Compound

Abstract

Provided is a new compound with which it is possible to provide a blue light-emitting device having good reliability and light-emitting efficiency. This compound is represented by general formula (G1). In general formula (G1), X1-X8 each independently represent any one of: an alkyl group having 3-10 carbon atoms; a substituted or unsubstituted cycloalkyl group having 3-10 carbon atoms; a substituted or unsubstituted cycloalkyl group having 7-10 carbon atoms and having a crosslinked structure; and a substituted or unsubstituted silyl group having 3-20 carbon atoms. At least one of X1-X8 represents either a substituted or unsubstituted cycloalkyl group having 3-10 carbon atoms or a substituted or unsubstituted cycloalkyl group having 7-10 carbon atoms and having a crosslinked structure. All or a portion of hydrogen atoms included in the compound represented by general formula (G1) may be deuterium atoms.

Description

compound

[0001] One aspect of the present invention relates to compounds, light-emitting devices, light-emitting apparatuses, electronic devices, and lighting apparatuses. However, one aspect of the present invention is not limited to these. That is, one aspect of the present invention relates to a product, a method, a method of manufacture, or a method of operation. Or, one aspect of the present invention relates to a process, a machine, a manufacture, or a composition of matter.

[0002] In recent years, research into light-emitting devices utilizing electroluminescence (EL) has been actively conducted. These light-emitting devices have a structure in which an EL layer (containing a light-emitting material) is sandwiched between a pair of electrodes. When a voltage is applied between the pair of electrodes, electrons and holes injected from each electrode recombine in the EL layer, causing the light-emitting material (compound) contained in the EL layer to enter an excited state, and light is emitted when this excited state returns to the ground state. The types of excited states include singlet excited states (S ＊ ) and triplet excited state (T ＊ ) and luminescence from the singlet excited state is called fluorescence, and luminescence from the triplet excited state is called phosphorescence. Furthermore, the statistical generation ratio of these in light-emitting devices is S ＊ : T ＊ It is believed that the ratio is 1:3. Therefore, light-emitting devices using phosphorescent materials that can convert the energy of the triplet excited state into light emission are being actively developed in recent years because they can be obtained with high efficiency.

[0003] In addition to phosphorescent materials, thermally activated delayed fluorescence (TADF) materials are known as materials capable of converting some or all of the energy of a triplet excited state into light emission. TADF materials can generate a singlet excited state from a triplet excited state through reverse intersystem crossing.

[0004] As a light-emitting device using TADF material, a method has been proposed in which the singlet excitation energy of the TADF material is transferred to the fluorescent material by combining it with a fluorescent material, thereby efficiently causing the fluorescent material to emit light (see Patent Document 1).

[0005] Furthermore, regarding the energy transfer of excitation energy from the host material to the guest material in the light-emitting layer of a light-emitting device, it is generally preferable to increase the concentration ratio of the guest material (fluorescent material) to the host material in order to improve the energy transfer efficiency (improve the energy transfer rate) by the Förster mechanism. However, it is known that there is a trade-off relationship where increasing the concentration ratio of the guest material improves the energy transfer rate by the Dexter mechanism, resulting in a decrease in luminescence efficiency. Therefore, increasing the concentration ratio of the guest material has not been an effective means of improving luminescence efficiency.

[0006] Japanese Patent Publication No. 2014-45179

[0007] In one aspect of the present invention, a novel compound is provided. Alternatively, in the EL layer of a light-emitting device, even when the concentration ratio is increased, the singlet excited state (S) of the host material is maintained. ＊ The energy from (hereinafter referred to as singlet excitation energy) is efficiently received, and the triplet excited state (T) of the host material is efficiently received. ＊ The objective is to provide novel compounds in which energy transfer from (hereinafter referred to as triplet excitation energy) is less likely to occur (energy transfer by the Dexter mechanism can be suppressed). In particular, one aspect of the present invention aims to provide novel compounds in which energy transfer by the Dexter mechanism is easily suppressed and energy transfer by the Förster mechanism is easily facilitated.

[0008] Furthermore, one aspect of the present invention provides a novel compound that can be used in a light-emitting device. Furthermore, one aspect of the present invention provides a novel compound that can be used in the EL layer of a light-emitting device. Alternatively, one aspect of the present invention provides a light-emitting device with high luminous efficiency. Alternatively, one aspect of the present invention provides a light-emitting device with high reliability. Alternatively, one aspect of the present invention provides a novel light-emitting device. Alternatively, one aspect of the present invention provides a novel light-emitting device, a novel electronic device, or a novel lighting device.

[0009] Note that the description of these problems does not prevent the existence of other problems. Note that one aspect of the present invention does not need to solve all of these problems. Note that other problems will be apparent from the description in the specification, drawings, claims, etc., and it is possible to extract these other problems from the description in the specification, drawings, claims, etc.

[0010] One aspect of the present invention is a blue fluorescent emitting substance, which is a compound represented by the general formula (G1).

[0011]

[0012] In the above general formula (G1), X １ to X ８ each independently represents any one of an alkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a cycloalkyl group having a cross-linked structure having 7 to 10 carbon atoms which is substituted or unsubstituted, and a substituted or unsubstituted silyl group having 3 to 20 carbon atoms. However, at least one of X １ to X ８ represents either a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms or a cycloalkyl group having a cross-linked structure having 7 to 10 carbon atoms which is substituted or unsubstituted. Note that some or all of the hydrogens possessed by the compound represented by the general formula (G1) may be deuterium.

[0013] Or, another aspect of the present invention is a compound represented by the above general formula (G1), in which four or more of X １ to X ８ are either a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms or a cycloalkyl group having a cross-linked structure having 7 to 10 carbon atoms which is substituted or unsubstituted.

[0014] Or, another aspect of the present invention is a compound represented by the above general formula (G1), in which X １ to X ８The compound is such that four of the elements are either a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, or a substituted or unsubstituted cycloalkyl group having a cross-linked structure having 7 to 10 carbon atoms, and the remaining four elements are an alkyl group having 3 to 10 carbon atoms.

[0015] Alternatively, another aspect of the present invention is a compound in which the alkyl group having 3 to 10 carbon atoms is a tert-butyl group.

[0016] Alternatively, another aspect of the present invention is a compound represented by general formula (G2) in the above configuration.

[0017]

[0018] In the above general formula (G2), X １ , X ２ , X ７ and X ８ Each of these independently represents either a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, or a substituted or unsubstituted cycloalkyl group having a cross-linked structure having 7 to 10 carbon atoms. Note that some or all of the hydrogen atoms in the compound represented by general formula (G2) may be deuterium.

[0019] Alternatively, another aspect of the present invention is a compound in which, in the above configuration, the substituted or unsubstituted C3 to C10 cycloalkyl group and the substituted or unsubstituted C7 to C10 cycloalkyl group having a crosslinked structure are cyclohexyl groups.

[0020] Alternatively, another aspect of the present invention is a compound in which, in the above configuration, the substituted or unsubstituted C3 to C10 cycloalkyl group and the substituted or unsubstituted C7 to C10 cycloalkyl group having a crosslinked structure are adamantyl groups.

[0021] Alternatively, another aspect of the present invention is a compound represented by general formula (G3).

[0022]

[0023] In the above general formula (G3), X ３ ~X ６Each of these independently represents one of the following: an alkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having a cross-linked structure with 7 to 10 carbon atoms, and a substituted or unsubstituted silyl group having 3 to 20 carbon atoms. Note that some or all of the hydrogen atoms in the compound represented by general formula (G3) may be deuterium.

[0024] Alternatively, another aspect of the present invention is a compound represented by the following general formula (G4).

[0025]

[0026] In the above general formula (G4), X ３ ~X ６ Each of these independently represents one of the following: an alkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having a cross-linked structure with 7 to 10 carbon atoms, and a substituted or unsubstituted silyl group having 3 to 20 carbon atoms. Note that some or all of the hydrogen atoms in the compound represented by general formula (G4) may be deuterium.

[0027] Alternatively, in another aspect of the present invention, in the above configuration, X ３ ~X ６ Each of these compounds independently consists of an alkyl group having 3 to 10 carbon atoms and a substituted or unsubstituted silyl group having 3 to 20 carbon atoms.

[0028] Alternatively, in another aspect of the present invention, in the above configuration, X ３ ~X ６ However, it is a compound that is a substituted or unsubstituted branched alkyl group having 3 to 10 carbon atoms.

[0029] Alternatively, in another aspect of the present invention, in the above configuration, X ３ ~X ６ However, it is a compound with a tert-butyl group.

[0030] Alternatively, another aspect of the present invention is a compound represented by the following structural formula.

[0031]

[0032] Alternatively, another aspect of the present invention is a compound represented by the following structural formula.

[0033]

[0034] Another aspect of the present invention is a light-emitting device using the compound of the present invention described above. Furthermore, a light-emitting device formed using the compound of the present invention in an EL layer between a pair of electrodes and in a light-emitting layer contained within the EL layer is also included in the present invention. In addition to the above-mentioned light-emitting device, a light-emitting device having a layer containing the compound in contact with the electrodes (e.g., a cap layer) is also included in the present invention. Furthermore, in addition to the light-emitting device, light-emitting devices having transistors, substrates, etc., are also included in the scope of the invention. Moreover, in addition to these light-emitting devices, electronic devices and lighting devices having microphones, cameras, operation buttons, external connection parts, housings, covers, support bases, or speakers, etc., are also included in the scope of the invention.

[0035] Furthermore, one aspect of the present invention includes a light-emitting device having a light-emitting device, and further includes an illumination device having a light-emitting device. Accordingly, in this specification, a light-emitting device refers to an image display device or a light source (including an illumination device). In addition, modules to which connectors such as FPC (Flexible Printed Circuit) or TCP (Tape Carrier Package) are attached, modules to which a printed circuit board is provided at the end of a TCP, or modules to which an IC (integrated circuit) is directly mounted on a light-emitting device using the COG (Chip On Glass) method are all included as light-emitting devices.

[0036] According to one aspect of the present invention, a novel compound can be provided. Alternatively, in the EL layer of a light-emitting device, even if the concentration ratio is increased, the singlet excited state (S) of the host material can be maintained. ＊ The energy from (hereinafter referred to as singlet excitation energy) is efficiently received, and the triplet excited state (T) of the host material is efficiently received. ＊This invention provides novel compounds in which energy transfer from (hereinafter referred to as triplet excitation energy) is less likely to occur (energy transfer by the Dexter mechanism can be suppressed). In particular, in one aspect of the present invention, it is possible to provide novel compounds in which energy transfer by the Dexter mechanism is easily suppressed and energy transfer by the Förster mechanism is easily facilitated.

[0037] Alternatively, one aspect of the present invention can provide a novel compound that can be used in a light-emitting device. Alternatively, one aspect of the present invention can provide a novel compound that can be used in the EL layer of a light-emitting device. Alternatively, one aspect of the present invention can provide a light-emitting device with high luminous efficiency. Alternatively, one aspect of the present invention can provide a light-emitting device with high reliability. Alternatively, one aspect of the present invention can provide a novel light-emitting device. Alternatively, one aspect of the present invention can provide a novel light-emitting device, a novel electronic device, or a novel lighting device.

[0038] Furthermore, the description of these effects does not preclude the existence of other effects. Moreover, one aspect of the present invention does not necessarily have to possess all of these effects. Other effects are naturally apparent from the description in the specification, drawings, and claims, and it is possible to extract other effects from the description in the specification, drawings, and claims.

