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

Abstract

To provide a light-emitting element having low driving voltage and high emission efficiency.SOLUTION: In the light-emitting element, the guest material and the host material form an exciplex. The guest material has a function of converting triplet excitation energy into light emission. Light emission from the light-emitting layer includes light emission from the guest material and light emission from the exciplex, and the proportion of the light emission from the exciplex to the light emission from the light-emitting layer is higher than 0% and lower than or equal to 60%. 0eV <EG _ em-EEx _ em ≤ 0. 23eV is satisfied where EG _ em is the light emission energy of the guest material and EEx _ em is the light emission energy of the exciplex.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

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

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

[0004] Since the above-mentioned light-emitting element is a self-luminous type, a display device using it has excellent visibility and The display device has the advantages of not requiring a light source and of low power consumption. It also has the advantages of being lightweight and having a high response speed.

[0005] An EL device that uses an organic compound as the luminescent material and contains the luminescent organic compound between a pair of electrodes In the case of a light-emitting element (for example, an organic EL element) having a layer, a voltage is applied between a pair of electrodes. As a result, electrons are injected from the cathode and holes are injected from the anode into the light-emitting EL layer. The injected electrons and holes are then recombined to form a luminescent The organic compound is excited, and light can be emitted from the excited luminescent organic compound. do.

[0006] The types of excited states that organic compounds can form include singlet excited states (S * ) and triplet excitation Condition (T * ) and emission from the singlet excited state is fluorescence, and emission from the triplet excited state is phosphorescence. The statistical generation rate of these light sources in a light-emitting device is S * :T * = Therefore, compared to a light-emitting element using a compound that emits fluorescence (a fluorescent compound), Light-emitting elements that use phosphorescent compounds (phosphorescent compounds) have higher luminous efficiency. Therefore, it is possible to convert the energy of the triplet excited state into light emission. In recent years, development of light-emitting devices using phosphorescent compounds has been actively carried out (see, for example, Patent Document 1). (see).

[0007] The energy required to excite an organic compound is determined by the LUMO and HOM levels of the organic compound. The energy difference depends on the energy difference between the O level and the singlet excited state. In a light-emitting element using a phosphorescent compound, triplet excitation energy corresponds to Therefore, the singlet and triplet excited states formed by organic compounds are When the energy difference between the excited and excited states is large, the energy required to excite the organic compound is The energy of the light is higher than that of the light emission by the amount of energy corresponding to the energy difference. The difference between the energy required to excite an organic compound and the energy of emission is The increase in the driving voltage of the element affects the element characteristics. Therefore, reducing the driving voltage Techniques for achieving this are being explored (see Patent Document 2).

[0008] Furthermore, among light-emitting elements using phosphorescent compounds, light-emitting elements that emit blue light are particularly However, it is difficult to develop stable compounds with high triplet excitation energy levels. Therefore, we are working to develop a phosphorescent compound that has high luminous efficiency and excellent reliability. There is a demand for the development of light-emitting devices with such properties. [Prior art documents] [Patent documents]

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

[0010] Iridium complexes are known as phosphorescent compounds that exhibit high luminous efficiency. As an iridium complex with luminescent energy, a nitrogen-containing five-membered heterocyclic skeleton is used as a ligand. The nitrogen-containing five-membered heterocyclic skeleton has a high triplet excitation energy. However, the electron-accepting property is lower than that of the nitrogen-containing six-membered heterocyclic skeleton. Iridium complexes with heterocyclic skeletons as ligands have high LUMO levels and are well-suited for electron carriers. Therefore, iridium complexes with a nitrogen-containing five-membered heterocyclic skeleton as a ligand are It is difficult to excite the carriers by direct recombination, making it difficult to emit light efficiently. Iridium complexes with nitrogen-containing five-membered heterocyclic skeletons as ligands tend to have high HOMO levels. In addition, they may interact with other compounds with lower LUMO levels to form exciplexes.

[0011] In addition, the nitrogen-containing six-membered heterocyclic skeleton has a high electron-accepting property. Iridium complexes with the ligand have a low LUMO level and are easy to inject electron carriers. Iridium complexes with a nitrogen-containing six-membered heterocyclic skeleton as a ligand have a low LUMO level. , they may interact with other compounds with higher HOMO levels to form exciplexes.

[0012] When an iridium complex forms an exciplex with another compound, the iridium complex emits light. This causes problems such as a decrease in the light emitting efficiency or an increase in the driving voltage of the light emitting element. Therefore, in a light-emitting element using an iridium complex, it is possible to achieve high luminous efficiency and low driving voltage. There is a demand for the development of light-emitting elements that can be driven.

[0013] Therefore, one object of one embodiment of the present invention is to provide a light-emitting element with high emission efficiency. Another embodiment of the present invention is to provide a light-emitting element with reduced power consumption. Another object of the present invention is to provide a light-emitting element with excellent reliability. Another object of one embodiment of the present invention is to provide a novel light-emitting element. Another object of one embodiment of the present invention is to provide a novel light-emitting device. Another object of one embodiment of the present invention is to provide a novel display device.

[0014] Note that the above description of the object does not preclude the existence of other objects. It is not necessary to solve all of these problems. Problems other than those mentioned above can be solved by the description of the specification, etc. It is obvious from the description of the specification, etc. that other problems can be extracted. do. [Means for solving the problem]

[0015] One embodiment of the present invention is a light-emitting element having a light-emitting layer, in which the light-emitting layer contains a first organic compound and and a second organic compound, wherein one of the first organic compound and the second organic compound is The first organic compound and the second organic compound have a LUMO level equal to or higher than the LUMO level of the other. and the HOMO level of the first organic compound and the second organic compound is higher than or equal to the HOMO level of the other of the first organic compound and the second organic compound. a first organic compound and a second organic compound forming a first exciplex; The first organic compound is capable of converting triplet excitation energy into luminescence. The light emitted from the light-emitting layer is a combination of the light emitted from the first organic compound and the light emitted from the first excitation light source. The light emitted by the first exciplex is compared with the light emitted by the light-emitting layer. The light emitting element has a light ratio greater than 0% and not greater than 60%.

[0016] Another embodiment of the present invention is a light-emitting element having a light-emitting layer, in which the light-emitting layer includes a first and a second organic compound, One of the first and second organic compounds has a LUMO level higher than or equal to the LUMO level of the other of the first and second organic compounds. and the HOMO level of the first organic compound and the HOMO level of the second organic compound are higher than or equal to the HOMO level of the other of the first organic compound and the second organic compound. and the first organic compound and the second organic compound form a first exciplex. The first organic compound converts triplet excitation energy into luminescence. The first organic compound has a function of being able to emit light with an energy of E G_em and The luminescence energy of the first exciplex is E Ex_em When <E G _em -E Ex_em The light-emitting device satisfies the relational expression of ≦0.23 eV.

[0017] In the above configuration, E G_em is the shortest emission spectrum exhibited by the first organic compound. It is preferable that the energy be calculated from the wavelength of the emission peak on the wavelength side.

[0018] Another embodiment of the present invention is a light-emitting element having a light-emitting layer, in which the light-emitting layer includes a first and a second organic compound, One of the first and second organic compounds has a LUMO level higher than or equal to the LUMO level of the other of the first and second organic compounds. and the HOMO level of the first organic compound and the HOMO level of the second organic compound are higher than or equal to the HOMO level of the other of the first organic compound and the second organic compound. and the first organic compound and the second organic compound form a first exciplex. The first organic compound converts triplet excitation energy into luminescence. and the absorption edge of the absorption spectrum of the first organic compound is calculated from the absorption edge of the absorption spectrum of the first organic compound. transition energy E G_abs and the luminescence energy of the first exciplex is E Ex _em When <E G_abs -E Ex_em Satisfies the relational expression ≦0.30 eV It is a light-emitting element.

[0019] In each of the above configurations, E Ex_em is the most prominent part of the emission spectrum exhibited by the first exciplex. The energy is preferably calculated from the wavelength of the emission peak on the short wavelength side.

[0020] Another embodiment of the present invention is a light-emitting element having a light-emitting layer, in which the light-emitting layer includes a first and a second organic compound, One of the first and second organic compounds has a LUMO level higher than or equal to the LUMO level of the other of the first and second organic compounds. and the HOMO level of the first organic compound and the HOMO level of the second organic compound are higher than or equal to the HOMO level of the other of the first organic compound and the second organic compound. The first organic compound has a HOMO level of 1000 nm, and the first organic compound converts triplet excitation energy into luminescence. and a transition calculated from the absorption edge of the absorption spectrum of the first organic compound. Energy E G_abs and HO of one of the first organic compound and the second organic compound. The energy of the MO level and the other LUMO level of the first organic compound and the second organic compound -Difference is ΔE Ex When <E G_abs -ΔE Ex ≦0.23 eV It is a light-emitting element that satisfies the

[0021] In the above structure, the first organic compound and the second organic compound form a first exciplex. It is preferable that the combination is such that

[0022] In each of the above structures, the lowest excited triplet energy level of the second organic compound is the lowest excited triplet energy level of the first organic compound is equal to or higher than the lowest excited triplet energy level of the second organic compound; The excited triplet energy level is equal to or greater than the lowest excited triplet energy level of the first exciplex. This is preferable.

[0023] In each of the above structures, the light-emitting layer further contains a third organic compound, and the second organic compound One of the compound and the third organic compound is the other of the second organic compound and the third organic compound. a first organic compound and a third organic compound having a LUMO level equal to or higher than the LUMO level of the first organic compound; a second organic compound and a third organic compound, each of which has a HOMO level equal to or higher than the HOMO level of the other organic compound; A combination that forms a second exciplex with the organic compound is preferred.

[0024] In the above structure, the lowest excited triplet energy level of the second organic compound and the The lowest excited triplet energy level of the organic compound in 3 is the lowest excited triplet energy level of the second exciplex. The lowest excited triplet energy level of the second exciplex is equal to or higher than the lowest excited triplet energy level of the first exciplex. It is preferable that the energy level is equal to or higher than the lowest excited triplet energy level of the organic compound.

[0025] In each of the above structures, either the second organic compound or the third organic compound is a hole The other of the second organic compound and the third organic compound has a function of transporting Preferably, the second organic compound or the second organic compound has a function of transporting electrons. One of the third organic compounds has a π-electron-rich heteroaromatic ring skeleton or an aromatic amine skeleton. the other of the second organic compound or the third organic compound is a π-electron-deficient complex It is preferable that the alkylene compound has an aromatic ring skeleton.

[0026] In each of the above structures, the light emitted by the light-emitting layer is light emitted by the first organic compound, and luminescence exhibited by the first exciplex, and the luminescence exhibited by the luminescent layer has an luminescence intensity of 1% or less. It is preferable that the time for which the light emission component becomes 37 μs or less.

[0027] In each of the above structures, the first organic compound preferably contains iridium. The first organic compound has a ligand that coordinates with iridium, and the ligand is a nitrogen-containing five-membered complex. Preferably, the second organic compound has a π-electron-deficient heteroaromatic ring skeleton. It is preferable that the

[0028] Another embodiment of the present invention is a light-emitting element having any of the above structures, a color filter or a transistor, and a light-emitting element. and at least one of a first transistor and a second transistor. The electronic device includes the display device and at least one of a housing and a touch sensor. Another embodiment of the present invention is a light-emitting element having any of the above structures, a housing, or a touch sensor. Another embodiment of the present invention is a lighting device having a light-emitting element. Not only optical devices but also electronic devices having light-emitting devices are included in the category. The light-emitting device in this context refers to an image display device or a light source (including a lighting device). Optical element connector, such as FPC (Flexible Printed Circuit) t), TCP (Tape Carrier Package) mounted display module module, a display module with a printed wiring board at the end of the TCP, or a light-emitting element with C Display with IC (Integrated Circuit) directly mounted using OG (Chip On Glass) method The module may also be included in the light emitting device. [Effects of the Invention]

[0029] According to one embodiment of the present invention, a light-emitting element with high emission efficiency can be provided. According to one embodiment of the present invention, a light-emitting element with reduced power consumption can be provided. According to one embodiment of the present invention, a light-emitting element with excellent reliability can be provided. According to one embodiment of the present invention, a novel light-emitting element can be provided. According to one embodiment of the present invention, a novel light-emitting device can be provided. A display device can be provided.

[0030] The description of these effects does not preclude the existence of other effects. It is not necessary to have all of these effects. Effects other than these may be included in the description. It is obvious from the description of the specification, drawings, claims, etc. From this, it is possible to extract other effects. [Brief explanation of the drawings]

[0031] [Figure 1] 1A and 1B are schematic cross-sectional views of a light-emitting element according to one embodiment of the present invention. [Figure 2] 1A and 1B are schematic cross-sectional views of a light-emitting layer of a light-emitting element of one embodiment of the present invention and a diagram illustrating the correlation between energy levels. [Figure 3] 1A and 1B are schematic cross-sectional views of a light-emitting layer of a light-emitting element of one embodiment of the present invention and a diagram illustrating the correlation between energy levels. [Figure 4] 1A and 1B are diagrams illustrating the correlation of energy levels of a light-emitting layer of a light-emitting element according to one embodiment of the present invention. [Figure 5] 1A and 1B are schematic cross-sectional views of a light-emitting element according to one embodiment of the present invention. [Figure 6] 1A and 1B are schematic cross-sectional views of a light-emitting element according to one embodiment of the present invention. [Figure 7] 1A and 1B are schematic cross-sectional views of a light-emitting element according to one embodiment of the present invention. [Figure 8] 1A and 1B are a top view and a cross-sectional view schematic diagram illustrating a display device of one embodiment of the present invention. [Figure 9] 1A and 1B are schematic cross-sectional views illustrating a display device according to one embodiment of the present invention. [Figure 10] 1A and 1B are schematic cross-sectional views illustrating a display device according to one embodiment of the present invention. [Figure 11] FIG. 1 is a perspective view illustrating a display module of one embodiment of the present invention. [Figure 12] 1A to 1C illustrate electronic devices of one embodiment of the present invention. [Figure 13] FIG. 1 is a perspective view illustrating a display device according to one embodiment of the present invention. [Figure 14] 1A to 1C illustrate a lighting device according to one embodiment of the present invention. [Figure 15] FIG. 10 is a graph showing luminance-current density characteristics of a light-emitting element according to an example. [Figure 16] FIG. 10 is a graph showing luminance-voltage characteristics of a light-emitting element according to an example. [Figure 17] FIG. 10 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 18] FIG. 10 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 19] 10A and 10B are graphs illustrating electroluminescence spectra of light-emitting elements according to Examples. [Figure 20] FIG. 10 is a diagram illustrating the emission spectrum of a thin film according to an example. [Figure 21] FIG. 10 is a diagram illustrating the emission spectrum of a thin film according to an example. [Figure 22] FIG. 10 is a diagram illustrating the emission spectrum of a thin film according to an example. [Figure 23] FIG. 10 is a diagram illustrating the emission spectrum of a thin film according to an example. [Figure 24] FIG. 10 is a diagram illustrating the emission spectrum of a thin film according to an example. [Figure 25] FIG. 10 is a diagram illustrating the emission spectrum of a thin film according to an example. [Figure 26] FIG. 10 is a diagram illustrating the emission spectrum of a thin film according to an example. [Figure 27] FIG. 1 is a graph illustrating the external quantum efficiency versus the light emission ratio of an exciplex according to an example. [Figure 28]FIG. 10 is a diagram illustrating the emission rate of an exciplex versus the energy difference between a guest material and an exciplex, and the external quantum efficiency versus the energy difference between a guest material and an exciplex, according to an example. [Figure 29] FIG. 10 is a diagram illustrating the emission rate of an exciplex versus the energy difference between a guest material and an exciplex, and the external quantum efficiency versus the energy difference between a guest material and an exciplex, according to an example. [Figure 30] FIG. 10 is a diagram illustrating the emission rate of an exciplex versus the energy difference between a guest material and an exciplex, and the external quantum efficiency versus the energy difference between a guest material and an exciplex, according to an example. [Figure 31] FIG. 4 is a diagram illustrating the absorption spectrum of a guest material according to an example. [Figure 32] FIG. 4 is a diagram illustrating the absorption spectrum of a guest material according to an example. [Figure 33] FIG. 4 is a diagram illustrating the absorption spectrum of a guest material according to an example. [Figure 34] FIG. 4 is a diagram illustrating the absorption spectrum of a guest material according to an example. [Figure 35] FIG. 4 is a diagram illustrating the absorption spectrum of a guest material according to an example. [Figure 36] FIG. 10 is a diagram illustrating the emission spectrum of a thin film according to an example. [Figure 37] FIG. 10 is a diagram illustrating the emission spectrum of a thin film according to an example. [Figure 38] FIG. 10 is a diagram illustrating the emission spectrum of a thin film according to an example. [Figure 39] FIG. 10 is a diagram illustrating the emission spectrum of a thin film according to an example. [Figure 40] FIG. 10 is a diagram illustrating the emission spectrum of a thin film according to an example. [Figure 41] FIG. 10 is a diagram illustrating transient light emission characteristics of a thin film according to an embodiment. [Figure 42] FIG. 10 is a diagram illustrating transient light emission characteristics of a thin film according to an embodiment. [Figure 43] FIG. 10 is a diagram illustrating transient light emission characteristics of a thin film according to an embodiment. [Figure 44] FIG. 10 is a diagram illustrating transient light emission characteristics of a thin film according to an embodiment. [Figure 45]FIG. 10 is a diagram illustrating transient light emission characteristics of a thin film according to an embodiment. [Figure 46] FIG. 10 is a diagram illustrating transient light emission characteristics of a thin film according to an embodiment. [Figure 47] FIG. 10 is a diagram illustrating transient light emission characteristics of a thin film according to an embodiment. [Figure 48] FIG. 2 is a graph illustrating the luminescence rate vs. luminescence lifetime of an exciplex and the external quantum efficiency vs. luminescence lifetime according to an example. [Figure 49] FIG. 10 is a diagram illustrating the emission spectrum of a thin film according to an example. [Figure 50] FIG. 10 is a diagram illustrating the emission spectrum of a thin film according to an example. [Figure 51] FIG. 10 is a graph showing luminance-current density characteristics of a light-emitting element according to an example. [Figure 52] FIG. 10 is a graph showing luminance-voltage characteristics of a light-emitting element according to an example. [Figure 53] FIG. 10 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 54] FIG. 10 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 55] 10A and 10B are graphs illustrating electroluminescence spectra of light-emitting elements according to Examples. [Figure 56] FIG. 10 is a diagram illustrating the emission spectrum of a thin film according to an example. [Figure 57] FIG. 10 is a diagram illustrating the emission spectrum of a thin film according to an example. [Figure 58] FIG. 10 is a diagram illustrating the emission spectrum of a thin film according to an example. [Figure 59] FIG. 10 is a diagram illustrating the emission spectrum of a thin film according to an example. [Figure 60] FIG. 10 is a diagram illustrating the emission spectrum of a thin film according to an example. [Figure 61] FIG. 10 is a diagram illustrating the emission spectrum of a thin film according to an example. [Figure 62] FIG. 10 is a diagram illustrating the emission spectrum of a thin film according to an example. [Figure 63] FIG. 1 is a graph illustrating the external quantum efficiency versus the light emission ratio of an exciplex according to an example. [Figure 64]FIG. 1 is a graph illustrating external quantum efficiency versus the energy difference between a guest material and an exciplex according to an embodiment. [Figure 65] FIG. 4 is a diagram illustrating the absorption spectrum of a guest material according to an example. [Figure 66] FIG. 1 is a graph illustrating external quantum efficiency versus the energy difference between a guest material and an exciplex according to an embodiment. [Figure 67] FIG. 1 is a graph illustrating external quantum efficiency versus the energy difference between a guest material and an exciplex according to an embodiment. [Figure 68] FIG. 10 is a diagram illustrating the emission spectrum of a thin film according to an example. [Figure 69] FIG. 10 is a diagram illustrating the emission spectrum of a thin film according to an example. [Figure 70] FIG. 10 is a diagram illustrating the emission spectrum of a thin film according to an example. [Figure 71] FIG. 10 is a diagram illustrating the emission spectrum of a thin film according to an example. [Figure 72] FIG. 10 is a diagram illustrating the emission spectrum of a thin film according to an example. [Figure 73] FIG. 10 is a diagram illustrating transient light emission characteristics of a thin film according to an embodiment. [Figure 74] FIG. 10 is a diagram illustrating transient light emission characteristics of a thin film according to an embodiment. [Figure 75] FIG. 10 is a diagram illustrating transient light emission characteristics of a thin film according to an embodiment. [Figure 76] FIG. 10 is a diagram illustrating transient light emission characteristics of a thin film according to an embodiment. [Figure 77] FIG. 10 is a diagram illustrating transient light emission characteristics of a thin film according to an embodiment. [Figure 78] FIG. 10 is a diagram illustrating transient light emission characteristics of a thin film according to an embodiment. [Figure 79] FIG. 10 is a diagram illustrating transient light emission characteristics of a thin film according to an embodiment. [Figure 80] FIG. 2 is a graph illustrating the luminescence rate vs. luminescence lifetime of an exciplex and the external quantum efficiency vs. luminescence lifetime according to an example. [Figure 81] FIG. 10 is a graph showing luminance-current density characteristics of a light-emitting element according to an example. [Figure 82] FIG. 10 is a graph showing luminance-voltage characteristics of a light-emitting element according to an example. [Figure 83] FIG. 10 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 84] FIG. 10 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 85] 10A and 10B are graphs illustrating electroluminescence spectra of light-emitting elements according to Examples. [Figure 86] FIG. 10 is a diagram illustrating the emission spectrum of a thin film according to an example. [Figure 87] FIG. 10 is a diagram illustrating the emission spectrum of a thin film according to an example. [Figure 88] FIG. 10 is a diagram illustrating the emission spectrum of a thin film according to an example. [Figure 89] FIG. 10 is a diagram illustrating the emission spectrum of a thin film according to an example. [Figure 90] FIG. 10 is a diagram illustrating the emission spectrum of a thin film according to an example. [Figure 91] FIG. 10 is a diagram illustrating the emission spectrum of a thin film according to an example. [Figure 92] FIG. 10 is a diagram illustrating the emission spectrum of a thin film according to an example. [Figure 93] FIG. 1 is a graph illustrating the external quantum efficiency versus the light emission ratio of an exciplex according to an example. [Figure 94] FIG. 4 is a diagram illustrating the absorption spectrum of a guest material according to an example. [Figure 95] FIG. 10 is a diagram illustrating the emission rate of an exciplex versus the energy difference between a guest material and an exciplex, and the external quantum efficiency versus the energy difference between a guest material and an exciplex, according to an example. [Figure 96] FIG. 10 is a diagram illustrating the emission rate of an exciplex versus the energy difference between a guest material and an exciplex, and the external quantum efficiency versus the energy difference between a guest material and an exciplex, according to an example. DETAILED DESCRIPTION OF THE INVENTION

[0032] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the above description, and the embodiments and details thereof may be modified without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited to the embodiments described below. The terms and conditions of the present invention are not to be construed as being limited to the content.

[0033] In addition, the position, size, range, etc. of each component shown in the drawings etc. are not necessarily shown in order to facilitate understanding. It may not represent the actual position, size, range, etc. Therefore, the disclosed invention The position, size, range, etc. are not necessarily limited to those disclosed in the drawings, etc.

[0034] In addition, in this specification, ordinal numbers such as 1st, 2nd, etc. are used for convenience, In some cases, the order of processes or layers may not be indicated. For example, "first" may be replaced with "second" or " can be appropriately replaced with "third" etc. The ordinal numbers used to identify an aspect of the present invention may not match. be.

[0035] In addition, in this specification and the like, when explaining the configuration of the invention using drawings, the same The reference numerals may be commonly used even among different drawings.

[0036] In addition, in this specification and the like, the terms "film" and "layer" are interchangeable. For example, the term "conductive layer" can be changed to the term "conductive film." Alternatively, for example, the term "insulating film" may be changed to "insulating layer" It may be possible to change the term to

[0037] In this specification and the like, the singlet excited state (S * ) is a single atom with excitation energy The S1 level is the lowest singlet excited energy level. , the lowest excited energy level of the singlet state (S1 state). term excited state (T * ) is a triplet state with excitation energy. The lowest triplet excited energy level is the lowest triplet excited state (T1 In this specification, the term "singlet excited state" is used to refer to the excited energy level of the singlet excited state. Even when written as S1 state and singlet excited energy level, Also, the triplet excited state and triplet excited energy level are sometimes used. Even in this case, it may refer to the T1 state and T1 level.

[0038] In this specification and the like, a fluorescent compound is a compound that relaxes from a singlet excited state to a ground state. Phosphorescent compounds are compounds that emit light in the visible light region when excited into a triplet state. It is a compound that emits light in the visible light region at room temperature when it relaxes to the bottom state. A phosphorescent compound is a compound that can convert triplet excitation energy into visible light.

[0039] The phosphorescence energy or triplet excitation energy is the shortest wavelength side of the phosphorescence emission. Derived from the wavelength of the emission peak (including the maximum or shoulder) or the wavelength of the rising edge It should be noted that compounds that do not exhibit phosphorescence at room temperature may exhibit phosphorescence at low temperatures ( For example, in a 10K environment, the time-resolved photoluminescence method can be used to observe the In addition, the emission energy of thermally activated delayed fluorescence is the most Wavelength of the emission peak (including the maximum value or shoulder) on the short wavelength side or rising edge It can be derived from the length.

[0040] In this specification and the like, room temperature refers to a temperature in the range of 0°C or higher and 40°C or lower.

[0041] In this specification, the blue wavelength range is 400 nm or more and less than 490 nm. The blue light emission has at least one emission spectrum peak in the wavelength region. The green wavelength region is 490 nm or more and less than 580 nm, and green light is emitted in this wavelength region. It has at least one emission spectrum peak. The red wavelength region is 580 nm. The red light has at least one emission spectrum in the wavelength range of 680 nm or more and 680 nm or less. It has a peak.

[0042] (Embodiment 1) In this embodiment, a light-emitting element of one embodiment of the present invention will be described below with reference to FIGS. Reveal.

[0043] <Configuration example 1 of light-emitting element> First, the structure of a light-emitting element of one embodiment of the present invention will be described below with reference to FIG.

[0044] FIG. 1 is a schematic cross-sectional view of a light-emitting element 150 according to one embodiment of the present invention.

[0045] The light emitting element 150 has a pair of electrodes (electrode 101 and electrode 102), and The EL layer 100 has at least a light-emitting layer 130. .

[0046] The EL layer 100 shown in FIG. 1 includes a hole injection layer 111, a hole transport layer 121, a light emitting layer 130, and a hole transport layer 131. It has functional layers such as layer 112 , electron transport layer 118 , and electron injection layer 119 .

[0047] In this embodiment, of the pair of electrodes, electrode 101 is an anode, and electrode 1 Although the description will be given assuming that O2 is a cathode, the configuration of the light emitting element 150 is not limited to this. The electrode 101 is the cathode, the electrode 102 is the anode, and the layers between the electrodes are stacked in the reverse order. That is, from the anode side, the hole injection layer 111, the hole transport layer 112, and the light emitting layer 113 may be arranged in this order. The light-emitting layer 130, the electron transport layer 118, and the electron injection layer 119 may be stacked in this order. .

[0048] The configuration of the EL layer 100 is not limited to the configuration shown in FIG. 1. At least one layer selected from the group consisting of the transport layer 112, the electron transport layer 118, and the electron injection layer 119 Alternatively, the EL layer 100 may have a hole or electron injection barrier. reduce, improve hole or electron transport, inhibit hole or electron transport, or or a structure having a functional layer having a function of suppressing a quenching phenomenon due to an electrode. The functional layers may each be a single layer or may be a laminate of multiple layers. It is also possible.

[0049] <Light-emitting mechanism of light-emitting element 1> Next, the light emitting mechanism of the light emitting layer 130 will be described below.

[0050] FIG. 2(A) is a cross-sectional view showing an example of the light-emitting layer 130 shown in FIG. The light-emitting layer 130 shown includes a guest material 131 and a host material 132 .

[0051] In the light-emitting element 150 of one embodiment of the present invention, a pair of electrodes (electrode 101 and electrode 102) By applying a voltage between the cathode and the anode, electrons flow from the cathode and holes flow from the anode. The electrons and holes are then injected into the EL layer 100, causing a current to flow. Excitons are formed by the recombination of carriers (electrons and holes). The ratio of singlet excitons to triplet excitons (hereafter referred to as the exciton generation probability) is statistically The probability of generating singlet excitons is 1:3, which means that the rate of generating singlet excitons is 25%. Since the rate at which triplet excitons are generated is 75%, it is necessary to make triplet excitons contribute to light emission. However, this is important for improving the luminous efficiency of the light-emitting element.

[0052] Therefore, the guest material 131 used in the light-emitting layer 130 is a material having triplet excitation energy Among the luminescent compounds, those that emit phosphorescence are preferred. Compounds capable of emitting triplet excitation energy (hereinafter also referred to as phosphorescent compounds) Therefore, the guest material 131 of the light-emitting element 150 is phosphorescent. In the following description, a phosphorescent compound is preferably used as the guest material 131. The guest material 131 is read as a phosphorescent compound. You can change it.

[0053] In order for phosphorescent compounds to efficiently convert triplet excitation energy into luminescence, heavy metals are required. When the phosphorescent compound contains a heavy metal, spin-orbit interaction (electron spin Intersystem interaction between the singlet and triplet states occurs due to the interaction between the spin angular momentum and the orbital angular momentum. The difference between the singlet ground state and the triplet excited state is promoted, and this facilitates the transition between the singlet ground state and the triplet excited state in phosphorescent compounds. That is, the transition between the singlet ground state and the triplet excited state of the phosphorescent compound is allowed. Since the transition probability increases, the efficiency of the emission and the probability of absorption related to the transition can be increased. For this purpose, it is preferable that the phosphorescent compound contains a metal element that exhibits a large spin-orbit interaction. Specifically, transition metal elements are preferred, and platinum group elements (ruthenium (Ru), rhodium (Ru), etc.) are particularly preferred. Rh, Pd, Os, Ir, or It is preferable to have platinum (Pt), and in particular, by having iridium, it is possible to This is preferable because it can increase the transition probability involved in the direct transition between the excited state and the triplet excited state.

[0054] The excitation energy required to excite an organic compound is determined by the LUMO (Low Molecular Orbital Molecular Orbital) of the organic compound. Lowest Unoccupied Molecular Orbital (Lowest Unoccupied Molecular Orbital) HOMO (Highest Occupied Molecular Orbital) It depends on the energy difference between the highest occupied molecular orbital (HOL) and the electron level, It roughly corresponds to the energy of the singlet excited state. Also, according to Hund's rule, the triplet excited state is Therefore, the guest material 131 is a LUM The energy difference between the O level and the HOMO level (ΔE G ) emits light with lower energy than The ΔE of the guest material 131 G is the emission energy of the guest material 131. (E G_em ), and the transition energy (E G_abs ) is larger than ΔE G equivalent to a large Excitation energy is required, and the driving voltage of the light emitting element 150 increases.

