has the ability to transport holes. It has a π-electron-deficient heteroaromatic ring skeleton, and the host material has a π-electron-rich heteroaromatic ring skeleton. It is preferable that it has at least one of the aromatic amine skeletons. Also, π-electron-deficient complex aromatics The ring skeleton has at least one of a diazine skeleton or a triazine skeleton, and is π-electron-rich. The heteroatom ring skeletons include the acridine skeleton, phenoxazine skeleton, phenothiazine skeleton, and furan. Preferably, it has at least one of a skeleton, a thiophene skeleton, and a pyrrole skeleton.

[0023] Furthermore, in the light-emitting element described in each of the above configurations, the host material is the following structural formula (500) It is preferable that the compound is represented by any one of (503). [ka] Another aspect of the present invention is represented by any one of the following structural formulas (500) to (503). It is a compound that is used for this purpose. [ka]

[0024] Another aspect of the present invention involves the light-emitting element of each of the above configurations and a color filter or transistor. A display device having at least one zista. Another aspect of the present invention is the said It is an electronic device having a display device and at least one of a housing or a touch sensor. Another aspect of the present invention relates to the light-emitting element of each of the above configurations and at least one housing or touch sensor. It is a lighting device having one and a light-emitting device. Another aspect of the present invention is a light-emitting device having a light-emitting element. Furthermore, electronic devices having light-emitting devices are also included in the scope. Therefore, light emission in this specification The term "device" refers to an image display device or a light source (including lighting devices). Furthermore, it refers to a light-emitting device. Connectors, for example, FPC (Flexible Printed Circuit), T Module with CP (Tape Carrier Package) attached, TC A module with a printed circuit board attached to the end of P, or a light-emitting element with COG (Chip Modules in which ICs (integrated circuits) are directly mounted using the On Glass method are also part of this invention. This is one aspect of the situation. [Effects of the Invention]

[0025] According to one aspect of the present invention, a light-emitting element having a phosphorescent material has high luminescence efficiency. This can provide a light-emitting element with reduced power consumption according to one aspect of the present invention. It can provide a child. Or, according to one aspect of the present invention, a highly reliable light-emitting element can be provided. It can be provided. Or, according to one aspect of the present invention, a novel light-emitting element can be provided. This is possible. Alternatively, according to one aspect of the present invention, a novel light-emitting device can be provided. Alternatively, according to one aspect of the present invention, a novel display device can be provided.

[0026] Furthermore, the description of these effects does not preclude the existence of other effects. One aspect of the present invention is: It is not necessarily required to have all of these effects. Other effects are described in the specification. This is obvious from the descriptions in the specifications, drawings, and claims, and the descriptions in the specifications, drawings, and claims Therefore, it is possible to extract effects other than those mentioned above. [Brief explanation of the drawing]

[0027] [Figure 1] A schematic cross-sectional view of a light-emitting element according to one embodiment of the present invention. [Figure 2] A schematic diagram illustrating the correlation of energy levels and the correlation of energy bands in the light-emitting layer of a light-emitting element according to one embodiment of the present invention. [Figure 3] A schematic cross-sectional view of a light-emitting element according to one embodiment of the present invention. [Figure 4] A schematic diagram illustrating the correlation of energy levels and the correlation of energy bands in the light-emitting layer of a light-emitting element according to one embodiment of the present invention. [Figure 5]A schematic cross-sectional view of a light-emitting element according to one aspect of the present invention, and a schematic diagram illustrating the correlation of energy levels related to the light-emitting layer. [Figure 6] A schematic cross-sectional view of a light-emitting element according to one aspect of the present invention, and a schematic diagram illustrating the correlation of energy levels related to the light-emitting layer. [Figure 7] A schematic cross-sectional view of a light-emitting element according to one embodiment of the present invention. [Figure 8] A schematic cross-sectional view of a light-emitting element according to one embodiment of the present invention. [Figure 9] A schematic cross-sectional diagram illustrating a method for manufacturing a light-emitting element according to one embodiment of the present invention. [Figure 10] A schematic cross-sectional diagram illustrating a method for manufacturing a light-emitting element according to one embodiment of the present invention. [Figure 11] A top view and a schematic cross-sectional view illustrating a display device according to one embodiment of the present invention. [Figure 12] A schematic cross-sectional view illustrating a display device according to one embodiment of the present invention. [Figure 13] A schematic cross-sectional view illustrating a display device according to one embodiment of the present invention. [Figure 14] A schematic cross-sectional view illustrating a display device according to one embodiment of the present invention. [Figure 15] A schematic cross-sectional view illustrating a display device according to one embodiment of the present invention. [Figure 16] A schematic cross-sectional view illustrating a display device according to one embodiment of the present invention. [Figure 17] A schematic cross-sectional view illustrating a display device according to one embodiment of the present invention. [Figure 18] A schematic cross-sectional view illustrating a display device according to one embodiment of the present invention. [Figure 19] A schematic cross-sectional view illustrating a display device according to one embodiment of the present invention. [Figure 20] A block diagram and a circuit diagram illustrating a display device according to one embodiment of the present invention. [Figure 21] A circuit diagram illustrating the pixel circuit of a display device according to one embodiment of the present invention. [Figure 22] A circuit diagram illustrating the pixel circuit of a display device according to one embodiment of the present invention. [Figure 23] A perspective view showing an example of a touch panel according to one aspect of the present invention. [Figure 24]A cross-sectional view showing an example of a display device and a touch sensor according to one embodiment of the present invention. [Figure 25] A cross-sectional view showing an example of a touch panel according to one aspect of the present invention. [Figure 26] A block diagram and timing chart diagram of a touch sensor according to one aspect of the present invention. [Figure 27] A circuit diagram of a touch sensor according to one aspect of the present invention. [Figure 28] A perspective view illustrating a display module according to one embodiment of the present invention. [Figure 29] A diagram illustrating an electronic device according to one embodiment of the present invention. [Figure 30] A diagram illustrating an electronic device according to one embodiment of the present invention. [Figure 31] A diagram illustrating an electronic device according to one embodiment of the present invention. [Figure 32] A perspective view illustrating a display device according to one embodiment of the present invention. [Figure 33] A perspective view and a cross-sectional view illustrating a light-emitting device according to one embodiment of the present invention. [Figure 34] A cross-sectional view illustrating a light-emitting device according to one embodiment of the present invention. [Figure 35] A diagram illustrating a lighting device and electronic equipment according to one embodiment of the present invention. [Figure 36] A diagram illustrating a lighting device according to one embodiment of the present invention. [Figure 37] A schematic cross-sectional view illustrating a light-emitting element according to an embodiment. [Figure 38] A diagram illustrating the current efficiency-luminance characteristics of a light-emitting element according to an embodiment. [Figure 39] A diagram illustrating the brightness-voltage characteristics of a light-emitting element according to an embodiment. [Figure 40] A diagram illustrating the external quantum efficiency-luminance characteristics of a light-emitting element according to an embodiment. [Figure 41] A diagram illustrating the power efficiency-luminance characteristics of a light-emitting element according to an embodiment. [Figure 42] A diagram illustrating the electroluminescence spectrum of a light-emitting element according to an embodiment. [Figure 43] A diagram illustrating the emission spectrum of the host material in the example. [Figure 44] A diagram illustrating the transient fluorescence characteristics of the host material in the example. [Figure 45] A diagram illustrating the absorption and emission spectra of the guest material in the example. [Figure 46] A diagram illustrating the current efficiency-luminance characteristics of a light-emitting element according to an embodiment. [Figure 47] A diagram illustrating the brightness-voltage characteristics of a light-emitting element according to an embodiment. [Figure 48] A diagram illustrating the external quantum efficiency-luminance characteristics of a light-emitting element according to an embodiment. [Figure 49] A diagram illustrating the power efficiency-luminance characteristics of a light-emitting element according to an embodiment. [Figure 50] A diagram illustrating the electroluminescence spectrum of a light-emitting element according to an embodiment. [Figure 51] A diagram illustrating the emission spectrum of the host material in the example. [Figure 52] A diagram illustrating the absorption and emission spectra of the guest material in the example. [Figure 53] A diagram illustrating the current efficiency-luminance characteristics of a light-emitting element according to an embodiment. [Figure 54] A diagram illustrating the brightness-voltage characteristics of a light-emitting element according to an embodiment. [Figure 55] A diagram illustrating the external quantum efficiency-luminance characteristics of a light-emitting element according to an embodiment. [Figure 56] A diagram illustrating the power efficiency-luminance characteristics of a light-emitting element according to an embodiment. [Figure 57] A diagram illustrating the electroluminescence spectrum of a light-emitting element according to an embodiment. [Figure 58] A diagram illustrating the emission spectrum of the host material in the example. [Figure 59] A diagram illustrating the emission spectrum of the host material in the example. [Figure 60]This figure shows the 1H NMR chart of N-(4-biphenyl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-N-{4-[3-(dibenzo[f,h]quinoxaline-2-yl)phenyl]phenyl}amine (abbreviation: 2mpFBiBPDBq). [Figure 61] This figure shows the results of the LC / MS analysis of 2mpFBiBPDBq. [Figure 62] This figure shows the absorption and emission spectra of a toluene solution of 2mpFBiBPDBq. [Figure 63] This figure shows the absorption and emission spectra of a solid thin film of 2mpFBiBPDBq. [Figure 64] A diagram showing the 1H NMR chart of N-(4-biphenyl)-N-(4-{6-[3-(dibenzo[f,h]quinoxaline-2-yl)phenyl]dibenzofuran-4-yl}phenyl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: 2mFBiPDBfPDBq). [Figure 65] This figure shows the absorption and emission spectra of a toluene solution of 2mFBiPDBfPDBq. [Figure 66] This figure shows the absorption and emission spectra of a solid thin film 2mFBiPDBfPDBq. [Figure 67] A diagram showing the 1H NMR chart of 4-[3-(dibenzo[f,h]quinoxaline-2-yl)phenyl]-4'-(9-phenyl-9H-carbazole-3-yl)-triphenylamine (abbreviation: 2mpPCBABPDBq). [Figure 68] This figure shows the absorption and emission spectra of a toluene solution of 2mpPCBABPDBq. [Figure 69] This figure shows the absorption and emission spectra of a solid thin film of 2mpPCBABPDBq. [Figure 70] This figure shows the 1H NMR chart of N-phenyl-N-[(1,1'-biphenyl)-4-yl]-N-{4-[3-(dibenzo[f,h]quinoxaline-2-yl)phenyl]phenyl}amine (abbreviation: 2mpBPABPDBq). [Figure 71]This figure shows the results of the LC / MS analysis of 2mpBPABPDBq. [Figure 72] This figure shows the absorption and emission spectra of a toluene solution of 2mpBPABPDBq. [Figure 73] This figure shows the absorption and emission spectra of a solid thin film of 2mpBPABPDBq. [Modes for carrying out the invention]

[0028] The embodiments of the present invention will be described in detail below with reference to the drawings. However, the present invention is as follows The description is not limited to the present invention, and the form and details may not depart from the spirit and scope of the present invention. It is possible to change this in various ways. Therefore, the present invention can be described in the embodiments shown below. It is not interpreted as being limited to volume.

[0029] For the sake of ease of understanding, the position, size, and scope of each component shown in the drawings, etc., are as follows: The actual location, size, and range may not be represented. Therefore, the disclosed invention may not reflect the actual location, size, or range. It is not necessarily limited to the location, size, or scope disclosed in drawings, etc.

[0030] Furthermore, in this specification, the ordinal numbers used as "1st," "2nd," etc., are used for convenience. The order of processes or stacking may not be indicated. For example, "the first" may be written as "the second" or This can be replaced with "third," etc., as appropriate in the explanation. The ordinal numbers used to specify one aspect of this invention may not be the same. be.

[0031] Furthermore, in this specification and other documents, when describing the structure of the invention using drawings, the same thing is used The symbols used may be consistent across different drawings.

[0032] Furthermore, in this specification, the terms "membrane" and "layer" are interchangeable. It is possible to change the term. For example, the term "conductive layer" can be changed to the term "conductive film." It may be possible to change it. Or, for example, change the term "insulating film" to "insulating layer". In some cases, it may be possible to change the terminology to this.

[0033] In this specification, etc., the singlet excited state (S * ) is a single with excitation energy It refers to a singlet state. Furthermore, the S1 level is the lowest singlet excitation energy level. This refers to the lowest excitation energy level of the singlet excited state. Also, the triplet excited state. (T * ) is a triplet state that has excitation energy. Also, the T1 level is a triplet state. This is the lowest level of the term excitation energy levels, and the excitation energy of the lowest triplet excited state. This refers to an energy level. In this specification, the terms singlet excited state and singlet excited energy level are used interchangeably. Even when referred to as energy levels, they represent the lowest singlet excited states and S1 levels. There are cases where this is the case. Also, when referred to as triplet excited state and triplet excited energy level, However, it may represent the lowest triplet excited state and T1 level.

[0034] Furthermore, in this specification, a fluorescent material is defined as a material that relaxes from a singlet excited state to a ground state. It is a material that emits light in the visible light region. On the other hand, phosphorescent materials are materials that emit light from a triplet excited state to a ground state. It is a material that emits light in the visible light region at room temperature when it relaxes to a certain state. In other words, phosphorus Optical materials are materials that can convert triplet excitation energy into visible light.

[0035] Furthermore, the phosphorescence emission energy or triplet excitation energy is the shortest wavelength side of the phosphorescence emission. It can be derived from the emission peak (including the shoulder) or the rising wavelength. Oh, this phosphorescence emission is time-resolved photoluminescence in a low-temperature environment (e.g., 10K). It can be observed by performing the spectroscopy method. Furthermore, the emission energy of thermally activated delayed fluorescence is , the shortest wavelength emission peak (including the shoulder) or rise time of thermally activated delayed fluorescence It can be derived from the wavelength.

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

[0037] Furthermore, in this specification, the blue wavelength region refers to waves between 400 nm and 500 nm. It is a long region, and blue emission means that there is at least one emission spectral peak in that region. It is light emission. Furthermore, the green wavelength range is the wavelength range between 500 nm and less than 580 nm. Green emission is defined as emission having at least one emission spectral peak in that region. Furthermore, the red wavelength range is the wavelength range between 580 nm and 680 nm, and the red wavelength range is Emission is defined as emission having at least one emission spectral peak in the region.

[0038] (Embodiment 1) In this embodiment, a light-emitting element according to one aspect of the present invention will be described below using Figures 1 to 4. I will reveal it.

[0039] <Example of light-emitting element configuration 1> First, regarding the configuration of a light-emitting element according to one aspect of the present invention, use Figures 1(A) and (B) to show the following: I will explain below.

[0040] Figure 1(A) is a schematic cross-sectional view of a light-emitting element 150 according to one embodiment of the present invention.

[0041] The light-emitting element 150 has a pair of electrodes (electrode 101 and electrode 102), and between the pair of electrodes It has an EL layer 100 provided therein. The EL layer 100 has at least an emissive layer 130. .

[0042] Furthermore, the EL layer 100 shown in Figure 1(A) includes, in addition to the light-emitting layer 130, a hole injection layer 111, and It has functional layers such as a pore 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 used as the anode, and electrode 1 Although 02 is described as the cathode, this is not the case for the configuration of the light-emitting element 150. Then, electrode 101 is used as the cathode and electrode 102 as the anode, and the stacking of each layer between these electrodes is done in the reverse order. It may also be arranged in this order. That is, from the anode side, a hole injection layer 111, a hole transport layer 112, and The order in which the optical layer 130, electron transport layer 118, and electron injection layer 119 are stacked should be as follows. .

[0044] Note that the configuration of the EL layer 100 is not limited to the configuration shown in Figure 1(A), and the hole injection layer 111 At least one of the hole transport layer 112, electron transport layer 118, and electron injection layer 119 selected It is sufficient to have a configuration that has one of either. Alternatively, the EL layer 100 can be a hole or electron injection To reduce barriers, to improve hole or electron transport, to reduce hole or electron transport It has a functional layer that has functions such as being able to suppress the quenching phenomenon caused by electrodes. It may also be configured as follows. Note that even if each functional layer is a single layer, a configuration in which multiple layers are stacked may also be possible. It may be possible.

[0045] Figure 1(B) is a schematic cross-sectional view showing an example of the light-emitting layer 130 shown in Figure 1(A). The light-emitting layer 130 shown in B) comprises a guest material 131 and a host material 132.

[0046] Furthermore, 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 the host material 132.

[0047] Furthermore, as the guest material 131, any luminescent organic material may be used. The material is preferably one that has the function of converting triplet excitation energy into light emission. Furthermore, it is preferable that the material is capable of emitting phosphorescence (hereinafter also referred to as a phosphorescent material). In the following explanation, we will describe a configuration in which a phosphorescent material is used as guest material 131. Therefore, guest material 131 may be interpreted as phosphorescent material.

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

[0049] In one embodiment of the present invention, the light-emitting element 150 comprises a pair of electrodes (electrode 101 and electrode 102 By applying a voltage between them, electrons are released from the cathode and holes from the anode. The electrons and holes are injected into the EL layer 100, and an electric current flows. Then, the injected electrons and holes recombine. By doing so, the guest material 131 in the light-emitting layer 130 of the EL layer 100 is excited. This allows light emission to be obtained from the excited guest material 131.

[0050] Furthermore, light emission from 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. Carriers (electrons and positive holes) recombine in the guest material 131 to form an excited state of the guest material 131 . At this time, the energy required to excite the guest material 131 by the direct recombination process of carriers is dependent on the energy difference between the lowest unoccupied molecular orbital (also referred to as LUMO) level and the highest occupied molecular orbital (Hi ghest occupied molecular orbital, also referred to as HOMO level) of the guest material 131, and this energy difference generally corresponds to 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 is converted into light emission. Therefore, when there is a large energy difference between the singlet excited state and the triplet excited state formed by the guest material 131, the energy required to excite the guest material 131 is higher than the energy of the light emission by an amount corresponding to the energy difference. The energy difference between the energy required to excite the guest material 131 and the energy of the light emission affects the device characteristics as a difference in driving voltage in the light-emitting device. Therefore, in the (

[0052] α) direct recombination process, the light emission start voltage of the light-emitting device becomes larger than the voltage corresponding to the energy of the light emission in the guest material 131 . <00009l6> Moreover, when the guest material 131 has a high light emission energy, since the LUMO level of the guest material 131 becomes high, it becomes difficult for electrons as carriers to be injected into the guest material 131

[0053] In the guest material 131, direct recombination of carriers (electrons and holes) is less likely to occur. Therefore, it is difficult to obtain high luminous efficiency in the light-emitting device.

[0054] ≪(β) Energy transfer process≫ Next, in order 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. In Fig. 2(A), the notations and symbols are as follows. ·Guest(131): Guest material 131 (phosphorescent material) ·Host(132): Host material 132 ·S G : S1 level of the guest material 131 (phosphorescent material) ·T G : T1 level of the guest material 131 (phosphorescent material) ·S H : S1 level of the host material 132 ·T H : T1 level of the host material 132

[0055] When carriers recombine in the host material 132 and singlet and triplet excited states of the host material 132 are formed, as shown in route E1 and route E2 in Fig. 2(A), both the singlet excitation energy and the triplet excitation energy of the host material 132 transfer from the singlet excitation energy level (S ) and the triplet excitation energy level H of the host material 132 to the triplet excitation energy level (T ) of the guest material 131, and the guest material H 131 becomes a triplet excited state. From the guest material 131 in the triplet excited state, G phosphorescence emission can be obtained. Note that the singlet excitation energy level (S ) of the host material 132

[0056]

[0057] [[ID=6)8]]

[0058]

[0059]

[0060]

[0061]

[0062] H ) and triplet excitation energy levels (T H ) are both higher than the triplet excitation energy level (T G ) of the guest material 131. By doing so, the singlet excitation energy and triplet excitation energy of the generated host material 132 can be efficiently energy - transferred from the singlet excitation energy level (S H ) and triplet excitation energy level (T H ) of the host material 132 to the triplet excitation energy level (T G ) of the guest material 131.

[0057] In other words, in the light - emitting layer 130, there is an excitation energy donation from the host material 132 to the guest material 131.

[0058] In the case where the light - emitting layer 130 has materials other than the host material 132 and the guest material 131, it is preferable that the light - emitting layer 130 has a material with a triplet excitation energy level higher than the triplet excitation energy level (T H ) of the host material 132. This makes it less likely for quenching of the triplet excitation energy of the host material 132 to occur, and energy transfer to the guest material 131 occurs efficiently.

[0059] Also, in order to reduce the energy loss when the singlet excitation energy of the host material 132 moves to the triplet excitation energy level (T G ) of the guest material 131, it is preferable that the energy difference between the singlet excitation energy level (S H ) and the triplet excitation energy level (T H ) of the host material 132 is small.

[0060] ​​ Here, Figure 2(B) shows the energy band diagrams of the guest material 131 and the host material 132. This is shown. In Figure 2(B), Guest(131) represents guest material 131, and Hos t(132) represents the host material 132, and ΔE G The LUMO levels of guest material 131 and H This represents the energy difference with the OMO level, ΔE H The LUMO levels of host material 132 and HOM This represents the energy difference with the O level, ΔE B This is the LUMO level of guest material 131 and the host material This notation and symbol represent the energy difference with respect to the 132 HOMO level.

[0061] The emission exhibited by guest material 131 has a short wavelength and high emission energy. To achieve this, the energy difference (ΔE) between the LUMO level and the HOMO level of guest material 131 must be G ) is preferable to be large. On the other hand, in the light-emitting element 150, in order to reduce the driving voltage It is preferable to excite with the smallest possible excitation energy, and for that purpose, the host It is preferable that the excitation energy of the excited state formed by material 132 be small. Therefore, The energy difference (ΔE) between the LUMO level and the HOMO level of the host material 132. H ) is small That is preferable.

[0062] Furthermore, since guest material 131 is a phosphorescent light-emitting material, it emits light with triplet excitation energy. It has the ability to convert to a triplet excited state. In addition, the triplet excited state is more efficient than the singlet excited state. The energy is stable. Therefore, guest material 131 has LUMO level and HOMO level and The energy difference (ΔE G ) exhibits luminescence with lower energy. Here, this guest material The energy difference (ΔE) between the LUMO level and the HOMO level of material 131 G ) but host material 13 The energy difference (ΔE) between the LUMO level and the HOMO level of 2 H Even if it is greater than ) The luminescence energy (abbreviated as ΔE) exhibited by guest material 131. Em ) or absorption spectrum The transition energy (abbreviated as ΔE) calculated from the absorption edge at abs ) is ΔE H Equivalent to If the value is smaller, the excited state formed by the host material 132 will be converted to the guest material 13 This allows for the transfer of excitation energy to 1, and light emission can be obtained from the guest material 131. The inventors have found that the ΔE of guest material 131 G However, guest material 131 presents Luminous energy (ΔE Em ) or transition calculated from the absorption edge in the absorption spectrum Transfer energy (ΔE abs If it is greater than ), the guest material 131 is directly electrically excited. ΔE G Because a large amount of electrical energy equivalent to this is required, the driving voltage of the light-emitting element is It increases. 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, and energy transfer from there This generates an excited state for guest material 131, allowing for a low drive voltage and high efficiency, and the guest material 131 is generated. Light can be obtained from material 131. Therefore, a light-emitting element according to one aspect of the present invention can emit light. Light onset voltage (when brightness is 1 cd / m²) 2 The larger the voltage, the more light the guest material emits. Energy (ΔE Em It can be made smaller than the voltage equivalent to ΔE. G but, The luminescence energy (ΔE) exhibited by guest material 131 Em ) or in the absorption spectrum The transition energy (ΔE) calculated from the absorption edge abs If it is considerably larger than (for example, G In the case where the light source material is a blue light-emitting material, one aspect of the present invention is particularly useful. Light energy (ΔE Em ) is the emission peak (maximum value) at the shortest wavelength end of the emission spectrum. It can be derived from the wavelength of the rise (including the shoulder) or the rise time.

[0063] Furthermore, if guest material 131 contains heavy metals, spin-orbit interaction (electron spin angle) Interterm crossover between singlet and triplet states is facilitated by the interaction between momentum and orbital angular momentum. Therefore, the transition between the singlet ground state and the triplet excited state in guest material 131 is advanced. In some cases, this may be acceptable. That is, the singlet ground state and triplet excited state of guest material 131. This can increase the efficiency of luminescence and the probability of absorption involved in the transition between states. Therefore, The guest material 131 preferably contains a metallic element with a large spin-orbit interaction, and is particularly white. Metal group elements (ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium ( It is preferable that it contains Os, iridium (Ir), or platinum (Pt), and among them i The presence of lydium is involved in the direct transition between the singlet ground state and the triplet excited state. This is preferable because it increases the probability of success.

[0064] Furthermore, in order for guest material 131 to be stable and highly reliable, the L of guest material 131 A low UMO level is preferable, and for this to be achieved, the heavy metal atoms in the guest material 131 For the ligands that coordinate to it, it is preferable to have high electron-accepting properties and a low LUMO level.

[0065] Guest materials having the structure described above are molecules with a low LUMO level that readily accept electrons. It is easy to form a structure. If guest material 131 has a molecular structure that readily accepts electrons, the guest The LUMO level of material 131 may be lower than the LUMO level of host material 132. Furthermore, ΔE G is ΔE H If greater than the host level of guest material 131, The HOMO level of material 132 is lower. Note that at this time, the HOMO level of guest material 131 is lower. The energy difference between the position and the HOMO level of host material 132 is the LUM level of guest material 131. The energy difference between the O level and the LUMO level of the host material 132 becomes greater.

[0066] Here, the LUMO level of guest material 131 is lower than the LUMO level of host material 132. When the HOMO level of guest material 131 is lower than the HOMO level of host material 132 , Carriers (holes and electrons) injected from a pair of electrodes (electrode 101 and electrode 102) Of these, 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 more easily injected into the guest material 131. Therefore, an excited complex may be formed between the guest material 131 and the host material 132. In particular, the energy between the LUMO level of guest material 131 and the HOMO level of host material 132 - Difference (ΔE B ) is the energy (ΔE) of the luminescence exhibited by guest material 131. Em Smaller than ) As time progresses, the formation of an excited complex between the guest material 131 and the host material 132 increases. It becomes dominant. In this case, it becomes difficult for the excited state to be generated by the guest material 131 alone, The luminescence efficiency of the light-emitting element will decrease.

[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] The general formula (G11) is that the host material 132 receives a hole (H + ), guest ingredients 131 G receives electrons (G - ) By doing so, the host material 132 and the guest material 131 become excited complexes ((H·G) * This is a reaction that produces ). Also, the general formula (G12) is the excited state G Material 131 (G * ) and the ground state host material 132(H) interact as The host material 132 and guest material 131 are excited complex ((H·G) * ) reaction that produces The host material 132 and guest material 131 are excited complex ((H·G) * ) forms By doing so, the excited state of guest material 131 alone (G * This makes it harder for the product to be generated.

[0070] The excited complex formed by the host material 132 and the guest material 131 is L of the guest material 131. The energy difference (ΔE) between the UMO level and the HOMO level of the host material 132 B ) roughly equivalent It becomes an excited complex with an excitation energy. However, the LUM of guest material 131 The energy difference (ΔE) between the O level and the HOMO level of the host material 132 B ) but guest materials The energy of the light emitted by 131 (ΔE Em ) or the absorption edge in the absorption spectrum The transition energy (ΔE) calculated from this is abs ) When this is the case, the host material 132 and the guest The reaction that forms an excited complex with material 131 can be suppressed, and the effect from guest material 131 can be suppressed. The inventors have found that light emission can be obtained efficiently. At this time, ΔE abs but ΔE B Because it is smaller, guest material 131 readily accepts excitation energy, unlike the host material. Rather than forming an excited complex with 132 and guest material 131, guest material 131 generates an excited energy The state in which a molecule receives ghee and becomes excited results in a lower energy state and greater stability.