[0039] Figure 1A is a diagram showing the structure of a light-emitting device. Figure 1B is a diagram illustrating the light-emitting layer. Figure 2A is a conceptual diagram of energy transfer between a general guest material and a host material. Figure 2B is a conceptual diagram of energy transfer between a compound (guest material) and a host material according to one embodiment of the present invention. Figures 3A, 3B, and 3C are conceptual diagrams of energy transfer between compounds in the light-emitting layer. Figures 4A, 4B, and 4C are conceptual diagrams of energy transfer between compounds in the light-emitting layer. Figures 5A and 5B are conceptual diagrams of energy transfer between compounds in the light-emitting layer. Figures 6A, 6B, and 6C are diagrams representing a light-emitting device. Figures 7A and 7B are a top view and a cross-sectional view of the light-emitting device. Figures 8A and 8B are perspective views showing an example configuration of a display module. Figures 9A and 9B are cross-sectional views showing an example configuration of a display device. Figure 10 is a perspective view showing an example configuration of a display device. Figure 11 is a cross-sectional view showing an example configuration of a display device. Figure 12 is a cross-sectional view showing an example configuration of a display device. Figure 13 is a cross-sectional view showing an example configuration of a display device. Figures 14A, 14B, 14C, and 14D show examples of electronic devices. Figures 15A, 15B, 15C, 15D, 15E, and 15F show examples of electronic devices. Figures 16A, 16B, 16C, 16D, 16E, 16F, and 16G show examples of electronic devices. Figures 17A, 17B, and 17C show the 1H NMR spectrum of 1,6 mmAdtBuDPhAPrn. Figure 18 shows the absorption and PL spectra of 1,6 mmAdtBuDPhAPrn in a toluene solution. Figures 19A, 19B, and 19C show the 1H NMR spectrum of 1,6 mmChtBuDPhAPrn. Figure 20 shows the absorption and PL spectra of 1,6 mmchtBuDPhAPrn in a toluene solution. Figure 21 shows the luminance-current density characteristics of light-emitting devices 1-1 and 1-2. Figure 22 shows the luminance-voltage characteristics of light-emitting devices 1-1 and 1-2. Figure 23 shows the current efficiency-current density characteristics of light-emitting devices 1-1 and 1-2.Figure 24 shows the current density-voltage characteristics of light-emitting devices 1-1 and 1-2. Figure 25 shows the blue index-current density characteristics of light-emitting devices 1-1 and 1-2. Figure 26 shows the external quantum efficiency-current density characteristics of light-emitting devices 1-1 and 1-2. Figure 27 shows the electroluminescence spectra of light-emitting devices 1-1 and 1-2. Figure 28 shows the chromaticity diagrams of light-emitting devices 1-1 and 1-2. Figure 29 shows the absorption and PL spectra of PtON-TBBI and 1,6 mm chtBuDPhAPrn in solution. Figure 30 shows the absorption and PL spectra of PtON-TBBI and 1,6 mm AdtBuDPhAPrn in solution. Figure 31 shows the distance from the luminescent phose to the tip of the protecting group of 1,6 mm chtBuDPhAPrn. Figure 32 shows the distance from the luminescent phosphat to the tip of the protecting group in 1,6 mm AdtBuDPhAPrn. Figure 33 shows the distance from the luminescent phosphat to the tip of the protecting group in 1,6 mm tBuDPhAPrn.

[0040] The embodiments of the present invention will be described in detail below with reference to the drawings. However, the present invention is not limited to the following description, and its form and details can be modified in various ways without departing from the spirit and scope of the present invention. Accordingly, the present invention shall not be interpreted as being limited to the contents of the embodiments shown below.

[0041] Please note that the positions, sizes, and ranges of each component shown in the drawings may not represent their actual positions, sizes, and ranges for the sake of ease of understanding. Therefore, the disclosed invention is not necessarily limited to the positions, sizes, and ranges disclosed in the drawings.

[0042] Furthermore, in this specification and other documents, when describing the structure of the invention using drawings, reference numerals that refer to the same thing will be used consistently across different drawings.

[0043] Furthermore, in this specification, the ordinal numbers "first," "second," etc., are used for convenience only and do not limit the number of components or the order of components. The order of components includes, for example, the order of processes or the order of stacking. In other words, the ordinal numbers used in the embodiments of this specification may not match the ordinal numbers used in the claims. Also, the ordinal numbers used in the examples of this specification may not match the ordinal numbers used in the claims. Also, the ordinal numbers used in the embodiments of this specification may not match the ordinal numbers used in the examples of this specification.

[0044] Furthermore, in this specification, etc., the singlet excited state (S ＊ A singlet state is a singlet state that has an excitation energy. The S1 level is the lowest singlet excitation energy level, and is the excitation energy level of the lowest singlet excited state (S1 state). Also, a triplet excited state (T ＊ ) refers to a triplet state that has an excitation energy. The T1 level is the lowest level of the triplet excitation energy levels, and is the excitation energy level of the lowest triplet excited state (T1 state). Note that in this specification, even when simply referred to as a singlet excited state and a singlet excitation energy level, it may refer to the S1 state and the S1 level. Similarly, even when referred to as a triplet excited state and a triplet excitation energy level, it may refer to the T1 state and the T1 level.

[0045] Furthermore, in this specification, a fluorescent material is a compound that emits light in the visible light region or near-infrared region when relaxing from a singlet excited state to the ground state. A phosphorescent material is a compound that emits light in the visible light region or near-infrared region at room temperature when relaxing from a triplet excited state to the ground state. In other words, a phosphorescent material is one of the compounds that can convert triplet excitation energy into light emission.

[0046] In this specification, a photoluminescence (PL) spectrum refers to a spectrum obtained by spectrally analyzing the emission from a sample irradiated with excitation light in fluorescence photometry, and measuring the emission intensity distribution at each wavelength. It may also be called an emission spectrum. An emission spectrum may contain both a fluorescent component and a phosphorescent component. In this specification, an emission spectrum consisting of a fluorescent component may be specifically called a fluorescence spectrum, and an emission spectrum consisting of a phosphorescent component may be specifically called a phosphorescent spectrum.

[0047] (Embodiment 1) This embodiment describes a compound according to one aspect of the present invention. The compound according to one aspect of the present invention is a compound represented by the following general formula (G1).

[0048]

[0049] However, in the above general formula (G1), X １ ~X ８ Each of these independently represents one of the following: an alkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 7 to 10 carbon atoms and a cross-linked structure, and a substituted or unsubstituted silyl group having 3 to 20 carbon atoms.

[0050] In addition, in the above general formula (G1), X １ ~X ８ At least one of these represents either a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, or a substituted or unsubstituted cycloalkyl group having 7 to 10 carbon atoms and a crosslinked structure.

[0051] A compound according to one embodiment of the present invention, having the above configuration, is a material (fluorescent material) that has the function of converting singlet excitation energy into light emission, and therefore can be used as a guest material in the light-emitting layer of a light-emitting device together with a host material. Furthermore, since the peak of the emission spectrum of a compound according to one embodiment of the present invention is in the blue light emission region (wavelength 450 nm to 520 nm), it is possible to provide a light-emitting device that exhibits good blue light emission.

[0052] A compound according to one aspect of the present invention has at least one protecting group (a C3 to C10 alkyl group, a substituted or unsubstituted C3 to C10 cycloalkyl group, a substituted or unsubstituted C7 to C10 cycloalkyl group having a crosslinked structure, and a substituted or unsubstituted C3 to C20 silyl group) that suppresses triplet excitation energy transfer from the host material to the luminescent phosphophore (pyrene skeleton) that contributes to luminescence. The protecting group of a compound according to one aspect of the present invention is such that each of the two phenyl groups of the two diphenylamino groups in the compound has two protecting groups.

[0053] One embodiment of the present invention provides a compound in which two diphenylamino groups, each having four protecting groups, are bonded symmetrically to the luminescent phore, thereby increasing the quantum yield. Furthermore, in one embodiment of the present invention, the use of diphenylamino groups suppresses the increase in molecular weight and maintains sublimation properties.

[0054] Furthermore, in a compound according to one embodiment of the present invention, since the protecting group is bonded to the phenyl group of the diphenylamino group bonded to the pyrene skeleton, which is the luminescent phosphodiester, the protecting group can be positioned to cover the luminescent phosphodiester, and a distance can be maintained between the host material and the luminescent phosphodiester that makes energy transfer based on the Dexter mechanism less likely to occur, thus keeping the two apart. In addition, by using a phenyl group having a protecting group, the effect of covering the luminescent phosphodiester is increased, making energy transfer based on the Dexter mechanism even less likely to occur. Moreover, by having at least one of the protecting groups be a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, or a substituted or unsubstituted cycloalkyl group having a cross-linked structure having 7 to 10 carbon atoms, it is possible to maintain the distance between the host material and the luminescent phosphodiester at a distance that further suppresses energy transfer based on the Dexter mechanism and does not hinder energy transfer based on the Förster mechanism, thereby making it possible to obtain a light-emitting device with better luminescence efficiency and reliability.

[0055] Furthermore, the compound represented by the above general formula (G1) is X １ ~X ８Preferably, four or more of these are either substituted or unsubstituted cycloalkyl groups having 3 to 10 carbon atoms, or substituted or unsubstituted cycloalkyl groups having a crosslinked structure having 7 to 10 carbon atoms. By having such a configuration, the distance between the light phosphonate and the host material can be effectively suppressed based on the Dexter mechanism, while also being effectively maintained at a distance that does not hinder energy transfer based on the Förster mechanism, thereby making it possible to obtain a light-emitting device with better luminescence efficiency and reliability.

[0056] Furthermore, the compound represented by the above general formula (G1) is X １ ~X ８ Preferably, the compound is such that four of the members are either a substituted or unsubstituted C3 to C10 cycloalkyl group, or a substituted or unsubstituted C7 to C10 cycloalkyl group having a crosslinked structure, and the remaining four members are C3 to C10 alkyl groups. A compound according to one embodiment of the present invention having such a configuration can effectively suppress energy transfer based on the Dexter mechanism between the light phosphonate and the host material, while effectively maintaining a distance that does not hinder energy transfer based on the Förster mechanism. Furthermore, it can be synthesized relatively easily, resulting in a light-emitting device with good luminescence efficiency and reliability, and at low cost. In this case, the C3 to C10 alkyl group is preferably a branched alkyl group, and more preferably a tert-butyl group because it can be synthesized relatively easily while suppressing the sublimation temperature.

[0057] In other words, the compound according to one aspect of the present invention is preferably a compound represented by the following general formula (G2).

[0058]

[0059] In the above general formula (G2), X １ , X ２ , X ７ and X ８Each of these independently represents either a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, or a substituted or unsubstituted cycloalkyl group having 7 to 10 carbon atoms and a cross-linked structure.

[0060] A compound according to one embodiment of the present invention having such a configuration can be synthesized inexpensively, in addition to having the same properties and effects as the general formula (G1) described above.

[0061] In the compounds represented by the above general formula (G1) and the compounds represented by the above general formula (G2), the substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms is preferable because it can be synthesized relatively easily.

[0062] In other words, the compound according to one aspect of the present invention is preferably a compound represented by the following general formula (G3).

[0063]

[0064] In the above general formula (G3), X ３ ~X ６ Each of these independently represents one of the following: an alkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 7 to 10 carbon atoms and a cross-linked structure, and a substituted or unsubstituted silyl group having 3 to 20 carbon atoms.

[0065] Furthermore, in the compounds represented by the above general formula (G1) and the compounds represented by the above general formula (G2), the cycloalkyl group having a substituted or unsubstituted crosslinked structure with 7 to 10 carbon atoms is preferably an unsubstituted adamantyl group because it can be synthesized relatively easily.

[0066] In other words, the compound according to one embodiment of the present invention is preferably a compound represented by the following general formula (G4).