[0055] Therefore, in one aspect of the present invention, ΔE G The guest material 1 has an excitation energy smaller than that of By exciting 31, a light-emitting element that can be driven at a low driving voltage and exhibits highly efficient light emission is provided. In the light-emitting element 150 according to one embodiment of the present invention, a guest material 131 and a host material The material 132 is an exciplex (exciplex, exciplex, or exciplex It is preferable that the combination forms a cyclic ring.

[0056] The combination of the guest material 131 and the host material 132 can form an exciplex. However, it is preferable that one of the compounds has the function of transporting holes (hole transport property). The other is a compound that has the function of transporting electrons (electron transport property). In this case, a donor-acceptor type exciplex is easily formed, and In addition, the combination of the guest material 131 and the host material 132 can form an exciplex. The combination is a combination of a compound having hole transport properties and a compound having electron transport properties. In this case, the carrier balance can be easily controlled by the mixture ratio. In the present invention, the ratio of the compound having hole transporting properties to the compound having electron transporting properties is 1:19 to 19:1 ( In addition, by having this structure, it is possible to easily control the carrier balance. Since the carrier recombination region can be easily controlled, the carrier recombination region can also be easily controlled.

[0057] <Correlation between energy levels> As a combination of materials that efficiently form an exciplex, the guest material 131 and the host One HOMO level of the material 132 is equal to or higher than the other HOMO level, and one LUMO It is preferable that the level is equal to or higher than the other LUMO level.

[0058] The LUMO and HOMO levels of the compounds were determined by cyclic voltammetry (C V) Derived from the electrochemical properties (reduction potential and oxidation potential) of the compound measured by the measurement It is possible.

[0059] For example, the guest material 131 has a hole transporting property and the host material 132 has an electron transporting property. In this case, the HOMO level of the guest material 131 is at the same level as shown in the energy band diagram in Figure 2(B). The HOMO level of the host material 132 is preferably equal to or higher than the HOMO level of the guest material 131. It is preferable that the O level is equal to or higher than the LUMO level of the host material 132. The holes and electrons, which are carriers injected from the electrodes (electrodes 101 and 102), This is preferable because it is easily injected into the guest material 131 and the host material 132.

[0060] In FIG. 2(B), Guest (131) represents the guest material 131, and Hos t(132) represents the host material 132, and Exciplex(136) represents the guest material 13 represents an exciplex 136 formed between 1 and a host material 132, and ΔE G is guest material 131 represents the energy difference between the LUMO level and the HOMO level, and ΔE H1 is the L of the host material 132 represents the energy difference between the UMO level and the HOMO level, and ΔE Ex is the LU of the host material 132 The notation and symbol represent the energy difference between the MO level and the HOMO level of the guest material 131. do.

[0061] In addition, the exciplex 136 formed by the guest material 131 and the host material 132 is The guest material 131 has a HOMO molecular orbital, and the host material 132 has a LUMO molecular orbital. The excitation energy of the exciplex 136 is converted into a valence energy of the host material 13 The energy difference (ΔE Ex ) The energy difference (ΔE) between the LUMO level and the HOMO level of the guest material 131 corresponds to G ) and the energy difference between the LUMO level and the HOMO level of the host material 132 (ΔE H1 )twist Therefore, the guest material 131 and the host material 132 form an exciplex 136. By forming the nucleus, it becomes possible to form an excited state with lower excitation energy. Because it has a lower excitation energy, exciplex 136 can form a stable excited state. This can be done.

[0062] In addition, the energy level of the guest material 131 and the host material 132 in the light-emitting layer 130 is The correlation between the levels is shown in Figure 2(C). The notations and symbols in Figure 2(C) are as follows: be. Guest (131): Guest material 131 (phosphorescent compound) Host (132): Host material 132 ·S G : S1 level of guest material 131 T G : T1 level of guest material 131 ·S H1 : S1 level of the host material 132 T H1 : T1 level of the host material 132 ·S E : S1 level of exciplex 136 T E :T1 level of exciplex 136

[0063] In the light-emitting element of one embodiment of the present invention, the guest material 131 and the host material 132 contained in the light-emitting layer 130 The exciplex 136 is formed with the ion beam material 132. The S1 level (S E ) and excitation T1 level of complex 136 (T E ) are adjacent energy levels (Figure 2(C) See Route E1). Specifically, the S1 level (S E ) and T1 level (T E ) is preferably greater than 0 eV and less than or equal to 0.2 eV, more preferably 0 eV or more and 0.1 eV or less.

[0064] An exciplex is an excited state consisting of two substances. In the case of photoexcitation, the excited state They are formed by the interaction of one substance with another substance in its ground state, and When the two substances that formed the exciplex return to the ground state by emitting light, In the case of electrical excitation, when one of them is excited, it quickly Alternatively, one atom can transfer a hole and the other an electron. They can accept electrons and interact with each other to rapidly form exciplexes. Excited energy levels (S) of the oxidized complex 136. E and T E ) are the respective exciplexes that form 136. The S1 level (S G and S H1 )twist This allows the formation of excited states with lower excitation energy. Therefore, the driving voltage of the light emitting element 150 can be reduced.

[0065] Then, both the singlet and triplet excitation energies of exciplex 136 are excited by The S1 level (S E ) and T1 level (TE ) to guest material 131 (phosphorescent T1 level (T G ), light emission is obtained from the guest material 131 ( See Figure 2(C) Route E2).

[0066] In order to suppress the deactivation of the exciplex 136, the T1 level (T E ) is the T1 level (T H1 ) is preferably lower than the In one embodiment, the triplet excitation energy of exciplex 136 is reversed to singlet excitation energy. No intersystem crossing is required, and the singlet excited energy level (S E ) has a high quantum yield This allows for a wide range of materials to be selected.

[0067] Here, the S1 level of the exciplex 136 formed by the guest material 131 and the host material 132 (S E ) and T1 level (T E ) is the T1 level (T G ) lower than Even if there is an S1 level (S E ) and T1 level (T E ) and guest material 13 T1 level of 1 (T G ) are in close proximity, thermal activation can be used to form the guest material 1 The excitation energy from the exciplex 136 formed between the guest material 131 and the host material 132 is transferred to the guest material 131. This allows for the efficient transfer of energy, and the guest material 131 can emit light efficiently. The present inventors have found that the formation of such an exciplex 136 provides a light-emitting device with a long lifetime. It was also found that this improves reliability.

[0068] Since the guest material 131 is a phosphorescent compound, the light emitted from the guest material 131 is The emission is based on the transition from the triplet excited state of 31 to the ground state, and the absorption of the guest material 131 is The absorption edge of the absorption spectrum is due to the transition from the ground state to the triplet excited state of the guest material 131. The emission of exciplex 136 occurs from the singlet excited state of the exciplex to the singlet The emission is based on the transition to the ground state, and the singlet and triplet excited energy levels of the exciplex The energy levels are adjacent.

[0069] Therefore, the luminescence energy (E G_em ) and exciplex 1 36 luminous energy (E Ex_em ) and are in close proximity, or the guest material 131 The transition energy (E G_abs ) and exciplex 13 The luminescence energy (E Ex_em ) are close to each other. To generate E Ex_em E G_em and E G_abs It can be smaller than From these reasons, specifically, E G_em -E Ex_em is 0e V > 0.23 eV (0 eV <E G_em -E Ex_em ≦0.23 eV), More preferably, it is greater than 0 eV and not greater than 0.18 eV (0 eV <E G_em -E Ex_em ≦0.18 eV). Also, preferably E G_abs -E Ex_em is greater than 0 eV 0.30 eV or less (0 eV <E G_abs -E Ex_em ≦0.30 eV), more preferably Preferably, it is greater than 0 eV and less than 0.25 eV (0 eV <E G_abs -E Ex_em ≦0 0.25eV).

[0070] The excitation energy of the exciplex 136 formed by the guest material 131 and the host material 132 is The energy between the LUMO level of the host material 132 and the HOMO level of the guest material 131 is Energy difference (ΔE Ex ) In the above structure, therefore, the guest material 13 The transition energy (E G_abs ) and the host The energy difference (ΔE E x ) are preferably close to each other. On the other hand, to form an exciplex, ΔE Ex E G_ abs Therefore, it is preferable that E G_abs -ΔE Ex is greater than 0 eV and less than 0.23 eV (0 eV <E G_abs -Δ E Ex ≦0.23 eV), more preferably greater than 0 eV and equal to or less than 0.18 eV (0 eV< E G_abs -ΔE Ex ≦0.18 eV).

[0071] By setting the energy relationship as above, the guest material 131 and the host material 132 The excitation energy can be transferred from the formed exciplex 136 to the guest material 131. Light can be efficiently emitted from the insulating material 131.

[0072] In one embodiment of the present invention, ΔE Ex (ΔEG The excitation energy corresponding to The energy excites exciplex 136, and energy transfer from exciplex 136 To generate an excited state of the guest material 131, a low driving voltage is required to generate a photocatalytic reaction from the guest material 131. Light can be emitted. Also, ΔE G However, the luminescence energy of the guest material 131 is (E G_em ), or the transition energy (E G _abs ) (for example, when the guest material is a blue-emitting material) This aspect of the present invention is particularly beneficial. Specifically, the LUMO level of the guest material 131 and H The energy difference between the OMO level (ΔE G ) in the absorption spectrum of the guest material 131 The transition energy (E G_abs ) it is preferable that it is 0.3 eV or more larger. It is preferable that the difference is 0.4 eV or more. Energy (E G_em ) is E G_abs Since it is equal to or smaller than the guest material The energy difference (ΔE) between the LUMO level and the HOMO level of the material 131 G ) but guest material 13 The luminescence energy (E G_em ) is preferably 0.3 eV or more larger than 0 It is more preferable that the emission energy (E G_em and E Ex _em ) is the emission peak (maximum or shoulder) on the shortest wavelength side of the emission spectrum. It can be derived from the wavelength of the peak or the wavelength of the rising edge.

[0073] The emission wavelength of the guest material 131 becomes shorter, and the emission energy (E G_em ) The larger the energy difference between the LUMO level and the HOMO level of the guest material 131 ( ΔE G ) becomes larger, and accordingly, a larger energy is required to excite the guest material 131. However, in one embodiment of the present invention, the guest material 131 The transition energy (E G_abs ) is ΔE Ex Larger and ΔE Ex +0.23eV or less (ΔE Ex <E G_abs ≦ΔE Ex +0.23eV), then ΔE G ΔE is smaller than Ex degree of energy Since the guest material 131 can be excited by the Therefore, the absorption edge of the guest material 131 can be calculated. Transition energy (E G_abs ) and the LUMO and HOMO levels of the guest material 131. The energy difference (ΔE G ) and the larger the energy difference between In this case, the effect of the light-emitting mechanism of one embodiment of the present invention becomes significant. .

[0074] However, the transition energy calculated from the absorption edge in the absorption spectrum of the guest material 131 is Ghee (E G_abs ) becomes smaller, the luminescence energy (E G_em ) also becomes smaller, so high-energy luminescence such as blue luminescence It becomes difficult to obtain EG_abs and ΔE G The difference between If the amount is too high, it becomes difficult to obtain light emission with high energy such as blue light emission.

[0075] From these results, the energy difference between the LUMO level and the HOMO level of the guest material 131 is (ΔE G ) is the transition energy calculated from the absorption edge in the absorption spectrum of the guest material 131. Energy (E G_abs ), it is preferable that the value is larger in the range of 0.3 eV or more and 0.8 eV or less. It is more preferable that the value is in the range of 0.4 eV or more and 0.8 eV or less, and it is more preferable that the value is in the range of 0.5 eV or more and 0. It is more preferable that the luminescence intensity of the guest material 131 is large within a range of 8 eV or less. Energy (E G_em ) is E G_abs Since it is equal to or smaller than the guest material The energy difference (ΔE) between the LUMO level and the HOMO level of the material 131 G ) is the guest material 13 The luminescence energy (E G_em ) from 0.3 eV to 0.8 eV It is preferable that the value is large, and more preferable that the value is large in the range of 0.4 eV or more and 0.8 eV or less. It is even more preferable if it is greater than 0.5 eV and less than 0.8 eV.

[0076] In order for the guest material 131 to emit light with high emission energy (short wavelength), In this case, it is preferable that the T1 level of the guest material 131 is high. The ligand that coordinates to the heavy metal atom of 1 also preferably has a high T1 level, and A low acceptance and a high LUMO level are preferred.

[0077] The guest material with the above structure is a molecule with a high HOMO level that easily accepts holes. When the guest material 131 has a molecular structure that easily accepts holes, The HOMO level of the material 131 is likely to be higher than the HOMO level of the host material 132. It becomes a match.

[0078] When the guest material 131 has a hole-transporting property and the host material 132 has an electron-transporting property, The appropriate hole trapping makes it possible to easily control the carrier balance in the light-emitting layer. This is desirable as it has the effect of extending the life of the light-emitting device, but the HOMO level of the guest material 131 If it is too high, the above-mentioned ΔE Ex becomes small, and the guest material 131 and the host material 1 The transfer of excitation energy from the exciplex formed with 32 to the guest material 131 becomes difficult. Therefore, the HOMO level of the guest material 131 and the HOMO level of the host material 132 The difference between the energy levels is preferably 0.05 eV or more and 0.4 eV or less. The difference between the LUMO level of 31 and the LUMO level of the host material 132 is preferably 0.05 e V or more, more preferably 0.1 eV or more, and even more preferably 0.2 eV or more By considering such a correlation of energy levels, electron carriers can be transported to the host material13 This is preferable because it is easy to inject into 2.

[0079] In addition, the guest material 131 has an electron transporting property, and the host material 132 has a hole transporting property. In this case, as shown in the energy band diagram of FIG. Preferably, the HOMO level of the material 132 is equal to or higher than the HOMO level of the guest material 131. It is preferable that the LUMO level of the host material 132 is higher than or equal to the LUMO level of the guest material 131. .

[0080] In this case, the appropriate electron traps make it easy to control the carrier balance in the light-emitting layer. This is desirable as it increases the lifetime of the light-emitting device, but the guest material 13 If the LUMO level of 1 is too low, the above-mentioned ΔE Ex becomes small, and exciplex 13 Therefore, it becomes difficult for the excitation energy to be transferred from the guest material 6 to the guest material 131. The difference between the LUMO level of the resist material 131 and the LUMO level of the host material 132 is preferably is 0.05 eV or more and 0.4 eV or less. In addition, the HOMO level of the guest material 131 and The difference between the HOMO level of the host material 132 and the HOMO level of the host material 132 is preferably 0.05 eV or more, and more preferably The electron energy is preferably 0.1 eV or more, and more preferably 0.2 eV or more. By making the energy level correlation, holes are easily injected into the host material 132, which is preferable. It is suitable.

[0081] In addition, the S1 level (S E ) and T1 level (T E ) but guest material 131 T1 level (T G ), part of the excitation energy of exciplex 136 is In some cases, the exciplex 136 emits light without moving to the ion exchange material 131. When the emission of 36 becomes dominant, it becomes difficult to generate an excited state of the guest material 131. Therefore, in order to increase the efficiency of the light emitting element 150, In the light emitting element 150, the light emitted by the exciplex 136 is emitted by the guest material It is preferable that the light emitted by the light-emitting element 150 is smaller than that emitted by the light-emitting element 131. The proportion of light emitted by the exciplex 136 in the light is preferably greater than 0% and less than or equal to 60%. , and more preferably greater than 0% and equal to or less than 40%.

[0082] In addition, when a compound having a heavy atom is used as one of the compounds forming the exciplex, the spin orbit The electron spin angular momentum and orbital angular momentum interact to form a singlet state. Intersystem crossing between the triplet state and the exciplex is promoted. The reverse intersystem crossing from the nucleus to the singlet excited state is promoted, so that the singlet excited state Alternatively, the transition from the triplet excited state to the singlet ground state can be enhanced. To achieve this, one of the compounds forming the exciplex must be It is preferable to have a metal element with a large pin-orbit interaction, and specifically, a transition metal element is preferable. In particular, platinum group elements (ruthenium (Ru), rhodium (Rh), palladium (Pd), It is preferred to have osmium (Os), iridium (Ir), or platinum (Pt). In particular, the presence of iridium enhances the intersystem interaction between the singlet and triplet states of the exciplex. Crossings or transitions can be facilitated.

[0083] When a phosphorescent compound is used as the guest material 131, the T1 level (T G ) is the T1 level of other materials in the light-emitting layer 130 (for example, the T1 level of the host material 132 (T H1 )) is preferably lower than the guest material 131 (phosphorescent compound). The deactivation of the doublet excitation energy is less likely to occur, and light emission from the guest material 131 is efficiently obtained. It is possible.

[0084] Note that exciplexes exist only in excited states, and the excited energy level (S E and TE ) is an energy level that exists only when the exciplex 136 is formed. Therefore, each material (guest material 131 or host material 132) that forms the exciplex 136 ) to the excited state of exciplex 136. Excitation energy levels of the material 131 (S G and T G ) or the excitation of the host material 132 alone Electron energy level (S H1 BiT H1 ) to the excited energy level (S E and T E ) does not transfer excitation energy to the S1 level of exciplex 136. (S E ) and T1 level (T E ) is the T1 level (T G ) lower than Even if there is a problem, it is possible to efficiently extract light from the guest material 131.

[0085] <Energy transfer mechanism> Here, we will explain the factors that govern the intermolecular energy transfer process. -The mechanisms of movement are the Förster mechanism (dipole-dipole interaction) and the Dexter mechanism. Two mechanisms have been proposed: the first excited state (electron exchange interaction) and the second excited state (electron exchange interaction). Regarding the transfer of excitation energy from a material to a second material in the ground state, The energy transfer process between the molecules of the material 2 is explained, but one of them is an exciplex. The same is true in the case of

[0086] <Förster mechanism> In the Förster mechanism, energy transfer does not require direct contact between molecules. Energy transfer occurs through the resonance phenomenon of the dipole vibration of a material and a second material. The first material transfers energy to the second material through the vibrational resonance phenomenon, and the first material is in an excited state. The first material is in the ground state, and the second material in the ground state is in the excited state. rate constant k of the mechanism h*→g is shown in Equation (1).

[0087]

number

[0088] In formula (1), ν represents the frequency, and f' h (ν) is the normalized value of the first material The emission spectrum (or the fluorescence spectrum when discussing energy transfer from the singlet excited state) , and phosphorescence spectrum when discussing energy transfer from triplet excited states), and ε g ( ν) represents the molar extinction coefficient of the second material, N represents Avogadro's number, and n represents the refractive index of the medium. represents the refractive index, R represents the intermolecular distance between the first and second materials, and τ represents the measured excitation represents the lifetime of the state (fluorescence lifetime or phosphorescence lifetime), c represents the speed of light, and φ represents the luminescence quantum yield ( When discussing energy transfer from a singlet excited state, the fluorescence quantum yield is used. When discussing energy transfer from a triplet excited state, the fluorescence quantum yield is used. When discussing energy transfer, it represents the phosphorescence quantum yield, and K 2 is the first material and the second material is a coefficient (0 to 4) that represents the orientation of the transition dipole moment of the The match is K 2 =2 / 3.

[0089] Dexter Mechanism In the Dexter mechanism, the first and second materials overlap at the effective contact distance. approaching each other through the exchange of electrons from the first material in the excited state with those from the second material in the ground state. Energy transfer occurs. The rate constant of the Dexter mechanism is k h*→g is shown in equation (2). vinegar.

[0090]

number

[0091] In equation (2), h is Planck's constant, and K is a constant with the dimension of energy. where ν represents the frequency and f' h (ν) is the normalized emission spectrum of the first material (When discussing energy transfer from the singlet excited state, the fluorescence spectrum is used. When discussing energy transfer from the triplet excited state, the When discussing energy transfer from the fluorine-containing state, it represents the phosphorescence spectrum, and ε' represents the g (ν) is the second represents the normalized absorption spectrum of the material, L represents the effective molecular radius, and R represents the first It represents the intermolecular distance between a material and a second material.

[0092] Here, the energy transfer efficiency φ from the first material to the second material is ET is expressed as formula (3). k r First, we discuss the luminescence process of the material (energy transfer from the singlet excited state). The rate constants are expressed as follows: fluorescence when discussing the energy transfer from the triplet excited state, and phosphorescence when discussing the energy transfer from the triplet excited state. s, k n represents the rate constant of non-radiative processes (thermal deactivation and intersystem crossing) in the second material, and τ is the actual represents the lifetime of the excited state of the first material to be measured.

[0093]

number

[0094] From equation (3), the energy transfer efficiency φ ET To increase the energy transfer rate, Degree constant k h*→g By increasing the rate constant k r +k n (=1 / τ) is relatively You know the smaller the better.

[0095] <Excitation energy transfer to phosphorescent compounds or exciplexes> First, consider the energy transfer via the Förster mechanism. Substituting equation (1) into equation (3), Therefore, in the case of the Förster mechanism, the energy Energy transfer efficiency φ ET is independent of the lifetime τ of the excited state of the first material. Movement efficiency φ ET is the luminescence quantum yield φ (when considering energy transfer from a singlet excited state) is the fluorescence quantum yield, and when discussing energy transfer from triplet excited states, is the phosphorescence quantum yield) It can be said that higher is better.

[0096] In addition, the emission spectrum of the first material (when discussing energy transfer from the singlet excited state) When discussing energy transfer from triplet excited states, the spectrum is fluorescent. the absorption spectrum of the second material (corresponding to the transition from the singlet ground state to the singlet excited state) It is preferable that the overlap with the absorption of the second material is large. Furthermore, the molar absorption coefficient of the second material is also high. This means that the emission spectrum of the first material and the absorption spectrum of the second material are This means that the absorption band of the second material overlaps with the absorption band that appears on the longest wavelength side of the When a phosphorescent compound is used, in addition to the transition from the singlet ground state to the singlet excited state, Transitions from the triplet ground state to the triplet excited state are also allowed. When using the , direct transition from the singlet ground state to the singlet excited state and Since direct transition to the triplet excited state is forbidden, the molar ratio in the second material (exciplex) is The extinction coefficient of the first material is negligible. The excitation energy transfer process from the first material to the second material (exciplex) is negligible.

[0097] Next, consider the energy transfer via the Dexter mechanism. According to equation (2), the rate constant is k h*→g To increase the emission spectrum of the first material (energy from the singlet excited state), When discussing energy transfer, consider the fluorescence spectrum and energy transfer from triplet excited states. the phosphorescence spectrum in the case of the first material) and the absorption spectrum (singlet ground state to singlet excited state It can be seen that the larger the overlap with the absorption corresponding to the transition to the state, the better. The optimization of energy transfer efficiency is achieved by matching the emission spectrum of the first material with the absorption spectrum of the second material. This is realized by the overlap of the absorption band that appears on the longest wavelength side of the spectrum. However, when a phosphorescent compound is used as the second material, the singlet ground state is converted to the singlet excited state. In addition to transitions to the singlet ground state, transitions from the singlet ground state to the triplet excited state are also allowed. When an exciplex is used as the second material, a direct transition from the singlet ground state to the singlet excited state occurs. Since the direct transition from the singlet ground state to the triplet excited state is forbidden, the second The absorption spectrum of the material (exciplex) is negligible. The excitation energy transfer process from the first material to the second material (exciplex) by the mechanism cannot be ignored. Cut.

[0098] Therefore, when a phosphorescent compound is used as the second material, the first material is converted into the second material. For energy transfer to phosphorescent compounds, the Förster mechanism and the Dexter mechanism On the other hand, when an exciplex is used as the second material, energy transfer occurs by both mechanisms. In this case, the energy transfer process from the first material to the second material (exciplex) is Energy transfer by both the Wörster mechanism and the Dexter mechanism does not occur. That is, in the light-emitting element of one embodiment of the present invention, the guest material 131 and the host material 132 Energy transfer occurs from the resulting exciplex 136 to the guest material 131, while the guest No energy transfer will occur from material 131 to exciplex 136.

[0099] In addition, when the direct recombination process of carriers becomes dominant in the guest material 131, The process of forming an exciplex 136 between the material 131 and the host material 132 becomes difficult to occur, and The driving voltage of the optical element 150 increases. The guest material 131 emits light through an energy transfer process (Routes E1 and E2 in Figure 2(C)). To achieve this, the host material 132 and the guest material 131 are preferably The weight ratio of the guest material 131 to the host material is preferably low. The weight ratio of the guest material 131 to the guest material 132 is preferably 0.01 or more and 0.5 or less. , and more preferably 0.05 or more and 0.3 or less.

[0100] In order to suppress deactivation of excitation energy in the light-emitting layer 130, It is preferable that the luminescence lifetime of the luminescence emitted by the light-emitting layer 130 is short. The time it takes for the intensity of the signal to decay to 1% or less is preferably 10 ns or more and 37 μs or less, more preferably The maximum is 10 ns or more and 30 μs or less.

[0101] <Light-emitting mechanism of light-emitting elements 2> Next, an example of a configuration different from that of the light-emitting layer shown in FIG. 2(A) will be explained below with reference to FIG. 3(A). Make it clear.

[0102] FIG. 3(A) is a cross-sectional view showing an example of the light-emitting layer 130 shown in FIG. The light-emitting layer 130 shown includes a guest material 131, a host material 132, a host material 133, and It has.

[0103] In the light-emitting layer 130, the host material 132 or the host material 133 is present in the largest amount by weight. The guest material 131 is dispersed in the host material 132 and the host material 133 . Here, the guest material 131 is preferably a phosphorescent compound. and the host material 132 are preferably a combination that forms an exciplex 136 .

[0104] In addition, a combination of a guest material 131 and a host material 132 that efficiently forms an exciplex 136 is In addition, the HOMO level of one of the guest material 131 and the host material 132 is generated. The HOMO level of the material in the light-emitting layer 130 is the highest, and the LUMO level of the material in the light-emitting layer 130 is the highest. It is preferable that the guest material 13 has the lowest LUMO level among the materials in 30. The HOMO level of one of the 1 and the host material 132 is higher than the HOMO level of the other and the host material The HOMO level of the material 133 is higher than the LUMO level of the other material. It is preferable that the LUMO level of the insulating material 133 is lower than the LUMO level.

[0105] For example, the guest material 131 has a hole transporting property and the host material 132 has an electron transporting property. In this case, the HOMO level of the guest material 131 is at the same level as shown in the energy band diagram in FIG. 3(B). The level is equal to or higher than the HOMO level of the host material 132 and the HOMO level of the host material 133. Preferably, the LUMO level of the host material 132 is the same as the LUMO level of the guest material 131 and It is preferable that the LUMO level of the host material 133 is lower than the LUMO level of the host material 133. The LUMO level may be higher or lower than the LUMO level of the guest material 131 .

[0106] In addition, a combination of the host material 132 and the host material 133 that forms an exciplex 138 The combination of the host material 132 and the host material 133 is preferably Any combination that can form a hole transporting layer is acceptable, but one of the layers must have the function of transporting holes (hole transport The other is a compound that has the function of transporting electrons (electron transport property). That is, for example, it is more preferable that the host material 132 is a compound having an electron transporting property. In the case of a compound, the guest material 131 and the host material 133 are compounds having hole transport properties. When the host material 132 is a compound having a hole transporting property, the guest material The compound 131 and the host material 133 are preferably compounds having electron transport properties. The combination of the hole transporting material 132 and the host material 133 is a compound having hole transporting properties and a compound having electron transporting properties. When a compound with a carrier property is used in combination, the carrier balance can be adjusted by changing the mixing ratio. Specifically, a compound having hole transport properties: an electron transport property The compound having the above structure is preferably in the range of 1:9 to 9:1 (weight ratio). This allows for easy control of the carrier balance, and the carrier recombination region The control can also be easily performed.

[0107] In addition, a combination of the host material 132 and the host material 133 efficiently forms the exciplex 138. In addition, the HOMO level of one of the host materials 132 and 133 is higher than that of the other. Preferably, the HOMO level of one of the two is higher than or equal to the LUMO level of the other. I wish.

[0108] For example, when the host material 133 has a hole transporting property, the energy balance shown in FIG. As shown in the diagram, the HOMO level of the host material 133 is higher than that of the host material 132. the LUMO level of the host material 133 is higher than or equal to the LUMO level of the host material 132; Specifically, it is preferable that the HOMO level of the host material 132 and the HO The energy difference from the MO level is preferably 0.1 eV or more, more preferably 0.2 The L of the host material 132 is preferably 0.3 eV or more, and more preferably 0.3 eV or more. The energy difference between the UMO level and the LUMO level of the host material 133 is preferably 0.1 e V or more, more preferably 0.2 eV or more, and even more preferably 0.3 eV or more At this time, the HOMO level of the host material 133 is equal to the HOMO level of the guest material 131. It is preferable that the guest material 131 and the host material 132 form an exciplex 136. and forming an exciplex 138 with the host material 132 and the host material 133. The energy difference between the HOMO level of the guest material 131 and the HOMO level of the host material 133 is The difference is preferably 0 eV or more and 0.3 eV or less, more preferably 0 eV or more and 0.2 eV or less. The electron transport energy is preferably 0 eV or more and 0.1 eV or less.

[0109] In FIG. 3(B), Guest(131) represents the guest material 131, and Hos t(132) represents the host material 132, and Host(133) represents the host material 133. The exciplex (136) is an exciplex formed between the guest material 131 and the host material 132. Complex 136 represents the complex, and Exciplex (138) represents the complex between host material 132 and host material 133. represents the exciplex 138 formed by G The LUMO level of the guest material 131 and the HOM represents the energy difference with the O level, ΔE H1 is the LUMO level and HOMO level of the host material 132. represents the energy difference between the levels, and ΔE H2 The LUMO and HOMO levels of the host material 133 are represents the energy difference between the two positions, and ΔE Ex1 is the LUMO level of the host material 132 and the guest material represents the energy difference from the HOMO level of 131, and ΔE Ex2 is the LUM of the host material 132 is the notation and symbol that represents the energy difference between the O level and the HOMO level of the host material 133. .