[0071] As mentioned above, the energy between the LUMO level and the HOMO level of guest material 131 - Difference (ΔE G ) is the energy difference between the LUMO level and the HOMO level of the host material 132 ( ΔE H Even if it is greater than ), the absorption edge in the absorption spectrum of guest material 131 The transition energy (ΔE) calculated from abs ) is ΔE H If it is equal to or smaller than that, encourage Excitation energy is efficiently transferred from the host material 132 in the initial state to the guest material 131. As a result, one of the features of this invention is that a low-voltage and highly efficient light-emitting element can be obtained. Therefore, ΔE G >ΔE H ≥ΔE abs (ΔE G is ΔE H Larger, ΔE H teeth ΔE absis as described above. Therefore, when the energy difference (ΔE ) between the LUMO level and the HOM G O level of the guest material 131 is larger than the transition energy (ΔE ) calculated from the absorption edge in the absorption spectrum of the guest material 131, the mechanism of one aspect of the present invention is suitable. More specifically, the energy difference (ΔE abs ) between the LUMO level and the HOMO level of the guest material 131 is preferably 0.3 eV or more, more preferably 0 .4 eV or more larger than the transition energy (ΔE ) calculated from the absorption edge in the absorption spectrum of the guest material 131. Further, since the energy of the light emission exhibited by the guest material 131 (ΔE G ) is equal to or smaller than ΔE , the energy difference (ΔE abs ) between the LUMO level and the HOMO level of the guest material 131 is preferably 0.3 eV or more, more preferably 0.4 eV or more larger than the energy (ΔE ) of the light emission exhibited by the guest material 131. (ΔE Em ) is, ΔE abs and the same or smaller than that, so the energy difference (ΔE ) between the LUMO level and the HOMO level of the guest material 131 is, the energy of the light emission exhibited by the guest material 131 (ΔE G ) is preferably 0.3 eV or more, more preferably 0.4 eV or more larger than the energy (ΔE ) of the light emission exhibited by the guest material 131. Em ) is preferably 0.3 eV or more, more preferably 0.4 eV or more larger than the energy (ΔE ) of the light emission exhibited by the guest material 131.

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

[0073] Furthermore, the energy difference (ΔE) between the LUMO level and the HOMO level of the host material 132 H )teeth , the singlet excitation energy level of host material 132 (S H It is equivalent to or slightly larger than ) Singlet excitation energy levels of material 132 (S H ) is the triplet excitation energy level (T H It is greater than the triplet excitation energy level (T) of the host material 132. H ) is a guest Triplet excitation energy levels of material 131 (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. H is T H Larger, T H is T G The above is the result. Furthermore, regarding the absorption spectrum of guest material 131... The absorption related to the absorption edge is between the singlet ground state and the triplet excited state of the guest material 131. When it is an absorption related to a transition, ΔT G is ΔE abs This results in energy equivalent to or slightly less than that. Therefore, ΔE G is ΔE abs To become at least 0.3eV greater, ΔE G and ΔE abs From the energy difference, S H and T H A small energy difference is preferred. More specifically, S H and T H The energy difference is preferably greater than 0 eV, which is 0.2 It is less than or equal to eV, and more preferably greater than 0 eV and less than or equal to 0.1 eV.

[0074] The energy difference between the singlet excitation energy level and the triplet excitation energy level is small, Suitable materials for material 132 include thermally activated delayed fluorescence (T) Examples include vated delayed fluorescence (TADF) materials. Thermally activated delayed fluorescence materials exhibit a difference between singlet excitation energy levels and triplet excitation energy levels. The energy difference is small, and the triplet excitation energy is reduced to the singlet excitation energy by reverse intersystem crossing. It has the function of being able to convert to. Furthermore, the host material 132 according to one aspect of the present invention and Therefore, T H From S H The reverse interterm crossing efficiency to S does not need to be high. H Light emission from Since a high yield is not required, a wide range of materials can be selected.

[0075] Furthermore, the energy difference between the singlet excitation energy level and the triplet excitation energy level is reduced. To achieve this, the host material 132 has a skeleton that has the function of transporting holes (hole transportability). It is preferable that it has a skeleton that has the function of transporting electrons (electron transportability). In this case, the excited state of the host material 132 provides the HOMO molecular orbital to the hole-transporting framework. It possesses an electron-transporting framework and has LUMO molecular orbitals, and therefore HOMO molecular orbitals The overlap with the LUMO molecular orbital becomes extremely small. In other words, a donor within a single molecule. - This makes it easier to form acceptor-type excited states, and singlet excitation energy levels and triplet excitations. The energy difference with the electromotive force level becomes smaller. Multiplet excitation energy level (S H ) and triplet excitation energy level (T H The difference between ) and is preferable The value of 'k' is greater than 0 eV and less than or equal to 0.2 eV.

[0076] Furthermore, molecular orbitals represent the spatial distribution of electrons within a molecule and can express the probability of finding an electron. It is possible. Molecular orbitals allow us to determine the electron configuration of a molecule (the spatial distribution and energy of electrons) in detail. It is possible to describe it in detail.

[0077] Furthermore, when the host material 132 has a strong donor-like skeleton, it is injected into the light-emitting layer 130. The holes are easily injected into the host material 132 and transported. Also, the host material 132 When the host material has a highly acceptor-like framework, electrons injected into the light-emitting layer 130 are released into the host material It is injected into 132 and made easier to transport. In this way, the excited state in the host material 132 This is preferable because it makes the formation process easier.

[0078] Furthermore, the emission wavelength of guest material 131 becomes short wavelength, and the emission energy (ΔE Em ) is large The more you listen, the greater the energy difference (ΔE) between the LUMO level and the HOMO level of guest material 131. G ) becomes larger, and consequently, a large amount of energy is required to directly electrically excite the guest material. Energy is required. However, in one aspect of the present invention, the absorption of guest material 131 The transition energy (ΔE) calculated from the absorption edge in the absorption spectrum abs ) is ΔE H and If they are equal or smaller, ΔE G ΔE with less energy than H With that much energy Since the strum material 131 can be excited, the power consumption of the light-emitting element can be reduced. Therefore, the transitions calculated from the absorption edges in the absorption spectrum of guest material 131 Energy (ΔE abs ) and the energy between the LUMO level and HOMO level of guest material 131 Energy difference (ΔE G ) and the greater the energy difference between them (i.e., especially blue light emission) In the case of a guest material exhibiting this characteristic, the effect of the light-emitting mechanism according to one embodiment of the present invention becomes particularly pronounced.

[0079] However, the transition energy calculated from the absorption edge in the absorption spectrum of guest material 131 Gee (ΔE abs As ) decreases, the energy of the luminescence exhibited by guest material 131 (ΔE Em ) also becomes smaller, so it is possible to obtain light with high energy, such as blue light. It becomes difficult to do so. That is, ΔE abs and ΔE G If the difference becomes too large This makes it difficult to obtain high-energy light, such as blue light.

[0080] From these observations, the energy difference between the LUMO level and the HOMO level of guest material 131 is... (ΔE G ) is the transition edge calculated from the absorption edge in the absorption spectrum of guest material 131. Energy (ΔE abs Preferably, it is greater than 0.3 eV or more and 0.8 eV or less. It is more preferable that the value is greater than or equal to 0.4 eV or more and 0.8 eV or more. It is even more preferable if it is greater than the range below eV. Also, the emission exhibited by the guest material 131 Energy (ΔE Em ) is ΔE abs It is equivalent to or smaller than that, so guest material 13 The energy difference (ΔE) between the LUMO level and the HOMO level of level 1 G ) is presented by guest material 131 The energy of the light emitted (ΔE Em ) is greater than the range of 0.3eV to 0.8eV. Preferably, it is in the range of 0.4eV to 0.8eV, and more preferably it is greater than 0.5eV. It is even more preferable if it is greater than or equal to 0.8 eV.

[0081] Furthermore, the LUMO level of guest material 131 is lower than that of host material 132. Therefore, the guest material 131 functions as an electron trap in the light-emitting layer 130. When guest material 131 functions as an electron trap, it balances the carriers in the light-emitting layer. This is preferable because it allows for easy control and results in a longer lifespan. On the other hand, guest If the LUMO level of material 131 is too low, the above ΔE B It becomes smaller. This refers to the energy between the LUMO levels of guest material 131 and host material 132. The ghee difference is preferably 0.05 eV to 0.4 eV. Also, the HO of guest material 131 The energy difference between the MO level and the HOMO level of the host material 132 is preferably 0.05 eV or greater, more preferably 0.1 eV or greater, and even more preferably 0.2 eV or less. This is because it makes it easier for hole carriers to be injected into the host material 132. It is suitable.

[0082] Furthermore, the energy difference (ΔE) between the LUMO level and the HOMO level of the host material 132 H )teeth The energy difference (ΔE) between the LUMO level and the HOMO level of guest material 131. G Smaller than Therefore, the carriers (holes and electrons) injected into the light-emitting layer 130 recombine to form excitation As an initial state, the excited state formed by the host material 132 is more energetically stable. Therefore, in addition to the excited state generated by direct carrier coupling in the light-emitting layer 130, Almost all of it exists as an excited state formed by the host material 132. According to one aspect of the present invention, the excitation energy from the host material 132 to the guest material 131 By making energy transfer easier, the driving voltage of the light-emitting element can be reduced, and light emission can be reduced. It can increase efficiency.

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

[0084] By configuring the light-emitting layer 130 as described above, the light emitted from the guest material 131 of the light-emitting layer 130 is achieved. It can be obtained efficiently.

[0085] <Energy transfer mechanism> Next, the control of the intermolecular energy transfer process between the host material 132 and the guest material 131. Let's explain the factors. The mechanism of energy transfer between molecules is the Förster mechanism (bi Two mechanisms have been proposed: the polar-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, and the host Energy transfer occurs through the resonance phenomenon of dipole vibrations between material 132 and guest material 131. This is due to the resonance phenomenon of dipole oscillation, which transfers energy from the host material 132 to the guest material 131. The excited host material 132 returns to the ground state, and the guest material 13 returns to the ground state. 1 becomes an excited state. Note that the rate constant k of the Förster mechanism h*→g This is shown in equation (1). .

[0087]

number

[0088] In equation (1), ν represents the frequency, and f' h (ν) is a standard for host material 132. Emission spectra (when discussing energy transfer from singlet excited states, fluorescence spectra are used) When discussing energy transfer from triplet excited states, the phosphorescent spectrum is used. ε g (ν) represents the molar extinction coefficient of guest material 131, N represents Avogadro's number, and n R represents the refractive index of the medium, and R represents the intermolecular distance between the host material 132 and the guest material 131. τ represents the measured lifetime of the excited state (fluorescence lifetime or phosphorescence lifetime), and c represents the speed of light. φ is the emission quantum yield (when discussing energy transfer from singlet excited states, this refers to the fluorescence quantum yield). The rate (or phosphorescent quantum yield when discussing energy transfer from triplet excited states) is expressed as K. 2 teeth , a coefficient representing the orientation of the transition dipole moments of the host material 132 and the guest material 131 (0 or 4) is the case. Note that 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 come into contact with each other to create an orbital overlap. Approaching within effective contact distance, electrons from the excited host material 132 and the ground state guest material 13 Energy transfer occurs through the exchange of electrons with 1. Note that the rate constant k of the Dexter mechanism. h*→g This 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. Here, ν represents the frequency, and f' h (ν) is the normalized luminescence of the host material 132. Pectol (When discussing energy transfer from singlet excited states, use fluorescence spectra, triplet When discussing energy transfer from an excited state, the phosphorescent spectrum is represented, and ε' g (ν) The normalized absorption spectrum of guest material 131 is shown, and 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 is shown. ET is, number It is expressed by equation (3). k r This is the luminescence process of the host material 132 (energy from singlet excited state When discussing energy transfer, use fluorescence; when discussing energy transfer from triplet excited states, use phosphorus. This represents the velocity constant of light, k n This is the non-luminescent process of the host material 132 (thermal deactivation and intersystem crossing). The rate constant is represented, 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 In order to increase the speed of energy transfer degree constant k h*→g Increase the other competing rate constants k r +k n (=1 / τ) You'll understand that it's better if it's smaller.

[0095] ≪A concept for enhancing energy transfer≫ In energy transfer by the Förster mechanism, the energy transfer efficiency φ ET is, The photon quantum yield φ (when discussing energy transfer from singlet excited states, the fluorescence quantum yield) When discussing energy transfer from triplet excited states, a higher phosphorescence quantum yield is preferable. Furthermore, the emission spectrum of host material 132 (to discuss energy transfer from singlet excited state) (In this case, fluorescence spectrum) and absorption spectrum of guest material 131 (from singlet ground state to triplet) It is preferable that there is a large overlap with the absorption corresponding to the transition to the excited state. It is preferable that the molar extinction coefficient of the host material 131 is also high. This is because the light emission of the host material 132 This means that the spectrum and the absorption band that appears at the longest wavelength end of guest material 131 overlap. ru.

[0096] Furthermore, in energy transfer by the Dexter mechanism, the rate constant k h*→g Make it bigger To do this, we need to consider the emission spectrum of the host material 132 (to discuss energy transfer from the singlet excited state). When discussing the fluorescence spectrum, use the fluorescence spectrum; when discussing energy transfer from the triplet excited state, use the phosphorescence spectrum. Absorption spectra of the culvert and guest material 131 (from singlet ground state to triplet excited state) A larger overlap with the absorption corresponding to the transition is desirable. Therefore, the energy transfer efficiency The optimization involves comparing the emission spectrum of the host material 132 with that of the guest material 131, specifically focusing on the longest wavelength side. This is achieved by the overlap of the absorption bands.

[0097] <Example of light-emitting element configuration 2> Next, regarding a light-emitting element having a configuration different from that shown in Figures 1(A) and 1(B), see Figure 3(A Using (B), the following explanation will be provided.

[0098] Figure 3(A) is a schematic cross-sectional view of a light-emitting element 152 according to one embodiment of the present invention. In the above, the same hatch pattern is used in the parts that have the same function as the symbols shown in Figure 1(A). The symbol may be omitted. Also, the same symbol is used for parts with similar functions. And sometimes, detailed explanations are omitted.

[0099] The light-emitting element 152 has a pair of electrodes (electrode 101 and electrode 102), and between the pair of electrodes It has an EL layer 100 provided therein. The EL layer 100 has at least an emissive layer 135. .

[0100] Figure 3(B) is a schematic cross-sectional view showing an example of the light-emitting layer 135 shown in Figure 3(A). The light-emitting layer 135 shown in B) comprises at least a guest material 131, a host material 132, and a host It has material 133.

[0101] Furthermore, in the light-emitting layer 135, the host material 132 or host material 133 is the most... There are many of them, and guest material 131 is dispersed among host material 132 and host material 133. It can be done.

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

[0103] In one embodiment of the present invention, the light-emitting element 152 also has a pair of electrodes (electrode 101 and electrode 102 The holes and electrons injected from ) recombine, thereby creating the light-emitting layer of the EL layer 100. The guest material 131 within 135 becomes excited, and light is emitted from the excited guest material 131. It can be obtained.

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

[0105] Regarding the (α) direct recombination process, the direct recombination process described in the light emission mechanism of the light emission layer 130 above is explained. Since this process is similar to the recombination process, we will omit the explanation here.

[0106] ≪(β) Energy Transfer Process≫ The energy transfer process of host material 132, host material 133, and guest material 131 To illustrate this, Figure 4(A) shows a schematic diagram illustrating the correlation of energy levels. The notation and symbols in 4(A) are as follows; for other notations and symbols, see Figure This is the same as 2(A). • Host(133): Host material 133 ·S A : S1 level of host material 133 ·T A : T1 level of host material 133

[0107] The carriers recombine in the host material 132, leading to the singlet excited state of the host material 132. And when a triplet excited state is formed, as shown in routes E1 and E2 in Figure 4(A) Thus, both the singlet excitation energy and the triplet excitation energy of the host material 132 are, Singlet excitation energy levels of host material 132 (S H ) and triplet excitation energy levels ( T H ) from the triplet excitation energy level (T G ) move to guest materials Material 131 enters a triplet excited state. The guest material 131 in the triplet excited state emits phosphorescence. Light emission is obtained.

[0108] Furthermore, the excitation energy is efficiently transferred from the host material 132 to the guest material 131. To achieve this, the triplet excitation energy level (T) of the host material 133 is required. A ) but host material 132 The triplet excitation energy level (T H It is preferable that it is higher than ) the host material Quenching of the triplet excitation energy of material 132 becomes less likely, and the guest material 13 Energy transfer occurs to point 1.

[0109] Furthermore, as shown in the energy band diagram in Figure 4(B), the LUMO level of guest material 131 When the level is lower than the LUMO level of the host material 132, as described in the light emission mechanism 1 of the light-emitting element above. As shown above, the energy difference (ΔE) between the LUMO level and the HOMO level of guest material 131 G ) This is the energy difference (ΔE) between the LUMO level and the HOMO level of the host material 132. H Larger than ) It is preferable to use ΔE H This is the LUMO level of guest material 131 and the host material 132 Energy difference (ΔE) from the HOMO level B A larger value is preferable.

[0110] Furthermore, the HOMO level of host material 133 is lower than that of host material 132. Furthermore, the LUMO level of the host material 133 is higher than the LUMO level of the guest material 131. This is preferable. That is, the energy between the LUMO level and the HOMO level of the host material 133 The difference is the difference between the LUMO level of guest material 131 and the HOMO level of host material 132. Energy difference (ΔE B ) is larger. By doing so, host material 133 and host material 13 Reaction to form an excited complex with 2, and reaction between host material 133 and guest material 131 The reaction that forms can be suppressed. Note that in Figure 4(B), Host(13 3) represents the host material 133, and the other notations and symbols are the same as in Figure 2(B).

[0111] Furthermore, the difference between the HOMO levels of host material 133 and host material 132, and The difference between the LUMO levels of host material 133 and guest material 131 is Preferably, it is 0.1 eV or higher, and more preferably 0.2 eV or higher. Having an energy difference, the injection from a pair of electrodes (electrode 101 and electrode 102) The electron carriers and hole carriers are located in the guest material 131 and the host material 132, respectively. It is preferable because it is easily injected into the substance.

[0112] Furthermore, the HOMO level of host material 133 is higher than that of guest material 131. It can be low or even low, and the LUMO level of host material 133 is the same as the LUMO level of host material 132. It can be higher or lower than the level.

[0113] Furthermore, 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 material 132 H ) is preferable i. At this time, the energy difference (ΔE) between the LUMO level and the HOMO level of the host material 132 is H ) is the energy difference (ΔE) between the LUMO level and the HOMO level of guest material 131. G )Yo Because they are small, the carriers (holes and electrons) injected into the light-emitting layer 135 recombine to form The excited states include the host material 133 and the guest material 131, each excited individually. It is more energetically stable for the host material 132 to form an excited state than for it to form an excited state. Therefore, excitation generated in the light-emitting layer 135 by direct carrier recombination occurs. Most of the states will exist as excited states formed by the host material 132. Therefore, in the light-emitting layer 135 as well, the host material 1 is the same as in the configuration of the light-emitting layer 130 described above. By facilitating the transfer of excitation energy from the excited state 32 to the guest material 131, This allows for a reduction in the driving voltage of the light-emitting element 152, thereby increasing the luminous efficiency.

[0114] Furthermore, in the host material 133, holes and electrons recombine and the host material 133 becomes excited. Even when an initial state is formed, the LUMO level and HOMO level of the host material 133 The energy difference is greater than the energy difference between the LUMO level and the HOMO level of the host material 132. When the energy is large, the excitation energy of the host material 133 is quickly transferred to the host material 132. - It can move. Subsequently, the excitation energy is used for the light emission mechanism of the light emission layer 130. Through a similar process, energy is transferred to guest material 131, Light can be obtained from this. Furthermore, holes and electrons can be regenerated in the host material 133. Considering the possibility of bonding, host material 133, like host material 132, undergoes singlet excitation. Materials with a small energy difference between the energy level and the triplet excitation energy level are preferred. In particular, it is preferable that the material be a thermally activated delayed fluorescence material.

[0115] To efficiently obtain luminescence from guest material 131, singlet excitation of host material 133 is required. Energy level (S A ) is the singlet excitation energy level (S) of the host material 132. H ) That's all. Yes, the triplet excitation energy level (T) of the host material 133. A ) is three of the host material 132 Multiplet excitation energy level (T H ) or more is preferable.

[0116] Furthermore, based on the relationship between the LUMO level and the HOMO level described above, the oxide of the host material 133 The position is higher than the oxidation potential of host material 132, and the reduction potential of host material 133 is G It is preferable that the reduction potential is lower than that of material 131.

[0117] Furthermore, the combination of host material 132 and host material 133 provides a function for transporting holes. In the case of a combination of a material that has the function of transporting electrons and a material that has the function of transporting electrons, the mixing ratio Therefore, it becomes possible to easily control the carrier balance. Specifically, transporting holes Materials with the function of transporting electrons: Materials with the function of transporting electrons = 1:9 to 9:1 (by weight) A range is preferred. Furthermore, having this configuration allows for easy control of the carrier balance. Because this is possible, the carrier recombination region can also be easily controlled.

[0118] By configuring the light-emitting layer 135 as described above, the light emitted from the guest material 131 of the light-emitting layer 135 is achieved. It can be obtained efficiently.

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

[0120] ≪Luminous layer≫ In the light-emitting layer 130 and the light-emitting layer 135, the host material 132 contains at least the guest material 1 It is present in greater proportion by weight than 31, and guest material 131 (phosphorescent material) is present in host material 132. It will be distributed.

[0121] ≪Host Material 132≫ The energy difference between the S1 level and the T1 level of the host material 132 is preferably small. Physically, it is greater than 0 eV and less than or equal to 0.2 eV.

[0122] The host material 132 has a hole-transporting skeleton and an electron-transporting skeleton. It is preferable that the host material 132 has a π-electron-rich heteroaromatic ring skeleton or It is preferable to have an aromatic amine skeleton and a π-electron-deficient heteroaromatic ring skeleton. This makes it easier to form donor-acceptor type excited states within the molecule. Furthermore, In the molecule of material 132, both donor and acceptor properties are strengthened, and electron transport properties are developed. It is preferable to have a structure in which a skeleton having a function and a skeleton having hole transport capabilities are directly bonded together. Alternatively, a π-electron-rich heterochromatic aromatic ring skeleton or aromatic amine skeleton and a π-electron-deficient heterochromatic It is preferable that the aromatic ring skeleton has a structure in which it is directly bonded. Intramolecular donor and accept By strengthening both properties, the molecular orbitals in the HOMO of the host material 132 are distributed. The overlap between the region and the region where molecular orbitals are distributed in the LUMO can be reduced. The energy difference between the singlet excitation energy level and the triplet excitation energy level of the host material 132 - This makes it possible to reduce the difference. Also, the triplet excitation energy level of the host material 132 This makes it possible to maintain a high energy level.

[0123] Materials with a small energy difference between the singlet excitation energy level and the triplet excitation energy level. Examples include thermally activated delayed fluorescence materials. Note that thermally activated delayed fluorescence materials are triplet fluorescence materials. Because the difference between the excitation energy level and the singlet excitation 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 a singlet excited state with only a small amount of thermal energy. It allows for reverse intersystem crossing (BART) and efficiently exhibits luminescence (fluorescence) from the singlet excited state. This can be achieved. Furthermore, conditions under which thermally activated delayed fluorescence can be efficiently obtained include triplet excitation energy. The energy difference between the energy level and the singlet excitation energy level is preferably greater than 0 eV. The voltage is 0.2 eV or less, and more preferably greater than 0 eV and 0.1 eV or less. It can be done.

[0124] When a thermally activated delayed fluorescence material is composed of only one type of material, for example, the following materials can be used. It is possible.

[0125] First, there are fullerenes and their derivatives, acridine derivatives such as proflavin, and eosin. It can be produced. Also, magnesium (Mg), zinc (Zn), cadmium (Cd), tin (S) n) Metals containing platinum (Pt), indium (In), or palladium (Pd), etc. Examples include metal-containing porphyrins. For example, protoporph Fluorine-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)), Ethioporphyrin-tin fluoride complex (SnF2(E Examples include tio I)) and octaethylporphyrin-platinum chloride complex (PtCl2OEP). It can be done.

[0126] [ka]

[0127] Furthermore, as a thermally activated delayed fluorescence material composed of one type of material, a π-electron-rich complex atom is an example. Heterocyclic compounds having aromatic rings and π-electron-deficient heteroaromatic rings can also be used. Specifically is 2-(biphenyl-4-yl)-4,6-bis(12-phenylindoro[2,3- a)Carbazole-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol [9-yl]phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: PC) CzPTzn), 2-[4-(10H-phenoxazine-10-yl)phenyl]-4, 6-Diphenyl-1,3,5-triazine (abbreviation: PXZ-TRZ), 3-[4-(5- Phenyl-5,10-dihydrophenazine-10-yl)phenyl]-4,5-diphenyl Lu-1,2,4-triazole (abbreviation: 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] Examples include -9,9'-anthracene]-10'-one (abbreviated as ACRSA). Because the cyclic compounds have π-electron-rich heteroaromatic rings and π-electron-deficient heteroaromatic rings, High transportability and hole transportability are desirable. In particular, a skeleton having a π-electron-deficient heteroaromatic ring is preferred. Among them, the diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton), and the tori The azine skeleton is preferred because it is stable and reliable. Furthermore, it possesses a π-electron-rich heteroaromatic ring. Among the skeletons, there are acridine skeletons, phenoxazine skeletons, phenothiazine skeletons, and furan skeletons. The skeleton, thiophene skeleton, and pyrrole skeleton are stable and reliable, therefore, small amounts of these skeletons are used. It is preferable to have at least one. Furthermore, the dibenzofuran skeleton is preferred as the furan skeleton. Dibenzothiophene skeletons are preferred as the thiophene skeletons. The skeleton consists of an indole skeleton, a carbazole skeleton, and 9-phenyl-3,3'-be- A 9H-carbazole skeleton is particularly preferred. Note that π-electron-rich heteroaromatic rings and π-electron-deficient rings are also preferred. Substances directly bonded to a type of heteroaromatic ring exhibit both donor and π-electron-deficient properties for π-electron-rich heteroaromatic rings. Both types of complex aromatic rings have strong acceptor properties, and the singlet excited state level and the triplet excited state level This is particularly preferable because the difference in positions becomes smaller. Furthermore, instead of a π-electron-deficient heteroaromatic ring, Aromatic rings with electron-withdrawing groups, such as the Ano group, can also be used.

[0128] [ka]

[0129] Furthermore, as a skeleton having a π-electron-deficient heteroaromatic ring, a condensed complex having a diazine skeleton A ring skeleton is preferred because it is more stable and reliable, and among them, the benzoflopyrimidine skeleton is preferred. The benzothienopyrimidine skeleton is particularly preferred due to its high acceptor properties. An example of a lopyrimidine skeleton is the benzoflo[3,2-d]pyrimidine skeleton. Furthermore, as a benzothienopyrimidine skeleton, for example, benzothieno[3,2-d] One example is the pyrimidine skeleton.

[0130] As a skeleton having a π-electron-rich heteroaromatic ring, the bicarbazole skeleton has an excitation energy - is preferable because it is high, stable and reliable. For example, the bicarbazole skeleton is 2 Bicarbazole bone in which two carbazolyl groups are bonded to each other at any of the positions from 1 to 4. The grade is particularly preferred due to its high donor potential. For example, the bicarbazole skeleton is 2 ,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'- Examples include the bi-9H-carbazole skeleton and the 3,4'-bi-9H-carbazole skeleton. .