[0067]

[0068] In the above general formula (G4), X ３ ~X ６Each of these independently represents one of the following: an alkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 7 to 10 carbon atoms and a cross-linked structure, and a substituted or unsubstituted silyl group having 3 to 20 carbon atoms.

[0069] In the above general formula (G3) and the above general formula (G4), X ３ ~X ６ It is preferable that the emission wavelength can be adjusted by using either an alkyl group having 3 to 10 carbon atoms, or a substituted or unsubstituted silyl group having 3 to 20 carbon atoms. ３ ~X ６ It is more preferable that the alkyl group has 3 to 10 carbon atoms because it can suppress intermolecular interactions, it is even more preferable that the alkyl group is branched because the bond is less likely to break in the excited state than a linear alkyl group, and it is especially preferable that the group is a tert-butyl group because it provides good reliability and luminescence efficiency and can be synthesized relatively easily.

[0070] In addition, specific examples of alkyl groups having 3 to 10 carbon atoms in the above general formulas (G1) to (G4) include, for example, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, heptyl group, octyl group, and the like.

[0071] Furthermore, in the above general formulas (G1) to (G4), specific examples of cycloalkyl groups having 3 to 10 carbon atoms include, for example, a cyclopropyl group, a cyclobutyl group, a cyclohexyl group, and the like. Specific examples of cases where the above cycloalkyl groups have substituents include alkyl groups having 1 to 7 carbon atoms such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, and a hexyl group; cycloalkyl groups having 5 to 7 carbon atoms such as a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and an 8,9,10-trinorbornyl group; and aryl groups having 6 to 12 carbon atoms such as a phenyl group, a naphthyl group, and a biphenyl group.

[0072] Furthermore, in the above general formulas (G1) to (G4), specific examples of cycloalkyl groups having a crosslinking structure with 7 to 10 carbon atoms include, for example, an adamantyl group, a bicyclo[2.2.1]heptyl group, and a tricyclo[5.2.1.0]heptyl group. ２，６ Examples include decyl groups, bicyclo[3.3.1]nonyl groups, noadamantyl groups, etc. Specific examples of cases where the cycloalkyl group having the above-mentioned crosslinking structure has substituents include C1 to C7 alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, and hexyl groups; C5 to C7 cycloalkyl groups such as cyclopentyl, cyclohexyl, cycloheptyl, and 8,9,10-trinorbornyl groups; and C6 to C12 aryl groups such as phenyl, naphthyl, and biphenyl groups.

[0073] Furthermore, in the above general formulas (G1) to (G4), specific examples of silyl groups having 3 to 20 carbon atoms include, for example, trimethylsilyl group, triethylsilyl group, tert-butyldimethylsilyl group, triisopropylsilyl group, and triphenylsilyl group. Specific examples of cases where the above silyl groups having 3 to 20 carbon atoms have substituents include alkyl groups having 1 to 7 carbon atoms such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, and hexyl group, cycloalkyl groups having 5 to 7 carbon atoms such as cyclopentyl group, cyclohexyl group, cycloheptyl group, and 8,9,10-trinorbornyl group, and aryl groups having 6 to 12 carbon atoms such as phenyl group, naphthyl group, and biphenyl group.

[0074] Furthermore, some or all of the hydrogen atoms in the compounds of one embodiment of the present invention represented by the above general formulas (G1) to (G4) may be deuterium.

[0075] In one embodiment of the present invention, the compound is a cycloalkyl group having 3 to 10 carbon atoms with at least one protected group being substituted or unsubstituted, or a cycloalkyl group having a crosslinked structure with 7 to 10 carbon atoms with at least one protected group being substituted or unsubstituted. This makes it possible for the compound in one embodiment of the present invention to maintain the distance between the host material and the luminescent phosphatidyl at a distance that further suppresses energy transfer based on the Dexter mechanism while also not hindering energy transfer based on the Förster mechanism.

[0076] Here, the distances from the luminescent phore to the tip of the protecting group for N,N'-bis(3,5-dicyclohexylphenyl)-N,N'-bis(3,5-di-tert-butylphenyl)pyrene-1,6-diamine (abbreviated as 1,6mmchtBuDPhAPrn), a compound according to one aspect of the present invention, N,N'-bis[3,5-di(2-adamantyl)phenyl]-N,N'-bis(3,5-di-tert-butylphenyl)pyrene-1,6-diamine (abbreviated as 1,6mmAdtBuDPhAPrn), and the comparative compound N,N,N',N'-tetrakis(3,5-di-tert-butylphenyl)pyrene-1,6-diamine (abbreviated as 1,6mmtBuDPhAPrn) are calculated and shown in Figures 31 to 33. Furthermore, the structural formulas for 1,6mm chtBuDPhAPrn, 1,6mm AdtBuDPhAPrn, and 1,6mm tBuDPhAPrn are shown below.

[0077]

[0078] The distance between the luminescent phosphodiolus and the tip of the protecting group was calculated by performing molecular orbital calculations and determining the distance from the nitrogen atom of the diphenylamine bonded to the pyrene ring to the furthest atom of the protecting group on that diphenylamine, for the molecular structure after structural optimization.

[0079] Molecular orbital calculations were performed using Gaussian 16 as the quantum chemistry calculation program, and the calculations were performed on a high-performance computer (HPE Apollo 6500). The most stable structure in the singlet ground state was calculated using density functional theory (DFT). Vibrational analysis was performed for each most stable structure. The basis set 6-311G was applied to all atoms. Furthermore, to improve calculation accuracy, a p-function was added as a polarization basis set for hydrogen atoms, and a d-function was added for all atoms except hydrogen. The functional used was B3LYP. In DFT, the total energy of a molecule is expressed as the sum of potential energy, interelectron electrostatic energy, electron kinetic energy, and exchange-correlation energy, which includes all complex interelectron interactions. Also, in DFT, the exchange-correlation interaction is approximated by a functional (meaning a function of a function) of the one-electron potential expressed in terms of electron density, so the electronic state can be determined with higher accuracy.

[0080] As shown in Figures 31 to 33, the compounds 1,6mmchtBuDPhAPrn and 1,6mmAdtBuDPhAPrn, which are compounds according to one embodiment of the present invention, have a distance from the luminescent phore to the tip of the protecting group of 0.86 nm to 0.89 nm, while the comparative compound 1,6mmtBuDPhAPrn has a distance of 0.71 nm. 1,6mmchtBuDPhAPrn and 1,6mmAdtBuDPhAPrn can more effectively suppress energy transfer based on the Dexter mechanism by having a longer distance from the luminescent phore to the tip of the protecting group than 1,6mmtBuDPhAPrn. However, if the distance from the luminescent phore to the tip of the protecting group is too long, it will also suppress energy transfer based on the Förster mechanism, so it is preferable that the distance from the luminescent phore to the tip of the protecting group is not too long. Thus, by using 1,6mmchtBuDPhAPrn and 1,6mmAdtBuDPhAPrn, which are compounds according to one aspect of the present invention, energy transfer based on the Dexter mechanism can be more effectively suppressed, and energy transfer based on the Förster mechanism can be made dominant, making it possible to obtain a light-emitting device with better luminescence efficiency and reliability.

[0081] Next, specific examples of compounds represented by the above general formulas (G1) to (G4) are shown in structural formulas (100) to (123) below. However, the specific examples of compounds represented by general formulas (G1) to (G4) are not limited to these.

[0082]

[0083]

[0084]

[0085]

[0086]

[0087]

[0088] <Synthesis Method of Compound Represented by General Formula (G1)> Next, as an example of an organic compound according to one aspect of the present invention, a synthesis method of an organic compound represented by the following general formula (G1) will be described. Note that various reactions can be applied as the synthesis method for general formula (G1), and the method is not limited to the one described below.

[0089]

[0090] However, in the organic compound represented by the above general formula (G1), X １ ~X ８ Each of the following independently represents one of the following: an alkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 7 to 10 carbon atoms and a cross-linked structure, and a substituted or unsubstituted silyl group having 3 to 20 carbon atoms. However, X １ ~X ８ At least one of the following represents either a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, or a substituted or unsubstituted cycloalkyl group having 7 to 10 carbon atoms and a cross-linked structure. Some or all of the hydrogen atoms in the compound represented by general formula (G1) may be deuterium.

[0091] The organic compound represented by the above general formula (G1) can be synthesized by the following synthesis scheme (A-1).

[0092]

[0093] In synthesis scheme (A-1), the organic compound represented by general formula (G1) is obtained by coupling reaction or nucleophilic substitution reaction of compounds (a1), (a2), and (a3) ​​under a suitable solvent. It is preferable to use a Buchwald-Hartwig reaction with a palladium catalyst as the coupling reaction.

[0094] In the above compound (a1), Z １ ~Z ２ Each of these independently represents either a halogen or a trifluoromethanesulfonyl group. Note that some or all of the hydrogen atoms in compound (a1) may be deuterium.

[0095] In the above compounds (a2) and (a3), X １ ~X ８ Each of the following independently represents one of the following: an alkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 7 to 10 carbon atoms and a cross-linked structure, and a substituted or unsubstituted silyl group having 3 to 20 carbon atoms. However, X １ ~X ８ At least one of these represents either a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, or a substituted or unsubstituted cycloalkyl group having 7 to 10 carbon atoms and a cross-linked structure. Some or all of the hydrogen atoms in compounds (a2) and (a3) ​​may be deuterium.

[0096] When the Buchwald-Hartwig reaction is carried out using the above synthesis scheme (A-1), suitable palladium catalysts include palladium(II) acetate, tetrakis(triphenylphosphine)palladium(O), bis(triphenylphosphine)palladium(II) dichloride, and tris(dibenzylideneacetone)dipalladium(O).

[0097] Ligands for the above palladium catalyst include tri-tert-butylphosphine, 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl, di(1-adamantyl)-N-butylphosphine, (±)-2,2'-bis(diphenylphosphino)-1,1'-binaphthyl, tri(ortho-tolyl)phosphine, triphenylphosphine, 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (abbreviated as Xantphos), and tricyclohexylphosphine.

[0098] When the Buchwald-Hartwig reaction is carried out using the above synthesis scheme (A-1), suitable bases include organic bases such as sodium tert-butoxide and potassium tert-butoxide, and inorganic bases such as potassium carbonate and sodium carbonate.

[0099] When the Buchwald-Hartwig reaction is carried out using the above synthesis scheme (A-1), suitable solvents include toluene, xylene, mesitylene, benzene, tetrahydrofuran, and dioxane. However, the solvents that can be used are not limited to these.

[0100] Furthermore, the reactions carried out in the above synthesis scheme (A-1) are not limited to the Buchwald-Hartwig reaction, but can also be performed using organotin compounds, coupling reactions using Grignard reagents, nucleophilic substitution reactions, etc.

[0101] While organic compounds according to one aspect of the present invention can be synthesized as described above, the present invention is not limited thereto, and may be synthesized by other synthesis methods.

[0102] This embodiment can be used in any combination with other embodiments and examples.

[0103] (Embodiment 2) This embodiment describes an example of a light-emitting device in which a compound according to one aspect of the present invention is preferably used. As shown in Figure 1A, the light-emitting device has a structure in which an organic compound layer 103 is sandwiched between a pair of electrodes, which consist of a first electrode 101 (shown as an anode in Figure 1A) and a second electrode 102 (shown as a cathode in Figure 1A). The organic compound layer 103 has at least a light-emitting layer 113, and may also be provided with functional layers such as a hole injection layer 111, a hole transport layer 112, an electron transport layer 114, and an electron injection layer 115.