[0110] At this time, the guest material 131 and the host material 132 form an exciplex 136. The excitation energy is the LUMO level of the host material 132 and the HOMO level of the guest material 131. The energy difference (ΔE Ex1 ) roughly corresponds to the LUMO level of the host material 133 and HO The energy difference between the MO level (ΔE H2 ) is preferably smaller than

[0111] The exciplex 138 formed by the host material 132 and the host material 133 is The material 132 has a LUMO molecular orbital, and the host material 133 has a HOMO molecular orbital. The excitation energy of the exciplex 138 is the same as that of the LUM of the host material 132. The energy difference (ΔE Ex2 ) roughly equivalent to , the energy difference between the LUMO level and the HOMO level of the guest material 131 (ΔE G ),host The energy difference between the LUMO level and the HOMO level of material 132 (ΔE H1 ), and the host material The energy difference (ΔE) between the LUMO level and the HOMO level of the material 133 H2 ) becomes smaller.

[0112] Therefore, the guest material 131 and the host material 132 form an exciplex 136, and the host The exciplex 138 is formed between the host material 133 and the substrate material 132, resulting in a lower excited energy. It is possible to form an excited state with a higher excitation energy. Therefore, exciplex 136 and exciplex 138 can form stable excited states. .

[0113] The light-emitting layer 130 shown in FIG. 3(A) includes a guest material 131, a host material 132, and a host material 133. The correlation between the energy levels of the SiO2 and the SiO2 material 133 is shown in FIG. The notations and symbols are as follows: Guest (131): Guest material 131 (phosphorescent compound) Host (132): Host material 132 Host (133): Host material 133 ·S G : S1 level of guest material 131 T G : T1 level of guest material 131 ·S H1 : S1 level of the host material 132 T H1 : T1 level of the host material 132 ·S H2 : S1 level of the host material 133 T H2 : T1 level of the host material 133 ·S E1 : S1 level of exciplex 136 T E1 :T1 level of exciplex 136 ·S E2 : S1 level of exciplex 138 T E2 :T1 level of exciplex 138

[0114] In the light-emitting element of one embodiment of the present invention, the guest material 131 and the host material 132 contained in the light-emitting layer 130 The host material 132 and the host material 133 form an exciplex 136 , and the host material 132 and the host material 133 form an exciplex 136 . The exciplex 136 forms an exciplex 138. The S1 level (S E1 ) and T1 of exciplex 136 Level (T E1 ) are adjacent energy levels (see route E1 in Figure 3(C)). In addition, the S1 level (S E2 ) and the T1 level of exciplex 138 (T E2 ) are adjacent energy levels (see route E3 in Figure 3(C)). The S1 level (S E1 ) and T1 level (T E1 ) is the energy difference between Preferably, it is greater than 0 eV and not greater than 0.2 eV, more preferably greater than 0 eV and not greater than 0.1 eV V or less, and the S1 level of exciplex 138 (S E2 ) and T1 level (T E2 ) and energy The difference is preferably greater than 0 eV and less than 0.2 eV, more preferably greater than 0 eV and less than 0.2 eV. It is less than 0.1 eV.

[0115] Excitation energy levels of exciplex 136 (S E1 and T E1 ) forms the exciplex 136 The S1 level (S G and S H 1), and the excited energy level of exciplex 138 (S E2 and T E2 ) is encouraging The S1 levels of each material (host material 132 and host material 133) that forms the complex 138 (S H1 and S H2 ) and therefore forms an excited state at a lower excitation energy. This makes it possible to reduce the driving voltage of the light emitting element 150. .

[0116] Then, both the singlet and triplet excitation energies of exciplex 136 are excited by The S1 level (S E1 ) and T1 level (T E1 ) to guest material 131 (phosphorescent T1 level (T G ) and the singlet excitation energy of exciplex 138. The doublet excitation energy is then transferred to the S1 level (S E2 ) and T1 level (T E 2) to the T1 level (T G ) to Light is emitted from the photoresist material 131 (see Route E2 and Route E4 in FIG. 3(C)).

[0117] The T1 level (T H1 ) and the T1 level of the host material 133 (T H2 ) is the T1 level (T E 2) or more. The T1 level (T E2 ) is the T1 level (T G ) or more In this way, the exciplex formed between the host material 132 and the host material 133 is preferably The excitation energy of the compound 138 is quenched by the host material 132 and the host material 133. This allows for efficient transfer of excitation energy from the exciplex 138 to the guest material 131. Furthermore, the excitation energy of the guest material 131 is quenched. Therefore, it becomes possible to efficiently obtain light emission from the guest material 131. In one aspect of the invention, the triplet excitation energy of exciplex 138 is There is no need for reverse intersystem crossing to the singlet excited energy level (S E2 ) The rate does not need to be high, allowing for a wide range of materials to be selected.

[0118] In addition, when the direct recombination process of carriers becomes dominant in the guest material 131, A process of forming an exciplex 136 between the material 131 and the host material 132, and a process of forming an exciplex 136 between the material 131 and the host material 13 The process of forming an exciplex 138 between the light-emitting element 2 and the host material 133 becomes difficult to occur. Therefore, the driving voltage of the exciplex 136 and the exciplex 138 are increased. The guest material 1 is transferred via the energy transfer process (Routes E1 to E4 in FIG. 3(C)). It is preferable that the host material 132 and the host 31 emit light. The weight ratio of the total amount of the host material 133 to the guest material 131 is such that the weight ratio of the guest material 131 is low. It is preferable that the host material 132 and the host material 133 are The weight ratio of the resin material 131 is preferably 0.01 or more and 0.5 or less, and more preferably 0.01 or more and 0.5 or less. Between .05 and 0.3.

[0119] The guest material 131 has an electron transporting property, and the host material 132 has a hole transporting property. In this case, as shown in the energy band diagram of FIG. The HOMO level of the material 132 is the same as the HOMO level of the guest material 131 and the HOMO level of the host material 133. The LUMO level of the guest material 131 is preferably equal to or higher than the HOMO level of the host material 13 2 and the LUMO level of the host material 133 or lower. In this case, the HOMO level of the host material 133 may be higher than the HOMO level of the guest material 131. It can be low.

[0120] The HOMO level of the host material 133 is lower than the HOMO level of the host material 132. Preferably, the LUMO level of the host material 133 is lower than the LUMO level of the host material 132. Specifically, the HOMO level of the host material 132 and the HOMO level of the host material 133 The energy difference between The LUMO level of the host material 132 is preferably 0.3 eV or more. The energy difference between the LUMO level of the host material 133 and the LUMO level of the host material 133 is preferably 0.1 eV or more. It is more preferably 0.2 eV or more, and even more preferably 0.3 eV or more. At this time, the LUMO level of the host material 133 is higher than the LUMO level of the guest material 131. Preferably, the guest material 131 and the host material 132 form an exciplex 136, In order to form an exciplex 138 between the host material 132 and the host material 133, The energy difference between the LUMO level of the resist material 131 and the LUMO level of the host material 133 is Preferably, the value is 0 eV or more and 0.3 eV or less, more preferably, 0 eV or more and 0.2 eV or less, and even more preferably, The more preferable value is 0 eV or more and 0.1 eV or less.

[0121] In addition, in Fig. 3(B)(C), the symbols having the same functions as those shown in Fig. 2(B)(C) In some cases, detailed explanations may be omitted. In such cases, please refer to the previous explanation. That's fine.

[0122] <Material> Next, components of a light-emitting element according to one embodiment of the present invention will be described in detail below.

[0123] <Light-emitting layer> The materials that can be used for the light-emitting layer 130 are described below.

[0124] The host material 132 may be any material that can form an exciplex with the guest material 131. For example, although not particularly limited, one of the host material 132 and the guest material 131 may be an electron transporting material. It is preferred that one of the two has a function of transporting electrons and the other has a function of transporting holes.

[0125] When the host material 132 has a hole transporting function, the host material 132 has an excess of π electrons. It is preferred that the compound has at least one of a heteroaromatic skeleton and an aromatic amine skeleton.

[0126] The π-electron-rich heteroaromatic skeleton of the host material 132 may be a furan skeleton, a thiophene skeleton, or a cyclohexane skeleton. Since the phenyl skeleton and the pyrrole skeleton are stable and reliable, it is preferable to select from these skeletons. It is preferable that the furan skeleton has one or more of the above. As the thiophene skeleton, a dibenzothiophene skeleton is preferred. The pyrrole skeleton includes an indole skeleton, a carbazole skeleton, and a 3-(9-phenyl -9H-carbazole-3-yl)-9H-carbazole skeleton is preferred. The skeleton may have a substituent.

[0127] The aromatic amine skeleton of the host material 132 does not have an N-H bond. A tertiary amine is preferred, and a triarylamine skeleton is particularly preferred. The aryl group of the alkylene skeleton is a substituted or unsubstituted aryl group having 6 to 13 carbon atoms forming a ring. Preferred are aryl groups, such as phenyl, naphthyl, fluorenyl, and phenanthrenyl. Examples thereof include a phenyl group and a triphenylenyl group.

[0128] The structures having π-electron-rich heteroaromatic skeletons and aromatic amine skeletons have excellent hole transport properties. It is particularly preferred because it is stable and has good reliability. For example, Examples of such structures include those having a methylamine skeleton.

[0129] Examples of the π-electron-rich heteroaromatic skeleton and aromatic amine skeleton include the following: Examples of the skeletons are those represented by the general formulae (101) to (117). X in (117) represents an oxygen atom or a sulfur atom.

[0130] [ka]

[0131] Alternatively, when the host material 132 has an electron transporting function, the host material 132 is π It is preferable that the compound has an electron-deficient heteroaromatic skeleton. Examples of the π-electron-deficient heteroaromatic skeleton include: Pyridine skeleton, diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton), and A triazine skeleton is preferred, and among them, a diazine skeleton or a triazine skeleton is stable and reliable. It is preferable because it is good.

[0132] Examples of the π-electron deficient heteroaromatic skeleton include those represented by the following general formulas (201) to (2 18). In addition, X in the general formulae (209) to (211) is Represents an oxygen atom or a sulfur atom.

[0133] [ka]

[0134] In addition, a skeleton having hole transport properties (specifically, a π-electron-rich heteroaromatic skeleton and an aromatic amine skeleton) and a skeleton having electron transport properties (specifically, a π-electron deficient complex A compound in which the aromatic skeleton is bonded directly or via an arylene group may also be used. Examples of the arylene group include a phenylene group, a biphenyldiyl group, and a naphthyl group. Examples thereof include a diyl group and a fluorenediyl group.

[0135] As a linking group that links the skeleton having hole transport properties and the skeleton having electron transport properties, Examples of the skeleton include those represented by the following general formulas (301) to (315).

[0136] [ka]

[0137] The aromatic amine skeleton (specifically, for example, a triarylamine skeleton), π-electron excess heteroaromatic skeleton (specifically, for example, a furan skeleton, a thiophene skeleton, a pyrrole skeleton) a π-electron-deficient heteroaromatic skeleton (specifically, for example, a diazine skeleton or a triazine skeleton) a ring having a skeleton), or the above general formulas (101) to (115), general formula (201) The general formulae (218) and (301) to (315) may have a substituent. The substituents include alkyl groups having 1 to 6 carbon atoms, cycloalkyl groups having 3 to 6 carbon atoms, and alkyl groups having 1 to 6 carbon atoms. alkyl groups, or substituted or unsubstituted aryl groups having 6 to 12 carbon atoms; Specific examples of alkyl groups having 1 to 6 carbon atoms include: , for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group , tert-butyl group, n-hexyl group, etc. Specific examples of the cycloalkyl group having 6 carbon atoms include a cyclopropyl group, a cyclopropyl group, and a cyclopropyl group. butyl group, cyclopentyl group, cyclohexyl group, etc. Examples of the aryl group having 6 to 12 carbon atoms include a substituted or unsubstituted phenyl group, a naphthalene group, and a phenyl group. Specific examples include a butyl group and a biphenyl group. In this case, for example, in the fluorene skeleton, When the carbon atom at position 9 in the In some cases, a spirofluorene skeleton is formed by the addition of Substitution is advantageous in terms of ease of synthesis and cost of raw materials.

[0138] In addition, Ar represents a single bond or an arylene group having 6 to 13 carbon atoms, The olefin group may have substituents, and the substituents may be bonded to each other to form a ring. An example of such a compound is a compound in which the carbon atom at the 9th position of the fluorenyl group has a phenyl group as a substituent. The two phenyl groups bond together to form a spirofluorene skeleton. Examples of the arylene group having 6 to 13 carbon atoms include: Phenylene group, naphthalenediyl group, biphenyldiyl group, fluorenediyl group, etc. In addition, when the arylene group has a substituent, the substituent Examples of the group include an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and A substituted aryl group or an aryl group having 6 to 12 carbon atoms can also be selected. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group and an ethyl group. , propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, n-butyl group and cycloalkyl groups having 3 to 6 carbon atoms. Specific examples of the alkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl ... and cyclohexyl groups. Also, aryl groups having 6 to 12 carbon atoms are examples. Specific examples of the alkyl group include a phenyl group, a naphthyl group, and a biphenyl group. This can be done.

[0139] The arylene group represented by Ar is, for example, the following structural formula (Ar-1) to (Ar- 18) can be applied. The groups that can be used as Ar are This is not limited to these.

[0140] [ka]

[0141] Also, R 1 and R 2 are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or a substituted or unsubstituted cycloalkyl group having 6 to 13 carbon atoms; represents an unsubstituted aryl group. Examples of alkyl groups having 1 to 6 carbon atoms include Specifically, for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isopropyl ... butyl group, tert-butyl group, n-hexyl group, etc. Specific examples of the cycloalkyl group having 3 to 6 carbon atoms include a cyclopropyl group. Examples include a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group. Examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, a naphthyl group, Specific examples include a biphenyl group and a fluorenyl group. The aryl group and phenyl group may have a substituent, and the substituents may be bonded to each other to form a ring. The substituent may be an alkyl group having 1 to 6 carbon atoms, a group having 3 or more carbon atoms, or a group having 4 to 6 carbon atoms. Cycloalkyl groups having up to 6 carbon atoms or aryl groups having 6 to 12 carbon atoms are also substituents. Specific examples of alkyl groups having 1 to 6 carbon atoms include: For example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t Examples of the alkyl group include an n-butyl group and an n-hexyl group. Specific examples of the cycloalkyl group having six carbon atoms include a cyclopropyl group and a cyclobutyl group. Examples of the cyclohexyl group include cyclopentyl groups, cyclohexyl groups, and cyclopentyl groups. Examples of the aryl group having up to 12 carbon atoms include a phenyl group, a naphthyl group, and a biphenyl group. Examples of specific examples include:

[0142] Also, R 1 and R 2 The alkyl group or aryl group represented by the following structural formula ( Groups represented by R-1) to (R-29) can be used. The groups that can be used as the aryl group are not limited to these.

[0143] [ka]

[0144] In addition, general formulas (101) to (117), general formulas (201) to (218), and general formula ( 301) to (315), and Ar, R 1 and R 2 The substituents that may be substituted include, for example, For example, the alkyl group or aryl group represented by the above structural formulas (R-1) to (R-24) may be suitably used. The alkyl group or aryl group can be selected from the group consisting of: This is not limited to these.

[0145] As the host material 132, for example, the following hole transporting material and electron transporting material are used: It is possible.

[0146] As the hole transporting material, a material having a higher hole transporting property than an electron transporting property can be used. x10 -6 cm 2 It is preferable that the material has a hole mobility of 1 / Vs or more. Aromatic amines, carbazole derivatives, etc. can be used as the hole transporting material. The material may be a polymer compound.

[0147] As a material having high hole transporting properties, for example, aromatic amine compounds such as N,N' -Di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviation: DTDP PA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino ]biphenyl (abbreviation: DPAB), N,N'-bis{4-[bis(3-methylphenyl) amino]phenyl}-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-di Amine (abbreviation: DNTPD), 1,3,5-tris[N-(4-diphenylaminophenyl [N-phenylamino]benzene (abbreviation: DPA3B), and the like.

[0148] Specific examples of carbazole derivatives include 3-[N-(4-diphenylamino phenyl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzDPA1 ), 3,6-bis[N-(4-diphenylaminophenyl)-N-phenylamino]-9 -phenylcarbazole (abbreviation: PCzDPA2), 3,6-bis[N-(4-diphenyl [N-(1-naphthyl)amino]-9-phenylcarbazole (abbreviation :PCzTPN2), 3-[N-(9-phenylcarbazol-3-yl)-N-phenyl 3,6-bis[N- (9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazol PCzPCA2, 3-[N-(1-naphthyl)-N-(9-phenylcarbazone] [carbazol-3-yl]amino]-9-phenylcarbazole (abbreviation: PCzPCN1) The following can be mentioned:

[0149] Other carbazole derivatives include 4,4'-di(N-carbazolyl)biphene. Nyl (abbreviation: CBP), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzoyl Zene (abbreviation: TCPB), 1,4-bis[4-(N-carbazolyl)phenyl]-2,3 , 5,6-tetraphenylbenzene, etc. can be used.

[0150] Furthermore, examples of materials with high hole transport properties include 4,4'-bis[N-(1-naphthyl )-N-phenylamino]biphenyl (abbreviation: NPB or α-NPD) and N,N'-biphenyl (3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4 '-diamine (abbreviation: TPD), 4,4',4''-tris(carbazol-9-yl) Triphenylamine (abbreviation: TCTA), 4,4',4''-tris[N-(1-naphthyl) 1'-TNATA, 4,4'-N-phenylamino]triphenylamine ,4''-Tris(N,N-diphenylamino)triphenylamine (abbreviation: TDATA ), 4,4',4''-tris[N-(3-methylphenyl)-N-phenylamino] Triphenylamine (abbreviation: m-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)triflate Phenylamine (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}phenyl DFLADFL, N-(9,9-dimethyl-2-diphenylamino-9H -fluoren-7-yl)diphenylamine (abbreviation: DPNF), 2-[N-(4-diphenyl)- (phenylaminophenyl)-N-phenylamino]spiro-9,9'-bifluorene (abbreviation :DPASF), 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl ) triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9 -phenyl-9H-carbazol-3-yl)triphenylamine (abbreviated as PCBBi1 BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl ) Triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4'' -(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCB NBB), 4-phenyldiphenyl-(9-phenyl-9H-carbazol-3-yl) Amine (abbreviation: PCA1BP), N,N'-bis(9-phenylcarbazol-3-yl) )-N,N'-diphenylbenzene-1,3-diamine (abbreviation: PCA2B), N,N' ,N''-triphenyl-N,N',N''-tris(9-phenylcarbazole-3- N-(4-biphenylyl)benzene-1,3,5-triamine (abbreviation: PCA3B), )-N-(9,9-dimethyl-9H-fluoren-2-yl)-9-phenyl-9H-carboxylate PCBiF, N-(1,1'-biphenyl-4-yl) )-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9- Dimethyl-9H-fluoren-2-amine (abbreviation: PCBBiF), 9,9-dimethyl- N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl] Fluorene-2-amine (abbreviation: PCBAF), N-phenyl-N-[4-(9-phenyl (9H-carbazol-3-yl)phenyl]spiro-9,9'-bifluorene-2- Amine (abbreviation: PCBASF), 2-[N-(9-phenylcarbazol-3-yl)- N-phenylamino]spiro-9,9'-bifluorene (abbreviation: PCASF), 2,7- Bis[N-(4-diphenylaminophenyl)-N-phenylamino]-spiro-9,9 '-bifluorene (abbreviation: DPA2SF), N-[4-(9H-carbazol-9-yl )phenyl]-N-(4-phenyl)phenylaniline (abbreviation: YGA1BP), N,N '-Bis[4-(carbazol-9-yl)phenyl]-N,N'-diphenyl-9,9 -Dimethylfluorene-2,7-diamine (abbreviation: YGA2F) and other aromatic amine compounds Also, 3-[4-(1-naphthyl)-phenyl]-9-phenyl can be used. 9H-carbazole (abbreviation: PCPN), 3-[4-(9-phenanthryl)- phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPPn), 3,3'-bis( 9-phenyl-9H-carbazole) (abbreviation: PCCP), 1,3-bis(N-carbazole) mCP, 3,6-bis(3,5-diphenylphenyl)-9- Phenylcarbazole (abbreviation: CzTP), 4-{3-[3-(9-phenyl-9H-phenyl) (mmDBFFLBi -II), 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) DBF3P-II), 1,3,5-tri(dibenzothiophen-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-fluoren-9-yl)phenyl]-6 -phenyldibenzothiophene (abbreviation: DBTFLP-IV), 4-[3-(triphenyl (2-phenyl)dibenzothiophene (abbreviation: mDBTPTp-II) Mine compounds, carbazole compounds, thiophene compounds, furan compounds, fluorene compounds , triphenylene compounds, phenanthrene compounds, etc. can be used. The substance is mainly 1×10 -6 cm 2 A material with a hole mobility of 1 / Vs or more. Any other substance may be used as long as it has a higher hole transporting property than electron transporting property.

[0151] As the electron transporting material, a material having a higher electron transporting property than a hole transporting property can be used. x10 -6 cm 2 It is preferable that the material has an electron mobility of 1 / Vs or more. Materials that are easy to absorb (materials with electron transport properties) include gold containing zinc or aluminum. using π-electron-deficient heteroaromatic compounds such as metal complexes and nitrogen-containing heteroaromatic compounds. The metal complexes include quinoline ligands, benzoquinoline ligands, oxazoline ligands, and the like. Metal complexes having thiazole or thiazole ligands are also known. Heteroaromatic compounds include oxadiazole derivatives, triazole derivatives, phenanthrene derivatives, and the like. Loline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, triazine derivatives Examples include the body.

[0152] For example, tris(8-quinolinolato)aluminum(III) (abbreviation: Alq), tri Bis(4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Almq3), Bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation: BeBq2 ), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum ( III) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Znq) These include metal complexes having a quinoline skeleton or a benzoquinoline skeleton. Bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO) , bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ) Metal complexes having oxazole or thiazole ligands such as In addition to metal complexes, 2-(4-biphenylyl)-5-(4-tert-butyl phenyl)-1,3,4-oxadiazole (abbreviation: PBD) and 1,3-bis[5-( p-tert-butylphenyl)-1,3,4-oxadiazol-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), 2,2',2''-(1,3,5-benzenetriyl)tris(1- phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophene [(4-phenyl-phenyl)-1-phenyl-1H-benzimidazole (abbreviation: mD BTBIm-II), bathophenanthroline (abbreviated as BPhen), bathocuproine ( Abbreviation: BCP), 2,9-bis(naphthalen-2-yl)-4,7-diphenyl-1,1 Heterocyclic compounds such as 0-phenanthroline (abbreviated as NBPhen) and 2-[3-(dibenzyl) (benzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mD BTPDBq-II), 2-[3'-(dibenzothiophen-4-yl)biphenyl-3 -yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2- [3'-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h] Quinoxaline (abbreviation: 2mCzBPDBq), 2-[4-(3,6-diphenyl-9H- (carbazol-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzP DBq-III), 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[ f,h]quinoxaline (abbreviation: 7mDBTPDBq-II) and 6-[3-(dibenzyl 6mDB TPDBq-II), 4,6-bis[3-(phenanthrene-9-yl)phenyl]pyridine 4,6mPnP2Pm, 4,6-bis[3-(4-dibenzothienyl) phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis[3-( 9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm) Heterocyclic compounds with diazine skeletons such as 2-{4-[3-(N-phenyl-9H- (carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl Phenyl-1,3,5-triazine (abbreviation: PCCzPTzn) and other compounds with a triazine skeleton Heterocyclic compounds such as 3,5-bis[3-(9H-carbazol-9-yl)phenyl] Pyridine (abbreviation: 35DCzPPy), 1,3,5-tri[3-(3-pyridyl)phenyl] Heterocyclic compounds with a pyridine skeleton, such as 4,4 '-Bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOs) Any heteroaromatic compound can be used. Also, poly(2,5-pyridinediyl) ( Abbreviation: PPy), poly[(9,9-dihexylfluorene-2,7-diyl)-co-( pyridine-3,5-diyl)] (abbreviation: PF-Py), poly[(9,9-dioctylfluor) oren-2,7-diyl)-co-(2,2'-bipyridine-6,6'-diyl)](abbreviation Polymer compounds such as PF-BPy can also be used. Mainly 1×10 -6 cm 2 / Vs or more. Any substance other than those mentioned above may be used as long as it has a high electron transporting property.

[0153] <Specific examples of bipyridine derivatives> The bipyridine derivatives include compounds represented by the following structural formulas (500) to (502). The compounds represented by the following structural formulas (500) to (502) are compounds of the present invention. It can be suitably used as the host material 132 used in one embodiment of the light-emitting element. The bipyridine derivatives are not limited to the following examples.

[0154] [ka]

[0155] The guest material 131 preferably has a function of converting triplet excitation energy into luminescence. When the guest material 131 has a heavy metal, the spin-orbit interaction (the spin angle of the electron) Intersystem crossing between the singlet and triplet states is promoted by the interaction of the orbital momentum and the orbital angular momentum. Since the guest material 131 undergoes a transition between the singlet ground state and the triplet excited state, That is, the transition between the singlet ground state and the triplet excited state of the guest material 131 is allowed. The efficiency of the emission and the probability of absorption related to the transition can be increased. The material 131 preferably contains a metal element with a large spin-orbit interaction, and in particular, a platinum group element. (Ruthenium (Ru), Rhodium (Rh), Palladium (Pd), Osmium (Os), It is preferable to have iridium (Ir) or platinum (Pt), and among these, iridium By having This can be increased, which is preferable.

[0156] The guest material 131 (phosphorescent compound) may be iridium, rhodium, or white. Examples include gold-based organometallic complexes and metal complexes. Among them, organic iridium complexes, such as iridium complexes, The orthometalated ammonium complex is preferred. The orthometalated ligand is 4H-triazolium. 1H-triazole ligands, 1H-triazole ligands, imidazole ligands, pyridine ligands, pyrimidine ligands Examples of the ligand include an azine ligand, a pyrazine ligand, and an isoquinoline ligand. , guest material 131 (phosphorescent compound) is triplet MLCT (Metal to Ligan). d Charge Transfer (Cat 1, 2, 3) transition absorption band.

[0157] The guest material 131 (phosphorescent compound) is a compound that forms an exciplex with the host material 132. This provides a high luminous efficiency and allows driving at a low voltage. A light emitting element can be provided.

[0158] Examples of substances having a blue or green emission peak include tris{2-[5-(2 -methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazo 3-yl-κN 2 ]phenyl-κC}iridium(III) (abbreviation: Ir(mpp tz-dmp)3), tris(5-methyl-3,4-diphenyl-4H-1,2,4-trimethyl- Triazolato)iridium(III) (abbreviation: Ir(Mptz)3), tris[4-(3- Biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazolato]i Iridium(III) (abbreviation: Ir(iPrptz-3b)3), tris[3-(5-biphenyl] (phenyl)-5-isopropyl-4-phenyl-4H-1,2,4-triazolato]irid Ir(III) (abbreviated as Ir(iPr5btz)3), a 4H-triazole skeleton and organometallic iridium complexes with tris[3-methyl-1-(2-methylphenyl) -5-phenyl-1H-1,2,4-triazolato]iridium(III) (abbreviation: Ir (Mptz1-mp)3), tris(1-methyl-5-phenyl-3-propyl-1H- 1,2,4-Triazolate)iridium(III) (abbreviation: Ir(Prtz1-Me) 3) and fac-triazole-based organometallic iridium complexes. S[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]isopropyl Iridium(III) (abbreviation: Ir(iPrpmi)3), tris[3-(2,6-dimethyl phenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(I II) Imidazole skeleton-containing compounds such as Ir(dmpimpt-Me) Organic metal iridium complexes and bis[2-(4',6'-difluorophenyl)pyridinato- N,C 2’ ]iridium(III) tetrakis(1-pyrazolyl)borate (abbreviation: FI r6), bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2’ ]Ili Dium(III) picolinate (abbreviation: FIrpic), bis{2-[3',5'-bis (Trifluoromethyl)phenyl]pyridinato-N,C 2’}Iridium(III) pico Ir(CF3ppy)2(pic) (fluorophenyl)pyridinato-N,C 2’ ]Iridium(III) acetylacetonate (abbreviation: FIr(acac)) Among the above, 4H-triazole is an organometallic iridium complex. a nitrogen-containing five-membered heterocyclic skeleton such as a 1H-triazole skeleton and an imidazole skeleton; The organometallic iridium complexes have high triplet excitation energy and are highly reliable and highly efficient. It is particularly preferred because it is also excellent in

[0159] Furthermore, examples of substances having a green or yellow emission peak include tris(4-methylphenyl) Ir(mppm)3, Tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: I r(tBuppm)3), (acetylacetonato)bis(6-methyl-4-phenylpyridine) Iridium(III) (abbreviation: Ir(mppm)2(acac)), (acetylacetonate ruacetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium( III) (Abbreviation: Ir(tBuppm)2(acac)), (acetylacetonato)bis [4-(2-norbornyl)-6-phenylpyrimidinato]iridium(III) (abbreviation : Ir(nbppm)2(acac)), (acetylacetonato)bis[5-methyl-6 -(2-methylphenyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: Ir(mpmppm)2(acac)), (acetylacetonato)bis{4,6-dimethyl 2-[6-(2,6-dimethylphenyl)-4-pyrimidinyl-κN3]phenyl- κC}iridium(III) (abbreviation: Ir(dmppm-dmp)2(acac)), ( acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III)( Organometallic iridium compounds with pyrimidine skeletons, such as Ir(dppm)2(acac) complexes and (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazine Iridium(III) (abbreviation: Ir(mppr-Me)2(acac)), (acetyl arylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazinato)iridide Pyrazine skeletons such as Ir(III) (abbreviation: Ir(mppr-iPr)2(acac)) Organometallic iridium complexes and tris(2-phenylpyridinato-N,C 2’ ) Iridium(III) (abbreviation: Ir(ppy)3), bis(2-phenylpyridinato-N ,C 2’ ) Iridium(III) acetylacetonate (abbreviation: Ir(ppy)2(ac ac)), bis(benzo[h]quinolinato)iridium(III) acetylacetonate (abbreviation: Ir(bzq)2(acac)), tris(benzo[h]quinolinato)iridium Ir(III) (abbreviation: Ir(bzq)3), tris(2-phenylquinolinato-N,C 2 ’ ) Iridium(III) (abbreviation: Ir(pq)3), bis(2-phenylquinolinato- N,C 2’ ) Iridium(III) acetylacetonate (abbreviation: Ir(pq)2(ac Organometallic iridium complexes with pyridine skeletons such as bis(2,4-difluoromethyl) Phenyl-1,3-oxazolato-N,C 2’ ) Iridium(III) acetylacetoner Ir(dpo)2(acac)), bis{2-[4'-(perfluorophenyl) (phenyl)pyridinato-N,C 2’}Iridium(III) acetylacetonate( Abbreviation: Ir(p-PF-ph)2(acac)), bis(2-phenylbenzothiazol- -N,C 2’ ) Iridium(III) acetylacetonate (abbreviation: Ir(bt)2(a In addition to organometallic iridium complexes such as tris(acetylacetonato)(monophenyl) Anthroline) terbium(III) (abbreviation: Tb(acac)3(Phen)) Among the above, organometallic iridium complexes having a pyrimidine skeleton are Dium complexes are particularly preferred because they are remarkably excellent in reliability and luminous efficiency.