[0131] Furthermore, from the perspective of widening the band gap and increasing the triplet excitation energy, The 9th position of one of the carbazolyl groups in the bicarbazole skeleton directly benzoflopyrimid Compounds bonded to a benzothienopyrimidine skeleton or a benzothienopyrimidine skeleton are preferred. The carbazole skeleton and the benzoflopyrimidine skeleton or benzothienopyrimidine skeleton When directly bonded, it results in a relatively low molecular weight compound, making it suitable for vacuum deposition (at relatively low temperatures). This structure is preferable as it allows for vacuum deposition. Generally, a lower molecular weight results in better heat resistance after film formation. Although the properties are often low, the benzoflopyrimidine skeleton, benzothienopyrimidine skeleton, Furthermore, because the bicarbazole skeleton is a rigid skeleton, compounds having this skeleton have a relative molecular weight. It is possible to have sufficient heat resistance even at a relatively low temperature. Furthermore, this structure has band gaps This is preferable because it increases the pulse level and raises the excitation energy level.

[0132] Furthermore, the bicarbazole skeleton and the benzoflopyrimidine skeleton or benzothienopyrimidine In cases where the skeleton and the arylene group are bonded via an arylene group, the number of carbon atoms in the arylene group 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 compound has a relatively low molecular weight. Therefore, it becomes a structure suitable for vacuum deposition (vacuum deposition can be performed at relatively low temperatures).

[0133] Furthermore, the bicarbazole skeleton is directly or via the arylene group, benzofloxacin [3,2 -d] Binds to the pyrimidine skeleton or the benzothieno[3,2-d]pyrimidine skeleton, Preferably, a benzoflo[3,2-d]pyrimidine skeleton or benzothieno[3,2- [d] By binding to the 4-position of the pyrimidine skeleton, the compound exhibits excellent carrier transport properties. Therefore, a light-emitting element using this compound can be driven at a low voltage. ru.

[0134] ≪Example of a compound 1≫ A 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 found in other compounds.

[0135] [ka]

[0136] In the above general formula (G0), A is a substituted or unsubstituted benzoflopyrimidine skeleton. , or represents the benzothienopyrimidine skeleton. The benzophropyrimidine skeleton or ben If the zothienopyrimidine skeleton has substituents, such substituents may have 1 to 6 carbon atoms. Alkyl groups, cycloalkyl groups with 3 to 7 carbon atoms, or substituted or unsubstituted carbon-6 atoms. Aryl groups of up to 13 carbon atoms can also be selected as substituents. Alkyl groups having 1 to 6 carbon atoms. Specifically, the groups include methyl group, ethyl group, propyl group, isopropyl group, and butyl group. Examples include isobutyl groups, tert-butyl groups, and n-hexyl groups. Specifically, examples of cycloalkyl groups having 3 to 7 carbon atoms include cyclopropyl groups and cyclopropyl groups. Examples include cyclopentyl groups, cyclopentyl groups, and cyclohexyl groups. Also, the number of carbon atoms The aryl groups 6 to 13 include phenyl, naphthyl, biphenyl, and fluorenyl groups. The 'L' group can be given as a specific example.

[0137] Also, R 1 ~R 15 Each of these independently consists of hydrogen, substituted or unsubstituted carbon atoms with 1 or more carbon atoms. 6 alkyl groups, substituted or unsubstituted cycloalkyl groups having 3 to 7 carbon atoms, or substituted groups. Alternatively, it represents any of the unsubstituted aryl groups with 6 to 13 carbon atoms. Specifically, propyl groups include methyl, ethyl, propyl, isopropyl, and butyric groups. Examples include the 1xyl group, isobutyl group, tert-butyl group, and n-hexyl group. Furthermore, specific examples of cycloalkyl groups having 3 to 7 carbon atoms include cyclopropyl groups, cyclopropyl groups, and cyclopropyl groups. Examples include chlorobutyl groups, cyclopentyl groups, and cyclohexyl groups. Examples of aryl groups having 6 to 13 carbon atoms include phenyl, naphthyl, biphenyl, and flu. The olen group can be given as a specific example. Furthermore, the alkyl and cyclic groups mentioned above... The R-alkyl group and the aryl group may have substituents, and these substituents are bonded to each other. A ring may be formed. The substituent may be an alkyl group having 1 to 6 carbon atoms, or a ring having 3 carbon atoms. A cycloalkyl group with up to 7 carbon atoms, or an aryl group with 6 to 13 carbon atoms, can also be selected as a substituent. This is possible. Specifically, alkyl groups having 1 to 6 carbon atoms include methyl groups, ethyl groups, Propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, n-hex Examples include syl groups. In addition, cycloalkyl groups having 3 to 7 carbon atoms can be used. In terms of composition, it consists of cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl groups. Examples include the phenyl group. Naphthyl groups, biphenyl groups, and fluorenyl groups are some specific examples.

[0138] Also, Ar 1 This represents an arylene group or single bond having 6 to 25 carbon atoms, and the arylene The n group may have substituents, and these substituents may bond to each other to form a ring. For example, the carbon at position 9 of the fluorenyl group has a phenyl group as a substituent. It has two such phenyl groups, and these phenyl groups bond together to form a spirofluorene skeleton. Examples include the following cases. As for arylene groups having 6 to 25 carbon atoms, phenylene groups, Examples include naphthylene groups, biphenyldiyl groups, and fluoranyl groups. This can be done. Furthermore, if the arylene group has substituents, the substituents may be defined as having a carbon number. 1 to 6 alkyl groups, 3 to 7 cycloalkyl groups, or 6 to 13 C groups Aryl groups can also be selected as substituents. C1 to C6 alkyl groups include Specifically, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl Examples include the tert-butyl group, n-hexyl group, etc. Also, the 3-carbon group Specifically, the cycloalkyl groups up to 7 include cyclopropyl group, cyclobutyl group, and cyclopropyl group. Examples include lopentyl groups and cyclohexyl groups. Also, groups with 6 to 13 carbon atoms. Examples of aryl groups include phenyl, naphthyl, biphenyl, and fluorenyl groups. This can be cited as an example.

[0139] Furthermore, in the compound represented by the general formula (G0), the benzophropyrimidine skeleton is ben It is preferable that the skeleton be zoflo[3,2-d]pyrimidine. Also, benzothienopyrimidine. The skeleton is preferably a benzothieno[3,2-d]pyrimidine skeleton.

[0140] Furthermore, in compounds represented by the general formula (G0), one of the carba of the bicarbazole skeleton At position 9 of the zolyl group, directly or via the arylene group, benzoflo[3,2-d] The 4th position of the pyrimidine skeleton or the benzothieno[3,2-d]pyrimidine skeleton, and the bonded structure Compounds possessing this property exhibit both strong donor and acceptor properties and have a broad band gap. Therefore, it can be suitably used in light-emitting elements that exhibit high-energy light, such as blue light. This is a preferred configuration. The above compound is a compound represented by the following general formula (G1).

[0141] [ka]

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

[0143] Also, R 1 ~R 20 Each of these independently consists of hydrogen, substituted or unsubstituted carbon atoms with 1 or more carbon atoms. 6 alkyl groups, substituted or unsubstituted cycloalkyl groups having 3 to 7 carbon atoms, or substituted groups. Alternatively, it represents any of the unsubstituted aryl groups with 6 to 13 carbon atoms. Specifically, propyl groups include methyl, ethyl, propyl, isopropyl, and butyric groups. Examples include the 1xyl group, isobutyl group, tert-butyl group, and n-hexyl group. Furthermore, specific examples of cycloalkyl groups having 3 to 7 carbon atoms include cyclopropyl groups, cyclopropyl groups, and cyclopropyl groups. Examples include chlorobutyl groups, cyclopentyl groups, and cyclohexyl groups. Examples of aryl groups having 6 to 13 carbon atoms include phenyl, naphthyl, biphenyl, and flu. The olen group can be given as a specific example. Furthermore, the alkyl and cyclic groups mentioned above... The R-alkyl group and the aryl group may have substituents, and these substituents are bonded to each other. A ring may be formed. The substituent may be an alkyl group having 1 to 6 carbon atoms, or a ring having 3 carbon atoms. A cycloalkyl group with up to 7 carbon atoms, or an aryl group with 6 to 13 carbon atoms, can also be selected as a substituent. This is possible. Specifically, alkyl groups having 1 to 6 carbon atoms include methyl groups, ethyl groups, Propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, n-hex Examples include syl groups. In addition, cycloalkyl groups having 3 to 7 carbon atoms can be used. In terms of composition, it consists of cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl groups. Examples include the phenyl group. Naphthyl groups, biphenyl groups, and fluorenyl groups are some specific examples.

[0144] Also, Ar 1 This represents an arylene group or single bond having 6 to 25 carbon atoms, and the arylene The n group may have substituents, and these substituents may bond to each other to form a ring. For example, the carbon at position 9 of the fluorenyl group has a phenyl group as a substituent. It has two such phenyl groups, and these phenyl groups bond together to form a spirofluorene skeleton. Examples include the following cases. As for arylene groups having 6 to 25 carbon atoms, phenylene groups, Examples include naphthylene groups, biphenyldiyl groups, and fluoranyl groups. This can be done. Furthermore, if the arylene group has substituents, the substituents may be defined as having a carbon number. 1 to 6 alkyl groups, 3 to 7 cycloalkyl groups, or 6 to 13 C groups Aryl groups can also be selected as substituents. C1 to C6 alkyl groups include Specifically, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl Examples include the tert-butyl group, n-hexyl group, etc. Also, the 3-carbon group Specifically, the cycloalkyl groups up to 7 include cyclopropyl group, cyclobutyl group, and cyclopropyl group. Examples include lopentyl groups and cyclohexyl groups. Also, groups with 6 to 13 carbon atoms. Examples of aryl groups include phenyl, naphthyl, biphenyl, and fluorenyl groups. This can be cited as an example.

[0145] Furthermore, in the compound represented by the 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 position 9, directly or via the arylene group, benzoflo[3,2-d]pyrimidine bone Compounds having a structure bonded to the 4th position of the benzothieno[3,2-d]pyrimidine skeleton Because the material has excellent carrier transport properties, light-emitting elements using it can be driven at low voltages. This is a preferred configuration. The above compound is a compound represented by the following general formula (G2).

[0146] [ka]

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

[0148] Also, R 1 ~R20 Each of these independently consists of hydrogen, substituted or unsubstituted carbon atoms with 1 or more carbon atoms. 6 alkyl groups, substituted or unsubstituted cycloalkyl groups having 3 to 7 carbon atoms, or substituted groups. Alternatively, it represents any of the unsubstituted aryl groups with 6 to 13 carbon atoms. Specifically, propyl groups include methyl, ethyl, propyl, isopropyl, and butyric groups. Examples include the 1xyl group, isobutyl group, tert-butyl group, and n-hexyl group. Furthermore, specific examples of cycloalkyl groups having 3 to 7 carbon atoms include cyclopropyl groups, cyclopropyl groups, and cyclopropyl groups. Examples include chlorobutyl groups, cyclopentyl groups, and cyclohexyl groups. Examples of aryl groups having 6 to 13 carbon atoms include phenyl, naphthyl, biphenyl, and flu. The olen group can be given as a specific example. Furthermore, the alkyl and cyclic groups mentioned above... The R-alkyl group and the aryl group may have substituents, and these substituents are bonded to each other. A ring may be formed. The substituent may be an alkyl group having 1 to 6 carbon atoms, or a ring having 3 carbon atoms. A cycloalkyl group with up to 7 carbon atoms, or an aryl group with 6 to 13 carbon atoms, can also be selected as a substituent. This is possible. Specifically, alkyl groups having 1 to 6 carbon atoms include methyl groups, ethyl groups, Propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, n-hex Examples include syl groups. In addition, cycloalkyl groups having 3 to 7 carbon atoms can be used. In terms of composition, it consists of cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl groups. Examples include the phenyl group. Naphthyl groups, biphenyl groups, and fluorenyl groups are some specific examples.

[0149] Also, Ar 1This represents an arylene group or single bond having 6 to 25 carbon atoms, and the arylene The n group may have substituents, and these substituents may bond to each other to form a ring. For example, the carbon at position 9 of the fluorenyl group has a phenyl group as a substituent. It has two such phenyl groups, and these phenyl groups bond together to form a spirofluorene skeleton. Examples include the following cases. As for arylene groups having 6 to 13 carbon atoms, phenylene groups, Examples include naphthylene groups, biphenyldiyl groups, and fluoranyl groups. This can be done. Furthermore, if the arylene group has substituents, the substituents may be defined as having a carbon number. 1 to 6 alkyl groups, 3 to 7 cycloalkyl groups, or 6 to 13 C groups Aryl groups can also be selected as substituents. C1 to C6 alkyl groups include Specifically, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl Examples include the tert-butyl group, n-hexyl group, etc. Also, the 3-carbon group Specifically, the cycloalkyl groups up to 7 include cyclopropyl group, cyclobutyl group, and cyclopropyl group. Examples include lopentyl groups and cyclohexyl groups. Also, groups with 6 to 13 carbon atoms. Examples of aryl groups include phenyl, naphthyl, biphenyl, and fluorenyl groups. This can be cited as an example.

[0150] Furthermore, in compounds represented by general formula (G1) or (G2), the bicarbazole skeleton This structure involves direct bonding between the benzoflopyrimidine skeleton or the benzothienopyrimidine skeleton. When it contains the necessary components, the band gap is improved, and synthesis with high purity becomes possible. Therefore, it is a desirable configuration. Furthermore, since the compound has excellent carrier transport properties, it can be used These light-emitting elements can be driven at low voltage.

[0151] Furthermore, in the above general formula (G1) or (G2), R 1 ~R 14 , and R 16 ~ R 20 However, if it is all hydrogen, it is advantageous in terms of ease of synthesis and the price of raw materials, and further Furthermore, because it results in a compound with a relatively low molecular weight, it has a structure suitable for vacuum deposition, which is particularly preferable. The compound in question is represented by the following general formula (G3) or general formula (G4).

[0152] [ka]

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

[0154] Also, R 15 This includes hydrogen, substituted or unsubstituted C1-C6 alkyl groups, and substituted or or an unsubstituted cycloalkyl group having 3 to 7 carbon atoms, or a substituted or unsubstituted cycloalkyl group having 6 carbon atoms. It represents any of the aryl groups from 1 to 13. Specifically, alkyl groups having 1 to 6 carbon atoms are... methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, te Examples include rt-butyl groups and n-hexyl groups. Also, groups with 3 to 7 carbon atoms. Specifically, examples of cloalkyl groups include cyclopropyl group, cyclobutyl group, and cyclopene group. Examples include tyl groups and cyclohexyl groups. Also, ally groups with 6 to 13 carbon atoms. Examples of fluorenyl groups include phenyl, naphthyl, biphenyl, and fluorenyl groups. These can be listed as follows. Furthermore, the alkyl groups, cycloalkyl groups, and aryl groups mentioned above. The group may have substituents, and these substituents may bond to each other to form a ring. The substituents include alkyl groups having 1 to 6 carbon atoms, cycloalkyl groups having 3 to 7 carbon atoms, Alternatively, aryl groups having 6 to 13 carbon atoms can also be selected as substituents. Specifically, alkyl groups up to 6 include methyl group, ethyl group, propyl group, and isopropyl group. Examples include the butyl group, isobutyl group, tert-butyl group, and n-hexyl group. Yes, it is possible. Specifically, examples of cycloalkyl groups with 3 to 7 carbon atoms include cyclopropyl Examples include the cyclobutyl group, cyclopentyl group, and cyclohexyl group. Furthermore, aryl groups having 6 to 13 carbon atoms include phenyl groups, naphthyl groups, and biphenyl groups. Fluorenyl groups can be given as specific examples.

[0155] Also, Ar 1 This represents an arylene group or single bond having 6 to 25 carbon atoms, and the arylene The n group may have substituents, and these substituents may bond to each other to form a ring. For example, the carbon at position 9 of the fluorenyl group has a phenyl group as a substituent. It has two such phenyl groups, and these phenyl groups bond together to form a spirofluorene skeleton. Examples include the following cases. As for arylene groups having 6 to 25 carbon atoms, phenylene groups, Examples include naphthylene groups, biphenyldiyl groups, and fluoranyl groups. This can be done. Furthermore, if the arylene group has substituents, the substituents may be defined as having a carbon number. 1 to 6 alkyl groups, 3 to 7 cycloalkyl groups, or 6 to 13 C groups Aryl groups can also be selected as substituents. C1 to C6 alkyl groups include Specifically, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl Examples include the tert-butyl group, n-hexyl group, etc. Also, the 3-carbon group Specifically, the cycloalkyl groups up to 7 include cyclopropyl group, cyclobutyl group, and cyclopropyl group. Examples include lopentyl groups and cyclohexyl groups. Also, groups with 6 to 13 carbon atoms. Examples of aryl groups include phenyl, naphthyl, biphenyl, and fluorenyl groups. This can be cited as an example.

[0156] [ka]

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

[0158] Also, R 15 This includes hydrogen, substituted or unsubstituted C1-C6 alkyl groups, and substituted or or an unsubstituted cycloalkyl group having 3 to 7 carbon atoms, or a substituted or unsubstituted cycloalkyl group having 6 carbon atoms. It represents any of the aryl groups from 1 to 13. Specifically, alkyl groups having 1 to 6 carbon atoms are... methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, te Examples include rt-butyl groups and n-hexyl groups. Also, groups with 3 to 7 carbon atoms. Specifically, examples of cloalkyl groups include cyclopropyl group, cyclobutyl group, and cyclopene group. Examples include tyl groups and cyclohexyl groups. Also, ally groups with 6 to 13 carbon atoms. Examples of fluorenyl groups include phenyl, naphthyl, biphenyl, and fluorenyl groups. These can be listed as follows. Furthermore, the alkyl groups, cycloalkyl groups, and aryl groups mentioned above. The group may have substituents, and these substituents may bond to each other to form a ring. The substituents include alkyl groups having 1 to 6 carbon atoms, cycloalkyl groups having 3 to 7 carbon atoms, Alternatively, aryl groups having 6 to 13 carbon atoms can also be selected as substituents. Specifically, alkyl groups up to 6 include methyl group, ethyl group, propyl group, and isopropyl group. Examples include the butyl group, isobutyl group, tert-butyl group, and n-hexyl group. Yes, it is possible. Specifically, examples of cycloalkyl groups with 3 to 7 carbon atoms include cyclopropyl Examples include the cyclobutyl group, cyclopentyl group, and cyclohexyl group. Furthermore, aryl groups having 6 to 13 carbon atoms include phenyl groups, naphthyl groups, and biphenyl groups. Fluorenyl groups can be given as specific examples.

[0159] Also, Ar 1 This represents an arylene group or single bond having 6 to 25 carbon atoms, and the arylene The n group may have substituents, and these substituents may bond to each other to form a ring. For example, the carbon at position 9 of the fluorenyl group has a phenyl group as a substituent. It has two such phenyl groups, and these phenyl groups bond together to form a spirofluorene skeleton. Examples include the following cases. As for arylene groups having 6 to 25 carbon atoms, phenylene groups, Examples include naphthylene groups, biphenyldiyl groups, and fluoranyl groups. This can be done. Furthermore, if the arylene group has substituents, the substituents may be defined as having a carbon number. 1 to 6 alkyl groups, 3 to 7 cycloalkyl groups, or 6 to 13 C groups Aryl groups can also be selected as substituents. C1 to C6 alkyl groups include Specifically, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl Examples include the tert-butyl group, n-hexyl group, etc. Also, the 3-carbon group Specifically, the cycloalkyl groups up to 7 include cyclopropyl group, cyclobutyl group, and cyclopropyl group. Examples include lopentyl groups and cyclohexyl groups. Also, groups with 6 to 13 carbon atoms. Examples of aryl groups include phenyl, naphthyl, biphenyl, and fluorenyl groups. This can be cited as an example.

[0160] In the general formula (G0), the benzophropyrimidine skeleton or benzothophyll is represented as A. For example, the enopyrimidine skeleton is represented by the following structural formulas (Ht-1) to (Ht-24). The structure can be applied. Note that the structures that can be used as A are these It is not limited to that.

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[0163] In the above structural formulas (Ht-1) to (Ht-24), R 16 ~R 20 These are, Independently, hydrogen, substituted or unsubstituted C1 to C6 alkyl groups, 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. It represents any of the aryl groups. Specifically, alkyl groups having 1 to 6 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl Examples include cycloalkyl groups and n-hexyl groups. Also, cycloalkyl groups having 3 to 7 carbon atoms. Specifically, the cyclopropyl group includes cyclopropyl group, cyclobutyl group, cyclopentyl group, and cyclopropyl group. Examples include chlorohexyl groups. Also, as aryl groups having 6 to 13 carbon atoms... Examples include phenyl groups, naphthyl groups, biphenyl groups, and fluorenyl groups. Furthermore, the alkyl, cycloalkyl, and aryl groups mentioned above can be substituted. The substituents may have groups, and the substituents may bond to each other to form a ring. For example, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms, or carbon Aryl groups with 6 to 13 carbon atoms can also be selected as substituents. Specifically, methyl, ethyl, propyl, isopropyl, and butyl groups are examples of methyl, ethyl, propyl, isopropyl, and butyl groups. Examples include the isobutyl group, tert-butyl group, and n-hexyl group. Specifically, examples of cycloalkyl groups having 3 to 7 carbon atoms include cyclopropyl groups and cyclo Examples include butyl groups, cyclopentyl groups, and cyclohexyl groups. Also, carbon Examples of aryl groups numbered 6 to 13 include phenyl, naphthyl, biphenyl, and fluorescein groups. The yl group can be given as a specific example.

[0164] Furthermore, in general formulas (G0) and (G1), it can be used as the bicarbazole skeleton. Possible structures include, for example, structures represented by the following structural formulas (Cz-1) to (Cz-9). This can be applied. Note that the structures that can be used as the bicarbazole skeleton are as follows: It is not limited to these.

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[0167] In the above structural formulas (Cz-1) to (Cz-9), R 1 ~R 15 Each is independent in addition, hydrogen, substituted or unsubstituted C1 to C6 alkyl groups, substituted or unsubstituted carbon Cycloalkyl groups with 3 to 7 prime atoms, or substituted or unsubstituted ali groups with 6 to 13 carbon atoms. It represents any of the alkyl groups. Specifically, alkyl groups having 1 to 6 carbon atoms include the methyl group, Ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group Examples include n-hexyl groups. Also, cycloalkyl groups having 3 to 7 carbon atoms. Specifically, these include cyclopropyl group, cyclobutyl group, cyclopentyl group, and cyclo Examples include hexyl groups. Also, as for aryl groups having 6 to 13 carbon atoms, Examples include phenyl groups, naphthyl groups, biphenyl groups, and fluorenyl groups. This can be achieved. Furthermore, the alkyl, cycloalkyl, and aryl groups mentioned above have substituents. They may have, and the substituents may bond to each other to form a ring. This includes alkyl groups having 1 to 6 carbon atoms, cycloalkyl groups having 3 to 7 carbon atoms, or C6 Aryl groups of up to 13 carbon atoms can also be selected as substituents. Alkyl groups having 1 to 6 carbon atoms. Specifically, the groups include methyl group, ethyl group, propyl group, isopropyl group, and butyl group. Examples include isobutyl groups, tert-butyl groups, and n-hexyl groups. Examples of cycloalkyl groups having 3 to 7 carbon atoms include cyclopropyl group, cyclobutyl group, etc. Examples include the cyclopentyl group, cyclohexyl group, etc. Also, a group with 6 carbon atoms. The aryl groups up to 13 include phenyl, naphthyl, biphenyl, and fluorenyl groups. Examples such as the basics can be given as concrete examples.

[0168] Furthermore, in the above general formulas (G0) to (G4), Ar 1 The arylene group represented by is For example, groups represented by the following structural formulas (Ar-1) to (Ar-27) can be applied. Ar 1 The groups that can be used as such are not limited to these, and include groups having substituents. You can.

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[0171] Furthermore, R in the above general formulas (G1) and (G2) 1 ~R 20 , R of the general formula (G0) 1 ~ R 15 , R of general formulas (G3) and (G4) 15 alkyl groups and cycloalkyl groups represented by , A group, or aryl group, is a group represented by the following structural formulas (R-1) to (R-29). This can be applied. Note that alkyl groups, cycloalkyl groups, or aryl groups may be used. The groups that can be used are not limited to these, and may also have substituents.

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[0173] ≪Specific examples of compounds≫ The specific structures of the compounds represented by the above general formulas (G0) to (G4) are as follows: Examples include compounds represented by structural formulas (100) to (147). Note that general formula (G The compounds represented as 0) through (G4) are not limited to the following examples.

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[0182] ≪Example of a compound 2≫ Furthermore, the host material 132 has singlet excitation energy levels and triplet excitation energy levels The energy difference between them should be small, and it is not necessarily required that the inverse intersystem crossing efficiency be high, The yield does not need to be high, and it does not need to have the function of exhibiting thermally activated delayed fluorescence. The host material 132 has a skeleton having a π-electron-rich heteroaromatic ring or an aromatic amine skeleton. At least one of them and a skeleton having a π-electron-deficient heteroaromatic ring are connected by an m-phenylene group or It is preferable to have a structure that is bonded via a structure having at least one o-phenylene group. It is preferable to bond via a biphenyldiyl group. Alternatively, m - Via an arylene group having at least one phenylene group or an o-phenylene group It is preferable that the structure has a bonding structure, and the arylene group is said to be a biphenyldiyl group. Furthermore, this is preferable. By doing so, the T1 level of the host material 132 can be raised. In this case as well, the skeleton having a π-electron-deficient heteroaromatic ring is a diazine skeleton (pi Limidine skeleton, pyrazine skeleton, pyridazine skeleton, and at least one triazine skeleton It is preferable to have the following characteristics. Furthermore, a skeleton having a π-electron-rich heteroaromatic ring is acridine. Skeleton, phenoxazine skeleton, phenothiazine skeleton, furan skeleton, thiophene skeleton, and pi It is preferable that it has at least one roll skeleton. The furan skeleton is diben. The zofran skeleton is preferred, and the dibenzothiophene skeleton is preferred as the thiophene skeleton. The pyrrole skeletons include the indole skeleton, the carbazole skeleton, and 9-phenyl A -3,3'-bi-9H-carbazole skeleton is particularly preferred. Also, an aromatic amine skeleton and In this regard, so-called tertiary amines that do not have an NH bond are preferred, and triarylamines are particularly preferred. The skeleton is preferred. As for the aryl group of the triarylamine skeleton, the number of carbon atoms forming the ring is preferred. A substituted or unsubstituted aryl group having 6 to 13 carbon atoms is preferred, as are a phenyl group, a naphthyl group, Examples include the fluorenyl group.

[0183] Examples of the above aromatic amine skeleton and skeletons having a π-electron-rich heteroaromatic ring include: The skeleton is represented by the following general formulas (401) to (417). Note that general formula (413) In (416), X represents either an oxygen atom or a sulfur atom.

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[0185] Furthermore, an example of a skeleton having the above-mentioned π-electron-deficient heteroaromatic ring is the following general formula (20 1) The skeleton is represented by (218).

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[0187] Hole-transporting skeletons (specifically, π-electron-rich heteroaromatic ring skeletons or aromatic amines) (at least one of the skeletons) and a skeleton with electron transport properties (specifically, a π-electron-deficient complex aromatic A ring skeleton and a bond having at least one m-phenylene group or an o-phenylene group. When bonding occurs via a group, when bonding occurs via a biphenyldiyl group as a bonding group, It has an arylene group having at least one m-phenylene group or an o-phenylene group. When bonding occurs via a bonding group, an example of such a bonding group is the following general formula (301) to This is the skeleton represented by (315). Note that the above arylene group is the phenylene skeleton. , biphenyldiyl skeleton, naphthalenediyl skeleton, fuloangularyl skeleton, phenanthr Examples include the rudimentary skeleton.