[0104] Furthermore, the light-emitting layer 113 contains a light-emitting substance (guest material) and a host material. In the light-emitting device, by applying a voltage between a pair of electrodes, electrons are injected from the cathode and holes from the anode into the organic compound layer 103, and an electric current flows. At this time, excitons are generated when carriers (electrons and holes) recombine in the light-emitting layer 113, and the excitation energy of the excitons is converted into light emission, thereby producing light emission from the light-emitting device. In this embodiment, as shown in Figure 1B, it is preferable that the light-emitting layer 113 contains a compound 332 that functions as a light-emitting central substance (guest material) and acts as an energy acceptor, and a compound 331 that functions as a host material and acts as an energy donor. Therefore, in this embodiment, the case in which a compound according to one aspect of the present invention is used as the light-emitting central substance (guest material) will be described. Note that there may be multiple compounds that function as host materials in the light-emitting layer 113.

[0105] Of the excitons generated by carrier recombination, singlet excitons account for 25% and triplet excitons account for 75%. Therefore, it is preferable to contribute triplet excitons to light emission in addition to singlet excitons in order to improve the luminescence efficiency of the light-emitting device. Here, the concept of energy transfer occurring between the guest material and the host material in the light-emitting layer 113 will be explained using Figure 2. Figure 2A shows the structure of a typical guest material (fluorescent material) and illustrates the concept of energy transfer between the guest material and the host material when this is used. Figure 2B shows the structure of compound 332 according to one embodiment of the present invention and illustrates the concept of energy transfer between the guest material and the host material when this is used as the guest material.

[0106] Figure 2A shows the presence of the host material compound 331 and the guest material fluorescent substance 124. The fluorescent substance 124 is a common fluorescent substance that has a luminescent phore 124a but does not have a protecting group.

[0107] Figure 2B shows a configuration in which a host material compound 331 and a guest material, a compound (fluorescent material) 332 according to one embodiment of the present invention. Compound 332 is a fluorescent material that functions as an energy acceptor in a light-emitting device, and has a luminescent phosphodiolus 332a and a protecting group 332b. The protecting group 332b has the function of keeping the two apart by maintaining a distance such that energy transfer based on the Dexter mechanism from compound (host material) 331 to luminescent phosphodiolus 332a is unlikely to occur.

[0108] As shown in Figures 2A and 2B, in the light-emitting layer 113, the host material compound 331 and the guest materials compound (fluorescent substance) 124 and compound (fluorescent substance) 332 are all located close together. Therefore, as shown in Figure 2A, if compound (fluorescent substance) 124 does not have a protecting group, the distance between the light-emitting phosphodiol 124a and compound 331 becomes short, and energy transfer from compound 331 to compound (fluorescent substance) 124 occurs via the Förster mechanism (Route A in Figure 2A). Ｆ) and energy transfer by the Dexter mechanism (Route A in Figure 2A) Ｄ Both of the above can occur. When the guest material is a fluorescent material, energy transfer of triplet excitation energy occurs from the host material to the guest material via the Dexter mechanism, and even if a triplet excited state is generated in the guest material, the triplet excitation energy is deactivated non-radiatively. For this reason, when the guest material is a fluorescent material, energy transfer of triplet excitation energy from the host material to the guest material via the Dexter mechanism is one of the causes of a decrease in the luminescence efficiency of the light-emitting device.

[0109] On the other hand, in Figure 2B, since the guest material compound (fluorescent substance) 332 has a protecting group 332b, the distance between the luminescent phosphodiolus 332a and the host material compound 331 can be maintained at an appropriate length. This allows for energy transfer via the Dexter mechanism (Route A Ｄ This can suppress the following:

[0110] Here, the luminescent group 124a of compound (fluorescent material) 124 shown in Figure 2A and the luminescent group 332a of compound (fluorescent material) 332 shown in Figure 2B refer to the atomic group (skeleton) from which the light emitted by the fluorescent material originates. The luminescent groups (124a, 332a) generally have π bonds and preferably contain aromatic rings, and preferably have fused aromatic rings or fused heteroaromatic rings. In one embodiment of the present invention, the luminescent group of the compound is a pyrene ring. Since the T1 level of the pyrene ring is low, the spin density distribution of compounds containing a pyrene ring is distributed in the pyrene ring in the T1 state. Therefore, by suppressing the transfer of triplet excitation energy to the pyrene ring, the transfer of triplet excitation energy from the host material to the guest material can be suppressed.

[0111] Furthermore, in order to prevent the transfer of triplet excitation energy in compound (fluorescent material) 332 from occurring at the luminescent phosphat 332a, it is preferable that the protecting group 332b of compound (fluorescent material) 332 shown in Figure 2B has a T1 level higher than the T1 levels of the luminescent phosphat 332a and the host material compound 331.

[0112] Specific examples of the protecting group 332b of compound 332 in one embodiment of the present invention include, as described in Embodiment 1, C3 to C10 alkyl groups, substituted or unsubstituted C3 to C10 cycloalkyl groups, substituted or unsubstituted C7 to C10 cycloalkyl groups having a crosslinked structure, substituted or unsubstituted C3 to C20 silyl groups, etc. Since such protecting groups 332b have a bulky structure, they can maintain an appropriate distance between the luminescent phose 332a of the guest material compound 332 and the host material compound 331, thereby suppressing energy transfer from the host material to the luminescent phose based on the Dexter mechanism.

[0113] Furthermore, by having at least one of the protecting groups be either a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, or a substituted or unsubstituted cycloalkyl group having a cross-linked structure having 7 to 10 carbon atoms, it becomes possible to maintain the distance between the light phosphonate 332a and compound 331 at a distance that suppresses energy transfer based on the Dexter mechanism while not suppressing energy transfer based on the Förster mechanism, compared to a compound without such a protecting group. Among the protecting groups 332b, a cyclohexyl group or an adamantyl group is preferred. As a result, it becomes possible to obtain a light-emitting device with better reliability and higher luminescence efficiency.

[0114] Next, the configuration of the light-emitting layer of a light-emitting device according to one aspect of the present invention will be described.

[0115] <Example of Light-Emitting Layer Configuration 1> In this configuration example, the light-emitting layer 113 in the light-emitting device has a compound 331 that functions as a host material and a compound 332 that functions as a light-emitting substance (guest material). The example shows the case where a TADF material is used as compound 331 and a fluorescent light-emitting substance is used as compound 332 that functions as a light-emitting substance (guest material). Therefore, it is preferable to use a compound according to one aspect of the present invention as compound 332, which is a fluorescent light-emitting substance. An example of the correlation of energy levels in the light-emitting layer 113 in this configuration example is shown in Figure 3A. The notation and symbols shown in Figure 3A are as follows: ・Host (331): Compound 331 ・Guest (332): Compound 332 ・T Ｃ１ : T1 level of compound 331, S Ｃ１ : S1 level of compound 331, S Ｇ : S1 level of compound 332, T Ｇ : T1 level of compound 332

[0116] In this configuration example, compound 331 is a material having TADF, and therefore has the function of converting triplet excitation energy to singlet excitation energy by upconversion (Route A in Figure 3A). １ The singlet excitation energy possessed by the excited compound 331 is rapidly transferred to compound 332 (Route A in Figure 3A). ２ ). At this time, the S of compound 331 Ｃ１ and S of compound 332 Ｇ The relationship is, S Ｃ１ ≥S Ｇ It is preferable that S Ｃ１ The energy of the extrapolation line is obtained by drawing a tangent line at the short-wavelength tail of the fluorescence spectrum of compound 331. Ｇ This is the energy of the wavelength at the absorption edge of the absorption spectrum of compound 332.

[0117] The absorption edge of the absorption spectrum can be determined by measuring the absorption spectrum of the target substance in a thin film state or in a thin film doped with the target substance in a matrix material, and obtaining it from a Tauc plot assuming a direct transition. Alternatively, the absorption spectrum of the solution can be measured, a tangent line can be drawn at the long-wavelength half-value of the longest wavelength peak or shoulder peak observed in the absorption spectrum, and the absorption edge can be calculated from the intersection of this tangent line with the horizontal axis (wavelength) or baseline. There are no particular restrictions on the solvent of the solution, but solvents with relatively low polarity, such as toluene and chloroform, are preferred.

[0118] In this way, the triplet excitation energy generated in the excited compound 331 is taken via the square root A １ and Route A ２ Through this process, energy is transferred to the S1 level of the guest material compound 332, thereby efficiently causing compound 332 to emit light and increasing the luminescence efficiency of the light-emitting device. Note that Route A ２ In this configuration, the excited compound 331 functions as an energy donor, and compound 332 functions as an energy acceptor. However, in the light-emitting layer 113 of the light-emitting device shown in this example, in addition to the above, there is a pathway through which the triplet excitation energy generated in the excited compound 331 moves to the T1 level of compound 332 (Route A in Figure 3A). ３ ) can also compete with such energy transfer (Route A ３ When this occurs, the fluorescent material compound 332 cannot contribute the triplet excitation energy to light emission, thus reducing the luminescence efficiency of the light-emitting device.

[0119] Generally, two known energy transfer mechanisms between molecules are the Förster mechanism (dipole-dipole interaction) and the Dexter mechanism (electron exchange interaction). The Dexter mechanism predominantly occurs when the distance between the energy donor compound and the energy acceptor compound is 1 nm or less; the closer the distance, the more easily energy transfer occurs. Therefore, the Dexter mechanism is more likely to occur as the concentration of the energy acceptor compound increases. Consequently, as in this example, if the energy acceptor compound 332 is a fluorescent material with a low triplet excitation energy level, and its concentration increases, the triplet excitation energy of the excited compound 331, the energy donor, is transferred via the Dexter mechanism through route A. ３ Energy transfer and subsequent non-radiative deactivation become dominant. Therefore, Route A ３ To suppress this, it is important to maintain an appropriate distance between compound 331 and compound 332 so that energy transfer by the Dexter mechanism is unlikely to occur.

[0120] Furthermore, the T1 level (T) of compound 332, which is an energy acceptor. Ｇ ) is often an energy level derived from the luminescent phosphatid of compound 332. Therefore, in the luminescent layer 113, route A ３ To suppress this, it is important to maintain an appropriate distance between the excited compound 331 (energy donor) and the luminescence phosphophore of compound 332.

[0121] A common method for maintaining an appropriate distance between the energy donor and the light-emitting phosphonate of the energy acceptor is to lower the concentration of the energy acceptor in the mixed film. However, lowering the concentration of the energy acceptor suppresses not only the energy transfer based on the Dexter mechanism from the energy donor to the energy acceptor, but also the energy transfer based on the Förster mechanism. In that case, Route A ２Since it is based on the Förster mechanism, problems such as a decrease in the luminous efficiency of the light-emitting device and a decrease in reliability occur. On the other hand, the compound of one aspect of the present invention has a light-emitting group and a protecting group in a part of its structure, and when it functions as an energy acceptor in the light-emitting layer 113, the protecting group has a function of maintaining the distance between the energy donor and the light-emitting group at an appropriate length. Therefore, when the compound of one aspect of the present invention is used as the compound 332 of this configuration, the distance between the compound 332 and the compound 331 can be maintained at an appropriate length.

[0122] Also, when the distance between the energy donor and the energy acceptor is 1 nm or less, the Dexter mechanism becomes dominant, and when it is 1 nm or more and 10 nm or less, the Förster mechanism becomes dominant. Therefore, the protecting group is preferably a bulky substituent that extends in the range of 1 nm or more and 10 nm or less from the light-emitting group, and the protecting group possessed by the compound of one aspect of the present invention preferably has the protecting groups listed above.