[0160] Furthermore, examples of substances having a yellow or red emission peak include (diisobutyryl) Methanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(II I) (abbreviation: Ir(5mdppm)2(dibm)), bis[4,6-bis(3-methyl [phenyl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: Ir (5mdppm)2(dpm)), bis[4,6-di(naphthalen-1-yl)pyrimidinyl] Nato](dipivaloylmethanato)iridium(III) (abbreviation: Ir(d1npm)2( Organometallic iridium complexes with pyrimidine skeletons, such as (acetylacetonyl acetone) Iridium(III) (abbreviation: I r(tppr)2(acac)), bis(2,3,5-triphenylpyrazinate)(dipyr Valoylmethanato)iridium(III) (abbreviation: Ir(tppr)2(dpm)), ( Acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]i Ir(Fdpq)2(acac) and other pyrazine-based compounds Organometallic iridium complexes and tris(1-phenylisoquinolinato-N,C 2’ ) Iridium(III) (abbreviation: Ir(piq)3), bis(1-phenylisoquinolinato) -N,C 2’ ) Iridium(III) acetylacetonate (abbreviation: Ir(piq)2( In addition to organometallic iridium complexes with pyridine skeletons such as acac), 2,3,7, 8,12,13,17,18-Octaethyl-21H,23H-porphyrin platinum(II) ) (abbreviation: PtOEP) and tris(1,3-diphenyl-1,3-propanediol). Eu(DB)(propanedionato)(monophenanthroline)europium(III) M)3(Phen)), tris[1-(2-thenoyl)-3,3,3-trifluoroacetate [Tonato](monophenanthroline)europium(III) (abbreviation: Eu(TTA)3( Among the above, rare earth metal complexes such as pyrimidine skeletons are Organometallic iridium complexes having the above structure are particularly preferred because they are remarkably excellent in reliability and luminous efficiency. In addition, organometallic iridium complexes with a pyrazine skeleton can emit red light with good chromaticity. can be done.

[0161] In addition, among the above-mentioned iridium complexes, those with a 4H-triazole skeleton and a 1H-triazole skeleton Organometallic iridium compounds with nitrogen-containing five-membered heterocyclic skeletons such as imidazole skeletons In complexes and iridium complexes with a pyridine skeleton, the electron-accepting ability of the ligands is low, and the HOMO Since the level is likely to be high, this is suitable for one embodiment of the present invention.

[0162] In addition, among the organometallic iridium complexes having a nitrogen-containing five-membered heterocyclic skeleton, at least sialic acid is preferred. Iridium complexes with substituents containing cyano groups exhibit LUM due to the strong electron-withdrawing properties of the cyano groups. Since the O level and the HOMO level are appropriately lowered, the compound is suitable for use in the light-emitting element of one embodiment of the present invention. In addition, the iridium complex has a high triplet excitation energy level. Therefore, by using the iridium complex in a light-emitting element, blue light with good luminous efficiency can be emitted. Furthermore, the iridium complex can be repeatedly oxidized and reduced, and thus a light-emitting device can be fabricated. Since the iridium complex has good resistance to light, it can be used in light-emitting devices to A light-emitting element with a long life can be manufactured.

[0163] From the viewpoint of stability and reliability of device characteristics, a cyano group is added to the nitrogen-containing five-membered heterocyclic skeleton. Preferably, the iridium complex has a ligand to which an aryl group containing The number of carbon atoms in the alkyl group is preferably 6 to 13. In this case, the iridium complex is Since vacuum deposition can be performed at a relatively low temperature, deterioration such as thermal decomposition during deposition is unlikely to occur.

[0164] In addition, a cyano group is bonded to a nitrogen atom of the nitrogen-containing five-membered heterocyclic skeleton via an arylene group. Iridium complexes with linked ligands can maintain a high triplet excited energy level. Therefore, it can be suitably used for light emitting elements that emit high energy light, such as blue light. In addition, compared to those without cyano groups, they exhibit high-energy emission such as blue light. Furthermore, the introduction of a cyano group into such a specific position results in a highly efficient light-emitting device. By doing so, it is possible to obtain a highly reliable light-emitting element that emits high-energy light such as blue light. It should be noted that there is a phenanthroline bond between the nitrogen-containing five-membered heterocyclic skeleton and the cyano group. Attachment via an arylene group such as an nylene group is preferred.

[0165] When the arylene group has 6 to 13 carbon atoms, the iridium complex is Since it is a compound with a relatively low molecular weight, it is suitable for vacuum deposition (a compound that can be vacuum deposited at a relatively low temperature). Generally, when the molecular weight is low, the heat resistance after film formation is poor. The iridium complex has multiple ligands, so it has sufficient heat resistance even if the molecular weight of the ligands is low. This has the advantage of ensuring reliability.

[0166] That is, the iridium complex has the following advantages in addition to the ease of deposition and electrochemical stability described above: The triplet excitation energy level of the compound of the present invention is high. In a light-emitting element, the iridium complex is preferably used as a guest material in a light-emitting layer. Among these, it is particularly suitable for use as a guest material in a blue light-emitting device.

[0167] <Examples of iridium complexes> The iridium complex is represented by the following general formula (G1).

[0168] [ka]

[0169] In the above general formula (G1), Ar 1 and Ar 2 each independently represents a group having 6 to 1 carbon atoms; The aryl group having 6 to 13 carbon atoms is a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. Specific examples include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. When the aryl group has a substituent, the substituent may be an alkyl group having 1 to 6 carbon atoms. an alkyl group, a cycloalkyl group having 3 to 6 carbon atoms, or a substituted or unsubstituted alkyl group having 6 to 13 carbon atoms; An unsubstituted aryl group can also be selected as a substituent. Specific examples of the group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, Examples include an isobutyl group, a tert-butyl group, and an n-hexyl group. Specific examples of the cycloalkyl group having 3 to 6 carbon atoms include a cyclopropyl group, a cyclobutene group, and a cyclobutene group. Examples of the alkyl group include cyclohexyl, cyclopentyl, and cyclohexyl. The aryl group having 6 to 13 carbon atoms includes a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, and the like. Specific examples include a methyl group and a methyl group.

[0170] Also, Q 1 and Q 2 each independently represents N or CR, and R represents hydrogen, the number of carbon atoms, an alkyl group having 1 to 6 carbon atoms, a haloalkyl group having 1 to 6 carbon atoms, or a group having 6 to 13 carbon atoms; represents a substituted or unsubstituted aryl group. 1 and Q 2 At least one of the following is CR Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, and a propyl group. propyl, isopropyl, butyl, isobutyl, tert-butyl, n-hexyl In addition, examples of the haloalkyl group having 1 to 6 carbon atoms include at least At least one hydrogen atom is replaced by a group 17 element (fluorine, chlorine, bromine, iodine, astatine) Substituted alkyl groups, such as alkyl fluorides, alkyl chlorides, and alkyl bromides; Examples of the alkyl iodide include methyl fluoride, methyl chloride, and fluoride. ethyl group, ethyl chloride group, etc., but the number of halogen atoms contained or The type of each may be one or more. Specific examples of the group include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. Furthermore, the aryl group may have a substituent, and the substituent The groups may be bonded to each other to form a ring. The substituents include alkyl groups having 1 to 6 carbon atoms. A cycloalkyl group having 3 to 6 carbon atoms, or an aryl group having 6 to 13 carbon atoms may also be substituted. Specific examples of alkyl groups having 1 to 6 carbon atoms include methyl groups. propyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl Examples of the cycloalkyl group include a cycloalkyl group having 3 to 6 carbon atoms, an n-ethyl group, and an n-hexyl group. Specific examples of alkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, and cyclopentyl groups. Examples of the aryl group having 6 to 13 carbon atoms include a cyclohexyl group and the like. Specific examples of the alkyl group include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. It is possible.

[0171] Also, Ar 1 and Ar 2 and at least one of an aryl group represented by has a cyano group.

[0172] In addition, examples of iridium complexes that can be suitably used in the light-emitting element of one embodiment of the present invention include The iridium complex is preferably an orthometal complex represented by the following general formula (G2): It is an iridium complex represented by the formula:

[0173] [ka]

[0174] In the above general formula (G2), Ar 1 is a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. The aryl group having 6 to 13 carbon atoms includes a phenyl group, a naphthyl group, a biphenyl group, and a phenyl group. Specific examples of the aryl group include an aryl group and a fluorenyl group. When the substituent is present, the substituent is an alkyl group having 1 to 6 carbon atoms, an alkyl group having 3 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. Specific examples of alkyl groups having 1 to 6 carbon atoms include methyl groups. propyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl Examples of the cycloalkyl group include a cycloalkyl group having 3 to 6 carbon atoms, an n-ethyl group, and an n-hexyl group. Specific examples of alkyl groups include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, Examples of the aryl group having 6 to 13 carbon atoms include a cyclohexyl group. Specific examples of the alkyl group include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. It is possible.

[0175] Also, R 1 ~R 4 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, or Specific examples of alkyl groups having 1 to 6 carbon atoms include methyl and cyano groups. propyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl Examples of the cycloalkyl group include a cycloalkyl group having 3 to 6 carbon atoms, an n-ethyl group, and an n-hexyl group. Specific examples of alkyl groups include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, Examples of the aryl group having 6 to 13 carbon atoms include a cyclohexyl group. Specific examples of the alkyl group include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. It is possible to do this. 1 ~R 4 The fact that all of the It is advantageous in terms of price.

[0176] Also, Q 1 and Q 2 each independently represents N or CR, and R represents hydrogen, the number of carbon atoms, an alkyl group having 1 to 6 carbon atoms, a haloalkyl group having 1 to 6 carbon atoms, or a group having 6 to 13 carbon atoms; represents a substituted or unsubstituted aryl group. 1 and Q 2 At least one of the following is CR Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, and a propyl group. propyl, isopropyl, butyl, isobutyl, tert-butyl, n-hexyl In addition, examples of the haloalkyl group having 1 to 6 carbon atoms include at least At least one hydrogen atom is replaced by a group 17 element (fluorine, chlorine, bromine, iodine, astatine) Substituted alkyl groups, such as alkyl fluorides, alkyl chlorides, and alkyl bromides; Examples of the alkyl iodide include methyl fluoride, methyl chloride, and fluoride. ethyl group, ethyl chloride group, etc., but the number of halogen atoms contained or The type of each may be one or more. Specific examples of the group include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. Furthermore, the aryl group may have a substituent, and the substituent The groups may be bonded to each other to form a ring. The substituents include alkyl groups having 1 to 6 carbon atoms. A cycloalkyl group having 3 to 6 carbon atoms, or an aryl group having 6 to 13 carbon atoms may also be substituted. Specific examples of alkyl groups having 1 to 6 carbon atoms include methyl groups. propyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl Examples of the cycloalkyl group include a cycloalkyl group having 3 to 6 carbon atoms, an n-ethyl group, and an n-hexyl group. Specific examples of alkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, and cyclopentyl groups. Examples of the aryl group having 6 to 13 carbon atoms include a cyclohexyl group and the like. Specific examples of the alkyl group include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. It is possible.

[0177] Also, Ar 1 and R 1 ~R 4 an aryl group represented by R, and an aryl group represented by R 1 ~ R 4 At least one of them has a cyano group.

[0178] In addition, in an iridium complex that can be suitably used for the light-emitting element of one embodiment of the present invention, The 4H-triazole skeleton of the benzophenone-1 has a high triplet excitation energy level. This is particularly suitable for light-emitting elements that emit high-energy light such as blue light. The iridium complex is preferably represented by the following general formula (G3): It is an iridium complex.

[0179] [ka]

[0180] In the above general formula (G3), Ar 1 is a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. The aryl group having 6 to 13 carbon atoms includes a phenyl group, a naphthyl group, a biphenyl group, and a phenyl group. Specific examples of the aryl group include an aryl group and a fluorenyl group. When the substituent is present, the substituent is an alkyl group having 1 to 6 carbon atoms, an alkyl group having 3 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. Specific examples of alkyl groups having 1 to 6 carbon atoms include methyl groups. propyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl Examples of the cycloalkyl group include a cycloalkyl group having 3 to 6 carbon atoms, an n-ethyl group, and an n-hexyl group. Specific examples of alkyl groups include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, Examples of the aryl group having 6 to 13 carbon atoms include a cyclohexyl group. Specific examples of the alkyl group include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. It is possible.

[0181] Also, R 1 ~R 4 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, or Specific examples of alkyl groups having 1 to 6 carbon atoms include methyl and cyano groups. propyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl Examples of the cycloalkyl group include a cycloalkyl group having 3 to 6 carbon atoms, an n-ethyl group, and an n-hexyl group. Specific examples of alkyl groups include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, Examples of the aryl group having 6 to 13 carbon atoms include a cyclohexyl group. Specific examples of the alkyl group include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. It is possible to do this. 1 ~R 4 The fact that all of the It is advantageous in terms of price.

[0182] Also, R 5 represents hydrogen, an alkyl group having 1 to 6 carbon atoms, or a haloalkyl group having 1 to 6 carbon atoms. or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, and an isopropyl group. Examples of suitable alkyl groups include butyl, isobutyl, tert-butyl, and n-hexyl groups. The haloalkyl group having 1 to 6 carbon atoms is preferably a group having at least one hydrogen atom. Alkyl groups substituted with group 17 elements (fluorine, chlorine, bromine, iodine, astatine) alkyl fluoride, alkyl chloride, alkyl bromide, alkyl iodide Specifically, methyl fluoride group, methyl chloride group, ethyl fluoride group, ethylene chloride group, etc. The number or type of halogen atoms contained in each of these groups is The aryl group having 6 to 13 carbon atoms may be one or more. Specific examples include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. Furthermore, the aryl group may have substituents, and the substituents may be bonded to each other. The substituent may be an alkyl group having 1 to 6 carbon atoms, a group having 3 or more carbon atoms, or a group having 4 or more carbon atoms. A cycloalkyl group having from 6 to 6 carbon atoms or an aryl group having from 6 to 13 carbon atoms is also selected as a substituent. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, Propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, n-hexyl group Examples of the cycloalkyl group having 3 to 6 carbon atoms include a cycloalkyl group and a cycloalkyl group. Specifically, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, etc. Examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, Specific examples include a naphthyl group, a biphenyl group, and a fluorenyl group.

[0183] Also, Ar1 and R 1 ~R 5 and an aryl group represented by R 1 ~R 4 At least one of , having a cyano group.

[0184] In addition, in an iridium complex that can be suitably used for the light-emitting element of one embodiment of the present invention, has a high triplet excited energy level due to the imidazole skeleton as a ligand. It can be used particularly suitably for light emitting elements that emit high energy light such as blue light. The iridium complex is preferably an iridium complex represented by the following general formula (G4): It is a lithium complex.

[0185] [ka]

[0186] In the above general formula (G4), Ar 1 is a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. The aryl group having 6 to 13 carbon atoms includes a phenyl group, a naphthyl group, a biphenyl group, and a phenyl group. Specific examples of the aryl group include an aryl group and a fluorenyl group. When the substituent is present, the substituent is an alkyl group having 1 to 6 carbon atoms, an alkyl group having 3 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. Specific examples of alkyl groups having 1 to 6 carbon atoms include methyl groups. propyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl Examples of the cycloalkyl group include a cycloalkyl group having 3 to 6 carbon atoms, an n-ethyl group, and an n-hexyl group. Specific examples of alkyl groups include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, Examples of the aryl group having 6 to 13 carbon atoms include a cyclohexyl group. Specific examples of the alkyl group include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. It is possible.

[0187] Also, R 1 ~R 4 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms; Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, and a methyl group. propyl, isopropyl, butyl, isobutyl, tert-butyl, n -hexyl group, etc. Furthermore, cycloalkyl groups having 3 to 6 carbon atoms, Specific examples of the alkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cyclohexyl group. Examples of the aryl group having 6 to 13 carbon atoms include phenyl groups and the like. Specific examples include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. In addition, R 1 ~R 4 The fact that it is all hydrogen makes it easy to synthesize and the cost of raw materials. It is advantageous.

[0188] Also, R 5 and R 6 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a haloalkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms; Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, and the like. group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, n- Examples of haloalkyl groups having 1 to 6 carbon atoms include hexyl groups. At least one hydrogen atom is a group 17 element (fluorine, chlorine, bromine, iodine, astatine) alkyl groups substituted with alkyl fluorides, alkyl chlorides, alkyl bromides, Examples of alkyl groups include alkyl iodides, and alkyl iodides. Specifically, examples include methyl fluoride groups and methyl chloride groups. , ethyl fluoride group, ethyl chloride group, etc., but the halogen elements contained The number or type may be one or more. The aryl group includes a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, etc. Further, the aryl group may have a substituent, The substituents may be bonded to each other to form a ring. an alkyl group having 3 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an aryl group having 6 to 13 carbon atoms; Groups can also be selected as substituents. Specific examples of alkyl groups having 1 to 6 carbon atoms include: is a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a te Examples of the alkyl group include butyl groups and n-hexyl groups. Specific examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, and a cyclopentyl group. aryl groups, cyclohexyl groups, etc., and aryl groups having 6 to 13 carbon atoms. Specific examples of the group include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. These can be listed as follows.

[0189] Also, Ar 1 , and R 1 ~R 6 and an aryl group represented by R 1 ~R 4 At least one of has a cyano group.

[0190] In addition, in an iridium complex that can be suitably used for the light-emitting element of one embodiment of the present invention, The aryl group bonded to the nitrogen atom of the nitrogen-containing five-membered heterocyclic skeleton is a substituted or unsubstituted phenyl group. In this case, vacuum deposition can be performed at a relatively low temperature, and the triplet excitation energy level is high. In particular, it can be suitably used in a light-emitting element that emits high-energy light such as blue light. The iridium complexes are preferably iridium complexes represented by the following general formulas (G5) and (G6): It is the body.

[0191] [ka]

[0192] In the above general formula (G5), R 7 and R 11 represents an alkyl group having 1 to 6 carbon atoms; , R 7 and R 11 The alkyl groups having 1 to 6 carbon atoms are specifically Specifically, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, Examples include a tert-butyl group and an n-hexyl group.

[0193] Also, R 8 ~R 10 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, a substituted or unsubstituted phenyl group, or a cyano group; Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, Propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, n-hexyl group Examples of cycloalkyl groups having 3 to 6 carbon atoms include cycloalkyl groups such as cycloalkyl groups having 3 to 6 carbon atoms and cycloalkyl groups having 6 to 6 carbon atoms. Specifically, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group In addition, R 8 ~R 10 At least one of the groups has a cyano group. It is preferable.

[0194] Also, R 1 ~R 4 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms; Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, and a methyl group. propyl, isopropyl, butyl, isobutyl, tert-butyl, n -hexyl group, etc. Furthermore, cycloalkyl groups having 3 to 6 carbon atoms, Specific examples of the alkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cyclohexyl group. Examples of the aryl group having 6 to 13 carbon atoms include phenyl groups and the like. Specific examples include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. In addition, R 1 ~R 4 The fact that it is all hydrogen makes it easy to synthesize and the cost of raw materials. It is advantageous.

[0195] Also, R 5 represents hydrogen, an alkyl group having 1 to 6 carbon atoms, or a haloalkyl group having 1 to 6 carbon atoms. or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, and an isopropyl group. Examples of suitable alkyl groups include butyl, isobutyl, tert-butyl, and n-hexyl groups. The haloalkyl group having 1 to 6 carbon atoms is preferably a group having at least one hydrogen atom. Alkyl groups substituted with group 17 elements (fluorine, chlorine, bromine, iodine, astatine) alkyl fluoride, alkyl chloride, alkyl bromide, alkyl iodide Specifically, methyl fluoride group, methyl chloride group, ethyl fluoride group, ethylene chloride group, etc. The number or type of halogen atoms contained in each of these groups is The aryl group having 6 to 13 carbon atoms may be one or more. Specific examples include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. Furthermore, the aryl group may have substituents, and the substituents may be bonded to each other. The substituent may be an alkyl group having 1 to 6 carbon atoms, a group having 3 or more carbon atoms, or a group having 4 or more carbon atoms. A cycloalkyl group having from 6 to 6 carbon atoms or an aryl group having from 6 to 13 carbon atoms is also selected as a substituent. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, Propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, n-hexyl group Examples of the cycloalkyl group having 3 to 6 carbon atoms include a cycloalkyl group and a cycloalkyl group. Specifically, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, etc. Examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, Specific examples include a naphthyl group, a biphenyl group, and a fluorenyl group.

[0196] [ka]

[0197] In the above general formula (G6), R 7 and R11 represents an alkyl group having 1 to 6 carbon atoms; , R 7 and R 11 The alkyl groups having 1 to 6 carbon atoms are specifically Specifically, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, Examples include a tert-butyl group and an n-hexyl group.

[0198] R 8 ~R 10 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, or a group having 3 or more carbon atoms. cycloalkyl group, substituted or unsubstituted phenyl group, or cyano group Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, and a propyl group. butyl, isobutyl, tert-butyl, n-hexyl Specific examples of the cycloalkyl group having 3 to 6 carbon atoms include: Examples of the cyclopropyl group include cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl groups. In addition, R 8 ~R 10 At least one of the groups may have a cyano group. preferable.

[0199] Also, R 1 ~R 4 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms; Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, and a methyl group. propyl, isopropyl, butyl, isobutyl, tert-butyl, n -hexyl group, etc. Furthermore, cycloalkyl groups having 3 to 6 carbon atoms, Specific examples of the alkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cyclohexyl group. Examples of the aryl group having 6 to 13 carbon atoms include phenyl groups and the like. Specific examples include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. In addition, R 1 ~R 4 The fact that it is all hydrogen makes it easy to synthesize and the cost of raw materials. It is advantageous.

[0200] Also, R 5 and R 6 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a haloalkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms; Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, and the like. group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, n- Examples of haloalkyl groups having 1 to 6 carbon atoms include hexyl groups. At least one hydrogen atom is a group 17 element (fluorine, chlorine, bromine, iodine, astatine) alkyl groups substituted with alkyl fluorides, alkyl chlorides, alkyl bromides, Examples of alkyl groups include alkyl iodides, and alkyl iodides. Specifically, examples include methyl fluoride groups and methyl chloride groups. , ethyl fluoride group, ethyl chloride group, etc., but the halogen elements contained The number or type may be one or more. The aryl group includes a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, etc. Further, the aryl group may have a substituent, The substituents may be bonded to each other to form a ring. an alkyl group having 3 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an aryl group having 6 to 13 carbon atoms; Groups can also be selected as substituents. Specific examples of alkyl groups having 1 to 6 carbon atoms include: is a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a te Examples of the alkyl group include butyl groups and n-hexyl groups. Specific examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, and a cyclopentyl group. aryl groups, cyclohexyl groups, etc., and aryl groups having 6 to 13 carbon atoms. Specific examples of the group include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. These can be listed as follows.

[0201] In addition, in an iridium complex that can be suitably used for the light-emitting element of one embodiment of the present invention, The 1H-triazole skeleton of the benzophenone-1 has a high triplet excitation energy level. Since it can have a position, it is particularly suitable for light-emitting elements that emit high energy light such as blue light. The iridium complex is preferably represented by the following general formula (G7): and iridium complexes represented by (G8).

[0202] [ka]

[0203] In the above general formula (G7), Ar 1 is a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. The aryl group having 6 to 13 carbon atoms includes a phenyl group, a naphthyl group, a biphenyl group, and a phenyl group. Specific examples of the aryl group include an aryl group and a fluorenyl group. When the substituent is present, the substituent is an alkyl group having 1 to 6 carbon atoms, an alkyl group having 3 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. Specific examples of alkyl groups having 1 to 6 carbon atoms include methyl groups. propyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl Examples of the cycloalkyl group include a cycloalkyl group having 3 to 6 carbon atoms, an n-ethyl group, and an n-hexyl group. Specific examples of alkyl groups include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, Examples of the aryl group having 6 to 13 carbon atoms include a cyclohexyl group. Specific examples of the alkyl group include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. It is possible.

[0204] Also, R 1 ~R 4 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms; Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, and a methyl group. propyl, isopropyl, butyl, isobutyl, tert-butyl, n -hexyl group, etc. Furthermore, cycloalkyl groups having 3 to 6 carbon atoms, Specific examples of the alkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cyclohexyl group. Examples of the aryl group having 6 to 13 carbon atoms include phenyl groups and the like. Specific examples include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. In addition, R 1 ~R 4 The fact that it is all hydrogen makes it easy to synthesize and the cost of raw materials. It is advantageous.

[0205] Also, R 6 represents hydrogen, an alkyl group having 1 to 6 carbon atoms, or a haloalkyl group having 1 to 6 carbon atoms. or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, and an isopropyl group. Examples of suitable alkyl groups include butyl, isobutyl, tert-butyl, and n-hexyl groups. The haloalkyl group having 1 to 6 carbon atoms is preferably a group having at least one hydrogen atom. Alkyl groups substituted with group 17 elements (fluorine, chlorine, bromine, iodine, astatine) alkyl fluoride, alkyl chloride, alkyl bromide, alkyl iodide Specifically, methyl fluoride group, methyl chloride group, ethyl fluoride group, ethylene chloride group, etc. The number or type of halogen atoms contained in each of these groups is The aryl group having 6 to 13 carbon atoms may be one or more. Specific examples include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. Furthermore, the aryl group may have substituents, and the substituents may be bonded to each other. The substituent may be an alkyl group having 1 to 6 carbon atoms, a group having 3 or more carbon atoms, or a group having 4 or more carbon atoms. A cycloalkyl group having from 6 to 6 carbon atoms or an aryl group having from 6 to 13 carbon atoms is also selected as a substituent. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, Propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, n-hexyl group Examples of the cycloalkyl group having 3 to 6 carbon atoms include a cycloalkyl group and a cycloalkyl group. Specifically, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, etc. Examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, Specific examples include a naphthyl group, a biphenyl group, and a fluorenyl group.

[0206] Also, Ar 1 , R 1 ~R 4 , and R 6 and an aryl group represented by R 1 ~R 4 Less One of them has a cyano group.

[0207] [ka]

[0208] In the above general formula (G8), R 7 and R 11 represents an alkyl group having 1 to 6 carbon atoms; , R 7 and R 11 The alkyl groups having 1 to 6 carbon atoms are specifically Specifically, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, Examples include a tert-butyl group and an n-hexyl group.

[0209] Also, R 8 ~R 10 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, a substituted or unsubstituted phenyl group, or a cyano group; Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, Propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, n-hexyl group Examples of cycloalkyl groups having 3 to 6 carbon atoms include cycloalkyl groups such as cycloalkyl groups having 3 to 6 carbon atoms and cycloalkyl groups having 6 to 6 carbon atoms. Specifically, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group In addition, R 8 ~R 10 At least one of the groups has a cyano group. It is preferable.

[0210] Also, R 1 ~R 4 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms; Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, and a methyl group. propyl, isopropyl, butyl, isobutyl, tert-butyl, n -hexyl group, etc. Furthermore, cycloalkyl groups having 3 to 6 carbon atoms, Specific examples of the alkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cyclohexyl group. Examples of the aryl group having 6 to 13 carbon atoms include phenyl groups and the like. Specific examples include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. In addition, R 1 ~R 4 The fact that it is all hydrogen makes it easy to synthesize and the cost of raw materials. It is advantageous.

[0211] Also, R 6 represents hydrogen, an alkyl group having 1 to 6 carbon atoms, or a haloalkyl group having 1 to 6 carbon atoms. or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, and an isopropyl group. Examples of suitable alkyl groups include butyl, isobutyl, tert-butyl, and n-hexyl groups. The haloalkyl group having 1 to 6 carbon atoms is preferably a group having at least one hydrogen atom. Alkyl groups substituted with group 17 elements (fluorine, chlorine, bromine, iodine, astatine) alkyl fluoride, alkyl chloride, alkyl bromide, alkyl iodide Specifically, methyl fluoride group, methyl chloride group, ethyl fluoride group, ethylene chloride group, etc. The number or type of halogen atoms contained in each of these groups is The aryl group having 6 to 13 carbon atoms may be one or more. Specific examples include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. Furthermore, the aryl group may have substituents, and the substituents may be bonded to each other. The substituent may be an alkyl group having 1 to 6 carbon atoms, a group having 3 or more carbon atoms, or a group having 4 or more carbon atoms. A cycloalkyl group having from 6 to 6 carbon atoms or an aryl group having from 6 to 13 carbon atoms is also selected as a substituent. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, Propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, n-hexyl group Examples of the cycloalkyl group having 3 to 6 carbon atoms include a cycloalkyl group and a cycloalkyl group. Specifically, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, etc. Examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, Specific examples include a naphthyl group, a biphenyl group, and a fluorenyl group.

[0212] R in the above general formulas (G2) to (G8) 1 ~R 4 Alkyl groups and aryl groups represented by As the group, for example, the groups represented by the above structural formulas (R-1) to (R-29) are applied. The alkyl and aryl groups that can be used are not limited to these. I can't.

[0213] In the general formulae (G1) to (G4) and (G7), Ar 1 A is expressed as Aryl group, and in general formula (G1), Ar 2 Examples of the aryl group represented by the formula: Groups represented by the above structural formulas (R-12) to (R-29) can be applied. , Ar 1 and Ar 2 The groups that can be used as are not limited to these.

[0214] In addition, R in general formulas (G5), (G6), and (G8) 7 and R 11 Alkyl represented by The group may be, for example, a group represented by the above structural formulas (R-1) to (R-10). However, the groups that can be used as the alkyl group are not limited to these.

[0215] In addition, R in general formulas (G5), (G6), and (G8) 8 ~R 10 Alkyl represented by The group or the substituted or unsubstituted phenyl group can be, for example, a group represented by the above structural formulas (R-1) to (R-2 2) can be used as an alkyl group or a phenyl group. The groups that can be present are not limited to these.

[0216] In addition, R in the above general formulas (G3) to (G6) 5 and general formulas (G4), (G6) to ( G8)R 6 The alkyl group, aryl group, or haloalkyl group represented by the formula (I) is, for example, The structural formulas (R-1) to (R-29) and the structural formulas (R-30) to (R-37) are as follows: In addition, the alkyl group, the aryl group, or the haloalkyl group can be used. The groups that can be used as the alkyl group are not limited to these.