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[0189] The above-mentioned aromatic amine skeleton (specifically, the triarylamine skeleton), π-electron-rich complex Aromatic ring skeletons (specifically acridine skeleton, phenoxazine skeleton, phenothiazine skeleton, f A ring having at least one of the following skeletons: a ranic skeleton, a thiophene skeleton, and a pyrrole skeleton, with π electron deficiency. A type of heteroatomous aromatic ring skeleton (specifically, having at least one of a diazine skeleton and a triazine skeleton) The ring that is formed), or the above general formulas (401) to (417), general formulas (201) to (2 18) and general formulas (301) to (315) may have substituents. The bases include alkyl groups with 1 to 6 carbon atoms and cycloalkyl groups with 3 to 6 carbon atoms. aryl groups, or substituted or unsubstituted aryl groups having 6 to 12 carbon atoms, can also be used as substituents. It can be selected. Specifically, alkyl groups having 1 to 6 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl Examples include cyclo groups and n-hexyl groups. Also, cyclo groups with 3 to 6 carbon atoms. Specifically, alkyl groups include cyclopropyl, cyclobutyl, and cyclopentyl groups. Examples include groups such as the cyclohexyl group. Also, ants with 6 to 12 carbon atoms. Examples of phenyl groups include phenyl, naphthyl, and biphenyl groups. This can be achieved. Furthermore, the substituents may bond to each other to form a ring. An example of this is... For example, the carbon at position 9 in the fluorene skeleton has two phenyl groups as substituents. In this case, the phenyl groups bond together to form a spirofluorene skeleton. Such cases can be cited. Furthermore, in the case of unsubstituted compounds, there are advantages in terms of ease of synthesis and the cost of raw materials. ru.

[0190] Also, Ar 2 This represents an arylene group having 6 to 13 carbon atoms, and the arylene group is They may have substitution groups, and these substituents may bond to each other to form a ring. Examples include... For example, the carbon at position 9 of the fluorenyl group has two phenyl groups as substituents. In a field where the phenyl groups bond together to form a spirofluorene skeleton Examples include arylene groups having 6 to 13 carbon atoms, such as phenylene groups and naphthene groups. Specific examples include the ethylene group, biphenylene group, and fluoroorangeyl group. Furthermore, if the arylene group has substituents, such substituents may be C1 to C1. A 6-C1 alkyl group, a cycloalkyl group with 3 to 6 C1s, or a group with 6 to 6 C1s Aryl groups with 12 carbon atoms can also be selected as substituents. Specifically, methyl, ethyl, propyl, isopropyl, and butyl groups are examples of methyl, ethyl, propyl, isopropyl, and butyl groups. Examples include the isobutyl group, tert-butyl group, and n-hexyl group. Specifically, as cycloalkyl groups having 3 to 6 carbon atoms, the cyclopropyl group is Examples include cyclobutyl groups, cyclopentyl groups, and cyclohexyl groups. Examples of aryl groups having 6 to 12 carbon atoms include phenyl, naphthyl, and biphenyl groups. Examples such as the basics can be given as concrete examples.

[0191] Also, Ar 2 The arylene group represented by the above structural formula (Ar-1) to (Ar The group represented by -18) can be applied. Note that Ar 2 Can be used as The basis is not limited to these.

[0192] Also, R 21 and R 22 These are, independently, hydrogen and an alkyl group having 1 to 6 carbon atoms. A group, a cycloalkyl group having 3 to 6 carbon atoms, or a substituted or unsubstituted cycloalkyl group having 6 carbon atoms. Represents any aryl group up to 13 carbon atoms. Represents alkyl groups with 1 to 6 carbon atoms. Specifically, these include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group. Examples include the 3-C1 group, tert-butyl group, and n-hexyl group. Specifically, examples of cycloalkyl groups having 6 or more carbon atoms include cyclopropyl groups and cyclobutyl groups. Examples include the cyclopentyl group, cyclohexyl group, etc. Also, a group with 6 carbon atoms. Examples of aryl groups having 13 carbon atoms include phenyl, naphthyl, biphenyl, and fluorine groups. Renyl groups can be given as specific examples. Furthermore, the aryl groups and phenyl groups mentioned above can also be cited. The group may have substituents, and these substituents may be bonded to each other to form a ring. Substituents include alkyl groups having 1 to 6 carbon atoms, and cycloalkyl groups having 3 to 6 carbon atoms. A aryl group or an aryl group having 6 to 12 carbon atoms can also be selected as a substituent. It is possible. Specifically, alkyl groups having 1 to 6 carbon atoms include methyl groups, ethyl groups, and propyl groups. Ropyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, n-hexyl Examples include C3 to C6 cycloalkyl groups. Specifically, these are cyclopropyl group, cyclobutyl group, cyclopentyl group, and cyclohexyl Examples include groups such as carbon atoms. In addition, as aryl groups having 6 to 12 carbon atoms, f Specific examples include phenyl groups, naphthyl groups, and biphenyl groups.

[0193] Also, R 21 and R 22 The alkyl or aryl group represented by the above structure is, for example, Groups represented by formulas (R-1) to (R-29) can be applied. The groups that can be used as aryl groups are not limited to these.

[0194] Also, general formulas (401) to (417), general formulas (201) to (218), general formula ( 301) to (315), and Ar 2 , R 21 and R 22 The substituents that can be present are For example, alkyl groups or aryl groups represented by the above structural formulas (R-1) to (R-24). The group can be applied. It can be used as an alkyl group or an aryl group. The basis is not limited to these.

[0195] The specific structures of the compounds listed above include, for example, the following structural formulas (500) to (50 Examples of compounds represented by 3) are shown.

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[0197] Furthermore, the emission peak exhibited by the host material 132 is triple that of the guest material 131 (phosphorescent material). Term MLCT (Metal to Ligand Charge Transfer) transition The absorption band, more specifically, the absorption band on the longest wavelength side, is overlapped with the host material 132. It is preferable to select guest material 131 (phosphorescent material). This improves the luminescence efficiency. This can result in a dramatically improved light-emitting element. However, instead of phosphorescent material, a thermal activation delay can be used. When using fluorescent materials, the absorption band on the longest wavelength side is the singlet absorption band. preferable.

[0198] ≪Guest Material 131≫ Guest material 131 (phosphorescent material) can be iridium, rhodium, or platinum-based organic Examples include metal complexes, or metal complexes in particular, organoiridium complexes, such as iridium Orthometallic complexes are preferred. 4H-triazole is a suitable ligand for orthometallation. Ligands, 1H-triazole ligands, imidazole ligands, pyridine ligands, pyrimidines Examples include ligands, pyrazine ligands, or isoquinoline ligands. Examples include platinum complexes having porphyrin ligands.

[0199] Furthermore, as guest material 131 (phosphorescent material), the LUMO level of host material 132 is It has a low LUMO level, and the LUMO and HOMO levels of the host material 132 are The host material 132 has an energy difference higher than the LUMO level and the HOMO level. And it is preferable to select guest material 131 (phosphorescent material). This improves the luminous efficiency This allows for a light-emitting element that is high in voltage and driven at a low voltage.

[0200] Examples of substances that have a blue or green emission peak include tris{2-[5-(2 -methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazo [Ir-3-yl-κN2]phenyl-κC}iridium(III) (abbreviation: Ir(mpp) tz-dmp)3), Tris(5-methyl-3,4-diphenyl-4H-1,2,4-) Ryasolato) Iridium(III) (abbreviation: Ir(Mptz)3), Tris[4-(3- [Biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazolato] Lydium(III) (abbreviation: Ir(iPrptz-3b)3), Tris[3-(5-Bif [Phenyl)-5-isopropyl-4-phenyl-4H-1,2,4-triazolato]iridi Um(III) (abbreviation: Ir(iPr5btz)3), a 4H-triazole skeleton organometallic iridium complexes having (OC-6-22)-tris{5-cyano-2-[ 4-(2,6-diisopropylphenyl)-5-(2-methylphenyl)-4H-1,2 ,4-triazole-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-triazole-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-triazole-3-yl-κN 2 ]phenyl-κC}iridium(II 4H with an electron-withdrawing group such as I) (abbreviation: Ir(mpptz-diBuCNp)3) -Organometallic iridium complexes having a triazole skeleton, or 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-Triazolat) Iridium(III) (Abbreviation: Ir(P) Organometallic iridium complexes with a 1H-triazole skeleton, such as rptz1-Me)3) The body, or 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]phenantridina It's like Iridium(III) (abbreviation: Ir(dmpimpt-Me)3) iridium organometallic complexes having a tetrahedron skeleton, and bis[2-(4',6'-difluorophenyl] Nyl)pyridinate-N,C 2’ Iridium(III) tetrakis(1-pyrazolyl) RATH (abbreviation: FIr6), bis[2-(4',6'-difluorophenyl)pyridinate -N,C 2’ Iridium(III) picolinate (abbreviation: Firpic), bis{2- [3',5'-Bis(trifluoromethyl)phenyl]pyridinato-N,C 2’ Iridi Um(III) picolinate (abbreviation: Ir(CF3ppy)2(pic)), bis[2- (4',6'-difluorophenyl)pyridinate-N,C 2’ Iridium (III) Phenyl acetone (abbreviated as Fir(acac)) with electron-withdrawing groups Examples include organometallic iridium complexes with pyridine derivatives as ligands. Among those mentioned above, Nitrogen-containing skeletons such as 4H-triazole skeleton, 1H-triazole skeleton, and imidazole skeleton. Organometallic iridium complexes with a five-membered heterocyclic skeleton have high triplet excitation energies. Furthermore, it is particularly preferable because it offers excellent reliability and luminous efficiency.

[0201] Furthermore, examples of substances that have a green or yellow emission peak include tris(4-methyl Iridium(III) (abbreviation: Ir(mppm)3), 6-phenylpyrimidinato Tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: I r(tBuppm)3), (acetylacetonate)bis(6-methyl-4-phenylpyryl) Iridium(III) (abbreviation: Ir(mppm)2(acac)), (acetyl Luacetonato)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-dimethicone} Lu-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)( Abbreviation: Organometallic irritants with a pyrimidine skeleton, such as Ir(dppm)2(acac) Dium complexes, and (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazine Iridium(III) (abbreviation: Ir(mppr-Me)2(acac)), (acetyl Luacetonato)bis(5-isopropyl-3-methyl-2-phenylpyradinato)iridi Pyrazine bones like Um(III) (abbreviation: Ir(mppr-iPr)2(acac)) iridium organometallic complexes with a specific classification, and tris(2-phenylpyridinato-N,C) 2’ ) Iridium(III) (abbreviation: Ir(ppy)3), bis(2-phenylpyridinate-N) ,C 2’ Iridium(III) acetylacetonate (abbreviation: Ir(ppy)2(ac) ac)), bis(benzo[h]quinolinate)iridium(III)acetylacetonate (Abbreviation: Ir(bzq)2(acac)), Tris(benzo[h]quinolinato)iridiu Mu(III) (abbreviation: Ir(bzq)3), Tris(2-phenylquinolinato-N,C) 2 ’ ) Iridium(III) (abbreviation: Ir(pq)3), bis(2-phenylquinolinazole- N,C 2’ Iridium(III) acetylacetonate (abbreviation: Ir(pq)2(ac) Organometallic iridium complexes having a pyridine skeleton, such as ac)), and bis(2,4-diph Enyl-1,3-oxazolato-N,C 2’ Iridium(III) Acetylaceton (abbreviation: Ir(dpo)2(acac)), bis{2-[4'-(perfluorophenicol) [Phenyl]pyridinate-N,C 2’ Iridium(III) acetylacetonate ( Abbreviation: Ir(p-PF-ph)2(acac)), bis(2-phenylbenzothiazolat -N,C 2’Iridium(III) acetylacetonate (abbreviation: Ir(bt)2(a) In addition to organometallic iridium complexes such as CAC, there are also tris(acetylacetonate)(monophenate). Nanthroline terbium(III) (abbreviation: Tb(acac)3(Phen)) Examples include rare earth metal complexes. Among those mentioned above, organometallic ylids having a pyrimidine skeleton are particularly noteworthy. Dium complexes are particularly preferred because they offer outstanding reliability and luminous efficiency.

[0202] Furthermore, examples of substances that have 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 (5 mdppm)2(dpm)), bis[4,6-di(naphthalene-1-yl)pyrimid Nat] (dipivaloylmethanato) Iridium(III) (Abbreviation: Ir(d1npm)2) Organometallic iridium complexes having a pyrimidine skeleton such as dpm, and (acetylacet Tonato)bis(2,3,5-triphenylpyradinato)iridium(III) (abbreviation: I r(tppr)2(acac)), bis(2,3,5-triphenylpyrazinate)(dipy Valoylmethanato) Iridium(III) (abbreviation: Ir(tppr)2(dpm)), ( Acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato] A pyrazine skeleton like lysium(III) (abbreviation: Ir(Fdpq)2(acac)) The organometallic iridium complexes and tris(1-phenylisoquinolinato-N,C) 2’ ) Iridium(III) (abbreviation: Ir(piq)3), bis(1-phenylisoquinolinate) -N,C 2’ ) Iridium(III) acetylacetonate (abbreviation: Ir(piq)2( In addition to organometallic iridium complexes with a pyridine skeleton such as acac), 2, 3, 7, 8,12,13,17,18-Octaethyl-21H,23H-Porphyrin Platinum(II) Platinum complexes such as (abbreviation: PtOEP) and tris(1,3-diphenyl-1,3-p Europium(III) (Abbreviation: Eu(DB) M)3(Phen)), Tris[1-(2-tenoyl)-3,3,3-trifluoroacetate Tonato (monophenanthroline) europium(III) (abbreviation: Eu(TTA)3) Examples include rare earth metal complexes such as Phen). Among those mentioned above, the pyrimidine skeleton The organometallic iridium complex possesses outstanding reliability and luminescence efficiency, and is therefore particularly preferred. Furthermore, organometallic iridium complexes having a pyrazine skeleton can produce a red emission with good chromaticity. It is possible.

[0203] Furthermore, among the iridium complexes mentioned above, organogold complexes having pyrimidine or pyrazine skeletons are also available. Iridium complexes have high electron-accepting ligands, which tends to result in lower LUMO levels. This is suitable for one aspect of the present invention. Also suitable for halogen groups such as fluoro groups, or cyano groups. Compounds with electron-withdrawing substituents (e.g., iridium complexes) also have LUMO levels. It is suitable because the value tends to be low.

[0204] Furthermore, the light-emitting material contained in the light-emitting layer 130 and the light-emitting layer 135 is a triplet excitation energy Any material that can convert energy into light emission is acceptable. In addition to phosphorescent materials, thermally activated delayed fluorescence materials can also be used as materials. Where it says "optical material," you may substitute it with "thermally activated delayed fluorescence material."

[0205] ≪Host Material 133≫ As for the host material 133, a HOMO level lower than the HOMO level of the host material 132 is selected. The host material has a LUMO level higher than the LUMO level of the guest material 131. It is preferable to select 133, host material 132, and guest material 131. Therefore, it is possible to create a light-emitting element that has high luminous efficiency and can be driven at a low voltage. For material 133, the materials exemplified as host material 132 may be used.

[0206] Furthermore, as the host material 133, a material with higher electron transport capabilities than hole transport can be used. Yes, 1 x 10 -6 cm 2 It is preferable that the material has an electron mobility of / Vs or higher. Examples of materials that readily accept electrons (materials with electron transport properties) include nitrogen-containing heteroaromatic compounds. Compounds having a π-electron-deficient heteroaromatic ring skeleton, such as those found in materials, and zinc and aluminum-based metals. Complexes can be used. Specifically, quinoline ligands, benzoquinoline ligands, Metal complexes having an oxazole ligand or a thiazole ligand, or oxadiazole Derivatives, triazole derivatives, benzimidazole derivatives, quinoxaline derivatives, diben Zoquinoxaline derivatives, phenanthroline derivatives, pyridine derivatives, bipyridine derivatives, Examples include compounds such as 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-quinolinolate)(4-phenylphenolate) Luminium(III) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation) Examples include metal complexes having a quinoline skeleton or a benzoquinoline skeleton, such as Znq. In addition, bis[2-(2-benzoxazolyl)phenolate]zinc(II) Abbreviation: ZnPBO), bis[2-(2-benzothiazolyl)phenolate]zinc(II) Metal complexes having oxazole or thiazole ligands (abbreviated as ZnBTZ) Others can also be used. Furthermore, in addition to metal complexes, 2-(4-biphenylyl)-5 -(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD) or, 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazo [Il-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1,3, 4-Oxadiazole-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-Triazole-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), vasophenanthroline (abbreviation: BPhen), vasocuproin (abbreviation: B Heterocyclic compounds such as CP, and 2-[3-(dibenzothiophen-4-yl)phenyl] Dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-( [Dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxali (Abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazole-9-I [biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDB) q) 2-[4-(3,6-diphenyl-9H-carbazole-9-yl)phenyl]di Benzo[f,h]quinoxaline (abbreviation: 2CzPDBq-III), 7-[3-(dibenz[f,h]quinoxaline) Zothiophene-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 7mDB) TPDBq-II), and 6-[3-(dibenzothiophen-4-yl)phenyl]di Benzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II), 2-[3-(3, 9'-bi-9H-carbazole-9-yl)phenyl]dibenzo[f,h]quinoxaline (Abbreviation: 2mCzCzPDBq), 4,6-bis[3-(phenanthrene-9-yl)f [enyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(4-diben Zothienyl phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6- Bis[3-(9H-carbazole-9-yl)phenyl]pyrimidine (abbreviation: 4,6mC) Heterocyclic compounds having a diazine skeleton such as zP2Pm, and 2-{4-[3-(N-Fe)}. Nyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}- Triazines such as 4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn) Heterocyclic compounds having a din skeleton, or 3,5-bis[3-(9H-carbazole-9-yl] )phenyl]pyridine (abbreviation: 35DCzPPy), 1,3,5-tri[3-(3-pyridine) Heterocyclization of pyridine skeletons such as [zyl]phenyl]benzene (abbreviation: TmPyPB) Compound, 4,4'-bis(5-methylbenzoxazole-2-yl)stilbene (abbreviation: Heteroaromatic compounds such as BzOs can also be used. Among the heterocyclic compounds mentioned above, Also, triazine skeleton, diazine (pyrimidine, pyrazine, pyridazine) skeleton, and pyr Heterocyclic compounds having at least one din skeleton are preferred because they are stable, reliable, and have good reliability. Furthermore, heterocyclic compounds having this skeleton exhibit high electron transport properties and contribute to reducing the driving voltage. Also, poly(2,5-pyridinediyl) (abbreviation: PPy), poly[(9,9-dihexyl) (Abbreviation: PF) -Py), poly[(9,9-dioctylfluorene-2,7-diyl)-co-(2,2 High molecular weight compounds such as '-bipyridine-6,6'-diyl' (abbreviation: PF-BPy) It can also be used. The substances described here are mainly 1 × 10 -6 cm 2 Electron transfer of / Vs or greater It is a substance that possesses mobility. Furthermore, any substance with higher electron transport capabilities than holes is also acceptable, except as described above. You may use the following substance.

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

[0209] As a hole-transporting material, a material with higher hole transport capabilities than electron transport can be used, ×10 -6 cm 2 It is preferable that the material has a hole mobility of / Vs or greater. Specifically This uses aromatic amines, carbazole derivatives, aromatic hydrocarbons, stilbene derivatives, etc. This is possible. Furthermore, the hole-transporting material may be a polymer compound.

[0210] These materials with high hole transport capabilities include, specifically, aromatic amine compounds such as N, N'-di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviation: DT) DPPA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenyl Mino]biphenyl (abbreviation: DPAB), N,N'-bis{4-[bis(3-methylphenyl [amino]phenyl]-N,N'-diphenyl-(1,1'-biphenyl)-4,4' -Diamine (abbreviation: DNTPD), 1,3,5-tris[N-(4-diphenylaminophen) Examples include [phenyl]-N-phenylaminobenzene (abbreviation: DPA3B), etc. .

[0211] Furthermore, as a carbazole derivative, specifically, 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 (Aminophenyl)-N-(1-naphthyl)amino]-9-phenylcarbazole (abbreviation) :PCzTPN2), 3-[N-(9-phenylcarbazole-3-yl)-N-phenyl Luamino]-9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis[N- (9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarb Zol (abbreviation: PCzPCA2), 3-[N-(1-naphthyl)-N-(9-phenylcate Luvazole-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1) Examples include:

[0212] In addition, other carbazole derivatives include 4,4'-di(N-carbazolyl)bife Nyl (abbreviated as CBP), 1,3,5-tris[4-(N-carbazolyl)phenyl]bene Zen (abbreviation: TCPB), 9-[4-(10-phenyl-9-antryl)phenyl]- 9H-carbazole (abbreviation: CzPA), 1,4-bis[4-(N-carbazolyl)phen [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 Tracene (abbreviation: DPPA), 2-tert-butyl-9,10-bis(4-phenyl Enyl anthracene (abbreviation: t-BuDBA), 9,10-di(2-naphthyl)ant Helical (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) Chil)anthracene, 9,9'-bianthryl, 10,10'-diphenyl-9,9'- Biantryl, 10,10'-bis(2-phenylphenyl)-9,9'-biantryl ,10,10'-bis[(2,3,4,5,6-pentaphenyl)phenyl]-9,9' -Biantril, Anthracene, Tetracene, Rubren, Perylene, 2, 5, 8, 11- Examples include tetra(tert-butyl)perylene. In addition, pentacene, coro Nen and other similar materials can also be used. In this way, 1 × 10 -6 cm 2 Hole mobility of / Vs or greater It is more preferable to use aromatic hydrocarbons having 14 to 42 carbon atoms.

[0214] Furthermore, aromatic hydrocarbons may have a vinyl skeleton. Examples of group hydrocarbons include 4,4'-bis(2,2-diphenylvinyl)biphenyl (Abbreviation: DPVBi), 9,10-bis[4-(2,2-diphenylvinyl)phenyl] Examples include anthracene (abbreviated as DPVPA).

[0215] Also, poly(N-vinylcarbazole) (abbreviation: PVK) and poly(4-vinyltriphen 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 High molecular weight compounds such as (phenyl)benzidine (abbreviated as Poly-TPD) can also be used. can.

[0216] Furthermore, as a material with high hole transport properties, for example, 4,4'-bis[N-(1-naphthium [N-phenylamino]biphenyl (abbreviated as NPB or α-NPD) or N,N'- Bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4, 4'-Diamine (abbreviation: TPD), 4,4',4''-Tris(carbazole-9-yl) ) Triphenylamine (abbreviation: TCTA), 4,4',4''-tris[N-(1-naphtholamine) [1'-TNATA]-N-phenylaminotriphenylamine (abbreviation: 1'-TNATA), 4,4 ',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)trife 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}phenylamine N (abbreviation: DFLADFL), N-(9,9-dimethyl-2-diphenylamino-9H- Fluoren-7-yl)diphenylamine (abbreviation: DPNF), 2-[N-(4-diphenyl [Nylaminophenyl)-N-phenylamino]spiro-9,9'-bifluorene (abbreviation: DPASF), 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl) Triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9- Phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBBi1B) P), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazole-3-yl) Triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''- (9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBN) BB), 4-phenyldiphenyl-(9-phenyl-9H-carbazole-3-yl) Min (abbreviation: PCA1BP), N,N'-bis(9-phenylcarbazole-3-yl) -N,N'-diphenylbenzene-1,3-diamine (abbreviation: PCA2B), N,N', N''-triphenyl-N,N',N''-tris(9-phenylcarbazole-3-I) (L)Benzene-1,3,5-triamine (abbreviation: PCA3B), N-(4-biphenyl) -N-(9,9-dimethyl-9H-fluoren-2-yl)-9-phenyl-9H-cal Bazole-3-amine (abbreviation: PCBiF), N-(1,1'-biphenyl-4-yl) -N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9-di Methyl-9H-fluoren-2-amine (abbreviation: PCBBiF), 9,9-dimethyl-N -phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl] Luolen-2-amine (abbreviation: PCBAF), N-phenyl-N-[4-(9-phenyl -9H-carbazole-3-yl)phenyl]spiro-9,9'-bifluoren-2-a Min (abbreviation: PCBASF), 2-[N-(9-phenylcarbazole-3-yl)-N -phenylamino]spiro-9,9'-bifluorene (abbreviation: PCASF), 2,7-bi S[N-(4-diphenylaminophenyl)-N-phenylamino]spiro-9,9'- Bifluoren (abbreviation: DPA2SF), N-[4-(9H-carbazole-9-yl) [phenyl]-N-(4-phenyl)phenylaniline (abbreviation: YGA1BP), N,N'- Bis[4-(carbazole-9-yl)phenyl]-N,N'-diphenyl-9,9-di Aromatic amine compounds such as methylfluorene-2,7-diamine (abbreviation: YGA2F), etc. It can also be used. Furthermore, 3-[4-(1-naphthyl)-phenyl]-9-phenyl -9H-carbazole (abbreviation: PCPN), 3-[4-(9-phenanthril)-pheni [Lu]-9-phenyl-9H-carbazole (abbreviation: PCPPn), 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 Nilcarbazole (abbreviation: CzTP), 3,6-di(9H-carbazole-9-yl)- 9-phenyl-9H-carbazole (abbreviation: PhCzGI), 2,8-di(9H-carbazole) Zole-9-yl)-dibenzothiophene (abbreviation: Cz2DBT), 4-{3-[3-( 9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviated) Name: mmDBFFLBi-II), 4,4',4''-(benzene-1,3,5-torii 1,3,5-tri(dibenzofuran) (abbreviation: DBF3P-II), 1,3,5-tri(dibenzofuran) 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- [Iyl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV), 4 -[3-(triphenylene-2-yl)phenyl]dibenzothiophene (abbreviation: mDBT) Amine compounds such as PTp-II, carbazole compounds, thiophene compounds, and furan compounds The following can be used: substances, fluorene compounds, triphenylene compounds, phenanthrene compounds, etc. Yes, it is possible. Among the compounds mentioned above, the pyrrole skeleton, furan skeleton, thiophene skeleton, and Compounds having at least one aromatic amine skeleton are stable, reliable, and preferred. Furthermore, compounds having this skeleton exhibit high hole transport properties, contributing to a reduction in driving voltage.

[0217] Furthermore, the light-emitting layer 130 and the light-emitting layer 135 can also be composed of two or more layers. For example, the first light-emitting layer and the second light-emitting layer are stacked in order from the hole transport layer side to form a light-emitting layer 13 When 0 or the light-emitting layer 135 is used, the host material of the first light-emitting layer has hole transport properties. This configuration uses materials and employs an electron-transporting material as the host material for the second light-emitting layer. Furthermore, even if the light-emitting material of the first light-emitting layer and the second light-emitting layer is the same material, Even if they are different materials, even if they are materials that have the function of emitting light of the same color, The material may also have the function of emitting light of a color. Two light-emitting layers of different colors By using different light-emitting materials that have the function of emitting light, multiple light sources can be obtained simultaneously. This is possible. In particular, the light emitted by the two light-emitting layers is used in each light-emitting layer so that it becomes white. It is preferable to select a light-emitting material.

[0218] Furthermore, in the light-emitting layer 130, materials other than the host material 132 and the guest material 131 are used. It may also be present. In addition, in the light-emitting layer 135, host material 133, host material 132 It may also have materials other than guest material 131.

[0219] Furthermore, the light-emitting layer 130 and the light-emitting layer 135 are produced by vapor deposition (including vacuum deposition) and inkjet. It can be formed by methods such as the printing method, coating method, and gravure printing. In addition to the materials mentioned above... , inorganic compounds or polymer compounds such as quantum dots (oligomers, dendrimers, polymers) It may have (etc.).

[0220] Quantum dots Quantum dots are semiconductor nanocrystals ranging in size from a few nanometers to tens of nanometers, with a size of 1 × 10⁻¹⁶. 3 From 1 x 10 6 It is composed of about 100 atoms. The energy of a quantum dot depends on its size. Because of this shift, even quantum dots composed of the same material will emit different light waves depending on their size. The lengths are different. Therefore, by changing the size of the quantum dots used, light emission can be easily achieved. The wavelength can be changed.