[0123] Therefore, by using the compound of one aspect of the present invention as the compound 332, even if the concentration of the compound 332 is increased, the energy transfer by the Dexter mechanism can be suppressed while increasing the energy transfer rate by the Förster mechanism. That is, the singlet excitation energy transfer (route A Ｃ１ ) from the S1 level (S Ｇ ) of the excited compound 331 to the S1 level (S ２ ) of the compound 332 becomes likely to occur, while the transfer of triplet excitation energy (route A Ｇ ) from the excited compound 331 to the T1 level (T ３ ) of the compound 332 (energy transfer by the Dexter mechanism) can be made less likely to occur, and route A ３It is possible to increase the luminous efficiency of the light-emitting device while suppressing the decrease in luminous efficiency associated with energy transfer. Further, by increasing the energy transfer rate by the Förster mechanism, the excitation lifetime of the energy acceptor in the light-emitting layer is shortened, so that the reliability of the light-emitting device can be improved. Specifically, the concentration of Compound 332 in the light-emitting layer 113 is preferably 1 wt% or more and 50 wt% or less, more preferably 5 wt% or more and 30 wt% or less, and still more preferably 5 wt% or more and 20 wt% or less, relative to Compound 331.

[0124] <Configuration Example 2 of Light-Emitting Layer> In this configuration example, the light-emitting layer 113 in the light-emitting device has Compound 331, Compound 332, and Compound 333, and Compound 331 and Compound 333 are a combination that forms an exciplex. The case where a fluorescent light-emitting substance is used as Compound 332 that functions as a light-emitting substance (guest material) is shown. Therefore, the compound of one aspect of the present invention is preferably used as Compound 332 which is a fluorescent light-emitting substance. An example of the correlation of energy levels in the light-emitting layer 113 in this configuration example is as shown in FIG. 3B. The notations and symbols shown in FIG. 3B are as follows. ・Comp(331): Compound 331 ・Comp(333): Compound 333 ・Guest(332): Compound 332 ・S Ｃ１ : S1 level of Compound 331 ・T Ｃ１ : T1 level of Compound 331 ・S Ｃ３ : S1 level of Compound 333 ・T Ｃ３ : T1 level of Compound 333 ・S Ｇ : S1 level of Compound 332 ・T Ｇ : T1 level of Compound 332 ・S Ｅ : S1 level of exciplex ・T Ｅ : T1 level of exciplex

[0125] The combination of compound 331 and compound 333 can be any combination capable of forming an excited complex, but it is more preferable that one compound has the function of transporting holes (hole transport) and the other compound has the function of transporting electrons (electron transport). In this case, it becomes easier to form a donor-acceptor type excited complex, and the excited complex can be formed efficiently. Furthermore, when the combination of compound 331 and compound 333 is a combination of a hole-transporting compound and an electron-transporting compound, the carrier balance can be easily controlled by the mixing ratio. Specifically, a ratio of hole-transporting compound to electron-transporting compound in the range of 1:9 to 9:1 (by weight) is preferred. Moreover, since the carrier balance can be easily controlled with this configuration, the carrier recombination region can also be easily controlled.

[0126] Furthermore, as a combination of host materials that efficiently forms an excited complex, it is preferable that the HOMO level of one of compound 331 and compound 333 is higher than the HOMO level of the other, and the LUMO level of one is higher than the LUMO level of the other. Alternatively, the HOMO level of compound 331 may be equivalent to that of compound 333, or the LUMO level of compound 331 may be equivalent to that of compound 333.

[0127] Furthermore, the LUMO and HOMO levels of a compound can be derived from the electrochemical properties (reduction potential and oxidation potential) of the compound, which are measured by cyclic voltammetry (CV).

[0128] As shown in Figure 3B, the S1 level (S) of the excited complex formed by compound 331 and compound 333 Ｅ ) and T1 level (T Ｅ ) are adjacent energy levels (Root A in Figure 3B) ６ reference).

[0129] Excitation energy levels of the excited complex (S Ｅ and T Ｅ ) is the S1 level (S Ｃ１ and SＣ３ Because this becomes lower, it becomes possible to form an excited state at a lower excitation energy. This allows for a reduction in the driving voltage of the light-emitting device.

[0130] Note that the S1 level of the excited complex (S Ｅ ) and T1 level (T Ｅ ) are adjacent energy levels, so they readily undergo reverse intersystem crossing and possess TADF properties. Therefore, the excited complex has the function of converting the triplet excitation energy to the singlet excitation energy by upconversion (Root A in Figure 3B). ７ ). The singlet excitation energy possessed by the excited complex can be rapidly transferred to compound 332. (Route A in Figure 3B) ８ ). At this time, S Ｅ ≥S Ｇ It is preferable that this is the case. Route A ８ In this configuration, the excited complex acts as the energy donor, and compound 332 functions as the energy acceptor. Specifically, a tangent line is drawn at the short-wavelength tail of the fluorescence spectrum of the excited complex, and the energy at the wavelength of the extrapolation line is S. Ｅ Let S be the energy of the wavelength at the absorption edge of the absorption spectrum of compound 332. Ｇ When this happens, S Ｅ ≥S Ｇ It is preferable that this be the case.

[0131] Furthermore, in order to enhance the TADF properties, the T1 level of both compound 331 and compound 333, i.e., T Ｃ１ and T Ｃ３ However, T Ｅ It is preferable that the above conditions are met. As an indicator, it is preferable that the shortest wavelength emission peak wavelengths of the phosphorescence spectra of compound 331 and compound 333 are both less than or equal to the maximum emission peak wavelength of the excited complex. Alternatively, a tangent line is drawn at the short-wavelength tail of the fluorescence spectrum of the excited complex, and the energy of the wavelength of the extrapolation line is S. Ｅ Then, draw tangents to the short-wavelength tails of the phosphorescence spectra of compound 331 and compound 333, respectively, and calculate the T energy of the wavelengths of these extrapolations for each compound. Ｃ１ and T Ｃ３ When this happens, S Ｅ-T Ｃ１ ≤ 0.2 eV, and S Ｅ -T Ｃ３ It is preferable that the value is ≤0.2 eV.

[0132] The triplet excitation energy generated in the light-emitting layer 113 is taken via route A ６ and Route A ８ Through this process, energy is transferred to the S1 level of the guest material compound 332, thereby causing compound 332 to emit light. Therefore, by using a combination of materials that form an excitation complex in the light-emitting layer 113, the luminescence efficiency of the fluorescent light-emitting device can be increased. However, the triplet excitation energy generated in the light-emitting layer 113 is transferred to the T1 level of compound 332 via a pathway (Route A in Figure 3B). ９ ) can occur in competition. Such energy transfer (Route A ９ If this occurs, compound 332, which is a fluorescent material, cannot contribute the triplet excitation energy to light emission, and the light emission efficiency of the light-emitting device decreases.

[0133] Such energy transfer (Route A in Figure 3B) ９ In order to suppress this, as explained in Configuration Example 1 above, it is important that the distance between the excited complex formed by compound 331 and compound 333 and compound 332, and the distance between the excited complex and the luminescent phosphatid of compound 332 are of an appropriate length.

[0134] A compound according to one aspect of the present invention has a luminescent phose and a protecting group in part of its structure, and when it functions as an energy acceptor in the light-emitting layer 113, the protecting group has the function of maintaining an appropriate distance between the luminescent phose and other energy donors. Therefore, when a compound according to one aspect of the present invention is used as compound 332 in this configuration, even if the concentration of compound 332 is increased, the distance between the excited complex formed by compounds 331 and 333 and compound 332 can be maintained at an appropriate length, thereby suppressing energy transfer by the Dexter mechanism while increasing the energy transfer rate by the Förster mechanism. Therefore, by using a compound according to one aspect of the present invention as compound 332, the S1 level (S) of compound 332 can be increased from the excited complex. ＧEnergy transfer of triplet excitation energy to (Route A in Figure 3B) ６ and Route A ８ ) is more likely to occur, while the T1 level of compound 332 (T Ｇ Transfer of triplet excitation energy to (Route A) ９ This makes it less likely for energy transfer via the Dexter mechanism to occur, Route A ９ This method can increase the luminous efficiency of the light-emitting device while suppressing the decrease in luminous efficiency associated with energy transfer. Furthermore, it can improve the reliability of the light-emitting device.

[0135] In this specification, the above-mentioned Route A ６ Route A ７ , and Route A ８ This pathway is also referred to as ExSET (Exciplex-Singlet Energy Transfer) or ExEF (Exciplex-Enhanced Fluorescence). In other words, it indicates that in the light-emitting layer 113 described herein, excitation energy is transferred from the excitation complex to the fluorescent material.

[0136] <Example of Light-Emitting Layer Configuration 3> In this configuration example, the light-emitting layer 113 in the light-emitting device has compound 331, compound 332, and compound 333, and compound 331 and compound 333 are a combination that forms an excitation complex, and the case in which a fluorescent material is used as compound 332 which functions as a light-emitting substance (guest material) (case in which ExEF is used) is shown. Furthermore, this differs from the above configuration example 2 in that compound 333 is a phosphorescent material. Furthermore, it is preferable to use the compound 332 which is a fluorescent material in one aspect of the present invention. An example of the correlation of energy levels in the light-emitting layer 113 in this configuration example is shown in Figure 3C. Note that the notation and symbols shown in Figure 3C are the same as those in Figure 3B, so their description is omitted.

[0137] In this configuration example, a compound containing a heavy atom is used as one of the compounds forming the excited complex. Therefore, intersystem crossing between the singlet state and the triplet state is promoted. Thus, it is possible to form an excited complex that can transition from the triplet excited state to the singlet ground state (i.e., can exhibit phosphorescence). In this case, unlike ordinary excited complexes, the triplet excitation energy level (T) of the excited complex is Ｅ ) becomes the energy donor level, T Ｅ The singlet excitation energy level (S) of compound 332, which is a light-emitting material. Ｇ Preferably, it is ) or more. Specifically, a tangent is drawn at the short-wavelength tail of the emission spectrum of the excited complex using heavy atoms, and the energy of the wavelength of the extrapolation line is T Ｅ Let S be the energy of the wavelength at the absorption edge of the absorption spectrum of compound 332. Ｇ When that happens, T Ｅ ≥S Ｇ It is preferable that this be the case.

[0138] By using this kind of energy level correlation, the triplet excitation energy of the generated excited complex is the triplet excitation energy level (T) of the excited complex. Ｅ ) from the singlet excitation energy level of compound 332 (S Ｇ Energy can be transferred to the S1 level (S) of the excited complex. Ｅ ) and T1 level (T Ｅ Because these energy levels are adjacent to each other, it can be difficult to clearly distinguish between fluorescence and phosphorescence in the emission spectrum. In such cases, it may be possible to distinguish between fluorescence and phosphorescence by their emission lifetime.

[0139] Therefore, as shown in Figure 3C, in the light-emitting layer 113 of the light-emitting device shown in this example, the triplet excitation energy of the excited complex is Root A ８ Route (Route A in Figure 3C) ７ Without going through the path of S1 (S Ｇ Move to ). That is, Route A ６ and Route A ８Through this pathway, the triplet and singlet excitation energies can be transferred to the S1 level of the guest material. Note that Route A ８ In this configuration, the excited complex acts as an energy donor, and compound 332 functions as an energy acceptor. However, in the light-emitting layer 113 of the light-emitting device shown in this example, in addition to the above, there is also a pathway through which the triplet excitation energy of the excited complex moves to the T1 level of compound 332 (Route A in Figure 3C). ９ ) could also be in competition. Such energy transfer (Route A ９ When this occurs, the fluorescent material compound 332 cannot contribute the triplet excitation energy to light emission, thus reducing the luminescence efficiency of the light-emitting device.