[0217] [ka]

[0218] <Specific examples of iridium complexes> Specific structures of the iridium complexes represented by the above general formulae (G1) to (G8) include Examples of the compound include compounds represented by the following structural formulas (300) to (334). The iridium complexes represented by the general formulae (G1) to (G8) are not limited to the following examples.

[0219] [ka]

[0220] [ka]

[0221] [ka]

[0222] [ka]

[0223] [ka]

[0224] [ka]

[0225] As described above, the iridium complexes exemplified above have relatively low HOMO levels and LU Since the compound has an MO level, it is suitable as a guest material for the light-emitting element of one embodiment of the present invention. This makes it possible to manufacture a light-emitting element with good luminous efficiency. Iridium complexes have a high triplet excited energy level, making them particularly suitable for blue light-emitting elements. This makes it possible to fabricate blue light-emitting devices with good luminous efficiency. In addition, the iridium complexes exemplified above are suitable for repeated oxidation and reduction. Since the iridium complex has good resistance, the use of the iridium complex in a light-emitting element can improve the operating life. A good light-emitting device can be fabricated.

[0226] In addition, materials that can be used as the host material 133 in the light-emitting layer 130 include: A combination capable of forming an exciplex with the host material 132 is preferred. Highly donating structures such as aromatic heterocyclic structures and aromatic amine structures, or π-electron deficient structures It is preferable that the compound has at least one skeleton having a high acceptor property, such as a heteroaromatic ring skeleton. The compounds having a π-electron-rich heteroaromatic ring skeleton include the dibenzothiophene mentioned above. heteroaromatic compounds such as benzophenone derivatives, dibenzofuran derivatives, and carbazole derivatives. In addition, examples of compounds having a π-electron deficient heteroaromatic ring skeleton include the pyridine compounds mentioned above. derivatives, diazine derivatives (pyrimidine derivatives, pyrazine derivatives, pyridazine derivatives) and In this case, the host material 133 and the heteroaromatic compound 134 are used. The emission peak of the exciplex formed with the host material 132 is Triplet MLCT (Metal to Ligand Charge Trans) fer) transition, more specifically, the absorption band on the longest wavelength side. Selecting a material 132, a host material 133, and a guest material 131 (phosphorescent compound) This makes it possible to obtain a light-emitting device with dramatically improved luminous efficiency. However, when a thermally activated delayed fluorescent material is used instead of a phosphorescent compound, the longest wavelength The side absorption band is preferably a singlet absorption band.

[0227] Materials that can be used for the host material 133 include the hole transporting materials and Specific examples of the electron transporting material include tris(8-quinolinol). Tris(4-methyl-8-quinolinol)aluminum(III) (Alq), ) Aluminum(III) (abbreviation: Almq3), bis(10-hydroxybenzo[h] Quinolinato)beryllium(II) (abbreviation: BeBq2), bis(2-methyl-8-quinolinato)beryllium(II) (4-phenylphenolato)aluminum(III) (abbreviation: BAlq), bis(4-phenylphenolato)aluminum(III) (8-quinolinolato)zinc(II) (abbreviation: Znq), bis[2-(2-benzoxazol- aryl)phenolato]zinc(II) (abbreviation: ZnPBO), bis[2-(2-benzothiazo metal complexes such as 2-(4-biphenyl)phenolato]zinc(II) (abbreviation: ZnBTZ), (phenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole ( Abbreviation: PBD), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4- Oxadiazol-2-yl]benzene (abbreviation: OXD-7), 3-(4-biphenylyl) )-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 2,2',2''-(1,3,5-benzenetriyl)tris(1- phenyl-1H-benzimidazole) (abbreviation: TPBI), bathophenanthroline (abbreviation BPhen), Bathocuproine (BCP), 9-[4-(5-phenyl-1 ,3,4-oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation: CO 11), and heterocyclic compounds such as 4,4'-bis[N-(1-naphthyl)-N-phenylamine]. N,N'-bis(3-methylphenyl) (amino)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviation: TPD), 4,4'-bis[N-(spiro-9,9'-bifluoren-2-yl)-N- Examples of aromatic amine compounds include phenylamino]biphenyl (abbreviation: BSPB) In addition, anthracene derivatives, phenanthrene derivatives, pyrene derivatives, chrysene derivatives, Condensed polycyclic aromatic compounds such as dibenzo[g,p]chrysene derivatives are exemplified. Specific examples thereof include: 9,10-Diphenylanthracene (abbreviation: DPAnth), N,N-diphenyl-9- [4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole-3-amine CzA1PA, 4-(10-phenyl-9-anthryl)triphenylamine DPhPA, 4-(9H-carbazol-9-yl)-4'-(10-phenyl)- N,9-diphenyl-9-anthryl)triphenylamine (abbreviation: YGAPA) -N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole-3 -amine (abbreviation: PCAPA), N,9-diphenyl-N-{4-[4-(10-phenyl {9-(triphenyl)phenyl}-9H-carbazol-3-amine (abbreviated as PCAPBA), N,9-diphenyl-N-(9,10-diphenyl-2-anthryl) -9H-Carbazol-3-amine (abbreviation: 2PCAPA), 6,12-dimethoxy-5 ,11-Diphenylchrysene,N,N,N',N',N'',N'',N''',N'' '-Octaphenyldibenzo[g,p]chrysene-2,7,10,15-tetraamine( Abbreviation: DBC1), 9-[4-(10-phenyl-9-anthryl)phenyl]-9H- Carbazole (abbreviation: CzPA), 3,6-diphenyl-9-[4-(10-phenyl- 9-Anthryl)phenyl]-9H-carbazole (abbreviation: DPCzPA), 9,10- Bis(3,5-diphenylphenyl)anthracene (abbreviation: DPPA), 9,10-di( 2-naphthyl)anthracene (abbreviation: DNA), 2-tert-butyl-9,10-di( 2-naphthyl)anthracene (abbreviation: t-BuDNA), 9,9'-bianthryl (abbreviation: :BANT), 9,9'-(stilbene-3,3'-diyl)diphenanthrene (abbreviation: DPNS), 9,9'-(stilbene-4,4'-diyl)diphenanthrene (abbreviation: D PNS2), 1,3,5-tri(1-pyrenyl)benzene (abbreviation: TPB3), etc. In addition, from among these and known substances, the guest material 131 can be selected from the following. Select one or more materials that have an energy gap larger than the energy gap. Just use it as is.

[0228] The light-emitting layer 130 may be composed of two or more layers. When the light-emitting layer 130 is formed by laminating the first light-emitting layer and the second light-emitting layer in this order from the hole transport layer side, a substance having hole transport properties is used as a host material for the first light-emitting layer, and a substance having hole transport properties is used as a host material for the second light-emitting layer For example, a substance having an electron transport property is used as the light emitting element.

[0229] In the light-emitting layer 130, a guest material 131, a host material 132, and a host material It may contain materials other than 133.

[0230] A fluorescent compound may also be used in the light-emitting layer 130. There are no particular limitations on the fluorescent compound. Although there are no derivatives, anthracene derivatives, tetracene derivatives, chrysene derivatives, and phenanthrene derivatives Conductors, pyrene derivatives, perylene derivatives, stilbene derivatives, acridone derivatives, coumarin derivatives, phenoxazine derivatives, phenothiazine derivatives, etc. are preferred.

[0231] Specifically, 5,6-bis[4-(10-phenyl-9-anthryl)phenyl]-2 ,2'-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl -9-anthryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2 BPy), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoro (9-phenyl)pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn) , N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H -fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMem FLPAPrn), N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl )phenyl]-N,N'-bis(4-tert-butylphenyl)pyrene-1,6-diazo amine (abbreviation: 1,6tBu-FLPAPrn), N,N'-bis[4-(9-phenyl- 9H-fluoren-9-yl)phenyl]-N,N'-diphenyl-3,8-dicyclohexyl Xylpyrene-1,6-diamine (abbreviation: ch-1,6FLPAPrn), N,N'-biphenyl bis[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenylstilbe 4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazol-9-yl) -4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA) , 4-(9H-carbazol-9-yl)-4'-(9,10-diphenyl-2-anthracene) N,9-diphenyl-N-[4- (10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation Name: PCAPA), Perylene, 2,5,8,11-tetra(tert-butyl)perylene (abbreviation: TBP), 4-(10-phenyl-9-anthryl)-4'-(9-phenyl- 9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAPA), N,N' '-(2-tert-butylanthracene-9,10-diyldi-4,1-phenylene) Bis[N,N',N'-triphenyl-1,4-phenylenediamine] (abbreviation: DPAB PA), N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl] phenyl]-9H-carbazol-3-amine (abbreviation: 2PCAPPA), N-[4-(9 ,10-diphenyl-2-anthryl)phenyl]-N,N',N'-triphenyl-1 ,4-Phenylenediamine (abbreviation: 2DPAPPA), N,N,N',N',N'',N '',N''',N'''-Octaphenyldibenzo[g,p]chrysene-2,7,10 ,15-tetraamine (abbreviation: DBC1), Coumarin 30, N-(9,10-diphenyl -2-anthryl)-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2 PCAPA), N-[9,10-bis(1,1'-biphenyl-2-yl)-2-anthracene] aryl]-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCABPh A), N-(9,10-diphenyl-2-anthryl)-N,N',N'-triphenyl -1,4-phenylenediamine (abbreviation: 2DPAPA), N-[9,10-bis(1,1 '-biphenyl-2-yl)-2-anthryl]-N,N',N'-triphenyl-1, 4-Phenylenediamine (abbreviation: 2DPABPhA), 9,10-bis(1,1'-biphenyl) (9H-carbazol-9-yl)phenyl)-N-[4-(9H-carbazol-9-yl)phenyl]-N- Phenylanthracene-2-amine (abbreviation: 2YGABPhA), N,N,9-triphenyl Dianthracen-9-amine (abbreviation: DPhAPhA), Coumarin 6, Coumarin 545T , N,N'-diphenylquinacridone (abbreviation: DPQd), rubrene, 2,8-di-te rt-Butyl-5,11-bis(4-tert-butylphenyl)-6,12-diphenyl Tetrathracene (abbreviation: TBRb), Nile Red, 5,12-bis(1,1'-biphenyl) 2-(2-(2-phenyl-4-yl)-6,11-diphenyltetracene (abbreviation: BPT), [4-(dimethylamino)phenyl]ethenyl}-6-methyl-4H-pyran-4-yl 2-(2-methyl-6-[(2,3-dimethyl- ... ,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl ]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCM2), N,N,N ',N'-Tetrakis(4-methylphenyl)tetracene-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-N,N,N',N'-tetrakis(4-methyl phenyl)acenaphtho[1,2-a]fluoranthene-3,10-diamine (abbreviation: p -mPhAFD), 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl 2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl )ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTI) , 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3, 6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl] -4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTB), 2-(2, 6-Bis{2-[4-(dimethylamino)phenyl]ethenyl}-4H-pyran-4-yl 2-(2,6-bis[2-(8- Methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H -benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}p Dopanedinitrile (abbreviation: BisDCJTM), 5,10,15,20-tetraphenyl Bisbenzo[5,6]indeno[1,2,3-cd:1',2',3'-lm]perylene , etc.

[0232] In addition, as the guest material 131, triplet excitation energy is converted to singlet excitation energy. Any material that has the function of converting triplet excitation energy into singlet excitation energy is acceptable. In addition to phosphorescent compounds, thermally activated delayed fluorescence (TDF) compounds are also known as materials that can convert light. mally activated delayed fluorescence:TAD F) materials. Thermally activated delayed fluorescent materials are materials in which the difference between the S1 level and the T1 level is The triplet excitation energy is converted to the singlet excitation energy by reverse intersystem crossing. Therefore, it is possible to convert triplet excitation energy into a small amount of thermal energy. The energy can be upconverted to singlet excitation energy (reverse intersystem crossing), It is possible to efficiently exhibit luminescence (fluorescence) from the doublet excited state. The term "compound" may be read as "thermally activated delayed fluorescent material." The condition for efficient thermally activated delayed fluorescence is that the energy difference between the S1 and T1 levels is is preferably greater than 0 eV and less than 0.2 eV, and more preferably greater than 0 eV and less than 0. The electron energy is 1 eV or less.

[0233] In addition, materials that exhibit thermally activated delayed fluorescence can be synthesized by themselves through reverse intersystem crossing from the triplet excited state. The thermally activated delayed fluorescent material may be a material capable of generating a doublet excited state. When the substrate is made of, for example, the following materials can be used:

[0234] First, fullerene and its derivatives, acridine derivatives such as proflavine, and eosin are listed. In addition, magnesium (Mg), zinc (Zn), cadmium (Cd), tin (S n), platinum (Pt), indium (In), or palladium (Pd) Examples of the metal-containing porphyrin include protoporphyrin. Porphyrin-tin fluoride complex (SnF2(Proto IX)), mesoporphyrin-fluoride Tin complex (SnF2(Meso IX)), hematoporphyrin-tin fluoride complex (Sn F2 (Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride Complex (SnF2(Copro III-4Me)), Octaethylporphyrin-Fluoride Tin complex (SnF2(OEP)), etioporphyrin-tin fluoride complex (SnF2(E tio I)), octaethylporphyrin-platinum chloride complex (PtCl2OEP), etc. It can be obtained.

[0235] In addition, as a thermally activated delayed fluorescent material composed of one kind of material, π-electron-rich heteroaromatic Heterocyclic compounds having an aromatic skeleton and a π-electron-deficient heteroaromatic skeleton can also be used. Specifically, 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[ 2,3-a]carbazol-11-yl)-1,3,5-triazine (abbreviation: PIC-T RZ), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-3-yl] 4,6-diphenyl-1,3,5-triazine (abbreviated as '4,6-diphenyl-1,3,5-triazine- ...') Name: PCCzPTzn), 2-[4-(10H-phenoxazin-10-yl)phenyl ]-4,6-diphenyl-1,3,5-triazine (abbreviation: PXZ-TRZ), 3-[4 -(5-phenyl-5,10-dihydrophenazin-10-yl)phenyl]-4,5- Diphenyl-1,2,4-triazole (abbreviation: PPZ-3TPT), 3-(9,9-diphenyl Methyl-9H-acridin-10-yl)-9H-xanthen-9-one (Acr XTN), bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl] Sulfone (abbreviation: DMAC-DPS), 10-phenyl-10H,10'H-spiro[a clidin-9,9'-anthracene]-10'-one (abbreviation: ACRSA), etc. The heterocyclic compound has a π-electron rich heteroaromatic skeleton and a π-electron deficient heteroaromatic skeleton. Since the π-electron-rich heteroaromatic aromatic compound has a high electron transporting property and a high hole transporting property, it is preferable. A substance in which a heteroaromatic skeleton is directly bonded to a π-electron-deficient heteroaromatic skeleton is called a π-electron-rich heteroaromatic The donor property of the skeleton and the acceptor property of the π-electron-deficient heteroaromatic skeleton are both strong, and the S1 level and This is particularly preferable because the difference in T1 level becomes small.

[0236] <Pair of electrodes> The electrode 101 and the electrode 102 have the function of injecting holes and electrons into the light-emitting layer 130. The electrodes 101 and 102 are made of metals, alloys, conductive compounds, and mixtures or laminates thereof. It can be formed using aluminum (Al) as a typical example of a metal. , and other transition metals such as silver (Ag), tungsten, chromium, molybdenum, copper, and titanium. , alkali metals such as lithium (Li) and cesium, calcium, magnesium (Mg) Group 2 metals such as ytterbium (Yb) can be used as transition metals. A rare earth metal may be used. As the alloy, an alloy containing the above metals may be used. Examples of the conductive compound include MgAg and AlLi. Indium tin oxide (ITO), silicon or silicon oxide Including indium tin oxide (ITSO), indium zinc oxide (Indium Zinc Oxide) inc Oxide), tungsten and zinc-containing indium oxide, etc. As the conductive compound, an inorganic carbon material such as graphene may be used. As described above, electrodes 101 and 102 are formed by stacking multiple layers of these materials. 2 or both may be formed.

[0237] The light emitted from the light-emitting layer 130 is emitted from one or both of the electrodes 101 and 102. Therefore, at least one of the electrodes 101 and 102 is visible. Conductive materials that have the function of transmitting light include those that transmit visible light. The transmittance is 40% or more and 100% or less, preferably 60% or more and 100% or less, and the resistance Resistivity is 1×10 -2 Electrically conductive materials with a conductivity of Ω·cm or less are also used. The electrode is made of a conductive material that has the function of transmitting and reflecting light. The conductive material has a visible light reflectance of 20% or more and 80% or less, preferably 4 0% or more and 70% or less, and the resistivity is 1×10 -2 Conductive materials with a resistance of Ω·cm or less When a material with low optical transparency, such as a metal or alloy, is used for the electrode that extracts light, The electrode 10 is formed with a thickness (for example, 1 nm to 10 nm) that allows visible light to pass through. Either or both of the electrode 101 and the electrode 102 may be formed.

[0238] In this specification and the like, the electrode having the function of transmitting light includes an electrode having the function of transmitting visible light. It is sufficient to use a material that has both functionality and conductivity, such as the above-mentioned ITO. In addition to the oxide conductor layer, an oxide semiconductor layer or an organic conductor layer containing an organic material is included. The organic conductive layer containing an organic substance may be, for example, a layer containing an organic compound and an electron donor. A layer containing a composite material obtained by mixing an organic compound and an electron acceptor. The resistivity of the transparent conductive layer is preferably 1×10 5Ω·cm or less, more preferably 1×10 4 Ω·cm or less.

[0239] The electrode 101 and the electrode 102 may be formed by a sputtering method, a vapor deposition method, a printing method, or the like. Coating method, MBE (Molecular Beam Epitaxy) method, CVD method, Pulse Laser deposition method, ALD (Atomic Layer Deposition) method, etc. It can be used as appropriate.

[0240] <Hole injection layer> The hole injection layer 111 is formed by injecting holes from one of the pair of electrodes (electrode 101 or electrode 102). It has the function of promoting hole injection by reducing the injection barrier, and is used in materials such as transition metal oxides and fluorine. It is formed by phthalocyanine derivatives or aromatic amines. Examples include molybdenum oxide, vanadium oxide, ruthenium oxide, and tungsten oxide. , manganese oxide, etc. Phthalocyanine derivatives include phthalocyanine, Examples of aromatic amines include benzidine derivatives and phenyl Diamine derivatives, etc. Polymer compounds such as polythiophene and polyaniline Materials such as self-doped polythiophenes, poly(ethylenediamines), can also be used. Typical examples include poly(oxythiophene) / poly(styrenesulfonic acid).

[0241] The hole injection layer 111 is made of a compound material including a hole transporting material and a material that exhibits electron accepting properties. Alternatively, a layer containing a material exhibiting electron accepting properties and a layer containing a material exhibiting electron accepting properties may be used. A stack of layers containing hole transport materials may also be used. It is possible to exchange charges in the presence of a magnetic field. Materials that exhibit electron-accepting properties include quinodimethane. Organic acceptors such as benzophenone derivatives, chloranil derivatives, and hexaazatriphenylene derivatives Specifically, 7,7,8,8-tetracyano-2,3,5,6- Tetrafluoroquinodimethane (abbreviation: F4-TCNQ), chloranil, 2,3,6,7, 10,11-Hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation These compounds have electron-withdrawing groups (halogen groups or cyano groups), such as hydroxybenzoates (HAT-CN). In addition, transition metal oxides, for example, oxides of metals from Groups 4 to 8, can be used. In general, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, These include tungsten oxide, manganese oxide, and rhenium oxide. Among these, it is preferred because it is stable, has low hygroscopicity, and is easy to handle.

[0242] As the hole transporting material, a material having a higher hole transporting property than an electron transporting property can be used. x10 -6 cm 2 It is preferable that the material has a hole mobility of 1 / Vs or more. The aromatic amines and amines listed as hole transporting materials that can be used in the light-emitting layer 130 are Carbazole derivatives can be used. Aromatic hydrocarbons and stilbene derivatives can also be used. The hole transporting material may be a polymer compound.

[0243] Examples of aromatic hydrocarbons include 2-tert-butyl-9,10-di(2-naphthyl) 2-tert-butyl-9,10-di(1-methyl-2-methyl-1,3-diphenyl ... -naphthyl)anthracene, 9,10-bis(3,5-diphenylphenyl)anthracene DPPA, 2-tert-butyl-9,10-bis(4-phenylphenyl) ) anthracene (abbreviation: t-BuDBA), 9,10-di(2-naphthyl)anthracene (Abbreviation: DNA), 9,10-diphenylanthracene (Abbreviation: DPAnth), 2-t ert-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-nathyl)phenyl]anthracene anthracene, 2,3,6,7-tetramethyl-9,10-di(2-naphthyl) Anthracene, 9,9'-bianthryl, 10,10'-diphenyl-9,9'-bianthryl tolyl, 10,10'-bis(2-phenylphenyl)-9,9'-bianthryl, 10 ,10'-bis[(2,3,4,5,6-pentaphenyl)phenyl]-9,9'-bis Anthracene, Anthracene, Tetracene, Rubrene, Perylene, 2,5,8,11-Tetracene (tert-butyl)perylene, etc. In addition, pentacene, coronene, etc. can also be used. In this way, 1×10 -6 cm 2 / Vs or more It is more preferable to use an aromatic hydrocarbon having 14 to 42 carbon atoms.

[0244] The aromatic hydrocarbon may have a vinyl skeleton. Examples of aromatic hydrocarbons include 4,4'-bis(2,2-diphenylvinyl)biphenyl. (abbreviation: DPVBi), 9,10-bis[4-(2,2-diphenylvinyl)phenyl] anthracene (abbreviation: DPVPA), etc.

[0245] In addition, poly(N-vinylcarbazole) (abbreviation: PVK) and poly(4-vinyltriphenyl ether) Nylamine) (abbreviation: PVTPA), poly[N-(4-{N'-[4-(4-diphenyl amino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide]( abbreviation: PTPDMA), poly[N,N'-bis(4-butylphenyl)-N,N'-bis Polymer compounds such as [(phenyl)benzidine] (abbreviation: Poly-TPD) can also be used. can.

[0246] <Hole transport layer> The hole transport layer 112 is a layer containing a hole transport material. The hole transport layer 112 is formed by injecting the hole into the hole injection layer 111. Since it has a function of transporting holes to the light-emitting layer 130, it has the same HOMO level as the hole injection layer 111. It is preferable that the HOMO level is the same as or close to the HOMO level.

[0247] The hole transport material may be any of the materials exemplified as the material for the hole injection layer 111. Also, 1×10 -6 cm 2 / Vs or more. However, other materials may be used as long as they have a higher hole transporting property than an electron transporting property. The layer containing a substance with a high hole transporting property may be not only a single layer but also a layer containing the above-mentioned substance. Two or more layers may be laminated.

[0248] ≪Electron transport layer≫ The electron transport layer 118 is connected to the other of the pair of electrodes (electrode 101 or electrode 102) via the electron injection layer 119. The electron transport material has the function of transporting electrons injected from the electrode 102 to the light-emitting layer 130. As the material, a material with higher electron transportability than holes can be used, and the -6 cm 2 It is preferable that the material has an electron mobility of 1 / Vs or more. As materials (materials with electron transport properties), metal complexes containing zinc or aluminum, and nitrogen-containing π-electron deficient heteroaromatic compounds such as π-electron deficient heteroaromatic compounds can be used. Specifically, the quinoline derivatives listed as electron transport materials that can be used in the light-emitting layer 130 are benzoquinoline, oxazole, or thiazole ligands Metal complexes are also included. Oxadiazole derivatives, triazole derivatives, phenanthroline derivatives, etc. Examples include thoridine derivatives, pyridine derivatives, bipyridine derivatives, and pyrimidine derivatives. Also, 1×10 -6 cm 2 It is preferable that the material has an electron mobility of 1 / Vs or more. Note that, as long as a substance has a higher electron transporting property than a hole transporting property, a substance other than those mentioned above can be used as the electron transporting layer. The electron transport layer 118 may be formed not only as a single layer but also as a layer made of the above-mentioned material. Two or more layers may be laminated.

[0249] In addition, a layer for controlling the movement of electron carriers is provided between the electron transport layer 118 and the light emitting layer 130. The layer for controlling the movement of electron carriers may be made of a material having high electron transport properties as described above. A layer in which a small amount of a substance with high electron trapping properties is added to the By doing so, it becomes possible to adjust the carrier balance. Suppression of problems caused by electrons penetrating the optical layer (such as reduced device lifespan) has a great effect on.

[0250] ≪Electron injection layer≫ The electron injection layer 119 promotes electron injection by reducing the electron injection barrier from the electrode 102. For example, Group 1 metals, Group 2 metals, or their oxides and halides In addition, the electron transport material and the corresponding electron transport material can be used. A composite material of a material exhibiting electron donating properties can also be used. Examples include Group 1 metals, Group 2 metals, and oxides thereof. are lithium fluoride (LiF), sodium fluoride (NaF), and cesium fluoride (CsF ), calcium fluoride (CaF2), lithium oxide (LiO x ) and other alkaline gold Metals, alkaline earth metals, or compounds thereof can be used. A rare earth metal compound such as erbium (ErF3) can be used. An electride may be used for 119. The electride may be, for example, calcium. Examples include a material in which electrons are highly concentrated in a mixed oxide of aluminum and silicon. The injection layer 119 may be made of a material that can be used in the electron transport layer 118 .

[0251] The electron injection layer 119 may contain a composite material formed by mixing an organic compound and an electron donor (donor). Such composite materials may be formed by electron donors giving electrons to organic compounds. In this case, the organic compound is It is preferable that the material is excellent in transporting the generated electrons. Specifically, for example, the above-mentioned The material constituting the electron transport layer 118 (metal complex, heteroaromatic compound, etc.) can be used. The electron donor may be any substance that exhibits electron donating properties to organic compounds. For the metal, alkali metals, alkaline earth metals and rare earth metals are preferred, and lithium, cesium, Examples include magnesium, calcium, erbium, and ytterbium. Preferred are lithium metal oxides and alkaline earth metal oxides, and lithium oxide and calcium oxide are preferred. , barium oxide, etc. Also, Lewis bases such as magnesium oxide are used. It is also possible to use organic compounds such as tetrathiafulvalene (abbreviation: TTF). It can also be done as follows.

[0252] The above-mentioned light-emitting layer, hole-injection layer, hole-transport layer, electron-transport layer, and electron-injection layer are These are deposition method (including vacuum deposition method), inkjet method, coating method, and nozzle printing method, respectively. The light-emitting layer and the hole-injection layer can be formed by a method such as gravure printing. In addition to the above-mentioned materials, the hole transport layer, the electron transport layer, and the electron injection layer may contain other materials such as quantum dots. Inorganic compounds or polymeric compounds (oligomers, dendrimers, polymers, etc.) may be used. stomach.

[0253] Quantum dots include colloidal quantum dots, alloy quantum dots, and core-shell quantum dots. It is also possible to use quantum dots of the 2nd group and the 16th group, quantum dots of the 13th group, and the like. Contains element groups from group 15, 13 and 17, 11 and 17, or 14 and 15 Quantum dots may also be used. Alternatively, cadmium (Cd), selenium (Se), zinc (Zn ), sulfur (S), phosphorus (P), indium (In), tellurium (Te), lead (Pb), gallium Quantum dots containing elements such as Ga, As, and Al are used. It's fine.

[0254] Examples of liquid media used in wet processes include methyl ethyl ketone, cyclohexane, and the like. Ketones such as xanone, fatty acid esters such as ethyl acetate, halogens such as dichlorobenzene aromatic hydrocarbons, toluene, xylene, mesitylene, cyclohexylbenzene, etc. Hydrocarbons, aliphatic hydrocarbons such as cyclohexane, decalin, and dodecane, dimethylformamide Organic solvents such as dimethyl amide (DMF) and dimethyl sulfoxide (DMSO) can be used. Cut.

[0255] Furthermore, examples of polymer compounds that can be used in the light-emitting layer include poly[2-methacrylamide] and poly[2-methyl-2-propanol]. 5-(2-ethylhexyloxy)-1,4-phenylene vinylene] (abbreviation: MEH -PPV), polyphenylene such as poly(2,5-dioctyl-1,4-phenylene vinylene) Poly(9,9-di-n-octylfluorenyl-2,7-diol) -diyl) (abbreviation: PF8), poly[(9,9-di-n-octylfluorenyl-2,7 -diyl)-alt-(benzo[2,1,3]thiadiazole-4,8-diyl)](abbreviation Name: F8BT), poly[(9,9-di-n-octylfluorenyl-2,7-diyl)- alt-(2,2'-bithiophene-5,5'-diyl)] (abbreviated as F8T2), poly[( 9,9-Dioctyl-2,7-divinylenefluorenylene)-alt-(9,10-an thracene)], poly[(9,9-dihexylfluorene-2,7-diyl)-alt-( polyfluorene derivatives such as poly(3-hexyl) Polyalkylthiophenes (P) such as silthiophene-2,5-diyl (abbreviation: P3HT) AT) derivatives, polyphenylene derivatives, etc. Furthermore, these polymer compounds, Poly(9-vinylcarbazole) (abbreviation: PVK), poly(2-vinylnaphthalene), poly Tri[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (abbreviation: PTA A) or the like polymer compound may be doped with a light-emitting compound and used in the light-emitting layer. As the compound, the above-mentioned luminescent compounds can be used.

[0256] <Substrate> Furthermore, the light-emitting element according to one embodiment of the present invention may be formed on a substrate made of glass, plastic, or the like. As for the order of fabrication on the substrate, the layers may be stacked in order from the electrode 101 side. They may be stacked in order from the pole 102 side.

[0257] The substrate on which the light-emitting element according to one embodiment of the present invention can be formed is, for example, glass or quartz. Alternatively, a flexible substrate may be used. The substrate is a flexible substrate, such as polycarbonate. Examples of suitable substrates include plastic substrates made of polyacrylate and polyarylate. It is also possible to use a metal-deposited film. Any other material may be used as long as it functions as a support in the light-emitting device. Anything that has the function of protecting the element and the optical element may be used.

[0258] For example, in the present invention, a light emitting element can be formed using various substrates. The type of substrate is not particularly limited. An example of the substrate is a semiconductor substrate (e.g., a single crystal substrate or silicon substrate), SOI substrate, glass substrate, quartz substrate, plastic substrate, metal Substrate, stainless steel substrate, substrate with stainless steel foil, tungsten substrate, tungsten foil substrate, flexible substrate, laminated film, fibrous These include cellulose nanofibers (CNF), paper, and base films that contain these materials. Examples of glass substrates include barium borosilicate glass, aluminoborosilicate glass, or Soda lime glass, etc. Flexible substrates, laminated films, base films, etc. Examples include polyethylene terephthalate (PET), poly Polyethylene naphthalate (PEN), polyethersulfone (PES), polytetrafluoroethylene Examples of plastics include PTFE (Polyterephthalate) and acrylic. Resins such as acrylic resins are also available. Examples include polypropylene, polyester, and Examples include polyvinyl fluoride, polyvinyl chloride, etc. Alternatively, examples include polyamide, Examples include polyimide, aramid, epoxy, inorganic vapor deposition film, and paper.