[0221] Furthermore, quantum dots have a narrow peak width in their emission spectrum, resulting in emission with good color purity. It is possible. Furthermore, the theoretical internal quantum efficiency of quantum dots is said to be 100%. Furthermore, the proportion of organic compounds exhibiting phosphorescence far exceeds 25%, which is significantly higher than the 25% of organic compounds exhibiting fluorescence. It is equivalent to a physical object. Therefore, by using quantum dots as a light-emitting material... It is possible to obtain light-emitting elements with high luminescence efficiency. Moreover, quantum dots, which are inorganic materials, Because it also has excellent intrinsic stability, it is possible to obtain a desirable light-emitting element from the standpoint of lifespan. can.

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

[0223] Specifically, cadmium selenide, cadmium sulfide, cadmium telluride, and selenium sulfide. Lead, zinc oxide, zinc sulfide, zinc telluride, mercury sulfide, mercury selenide, mercury telluride, arsenic 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, sele Arsenic arsenide, arsenic telluride, antimony sulfide, antimony selenide, antimony telluride, Bismuth sulfide, bismuth selenide, bismuth telluride, silicon, silicon carbide, germanium M, tin, selenium, tellurium, boron, carbon, phosphorus, boron nitride, boron phosphide, boron arsenide Aluminum nitride, aluminum sulfide, barium sulfide, barium selenide, barium telluride Beryllium, 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, molybdenum sulfide Density, vanadium oxide, tungsten oxide, tantalum oxide, titanium oxide, zirconium oxide Aluminum oxide, silicon nitride, germanium nitride, barium titanate, selenium and ammonium compounds. Compounds of lead and cadmium, compounds of indium, arsenic and phosphorus, 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; copper and Examples include compounds of ion and sulfur, and combinations thereof, but these include It is not limited. Furthermore, using so-called alloy-type quantum dots whose composition is expressed in any ratio. This is also good. For example, a quantum dot of cadmium, selenium, and sulfur alloy can be used by changing the elemental content ratio. By changing the emission wavelength, it is possible to alter the emission wavelength, making it one of the effective methods for obtaining blue light emission. There are two.

[0224] Quantum dot structures include core type, core-shell type, and core-multishell type. Either of these can be used, but another inorganic ion with a wider band gap can be used to cover the core. By forming a shell with the material, defects and dangling bones present on the nanocrystalline surface can be eliminated. The effects of the luminescence can be reduced. This greatly improves the quantum efficiency of the luminescence. It is preferable to use A-shell type or core-multi-shell type quantum dots. Examples of materials include zinc sulfide and zinc oxide.

[0225] Furthermore, because quantum dots have a high proportion of surface atoms, they are highly reactive and prone to aggregation. Therefore, a protective agent is attached to the surface of the quantum dot or a protective group is provided. It is preferable that the protective agent is attached or a protective group is provided. This prevents aggregation and increases solubility in the solvent. Furthermore, it reduces reactivity and electrical... It is also possible to improve stability. Examples of protective agents (or protective groups) include polio Polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene Polyoxyethylene alkyl ethers such as ethylene oleyl ether, tripropyl phosphate Fins, tributylphosphine, trihexylphosphine, trioctylphosphine, etc. Trialkylphosphines, polyoxyethylene n-octylphenyl ether, polio Polyoxyethylene alkylphenyl ethers such as xyethylene n-nonylphenyl ether Tel compounds, tri(n-hexyl)amines, tri(n-octyl)amines, tri(n-decyl) ) Tertiary amines such as amines, tripropylphosphine oxide, tributylphosphine Oxide, trihexylphosphine oxide, trioctylphosphine oxide, tridec Organophosphorus compounds such as sylphosphine oxide, polyethylene glycol dilaurate, Polyethylene glycol diesters such as polyethylene glycol distearate, and Organic nitrogen compounds such as nitrogen-containing aromatic compounds like pyridine, lutidine, colidine, and quinolines. , hexylamine, octylamine, decylamine, dodecylamine, tetradecylamine aminoalkanes such as hexadecylamine and octadecylamine, and dibutyl sulfide Dialkyl sulfides such as dipropyl sulfate, dipropyl sulfate such as dimethyl sulfoxide and dibutyl sulfoxide Organic sulfur compounds such as sulfur-containing aromatic compounds including sulfur sulfoxides and thiophenes, palmite Higher fatty acids such as tinic acid, stearic acid, and oleic acid, alcohols, and sorbitan fatty acid Polyesters, fatty acid-modified polyesters, tertiary amine-modified polyurethanes, polyethylene Examples include mines, etc.

[0226] Quantum dots have a larger band gap as their size decreases, so they can produce the desired wave. The size is adjusted appropriately to obtain sufficient light. Therefore, the emission of quantum dots shifts towards the blue side, that is, towards the higher energy side. By changing the size of the swatch, the wavelengths of the ultraviolet, visible, and infrared spectra can be adjusted. The emission wavelength can be adjusted across the region. The size (diameter) of the quantum dot is A range of 0.5 nm to 20 nm, preferably 1 nm to 10 nm, is commonly used. Furthermore, the narrower the size distribution of quantum dots, the narrower the emission spectrum becomes. This allows for emission with good color purity. Furthermore, the shape of the quantum dots is not particularly limited. It may be spherical, rod-shaped, disc-shaped, or in any other shape. Note that a rod-shaped quantum dot is a quantum Since the rod has the function of exhibiting directional light, quantum rods are used as light-emitting materials. By doing so, it is possible to obtain a light-emitting element with better external quantum efficiency.

[0227] By the way, in organic EL elements, the light-emitting material is often dispersed in the host material, and the light-emitting material By suppressing density quenching, the luminescence efficiency is increased. The host material is superior to the luminescent material. The material must have a doublet or triplet excitation energy level. In particular, when using blue phosphorescent materials as light-emitting materials, further triplet excitations occur. A host material is needed that has energy levels and is also excellent in terms of lifespan, and its development is It is extremely difficult. Here, the quantum dot emits light using only the quantum dot itself, without using a host material. Because it can maintain luminescence efficiency even when layers are formed, this is also preferable from the standpoint of lifespan. A light-emitting element can be obtained. When the light-emitting layer is formed using only quantum dots, the quantum dots The structure is preferably a core-shell structure (including a core-multi-shell structure).

[0228] When quantum dots are used as the light-emitting material for the light-emitting layer, the film thickness of the light-emitting layer is 3 nm to 100 nm. The n-thickness is preferably 10 nm to 100 nm, and the quantum dot content in the light-emitting layer is 1 to 1 The volume percentage is set to 00%. However, it is preferable to form the light-emitting layer using only quantum dots. When forming a light-emitting layer by dispersing the quantum dots as a light-emitting material in a host, the host material Disperse quantum dots in a suitable liquid medium, or dissolve the host material and quantum dots in a suitable liquid medium. Dispersed wet processes (spin coating, casting, die coating, blade coating) Coating method, roll coating method, inkjet method, printing method, spray coating method, curtain coating It can be formed by methods such as the blotting method or the Langmuir-Bludget method. Phosphorescent luminescent material For the light-emitting layer using the above wet process, vacuum deposition is also suitably used. It is possible.

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

[0230] ≪Hole Injection Layer≫ The hole injection layer 111 is a hole injection layer that receives 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, for example, transition metal oxides, f It is formed by tarocyanine derivatives or aromatic amines, etc. Transition metal oxides and For example, molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide Examples include manganese oxides. Phthalocyanine derivatives include phthalocyanine and Examples include metal phthalocyanines. Aromatic amines include benzidine derivatives and phenyl Examples include lendiamine derivatives. Polymer compounds such as polythiophene and polyaniline. It is also possible to use substances, for example, self-doped polythiophenes such as poly(ethylenedi(ethylenedi) Typical examples include oxythiophene / poly(styrene sulfonic acid).

[0231] As the hole injection layer 111, a hole transport material and a material that exhibits electron-accepting properties in relation to it are combined. A layer containing composite material can also be used. Alternatively, a layer containing an electron-accepting material and a positive A lamination of layers containing pore-transporting material may also be used. Between these materials, a steady state or electrical current may be maintained. Charge transfer is possible in the presence of an electron barrier. Examples of materials exhibiting electron-accepting properties include Kinojimeta. Organic acceptors such as chloranil derivatives and hexaazatriphenylene derivatives We can list the following: 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-Hexazatriphenylene (abbreviated) These are compounds that have electron-withdrawing groups (halogen groups or cyano groups), such as HAT-CN. Furthermore, transition metal oxides, such as oxides of Group 4 to Group 8 metals, can be used. Specifically, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, acid These include tungsten oxide, manganese oxide, and rhenium oxide. Among them, molybdenum oxide is airborne. Among them, it is preferable because it is stable, has low hygroscopicity, and is easy to handle.

[0232] As a hole-transporting material, a material with higher hole transport capabilities than electron transport can be used, ×10 -6 cm 2 It is preferable that the material has a hole mobility of / Vs or greater. Specifically Aromatic amines and carbazoles were listed as hole transport materials that can be used in the light-emitting layer. A nitrite derivative, aromatic hydrocarbon, stilbene derivative, etc., can be used. The transportable material may be a polymer compound.

[0233] ≪Hole transport layer≫ The hole transport layer 112 is a layer containing a hole transportable material, and is an example of the material used for the hole injection layer 111. The hole transport material shown can be used. The hole transport layer 112 is in the hole injection layer 111. Because it has the function of transporting the injected holes to the light-emitting layer, the hole injection layer 111 has the highest occupied orbital. (Highest Occupied Molecular Orbital, HOMO It is preferable to have the same or close HOMO level as the level (also known as the HOMO level).

[0234] Also, 1 x 10 -6 cm 2 It is preferable that the substance has a hole mobility of / Vs or higher. However, other materials may be used if they have higher hole transport capabilities than electron transport. Furthermore, the layer containing the material with high hole transport properties may be a single layer, or a double layer consisting of the aforementioned material. You may stack more than this amount.

[0235] ≪Electron transport layer≫ The electron transport layer 118 passes through the electron injection layer 119 to the other of the pair of electrodes (electrode 101 or electron It has the function of transporting electrons injected from pole 102) to the light-emitting layer. This allows the use of materials with higher electron transport capabilities than holes, resulting in 1 × 10⁻⁶ -6 cm 2 / Vs It is preferable that the material has the above electron mobility. Compounds that readily accept electrons (electron Examples of materials with electron transport properties include π-electron-deficient heteroaromatic compounds such as nitrogen-containing heteroaromatic compounds. Fragrance compounds and metal complexes can be used. Specifically, they can be used in the light-emitting layer. The electron transport materials listed are quinoline ligands, benzoquinoline ligands, and oxazoles. Ligands, or metal complexes having thiazole ligands, oxadiazole derivatives, tria Zole derivatives, benzimidazole derivatives, quinoxaline derivatives, dibenzoquinoxaline Derivatives, phenanthroline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives Examples include the body and triazine derivatives. Also, 1 × 10 -6 cm 2 Electron transfer of / Vs or greater It is preferable that the material has mobility. Furthermore, it is preferable that the material has higher electron transport capabilities than holes. If so, materials other than those mentioned above may be used as the electron transport layer. Also, the electron transport layer 118 is In addition to a single layer, two or more layers made of the above-mentioned material may be stacked.

[0236] Furthermore, even if a layer for controlling the movement of electron carriers is provided between the electron transport layer 118 and the light-emitting layer, Good. This involves adding a small amount of a substance with high electron-trapping properties to a material with high electron-transporting properties, as described above. The added layer suppresses the movement of electron carriers, thereby balancing the carriers. This makes it possible to adjust the settings. This configuration prevents electrons from penetrating the light-emitting layer. This is highly effective in suppressing problems that may arise (for example, reduced device lifespan).

[0237] Furthermore, n-type compound semiconductors may also be used, such as titanium dioxide, zinc oxide, and silicon dioxide. Element, tin oxide, tungsten oxide, tantalum oxide, barium titanate, barium zirconate Zirconium oxide, hafnium oxide, aluminum oxide, yttrium oxide, di silicate Oxides such as ruconium, nitrides such as silicon nitride, cadmium sulfide, zinc selenide Zinc sulfide and the like 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. It has the function of being, for example, Group 1 metals, Group 2 metals, or their oxides and halides. Carbonates and the like can be used. In addition, the electron transport material shown above and the electron transport material therefor Composite materials exhibiting electron-donating properties can also be used. Examples of electron-donating materials include: Examples include Group 1 metals, Group 2 metals, or oxides thereof. Specifically These include lithium fluoride, sodium fluoride, cesium fluoride, calcium fluoride, and lithium. Use alkali metals, alkaline earth metals, or compounds thereof, such as oxides. This can be done. Furthermore, rare earth metal compounds such as erbium fluoride can be used. Alternatively, an electride may be used in the electron injection layer 119. Examples of such electride include: Examples include substances obtained by adding a high concentration of electrons to a mixed oxide of calcium and aluminum. Furthermore, even if the electron injection layer 119 is made of a material that can be used in the electron transport layer 118, good.

[0239] Furthermore, the electron injection layer 119 is a composite made by mixing an organic compound and an electron donor. Materials may be used. Such composite materials are created when electrons are released from the organic compound by an electron donor. Therefore, it exhibits excellent electron injection and electron transport properties. In this case, as an organic compound... Preferably, the material is one that is excellent at transporting the generated electrons, specifically, for example, the material described above. The electron transport layer 118 can be composed of materials (such as metal complexes or heteroaromatic compounds). The electron donor can be any substance that exhibits electron-donating properties towards organic compounds. Alkali metals, alkaline earth metals, and rare earth metals are preferred, as are lithium and sodium. Examples include cesium, magnesium, calcium, erbium, and ytterbium. Furthermore, alkali metal oxides and alkaline earth metal oxides are preferred, as are lithium oxides and calcium oxides. Examples include sium oxide and barium oxide. Also, Lewis plates such as magnesium oxide. Bases can also be used. Additionally, organic compounds such as tetrathiafulvalene (abbreviated as TTF) can be used. Objects can also be used.

[0240] Furthermore, 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. It can be formed by the above-mentioned method. In addition, the light-emitting layer, hole injection layer, hole transport layer, electron In addition to the materials mentioned above, the transport layer and electron injection layer also contain inorganic compounds such as quantum dots and high-molecular-weight materials. Sub-compounds (oligomers, dendrimers, polymers, etc.) may also be used.

[0241] ≪A pair of electrodes≫ Electrodes 101 and 102 function as the anode or cathode of the light-emitting element. 101 and electrode 102 are made of metals, alloys, conductive compounds, and mixtures or laminates thereof. It can be formed using [a specific method / tool].

[0242] Either electrode 101 or electrode 102 is formed by a conductive material having the function of reflecting light. Preferably, this is done. The conductive material is aluminum (Al) or an Al-containing alloy. Examples include gold. Alloys containing Al include Al and L (where L is titanium (Ti) and neodymium). Includes (one or more of Nd, Ni, and La) Examples include alloys containing Al and Ti, or Al, Ni, and La. Aluminum has low resistance and high light reflectivity. Also, aluminum is found in the Earth's crust. Because it is abundant and inexpensive, using aluminum reduces the cost of manufacturing light-emitting devices. It can reduce the amount of silver (Ag), or Ag and N (N is yttrium). Y), Nd, Magnesium (Mg), Ytterbium (Yb), Al, Ti, Gallium ( Ga), zinc (Zn), indium (In), tungsten (W), manganese (Mn), Tin (Sn), iron (Fe), nickel, copper (Cu), palladium (Pd), iridium (Ir ), or alloys containing one or more gold (Au) may be used. Examples of alloys 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, and alloys containing silver and ytterbium Examples include alloys containing tungsten, chromium (Cr), and molybdenum (Mo). ), transition metals such as copper and titanium can be used.

[0243] Furthermore, the light emitted from the light-emitting layer passes through one or both of electrodes 101 and 102. And it is removed. Therefore, at least one of electrode 101 and electrode 102 transmits light. Preferably, it is formed from a conductive material having the function of being visible. The light transmittance is 40% or more and 100% or less, preferably 60% or more and 100% or less, and That resistivity is 1 × 10⁻⁶ -2 Examples include conductive materials with a conductivity of Ω·cm or less.

[0244] Furthermore, electrodes 101 and 102 have the function of transmitting light and the function of reflecting light. It may be formed from a conductive material having a visible light reflectance of 20. The resistivity is between % and 80%, preferably between 40% and 70%, and its resistivity is 1 × 10⁻⁶. -2 Examples of conductive materials include those with a conductivity of Ω·cm or less. For example, conductive metals, alloys, and conductive materials. It can be formed using one or more types of chemical compounds. Specifically, for example, Indium tin oxide (ITO), silicon, or silicon oxide Indium tin oxide (abbreviated as ITSO), indium oxide-zinc oxide (Indi Indium-tin oxide containing titanium (indium zinc oxide), indium Metals such as indium oxide containing titanium oxide, tungsten oxide, and zinc oxide. Oxides can be used. Also, the degree to which light is transmitted (preferably 1 nm to 30 nm) A thin metal film with a thickness of m or less can be used. Examples of metals include Ag, or Alloys such as Ag and Al, Ag and Mg, Ag and Au, and Ag and Yb can be used.

[0245] In this specification, etc., a material having the function of transmitting light is defined as a material having the function of transmitting visible light. Any material that has and is conductive is acceptable, for example, ITO as described above. In addition to oxide conductors, the collection includes oxide semiconductors or organic conductors containing organic materials. Examples of organic conductors include those obtained by mixing an organic compound with an electron donor. Examples include composite materials, such as composite materials formed by mixing organic compounds with electron acceptors. It is possible to use inorganic carbon-based materials such as graphene. Preferably, the ratio is 1 × 10⁻⁶. 5 Ω·cm or less, more preferably 1 × 10⁻⁶ 4 Ω·cm The following applies:

[0246] Furthermore, by stacking multiple of the above materials, one of the electrodes 101 and 102 can be made They may form both.

[0247] Furthermore, in order to improve the light extraction efficiency, the electrode having a light-transmitting function is brought into contact with the A material with a refractive index higher than that of the electrode may be formed. Such a material may transmit visible light. Any material that has the function of being conductive is acceptable, and even if it is a conductive material, it does not have that function. Other options include oxide conductors, oxide semiconductors, and organic materials. Examples of organic materials include the light-emitting layer, hole injection layer, hole transport layer, electron transport layer, or electric Examples of materials used in the sub-injection layer include those shown in the example. Also, inorganic carbon-based materials and thin films that allow light to pass through are also examples. These metals can also be used. Using these materials with high refractive indices, several nanometers to tens of nanometers Multiple layers may be stacked.

[0248] When electrode 101 or electrode 102 functions as a cathode, the work function is small. It is preferable that the material has a (3.8 eV or less) energy. For example, it is preferable that it has elements from Group 1 or Group 2 of the periodic table. Elements belonging to the group (alkali metals such as lithium, sodium, and cesium, calcium, stoichiometric compounds) Alkaline earth metals such as rontium, magnesium, etc., and alloys containing these elements (for example, Rare earth metals such as Ag and Mg, Al and Li, europium (Eu), Yb, and these rare earths Metal alloys, aluminum alloys, silver alloys, etc., can be used.

[0249] Furthermore, when electrode 101 or electrode 102 is used as the anode, the work function is large (4. It is preferable to use a material with a voltage of 0 eV or higher.

[0250] Furthermore, electrodes 101 and 102 are made of a conductive material that has the function of reflecting light and a material that transmits light. It may also be laminated with a conductive material having a function of passing through. In that case, electrode 101 and electrode 1 02 can resonate the light of a desired wavelength from each light-emitting layer, thereby intensifying the light of the desired wavelength. It is preferable because it can have a function to adjust the optical distance.

[0251] The methods for forming the film of electrodes 101 and 102 include sputtering, vapor deposition, printing, and coating. MBE (Molecular Beam Epitaxy), CVD, Pulse Ray The deposition method, ALD (Atomic Layer Deposition), etc., are used as appropriate. It is possible.

[0252] Circuit board Furthermore, a light-emitting element according to one aspect of the present invention is placed on a substrate made of glass, plastic, or the like. It is fine to manufacture it. In terms of the order in which it is manufactured on the substrate, it is fine to stack them in order from the electrode 101 side. You may also stack them sequentially starting from pole 102.

[0253] Examples of substrates on which a light-emitting element according to one aspect of the present invention can be formed include glass and quartz. , or plastic can be used. A flexible substrate may also be used. A substrate is a flexible substrate that can be bent, for example, polycarbonate Examples include plastic substrates made of nate, polyarylate, etc. Also, films, Inorganic vapor-deposited films can also be used. Note: The manufacturing process for light-emitting elements and optical elements. Anything other than these that functions as a support in the context is acceptable. Alternatively, Any device that has the function of protecting optical elements and other optical components is acceptable.

[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. One example of such a substrate is a semiconductor substrate. Plates (e.g., single crystal substrates or silicon substrates), SOI substrates, glass substrates, quartz substrates, plus Includes tic substrates, metal substrates, stainless steel substrates, and stainless steel foil. Substrate, tungsten substrate, substrate with tungsten foil, flexible substrate, bonding Examples include films, paper containing fibrous materials, or substrate films. A glass substrate is one example. For example, barium borosilicate glass, aluminoborosilicate glass, or soda-lime glass. These include the following. Examples of flexible substrates, laminated films, and base films are as follows: Examples include polyethylene terephthalate (PET) and polyethylene. Phthalates (PEN), polyethersulfones (PES), polytetrafluoroethylene There are plastics such as PTFE. Alternatively, as an example, there are resins such as acrylic. It contains oil, etc. Or, as an example, polypropylene, polyester, polyvinyl fluoride Examples include polyvinyl chloride, or polyamide, polyimide, Examples include aramid, epoxy, inorganic vapor-deposited films, or 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. The release layer is provided on top of the light-emitting element. After partially or completely completing the child component, it is separated from the circuit board and used for transferring it to another circuit board. This allows for the transfer of light-emitting elements to substrates with poor heat resistance or flexible substrates. Oh, the aforementioned delamination layer has, for example, a laminated inorganic film structure of a tungsten film and a silicon oxide film. Configurations such as the one shown, or a configuration in which a resin film such as polyimide is formed on the substrate, can be used.

[0256] In other words, a light-emitting element is formed using one substrate, and then the light-emitting element is transferred to another substrate. The light-emitting element may be placed on a different substrate. An example of a substrate on which the light-emitting element is placed is the above In addition to the substrates mentioned above, there are also cellophane substrates, stone substrates, wood substrates, and cloth substrates (natural fibers (silk, cotton, Hemp), synthetic fibers (nylon, polyurethane, polyester) or regenerated fibers (acetate) (including t, cupro, rayon, recycled polyester, etc.), leather substrate, or rubber substrate. These substrates can be used to create light-emitting elements that are less prone to breakage and have high heat resistance. This can be a child, a lightweight light-emitting element, or a thinned light-emitting element.

[0257] Furthermore, a field-effect transistor (FET), for example, is formed on the aforementioned substrate, and the FET and The light-emitting element 150 may be fabricated on electrically connected electrodes. This allows the FET to This allows us to create an active-matrix type display device that controls the driving of the light-emitting element 150.

[0258] In this embodiment, one aspect of the present invention has been described. Or, other embodiments may be described. In this context, one aspect of the present invention will be described. However, this aspect of the present invention is not limited to these. Not done. In other words, various aspects of the invention are described in this embodiment and other embodiments. Therefore, one aspect of the present invention is not limited to a specific aspect. For example, one aspect of the present invention While an example of its application to a light-emitting element has been shown, one aspect of the present invention is not limited thereto. For example, depending on the circumstances, one aspect of the present invention may be suitable for a light-emitting element. It is not necessary to use it. Alternatively, for example, in one aspect of the present invention, the triplet excitation energy is used to emit light. A guest material having the ability to be converted to a host material, and at least one host material. Furthermore, 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 of the host material is the energy difference between the LUMO level and the HOMO level While an example has been shown where the energy difference is greater than that of the position, one aspect of the present invention is not limited thereto. No. In some cases, or depending on the circumstances, in one aspect of the present invention, for example, guest material The material does not need to have the function of converting triplet excitation energy into light emission. Alternatively, The LUMO level of the host material does not necessarily have to be lower than that of the host material. Alternatively, The energy difference between the LUMO level and the HOMO level of the guest material is equal to the energy difference between the LUMO level and the HOMO level of the host material. It does not need to be greater than the energy difference between the position and the HOMO level. Or, for example, the present invention In one embodiment, the host material has a singlet excitation energy level and a triplet excitation energy level. An example was given where the difference is greater than 0 eV and less than or equal to 0.2 eV, but one aspect of the present invention is this This is not limited to the above. Depending on the circumstances, in one aspect of the present invention, for example, The host material has a difference of 0 between its singlet excitation energy level and its triplet excitation energy level. It can be greater than 2eV.

[0259] The configuration shown in this embodiment can be used in appropriate combination with other embodiments. Cut.

[0260] (Embodiment 2) In this embodiment, the light-emitting element has a configuration different from that shown in Embodiment 1. The light-emitting mechanism of the said light-emitting element will be explained below with reference to Figures 5 and 6. In Figures 5(A) and 6(A), the parts have the same function as those indicated by the symbols in Figure 1(A). In some cases, a similar hatch pattern is used, and the code is omitted. Also, if it has a similar function... Sections that are similar to those mentioned are marked with the same symbol, and detailed explanations may be omitted.

[0261] <Example of light-emitting element configuration 1> Figure 5(A) is a schematic cross-sectional view of the light-emitting element 250.

[0262] The light-emitting element 250 shown in Figure 5(A) has a pair of electrodes (electrode 101 and electrode 102) between them. , multiple light-emitting units (in Figure 5(A), light-emitting unit 106 and light-emitting unit 1 08) has. One of the multiple light-emitting units is an EL layer 10 It is preferable to have a configuration similar to that of 0. That is, the light-emitting element 150 shown in Figure 1 and shown in Figure 3 The light-emitting element 152 has one light-emitting unit, and the light-emitting element 250 has multiple light-emitting units It is preferable to have a net. In addition, in the light-emitting element 250, the electrode 101 functions as an anode. Assuming that electrode 102 functions as a cathode, the following explanation will be given, but the configuration of the light-emitting element 250 and The opposite is also acceptable.

[0263] Furthermore, in the light-emitting element 250 shown in Figure 5(A), the light-emitting unit 106 and the light-emitting unit 108 is stacked, and between the light-emitting unit 106 and the light-emitting unit 108 there is an electric current A bio-layer 115 is provided. Note that the light-emitting unit 106 and the light-emitting unit 108 have the same configuration. However, different configurations are also acceptable. For example, it is preferable to use an EL layer 100 in the light-emitting unit 106. It's nice.

[0264] Furthermore, 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, knit 106 also includes a hole injection layer 111, a hole transport layer 112, and an electron transport layer. It has a layer 113 and an electron injection layer 114. The light-emitting unit 108 also has a light-emitting layer 120 In addition, there is 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 a hole transport material to which an acceptor substance, which is an electron acceptor, is added. Even with such a configuration, the electron transport material is combined with a donor substance that acts as an electron donor. This is also acceptable. Furthermore, both of these configurations may be stacked.

[0266] If the charge generation layer 115 contains a composite material of an organic compound and an acceptor substance, The composite material used is a composite material that can be used in the hole injection layer 111 shown in Embodiment 1. That's all. As for organic compounds, aromatic amine compounds, carbazole compounds, aromatic carbon compounds Various compounds are used, such as hydrogen and polymer compounds (oligomers, dendrimers, polymers, etc.). It can exist. Furthermore, as an organic compound, its hole mobility is 1 × 10⁻⁶. -6 cm 2 / Vs It is preferable to apply materials that meet the above criteria. However, materials that have higher hole transport capabilities than electron transport capabilities. If so, other materials may be used. Composite materials of organic compounds and acceptor substances. Because the material has excellent carrier injection and carrier transport properties, it enables low-voltage and low-current operation. This can be achieved. Furthermore, the anode side of the light-emitting unit is in contact with the charge generation layer 115. In this case, the charge generation layer 115 also plays the role of a hole injection layer or hole transport layer of the light-emitting unit. Therefore, the light-emitting unit is configured without a hole injection layer or a hole transport layer. That is also acceptable. Alternatively, if the cathode side of the light-emitting unit is in contact with the charge generation layer 115. This means that the charge generation layer 115 also plays the role of an electron injection layer or electron transport layer of the light-emitting unit. Therefore, the light-emitting unit is configured without an electron injection layer or an electron transport layer. That's good too.