[0140] Such energy transfer (Route A ９ In order to suppress this, as explained in the above configuration example 1, it is important that the distance between compound 331 and compound 332, and the distance between compound 331 and the luminescent phosphopectons of compound 332, are of an appropriate length.

[0141] A compound according to one aspect of the present invention has a luminescent phose and a protecting group in part of its structure, and when it functions as an energy acceptor in the light-emitting layer 113, the protecting group has the function of maintaining an appropriate distance between the luminescent phose and other energy donors. Therefore, when a compound according to one aspect of the present invention is used as compound 332 in this configuration, even if the concentration of compound 332 is increased, the distance between the excited complex formed by compounds 331 and 333 and compound 332 can be maintained at an appropriate length, thereby suppressing energy transfer by the Dexter mechanism while increasing the energy transfer rate by the Förster mechanism. Therefore, by using a compound according to one aspect of the present invention as compound 332, the S1 level (S) of compound 332 can be increased from the excited complex. Ｇ Energy transfer of triplet excitation energy to (Root A) ６ and Route A ８ ) is more likely to occur, while the T1 level of compound 332 (T Ｇ Transfer of triplet excitation energy to (Route A) ９This makes it less likely for energy transfer via the Dexter mechanism to occur, Route A ９ This method can increase the luminous efficiency of the light-emitting device while suppressing the decrease in luminous efficiency associated with energy transfer. Furthermore, it can improve the reliability of the light-emitting device.

[0142] <Example of Light-Emitting Layer Configuration 4> In this configuration example, the light-emitting layer 113 in the light-emitting device has three types of materials, namely compound 331, compound 332, and compound 333. Compounds 331 and 333 are a combination that forms an excitation complex, and the case in which a fluorescent material is used as compound 332, which functions as a light-emitting substance (guest material) (case where ExEF is used) is shown. Therefore, it is preferable to use the compound of one aspect of the present invention as compound 332, which is a fluorescent material. Note that this configuration example differs from the above configuration example 3 in that compound 333 is a material having TADF properties. Furthermore, an example of the correlation of energy levels in the light-emitting layer 113 in this configuration example is shown in Figure 4A. Note that the notation and symbols shown in Figure 4A are the same as those in Figure 3B, so their description is omitted.

[0143] In this configuration example, since compound 333 is a TADF material, compound 333, which does not form an excited complex, has the function of converting the triplet excitation energy to singlet excitation energy by upconversion (Route A in Figure 4A). １０ Therefore, the singlet excitation energy possessed by compound 333 is rapidly transferred to compound 332. (Route A in Figure 4A) １１ ). At this time, S Ｃ３ ≥S Ｇ It would be preferable if this were the case.

[0144] Therefore, in the light-emitting layer 113 of the light-emitting device shown in this configuration example, similar to the configuration example 3 above, Root A in Figure 4A ６ Route A ８ The triplet excitation energy is transferred to the guest material compound 332 via the above pathway, and route A in Figure 4A. １０ and Route A １１There is a pathway through which the triplet excitation energy moves to compound 332. In this way, the existence of multiple pathways through which the triplet excitation energy moves to the fluorescent material compound 332 makes it possible to further increase the luminescence efficiency. Route A ８ In this configuration, the excited complex acts as an energy donor, and compound 332 functions as an energy acceptor. Route A １１ In this configuration, compound 333 functions as an energy donor and compound 332 functions as an energy acceptor. However, in the light-emitting layer 113 of the light-emitting device shown in this example, in addition to the above, there is a pathway through which the triplet excitation energy of the excited complex moves to the T1 level of compound 332 (Route A in Figure 4A). ９ ) can also compete with such energy transfer (Route A ９ When this occurs, the fluorescent material compound 332 cannot contribute the triplet excitation energy to light emission, thus reducing the luminescence efficiency of the light-emitting device.

[0145] Such energy transfer (Route A ９ In order to suppress this, as explained in Configuration Example 1 above, it is important that the distance between the excited complex formed by compound 331 and compound 333 and compound 332, that is, the distance between the excited complex formed by compound 331 and compound 333 and the luminescent phosphatid of compound 332, is of an appropriate length.

[0146] A compound according to one aspect of the present invention has a luminescent phose and a protecting group in part of its structure, and when it functions as an energy acceptor in the light-emitting layer 113, the protecting group has the function of maintaining an appropriate distance between the luminescent phose and other energy donors. Therefore, when a compound according to one aspect of the present invention is used as compound 332 in this configuration, even if the concentration of compound 332 is increased, the distance between the excited complex formed by compounds 331 and 333 and compound 332 can be maintained at an appropriate length, thereby suppressing energy transfer by the Dexter mechanism while increasing the energy transfer rate by the Förster mechanism. Therefore, by using a compound according to one aspect of the present invention as compound 332, the S1 level (S) of compound 332 can be increased from the excited complex. ＧEnergy transfer of triplet excitation energy to (Root A) ６ and Route A ８ ) and the S1 level of compound 332 from the excited complex (S Ｇ Transfer of triplet excitation energy to (Route A) １０ and Route A １１ While both of the above are likely to occur, the T1 level of compound 332 (T Ｇ Transfer of triplet excitation energy to (Route A) ９ This makes it less likely for energy transfer via the Dexter mechanism to occur, Route A ９ This method can increase the luminous efficiency of the light-emitting device while suppressing the decrease in luminous efficiency associated with energy transfer. Furthermore, it can improve the reliability of the light-emitting device.

[0147] <Example of Light-Emitting Layer Configuration 5> In this configuration example, the light-emitting layer 113 in the light-emitting device has four types of materials, namely compound 331, compound 332, compound 333, and compound 334. Compound 333 has the function of converting triplet excitation energy into light emission, and is particularly a phosphorescent material. Compounds 331 and 334 are a combination that forms an excitation complex, and the case in which a fluorescent material is used as compound 332, which functions as a light-emitting material (guest material), is shown. Therefore, it is preferable to use the compound in one embodiment of the present invention as compound 332, which is a fluorescent material. An example of the correlation of energy levels in the light-emitting layer 113 in this configuration example is shown in Figure 4B. The notation and symbols in Figure 4B are the same as those shown in Figure 3B, and otherwise they are as shown below. ・S Ｃ４ : S1 level of compound 334, T Ｃ４ : T1 level of compound 334

[0148] In this example, compound 331 and compound 334 form an excited complex. Note that the S1 level of the excited complex (S Ｅ ) and the T1 level of the excited complex (T Ｅ ) are adjacent energy levels (Root A in Figure 4B) １２(See reference). However, if the excited complex formed by the two substances through the above pathway loses its excitation energy, the two substances will exist as their original separate substances.

[0149] Excitation energy levels of the excited complex (S Ｅ and T Ｅ ) is the S1 level (S Ｃ１ and S Ｃ４ Because this becomes lower, it becomes possible to form an excited state at a lower excitation energy. This allows for a reduction in the driving voltage of the light-emitting device.

[0150] Furthermore, since compound 333 is a phosphorescent material, intersystem crossing between the singlet and triplet states is permitted. Therefore, both the singlet and triplet excitation energies are rapidly transferred from the excited complex to compound 333 (Route A). １３ ). At this time, T Ｅ ≧T Ｃ３ It would be preferable if this were the case.

[0151] Furthermore, the triplet excitation energy of compound 333 is converted to the singlet excitation energy of compound 332 (Root A １４ ). At this time, as shown in Figure 4B, T Ｅ ≧T Ｃ３ ≥S Ｇ This is preferable because it allows for efficient energy transfer from compound 333 to compound 332. More specifically, a tangent line is drawn at the short-wavelength tail of the phosphorescence spectrum of compound 333, and the energy at the wavelength of the extrapolation line is T Ｃ３ Let S be the energy of the wavelength at the absorption edge of the absorption spectrum of compound 332. Ｇ When that happens, T Ｃ３ ≥S Ｇ It is preferable that this is the case. Note that Route A １４ In this configuration, compound 333 functions as an energy donor, and compound 332 functions as an energy acceptor.

[0152] In this example configuration, the combination of compound 331 and compound 334 may be any combination capable of forming an excited complex, but it is more preferable that one compound has hole-transporting properties and the other compound has electron-transporting properties.

[0153] Furthermore, as a combination of materials that efficiently forms an excited complex, it is preferable that the HOMO level of one of compound 331 and compound 334 is higher than the HOMO level of the other, and the LUMO level of one is higher than the LUMO level of the other.

[0154] Furthermore, the correlation between the energy levels of compound 331 and compound 334 is not limited to Figure 4B. That is, the singlet excitation energy level of compound 331 (S Ｃ１ ) is the singlet excitation energy level (S) of compound 334. Ｃ４ It may be higher or lower than ). Also, the triplet excitation energy level (T) of compound 331 Ｃ１ ) is the triplet excitation energy level (T) of compound 334. Ｃ４ It can be higher or lower than that.

[0155] Furthermore, in the light-emitting device of this configuration, it is preferable that compound 331 has a π-electron-deficient skeleton. This configuration lowers the LUMO level of compound 331, making it suitable for the formation of an excited complex.

[0156] Furthermore, in the light-emitting device of this configuration, it is preferable that compound 331 has a π-electron-rich skeleton. This configuration raises the HOMO level of compound 331, making it suitable for the formation of excited complexes.

[0157] A compound according to one aspect of the present invention has a luminescent phosphatid and a protecting group in part of its structure, and when it functions as an energy acceptor in the light-emitting layer 113, the protecting group has the function of maintaining an appropriate distance between the luminescent phosphatid and other energy donors. Therefore, when a compound according to one aspect of the present invention is used as compound 332 in this configuration, the distance between compound 333 and compound 332 can be maintained at an appropriate length. Therefore, by using a compound according to one aspect of the present invention as compound 332, the S1 level (S) of compound 332 can be maintained from compound 333. ＧEnergy transfer of triplet excitation energy to (Root A) １４ ) is more likely to occur, while the T1 level of compound 332 (T Ｇ Transfer of triplet excitation energy to (Route A) １５ This makes it less likely for energy transfer via the Dexter mechanism to occur, Route A １５ This method can increase the luminous efficiency of the light-emitting device while suppressing the decrease in luminous efficiency associated with energy transfer.

[0158] Furthermore, in this configuration example, by increasing the concentration of compound 332, which is the energy acceptor, it is possible to suppress energy transfer by the Dexter mechanism while increasing the energy transfer rate by the Förster mechanism. By increasing the energy transfer rate by the Förster mechanism, the excitation lifetime of the energy acceptor in the light-emitting layer is shortened, thereby improving the reliability of the light-emitting device. Specifically, the concentration of compound 332 in the light-emitting layer 113 is preferably 1 wt% to 50 wt%, more preferably 5 wt% to 30 wt%, and even more preferably 5 wt% to 20 wt%, relative to compound 333, which is the energy donor.

[0159] In the above configuration, it is preferable that the phosphorescent material used contains heavy atoms such as Ir, Pt, Os, Ru, and Pd. On the other hand, in this configuration example, since the phosphorescent material acts as an energy donor, the quantum yield can be high or low. That is, it is sufficient that the energy transfer from the triplet excitation energy level of the excited complex to the singlet excitation energy level of the guest material is an acceptable transition. The above-described configuration of an excited complex made of phosphorescent material or energy transfer from phosphorescent material to a guest material is a preferred configuration because the energy transfer from the triplet excitation energy level of the energy donor to the singlet excitation energy level of the guest material (energy acceptor) is an acceptable transition.

[0160] In this specification, the above-mentioned Route A １２ and Route A １３This pathway is also called ExTET (Exciplex-Triplet Energy Transfer). In other words, it indicates that in the light-emitting layer 113 of this specification, excitation energy is transferred from the excited complex to the compound 333.