[0259] Alternatively, a flexible substrate may be used as the substrate, and the light emitting element may be formed directly on the flexible substrate. Alternatively, a release layer may be provided between the substrate and the light-emitting element. After a part or all of a device is completed, it is separated from the substrate and used to transfer it to another substrate. In this case, the light-emitting element can be transferred onto a substrate having poor heat resistance or a flexible substrate. The peeling layer may have a laminated structure of inorganic films, such as a tungsten film and a silicon oxide film. or a structure in which a resin film such as polyimide is formed on a substrate, etc., can be used.

[0260] That is, a light emitting element is formed using a certain substrate, and then the light emitting element is transferred to another substrate. The light emitting element may be disposed on another substrate. In addition to the substrates mentioned above, cellophane substrates, stone substrates, wood substrates, fabric substrates (natural fibers (silk, cotton, Hemp), synthetic fibers (nylon, polyurethane, polyester) or regenerated fibers (acetate (including cellulose, cupro, rayon, recycled polyester, etc.), leather substrate, rubber substrate, etc. By using these substrates, it is possible to produce light emitting elements that are durable and highly heat resistant. The light emitting element may be a small, lightweight, or thin light emitting element.

[0261] Furthermore, for example, a field effect transistor (FET) is formed on the above-mentioned substrate, and the FET and The light emitting element 150 may be fabricated on the electrically connected electrodes. In this way, an active matrix display device that controls the driving of light emitting elements can be manufactured.

[0262] As described above, the structure shown in this embodiment mode can be used in appropriate combination with other embodiment modes. Cut.

[0263] (Embodiment 2) In this embodiment mode, a light-emitting element having a different structure from that shown in Embodiment 1 and The light emitting mechanism of the light emitting element will be explained below with reference to FIG. The parts with the same functions as those indicated by the symbols in 1 are given the same hatch pattern and the symbols are omitted. In addition, parts having similar functions are denoted by similar reference numerals, and their detailed explanations are omitted. may be omitted.

[0264] <Configuration example of light-emitting element> FIG. 5 is a schematic cross-sectional view of the light emitting element 250. As shown in FIG.

[0265] The light-emitting element 250 shown in FIG. 5 has a plurality of electrodes between a pair of electrodes (electrode 101 and electrode 102). 5, the light-emitting unit 106 and the light-emitting unit 108. One light-emitting unit has a structure similar to that of the EL layer 100 shown in FIG. The light emitting element 150 shown in FIG. 1 has one light emitting unit, and the light emitting element 250 shown in FIG. The light emitting element 250 has a plurality of light emitting units. The following description will be given assuming that the electrode 101 functions as a cathode and the electrode 102 functions as a cathode. The structure may be reversed.

[0266] In addition, in the light-emitting element 250 shown in FIG. 5, the light-emitting unit 106 and the light-emitting unit 108 The light-emitting unit 106 and the light-emitting unit 108 are stacked together, and a charge generating layer 1 is provided between the light-emitting unit 106 and the light-emitting unit 108. The light-emitting units 106 and 108 may have the same configuration but different For example, the light-emitting unit 106 may have a structure similar to that of the EL layer 100 shown in FIG. It is preferable to use a composition.

[0267] The light emitting element 250 has a light emitting layer 130 and a light emitting layer 140. In addition to the light-emitting layer 130, the knit 106 includes a hole injection layer 111, a hole transport layer 112, an electron transport layer The light-emitting unit 108 also includes a light-emitting layer 140. In addition to the above, a hole injection layer 116, a hole transport layer 117, an electron transport layer 118, and an electron injection layer 11 It has 9.

[0268] The charge generation layer 115 is formed by adding an acceptor material, which is an electron acceptor, to a hole transport material. Even if the electron transport material is an electron donor, a donor material may be added to the electron transport material. Alternatively, both of these structures may be stacked.

[0269] When the charge generation layer 115 contains a composite material of an organic compound and an acceptor substance, the The composite material that can be used for the hole-injection layer 111 shown in Embodiment 1 is used as the composite material. The organic compounds include aromatic amine compounds, carbazole compounds, aromatic carbonized compounds, and the like. Various compounds such as hydrogen and polymer compounds (oligomers, dendrimers, polymers, etc.) are used. As for organic compounds, those with a hole mobility of 1×10 -6 cm 2 / Vs However, it is preferable to use a substance having a higher hole transporting property than an electron transporting property. Other materials may be used as long as they are compatible with the organic compound and the acceptor material. The material has excellent carrier injection and carrier transport properties, allowing for low voltage and low current operation. In addition, as in the light-emitting unit 108, the surface of the light-emitting unit on the anode side When the charge generating layer 115 is in contact with the charge generating layer 115, the charge generating layer 115 is in contact with the hole injection layer of the light emitting unit. The light-emitting unit can also function as a hole-injection layer or a hole-transport layer. The hole transport layer may not be provided.

[0270] The charge generation layer 115 may be a layer containing a composite material of an organic compound and an acceptor substance, or another layer containing a compound of an organic compound and an acceptor substance. For example, the organic EL element may be formed as a laminated structure in which layers made of the organic EL element are combined. A layer including a composite material of a compound and an acceptor substance and a layer including a compound selected from electron donor substances. The compound may be formed by combining a layer containing the compound with a compound having a high electron transporting property. A layer containing a composite material of an organic compound and an acceptor substance and a layer containing a transparent conductive material are combined. It may also be formed by combining them.

[0271] The charge generating layer 115 sandwiched between the light emitting unit 106 and the light emitting unit 108 When a voltage is applied between the electrode 101 and the electrode 102, electrons are injected into one of the light-emitting units, It is sufficient if it injects holes into the other light-emitting unit. For example, in FIG. When a voltage is applied so that the potential of electrode 101 is higher than the potential of electrode 102, charge generation Layer 115 injects electrons into light-emitting unit 106 and holes into light-emitting unit 108. .

[0272] From the viewpoint of light extraction efficiency, the charge generation layer 115 is transparent to visible light (specifically, It is preferable that the charge generating layer 115 has a visible light transmittance of 40% or more. The charge generating layer 115 has a lower conductivity than the pair of electrodes (electrodes 101 and 102). If the conductivity of the charge generating layer 115 is as high as that of the pair of electrodes, the charge The carriers generated by the generating layer 115 flow in the direction of the film surface, and the electrode 101 and the electrode There are cases where light emission occurs in areas where there is no overlap with 102. To achieve this, the charge generation layer 115 is preferably formed of a material having a lower conductivity than the pair of electrodes. It's nice.

[0273] By forming the charge generating layer 115 using the above-mentioned materials, when a light emitting layer is laminated, In this case, the increase in the driving voltage can be suppressed.

[0274] In addition, although the light emitting element having two light emitting units has been described with reference to FIG. 5, the light emitting element having three light emitting units may be The same can be applied to a light-emitting element in which two or more light-emitting units are stacked. As shown in the light-emitting element 250, a plurality of light-emitting units are separated by a charge generating layer between a pair of electrodes. By arranging the LEDs in this way, high brightness light emission is possible while keeping the current density low, and furthermore, a long life is achieved. Furthermore, a light-emitting element with low power consumption can be realized.

[0275] At least one of the multiple units has the EL layer 100 shown in FIG. By applying the above structure, a light-emitting element with high luminous efficiency can be provided.

[0276] The light-emitting layer 130 of the light-emitting unit 106 has the same structure as that shown in the first embodiment. It is preferable that the light emitting element 250 has the above configuration. It is suitable for children.

[0277] The guest materials used in the light-emitting units 106 and 108 are the same as those used in the light-emitting units 106 and 108. The light-emitting units 106 and 108 may have the same gate. When the light emitting element 250 has a resist material, it exhibits high light emitting brightness with a small current value. In addition, the light-emitting units 106 and 108 may have different guest materials. In this case, the light emitting element 250 becomes a light emitting element that emits multicolor light, which is preferable. The gate is designed to emit white light with high luminance, or at least light having red, green, and blue components. It is preferable to select a stainless steel material.

[0278] The light-emitting unit 106, the light-emitting unit 108, and the charge generating layer 115 are formed by evaporation ( (including vacuum deposition), inkjet printing, coating, gravure printing, etc. can be done.

[0279] Note that the structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. You can be there.

[0280] (Embodiment 3) In this embodiment mode, a light-emitting element having a different structure from those shown in Embodiment Modes 1 and 2 will be described. An example of this will be described below with reference to FIGS.

[0281] <Configuration example 1 of light-emitting element> 6 is a cross-sectional view illustrating a light-emitting element according to one embodiment of the present invention. The same hatch pattern is used for parts with the same function as the symbols shown, and in some cases the symbols are omitted. In addition, parts having similar functions are given similar reference numerals, and detailed explanations thereof will be omitted. It may be omitted.

[0282] The light emitting element 260 shown in FIG. 6 is a bottom-emitting element that extracts light toward the substrate 200. The light emitting element may be a top emission (top emission) type light emitting element that extracts light in the direction opposite to the substrate 200. Note that one embodiment of the present invention is not limited thereto. The light emitted by the light emitting element is emitted from both the upper and lower sides of the substrate 200. The light emitting element may be a dual emission type light emitting element.

[0283] When the light emitting element 260 is a bottom emission type, the electrode 101 has a function of transmitting light. It is also preferable that the electrode 102 has a function of reflecting light. Alternatively, when the light emitting element 260 is a top emission type, the electrode 101 is It is preferable that the electrode 102 has a function of reflecting light. It is preferable to do so.

[0284] The light emitting element 260 has an electrode 101 and an electrode 102 on a substrate 200. Between the electrode 101 and the electrode 102, there are a light-emitting layer 123B, a light-emitting layer 123G, and a light-emitting layer 123R. , a hole injection layer 111, a hole transport layer 112, an electron transport layer 118, and an electron and a child injection layer 119.

[0285] The electrode 101 may be formed of a plurality of conductive layers. and a conductive layer having a function of transmitting light are preferably stacked. .

[0286] The electrode 101 has the same configuration as the electrode 101 or the electrode 102 shown in the first embodiment. and materials can be used.

[0287] In FIG. 6, the region 221B and the region 221G are sandwiched between the electrode 101 and the electrode 102. A partition wall 145 is provided between the region 221R and the region 221R. The partition wall 145 has insulating properties. The partition wall 145 covers the end of the electrode 101 and has an opening that overlaps with the electrode. By doing so, the electrodes 101 on the substrate 200 in each region can be separated into islands. It becomes possible.

[0288] The light-emitting layer 123B and the light-emitting layer 123G are mutually separated in the region where they overlap with the partition wall 145. The light-emitting layer 123G and the light-emitting layer 123R may have an overlapping region. In the region overlapping with the wall 145, there may be a region overlapping with each other. The light-emitting layer 23R and the light-emitting layer 123B overlap each other in the region where they overlap with the partition wall 145. It may have.

[0289] The partition wall 145 may be formed using an inorganic or organic material as long as it has insulating properties. The inorganic material may be silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, or the like. Examples of the organic material include silicon, aluminum oxide, and aluminum nitride. For example, photosensitive resin materials such as acrylic resin or polyimide resin can be used.

[0290] The light-emitting layers 123R, 123G, and 123B each exhibit a different color. For example, the light-emitting layer 123R may have a red light-emitting material. By including a light-emitting material having a function of emitting red light, the region 221R emits red light, and the light-emitting layer 12 Since the region 3G has a light-emitting material having a function of emitting green light, the region 221G emits green light. The light-emitting layer 123B contains a light-emitting material that exhibits blue color. B emits blue light. The light emitting element 260 having such a configuration is used as a pixel of a display device. By using these, a display device capable of full color display can be manufactured. The thickness of each light-emitting layer may be the same or different.

[0291] In addition, any one or more of the light-emitting layer 123B, the light-emitting layer 123G, and the light-emitting layer 123R This light-emitting layer preferably has the same structure as the light-emitting layer 130 shown in the first embodiment. In this way, a light-emitting element with high luminous efficiency can be manufactured.

[0292] In addition, any one or more of the light-emitting layer 123B, the light-emitting layer 123G, and the light-emitting layer 123R The light-emitting layer may have a structure in which two or more layers are laminated.

[0293] As described above, at least one light-emitting layer has the light-emitting layer shown in Embodiment 1, and the light-emitting By using the light emitting element 260 having the layer as a pixel of a display device, a display device with high luminous efficiency can be obtained. That is, a display device having the light-emitting element 260 can be manufactured with low power consumption. can be reduced.

[0294] In addition, by providing a color filter on the electrode for extracting light, the color purity of the light emitting element 260 can be improved. Therefore, the color purity of the display device having the light emitting element 260 can be improved. It can be done.

[0295] Furthermore, by providing a polarizing plate on the electrode for extracting light, the reflection of external light from the light emitting element 260 can be reduced. Therefore, the contrast ratio of the display device having the light emitting element 260 can be improved. It can be done.

[0296] Other configurations of the light emitting element 260 are the same as those of the light emitting element in the first embodiment. Please take the configuration into consideration.

[0297] <Configuration example 2 of light-emitting element> Next, regarding a configuration example different from that of the light-emitting element shown in FIG. 6, the following will be described with reference to FIGS. 7(A) and 7(B). Give an explanation.

[0298] 7(A) and 7(B) are cross-sectional views showing a light-emitting element of one embodiment of the present invention. In (B), the parts having the same functions as those shown in FIG. 6 are designated by the same hatch patterns. In addition, parts with similar functions are designated by similar symbols. The detailed description may be omitted.

[0299] 7A and 7B show examples of the structure of a light-emitting element having a light-emitting layer between a pair of electrodes. The light emitting element 262a shown in (A) is a top-emitting (top-emitting) element that extracts light in the direction opposite to the substrate 200. The light emitting element 262b shown in FIG. 7(B) is a top-emission type light emitting element. However, the present invention One embodiment is not limited to this, and light emitted by the light emitting element may be emitted from the substrate 200 on which the light emitting element is formed. It may also be a dual emission type in which light is extracted from both the top and bottom.

[0300] The light emitting element 262a and the light emitting element 262b are formed by providing an electrode 101 and an electrode 102 on a substrate 200. , electrode 103, and electrode 104. Also, between electrode 101 and electrode 102, and At least a light-emitting layer is formed between the electrode 102 and the electrode 103 and between the electrode 102 and the electrode 104. The layer 130 and the charge generating layer 115 are also included. The layer 130 and the charge generating layer 115 are also included. The layer 130 and the charge transport layer 115 are also included. 2, a light-emitting layer 140, an electron transport layer 113, an electron injection layer 114, and a hole injection layer 116. , a hole transport layer 117 , an electron transport layer 118 , and an electron injection layer 119 .

[0301] The electrode 101 includes a conductive layer 101a and a conductive layer 101b that is in contact with the conductive layer 101a. The electrode 103 includes a conductive layer 103a and a conductive layer 103b on and in contact with the conductive layer 103a. The electrode 104 has a conductive layer 104a and a conductive layer 103b on the conductive layer 104a. and an insulating layer 104b.

[0302] The light emitting element 262a shown in FIG. 7(A) and the light emitting element 262b shown in FIG. 7(B) are The area 222B sandwiched between the electrode 101 and the electrode 102, and the area 222B sandwiched between the electrode 102 and the electrode 103 and a region 222R sandwiched between the electrode 102 and the electrode 104. The partition wall 145 has an insulating property. The partition wall 145 is provided between the electrode 101 and the electrode 1 The separator 145 covers the end of the electrode 103 and the electrode 104 and has an opening that overlaps with the electrode. By doing so, the electrodes on the substrate 200 in each region can be separated into islands. This becomes:

[0303] The light emitting element 262a and the light emitting element 262b are arranged in the regions 222B, 222G, and The optical element 224B and the optical element 224C are arranged in the direction in which the light emitted from the region 222R is extracted. The substrate 220 has the optical element 224G and the optical element 224R. The light emitted from the region 222B is emitted to the outside of the light emitting element through each optical element. The light coming from the region 222G is emitted through the optical element 224B. The light emitted through 224G and emitted from the region 222R is reflected by the optical element 224R. It is ejected.

[0304] Furthermore, the optical elements 224B, 224G, and 224R are configured to For example, the optical element 224B has a function of selectively transmitting light of a specific color. The light emitted from the region 222B through the optical element 22 is blue light. The light emitted from the area 222G via the optical element 4G is green light. The light emitted from the region 222R via the element 224R is red light.

[0305] The optical elements 224R, 224G, and 224B may include, for example, a colored layer ( Color filters, bandpass filters, multilayer filters, etc. can be used. In addition, a color conversion element can be applied to the optical element. The color conversion element is an optical element that converts light into light with a longer wavelength than the wavelength of the light. By using quantum dots, the color reproducibility of the display device can be improved. can be increased.

[0306] It should be noted that a plurality of optical elements are provided on the optical element 224R, the optical element 224G, and the optical element 224B. Other optical elements may be provided, such as a circular polarizer or an anti-reflection film. The circular polarizer can be provided on the side of the display device from which light emitted by the light emitting element is extracted. When the display device is turned on, light incident from outside the device is reflected inside the device and emitted to the outside. Furthermore, by providing an anti-reflection film, the phenomenon of reflection on the surface of the display device can be prevented. This can weaken external light, allowing the light emitted by the display device to be clearly observed.

[0307] In addition, in FIG. 7(A)(B), the light emitted from each region via each optical element is Light exhibiting color (B), light exhibiting green (G), and light exhibiting red (R), respectively. This is shown schematically by dashed arrows.

[0308] In addition, a light-shielding layer 223 is provided between each optical element. The light-shielding layer 223 is formed to prevent light from entering from adjacent regions. It should be noted that the light-shielding layer 223 may not be provided. stomach.

[0309] The light-shielding layer 223 has a function of suppressing reflection of external light. The light-shielding layer 223 has a function of preventing the color mixture of light emitted from adjacent light-emitting elements. Examples include metals, resins containing black pigments, carbon black, metal oxides, and multiple metal oxides. A composite oxide containing a solid solution of such a material can be used.

[0310] The substrate 200 and the substrate 220 having the optical element are the same as those in the first embodiment. That's fine.

[0311] Furthermore, the light emitting element 262a and the light emitting element 262b have a microcavity structure. .

[0312] <Microcavity structure> The light emitted from the light-emitting layer 130 and the light-emitting layer 140 is incident on a pair of electrodes (for example, electrode 10 The light emitting layer 130 and the light emitting layer 140 are resonated between the electrode 101 and the electrode 102. For example, the reflection area of ​​the electrode 101 is formed at a position where light of a desired wavelength is intensified. the optical distance from the reflecting area of ​​the electrode 102 to the light emitting area of ​​the light emitting layer 130; By adjusting the optical distance to the light emitting region, the amount of light emitted from the light emitting layer 130 can be reduced. In addition, the light emitted from the reflective region of the electrode 101 to the light-emitting layer 140 can be intensified. and the optical distance from the reflective area of ​​the electrode 102 to the light-emitting area of ​​the light-emitting layer 140. By adjusting the optical distance, it is possible to obtain light of a desired wavelength from the light emitting layer 140. That is, the light can be intensified by using a plurality of light-emitting layers (here, the light-emitting layer 130 and the light-emitting layer In the case of a light emitting device in which the light emitting layer 130 and the light emitting layer 140 are stacked, the optical distances of the light emitting layer 130 and the light emitting layer 140 are It is preferable to optimize the separation.

[0313] In the light emitting element 262a and the light emitting element 262b, the conductive layer (conductive layer 1) is formed in each region. By adjusting the thickness of the light-emitting layer 130, the conductive layer 101b, the conductive layer 103b, and the conductive layer 104b, In addition, it is possible to enhance the light of a desired wavelength among the light emitted from the light emitting layer 140. The thickness of at least one of the hole injection layer 111 and the hole transport layer 112 is made different in the region. By doing so, the light emitted from light-emitting layer 130 and light-emitting layer 140 may be intensified.

[0314] For example, the electrodes 101 to 104 are made of a conductive material having a function of reflecting light. When the refractive index is smaller than that of the light-emitting layer 130 or the light-emitting layer 140, the electrode The thickness of the conductive layer 101b of the electrode 101 is set so that the optical distance between the electrode 101 and the electrode 102 is m B λ B / 2(m B is a natural number, λ B represent the wavelengths of light to be intensified in region 222B, respectively) and Similarly, the thickness of the conductive layer 103b of the electrode 103 is adjusted to be equal to the thickness of the conductive layer 103b of the electrode 103. The optical distance between the electrode 102 is m G λ G / 2(m G is a natural number, λ G is strong in the area 222G The wavelength of the light emitted from the electrode 104 is adjusted to be 100 nm. The thickness of the electrode 104b is set such that the optical distance between the electrode 104 and the electrode 102 is m R λ R / 2(m R is self natural number, λ R and represent the wavelengths of the light to be intensified in the region 222R).

[0315] As described above, a microcavity structure is provided, and the optical distance between a pair of electrodes in each region is adjusted. By adjusting the thickness, light scattering and absorption near each electrode are suppressed, resulting in high light extraction efficiency. In the above structure, the conductive layer 101b and the conductive layer 103 The conductive layer 104b preferably has a function of transmitting light. The materials constituting the conductive layers 103b, 104b may be the same as each other. The conductive layers 101b, 103b, and 104b may be different from each other. Each of these may have a structure in which two or more layers are laminated.

[0316] The light emitting element 262a shown in FIG. 7(A) is a top emission type light emitting element, and therefore is conductive. The layer 101a, the conductive layer 103a, and the conductive layer 104a may have a function of reflecting light. It is also preferable that the electrode 102 has a function of transmitting light and a function of reflecting light. is preferred.

[0317] In addition, the light emitting element 262b shown in FIG. 7B is a bottom emission type light emitting element, and therefore is conductive. The layer 101a, the conductive layer 103a, and the conductive layer 104a have a function of transmitting light and a function of reflecting light. It is preferable that the electrode 102 has a function of reflecting light. preferable.

[0318] In the light-emitting element 262a and the light-emitting element 262b, the conductive layer 101a and the conductive layer 10 The same material may be used for the conductive layer 3a or the conductive layer 104a, or different materials may be used. When the same material is used for the conductive layer 101a, the conductive layer 103a, and the conductive layer 104a, the light emitting element The manufacturing costs of the conductive layer 101a and the light emitting element 262a and the light emitting element 262b can be reduced. The conductive layer 103a and the conductive layer 104a may each have a structure in which two or more layers are stacked. stomach.

[0319] The light-emitting layer 130 in the light-emitting element 262a and the light-emitting element 262b is the same as that in the first embodiment. It is preferable that the structure be the same as that shown in . By doing so, high luminous efficiency can be exhibited. A light-emitting device can be fabricated.

[0320] The light-emitting layer 130 and the light-emitting layer 140 are, for example, the light-emitting layer 140a and the light-emitting layer 140b. In this way, two layers may be laminated on one or both sides. Two types of luminescent materials, a luminescent material and a second luminescent material, which have the function of exhibiting different colors, are used. By using each of them, it is possible to obtain light emission containing multiple colors. The light-emitting material used for each light-emitting layer is selected so that the light emitted by the light-emitting layer 140 becomes white. It is preferable to select

[0321] In addition, the light-emitting layer 130 or the light-emitting layer 140 may have a structure in which three or more layers are laminated on one side or both sides. The light-emitting layer may be made of any material, or may include a layer that does not contain a light-emitting material.

[0322] As described above, the light-emitting element 262a or the light-emitting element 262b having the light-emitting layer structure shown in Embodiment 1 By using the optical element 262b as a pixel of a display device, a display device with high luminous efficiency is manufactured. That is, a display device having the light emitting element 262a or the light emitting element 262b can , power consumption can be reduced.

[0323] Other configurations of the light emitting element 262a and the light emitting element 262b are as follows: 260, or the structures of the light-emitting elements shown in Embodiments 1 and 2 may be taken into consideration. stomach.

[0324] Note that the structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. You can be there.

[0325] (Fourth embodiment) In this embodiment, a display device including a light-emitting element of one embodiment of the present invention will be described with reference to FIGS. 10 will be used to explain.

[0326] <Display device configuration example 1> 8A is a top view showing the display device 600, and FIG. 8B is a diagram showing the display device 600 along the dashed line AB in FIG. 8A. 1 and a cross-sectional view taken along dashed line CD. The display device 600 includes a drive circuit section (signal line The display device includes a driver circuit portion 601, a scanning line driver circuit portion 603, and a pixel portion 602. The signal line driver circuit portion 601, the scanning line driver circuit portion 603, and the pixel portion 602 are It has the function of controlling light emission.

[0327] The display device 600 also includes an element substrate 610, a sealing substrate 604, a sealant 605, The device has an area 607 surrounded by a sealing material 605, wiring 608, and an FPC 609. do.

[0328] The lead wiring 608 is connected to the signal line driver circuit portion 601 and the scanning line driver circuit portion 603. This is the wiring for transmitting the input signal, and is connected to the external input terminal FPC609. It receives the FP signal, clock signal, start signal, reset signal, etc. Although only C609 is shown, FPC609 has a printed wiring board (PWB). A wired wiring board may be installed.

[0329] The signal line driver circuit portion 601 includes an N-channel transistor 623 and a P-channel transistor A CMOS circuit is formed by combining this transistor 624. The path section 601 or the scanning line driving circuit section 603 may be implemented by various CMOS circuits, PMOS circuits, or In this embodiment, a driving circuit section is provided on the substrate. Although the display device shown has the formed driver and pixel on the same surface, this is not necessarily required. In addition, the drive circuit section can be formed externally rather than on the substrate.

[0330] The pixel portion 602 includes a switching transistor 611 and a current control transistor. a lower part electrically connected to the drain of the current control transistor 612; A partition wall 614 is formed to cover the edge of the lower electrode 613. The partition wall 614 can be made of a positive photosensitive acrylic resin film.

[0331] In order to improve the covering property, the partition wall 614 is provided with a curved surface having a curvature at the upper end or the lower end. For example, the partition wall 614 is made of a positive photosensitive acrylic. In this case, only the upper end of the partition wall 614 is curved to have a radius of curvature (0.2 μm or more and 3 μm or less). It is preferable that the partition wall 614 is made of a negative photosensitive resin or a polyimide. Any of the photosensitive resins of the di-type can be used.

[0332] The structure of the transistors (transistors 611, 612, 623, and 624) is For example, a staggered transistor may be used. There is no particular limitation on the polarity, and it has N-channel and P-channel transistors. and either an N-channel transistor or a P-channel transistor. A structure consisting of only one of the two may also be used. For example, an amorphous semiconductor film or a crystalline semiconductor film can be used. Semiconductor materials include group 14 (silicon, etc.) semiconductors, compound semiconductors (oxide As the transistor, for example, An energy gap of 2 eV or more, preferably 2.5 eV or more, and more preferably 3 eV or more By using the oxide semiconductor, the off-state current of the transistor can be reduced. As the oxide semiconductor, In-Ga oxide, In-M-Zn oxide (M is , aluminum (Al), gallium (Ga), yttrium (Y), zirconium (Zr ), lanthanum (La), cerium (Ce), tin (Sn), hafnium (Hf), or nickel Examples include neodymium (Nd).

[0333] An EL layer 616 and an upper electrode 617 are formed on the lower electrode 613. The lower electrode 613 functions as an anode, and the upper electrode 617 functions as a cathode. do.

[0334] The EL layer 616 can be formed by a deposition method (including a vacuum deposition method) using a deposition mask, a droplet discharge method, or the like. (also called inkjet method), coating methods such as spin coating, gravure printing, etc. The EL layer 616 is formed by the method. The material for forming the EL layer 616 is a low molecular weight compound, Alternatively, it may be a polymer compound (including an oligomer or a dendrimer).

[0335] The lower electrode 613, the EL layer 616, and the upper electrode 617 form a light-emitting element 618. The light emitting element 618 has the structure of any one of the first to third embodiments. In addition, when a plurality of light-emitting elements are formed in a pixel portion, the same as those in Embodiments 1 to 4 are preferably used. The light-emitting element according to the third embodiment and the light-emitting element having other structures are both included. That's fine.

[0336] In addition, by bonding the sealing substrate 604 to the element substrate 610 with the sealing material 605, The light-emitting element is disposed in an area 607 surrounded by the element substrate 610, the sealing substrate 604, and the sealing material 605. The region 607 is filled with a filler. In addition to being filled with an inert gas (nitrogen, argon, etc.), it can also be used as a sealing material 605. They may also be filled with UV or heat curable resins that can be used for various applications, such as PVC ( Polyvinyl chloride) resin, acrylic resin, polyimide resin, epoxy resin, Silicone resin, PVB (Polyvinyl Butyral) resin, or EVA (Ethylene Vinyl A recess is formed in the sealing substrate, and a desiccant (acetate) resin is placed therein. By providing this, deterioration due to the influence of moisture can be suppressed, which is a preferable configuration.

[0337] In addition, the optical element 621 is disposed below the sealing substrate 604 so as to overlap the light emitting element 618. In addition, a light-shielding layer 622 is provided below the sealing substrate 604. The optical element and the light-shielding layer 621 and the light-shielding layer 622 are respectively the optical element and the light-shielding layer shown in the third embodiment. The same configuration may be used.

[0338] It is preferable to use epoxy resin or glass frit for the sealing material 605. In addition, it is desirable that these materials be as impermeable to moisture and oxygen as possible. In addition, the material used for the sealing substrate 604 may be a glass substrate, a quartz substrate, or an FRP (Fiber Reinforced Plastic) substrate. Reinforced Plastics), PVF (Polyvinyl Fluoride), Poly A plastic substrate made of ester, acrylic or the like can be used.

[0339] As described above, the light emitting element and the optical element described in any of the first to third embodiments are used. A display device can be obtained.

[0340] <Configuration example 2 of the display device> Next, another example of the display device will be described with reference to FIGS. 9(A) and 9(B) are cross-sectional views of a display device according to one embodiment of the present invention.

[0341] FIG. 9(A) shows a substrate 1001, an underlying insulating film 1002, a gate insulating film 1003, a gate electrode 1004, and a gate electrode 1006. Poles 1006, 1007, 1008, a first interlayer insulating film 1020, and a second interlayer insulating film 102 1, peripheral portion 1042, pixel portion 1040, driving circuit portion 1041, lower electrode 102 of light-emitting element 4R, 1024G, 1024B, partition wall 1025, EL layer 1028, upper electrode 1 of light-emitting element 026, a sealing layer 1029, a sealing substrate 1031, a sealant 1032, and the like are shown.