[0267] Furthermore, the charge generation layer 115 is a layer containing a composite material of an organic compound and an acceptor substance, and other It may be formed as a laminated structure by combining layers made of the following materials. For example, organic A layer containing a composite material of a compound and an acceptor substance, and one selected from among electron-donating substances. A layer containing the compound and a compound with high electron transport properties may be formed by combining them. A layer containing a composite material of an organic compound and an acceptor substance is combined with a layer containing a transparent conductive film. They may be formed together.

[0268] Furthermore, the charge generation layer 115 sandwiched between the light-emitting unit 106 and the light-emitting unit 108 is electric When a voltage is applied to electrode 101 and electrode 102, electrons are injected into one of the light-emitting units. Any method that injects holes into the other light-emitting unit is acceptable. For example, in Figure 5(A), When a voltage is applied such that the potential of electrode 101 is higher than the potential of electrode 102, The charge generation layer 115 injects electrons into the light-emitting unit 106 and holes into the light-emitting unit 108. Enter.

[0269] Furthermore, the charge generation layer 115 has light transmission to visible light (specifically) from the viewpoint of light extraction efficiency. It is preferable that the charge generation layer 115 has a visible light transmittance of 40% or more. Furthermore, the charge generation layer 115 has lower conductivity than the pair of electrodes (electrode 101 and electrode 102). It still works.

[0270] By forming the charge generation layer 115 using the materials described above, the light-emitting layer is stacked in the field This can suppress the rise in drive voltage during operation.

[0271] Furthermore, Figure 5(A) illustrates a light-emitting element having two light-emitting units. However, the same principle can also be applied to light-emitting elements that have three or more light-emitting units stacked on top of each other. As shown in the light-emitting element 250, multiple light-emitting units are placed between a pair of electrodes in a charge generation layer. By partitioning and arranging the elements, high-brightness light emission is possible while maintaining a low current density, and further This enables the creation of light-emitting elements with a long lifespan. Furthermore, it enables the creation of light-emitting elements with low power consumption. .

[0272] Furthermore, of the multiple units, at least one unit has the configuration shown in Embodiment 1. By applying this technology, it is possible to provide a light-emitting element with high luminescence efficiency.

[0273] Furthermore, the light-emitting layer 170 of the light-emitting unit 106 is the same as the light-emitting layer 13 shown in Embodiment 1. It is preferable to have a configuration of 0 or an emissive layer 135. In this way, the light-emitting element 250 is This is suitable as a light-emitting element with high luminescence efficiency.

[0274] Furthermore, the light-emitting layer 120 of the light-emitting unit 108 is as shown in Figure 5(B), guest The device comprises material 121 and host material 122. The guest material 121 is a fluorescent material. The following explains this.

[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 (electrode 101 and electrode 102) or a charge generation layer Excitons are generated when holes recombine in the light-emitting layer 120. Guest material 1 Compared to 21, there is a large amount of host material 122, so by generating excitons, the host material An excited state of material 122 is formed.

[0277] An exciton is a carrier (electron and hole) pair. An exciton has energy. Therefore, the material from which excitons are generated enters an excited state.

[0278] If the excited state of the formed host material 122 is a singlet excited state, then the host material 12 Singlet excitation energy is transferred from the S1 level of material 2 to the S1 level of guest material 121. Then, a singlet excited state is formed in guest material 121.

[0279] Since guest material 121 is a fluorescent material, the singlet excited state in guest material 121 Once formed, the guest material 121 rapidly emits light. At this time, to obtain high luminescence efficiency... Therefore, it is preferable that the fluorescence quantum yield of guest material 121 is high. The same applies in case 1, when carriers recombine and the resulting excited state is a singlet excited state. That is the case.

[0280] Next, when a triplet excited state of the host material 122 is formed by carrier recombination... This will be explained. The energy levels of the host material 122 and guest material 121 in this case. The correlation of the ranks is shown in Figure 5(C). The notation and symbols in Figure 5(C) are as follows: Furthermore, the T1 level of the host material 122 is lower than the T1 level of the guest material 121. Since this is preferable, Figure 5(C) illustrates this case, but the T1 level of the host material 122 This may be higher than the T1 level of 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 host material 122 ·T FH :T1 level of host material 122

[0282] As shown in Figure 5(C), triplet-triplet annihilation (TTA: Triplet-Tripl Triplets generated by carrier recombination (et Annihilation) Excitons interact with each other, exchanging excitation energy and spin angular momentum. By doing so, the S1 level of the host material 122 (S FH ) has the energy A reaction occurs that converts to a singlet exciton (see Figure 5(C) TTA). Host material 122 The singlet excitation energy of is S FH Therefore, guest material 121 has lower energy. S1 level (S FG Energy transfer occurs to (see Figure 5(C) Route E5), and the guest A singlet excited state is formed in material 121, and the guest material 121 emits light.

[0283] Furthermore, if the density of triplet excitons in the light-emitting layer 120 is sufficiently high (for example, 1 × 10⁻¹⁰ -12 cm -3 (The above) ignores the deactivation of a single triplet exciton and considers two closely spaced triplet excitons. We can consider only the reaction caused by the initiator.

[0284] Furthermore, when carriers recombine in guest material 121 and a triplet excited state is formed... The triplet excited state of guest material 121 is thermally deactivated, making it difficult to utilize for luminescence. However, the T1 level (T) of the host material 122 FH ) is a T1 standard of guest material 121 Place(T FG If it is lower than ), the triplet excitation energy of guest material 121 is, 21 T1 levels (T FG ) from the T1 level of host material 122 (T FH Energy transfer to ) It is possible to do this (see Figure 5(C) Route E6), and it is then used for TTA.

[0285] In other words, the host material 122 has a triplet excitation energy, and a singlet excitation energy is obtained by TTA. It is preferable that it has the function of converting into energy. By doing so, the light generated in the light-emitting layer 120 A portion of the triplet excitation energy is obtained by singlet excitation energy by TTA in the host material 122. By converting it into energy and transferring the singlet excitation energy to the guest material 121, fluorescence It becomes possible to extract it as luminescence. To do this, the S1 level (S) of the host material 122 is needed. FH ) is the S1 level (S FG It is preferable that it is higher than ) Also, phos T1 level of material 122 (T FH ) is the T1 level (T FG ) lower It is preferable.

[0286] In particular, the T1 level of guest material 121 (T FG ) is the T1 level of the host material 122 ( T FH If it is lower than ), the weight ratio of host material 122 to guest material 121 is It is preferable that the weight ratio of the guest material 121 is low. Specifically, the host material 122 is 1 and The weight ratio of guest material 121 in that case is preferably greater than 0 and 0.05 or less. This reduces the probability of carrier recombination in guest material 121. Furthermore, the T1 level of host material 122 (T FH ) from guest material 121 T1 level (T FG ) This can reduce the probability of energy transfer occurring.

[0287] The host material 122 may be composed of a single compound, or it may be composed of multiple compounds. It's fine if it's done.

[0288] Furthermore, the light-emitting unit 106 and the light-emitting unit 108 have guest materials with different light-emitting colors. In this case, the emission from the light-emitting layer 120 is on the shorter wavelength side than the emission from the light-emitting layer 170. It is preferable to have a configuration that has a -. A material having a high triplet excitation energy level The light-emitting element used tends to degrade in brightness quickly. Therefore, a light-emitting layer that exhibits short wavelength emission is used. By using TA, it is possible to provide light-emitting elements with minimal brightness degradation.

[0289] <Example of light-emitting element configuration 2> Figure 6(A) is a schematic cross-sectional view of the light-emitting element 252.

[0290] The light-emitting element 252 shown in Figure 6(A) is similar to the light-emitting element 250 shown earlier, and consists of a pair of electrodes. Between electrodes 101 and 102, there are multiple light-emitting units (in Figure 6(A), It has a light unit 106 and a light-emitting unit 110). At least one light-emitting unit is , it has a similar configuration to the EL layer 100. Furthermore, the light-emitting unit 106 and light-emitting unit 110 The configuration can be the same or different.

[0291] Furthermore, in the light-emitting element 252 shown in Figure 6(A), the light-emitting unit 106 and the light-emitting unit 110 and are stacked, and between the light-emitting unit 106 and the light-emitting unit 110 there is an electric current A raw layer 115 is provided. For example, it is preferable to use an EL layer 100 in the light-emitting unit 106. It's nice.

[0292] Furthermore, the light-emitting element 252 has a light-emitting layer 140 and a light-emitting layer 170. In addition to the light-emitting layer 170, knit 106 also includes a hole injection layer 111, a hole transport layer 112, and an electron transport layer. It has a layer 113 and an electron injection layer 114. The light-emitting unit 110 also has a light-emitting layer 140 In addition, there is 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] Furthermore, of the multiple units, at least one unit has the configuration shown in Embodiment 1. By applying this technology, it is possible to provide a light-emitting element with high luminescence efficiency.

[0294] Furthermore, it is preferable that the light-emitting layer of the light-emitting unit 110 has a phosphorescent material. The light-emitting layer 140 of unit 110 has a phosphorescent material, and the light-emitting unit 106 has The light-emitting layer 170 has the same configuration as the light-emitting layer 130 or light-emitting layer 135 shown in Embodiment 1. This is preferable. 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 made of guest material 1, as shown in Figure 6(B). It comprises 41 and a host material 142. Furthermore, the host material 142 is an organic compound 142_ It comprises 1 and organic compound 142_2. Note that the guest material 14 of the light-emitting layer 140 1 is a phosphorescent material, which will be explained below.

[0296] ≪Light-emitting mechanism of light-emitting layer 140≫ Next, the light-emitting mechanism of the light-emitting layer 140 will be explained below.

[0297] The organic compound 142_1 and organic compound 142_2 present in the light-emitting layer 140 form an excited complex. It forms.

[0298] The combination of organic compound 142_1 and organic compound 142_2 forms excited complexes with each other. Any combination that is possible is acceptable, but one of the compounds must be a hole-transporting compound. It is more preferable that the other compound is an electron-transporting compound.

[0299] Organic compound 142_1, organic compound 142_2, and guest material in the light-emitting layer 140 The correlation of energy levels with 141 is shown in Figure 6(C). Note that the notation in Figure 6(C) and The 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 excited complex ·T PE : T1 level of the excited complex

[0300] Organic compound 142_1 and organic compound 142_2 form an excited complex, and the S of the excited complex Level 1 (S PE ) and T1 level (T PE ) are adjacent energy levels (Figure 6( C) See Route E7.

[0301] Organic compound 142_1 and organic compound 142_2 receive holes and electrons, one receives a hole and the other receives an electron. By removing it, an excited complex is quickly formed. Alternatively, once one of them enters an excited state, It forms an excited complex by interacting with the other. Therefore, the excited complex in the luminescent layer 140 Most of the risers exist as excited complexes. The excitation energy levels of the excited complexes (S PE Also is T PE ) is a host material (organic compound 142_1 and organic compound 1) that forms an excited complex. 42_2) S1 level (S PH1 and S PH2 ) is lower, therefore lower excitation energy Ghee makes it possible to form an excited state of the host material 142. This makes it possible to emit light. The drive voltage of the child can be reduced.

[0302] And the excited complex (S PE ) and (T PE The energy of both ) is used by guest material 141 Light emission is obtained by shifting to the T1 level of the (phosphorescent material) (see Figure 6(C), routes E8, E9). (see).

[0303] Note that the T1 level of the excited complex (T PE ) is the T1 level (T PG )twist A larger value is preferable. This increases the singlet excitation energy of the generated excited complex. The triplet excitation energy is the S1 level (S) of the excited complex. PE ) and T1 level (T PE )mosquito The T1 level of guest material 141 (T PGEnergy can be transferred to ).

[0304] Furthermore, in order to efficiently transfer excitation energy from the excited complex to the guest material 141, , the T1 level of the excited complex (T PE ) forms an excited complex with each organic compound (organic compound 14 T1 level of 2_1 and organic compound 142_2) (T PH1 and T PH2 ) is equivalent to, Smaller is preferable. This allows each organic compound (organic compound 142_1 and organic Compound 142_2) makes it less likely for the triplet excitation energy of the excited complex to quench. This allows for efficient energy transfer from the excited complex to the guest material 141.

[0305] Furthermore, organic compound 142_1 and organic compound 142_2 efficiently form an excited complex. In order to do so, the HOMO level of one of the organic compounds 142_1 and 142_2 must The fact that one LUMO level is higher than the other HOMO level, and one LUMO level is higher than the other LUMO level. Preferred. For example, if organic compound 142_1 has hole transport properties, and organic compound 142_2 If it has electron transport properties, the HOMO level of organic compound 142_1 is the same as that of organic compound 142_2 It is preferable that the LUMO level is higher than the HOMO level, and the LUMO level of organic compound 142_1 is organically modified. It is preferable that the LUMO level is higher than that of compound 142_2. Alternatively, organic compound 142_ If 2 has hole transport properties and organic compound 142_1 has electron transport properties, then organic compound 1 It is preferable that the HOMO level of 42_2 is higher than that of organic compound 142_1. The LUMO level of organic compound 142_2 is higher than that of organic compound 142_1. This is preferable. Specifically, the HOMO level of organic compound 142_1 and organic compound 142 The energy difference with the HOMO level of _2 is preferably 0.05 eV or more, and more preferably The voltage is 0.1 eV or higher, and more preferably 0.2 eV or higher. The energy difference between the LUMO level of substance 142_1 and the LUMO level of organic compound 142_2 is Preferably 0.05 eV or higher, more preferably 0.1 eV or higher, and even more preferably The voltage is 0.2 eV or higher.

[0306] Furthermore, the combination of organic compound 142_1 and organic compound 142_2 exhibits hole transport properties. In the case of a combination of a compound that possesses electron transport properties and a compound that has electron transport properties, the mixing ratio of the two compounds... This makes it possible to easily control the carrier balance. Specifically, it has hole transport properties. Compounds: Compounds with electron transport properties = preferably in the range of 1:9 to 9:1 (by weight). Furthermore, having this configuration makes it easy to control the career balance. Furthermore, the carrier recombination region can be easily controlled.

[0307] Furthermore, the intermolecular energy transfer between host material 142 (excited complex) and guest material 141 The mechanism of the dynamic process is the same as in Embodiment 1, a Förster mechanism (dipole-dipole interaction). It can be explained by two mechanisms: the (use) mechanism and the Dexter mechanism (electron exchange interaction). The Förster mechanism and the Dexter mechanism can be described in Embodiment 1. .

[0308] Therefore, the triplet excitation of guest material 141 is achieved from the singlet excited state of the host material (excited complex). To facilitate energy transfer to the initial state, the emission spectrum of the excited complex and the gate It is preferable that the absorption band appearing on the longest wavelength side (lowest energy side) of material 141 overlaps with the other band. By doing so, we can increase the efficiency of generating the triplet excited state of guest material 141. ru.

[0309] By configuring the light-emitting layer 140 as described above, the guest material 141 (phosphorescent material) of the light-emitting layer 140 This makes it possible to efficiently obtain light emission from ).

[0310] Furthermore, the processes of routes E7 to E9 shown above are referred to as ExTET(Ex in this specification, etc.). It is sometimes referred to as ciplex-triplet energy transfer. In other words, the light-emitting layer 140 provides the excitation energy from the excited complex to the guest material 141. There is a provision. Note that in this case, it is not necessarily T PE From S PE The reverse interterm crossing efficiency needs to be high. No, S PE Since a high emission quantum yield is not required, a wide range of materials can be selected. It becomes possible.

[0311] Furthermore, the emission from the light-emitting layer 170 has a shorter wavelength peak than the emission from the light-emitting layer 140. It is preferable to have a configuration that has a luminescent element. The child tends to experience rapid brightness degradation. Therefore, by using fluorescence emission for short-wavelength emission, This makes it possible to provide a light-emitting element with minimal brightness degradation.

[0312] In each of the above configurations, the light-emitting unit 106 and the light-emitting unit 108, or the light-emitting unit The luminescence color exhibited by the guest material used in unit 106 and light-emitting unit 110 is as follows: They may be the same or different from each other. (Light-emitting unit 106 and light-emitting unit 108) , or a device in which light-emitting unit 106 and light-emitting unit 110 emit light of the same color from each other. When a guest material with the ability is present, the light-emitting element 250 and light-emitting element 252 have a low current value This is preferable as it results in a light-emitting element that exhibits high luminous brightness. Also, the light-emitting unit 106 and the light-emitting element Knit 108, or light-emitting unit 106 and light-emitting unit 110, are of different colors from each other. If a guest material having the function of emitting light is present, light-emitting element 250 and light-emitting element 252 This is preferable as a light-emitting element that exhibits multicolor light emission. In this case, the light-emitting layer 120 and the light-emitting layer 170 Either one or both of the light-emitting layer 140 and light-emitting layer 170 if By using multiple light-emitting materials with different emission wavelengths in both the light-emitting element 250 and The emission spectrum exhibited by the light-emitting element 252 was a composite of emissions with different emission peaks. Since it becomes light, it will have an emission spectrum with at least two maximum values.

[0313] The above configuration is also suitable for obtaining white light emission. The light-emitting layer 120 and the light-emitting layer 170, Alternatively, by making the light from the light-emitting layer 140 and the light-emitting layer 170 complementary colors to each other, white light is produced. Light emission can be obtained. In particular, white light with high color rendering, or at least red and green light. It is preferable to select guest materials such that the emission has both a blue and a light-colored component.

[0314] Furthermore, at least one of the light-emitting layers 120, 140, and 170 is layered. It may be divided into layers, and each divided layer may contain a different light-emitting material. The light-emitting layer 120, light-emitting layer 140, and light-emitting layer 170 are two or more layers in total. It can also be constructed with layers. For example, the first light-emitting layer and the second light-emitting layer can be placed on the hole transport layer side. When stacking these materials in order to form an emissive layer, the host material for the first emissive layer has hole transport properties. The configuration uses a material that allows electron transport as the host material for the second light-emitting layer. There are cases like this. In this case, the light-emitting material of the first light-emitting layer and the second light-emitting layer is the same material. Even if they are different materials, even if they are materials that have the function of emitting light of the same color, The materials may also have the function of exhibiting light emission of different colors. A configuration having multiple light-emitting materials that have the function of producing three primary colors or four or more light-emitting colors It is also possible to obtain white light emission with high color rendering.

[0315] <Examples of materials that can be used for the light-emitting layer> Next, regarding materials that can be used for the light-emitting layer 120, light-emitting layer 140, and light-emitting layer 170... I will now explain.

[0316] <<Materials that can be used for the light-emitting layer 120>> In the light-emitting layer 120, the host material 122 is the most abundant 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 T1 level of host material 122 is higher than the S1 level of host material 121 (fluorescent material), and the G It is preferable that the level is lower than the T1 level of the fluorescent material 121.

[0317] In the light-emitting layer 120, there are no particular limitations on the guest material 121, but anthracene is also acceptable. Derivatives, tetracene derivatives, chrysene derivatives, phenanthrene derivatives, pyrene derivatives, Lylene 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-antryl)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-fluorine) [Len-9-yl]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-dia Min (abbreviation: 1,6tBu-FLPAPrn), N,N'-diphenyl-N,N'-bis [4-(9-phenyl-9H-fluoren-9-yl)phenyl]-3,8-dicyclophenyl Xylpyrene-1,6-diamine (abbreviation: ch-1,6FLPAPrn), N,N'-bi Su[4-(9H-carbazole-9-yl)phenyl]-N,N'-diphenylstilbe n-4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazole-9-yl) -4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA) , 4-(9H-carbazol-9-yl)-4'-(9,10-diphenyl-2-ant) Lyl)triphenylamine (abbreviation: 2YGAPPA), N,9-diphenyl-N-[4- (10-phenyl-9-anthryl)phenyl]-9H-carbazole-3-amine (abbreviated) Name: PCAPA), Perylene, 2,5,8,11-Tetra(tert-butyl)perylene (Abbreviation: TBP), 4-(10-phenyl-9-antryl)-4'-(9-phenyl- 9H-carbazole-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) [enyl]-9H-carbazole-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-carbazole-3-amine (abbreviation: 2 PCAPA), N-[9,10-bis(1,1'-biphenyl-2-yl)-2-ant [Lyl]-N,9-diphenyl-9H-carbazole-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'-bis( (phenyl-2-yl)-N-[4-(9H-carbazole-9-yl)phenyl]-N-f Phenylanthracene-2-amine (abbreviation: 2YGABPhA), N,N,9-triphenyl Luanthracene-9-amine (abbreviation: DPhAPhA), Coumarin 6, Coumarin 545T N,N'-diphenylquinacridone (abbreviation: DPQd), rubren, 2,8-di-te rt-butyl-5,11-bis(4-tert-butylphenyl)-6,12-diphenyl Lutetracene (abbreviation: TBRb), Nile Red, 5,12-bis(1,1'-biphenyl Lu-4-yl)-6,11-diphenyltetracene (abbreviation: BPT), 2-(2-{2- [4-(dimethylamino)phenyl]ethenyl}-6-methyl-4H-pyran-4-yly Dene)propanedinitrile (abbreviation: DCM1), 2-{2-methyl-6-[2-(2,3 ,6,7-tetrahydro-1H,5H-benzo[ij]quinoridine-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-meth (p) acenaphtho[1,2-a]fluorantene-3,10-diamine (abbreviation: p -mPhAFD), 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethicone)] Ru-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinoridine-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]quinoridine-9-yl)ethenyl -4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTB), 2-(2, 6-Bis{2-[4-(dimethylamino)phenyl]ethenyl}-4H-pyran-4-i (Liden)propanedinitrile (abbreviation: BisDCM), 2-{2,6-bis[2-(8- Methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H -Benzo[ij]quinoridine-9-yl)ethenyl]-4H-pyran-4-ylidene} Ropanedinitrile (abbreviation: BisDCJ™), 5,10,15,20-tetraphenyl Bisbenzo[5,6]indeno[1,2,3-cd:1',2',3'-lm]perylene These are some examples.

[0319] Furthermore, in the light-emitting layer 120, the materials that can be used for the host material 122 are: There are no particular limitations, but 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-quinolinolate)(4-phenylphenolate ) Aluminum(III) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (Abbreviation: Znq), bis[2-(2-benzoxazolyl)phenolate]zinc(II) Abbreviation: ZnPBO), bis[2-(2-benzothiazolyl)phenolate]zinc(II) Metal complexes such as (abbreviated as ZnBTZ), 2-(4-biphenylyl)-5-(4-tert- Butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5 -(p-tert-butylphenyl)-1,3,4-oxadiazole-2-yl]ben Zen (abbreviation: 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-benzoimidazo Vasophenanthroline (abbreviation: TPBI), Vasophenanthroline (abbreviation: BPhen), Vasocuproline (Abbreviation: BCP), 9-[4-(5-phenyl-1,3,4-oxadiazole-2- Heterocyclic compounds such as yl(phenyl)-9H-carbazole (abbreviation: CO11), 4,4 '-Bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB) (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) Examples include aromatic amine compounds such as BSPB. Also, anthracene derivatives, ferrous compounds, etc. Nanthrene derivatives, pyrene derivatives, chrysene derivatives, dibenzo[g,p]chrysene derivatives Examples include condensed polycyclic aromatic compounds such as 9,10-diphenylanthracene (Abbreviation: DPAnth), N,N-diphenyl-9-[4-(10-phenyl-9-Anth) Tolyl)phenyl]-9H-carbazole-3-amine (abbreviation: CzA1PA), 4-( 10-phenyl-9-anthryl)triphenylamine (abbreviation: DPhPA), 4-(9 H-carbazole-9-yl)-4'-(10-phenyl-9-antryl)triphenyl Luamine (abbreviation: YGAPA), N,9-diphenyl-N-[4-(10-phenyl-9 -Anthryl)phenyl]-9H-carbazole-3-amine (abbreviation: PCAPA), N ,9-diphenyl-N-{4-[4-(10-phenyl-9-antryl)phenyl]f phenyl-9H-carbazole-3-amine (abbreviation: PCAPBA), N,9-diphenyl ru-N-(9,10-diphenyl-2-anthryl)-9H-carbazole-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 O-phenyl-9-antryl)phenyl]-9H-carbazole (abbreviation: CzPA), 3,6-diphenyl-9-[4-(10-phenyl-9-antryl)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'-biantril (abbreviation: BANT), 9,9'-(still Ben-3,3'-diphenylenanthren (abbreviation: DPNS), 9,9'-(Stilbe n-4,4'-di-diphenanthrene (abbreviation: DPNS2), 1,3,5-tri(1 Examples include pyrenyl benzene (abbreviated as TPB3). Furthermore, these and From among known materials, an energy greater than the energy gap of the above guest material 121 You can use one or more materials that have gaps.

[0320] The light-emitting layer 120 can also be composed of two or more layers. For example, the first When the first light-emitting layer and the second light-emitting layer are stacked in order from the hole transport layer side to form the light-emitting layer 120, A material having hole transport properties is used as the host material for the first light-emitting layer, and the host material for the second light-emitting layer One such configuration involves using materials that possess electron-transporting properties.

[0321] Furthermore, in the light-emitting layer 120, the host material 122 is composed of a certain compound. It is also fine if it is composed of multiple compounds. Alternatively, in the light-emitting layer 120, It may also contain materials other than stock material 122 and 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 the most abundant by weight, and the guest material 141 The (phosphorescent material) is dispersed in the host material 142. Host material 142 of the light-emitting layer 140 ( The T1 level of organic compound 142_1 and organic compound 142_2 is the same as the T level of guest material 141. It is preferable that the level be higher than level 1.

[0323] Organic compound 142_1 includes zinc and aluminum-based metal complexes, as well as oxadiazo Diazepam derivatives, triazole derivatives, benzimidazole derivatives, quinoxaline derivatives, diazepam Dibenzoquinoxaline derivatives, dibenzothiophene derivatives, dibenzofuran derivatives, pyrimidin phenanthroline derivatives, triazine derivatives, pyridine derivatives, bipyridine derivatives, phenanthroline derivatives Examples include conductors. Other examples include aromatic amines and carbazole derivatives. Specifically, using the electron-transporting material and hole-transporting material shown in Embodiment 1, It is possible.

[0324] Organic compound 142_2 is a combination that can form an excited complex with organic compound 142_1. A combination is preferred. Specifically, the electron transport material and hole transport material shown in Embodiment 1. A material can be used. In this case, organic compound 142_1 and organic compound 142_2 The emission peak of the excited complex formed is the triplet MLCT of guest material 141 (phosphorescent material) The absorption band of the Metal to Light Charge Transfer transition, Specifically, organic compound 142_1 and organic compound 142_1 are positioned so as to overlap with the absorption band on the longest wavelength side. It is preferable to select material 142_2 and guest material 141 (phosphorescent material). This allows for the creation of a light-emitting element with dramatically improved luminescence efficiency. However, if the phosphorescent material is replaced... Furthermore, when using thermally activated delayed fluorescence materials, the absorption band on the longest wavelength side is singlet absorption. It is preferable that it be a cascading area.

[0325] Guest material 141 (phosphorescent material) includes iridium, rhodium, or platinum-based organic materials. Examples include metal complexes, or metal complexes in particular, organoiridium complexes, such as iridium Orthometallic complexes are preferred. 4H-triazole is a suitable ligand for orthometallation. Ligands, 1H-triazole ligands, imidazole ligands, pyridine ligands, pyrimidines Examples include ligands, pyrazine ligands, or isoquinoline ligands. Examples include platinum complexes having porphyrin ligands. Specifically, in the embodiment... The material exemplified as guest material 131 shown in 1 can be used.