[0161] <Example 6 of Light-Emitting Layer Configuration> In this configuration example, the light-emitting layer 113 in the light-emitting device has four types of materials, namely compound 331, compound 332, compound 333, and compound 334. Compound 333 has the function of converting triplet excitation energy into light emission, and is particularly a phosphorescent material. Compounds 331 and 334 are a combination that forms an excitation complex, and the case in which a fluorescent material is used as compound 332, which functions as a light-emitting material (guest material), is shown. Therefore, it is preferable to use the compound in one embodiment of the present invention as compound 332, which is a fluorescent material. Note that this configuration example differs from the above configuration example 5 in that compound 334 is a material that has TADF properties. An example of the correlation of energy levels in the light-emitting layer 113 in this configuration example is shown in Figure 4C. Note that the notation and symbols shown in Figure 4C are the same as those in Figures 3B and 4B, so their description is omitted.

[0162] Here, since compound 334 is a TADF material, compound 334, which does not form an excitation complex, has the function of converting the triplet excitation energy to singlet excitation energy by upconversion (Route A in Figure 4C). １６ Therefore, the singlet excitation energy of compound 334 is quickly transferred to compound 332 (Route A in Figure 4C). １７ ). At this time, S Ｃ４ ≥S Ｇ Preferably, this is the case. More specifically, a tangent is drawn at the short-wavelength tail of the fluorescence spectrum of compound 334, and the energy of the wavelength of the extrapolation line is S Ｃ４ Let S be the energy of the wavelength at the absorption edge of the absorption spectrum of compound 332. Ｇ When this happens, S Ｃ４ ≥S Ｇ It is preferable that this be the case.

[0163] Therefore, in the light-emitting layer 113 of the light-emitting device shown in this configuration example, similar to the configuration example 5 above, Route A in Figure 4C １２ Route A １３ , and Route A １４ The triplet excitation energy is transferred to the guest material compound 332 via the above pathway, and route A in Figure 4C. １６ and Route A １７ There is a pathway through which the triplet excitation energy moves to compound 332. In this way, the existence of multiple pathways through which the triplet excitation energy moves to the fluorescent material compound 332 makes it possible to further increase the luminescence efficiency. Route A １４ In this configuration, compound 333 functions as an energy donor and compound 332 functions as an energy acceptor. Also, Route A １７ In this configuration, compound 334 functions as an energy donor and compound 332 functions as an energy acceptor. However, in the light-emitting layer 113 of the light-emitting device shown in this example, in addition to the above, there is a path through which the triplet excitation energy of compound 333 moves to the T1 level of compound 332 (Route A in Figure 4C). １５ ) can also compete with such energy transfer (Route A １５ When this occurs, the fluorescent material compound 332 cannot contribute the triplet excitation energy to light emission, thus reducing the luminescence efficiency of the light-emitting device.

[0164] Such energy transfer (Route A １５ In order to suppress this, as explained in the above example configuration 1, it is important that the distance between compound 333 and compound 332, that is, the distance between compound 333 and the luminescent phosphopectons of compound 332, is of an appropriate length.

[0165] A compound according to one aspect of the present invention has a luminescent phose and a protecting group in part of its structure, and when it functions as an energy acceptor in the light-emitting layer 113, the protecting group has the function of maintaining an appropriate distance between the luminescent phose and other energy donors. Therefore, when a compound according to one aspect of the present invention is used as compound 332 in this configuration, even if the concentration of compound 332 is increased, the distance between compound 333 and compound 332 can be maintained at an appropriate length, and the energy transfer rate by the Förster mechanism can be increased while suppressing energy transfer by the Dexter mechanism. Therefore, by using a compound according to one aspect of the present invention as compound 332, the S1 level (S) of compound 332 can be increased from the excited complex. Ｇ Energy transfer of triplet excitation energy to (Root A) １２ and Route A １３ and Route A １４ ) and the S1 level of compound 332 from the excited complex (S Ｇ Transfer of triplet excitation energy to (Route A) １６ and Route A １７ While both of the above are likely to occur, the T1 level of compound 332 (T Ｇ Transfer of triplet excitation energy to (Route A) １５ This makes it less likely for energy transfer via the Dexter mechanism to occur, Route A １５ This method can increase the luminous efficiency of the light-emitting device while suppressing the decrease in luminous efficiency associated with energy transfer. Furthermore, it can improve the reliability of the light-emitting device.

[0166] <Example of Light-Emitting Layer Configuration 7> In this configuration example, the light-emitting layer 113 in the light-emitting device has compound 331, compound 332, and compound 333. Compound 333 has the function of converting triplet excitation energy into light emission, and is particularly a phosphorescent material. The case in which a fluorescent material is used as compound 332, which functions as a light-emitting material (guest material), is also shown. Therefore, it is preferable to use the compound in one embodiment of the present invention as compound 332, which is a fluorescent material. An example of the correlation of energy levels in the light-emitting layer 113 in this configuration example is shown in Figure 5A. The notation and symbols in Figure 5A are as follows: ・Comp(331): Compound 331 ・Comp(333): Compound 333 ・Guest(332): Compound 332 ・S Ｃ１ : S1 level of compound 331, T Ｃ１ : T1 level of compound 331, T Ｃ３ : T1 level of compound 333, T Ｇ : T1 level of compound 332, S Ｇ : S1 level of compound 332

[0167] In this configuration example, singlet and triplet excitons are generated mainly by carrier recombination in compound 331. Note that compound 333 is T Ｃ３ ≦T Ｃ１ By selecting a phosphorescent material having the following relationship, both the singlet excitation energy and triplet excitation energy generated in compound 331 can be converted to the T of compound 333. Ｃ３ It can be moved to the level (Figure 5A Route A) １８ ). Furthermore, some carriers can be recombined with compound 333.

[0168] Furthermore, it is preferable that the phosphorescent material used in the above configuration contains heavy atoms such as Ir, Pt, Os, Ru, and Pd. When the phosphorescent material is used as compound 333, the energy transfer from the triplet excitation energy level of the energy donor to the singlet excitation energy level of the guest material (energy acceptor) is an acceptable transition, which is preferable. Therefore, the triplet excitation energy of compound 333 is set to Root A １９ The S1 level of the guest material (S ＧIt can be moved to Route A. １９ In this case, compound 333 functions as an energy donor and compound 332 functions as an energy acceptor. Ｃ３ ≥S Ｇ This is preferable because the excitation energy of compound 333 is efficiently transferred to the singlet excited state of the guest material, compound 332. Specifically, a tangent line is drawn at the short-wavelength tail of the phosphorescence spectrum of compound 333, and the energy at the wavelength of the extrapolation line is T Ｃ３ Let S be the energy of the wavelength at the absorption edge of the absorption spectrum of compound 332. Ｇ When that happens, T Ｃ３ ≥S Ｇ It is preferable that this is the case. However, in the light-emitting layer 113 of the light-emitting device shown in this example, in addition to the above, there is a path through which the triplet excitation energy of compound 333 moves to the T1 level of compound 332 (Route A in Figure 5A). ２０ ) can also compete with such energy transfer (Route A ２０ When this occurs, the fluorescent material compound 332 cannot contribute the triplet excitation energy to light emission, thus reducing the luminescence efficiency of the light-emitting device.

[0169] Such energy transfer (Route A ２０ In order to suppress this, as explained in the above example configuration 1, it is important that the distance between compound 333 and compound 332, that is, the distance between compound 333 and the luminescent phosphopecton of compound 332, is of an appropriate length.

[0170] A compound according to one aspect of the present invention has a luminescent phosphodiolus and a protecting group in part of its structure, and when it functions as an energy acceptor in the light-emitting layer 113, the protecting group has the function of maintaining an appropriate distance between the luminescent phosphodiolus and other energy donors. Therefore, when a compound according to one aspect of the present invention is used as compound 332 in this configuration, even if the concentration of compound 332 is increased, the distance between compound 333 and compound 332 can be maintained at an appropriate length, and the energy transfer rate by the Förster mechanism can be increased while suppressing energy transfer by the Dexter mechanism. Therefore, by using a compound according to one aspect of the present invention as compound 332, the S1 level (S) of compound 332 can be increased from compound 333. Ｇ Energy transfer of triplet excitation energy to (Root A) １９ ) is more likely to occur, while the T1 level of compound 332 (T Ｇ Transfer of triplet excitation energy to (Route A) ２０ This makes it less likely for energy transfer via the Dexter mechanism to occur, Route A ２０ This method can increase the luminous efficiency of the light-emitting device while suppressing the decrease in luminous efficiency associated with energy transfer. Furthermore, it can improve the reliability of the light-emitting device.

[0171] <Example of Light-Emitting Layer Configuration 8> In this configuration example, the light-emitting layer 113 in the light-emitting device has compound 331, compound 332, and compound 333. Compound 333 has the function of converting triplet excitation energy into light emission, and is a material that is particularly TADF (Triple Attenuation Factor) material. The case in which a fluorescent material is used as compound 332, which functions as a light-emitting substance (guest material), is also shown. Therefore, it is preferable to use the compound in one embodiment of the present invention as compound 332, which is a fluorescent material. An example of the correlation of energy levels in the light-emitting layer 113 in this configuration example is shown in Figure 5B. The notation and symbols in Figure 5B are the same as those shown in Figure 5A, and otherwise they are as shown below. ・S Ｃ３ : S1 level of compound 333

[0172] In this configuration example, singlet and triplet excitons are generated mainly by carrier recombination in compound 331. Note that compound 333 is S Ｃ３ ≤S Ｃ１ And T Ｃ３ ≦T Ｃ１ By selecting a material with TADF properties that has the following relationship, both the singlet excitation energy and triplet excitation energy generated in compound 331 are transferred to the S of compound 333. Ｃ３ and T Ｃ３ It is possible to move to the next level (Figure 5B Route A) ２１ ). Furthermore, some carriers can be recombined with compound 333.

[0173] Furthermore, since compound 333 is a material with TADF properties, it has the function of converting triplet excitation energy to singlet excitation energy through upconversion (Figure 5B, Route A). ２２ ). Furthermore, the singlet excitation energy possessed by compound 333 can be rapidly transferred to compound 332. (Figure 5B Route A) ２３ ). At this time, S Ｃ３ ≥S Ｇ It is preferable that this is the case. More specifically, draw a tangent line at the short-wavelength tail of the fluorescence spectrum of compound 333, and set the energy of the wavelength of the extrapolation line to S Ｃ３ Let S be the energy of the wavelength at the absorption edge of the absorption spectrum of compound 332. Ｇ When this happens, S Ｃ３ ≥S Ｇ It is preferable that this be the case.

[0174] Therefore, in the light-emitting layer 113 of the light-emitting device shown in this configuration example, Root A in Figure 5B ２１、 Route A ２２ , and Route A ２３ By following this route, the triplet excitation energy generated in compound 333 can be converted into fluorescence emission in compound 332. Route A ２３In this configuration, compound 333 functions as an energy donor and compound 332 functions as an energy acceptor. However, in the light-emitting layer 113 of the light-emitting device shown in this example, in addition to the above, there is a path through which the triplet excitation energy of compound 333 moves to the T1 level of compound 332 (Route A in Figure 5B). ２４ ) can also compete with such energy transfer (Route A ２４ When this occurs, the fluorescent material compound 332 cannot contribute the triplet excitation energy to light emission, thus reducing the luminescence efficiency of the light-emitting device.

[0175] Such energy transfer (Route A ２４ In order to suppress this, as explained in the above example configuration 1, it is important that the distance between compound 333 and compound 332, that is, the distance between compound 333 and the luminescent phosphopectons of compound 332, is of an appropriate length.