[0342] In addition, in FIG. 9A, as an example of an optical element, a colored layer (a red colored layer 1034R, a green colored layer 1034R) is used. A transparent substrate 1033 is provided with a colored layer 1034G and a blue colored layer 1034B. A light-shielding layer 1035 may be further provided. The base material 1033 is aligned and fixed to the substrate 1001. The colored layer and the light-shielding layer are 9A, the colored layer is covered with an overcoat layer 1036. The light that passes through is red, green, and blue, so an image can be displayed using three colored pixels.

[0343] In FIG. 9B, as an example of an optical element, a colored layer (a red colored layer 1034R, a green colored layer The blue colored layer 1034G and the blue colored layer 1034B are formed between the gate insulating film 1003 and the first interlayer insulating film. In this example, the colored layer is formed between the substrate 1001 and the sealing substrate 1020. It may be provided between the plates 1031.

[0344] As an example of the optical element, a colored layer (a red colored layer 1034R, a green colored layer 103 4G, a blue colored layer 1034B) is formed between the first interlayer insulating film 1020 and the second interlayer insulating film 102 It may be formed between

[0345] In the display device described above, the substrate 1001 side on which the transistors are formed is The display device has a structure for extracting light (bottom emission type), but The display device may also have a structure in which light is extracted (top emission type).

[0346] <Configuration example 3 of the display device> An example of a cross-sectional view of a top-emission type display device is shown in Figures 10(A) and 10(B). 9(A) and 9(B) are cross-sectional views illustrating a display device of one embodiment of the present invention. 1, the driving circuit section 1041, the peripheral section 1042, etc. are omitted.

[0347] In this case, the substrate 1001 can be a substrate that does not transmit light. Until the connection electrode that connects to the anode of the optical element is fabricated, it is a bottom emission type display device. Then, a third interlayer insulating film 1037 is formed to cover the electrode 1022. This insulating film may also have a role of planarization. In addition to the same material as the interlayer insulating film 2, various other materials can be used.

[0348] The lower electrodes 1024R, 1024G, and 1024B of the light-emitting element are anodes here, but Also, top emission type displays as shown in Figure 10(A)(B) can be used. In the case of a device, the lower electrodes 1024R, 1024G, and 1024B have a function of reflecting light. In addition, an upper electrode 1026 is provided on the EL layer 1028. The electrode 1026 has a function of reflecting light and a function of transmitting light. A microcavity structure is adopted between 24G, 1024B and the upper electrode 1026, It is desirable to increase the light intensity at a particular wavelength.

[0349] In the top emission structure shown in FIG. 10(A), the colored layer (red colored layer 1034 A sealing substrate 1031 provided with a green colored layer 1034R, a green colored layer 1034G, and a blue colored layer 1034B The sealing substrate 1031 has a shielding layer positioned between the pixels. An optical layer 1035 may be provided. Note that the sealing substrate 1031 may be a light-transmitting substrate. It is suitable.

[0350] In addition, in FIG. 10(A), a plurality of light emitting elements and colored light emitting elements are provided. Although the configuration in which a layer is provided is shown as an example, the present invention is not limited to this. For example, as shown in FIG. In this case, the green color layer is not provided, and only the red color layer 1034R and the blue color layer 1034B are provided. It is also possible to use a configuration in which a full color display is performed using three colors, red, green, and blue. In this way, when a light emitting element and a colored layer are provided for each of the light emitting elements, reflection of external light can be reduced. On the other hand, as shown in FIG. 10(B), In the case where a red colored layer and a blue colored layer are provided without providing a colored layer of green, Since there is little energy loss in the light emitted from the light-emitting element, power consumption can be reduced. This has a positive effect.

[0351] The display device described above has a configuration having sub-pixels of three colors (red, green, and blue). A structure with four color sub-pixels (red, green, blue, yellow, or red, green, blue, white) In that case, the function of transmitting yellow light or blue, green, yellow, and red light may be used. It is possible to use a colored layer having a function of transmitting a plurality of lights selected from the following. When the layer has a function of transmitting a plurality of lights selected from blue, green, yellow, and red, the The light transmitted through the colored layer may be white. The light emitting element that emits yellow or white light is Since the light-emitting efficiency is high, a display device having such a configuration can reduce power consumption. Cut.

[0352] The display device 600 shown in FIG. 8 includes an element substrate 610, a sealing substrate 604, and a sealing material. A sealing layer may be formed in the area 607 surrounded by 605. The sealing layer may include, for example, PV C (polyvinyl chloride) resin, acrylic resin, polyimide resin, epoxy resin Fat, silicone resin, PVB (polyvinyl butyral) resin, or EVA (ethylene Resins such as vinyl acetate resins can be used. Silicon oxide, oxynitride, etc. silicon oxide, silicon nitride, silicon nitride, aluminum oxide, aluminum nitride, etc. By forming a sealing layer in the region 607, impurities such as water can be prevented from being generated. It is preferable that the sealing layer is formed so as to suppress deterioration of the light emitting element 618. The sealing material 605 does not have to be provided.

[0353] Furthermore, by forming the sealing layer in multiple layers, impurities such as water can be prevented from entering the display device 600 from the outside. This is preferable because it can effectively prevent the light from reaching the light emitting element 618 inside the device. In addition, when the sealing layer is multi-layered, it is preferable to laminate a resin and an inorganic material.

[0354] Note that the configuration shown in this embodiment may be appropriately combined with other embodiments or other configurations in this embodiment. Combinations are possible.

[0355] (Embodiment 5) In this embodiment, a display module, an electronic device, a light-emitting element, and a display device each including a light-emitting element of one embodiment of the present invention will be described. The optical device and the lighting device will be described with reference to FIGS.

[0356] <Explanation about the display module> The display module 8000 shown in FIG. 11 includes an upper cover 8001 and a lower cover 8002. Between them, the touch sensor 8004 connected to FPC8003 and the touch sensor 8005 connected to FPC8006 are A display device 8006, a frame 8009, a printed circuit board 8010, and a battery 8011 are included. do.

[0357] The light-emitting element of one embodiment of the present invention can be used for the display device 8006, for example.

[0358] The upper cover 8001 and the lower cover 8002 are connected to the touch sensor 8004 and the display device 8005. The shape and dimensions can be changed appropriately to match the size of 006.

[0359] The touch sensor 8004 is a resistive or capacitive touch sensor mounted on the display device 8 8006. In addition, the display device 8006 can be used as an opposing substrate (sealing substrate). It is also possible to provide a touch sensor function. It is also possible to provide an optical sensor in each pixel to form an optical touch sensor.

[0360] The frame 8009 has a function of protecting the display device 8006 and also a function of preventing the operation of the printed circuit board 8010. It also functions as an electromagnetic shield to block electromagnetic waves generated by the frame. The frame 8009 may also function as a heat sink.

[0361] The printed circuit board 8010 includes a power supply circuit, a signal circuit for outputting a video signal and a clock signal. The power supply circuit is provided with a signal processing circuit. Alternatively, the power source may be a battery 8011 provided separately. This can be omitted if a commercial power source is used.

[0362] In addition, the display module 8000 includes components such as a polarizing plate, a retardation plate, and a prism sheet. It may also be provided in addition.

[0363] <Electronic device instructions> 12(A) to 12(G) are diagrams showing electronic devices. These electronic devices are housed in a housing. A body 9000, a display unit 9001, a speaker 9003, operation keys 9005 (power switch, includes an operation switch), a connection terminal 9006, a sensor 9007 (force, displacement, position, speed, Acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electricity Measures field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor or infrared 9008, etc. Also, the sensor 9 007 may have a function of measuring biological information such as a pulse sensor or a fingerprint sensor.

[0364] The electronic devices shown in FIGS. 12A to 12G can have various functions. For example, functions to display various information (still images, videos, text images, etc.) on the display, Sensor function, calendar, date or time display function, various software ( It has the function of controlling processing by using a program, wireless communication function, and various functions using wireless communication function. Functions for connecting to computer networks, transmitting various data using wireless communication functions, or receiving the program or data recorded on the recording medium, and It should be noted that the functions shown in FIGS. 12(A) to 12(G) can be implemented. The functions that the electronic device shown in the figure can have are not limited to these, and it may have various functions. Although not shown in FIGS. 12(A) to 12(G), the electronic device may include: The electronic device may have a plurality of display units. The function to take pictures, take videos, and save the images to a recording medium (external or built-in to the camera) ) and a function to display the captured image on the display unit.

[0365] The electronic devices shown in FIGS. 12A to 12G will be described in detail below.

[0366] FIG. 12A is a perspective view showing a mobile information terminal 9100. The display portion 9001 is flexible. The display unit 9001 can be incorporated along the screen. It is equipped with a touch panel, and can be operated by touching the screen with a finger or a stylus. By touching the icon displayed on the display 9001, the application can be started. can.

[0367] 12B is a perspective view showing a portable information terminal 9101. For example, the device has one or more functions selected from a telephone, a notebook, an information viewing device, etc. Specifically, it can be used as a smartphone. Although the speaker 9003, the connection terminal 9006, the sensor 9007, etc. are omitted in the illustration, It can be installed in the same position as the mobile information terminal 9100 shown in FIG. The information terminal 9101 can display text and image information on multiple surfaces. For example, Three operation buttons 9050 (also called operation icons or simply icons) are displayed on the display unit 900. 9051 shown in a dashed rectangle can be displayed on one side of the display unit 90. 01. An example of the information 9051 is an e-mail A display that notifies you of incoming calls, SNS (social networking services), etc. , subject of email or SNS, sender name of email or SNS, date and time, time, There are also displays showing the remaining battery level, the strength of the received signal, etc. Even if you display operation buttons 9050 instead of information 9051 at the displayed position, good.

[0368] The housing 9000 is made of a material such as alloy, plastic, or ceramic. Reinforced plastic can also be used as the plastic. Carbon Fiber Reinforced Resin Composite (CFRP), a type of carbon fiber composite Carbon fiber reinforced plastics (CFRP) have the advantage of being lightweight and corrosion-resistant. Other reinforced plastics include glass fiber reinforced plastics and aramid fiber reinforced plastics. Examples of alloys include aluminum alloys and Magnesium alloys include non-metallic alloys containing zirconium, copper, nickel, and titanium. Amorphous alloys (also called metallic glasses) have excellent elastic strength. It is an amorphous alloy that has a glass transition region at room temperature and is also called a bulk-solidifying amorphous alloy. It is an alloy having a substantially amorphous atomic structure. The alloy material is poured into the housing mold and solidified to form a part of the housing with bulk solidified amorphous alloy. Amorphous alloys include zirconium, copper, nickel, titanium, as well as beryllium and silicon. Cobalt, niobium, boron, gallium, molybdenum, tungsten, manganese, iron, cobalt The amorphous alloy may contain yttrium, vanadium, phosphorus, carbon, etc. Not limited to solid casting, but also vacuum deposition, sputtering, electrolytic plating, electroless plating, etc. The amorphous alloy may be formed by the above method. As long as the alloy maintains a state free of crystallites, it may contain microcrystals or nanocrystals. , both complete solid solution alloys with a single solid phase structure and partial solutions with two or more phases. The housing 9000 is made of an amorphous alloy, which gives it high elasticity. Therefore, even if the portable information terminal 9101 is dropped, the housing 9000 is made of an amorphous alloy. If the impact is applied, the mobile information terminal 910 will return to its original shape even if it is temporarily deformed at the moment of impact. 1 can improve the impact resistance.

[0369] 12C is a perspective view showing a portable information terminal 9102. The portable information terminal 9102 is , and has the function of displaying information on three or more surfaces of the display unit 9001. An example is shown in which information 9053 and information 9054 are displayed on different sides. The user of the portable information terminal 9102 stores the portable information terminal 9102 in the breast pocket of the clothes. In this state, the display (information 9053 in this case) can be confirmed. The telephone number or name of the caller is displayed in a position that can be observed from above the mobile information terminal 9102. The user can view the display without taking the mobile information terminal 9102 out of his pocket. You can check the call and decide whether to accept it or not.

[0370] 12(D) is a perspective view showing a wristwatch-type portable information terminal 9200. The 9200 is suitable for mobile phone calls, e-mail, document browsing and writing, music playback, and internet communications. It is possible to run various applications such as computer games. The display surface of the display unit 9001 is curved, and the display is performed along the curved display surface. In addition, the portable information terminal 9200 can perform short-distance wireless communication according to a communication standard. For example, by communicating with a wireless headset, The mobile information terminal 9200 also has a connection terminal 9006. It has a connector and can directly exchange data with other information terminals. Charging can also be performed via the connection terminal 9006. It may also be possible to supply power wirelessly without going through 6.

[0371] 12(E), (F), and (G) are perspective views showing a foldable portable information terminal 9201. 12(E) is a perspective view of the portable information terminal 9201 in an unfolded state, and FIG. (F) shows the mobile information terminal 9201 being changed from one of the unfolded state and the folded state to the other. 12(G) is a perspective view of the portable information terminal 9201 in a folded state. The portable information terminal 9201 is highly portable when folded, and is easily portable when unfolded. When the display is turned on, the seamless, wide display area provides excellent visibility of the display. The display unit 9001 of the display device 01 is made up of three housings 9000 connected by hinges 9055. The two housings 9000 are supported by the hinge 9055. This allows the portable information terminal 9201 to be reversibly transformed from an unfolded state to a folded state. For example, the portable information terminal 9201 can be bent with a radius of curvature of 1 mm or more and 150 mm or less. It can be done.

[0372] Furthermore, examples of electronic devices include television sets (televisions or television receivers) monitors for computers, digital cameras, digital video cameras, etc. Any camera, digital photo frame, or mobile phone (also called a mobile phone or mobile phone device) , goggle-type displays (head-mounted displays), portable game consoles, portable information Examples include terminals, audio playback devices, and large game machines such as pachinko machines.

[0373] Furthermore, the electronic device of one embodiment of the present invention may include a secondary battery and may perform contactless power transmission. It is preferable that the secondary battery can be charged using the power supply.

[0374] As the secondary battery, for example, a lithium polymer battery (lithium ion battery) using a gel electrolyte is used. Lithium-ion secondary batteries such as lithium-ion polymer batteries, lithium-ion batteries, nickel-metal hydride batteries batteries, nickel-cadmium batteries, organic radical batteries, lead-acid batteries, secondary air batteries, nickel-zinc batteries, silver-zinc batteries Examples include lead batteries.

[0375] The electronic device according to one embodiment of the present invention may include an antenna. By using the battery, it is possible to display images, information, etc. on the display unit. , the antenna may be used for contactless power transfer.

[0376] Furthermore, since the electronic device or lighting device of one embodiment of the present invention is flexible, it can be easily installed inside a house or a building. It can also be incorporated into walls or exterior walls, or along the curved surfaces of the interior or exterior of a vehicle. For example, installing lighting on the dashboard, windshield, ceiling, etc. of a car can This can be done.

[0377] <Explanation about the light-emitting device> FIG. 13(A) is a perspective view of a light emitting device 3000 according to this embodiment. The cross-sectional view corresponding to the dashed line EF is shown in FIG. 13(B). In A), some of the components are shown with dashed lines to avoid cluttering the drawing.

[0378] The light emitting device 3000 shown in FIGS. 13(A) and 13(B) includes a substrate 3001 and a light emitting layer on the substrate 3001. an optical element 3005, a first sealing region 3007 provided on the periphery of the light emitting element 3005, and a second sealing region 3007. and a second sealing region 3009 provided on the outer periphery of the first sealing region 3007.

[0379] The light emitted from the light emitting element 3005 is incident on either the substrate 3001 or the substrate 3003. In Fig. 13(A) and (B), light is emitted from the light emitting element 3005. A configuration in which light is emitted downward (toward the substrate 3001) will be described.

[0380] As shown in FIGS. 13A and 13B, the light emitting device 3000 includes a light emitting element 3005. A double sealing structure is arranged surrounded by a first sealing region 3007 and a second sealing region 3009. The double sealing structure prevents external impurities (e.g. However, the first sealing region 300 7 and the second sealing region 3009 are not necessarily provided. It may be configured with only 007.

[0381] In FIG. 13B, the first sealing region 3007 and the second sealing region 3009 are , and are provided in contact with the substrate 3001 and the substrate 3003. However, the present invention is not limited to this. For example, one or both of the first sealing region 3007 and the second sealing region 3009 may be formed on the substrate 30. The insulating film or conductive film formed above the insulating film 01 may be provided in contact with the insulating film or conductive film. Alternatively, one or both of the first sealing region 3007 and the second sealing region 3009 may be formed on the substrate. It may be configured to be in contact with the insulating film or conductive film formed below 3003. stomach.

[0382] The substrate 3001 and the substrate 3003 are the same as the substrate 200 described in the previous embodiment. The light emitting element 3005 may have the same structure as the substrate 220. The light-emitting element may have the same configuration as that described above.

[0383] The first sealing region 3007 is made of a material containing glass (for example, glass frit, glass The second sealing region 3009 may be made of a material containing resin. By using a material containing glass for the first sealing region 3007, In addition, the second sealing region 3009 can be made of a material containing a resin. By using this material, it is possible to improve the impact resistance and heat resistance. The first sealing region 3007 and the second sealing region 3009 are not limited to this. The first sealing region 3009 is formed of a material containing resin, and the second sealing region 3009 is formed of a material containing glass. Good too.

[0384] The glass frit may be, for example, magnesium oxide, calcium oxide, Strontium oxide, barium oxide, cesium oxide, sodium oxide, potassium oxide, acid Boron oxide, vanadium oxide, zinc oxide, tellurium oxide, aluminum oxide, silicon dioxide, acid Lead oxide, tin oxide, phosphorus oxide, ruthenium oxide, rhodium oxide, iron oxide, copper oxide, manganese dioxide ZnO, molybdenum oxide, niobium oxide, titanium oxide, tungsten oxide, bismuth oxide, Zirconium oxide, lithium oxide, antimony oxide, lead borate glass, tin phosphate glass , vanadate glass, or borosilicate glass. It is preferable that both contain one or more transition metals.

[0385] The glass frit may be formed by applying a frit paste to a substrate, for example. This is then subjected to heat treatment or laser irradiation. The resin is diluted with an organic solvent (also called a binder). It is also possible to use a laser beam having an absorbent added thereto that absorbs light of the wavelength of the laser beam. It is preferable to use, for example, an Nd:YAG laser or a semiconductor laser as the laser. Furthermore, the shape of the laser beam may be circular or rectangular.

[0386] Examples of materials containing the above-mentioned resins include polyester, polyolefin, and poly. Amide (nylon, aramid, etc.), polyimide, polycarbonate or acrylic resin, Polyurethane and epoxy resins can be used. Alternatively, siloxane such as silicone can be used. Materials containing resins with SAN bonds can be used.

[0387] In addition, either one or both of the first sealing region 3007 and the second sealing region 3009 When a material containing glass is used for the substrate 3001, the thermal expansion coefficient of the material containing glass and the substrate 3001 is By adopting the above-mentioned configuration, the material or substrate containing glass is prevented from being damaged by thermal stress. This can prevent cracks from occurring in the plate 3001.

[0388] For example, the first sealing region 3007 may be made of a material containing glass, and the second sealing region 3009 may be made of a material containing glass. When a material containing resin is used, the following excellent effects are obtained.

[0389] The second sealing region 3009 is closer to the periphery of the light emitting device 3000 than the first sealing region 3007. The light emitting device 3000 is provided on the side closer to the outer periphery. Therefore, the distortion becomes large on the outer peripheral side of the light emitting device 3000, that is, on the second The first sealing region 3009 is sealed with a material containing resin, and the second sealing region 3009 is sealed with a material containing resin. By sealing the first sealing region 3007 provided on the inside with a material containing glass, The light emitting device 3000 is less likely to break even if distortion due to external force or the like occurs.

[0390] As shown in FIG. 13(B), the substrate 3001, the substrate 3003, the first sealing region 30 A first region 3011 is formed in the region surrounded by the second sealing region 3007 and the second sealing region 3009. In addition, the substrate 3001, the substrate 3003, the light emitting element 3005, and the first sealing region 300 In the area surrounded by 7, a second area 3013 is formed.

[0391] The first region 3011 and the second region 3013 may be filled with, for example, a rare gas or a nitrogen gas. It is preferable that the container is filled with an inert gas such as acrylic or epoxy resin. It is preferable that the first region 3011 and the second region 3013 are filled with Preferably, the pressure is reduced below atmospheric pressure.

[0392] Also, a modified example of the configuration shown in Fig. 13(B) is shown in Fig. 13(C). FIG. 3 is a cross-sectional view showing a modified example of the device 3000.

[0393] In FIG. 13(C), a recess is provided in a part of the substrate 3003, and a desiccant 3018 is provided in the recess. The rest of the configuration is the same as that shown in FIG.

[0394] Desiccants 3018 are substances that adsorb moisture by chemical adsorption or by physical adsorption. Therefore, a substance that absorbs moisture can be used. For example, a desiccant 3018 can be used. The substances that can be used include oxides of alkali metals and oxides of alkaline earth metals (oxides calcium and barium oxide), sulfates, metal halides, perchlorates, zeolites, Examples include silica gel.

[0395] <Explanation about lighting equipment> FIG. 14 shows an example in which the light-emitting element is used as an indoor lighting device 8501. Since the surface area can be increased, a large-area lighting device can be formed. By using a housing having the above structure, a lighting device 8502 having a curved light-emitting area can be formed. The light-emitting element shown in this embodiment mode has a thin film shape, and the housing can be designed with a high degree of freedom. Therefore, it is possible to create lighting devices with various elaborate designs. A large lighting device 8503 may be provided on the wall. A touch sensor may be provided in 503 to turn the power on or off.

[0396] In addition, by using light-emitting elements on the surface of the table, it has the function of a table. The lighting device 8504 can be used as a lighting device. This allows the lighting device to function as furniture.

[0397] As described above, a display module, a light-emitting device, and a light-emitting element according to one embodiment of the present invention are used. The electronic device and the lighting device can be obtained. The applicable lighting device and the electronic device are as follows: The present invention is not limited to the present embodiment, but is applicable to lighting devices and electronic devices in all fields. It is possible.

[0398] The structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. You can be there. [Example]

[0399] Example 1 In this example, a manufacturing example of a light-emitting element according to one embodiment of the present invention and characteristics of the light-emitting element will be described. The structure of the light-emitting device fabricated in this example is the same as that shown in Figure 1. The details of the device structure are shown in Table 1. and Table 2. The structures and abbreviations of the compounds used are shown below.

[0400] [ka]

[0401] [ka]

[0402] [Table 1]

[0403] [Table 2]

[0404] <Fabrication of light-emitting devices> A method for manufacturing the light-emitting element manufactured in this example will be described below.

[0405] <Fabrication of Light-Emitting Device 1> An ITSO film was formed on a glass substrate as an electrode 101 to a thickness of 70 nm. The electrode area of ​​the electrode 101 is 4 mm 2 (2mm x 2mm).

[0406] Next, a hole injection layer 111 made of DBT3P-II and molybdenum oxide was formed on the electrode 101. (MoO3) and the weight ratio (DBT3P-II:MoO3) was 1:0.5. The co-evaporation was carried out so that the thickness became 20 nm.

[0407] Next, a hole transport layer 112 was formed on the hole injection layer 111 by depositing PCCP to a thickness of 20 nm. The vapor deposition was carried out so that

[0408] Next, a light-emitting layer 130 containing 4,6mCzP2Pm and PCCP was formed on the hole transport layer 112. and tris{2-[4-(4-cyano-2,6-diisobutylphenyl)-5-(2-methylphenyl)- (4H-1,2,4-triazol-3-yl)-κN 2 ]phenyl-κC } Iridium (III) (abbreviation: Ir(mpptz-diBuCNp)3) and (4,6mCzP2Pm:PCCP:Ir(mpptz-diBuCNp)3) is 0.4 : 0.6 : 0.125 and to a thickness of 30 nm, followed by co-evaporation. , weight ratio (4,6mCzP2Pm:PCCP:Ir(mpptz-diBuCNp)3) The ratio of the SiO2 to the total thickness was 0.8:0.2:0.125, and the thickness was 10 nm. In the light-emitting layer 130, Ir(mpptz-diBuCNp)3 was used as the guest material (first 1 organic compound), and 4,6mCzP2Pm is the host material (second organic compound). PCCP is the host material (third organic compound).

[0409] Next, on the light-emitting layer 130, 4,6mCzP2Pm was deposited to a thickness of 1 The deposition was carried out in sequence so that the thickness of BPhen was 10 nm and the thickness of BPhen was 15 nm. On the electron transport layer 118, LiF was evaporated to a thickness of 1 nm as the electron injection layer 119. I arrived.

[0410] Next, on the electron injection layer 119, aluminum (Al) was deposited to a thickness of 20 It was formed so that the thickness was 0 nm.

[0411] Next, in a glove box with a nitrogen atmosphere, a glass substrate for sealing is attached to an organic The EL sealant is used to fix the organic material to the glass substrate, forming a light-emitting element 1. Specifically, a sealant was applied to the periphery of the organic material formed on the glass substrate, and the The glass substrate and the glass substrate for sealing were bonded together, and ultraviolet light with a wavelength of 365 nm was applied for 6 hours. J / cm 2 The light-emitting element 1 was obtained by the above steps.

[0412] <Fabrication of light-emitting element 2> The light-emitting element 2 is the same as the light-emitting element 1 shown above, except that the light-emitting layer 130 and the electron transport layer 118 are formed in the same manner. The only difference was the manufacturing method of the light-emitting element 1, except for the above.

[0413] The light-emitting layer 130 of the light-emitting element 2 is made of 2,4,6-tris[3-(9H-carbazole- 9-yl)phenyl]pyrimidine (abbreviation: mCzP3Pm), PCCP, and Ir(mp ptz-diBuCNp)3 and the weight ratio (mCzP3Pm:PCCP:Ir(mppt z-diBuCNp)3) is 0.2:0.8:0.06, and the thickness is 20n m, and then co-evaporated in a weight ratio of (mCzP3Pm:PCCP:Ir(mppt z-diBuCNp)3) is 0.6:0.4:0.06, and the thickness is 20n In the light-emitting layer 130, Ir(mpptz-diBuCNp )3 is a guest material (first organic compound), and mCzP3Pm is a host material (second organic compound). The first organic compound is the ZnO-based polymer, and the second organic compound is the host material (third organic compound).

[0414] Next, mCzP3Pm was deposited on the light-emitting layer 130 to a thickness of 10 nm as the electron transport layer 118. The layers were evaporated in this order so that the thickness of BPhen was 15 nm.

[0415] <Fabrication of Light-Emitting Element 3> The light-emitting element 3 is the same as the light-emitting element 1 shown above, except that the steps of forming the hole transport layer 112 and the light-emitting layer 130 are the same. The only difference was the manufacturing method of the light-emitting element 1, except for the above.

[0416] The hole transport layer 112 of the light-emitting element 3 is made of 4,4'-bis(9-carbazole)-2,2 '-Dimethylbiphenyl (abbreviation: dmCBP) was evaporated to a thickness of 20 nm.

[0417] Next, on the hole transport layer 112, a light emitting layer 130 containing 4,6mCzP2Pm and 12-[ 3-(9H-carbazol-9-yl)phenyl]-5,12-dihydro-5-phenyl- Indolo[3,2-a]carbazole (abbreviation: mCzPICz) and tris[3-methyl -1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazolato]yl Ir(Mptz1-mp)3) and 4.6mCzP 2Pm:mCzPICz:Ir(Mptz1-mp)3) is 0.6:0.4:0.125 and a thickness of 30 nm, followed by co-evaporation of 4.6 mC zP2Pm:mCzPICz:Ir(Mptz1-mp)3) is 0.8:0.2:0.1 The luminescent layer 130 was co-deposited to a thickness of 10 nm. , Ir(Mptz1-mp)3 is the guest material (first organic compound), and 4,6mCz P2Pm is the host material (second organic compound), and mCzPICz is the host material (third organic compound). (an organic compound).

[0418] <Fabrication of Light-Emitting Element 4> The light-emitting element 4 is the same as the light-emitting element 1 described above, except that it has a hole injection layer 111, a light-emitting layer 130, and an electron transport layer. The only difference was the process of forming the light-emitting layer 118, and the other processes were the same as those of the light-emitting element 1. .

[0419] The hole injection layer 111 of the light-emitting element 4 was formed by mixing DBT3P-II and MoO3 in a weight ratio of ( The ratio of DBT3P-II:MoO3 was 1:0.5 and the thickness was 25 nm. The resulting mixture was co-evaporated with the aluminum alloy.

[0420] Furthermore, on the hole transport layer 112, a light emitting layer 130 was formed by dissolving 9,9'-[pyrimidine-4,6- Diylbis(biphenyl-3,3'-diyl)]bis(9H-carbazole) (abbreviation: 4 ,6mCzBP2Pm), PCCP, and tris{2-[5-(2-methylphenyl)- 4-(2,6-diisopropylphenyl)-4H-1,2,4-triazol-3-yl -κN 2 ]phenyl-κC}iridium(III) (abbreviation: Ir(mpptz-diPr p)3) and the weight ratio (4,6mCzBP2Pm:PCCP:Ir(mpptz-diP rp)3) to be 0.4:0.6:0.125 and the thickness to be 30 nm. and then co-evaporated with a weight ratio of (4.6mCzBP2Pm:PCCP:Ir(mpptz- The ratio of diPrp)3) was 0.8:0.2:0.125 and the thickness was 10 nm. In the light-emitting layer 130, Ir(mpptz-diPrp)3 was co-deposited. The first organic compound is the substrate material, and the second organic compound is the host material. compound) and PCCP is the host material (third organic compound).

[0421] Next, a 1000-membrane thin film of 4,6mCzBP2Pm was deposited on the light-emitting layer 130 as the electron transport layer 118. The layers were evaporated sequentially to a thickness of 0 nm, and then to a thickness of 15 nm for BPhen.

[0422] <Fabrication of Light-Emitting Elements 5 to 7> The light-emitting elements 5 to 7 differ from the light-emitting element 1 described above only in the process of forming the light-emitting layer 130. The other steps were the same as those for the light-emitting element 1.

[0423] The light-emitting layer 130 of the light-emitting element 5 is made of 4,6mCzP2Pm, PCCP, and Ir(mp PtZ-diPrp)3 and the weight ratio (4.6mCzP2Pm:PCCP:Ir(mpp The ratio of tz-diPrp)3) is 0.2:0.8:0.125, and the thickness is 30 mm. m, followed by co-evaporation in a weight ratio of (4.6mCzP2Pm:PCCP:Ir (m The ratio of pptz-diPrp)3) is 0.8:0.2:0.125, and the thickness is 1 In the light-emitting layer 130, Ir(mpptz-diPrp ) 3 is a guest material (first organic compound), and 4,6mCzP2Pm is a host material (second organic compound). The second organic compound is the ZnO-based polymer (PCCP), and the third organic compound is the host material.