[0326] The light-emitting material included in the light-emitting layer 140 is capable of converting triplet excitation energy into light emission. Any material will do. A material that can convert the triplet excitation energy into light emission is a phosphorescent material. In addition, thermally activated delayed fluorescence materials can be mentioned. Therefore, the part that was described as phosphorescent material is relevant. Therefore, it is acceptable to interpret this as a thermally activated delayed fluorescence material.

[0327] Furthermore, materials exhibiting thermally activated delayed fluorescence can be subjected to reverse intersystem crossing from a triplet excited state. It may be a material capable of generating a multiplet excited state, or an excited complex (excyplex, also It may be composed of multiple materials that form an Exciplex (also known as an Exciplex).

[0328] When a thermally activated delayed fluorescence material is composed of one type of material, specifically, in the embodiment The thermally activated delayed fluorescence material shown in 1 can be used.

[0329] Furthermore, when using a thermally activated delayed fluorescence material as a host material, two types of excitation complexes are formed. It is preferable to use a combination of compounds of the same type. In this case, the excitation complex shown above is formed The combinations that make up the combination are compounds that readily accept electrons and compounds that readily accept holes. It is particularly preferable to use [this].

[0330] <<Materials that can be used for the light-emitting layer 170>> Materials that can be used for the light-emitting layer 170 include those used for the light-emitting layer shown in Embodiment 1 above. By using materials that can be used, it is possible to create light-emitting elements with high luminescence efficiency. It can be manufactured.

[0331] Furthermore, the emission color of the light-emitting material contained in the light-emitting layer 120, light-emitting layer 140, and light-emitting layer 170 There are no limitations; they can be the same or different. The light emitted from each is mixed. Since it is extracted outside the element, for example, if the light emitted by both is complementary to each other, the light-emitting element The child can emit white light. Considering the reliability of the light-emitting element, the light-emitting layer 120 is included The emission peak wavelength of the light-emitting material is shorter than that of the light-emitting material contained in the light-emitting layer 170. This is preferable.

[0332] Furthermore, the light-emitting unit 106, light-emitting unit 108, light-emitting unit 110, and charge generation Layer 115 can be produced using methods such as vapor deposition (including vacuum deposition), inkjet printing, coating, and gravure printing. It can be formed by the following method.

[0333] The configuration shown in this embodiment can be used in appropriate combination with the configurations shown in other embodiments. It is possible to be there.

[0334] (Embodiment 3) In this embodiment, the light-emitting element has a configuration different from that shown in Embodiments 1 and 2. An example of this will be explained below using Figures 7 to 10.

[0335] <Example of light-emitting element configuration 1> Figures 7(A) and 7(B) are cross-sectional views showing a light-emitting element according to one embodiment of the present invention. In (B), the same hatching is used in areas that have the same function as the symbols shown in Figure 1(A). In some cases, the code may be omitted as a pattern. Also, similar functions are used in similar places. Symbols may be used, and detailed explanations may be omitted.

[0336] The light-emitting elements 260a and 260b shown in Figures 7(A) and 7(B) are connected to the substrate 200 side. It may also be a bottom-emission type light-emitting element that extracts from the substrate 200 and It may also be a top-emission type light-emitting element that extracts light in the opposite direction. However, one aspect of the present invention is not limited thereto, and the light emitted by the light-emitting element is directed above the substrate 200. It may also be a dual-emission type light-emitting element that emits light from both the upper and lower sides. .

[0337] When the light-emitting element 260a and light-emitting element 260b are of the bottom emission type, electrode 1 Preferably, 01 has the function of transmitting light. Also, electrode 102 reflects light. It is preferable that the light-emitting element 260a and the light-emitting element 260b have a function. In the case of a top-emission type, it is preferable that the electrode 101 has the function of reflecting light. Furthermore, it is preferable that the electrode 102 has the function of transmitting light.

[0338] The light-emitting element 260a and the light-emitting element 260b have an electrode 101 and an electrode 102 on the substrate 200. It has the following: In addition, between electrode 101 and electrode 102, there is a light-emitting layer 123B and a light-emitting layer 123 It has G and a light-emitting layer 123R. It also has a hole injection layer 111 and a hole transport layer 112. It has an electron transport layer 118 and an electron injection layer 119.

[0339] Furthermore, the light-emitting element 260b is part of the configuration of the electrode 101, and the conductive layer 101a and the conductive It has a conductive layer 101b on layer 101a and a conductive layer 101c below the conductive layer 101a. In other words, the light-emitting element 260b has a conductive layer 101a, a conductive layer 101b, and a conductive layer 101c. It has a configuration of clamped electrodes 101.

[0340] In the light-emitting element 260b, the conductive layer 101b and the conductive layer 101c are made of different materials. It may be done in this way, or it may be formed from the same material. The electrode 101 may have the same conductive layer 101a. In the case of a configuration that is sandwiched between electrolytic materials, the etching process in the formation process of the electrode 101 This is preferable because it facilitates pattern formation.

[0341] Furthermore, in the light-emitting element 260b, in the conductive layer 101b or the conductive layer 101c, A configuration having only one of the two offsets is also acceptable.

[0342] Furthermore, the conductive layers 101a, 101b, and 101c of the electrode 101 are each implemented The same configuration and materials as those used for electrode 101 or electrode 102 shown in Form 1 can be used. Cut.

[0343] In Figures 7(A) and 7(B), the region 221B is sandwiched between electrode 101 and electrode 102. A partition wall 145 is located between region 221G and region 221R. The partition wall 145 provides insulation. The partition wall 145 covers the end of the electrode 101 and has an opening that overlaps with the electrode. By providing the wall 145, the electrodes 101 on the substrate 200 in each region are arranged in island-like formations. It becomes possible to separate them.

[0344] Furthermore, in the region where the light-emitting layer 123B and the light-emitting layer 123G overlap with the partition wall 145, They may have overlapping regions. Alternatively, the light-emitting layer 123G and the light-emitting layer 123R may have overlapping regions. In the region where it overlaps with the partition wall 145, it may have overlapping regions. In the region where the light-emitting layer 123R and the light-emitting layer 123B overlap with the partition wall 145, It may have an overlapping region.

[0345] The partition wall 145 only needs to be insulating and is formed using an inorganic or organic material. The inorganic materials include silicon oxide, silicon oxide nitride, silicon nitride oxide, silicon nitride silicon Examples of organic materials include aluminum oxide, aluminum nitride, etc. Examples include photosensitive resin materials such as acrylic resin or polyimide resin.

[0346] Furthermore, a silicon oxidizride 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%. Below, silicon is 25 atomic% to 35 atomic%, and hydrogen is 0.1 atomic% to 10 atomic%. This refers to items included in the following range. A silicon nitride film, in terms of its composition, contains more oxygen than... This refers to a membrane with a high nitrogen content, preferably containing 55 atomic% to 65 atomic% nitrogen and oxygen. 1 atomic% to 20 atomic%, silicon 25 atomic% to 35 atomic%, hydrogen 0.1 This refers to substances that are present in a concentration range of 10% to 10 atomic percent.

[0347] Furthermore, the light-emitting layer 123R, light-emitting layer 123G, and light-emitting layer 123B each exhibit different colors. It is preferable to have a light-emitting material that has the function of emitting red light. For example, the light-emitting layer 123R exhibits red light. By having a light-emitting material that has the function of, region 221R exhibits red light emission, and light-emitting layer 12 Region 221G emits green light because region 3G has a light-emitting material that exhibits a green light. The light-emitting layer 123B has a light-emitting material that exhibits a blue color, thus region 221 B emits blue light. A light-emitting element 260a or light-emitting element 26 has such a configuration. By using 0b as the pixel of the display device, a display device capable of full-color display can be manufactured. This is possible. Also, the film thickness of each light-emitting layer may be the same or different. good.

[0348] Additionally, one or more of the light-emitting layers 123B, 123G, and 123R. The light-emitting layer is at least one of the light-emitting layers 130 and 135 shown in Embodiment 1. It is preferable to have two configurations. By doing so, a light-emitting element with good luminescence efficiency can be fabricated. It is possible.

[0349] Note that one or more of the light-emitting layers 123B, 123G, and 123R may be present. The light-emitting layer may be configured with two or more layers stacked on top of each other.

[0350] As described above, at least one light-emitting layer emits light as shown in Embodiments 1 and 2. Having a layered structure, the light-emitting element 260a or light-emitting element 260b having the light-emitting layer is used as a display device. By using it in the pixels, a display device with high luminous efficiency can be manufactured. That is, A display device having a light-emitting element 260a or a light-emitting element 260b reduces power consumption. It is possible.

[0351] Furthermore, in the direction from which light is extracted from the electrode that extracts light, an optical element (for example, a color filter) is placed. By providing polarizing plates, anti-reflective coatings, etc., the color purity of the light-emitting element 260a and the light-emitting element 260b is improved. The degree can be improved. Therefore, the light-emitting element 260a or light-emitting element 260b The color purity of the display device can be improved. Alternatively, the light-emitting element 260a and the light-emitting element can be improved. External light reflection of 260b can be reduced. Therefore, the light-emitting element 260a or light-emitting element The contrast ratio of a display device having sub-element 260b can be increased.

[0352] Furthermore, other configurations of the light-emitting element 260a and light-emitting element 260b are as follows: The configuration of the light-emitting element in Embodiment 1 and Embodiment 2 should be taken into consideration.

[0353] <Example of light-emitting element configuration 2> Next, Figures 8(A) and 8(B) show examples of configurations different from the light-emitting elements shown in Figures 7(A) and 7(B). We will use this to provide the following explanation.

[0354] Figures 8(A) and 8(B) are cross-sectional views showing a light-emitting element according to one embodiment of the present invention. In (B), the same symbols are used for parts that have the same function as those shown in Figures 7(A) and (B). A hatch pattern may be used, and the symbols may be omitted. Also, in areas with similar functions, Similar symbols may be used, and their detailed explanations may be omitted.

[0355] Figures 8(A) and 8(B) show examples of the configuration of a light-emitting element having a light-emitting layer between a pair of electrodes. The light-emitting element 262a shown in (A) is an upper-surface emitter that extracts light in the direction opposite to the substrate 200. The light-emitting element of the (up-emission) type, the light-emitting element 262b shown in Figure 8(B), is on the substrate 200 side. This is a bottom-emission type light-emitting element that extracts light from the bottom. One embodiment is not limited thereto, and the light emitted by the light-emitting element is on the substrate 200 on which the light-emitting element is formed. It may also be a dual-emission type that extracts material from both the front and the bottom.

[0356] The light-emitting element 262a and the light-emitting element 262b have an electrode 101 and an electrode 102 on the substrate 200. It has electrode 103 and electrode 104. Also, between electrode 101 and electrode 102, At least light is emitted between electrode 102 and electrode 103, and between electrode 102 and electrode 104. It has a layer 170, a light-emitting layer 190, and a charge-generating layer 115. It also has a hole injection layer 111 and , hole transport layer 112, electron transport layer 113, electron injection layer 114, hole injection layer 116 It has a hole transport layer 117, an electron transport layer 118, and an electron injection layer 119.

[0357] Furthermore, the electrode 101 consists of a conductive layer 101a and a conductive layer 101b that is in contact with the conductive layer 101a. , has . Furthermore, electrode 103 has a conductive layer 103a and a conductive layer in contact with the conductive layer 103a 103b and Electrode 104 has a conductive layer 104a and a conductive layer in contact with the conductive layer 104a. It has an electrolytic layer 104b.

[0358] The light-emitting element 262a shown in Figure 8(A) and the light-emitting element 262b shown in Figure 8(B) are electrodes Region 222B sandwiched between electrode 101 and electrode 102, sandwiched between electrode 102 and electrode 103 Between region 222G and region 222R sandwiched between electrode 102 and electrode 104, It has a wall 145. The partition wall 145 is insulating. The partition wall 145 has electrodes 101 and 1 03, and the end of electrode 104 are covered, and the partition wall 145 has an opening that overlaps with the electrode. By doing so, the electrodes on the substrate 200 in each region can be separated into island-like structures. It becomes Noh.

[0359] Furthermore, the charge generation layer 115 is made of a hole transport material to which electron acceptors are attached. By adding materials, or by adding electron donors to electron transport materials, It can be formed if the conductivity of the charge generation layer 115 is as high as that of the pair of electrodes. In addition, the carriers generated by the charge generation layer 115 flow to the adjacent pixels, and then to the adjacent pixels In some cases, the element may emit light unintentionally. Therefore, it is necessary to suppress the unauthorized emission of light from adjacent pixels. In order to achieve this, the charge generation layer 115 is formed of a material with lower conductivity than the pair of electrodes. preferable.

[0360] Furthermore, the light-emitting element 262a and the light-emitting element 262b are located in region 222B, region 222G, and In the direction from which the light emitted from region 222R is extracted, the optical element 224B and the optical element are respectively positioned. The substrate 220 has a sub-element 224G and an optical element 224R. Light emitted from each region It is emitted to the outside of the light-emitting element through each optical element. That is, it is emitted from region 222B. The light is emitted through the optical element 224B, and the light emitted from region 222G is emitted through the optical element The light emitted through 224G and emanating from region 222R is transmitted through optical element 224R. It is launched.

[0361] Furthermore, optical elements 224B, 224G, and 224R receive incident light It has the function of selectively transmitting light exhibiting a specific color. For example, optical element 224B The light emitted from region 222B through the optical element 22 becomes blue light. The light emitted from region 222G via 4G becomes green light, and the optical element The light emitted from region 222R via sub-element 224R is red in color.

[0362] Optical elements 224R, 224G, and 224B include, for example, a colored layer ( Color filters (also called color filters), bandpass filters, and multilayer filters can be applied. Furthermore, a color conversion element can be applied to an optical element. The color conversion element converts the incident light to... This is an optical element that converts light to wavelengths longer than the wavelength of the light in question. It uses quantum dots as color conversion elements. It is preferable to use an element that employs quantum dots. By using quantum dots, the color reproducibility of the display device can be improved. It can improve.

[0363] Furthermore, other optical elements may be placed on optical elements 224R, 224G, and 224B. One or more of these may be arranged in a stack. Other optical elements include, for example, circular polarizers and anti-reflective coatings. A protective film can be provided. The circular polarizing plate is used to extract light emitted from the light-emitting element of the display device. When placed on the receiving side, light incident from outside the display device is reflected inside the display device, and the outside This prevents the phenomenon of ejection from the part. In addition, by providing an anti-reflective coating, the surface of the display device This can reduce the amount of ambient light reflected by the device. This makes the light emitted by the display device clearer. It can be observed.

[0364] In Figures 8(A) and 8(B), the light emitted from each region through each optical element is referred to as blue. Let light exhibiting color (B), light exhibiting green (G), and light exhibiting red (R) be defined as follows: This is schematically illustrated with dashed arrows.

[0365] Furthermore, a light-shielding layer 223 is provided between each optical element. The light-shielding layer 223 is provided in adjacent regions or It has the function of blocking the light emitted from it. Furthermore, a configuration without the light-blocking layer 223 is also acceptable. stomach.

[0366] The light-shielding layer 223 has the function of suppressing the reflection of external light. Alternatively, the light-shielding layer 223 and Therefore, it has the function of preventing the mixing of colors of light emitted from adjacent light-emitting elements. Light-shielding layer 223 and For example, metals, resins containing black pigments, carbon black, metal oxides, and multiple metal oxides. A composite oxide containing a solid solution of a substance can be used.

[0367] Furthermore, optical element 224B and optical element 224G are in the region where they overlap with the light-shielding layer 223. They may have overlapping regions. Alternatively, optical element 224G and optical element 224R refers to the region in which the light-shielding layer 223 overlaps, even if there are overlapping regions between them. Good. Alternatively, optical element 224R and optical element 224B are superimposed on the light-shielding layer 223. Within a given domain, there may be overlapping regions.

[0368] Furthermore, the configuration of the substrate 200 and the substrate 220 having optical elements is as follows: Embodiment 1 You can take it into consideration.

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

[0370] <<Microcavity structure>> Light emitted from the light-emitting layer 170 and the light-emitting layer 190 is directed to a pair of electrodes (for example, electrode 10 Resonance occurs between 1 and electrode 102). Also, the light-emitting layer 170 and light-emitting layer 190 are emitted. It is formed at a position where the light of a desired wavelength is intensified among the incoming light. For example, in the reflection region of electrode 101 The optical distance from the light-emitting region of the light-emitting layer 170 to the optical distance from the reflection region of the electrode 102 to the light-emitting layer 170 By adjusting the optical distance to the light-emitting region, the light emitted from the light-emitting layer 170 can be controlled. This allows for the enhancement of light of a desired wavelength. Also, from the reflection region of electrode 101 to the light-emitting layer 190 The optical distance to the light-emitting region and the distance from the reflection region of electrode 102 to the light-emitting region of light-emitting layer 190. By adjusting the optical distance, the desired wavelength of light emitted from the light-emitting layer 190 can be selected. The light can be intensified. That is, multiple light-emitting layers (here, light-emitting layer 170 and light-emitting layer In the case of a light-emitting element that stacks 190), the optical distance between the light-emitting layer 170 and the light-emitting layer 190 is It is preferable to optimize the separation.

[0371] Furthermore, in the light-emitting element 262a and light-emitting element 262b, a conductive layer (conductive layer 1) is present in each region. By adjusting the thickness of 01b, conductive layer 103b, and conductive layer 104b), the light-emitting layer 170 Furthermore, it is possible to enhance the light of a desired wavelength from 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 electron injection By making the thickness of at least one of the layer 119 and the electron transport layer 118 different, light emission The light emitted from layer 170 and light-emitting layer 190 may be intensified.

[0372] For example, electrodes 101 to 104 are made of a conductive material that has the function of reflecting light. When the refractive index is smaller than the refractive index of the light-emitting layer 170 or the light-emitting layer 190, the electrode The thickness of the conductive layer 101b on 101 is determined by the optical distance between electrode 101 and electrode 102 being m B λ B / 2(m B λ is a natural number, B (These represent the wavelengths of light that are strengthened in region 222B.) Adjust to achieve this. Similarly, the thickness of the conductive layer 103b on electrode 103 is adjusted to match electrode 103 and The optical distance between electrode 102 is m G λ G / 2(m G λ is a natural number, G Stronger in region 222G The wavelengths of light are adjusted to be (represented by). Furthermore, the conductive layer of electrode 104 The film thickness of 104b is such that the optical distance between electrode 104 and electrode 102 is m R λ R / 2(m R is natural number, λ R The wavelengths of light that are strengthened in region 222R are adjusted accordingly.

[0373] Furthermore, if it is difficult to precisely determine the reflection region of electrodes 101 to 104, By assuming that any region of electrode 101 to electrode 104 is a reflective region, the light-emitting layer 170 or The optical distance at which the light emitted from the light layer 190 is intensified may be derived. Also, the light-emitting layer 170 If it is difficult to precisely determine the light-emitting region of the light-emitting layer 190, the light-emitting layer 170 and By assuming that any region of the light layer 190 is an emission region, the emission layer 170 and the emission layer 190 You may also derive the optical distance at which the light emitted from the source is intensified.

[0374] As described above, a microcavity structure is provided, and the optical distance between the pair of electrodes in each region is adjusted. By optimizing the surface, light scattering and absorption near each electrode are suppressed, resulting in a high light extraction efficiency. It is possible to achieve this rate.

[0375] In the above configuration, conductive layer 101b, conductive layer 103b, and conductive layer 104b are light It is preferable that the conductive layer 101b, conductive layer 103b, and conductive The materials constituting layer 104b may be the same or different. When the same material is used for the electrical layer 101b, the conductive layer 103b, and the conductive layer 104b, electrode 10 1. Pattern formation by etching process during the formation of electrodes 103 and 104 is acceptable. This is preferable because it makes things easier. Also, conductive layers 101b, 103b, and 104b are Each layer may have a configuration consisting of two or more layers stacked on top of each other.

[0376] Note that the light-emitting element 262a shown in Figure 8(A) is an upward-emitting type light-emitting element, and therefore is conductive Layer 101a, conductive layer 103a, and conductive layer 104a have the function of reflecting light. Preferably, the electrode 102 has both the function of transmitting light and the function of reflecting light. It is preferable.

[0377] Furthermore, the light-emitting element 262b shown in Figure 8(B) is a bottom-extrusion type light-emitting element, therefore it is conductive Layer 101a, conductive layer 103a, and conductive layer 104a have the function of transmitting light and the function of reflecting light. It is preferable that the electrode 102 has the ability to reflect light. preferable.

[0378] Furthermore, in the light-emitting element 262a and light-emitting element 262b, conductive layer 101a, conductive layer 10 The same material may be used for 3a or the conductive layer 104a, or different materials may be used. When the same material is used for conductive layer 101a, conductive layer 103a, and conductive layer 104a, the light-emitting element The manufacturing costs of the sub-element 262a and the light-emitting element 262b can be reduced. The electrical layer 103a and the conductive layer 104a may each have a configuration in which two or more layers are stacked. stomach.

[0379] Furthermore, the light-emitting layers 170 and 190 in the light-emitting elements 262a and 262b At least one of the configurations shown in Embodiment 1 and Embodiment 2 is included. It is preferable to have this. By doing so, a light-emitting element exhibiting high luminescence efficiency can be fabricated. It is possible.

[0380] Furthermore, the light-emitting layer 170 and the light-emitting layer 190 are, for example, light-emitting layer 190a and light-emitting layer 190b Thus, a configuration in which two layers are stacked on one or both sides may be used. The two light-emitting layers include the first Two types of light-emitting materials, a compound and a second compound, which have the function of exhibiting different colors, are used. By using them, multiple light emission can be obtained simultaneously. In particular, the light emission layer 170 and the light emission layer Select the light-emitting material to be used in each light-emitting layer so that the light emitted by 190 results in a white color. And that is preferable.

[0381] Furthermore, the light-emitting layer 170 or the light-emitting layer 190 has a structure in which three or more layers are stacked, either one or both. It may be a composite material, and may also include a layer that does not contain luminescent material.

[0382] As described above, the configuration of the light-emitting layer shown in Embodiment 1 and Embodiment 2 is at least one By using the light-emitting element 262a or light-emitting element 262b as a pixel of a display device, A display device with high light efficiency can be fabricated. That is, the light-emitting element 262a or the light-emitting element A display device having element 262b can reduce power consumption.

[0383] Regarding the other configurations of the light-emitting element 262a and light-emitting element 262b, 260a or light-emitting element 260b, or the light-emitting elements shown in Embodiment 1 and Embodiment 2 You should consider the configuration of the optical element.

[0384] <Method for fabricating a light-emitting element> Next, a method for manufacturing a light-emitting element according to one aspect of the present invention will be described below using Figures 9 and 10. This section describes the fabrication method for the light-emitting element 262a shown in Figure 8(A). do.

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

[0386] The method for fabricating the light-emitting element 262a described below comprises seven steps, from the first to the seventh. ru.

[0387] ≪Step 1≫ The first step is to create electrodes for the light-emitting element (specifically, conductive layers 101 that constitute the electrodes 101). a) conductive layer 103a constituting electrode 103, and conductive layer 104a constituting electrode 104) This is the process of forming it on the substrate 200 (see Figure 9(A)).

[0388] In this embodiment, a conductive layer having the function of reflecting light is formed on the substrate 200. By processing the conductive layer into a desired shape, conductive layer 101a, conductive layer 103a, and conductive Layer 104a is formed. The conductive layer having the function of reflecting light is made of silver and palladium. A copper alloy film (also called Ag-Pd-Cu film or APC) is used. The process of processing the same conductive layer to form the electrical layer 101a, conductive layer 103a, and conductive layer 104a. This method is preferable because it allows for lower manufacturing costs.

[0389] Note that before the first step, multiple transistors may be formed on the substrate 200. Furthermore, the plurality of transistors, conductive layer 101a, conductive layer 103a, and conductive layer 104a They may be electrically connected to each other.

[0390] ≪Step 2≫ The second step is to have a light-transmitting function on the conductive layer 101a that constitutes the electrode 101. A conductive layer 101b is placed on the conductive layer 103a constituting the electrode 103, and has the function of transmitting light. A conductive layer 103b is placed on the conductive layer 104a constituting the electrode 104, and has the function of transmitting light. This is the step of forming the conductive layer 104b (see Figure 9(B)).

[0391] In this embodiment, conductive layers 101a, 103a, and have the function of reflecting light, On 104a, there are conductive layers 101b, 103b, and respectively, which have the function of transmitting light. By forming 104b, electrodes 101, 103, and 104 are formed. ITSO films are used as the conductive layers 101b, 103b, and 104b.

[0392] Furthermore, the conductive layers 101b, 103b, and 104b, which have the function of transmitting light, can be used multiple times. It may be formed in stages. By forming it in stages, suitable microcaches can be formed in each region. The conductive layers 101b, 103b, and 104b can be formed with a film thickness that creates a vitreous structure. Cut.

[0393] ≪Step 3≫ The third step is to form partition walls 145 that cover the ends of each electrode of the light-emitting element. See Figure 9(C).

[0394] The partition wall 145 has an opening that overlaps with the electrode. The conductive film exposed by the opening. This functions as the anode of the light-emitting element. In this embodiment, the partition wall 145 is made of polyimide resin. Use fat.

[0395] Furthermore, in steps 1 to 3, the EL layer (the layer containing organic compounds) is damaged. Because there is no risk, various film formation methods and microfabrication techniques can be applied. This involves forming a reflective conductive layer using a sputtering method, and then using a lithography method to... A pattern is formed on the electrode layer, and then a dry etching method or a wet etching method is used. Then, by processing the conductive layer into an island shape, the conductive layer 101a and electrode 10 constitute the electrode 101. A conductive layer 103a constituting 3 and a conductive layer 104a constituting electrode 104 are formed. Subsequently, a transparent conductive film is deposited using the sputtering method, and then lithography is used. Then, a pattern is formed on the transparent conductive film, and then a wet etching method is used. Then, the transparent conductive film is processed into an island shape to form electrodes 101, 103, and 104. ru.

[0396] ≪Step 4≫ The fourth step involves a hole injection layer 111, a hole transport layer 112, a light-emitting layer 190, and an electron transport layer. This is a step to form 113, an electron injection layer 114, and a charge generation layer 115 (Figure 10(A)). reference).

[0397] As the hole injection layer 111, a material containing a hole transporting material and an acceptor material is co-evaporated. It can be formed by deposition. Co-deposition is the process of depositing multiple different materials together. This is a vapor deposition method in which evaporation occurs simultaneously from an evaporation source. In addition, the hole transport layer 112 is a hole It can be formed by depositing a transportable material.

[0398] The light-emitting layer 190 can be purple, blue, blue-green, green, yellow-green, yellow, orange, or red. By depositing at least one luminescent guest material selected from among them, the shape is formed. This can be achieved. As guest materials, luminescent organic materials that exhibit fluorescence or phosphorescence can be used. It can be used. Furthermore, the configuration of the light-emitting layer shown in Embodiment 1 and Embodiment 2 can be used. It is preferable to do so. Alternatively, the light-emitting layer 190 may have a two-layer configuration. In that case, 2 Preferably, the light-emitting layers of each layer have light-emitting materials that exhibit different light-emitting colors from one another.

[0399] The electron transport layer 113 can be formed by depositing a material with high electron transport properties. It is possible. Furthermore, the electron injection layer 114 is formed by depositing a material with high electron injection properties. It is possible.

[0400] As the charge generation layer 115, electron acceptors are added to a hole transport material. Deposition of a material, or a material to which an electron donor has been added to an electron transport material. It can be formed with.

[0401] ≪Step 5≫ The fifth step involves a hole injection layer 116, a hole transport layer 117, a light-emitting layer 170, and an electron transport layer. This is a step in which 118, the electron injection layer 119, and the electrode 102 are formed (see Figure 10(B)). .

[0402] The hole injection layer 116 is made of the same material and is made using the same method as the hole injection layer 111 described above. It can be formed more easily. Also, as the hole transport layer 117, the hole transport layer 11 shown above It can be formed using the same materials and methods as in 2.