[0424] The light-emitting layer 130 of the light-emitting element 6 is made of a mixture of 4,6mCzP2Pm, PCCP, and tris{2 -[1-(4-cyano-2,6-diisobutylphenyl)-1H-imidazol-2-yl] {Ir(pim-diBuC} Np)3) and a weight ratio of (4,6mCzP2Pm:PCCP:Ir(pim-diBuC Np)3) is 0.2:0.8:0.125 and the thickness is 30 nm. and then co-evaporated with 4.6mCzP2Pm:PCCP:Ir(pim-diB uCNp)3) is 0.6:0.4:0.125 and the thickness is 10 nm In the light-emitting layer 130, Ir(pim-diBuCNp)3 was used as a guest material (first organic compound), and 4,6mCzP2Pm is the host material (second organic compound). The ZnO-based polymer is a ZnO-based material (a third organic compound), and PCCP is the host material (a third organic compound).

[0425] The light-emitting layer 130 of the light-emitting element 7 is made of a mixture of 4,6mCzP2Pm, PCCP, and tris{2 -[1-(2,6-diisopropylphenyl)-1H-imidazol-2-yl-κN 3 ]phenyl-κC}iridium(III) (abbreviation: Ir(iPrpim)3) and The ratio (4,6mCzP2Pm:PCCP:Ir(iPrpim)3) was 0.2:0.8:0 The mixture was co-evaporated to a weight ratio of 4.125 and a thickness of 30 nm. ,6mCzP2Pm:PCCP:Ir(iPrpim)3) is 0.8:0.2:0.12 The emitting layer 130 was formed by co-evaporation so that the thickness of the emitting layer 130 was 10 nm. Ir(iPrpim)3 is the guest material (first organic compound), and 4,6mCzP2P m is a host material (second organic compound), and PCCP is a host material (third organic compound). )

[0426] <Light-emitting element characteristics> Next, the characteristics of the fabricated light-emitting elements 1 to 7 were measured. The intensity was measured using a color luminance meter (Topcon, BM-5A), and the electroluminescence spectrum was measured. A multichannel spectrometer (PMA-11, manufactured by Hamamatsu Photonics) was used for the measurement.

[0427] 15A and 15B show the luminance-current density characteristics of the light-emitting elements 1 to 7, and the luminance-voltage characteristics of the light-emitting elements 1 to 7. The characteristics are shown in Figures 16(A) and 16(B), the current efficiency-luminance characteristics are shown in Figures 17(A) and 17(B), and the external quantum efficiency The efficiency-luminance characteristics of the light-emitting elements 1 to 7 are shown in FIGS. and 2.5mA / cm 2 The electroluminescence spectrum when a current is passed at a current density of The measurements of each light-emitting element were carried out at room temperature (an atmosphere maintained at 23°C). went.

[0428] Also, 1000cd / m 2 The element characteristics of the light-emitting elements 1 to 7 in the vicinity are shown in Table 3. Shown below.

[0429] [Table 3]

[0430] The electroluminescence spectra of the light-emitting elements 1 to 7 have peak wavelengths on the shortest wavelength side. 489nm, 485nm, 473nm, 478nm, 477nm, 498nm, 4 The emission wavelength was 72 nm, with a peak in the blue region. The light emission originates from the material. The full widths are 66nm, 64nm, 70nm, 71nm, 75nm, 70nm, and 1 The electroluminescence spectra of the light-emitting elements 3 to 7 were 37 nm, and the electroluminescence spectra of the light-emitting elements 1 and 2 were 37 nm. It showed a spectral shape wider than that of the optical element 2. In particular, the electroluminescence spectrum of the light-emitting element 7 had a wide spectral shape and showed broad emission in the wavelength region from green to yellow, along with the emission derived from the guest material Ir(iPrpim)3.

[0431] Also, the emission start voltages (voltages exceeding a luminance of 1 cd / m 2 ) of the light-emitting elements 1 to 7 were 2.5 V, 2.5 V, 2.7 V, 2.5 V, 2.4 V, 2.7 V, and 2.5 V respectively. As will be shown later, this voltage value is smaller than the voltage corresponding to the energy difference between the LUMO level and the HOMO level of the guest material possessed by each light-emitting element. Therefore, in the light-emitting elements 1 to 7, it is suggested that carriers are recombining not directly in the guest material, but in a material having a smaller energy gap.

[0432] Also, the driving voltages of the light-emitting elements 1 to 4 in the high luminance region are lower than those of the light-emitting elements 5 to 6. Also, the light-emitting elements 1 and 2 showed high power efficiency because they had low driving voltages and high current efficiency.

[0433] Also, the maximum values of the external quantum efficiencies of the light-emitting elements 1 to 7 were 33.8%, 3 1.9%, 30.3%, 29.1%, 20.0%, 24.7%, and 10.3% respectively, and the light-emitting elements 1 to 4 showed high values exceeding 25%. L>

[0434] <CV measurement results> Next, the electrochemical characteristics (oxidation reaction characteristics and reduction reaction characteristics) of the compounds used in the above light-emitting elements were measured by cyclic voltammetry (CV) measurement. For the measurement, an electric ... Chemical analyzer (manufactured by BAS Co., Ltd., model number: ALS model 600A or 60 The potential of the working electrode relative to the reference electrode was varied within an appropriate range. The oxidation and reduction peak potentials were obtained. The peak voltage is estimated to be -4.94 eV, so this value and the obtained peak voltage From the positions, the HOMO and LUMO levels of each compound were calculated.

[0435] The host material (the second organic compound and the third organic compound) is 4,6mCzP2Pm. , mCzP3Pm, 4,6mCzBP2Pm, PCCP, and mCzPICz Each compound was dissolved in N,N-dimethylformamide (DMF) The oxidation and reduction reaction characteristics were measured. Since the dielectric constant of organic compounds is about 3, DMF (with a dielectric constant of 38 ) to form relatively polar iridium complexes (especially electron-withdrawing iridium complexes), such as fac-type iridium complexes. Measurement of the oxidation properties of compounds (with highly reactive substituents) can be inaccurate. Therefore, in this example, the guest material (first organic compound) Ir(mp ptz-diBuCNp)3, Ir(Mptz1-mp)3, Ir(mpptz-diP rp)3, Ir(pim-diBuCNp)3, and Ir(iPrpim)3 The acid was measured using a solution of each compound dissolved in chloroform (dielectric constant: 4.8) with low polarity. The reduction reaction characteristics of the guest materials were measured by dissolving each compound in DMF. The measurement was carried out using the solution.

[0436] The oxidation and reduction potentials of each compound obtained from the CV measurement, and the results of the CV measurement The HOMO level and LUMO level of each compound calculated by the above are shown in Table 4. The reduction potential of iPrpim)3 was low and no clear reduction peak potential was observed. , Ir(iPrpim)3 is expected to have a high LUMO level.

[0437] [Table 4]

[0438] As shown in Table 4, the first organic compound (Ir(mpptz-diBu)) CNp)3, Ir(Mptz1-mp)3, Ir(mpptz-diPrp)3, Ir( The HOMO levels of Ir(iPrpim)3 and Ir(iBuCNp)3 are The second organic compound (4,6mCzP2Pm, mCzP3Pm, and 4,6mC The first organic compound (Ir(mpptz-di)) is BuCNp)3, Ir(Mptz1-mp)3, Ir(mpptz-diPrp)3, I The LUMO levels of Ir(pim-diBuCNp)3 and Ir(iPrpim)3 are Two organic compounds (4,6mCzP2Pm, mCzP3Pm, and 4,6mCzBP2Pm) ) or higher. When this compound is used, electrons and holes, which are carriers injected from a pair of electrodes, Efficiently convert the second organic compound (host material) and the first organic compound (guest material) into The second organic compound (host material) and the first organic compound (guest material) are injected. is a combination that can form an exciplex.

[0439] In this case, the first organic compound (Ir(mpttz-diBuCNp), Ir(Mpt z1-mp)3, Ir(mpptz-diPrp)3, Ir(pim-diBuCNp) 3, and Ir(iPrpim)3) and a second organic compound (4,6mCzP2Pm, mCz The exciplex formed with P3Pm and 4,6mCzBP2Pm is converted to a second organic compound. The first organic compound becomes an exciplex having a LUMO level and a HOMO level.

[0440] <Emission spectrum of thin film 1> Here, the first organic compound (guest material) and the second organic compound (guest material) used in the light-emitting elements 1 to 7 are A thin film sample containing an organic compound (host material) was prepared, and the emission spectrum of the thin film was measured. For comparison, we also measured the LUMO level of 35DCzPPy A comparative thin film sample having a first organic compound (guest material) and a second organic compound (guest material) was also prepared.

[0441] Thin film 1 was prepared by depositing 4,6mCzP2Pm and Ir(mpptz-diBuC Np)3 and a weight ratio of (4,6mCzP2Pm:Ir(mpptz-diBuCNp)3 ) was co-deposited to a thickness of 50 nm. That is, the thin film 1 is a thin film containing the compound used in the light-emitting layer 130 of the light-emitting element 1 .

[0442] Thin film 2 was prepared by depositing mCzP3Pm and Ir(mpptz-diBuCNp) on a quartz substrate. 3, the weight ratio (mCzP3Pm:Ir(mPpTz-diBuCNp)3) is 1:0. The thin film 2 was co-deposited to a thickness of 50 nm. , a thin film containing the compound used in the light-emitting layer 130 of the light-emitting element 2.

[0443] Comparative thin film 1 was prepared by depositing 35DCzPPy and Ir(mpptz-diBuC Np)3 and the weight ratio (35DCzPPy:Ir(mpptz-diBuCNp)3) They were co-deposited at a ratio of 1:0.125 to a thickness of 50 nm.

[0444] Thin film 3 was prepared by depositing 4,6mCzP2Pm and Ir(Mptz1-mp)3 on a quartz substrate. The weight ratio (4,6mCzP2Pm:Ir(Mptz1-mp)3) was 1:0.125 The thin film 3 was co-deposited so as to have a thickness of 50 nm. It is a thin film containing the compound used in the light-emitting layer 130 of the element 3.

[0445] Comparative thin film 2 was prepared by depositing 35DCzPPy and Ir(Mptz1-mp)3 on a quartz substrate. The weight ratio (35DCzPPy:Ir(Mptz1-mp)3) is 1:0.125 The co-evaporation was carried out so that the thickness of the layer was 50 nm.

[0446] Thin film 4 was prepared by depositing 4,6mCzBP2Pm and Ir(mpptz-diPr p)3 and the weight ratio (4,6mCzBP2Pm:Ir(mpptz-diPrp)3) The mixture was co-deposited at a ratio of 1:0.125 to a thickness of 50 nm. The thin film 4 is a thin film containing the compound used in the light-emitting layer 130 of the light-emitting element 4.

[0447] As the thin film 5, 4,6mCzP2Pm and Ir(mpptz-diPrp )3, and the weight ratio (4,6mCzP2Pm:Ir(mpptz-diPrp)3) is 1: The thin film was co-deposited so that the thickness of the thin film was 0.125 and the thickness was 50 nm. 5 is a thin film containing the compound used in the light-emitting layer 130 of the light-emitting element 5.

[0448] Comparative thin film 3 was prepared by depositing 35DCzPPy and Ir(mpptz-diPrp) on a quartz substrate. )3, and the weight ratio (35DCzPPy:Ir(mpptz-diPrp)3) was 1:0. The film was co-evaporated to a thickness of 50 nm and a thickness of 125 nm.

[0449] Thin film 6 was prepared by depositing 4,6mCzP2Pm and Ir(pim-diBuCNp )3 and the weight ratio (4,6mCzP2Pm:Ir(pim-diBuCNp)3) was 1: The thin film was co-deposited so that the thickness of the thin film was 0.125 and the thickness was 50 nm. 6 is a thin film containing the compound used in the light-emitting layer 130 of the light-emitting element 6.

[0450] Comparative thin film 4 was prepared by depositing 35DCzPPy and Ir(pim-diBuCNp )3 and the weight ratio (35DCzPPy:Ir(pim-diBuCNp)3) was 1:0. The film was co-evaporated to a thickness of 50 nm and a thickness of 125 nm.

[0451] As the thin film 7, 4,6mCzP2Pm and Ir(iPrpim)3 were deposited on a quartz substrate. The weight ratio (4,6mCzP2Pm:Ir(iPrpim)3) was 1:0.125. That is, the thin film 7 was formed by co-evaporation so as to have a thickness of 50 nm. The optical layer 130 is a thin film having the compound used.

[0452] Comparative thin film 5 was prepared by depositing 35DCzPPy and Ir(iPrpim)3 on a quartz substrate. The weight ratio (35DCzPPy:Ir(iPrpim)3) was 1:0.125. The co-deposition was carried out so that the thickness became 50 nm.

[0453] The emission spectra of the prepared thin films 1 to 7 and comparative thin films 1 to 5 were measured. The emission spectrum was measured using an absolute quantum yield measurement device (Hamamatsu Photonics, C99 The wavelength of the excitation light was 250 nm. The measurements were carried out at room temperature (23°C). The measurement results are shown in Figures 20 to 26.

[0454] The LUMO and HOMO levels of 35DCzPPy were determined by the same method as described above. The LUMO level was measured at -2.39 eV and the HOMO level was measured at -5.90 e V. From this, it can be seen that the LUMO level of 35DCzPPy is the same as that of the first organic compound (I r(mpptz-diBuCNp)3, Ir(Mptz1-mp)3, Ir(mpptz -diPrp), Ir(pim-diBuCNp), and Ir(iPrpim). The LUMO level of 35DCzPPy and the first organic compound (Ir(mp ptz-diBuCNp)3, Ir(Mptz1-mp)3, Ir(mpptz-diP rp), Ir(pim-diBuCNp), and Ir(iPrpim) It can be said that this combination makes it difficult to form a complex. The emission of 5 is due to the exciplex formed between 35DCzPPy and the first organic compound. It can be said that the light emitted does not include the first organic compound, but includes light emitted from the first organic compound.

[0455] When the emission spectrum was measured, as shown in Fig. 20(A) and Fig. 21(A), Thin film 1 emits blue light from the phosphorescent compound Ir(mpptz-diBuCNp)3. On the other hand, the emission spectra of Thin Film 1 and Thin Film 2 were observed to be The emission spectrum was observed to be slightly shifted to longer wavelengths than that of 1.

[0456] Therefore, the emission spectrum of comparative thin film 1 was calculated from the emission spectra of thin films 1 and 2. The results of calculating the difference spectra after subtracting the two are shown in Figures 20(B) and 21(B). As a result, the luminescence of thin films 1 and 2 was attributed to Ir(mpptz-diBuCNp)3. In addition to the 487 nm peak wavelength, there are also 486 nm and 494 nm peaks, respectively. The difference scans for the emission spectra of thin films 1 and 2 were also Spectra (thin film 1 - comparative thin film 1 spectrum, and thin film 2 - comparative thin film 1 spectrum) The proportions (area ratios) were calculated to be 10.1% and 34.0%, respectively.

[0457] From the results of CV measurement, Ir(mpptz-diBuCNp)3 (first organic compound) and 4,6mCzP2Pm (second organic compound) is a combination that forms an exciplex. In addition, the LUMO levels of 4,6mCzP2Pm and Ir(mpptz-diBuCNp)3 The energy difference with the HOMO level is 2.52 eV. The emission energy (2.B) calculated from the peak wavelength of the difference spectrum of thin film 1 55 eV). Therefore, the emission spectrum observed in thin film 1 is In addition to the emission from the first organic compound, the light emitted from the second organic compound is It can be said that the emission originates from the exciplex.

[0458] The electroluminescence spectrum of the light-emitting element 1 shown in FIG. 19(A) is This shows that the emission spectrum of the thin film 1 is almost the same as that of the thin film 1. The emission spectrum was obtained by measuring the first organic compound (Ir(mpptz-diBuCNp)3) and The emission from the exciplex formed with the organic compound 2 (4,6mCzP2Pm) and the Ir( It can be said that the spectrum has emission originating from (mpptz-diBuCNp)3. In addition, since the difference between the S1 level and the T1 level of the exciplex is small, the energy of the luminescence exhibited by the exciplex is The energy is taken to be the energy of the S1 and T1 levels of the exciplex (2.55 eV). can be done.

[0459] In addition, the LUMO levels of 4,6mCzP2Pm and Ir(mpptz-diBuCNp)3 The energy difference (2.52 eV) between the HOMO level of Ir(mpptz-diBuCN p) The energy difference between the LUMO level and the HOMO level of 3 is smaller than that (2.92 eV). Therefore, the carriers are directly transported in the first organic compound (Ir(mpptz-diBuCNp)3). Without recombination, the first organic compound (Ir(mpptz-diBuCNp)3) and The carriers are recombined by the exciplex formed in the second organic compound (4,6mCzP2Pm). Since it is possible to combine the light emitting elements, the driving voltage of the light emitting element can be reduced.

[0460] In addition, the results of CV measurements showed that Ir(mpptz-diBuCNp)3 (the first organic compound) The compound (mCzP3Pm) and the second organic compound (mCzP3Pm) form an exciplex. In addition, the LUMO level of mCzP3Pm and the HOM of Ir(mpptz-diBuCNp)3 The energy difference with the O level is 2.49 eV. This energy difference is shown in Figure 21(B). The luminescence energy (2.51 e) calculated from the peak wavelength of the difference spectrum of thin film 2 shown Therefore, the emission spectrum observed in thin film 2 is consistent with that of the first organic In addition to the emission from the compound, the excitation light generated by the first organic compound and the second organic compound It can be said that the luminescence originates from the complex.

[0461] The electroluminescence spectrum of the light-emitting element 2 shown in FIG. 19(A) is This shows that the emission spectrum of the thin film 2 is roughly consistent with that of the thin film 2. The emission spectrum was obtained by measuring the first organic compound (Ir(mpptz-diBuCNp)3) and The emission from the exciplex formed with the organic compound (mCzP3Pm) of 2 and the Ir (mpp It can be said that the spectrum has emission originating from tz-diBuCNp. Since the difference between the S1 level and the T1 level of an exciplex is small, the energy of the luminescence emitted by the exciplex is can be considered as the energy of the S1 and T1 levels (2.51 eV) of the exciplex. do.

[0462] In addition, the LUMO level of mCzP3Pm and the HO of Ir(mpptz-diBuCNp)3 The energy difference (2.49 eV) with the MO level is Ir(mpptz-diBuCNp)3 The energy difference between the LUMO level and the HOMO level of , carriers directly recombine in the first organic compound (Ir(mpptz-diBuCNp)3) Without further elaboration, the first organic compound (Ir(mpptz-diBuCNp)3) and the second organic compound (Ir(mpptz-diBuCNp)3) were Carriers are recombined by exciplexes formed in organic compounds (mCzP3Pm). This allows the driving voltage of the light emitting element to be reduced.

[0463] Furthermore, as shown in FIG. 22(A), the comparative thin film 2 contains a phosphorescent compound, Ir(Mp The blue emission spectrum of thin film 3 was observed. The emission spectrum of the comparative thin film 2 is shifted to the longer wavelength side. was observed.

[0464] Therefore, the difference obtained by subtracting the emission spectrum of comparative thin film 2 from the emission spectrum of thin film 3 is The calculated spectrum is shown in FIG. 22(B). As a result, the thin film 3 was found to be composed of Ir(Mptz In addition to the emission with a peak wavelength of 470 nm derived from 1-mp3, The difference spectrum of the emission spectrum of thin film 3 was The ratio (area ratio) of the spectrum of thin film 3 to that of comparative thin film 2 was calculated to be 22.9%.

[0465] From the results of CV measurement, Ir(Mptz1-mp)3 (the first organic compound) and 4,6mC zP2Pm (second organic compound) is a combination that forms an exciplex. The energy difference between the LUMO level of 6mCzP2Pm and the HOMO level of Ir(Mptz1-mp)3 The energy difference is 2.66 eV. This roughly matches the emission energy (2.49 eV) calculated from the peak wavelength of the difference spectrum. Therefore, the emission spectrum observed in the thin film 3 is due to the first organic compound. In addition to the emission from the first organic compound, the second organic compound emits light from an exciplex formed between the first and second organic compounds. It can be said that luminescence is included.

[0466] The electroluminescence spectrum of the light-emitting element 3 shown in FIG. 19(A) is This shows that the emission spectrum of the thin film 3 is roughly consistent with that of the thin film 3. The emission spectra were obtained by comparing the first organic compound (Ir(Mptz1-mp)3) and the second organic compound (Ir(Mptz1-mp)3). The emission from the exciplex formed with the compound (4,6mCzP2Pm) and the emission from the Ir (Mptz1 The exciplex has a spectrum with emission originating from S Since the difference between the T1 and T2 levels is small, the luminescence energy of the exciplex is It can be considered as the energy of the S1 and T1 levels (2.49 eV).

[0467] In addition, the LUMO level of 4,6mCzP2Pm and the HOMO of Ir(Mptz1-mp)3 The energy difference (2.66 eV) between the LUMO level of Ir(Mptz1-mp)3 The energy difference between the HOMO level and the HOMO level is smaller than that (3.36 eV). In the compound (Ir(Mptz1-mp)3), carriers are not directly recombined, but are transferred to the first organic Compound (Ir(Mptz1-mp)3) and a second organic compound (4,6mCzP2Pm) The exciplex formed by the ionization reaction allows carriers to be recombined, and thus the driving force of the light-emitting element can be The dynamic voltage can be reduced.

[0468] As shown in FIGS. 23A and 24A, the comparative thin film 3 contains a phosphorescent compound The blue emission spectrum of Ir(mpptz-diPrp)3 was observed. On the other hand, the emission spectra of the thin films 4 and 5 have a peak on the long wavelength side. was observed.

[0469] Therefore, the emission spectrum of comparative thin film 3 was calculated from the emission spectra of thin films 4 and 5. The results of calculating the difference spectra after subtracting the two are shown in Figures 23(B) and 24(B). As a result, the luminescence of thin films 4 and 5 originates from Ir(mpptz-diPrp)3. In addition to the 475 nm peak wavelength, the peak wavelengths are 519 nm and 539 nm, respectively. In addition, the difference spectra for the emission spectra of thin films 4 and 5 were Spectra (thin film 4 - comparative thin film 3 spectrum, and thin film 5 - comparative thin film 3 spectrum) The area ratios were calculated to be 38.1% and 81.5%, respectively.

[0470] From the results of CV measurements, Ir(mpptz-diPrp)3 (the first organic compound) and 4, 6mCzBP2Pm (second organic compound) is a combination that forms an exciplex. In addition, the LUMO level of 4,6mCzBP2Pm and the HO of Ir(mpptz-diPrp)3 The energy difference with the MO level is 2.44 eV. This energy difference is shown in Figure 23(B). The emission energy (2.39 Therefore, the emission spectrum observed in thin film 4 is consistent with the first active In addition to the emission from the organic compound, the excitation light generated by the first organic compound and the second organic compound It can be said that the luminescence originates from the catalytic complex.

[0471] The electroluminescence spectrum of the light-emitting element 4 shown in FIG. 19(A) is This shows that the emission spectrum of the thin film 4 is roughly consistent with that of the thin film 4. The emission spectra were obtained by comparing the first organic compound (Ir(mpptz-diPrp)3) and the second organic compound (Ir(mpptz-diPrp)3). The emission from the exciplex formed with the organic compound (4,6mCzBP2Pm) and the Ir(m It can be said that the spectrum has the emission originating from pptz-diPrp3. Since the difference between the S1 level and the T1 level of an exciplex is small, the energy of the luminescence emitted by the exciplex is can be considered as the energy of the S1 and T1 levels of the exciplex (2.39 eV). do.

[0472] In addition, the LUMO levels of 4,6mCzBP2Pm and Ir(mpptz-diPrp)3 The energy difference (2.44 eV) from the HOMO level is Ir(mpptz-diPrp)3 The energy difference between the LUMO level and the HOMO level of , carriers recombine directly in the first organic compound (Ir(mpptz-diPrp)3) Without further ado, the first organic compound (Ir(mpptz-diPrp)3) and the second organic compound It is known that carrier recombination occurs through the exciplex formed in the compound (4,6mCzBP2Pm). This allows the driving voltage of the light emitting element to be reduced.

[0473] In addition, the results of CV measurement showed that Ir(mpptz-diPrp)3 (first organic compound) and 4,6mCzP2Pm (the second organic compound) form an exciplex. In addition, the LUMO level of 4,6mCzP2Pm and the H of Ir(mpptz-diPrp)3 The energy difference with the OMO level is 2.36 eV. This energy difference is shown in Figure 24(B The emission energy (2.3) calculated from the peak wavelength of the difference spectrum of the thin film 5 shown in Therefore, the emission spectrum observed in the thin film 5 is roughly consistent with the first In addition to the light emission originating from the organic compound, the light emitted from the first organic compound and the second organic compound It can be said that the emission originates from exciplexes.

[0474] The electroluminescence spectrum of the light-emitting element 5 shown in FIG. 19(B) is This shows that the emission spectrum of the thin film 5 is roughly consistent with that of the thin film 5. The emission spectra were obtained by comparing the first organic compound (Ir(mpptz-diPrp)3) and the second organic compound (Ir(mpptz-diPrp)3). The emission from the exciplex formed with the organic compound (4,6mCzP2Pm) and the Ir(mp It can be said that the spectrum has the emission originating from the excitation Since the difference between the S1 and T1 levels of the exciplex is small, the luminescence energy of the exciplex is can be considered as the energy of the S1 and T1 levels (2.30 eV) of the exciplex. .

[0475] In addition, the LUMO level of 4,6mCzP2Pm and the H The energy difference (2.36 eV) between the OMO level and the Ir(mpptz-diPrp) It is smaller than the energy difference between the LUMO level and the HOMO level (3.28 eV). The first organic compound (Ir(mpptz-diPrp)3) undergoes direct recombination of carriers. The first organic compound (Ir(mpptz-diPrp)3) and the second organic compound Carriers can be recombined by exciplexes formed in (4,6mCzP2Pm) Therefore, the driving voltage of the light emitting element can be reduced.

[0476] Furthermore, as shown in FIG. 25(A), the comparative thin film 4 contains a phosphorescent compound, Ir(pi The blue emission spectrum of m-diBuCNp3 was observed. The optical spectrum is shifted to the longer wavelength side compared to the emission spectrum of comparative thin film 4. Tor was observed.

[0477] Therefore, the difference obtained by subtracting the emission spectrum of comparative thin film 4 from the emission spectrum of thin film 6 is The calculated spectrum is shown in FIG. 25(B). As a result, the thi...

Claims

1. A light-emitting layer is disposed between a pair of electrodes, the light-emitting layer includes a first organic compound and a second organic compound; one of the first organic compound and the second organic compound has a LUMO level that is equal to or higher than a LUMO level of the other of the first organic compound and the second organic compound, and has a HOMO level that is equal to or higher than a HOMO level of the other of the first organic compound and the second organic compound; the first organic compound and the second organic compound are a combination that forms an exciplex, the first organic compound has a function of converting triplet excitation energy into luminescence, The luminescence energy of the first organic compound is E Ｇ＿ｅｍ and the emission energy of the exciplex is E Ｅｘ＿ｅｍ The transition energy calculated from the absorption edge of the absorption spectrum of the first organic compound is defined as E Ｇ＿ａｂｓ and the energy difference between the HOMO level of one of the first organic compound and the second organic compound and the LUMO level of the other of the first organic compound and the second organic compound is ΔE Ｅｘ When 0eV<E Ｇ＿ｅｍ -E Ｅｘ＿ｅｍ ≦0.23%V 0eV<E Ｇ＿ａｂｓ -E Ｅｘ＿ｅｍ ≦0.30%V 0eV<E Ｇ＿ａｂｓ -ΔE Ｅｘ ≦0.23eV A light-emitting element that satisfies the following relational expression.

2. A light-emitting layer is disposed between a pair of electrodes, the light-emitting layer includes a first organic compound and a second organic compound; one of the first organic compound and the second organic compound has a LUMO level that is equal to or higher than a LUMO level of the other of the first organic compound and the second organic compound, and has a HOMO level that is equal to or higher than a HOMO level of the other of the first organic compound and the second organic compound; the first organic compound and the second organic compound are a combination that forms an exciplex, the first organic compound has a function of converting triplet excitation energy into luminescence, The luminescence energy of the first organic compound is E Ｇ＿ｅｍ and the emission energy of the exciplex is E Ｅｘ＿ｅｍ The transition energy calculated from the absorption edge of the absorption spectrum of the first organic compound is defined as E Ｇ＿ａｂｓ and the energy difference between the HOMO level of one of the first organic compound and the second organic compound and the LUMO level of the other of the first organic compound and the second organic compound is ΔE Ｅｘ When 0eV<E Ｇ＿ｅｍ - E Ｅｘ＿ｅｍ ≦0.18eV 0eV<E Ｇ＿ａｂｓ -E Ｅｘ＿ｅｍ ≦0.25%V 0eV<E Ｇ＿ａｂｓ -ΔE Ｅｘ ≦0.18eV A light-emitting element that satisfies the following relational expression.

3. In claim 1 or claim 2, the luminescence energy E of the first organic compound Ｇ＿ｅｍ and the emission energy E of the exciplex Ｅｘ＿ｅｍ are derived from the wavelength of the emission peak on the shortest wavelength side of the emission spectrum.

4. In claim 1 or claim 2, the luminescence energy E of the first organic compound Ｇ＿ｅｍ and the emission energy E of the exciplex Ｅｘ＿ｅｍ are derived from the wavelength at the rising edge on the shortest wavelength side of the emission spectrum of the light-emitting element.

5. In any one of claims 1 to 4, The HOMO level and LUMO level of the first organic compound and the HOMO level and LUMO level of the second organic compound are values ​​calculated from the results of CV measurement.

6. In any one of claims 1 to 5, the lowest excited triplet energy level of the second organic compound is equal to or higher than the lowest excited triplet energy level of the first organic compound; a lowest excited triplet energy level of the first organic compound is equal to or higher than a lowest excited triplet energy level of the exciplex;

7. In any one of claims 1 to 6, The light-emitting element, wherein the first organic compound contains iridium.

8. In any one of claims 1 to 7, The second organic compound has a π-electron-deficient heteroaromatic ring skeleton.

9. A light-emitting element according to any one of claims 1 to 8; A display device having at least one of a color filter and a transistor.

10. The display device according to claim 9 ; An electronic device having at least one of a housing and a touch sensor.

11. A light-emitting element according to any one of claims 1 to 8; A lighting device having at least one of a housing and a touch sensor.

Images