[0403] The light-emitting layer 170 can be purple, blue, blue-green, green, yellow-green, yellow, orange, or red. By depositing at least one luminescent guest material selected from among them, the shape is formed. This can be achieved. As guest materials, luminescent organic compounds that exhibit fluorescence or phosphorescence can be used. It can be used. Also, the configuration of the light-emitting layer 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 to have the configuration of the light-emitting layer shown in Embodiment 1. Also, light-emitting layer 170 and light-emitting layer 1 It is preferable that 90 has luminescent organic compounds that exhibit different types of luminescence from each other. .

[0404] The electron transport layer 118 is made of the same material and is constructed using the same method as the electron transport layer 113 described above. It can be formed more easily. Also, as the electron injection layer 119, the electron injection layer 11 shown above It can be formed using the same materials and methods as in 4.

[0405] The electrode 102 consists of a reflective conductive film and a translucent conductive film laminated together. It can be formed as follows. Also, the electrode 102 can be a single-layer structure or a multi-layer structure. That's good too.

[0406] After the above process, regions 222 are formed on electrodes 101, 103, and 104, respectively. A light-emitting element having region B, region 222G, and region 222R is formed on the substrate 200.

[0407] Step 6 The sixth step is to place a light-shielding layer 223, optical element 224B, and optical element 224 on the substrate 220. This is the process of forming G and the optical element 224R (see Figure 10(C)).

[0408] As the light-shielding layer 223, a resin film containing black pigment is formed in the desired area. After that, the base On the plate 220 and the light-shielding layer 223, optical element 224B, optical element 224G, and optical element 2 Forming 24R. As the optical element 224B, a resin film containing blue pigment is applied to the desired region. Formed. In addition, as the optical element 224G, a resin film containing green pigment is formed in a desired region. Furthermore, as the optical element 224R, a resin film containing red pigment is formed in the desired region. do.

[0409] ≪Step 7≫ The seventh step is to have a light-emitting element formed on substrate 200 and a light-emitting element formed on substrate 220 The light-shielding layer 223, optical element 224B, optical element 224G, and optical element 224R are attached. This is the process of sealing the parts together using a sealing material (not shown in the diagram).

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

[0411] The configuration shown in this embodiment may be used in appropriate combination with the configurations shown in other embodiments. It is possible to be there.

[0412] (Embodiment 4) In this embodiment, a display device according to one aspect of the present invention will be described using Figures 11 to 19. I will reveal it.

[0413] <Example of display device configuration 1> Figure 11(A) is a top view showing the display device 600, and Figure 11(B) is the same as Figure 11(A) but with a dashed line. This is a cross-sectional view taken along lines AB and the dashed line CD. The display device 600 includes a drive circuit section ( It has a signal line driving circuit section 601, a scan line driving circuit section 603, and a pixel section 602. Furthermore, the signal line drive circuit section 601, the scan line drive circuit section 603, and the pixel section 602 emit light. It has a function to control the light emission of the element.

[0414] Furthermore, the display device 600 includes an element substrate 610, a sealing substrate 604, and a sealing material 605. The area 607 surrounded by the sealing material 605, the routed wiring 608, and the FPC 609 are all included. do.

[0415] Furthermore, the routing wiring 608 is connected to the signal line drive circuit section 601 and the scan line drive circuit section 603. This is wiring for transmitting input signals, and it connects to the FPC609, which is an external input terminal, for video input. It receives signals such as the O signal, clock signal, start signal, and reset signal. Note that here it is FP Only C609 is shown in the diagram, but FPC609 is a printed circuit board (PWB: Pri A wired wiring board may be attached.

[0416] Furthermore, the signal line drive circuit section 601 consists of an N-channel type transistor 623 and a P-channel type A CMOS circuit is formed by combining it with transistor 624. The path section 601 or the scan line drive circuit section 603 includes various CMOS circuits, PMOS circuits, and An NMOS circuit can be used. In addition, in this embodiment, the drive circuit section is mounted on the substrate. The image shows a display device in which the formed driver and pixels are arranged on the same surface, but this is not necessarily required. Alternatively, the drive circuit can be formed externally instead of on the circuit board.

[0417] Furthermore, the pixel section 602 includes a switching transistor 611 and a current control transistor. The lower part electrically connected to the drain of transistor 612 for current control and transistor 612 It has an electrode 613. A partition wall 614 is formed to cover the end of the lower electrode 613. A positive-type photosensitive acrylic resin film can be used as the partition wall 614.

[0418] Furthermore, in order to improve coverage, the upper or lower end of the partition wall 614 has a curved surface with curvature. To ensure that a structure is formed. For example, positive-type photosensitive acrylic is used as the material for the partition wall 614. If so, the upper end of the partition wall 614 will have a curve with a radius of curvature (0.2 μm or more and 3 μm or less). It is preferable to give it a surface. Also, as the partition wall 614, a negative type photosensitive resin or a poly Any type of photosensitive resin can be used.

[0419] Furthermore, the structure of the transistors (transistors 611, 612, 623, 624) is particularly... It is not limited. For example, a staggered transistor may be used. Also, the transistor There are no particular limitations regarding polarity, and it includes N-channel and P-channel transistors. A structure that includes either an N-channel transistor or a P-channel transistor. A structure consisting of only one of the two may also be used. Furthermore, the semiconductor film crystal used in transistors... There are no particular limitations regarding properties. For example, amorphous semiconductor films and crystalline semiconductor films can be used. Yes, it is possible. Also, as semiconductor materials, there are Group 14 (silicon, etc.) semiconductors and compound semiconductors (oxides). Semiconductors (including organic semiconductors), etc., can be used. Examples of transistors include: Energy gap of 2 eV or more, preferably 2.5 eV or more, more preferably 3 eV By using the above oxide semiconductors, the off-current of the transistor can be reduced. Preferably, the oxide semiconductor is 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 ne Examples include odymium (Nd).

[0420] An EL layer 616 and an upper electrode 617 are formed on the lower electrode 613, respectively. The lower electrode 613 functions as the anode, and the upper electrode 617 functions as the cathode. ru.

[0421] Furthermore, the EL layer 616 can be coated using a deposition method with a deposition mask, an inkjet method, or a spin coat. It is formed by various methods such as the law. In addition, the material that constitutes the EL layer 616 is low It may be a molecular compound or a polymeric compound (including oligomers and dendrimers).

[0422] Furthermore, the lower electrode 613, the EL layer 616, and the upper electrode 617 contribute to the light-emitting element 618. The light-emitting element 618 is formed. The light-emitting element 618 has the configuration of Embodiments 1 to 3. It is preferable that this is the case. Note that if multiple light-emitting elements are formed in the pixel portion, then Embodiments 1 to This includes both the light-emitting element described in Embodiment 3 and light-emitting elements having other configurations. You can.

[0423] Furthermore, by bonding the sealing substrate 604 to the element substrate 610 with the sealing material 605, A light-emitting element is placed in the region 607 surrounded by the element substrate 610, the sealing substrate 604, and the sealing material 605. The structure is equipped with child 618. Furthermore, the area 607 is filled with filler material. In addition to cases where an inert gas (such as nitrogen or argon) is filled, it is also used in sealant 605. In some cases, it may be filled with UV-curing resin or thermosetting resin, for example, PVC ( Polyvinyl chloride resins, acrylic resins, polyimide resins, epoxy resins, Silicone resin, PVB (polyvinyl butyral) resin, or EVA (ethylene vinyl A resin (such as a luacetate) can be used. A recess is formed in the sealing substrate, and a desiccant is placed therein. Providing this feature can suppress deterioration due to moisture, making it a desirable configuration.

[0424] Furthermore, the optical element 621 is positioned below the sealing substrate 604 so as to overlap with the light-emitting element 618. It is provided therein. Furthermore, a light-shielding layer 622 is provided below the sealing substrate 604. Optical element 621 and the light-shielding layer 622 are the optical element and the light-shielding layer shown in Embodiment 3, respectively. A similar configuration would suffice.

[0425] Furthermore, it is preferable to use epoxy resin or glass frit for the sealant 605. Furthermore, it is desirable that these materials be as impermeable to moisture and oxygen as possible. In addition, as materials used for the sealing substrate 604, glass substrates and quartz substrates are also available, as well as FRP (Fiber Reinforced Plastic). Reinforced Plastics), PVF (Polyvinyl Fluoride), Poly A plastic substrate made of ester or acrylic can be used.

[0426] As described above, the light-emitting element and optical element described in Embodiments 1 to 3 are A display device can be obtained.

[0427] <Example of display device configuration 2> Next, another example of a display device will be explained using Figures 12(A)(B) and 13. Figures 12(A)(B) and 13 are cross-sectional views of a display device according to one embodiment of the present invention. .

[0428] Figure 12(A) shows the substrate 1001, the underlayer insulating film 1002, the gate insulating film 1003, and the gate Electrodes 1006, 1007, 1008, first interlayer insulating film 1020, second interlayer insulating film 10 21, peripheral portion 1042, pixel portion 1040, drive 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, the sealing layer 1029, the sealing substrate 1031, the sealing material 1032, etc. are shown in the diagram. .

[0429] Furthermore, in Figure 12(A), as an example of an optical element, a colored layer (red colored layer 1034R) is shown. A green colored layer 1034G and a blue colored layer 1034B are provided on a transparent substrate 1033. A light-shielding layer 1035 may also be provided. A transparent material having a colored layer and a light-shielding layer. The substrate 1033 is aligned and fixed to the substrate 1001. Note that the colored layer and the light-shielding layer are also included. It is covered with an overcoat layer 1036. Also, in Figure 12(A), the colored layer Since light passing through it is red, green, and blue, an image can be represented using pixels of these three colors.

[0430] Figure 12(B) shows an example of an optical element, with a colored layer (red colored layer 1034R, green colored layer The colored layer 1034G and the blue colored layer 1034B are connected to the gate insulating film 1003 and the first interlayer insulating film. An example of formation between film 1020 and the substrate 1001 is shown. In this way, the colored layer is sealed with the substrate 1001. It may also be provided between the substrates 1031.

[0431] Figure 13 shows an example of an optical element, with a colored layer (red colored layer 1034R, green colored layer) 1034G, the blue colored layer 1034B) is connected to the first interlayer insulating film 1020 and the second interlayer insulating film This shows an example of formation between 1021 and substrate 1001. Thus, the colored layer is formed between substrate 1001 and the sealing group It may also be provided between the plates 1031.

[0432] Furthermore, in the display device described above, the side of the substrate 1001 on which the transistor is formed Although a display device with a light extraction structure (bottom emission type) was used, on the encapsulating substrate 1031 side It can also be used as a display device with a structure that extracts light (top emission type).

[0433] <Example of display device configuration 3> An example of a cross-sectional view of a top-emission type display device is shown in Figure 14(A)(B). Figure 14 Figures (A) and (B) are cross-sectional views illustrating a display device according to one embodiment of the present invention, and Figure 12(A) and (B) are cross-sectional views illustrating a display device according to one embodiment of the present invention. ) and the drive circuit section 1041, peripheral section 1042, etc. shown in Figure 13 are omitted for illustrative purposes.

[0434] In this case, the substrate 1001 can be a substrate that does not transmit light. Until the connecting electrode that connects to the anode of the optical element is fabricated, it will be a bottom-emission type display device. It is formed in the same manner as above. Then, the third interlayer insulating film 1037 is formed so as to cover the electrode 1022. This insulating film may also play a planarization role. The third interlayer insulating film 1037 is In addition to materials similar to those used for the interlayer insulating film in step 2, it can be formed using a variety of other materials.

[0435] The lower electrodes 1024R, 1024G, and 1024B of the light-emitting element are referred to as anodes here, but the negative electrodes are not. It can also be a pole. Also, a top-emission type display like Figure 14(A)(B) is also acceptable. If it is a device, the lower electrodes 1024R, 1024G, and 1024B have the function of reflecting light. It is preferable to do so. Also, an upper electrode 1026 is provided on the EL layer 1028. Electrode 1026 has the function of reflecting light and the function of transmitting light, and lower electrode 1024R, 10 A microcavity structure is employed between 24G, 1024B and the upper electrode 1026. It is preferable to increase the light intensity at a specific wavelength.

[0436] In the top emission structure shown in Figure 14(A), the colored layer (red colored layer 1034) Encapsulation substrate 1031 provided with R, a green colored layer 1034G, and a blue colored layer 1034B) Sealing can be performed using this method. The sealing substrate 1031 is positioned between pixels. A light layer 1035 may be provided. Furthermore, if a light-transmitting substrate is used for the sealing substrate 1031, It is suitable.

[0437] Furthermore, in Figure 14(A), multiple light-emitting elements are shown, and each of these multiple light-emitting elements is colored. While a configuration with layers has been given as an example, the system is not limited to this. For example, as shown in Figure 14(B) Without providing a green colored layer, a red colored layer 1034R and a blue colored layer 1034B are provided. Alternatively, a configuration that displays in full color using three colors—red, green, and blue—is also possible, as shown in Figure 14(A). As shown above, when a light-emitting element is provided and a colored layer is provided on each of the light-emitting elements, external light reflection This has the effect of being able to suppress it. On the other hand, as shown in Figure 14(B), the light-emitting element and the green If a configuration is used in which a red colored layer and a blue colored layer are provided without a colored layer, then green Because there is little energy loss from the light-emitting element, power consumption can be reduced. It produces the desired effect.

[0438] <Example of display device configuration 4> The display device described above has a configuration having three subpixels (red, green, and blue), A structure having subpixels of four colors (red, green, blue, yellow, or red, green, blue, white) It may be considered as a component. Figures 15 to 17 show the lower electrodes 1024R, 1024G, 1024B, And the configuration of a display device having 1024Y. Figures 15(A)(B) and 16 show the tra A structure (bottom emission type) that extracts light from the substrate 1001 where the inverter is formed. This is a display device, and Figures 17(A) and 17(B) show a structure that extracts light from the encapsulated substrate 1031 side. It is a top-emission type display device.

[0439] Figure 15(A) shows the optical elements (colored layer 1034R, colored layer 1034G, colored layer 1034B This is an example of a display device in which a colored layer (1034Y) is provided on a transparent substrate (1033). Also, see Figure 15. (B) is an optical element (colored layer 1034R, colored layer 1034G, colored layer 1034B, colored layer An indication of forming 1034Y) between the gate insulating film 1003 and the first interlayer insulating film 1020. This is an example of the apparatus. Also, Figure 16 shows the optical elements (colored layer 1034R, colored layer 1034G, The color layer 1034B and the colored layer 1034Y are connected to the first interlayer insulating film 1020 and the second interlayer insulating film 1 This is an example of a display device formed between 021 and 021.

[0440] Colored layer 1034R transmits red light, colored layer 1034G transmits green light, colored layer 1034B has the function of transmitting blue light. In addition, the colored layer 1034Y transmits yellow light. A function that allows light to pass through, or a function that transmits multiple colors selected from blue, green, yellow, and red. The colored layer 1034Y transmits multiple lights selected from blue, green, yellow, and red. When it has the function of being yellow, the light transmitted through the colored layer 1034Y may be white. Because light-emitting elements that emit white light have high luminous efficiency, a display having a colored layer 1034Y The device can reduce power consumption.

[0441] Furthermore, in the top-emission type display device shown in Figure 17, the lower electrode 1024Y In the light-emitting element having the same characteristics as the display device in Figure 14(A), the upper electrode 1026 A configuration having a microcavity structure in between is preferred. Also, the display device in Figure 17(A) So, the colored layers (red colored layer 1034R, green colored layer 1034G, blue colored layer 103 The sealing can be performed with a sealing substrate 1031 having 4B and a yellow colored layer 1034Y). ru.

[0442] The emission exhibited through the microcavity and the yellow colored layer 1034Y is in the yellow region. The emission will have an emission spectrum in the region. Since yellow is a color with high visual sensitivity, yellow emission will occur. A light-emitting element exhibiting this characteristic has high luminous efficiency. That is, a display device having the configuration shown in Figure 17(A) is This can reduce power consumption.

[0443] Furthermore, in Figure 17(A), multiple light-emitting elements are shown, and each of these light-emitting elements is colored. While a configuration with layers has been given as an example, the system is not limited to this. For example, as shown in Figure 17(B) Without providing a yellow colored layer, a red colored layer 1034R, a green colored layer 1034G, and a blue colored layer are provided. A colored layer 1034B is provided, and four colors are used: red, green, blue, and yellow, or red, green, blue, and white. A configuration that enables full-color display may also be used. As shown in Figure 17(A), a light-emitting element and the When a colored layer is provided on each optical element, it has the effect of suppressing external light reflection. It performs. On the other hand, as shown in Figure 17(B), the light-emitting element and the red without a yellow colored layer are used. If the configuration includes a colored layer, a green colored layer, and a blue colored layer, then yellow or white Because there is little energy loss from the light-emitting element, power consumption can be reduced. It produces the desired effect.

[0444] <Example of display device configuration 5> Next, another embodiment of the present invention is shown in Figure 18. Figure 18 is a reference to Figure 11(A This is a cross-sectional view taken along the dashed lines AB and CD of the ) in Figure 18. Therefore, parts having the same function as those shown in Figure 11(B) are denoted with the same reference numerals, and their details I will omit the detailed explanation.

[0445] The display device 600 shown in Figure 18 comprises an element substrate 610, a sealing substrate 604, and a sealing material 60 The region 607 enclosed by 5 has sealing layers 607a, 607b, and 607c. One or more of the sealing layers 607a, 607b, and 607c may include, for example, For example, PVC (polyvinyl chloride) resin, acrylic resin, polyimide resin, etc. Poxy resins, silicone resins, PVB (polyvinyl butyral) resins, or EVA Resins such as (ethylene vinyl acetate) resins can be used. Also, silica oxide Silicon oxide nitride, silicon nitride, silicon nitride, aluminum oxide, aluminum nitride Inorganic materials such as titanium may also be used. Sealing layer 607a, sealing layer 607b, sealing layer 607 By forming c, the degradation of the light-emitting element 618 due to impurities such as water can be suppressed. Preferred. When forming sealing layer 607a, sealing layer 607b, and sealing layer 607c, It is not necessary to provide the 605 material.

[0446] Furthermore, sealing layers 607a, 607b, and 607c may be one or two of each. It may be the case that four or more sealing layers are formed. By making the sealing layers multilayered, water These impurities can penetrate from outside the display device 600 to the light-emitting element 618 inside the display device. This is preferable because it can effectively prevent this. Furthermore, if the sealing layer is multilayered, the resin and inorganic material A preferred configuration involves layering the materials.

[0447] <Example of display device configuration 6> Furthermore, the display devices shown in Configuration Examples 1 to 4 of this embodiment have optical elements. Although the above configuration has been illustrated, in one aspect of the present invention, optical elements may not be provided.

[0448] The display device shown in Figures 19(A) and (B) has a structure that extracts light from the encapsulated substrate 1031 side. This is a display device of the luminescent type. Figure 19(A) shows the luminescent layer 1028R and the luminescent layer 1 This is an example of a display device having 028G and a light-emitting layer 1028B. Also, Figure 19(B) shows A table having a light 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, and the light-emitting layer 1028G emits green light. The light-emitting layer 1028B has the function of emitting blue light. The light-emitting layer 1028Y emits yellow light. A function that emits light, or a function that emits multiple lights selected from blue, green, and red. It has. The light emitted by the light-emitting layer 1028Y may be white. Yellow or white Because the light-emitting element has high luminous efficiency, a display device having the light-emitting layer 1028Y is It can reduce power consumption.

[0450] The display devices shown in Figures 19(A) and 19(B) include an EL layer that emits light of different colors. Since it is contained within the pixel, it is not necessary to provide a colored layer that acts as an optical element.

[0451] Furthermore, the sealing layer 1029 may be made of, for example, PVC (polyvinyl chloride) resin, acrylic Polyimide resins, epoxy resins, silicone resins, PVB (polyvinyl blue resin) Using resins such as ethylene vinyl acetate (EVA) resin or ethylene vinyl acetate resin. It is possible to do this. Also, silicon oxide, silicon oxide nitride, silicon oxide nitride, silicon nitride Inorganic materials such as aluminum oxide and aluminum nitride may also be used. The sealing layer 1029 Forming it this way is preferable because it can suppress the deterioration of the light-emitting element due to impurities such as water.

[0452] Furthermore, the sealing layer 1029 may consist of one or two of any four or more sealing layers. A layer may be formed. By making the sealing layer multilayered, impurities such as water can enter the outside of the display device. This is preferable because it can effectively prevent penetration into the interior of the display device. In the case of a multilayer structure, a preferred configuration is one in which resin and inorganic material are laminated together.

[0453] Furthermore, the encapsulating substrate 1031 only needs to have a function to protect 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 within this embodiment. They can be combined.

[0455] (Embodiment 5) In this embodiment, a display device having an light-emitting element according to one aspect of the present invention is shown in Figures 20 to We will explain using Figure 22.

[0456] Figure 20(A) is a block diagram illustrating a display device according to one embodiment of the present invention, and Figure 2 Figure 0(B) is a circuit diagram illustrating a pixel circuit in a display device according to one aspect of the present invention.

[0457] <Explanation regarding display devices> The display device shown in Figure 20(A) has a region having pixels of the display element (hereinafter referred to as the pixel portion 802 and ( ) and a circuit section ( ) which is located outside the pixel section 802 and has a circuit for driving the pixels. Hereinafter referred to as the drive circuit section 804, and a circuit having a function to protect the element (hereinafter referred to as the protection circuit 804) It has a (6) and a terminal section 807. Note that the protection circuit 806 is not provided. That's fine.

[0458] Part or all of the drive circuit section 804 is formed on the same substrate as the pixel section 802. This is desirable. This allows for a reduction in the number of components and terminals. Drive circuit section 804 If part or all of it is not formed on the same substrate as the pixel section 802, the drive cycle Part or all of road section 804 is COG or TAB (Tape Automated B It can be implemented by (onding).

[0459] The pixel section 802 is arranged in X rows (where X is a natural number greater than or equal to 2) and Y columns (where Y is a natural number greater than or equal to 2). It has a circuit for driving multiple display elements (hereinafter referred to as the pixel circuit 801), and the drive cycle The path section 804 is a circuit that outputs a signal (scan signal) for selecting pixels (hereinafter referred to as the scan line drive circuit). 804a) is used to supply signals (data signals) for driving the pixel display elements. It has a drive circuit such as the signal line drive circuit 804b.

[0460] The scan line driving circuit 804a includes a shift register, etc. The scan line driving circuit 804a is A signal to drive the shift register is input via terminal 807, and the signal is output. For example, the scan line drive circuit 804a receives a start pulse signal, a clock signal, etc. The scan line drive circuit 804a outputs a pulse signal. The scanning signal is supplied to the wiring (and It has the function of controlling the potential of the scan lines (referred to as GL_1 to GL_X). Multiple drive circuits 804a are provided, and the scan line GL_1 is driven by multiple scan line drive circuits 804a. The path to GL_X may be divided and controlled. Alternatively, the scan line drive circuit 804a may use an initialization signal. It has the function of supplying, however, the scan line drive circuit 80 4a can also supply another signal.

[0461] The signal line drive circuit 804b includes a shift register, etc. The signal line drive circuit 804b is Through terminal 807, in addition to signals for driving the shift register, the data signals are generated. A signal (image signal) is input. The signal line drive circuit 804b uses the image signal to drive the pixel circuit It has the function of generating data signals to be written to 801. In addition, the signal line drive circuit 804b The data signal is transmitted according to the pulse signal obtained by inputting the start pulse, clock signal, etc. It has the function of controlling the output of the signal. In addition, the signal line drive circuit 804b is provided with a data signal. It has the function of controlling the potential of the wiring (hereinafter referred to as data lines DL_1 to DL_Y). Alternatively, the signal line drive circuit 804b may have the function of supplying an initialization signal. However, it is not limited to this, and the signal line drive circuit 804b may also supply other signals. It is possible.

[0462] The signal line drive circuit 804b is configured using, for example, multiple analog switches. The signal line drive circuit 804b sequentially turns on multiple analog switches, The image signal can be time-divided and output as a data signal. It can also use shift registers, etc. The signal line drive circuit 804b may be constructed using this.

[0463] Each of the multiple pixel circuits 801 receives a scan signal from one of the multiple scan lines GL. A pulse signal is input via one of several data lines DL to which a data signal is supplied. A data signal is input. In addition, each of the multiple pixel circuits 801 is a scan line drive circuit 804a controls the writing and retention of data in the data signal. For example, m rows and n columns. The pixel circuit 801 of the eye is driven by a scan line drive circuit via the scan line GL_m (where m is a natural number less than or equal to X). A pulse signal is input from 804a, and the data line DL_n( A data signal is input from the signal line drive circuit 804b via n (where n is a natural number less than or equal to Y).

[0464] The ...

Claims

1. A hole injection layer and an emitting layer are provided between a pair of electrodes. The hole injection layer has an electron-accepting material, The light-emitting layer comprises a phosphorescent material and a host material. The host material has a π-electron-deficient heteroaromatic ring skeleton, The host material has at least one of a π-electron-rich heteroaromatic ring skeleton or an aromatic amine skeleton. The LUMO level of the phosphorescent material is lower than the LUMO level of the host material. The energy difference between the LUMO level and the HOMO level of the phosphorescent material is greater than the energy difference between the LUMO level and the HOMO level of the host material. A light-emitting element in which the energy difference between the LUMO level of the phosphorescent material and the HOMO level of the host material is greater than or equal to the transition energy calculated from the absorption edge in the absorption spectrum of the phosphorescent material.

2. A hole injection layer and an emitting layer are provided between a pair of electrodes. The hole injection layer has an electron-accepting material, The light-emitting layer comprises a phosphorescent material and a host material. The host material has a π-electron-deficient heteroaromatic ring skeleton, The host material has at least one of a π-electron-rich heteroaromatic ring skeleton or an aromatic amine skeleton. The LUMO level of the phosphorescent material is lower than the LUMO level of the host material. The energy difference between the LUMO level and the HOMO level of the phosphorescent material is greater than the energy difference between the LUMO level and the HOMO level of the host material. A light-emitting element in which the energy difference between the LUMO level of the phosphorescent material and the HOMO level of the host material is greater than or equal to the energy of the light emitted by the phosphorescent material.

3. In claim 2, The energy of the light emitted by the phosphorescent material is derived from the shortest wavelength emission peak (maximum value or shoulder) of the emission spectrum, as described in the light-emitting element.

4. In claim 2, The energy of the light emitted by the phosphorescent material is derived from the wavelength of the shortest rising edge of the emission spectrum.

5. In any one of claims 1 to 4, A light-emitting element wherein the energy difference between the LUMO level and the HOMO level of the phosphorescent material is 0.4 eV or greater than the transition energy calculated from the absorption edge in the absorption spectrum of the phosphorescent material.

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

7. In any one of claims 1 to 6, The host material is a light-emitting element that has the function of supplying excitation energy to the phosphorescent material.

8. In any one of claims 1 to 7, The phosphorescent material is a light-emitting element comprising ruthenium, rhodium, palladium, osmium, iridium, and platinum.

9. In any one of claims 1 to 8, A light-emitting element in which the phosphorescent material exhibits light emission.

10. In any one of claims 1 to 9, The host material is a light-emitting element in which the difference between the singlet excitation energy level and the triplet excitation energy level is greater than 0 eV and 0.2 eV or less.

11. In any one of claims 1 to 10, The host material is a light-emitting element that exhibits thermally activated delayed fluorescence at room temperature.

12. In any one of claims 1 to 11, The aforementioned electron-accepting material is an organic compound having a halogen group or a cyano group, in the light-emitting element.

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

14. A light-emitting element according to any one of claims 1 to 13, A color filter or at least one transistor, A display device.

15. The display device according to claim 14, At least one of the housing or touch sensors, A powerful electronic device.

16. A light-emitting element according to any one of claims 1 to 13, At least one of the housing or touch sensors, A lighting device having the following features.

Images