[0176] A compound according to one aspect of the present invention has a luminescent phosphodiolus and a protecting group in part of its structure, and when it functions as an energy acceptor in the light-emitting layer 113, the protecting group has the function of maintaining an appropriate distance between the luminescent phosphodiolus and other energy donors. Therefore, when a compound according to one aspect of the present invention is used as compound 332 in this configuration, even if the concentration of compound 332 is increased, the distance between compound 333 and compound 332 can be maintained at an appropriate length, and the energy transfer rate by the Förster mechanism can be increased while suppressing energy transfer by the Dexter mechanism. Therefore, by using a compound according to one aspect of the present invention as compound 332, the S1 level (S) of compound 332 can be increased from compound 333. Ｇ Energy transfer of triplet excitation energy to (Root A) ２３ ) is more likely to occur, while the T1 level of compound 332 (T Ｇ Transfer of triplet excitation energy to (Route A) ２４ This makes it less likely for energy transfer (dexter mechanism) to occur, so Route A ２４ This method can increase the luminous efficiency of the light-emitting device while suppressing the decrease in luminous efficiency associated with energy transfer. Furthermore, it can improve the reliability of the light-emitting device.

[0177] <Energy Transfer Mechanisms> Here, we will explain the Förster mechanism and the Dexter mechanism. Here, we will explain the energy transfer process between the molecules of the first material (excited state) and the second material (ground state) regarding the transfer of excitation energy, but the same applies when one of them is an excited complex.

[0178] ≪Förster Mechanism≫ In the Förster mechanism, energy transfer does not require direct contact between molecules, but occurs through the resonance phenomenon of dipole vibrations between the first and second materials. Through the resonance phenomenon of dipole vibrations, the first material transfers energy to the second material, the excited first material returns to the ground state, and the ground state second material returns to the excited state. Note that the rate constant of the Förster mechanism is k. ｈ＊→ｇ This is shown in formula (1).

[0179]

[0180] In equation (1), ν represents the frequency, and f' ｈ (ν) represents the normalized emission spectrum of the first material (fluorescence spectrum when discussing energy transfer from the singlet excited state, phosphorescence spectrum when discussing energy transfer from the triplet excited state), and ε ｇ (ν) represents the molar extinction coefficient of the second material, N represents Avogadro's number, n represents the refractive index of the medium, R represents the intermolecular distance between the first and second materials, τ represents the measured excited state lifetime (fluorescence lifetime or phosphorescence lifetime), c represents the speed of light, φ represents the emission quantum yield (fluorescence quantum yield when discussing energy transfer from the singlet excited state, phosphorescence quantum yield when discussing energy transfer from the triplet excited state), and κ ２ This is a coefficient (from 0 to 4) that represents the orientation of the transition dipole moments of the first and second materials. Note that in the case of random orientation, κ ２ = 2 / 3.

[0181] ≪Dexter Mechanism≫ In the Dexter mechanism, the first and second materials approach the effective contact distance where their orbitals overlap, and energy transfer occurs through the exchange of electrons between the excited first material and the ground state second material. The rate constant of the Dexter mechanism is k. ｈ＊→ｇ This is shown in equation (2).

[0182]

[0183] In equation (2), h is Planck's constant, K is a constant with the dimension of energy, ν represents the frequency, and f' ｈ (ν) represents the normalized emission spectrum of the first material (fluorescence spectrum when discussing energy transfer from the singlet excited state, phosphorescence spectrum when discussing energy transfer from the triplet excited state), and ε' ｇ (ν) represents the normalized absorption spectrum of the second material, L represents the effective molecular radius, and R represents the intermolecular distance between the first and second materials.

[0184] Here, the energy transfer efficiency φ from the first material to the second material is... ＥＴ k is expressed by formula (3). ｒ k represents the rate constant of the luminescence process of the first material (fluorescence when discussing energy transfer from a singlet excited state, phosphorescence when discussing energy transfer from a triplet excited state), ｎ τ represents the rate constant for the non-luminescent process (thermal deactivation and intersystem crossing) of the second material, and τ represents the measured lifetime of the excited state of the first material.

[0185]

[0186] From equation (3), the energy transfer efficiency φ ＥＴ In order to increase the rate constant k of energy transfer, ｈ＊→ｇ Increase the other competing rate constants k ｒ +k ｎ It can be seen that the goal is to make (= 1 / τ) relatively small.

[0187] ≪Concepts for increasing energy transfer≫ First, let's consider energy transfer by the Förster mechanism. By substituting equation (1) into equation (3), we can eliminate τ. Therefore, in the case of the Förster mechanism, the energy transfer efficiency φ ＥＴ This does not depend on the lifetime τ of the excited state of the first material. Also, the energy transfer efficiency φ ＥＴ Therefore, it can be said that a higher emission quantum yield φ is better.

[0188] Furthermore, it is preferable that there is a large overlap between the emission spectrum of the first material and the absorption spectrum of the second material (the absorption corresponding to the transition from the singlet ground state to the singlet excited state). In addition, it is preferable that the molar extinction coefficient of the second material is also high. This means that the emission spectrum of the first material and the absorption band that appears at the longest wavelength of the second material overlap. Since a direct transition from the singlet ground state to the triplet excited state in the second material is forbidden, the molar extinction coefficient related to the triplet excited state in the second material is a negligible amount. For this reason, the energy transfer process from the excited state of the first material to the triplet excited state of the second material via the Förster mechanism can be ignored, and only the energy transfer process to the singlet excited state of the second material needs to be considered.

[0189] Furthermore, the energy transfer rate by the Förster mechanism is inversely proportional to the sixth power of the intermolecular distance R between the first and second materials, as shown in equation (1). Also, as mentioned above, when R is 1 nm or less, energy transfer by the Dexter mechanism becomes dominant. Therefore, in order to suppress energy transfer by the Dexter mechanism while increasing the energy transfer rate by the Förster mechanism, an intermolecular distance of 1 nm or more and 10 nm or less is preferable. Accordingly, since the protecting group described above does not need to be too bulky, the number of carbon atoms constituting the protecting group is preferably 3 or more and 10 or less.

[0190] Next, let's consider energy transfer via the Dexter mechanism. According to equation (2), the velocity constant k ｈ＊→ｇTo increase the efficiency, it is desirable to have a large overlap between the emission spectrum of the first material (fluorescence spectrum when discussing energy transfer from the singlet excited state, phosphorescence spectrum when discussing energy transfer from the triplet excited state) and the absorption spectrum of the second material (absorption corresponding to the transition from the singlet ground state to the singlet excited state). Therefore, the optimization of energy transfer efficiency is achieved by overlapping the emission spectrum of the first material with the absorption band that appears at the longest wavelength of the second material.

[0191] Furthermore, substituting equation (2) into equation (3) gives the energy transfer efficiency φ in the Dexter mechanism. ＥＴ It can be seen that this depends on τ. Since the Dexter mechanism is an energy transfer process based on electron exchange, energy transfer occurs from the triplet excited state of the first material to the triplet excited state of the second material, as well as from the singlet excited state of the first material to the singlet excited state of the second material.

[0192] In a light-emitting element according to one aspect of the present invention, since the second material is a fluorescent material, it is preferable that the energy transfer efficiency to the triplet excited state of the second material is low. That is, it is preferable that the energy transfer efficiency based on the Dexter mechanism from the first material to the second material is low, and that the energy transfer efficiency based on the Förster mechanism from the first material to the second material is high.

[0193] Furthermore, as already mentioned, the energy transfer efficiency in the Förster mechanism does not depend on the excited state lifetime τ of the first material. On the other hand, the energy transfer efficiency in the Dexter mechanism depends on the excited state lifetime τ of the first material, and in order to reduce the energy transfer efficiency in the Dexter mechanism, it is preferable that the excited state lifetime τ of the first material is short.

[0194] Therefore, one aspect of the present invention uses an excitation complex, a phosphorescent material, or a TADF material as the first material. These materials have the function of converting triplet excitation energy into light emission. Since the energy transfer efficiency of the Förster mechanism depends on the light emission quantum yield of the energy donor, a first material that can convert the energy of the triplet excited state into light emission, such as a phosphorescent material, an excitation complex, or a TADF material, can transfer its excitation energy to a second material via the Förster mechanism. On the other hand, the configuration of one aspect of the present invention promotes the reverse intersystem crossing from the triplet excited state to the singlet excited state of the first material (excitation complex or TADF material), thereby shortening the excitation lifetime τ of the triplet excited state of the first material. Furthermore, it promotes the transition from the triplet excited state to the singlet ground state of the first material (phosphorescent material or excitation complex using a phosphorescent material), thereby shortening the excitation lifetime τ of the triplet excited state of the first material. As a result, the energy transfer efficiency in the Dexter mechanism from the triplet excited state of the first material to the triplet excited state of the fluorescent material (second material) can be reduced.

[0195] Furthermore, in one embodiment of the present invention, a fluorescent material having a protecting group is used as the second material, as described above. Therefore, the intermolecular distance between the first material and the second material can be increased. Thus, in one embodiment of the present invention, by using a material having the function of converting triplet excitation energy into light emission as the first material and a fluorescent material having a protecting group as the second material, the energy transfer efficiency via the Dexter mechanism can be reduced. As a result, non-radiative deactivation of the triplet excitation energy in the light-emitting layer 113 can be suppressed, and a light-emitting element with high luminescence efficiency can be provided.

[0196] (Embodiment 3) In this embodiment, a light-emitting device according to one aspect of the present invention will be described in detail.

[0197] Figure 6A shows a diagram representing a light-emitting device according to one aspect of the present invention. The light-emitting device according to one aspect of the present invention has an organic compound layer 103 between a first electrode 101 formed on an insulating layer 1000 and a second electrode 102 facing the first electrode. The organic compound layer 103 has at least a light-emitting layer 113 and may further include other functional layers.

[0198] Figures 6A and 6B show an example comprising a hole injection layer 111, a hole transport layer 112, an electron transport layer 114, and an electron injection layer 115 (charge generation layer 116), but other functional layers such as an exciton blocking layer and an intermediate layer may also be included. Note that the hole transport layer 112 in contact with the light-emitting layer 113 may be specifically called the electron blocking layer, and the electron transport layer 114 in contact with the light-emitting layer may be specifically called the hole blocking layer.

[0199] In this embodiment, we will describe the case where the first electrode 101 functions as the anode and the second electrode 102 functions as the cathode, but this can also be reversed.

[0200] In one embodiment of the present invention, the organic compound layer 103 preferably contains at least one organic compound represented by general formula (G1) to general formula (G4) as described in Embodiment 1 and Embodiment 2, and the organic compound represented by general formula (G1) to general formula (G4) is preferably contained in the light-emitting layer 113.

[0201] Furthermore, it is preferable that the light-emitting layer 113 has a host material in addition to the organic compound represented by the general formulas (G1) to (G4). There may be multiple host materials, and it is preferable that the multiple host materials form an excitation complex. It is even more preferable that, in addition to the host material, it has a material (phosphorescent material or TADF material) that has the function of converting triplet excitation energy into light emission. The configuration of the light-emitting layer 113 has been described in detail in Embodiment 2, so a repetitive explanation will be omitted. Please refer to Embodiment 2.

[0202] In the light-emitting device of this embodiment, the first electrode 101 is an electrode including an anode, and the second electrode 102 is an electrode including a cathode. Although an example is shown in which the first electrode 101 is formed on the insulator 1000 side, a so-called reverse stacking configuration is also possible, in which the second electrode 102 is formed on the insulator 1000 side. In this case, the light-emitting device has a stacked structure in the following order from the insulator 1000 side: second electrode 102, electron injection layer 115, (electron transport layer 114), light-emitting layer 113, (hole transport layer 112, hole injection layer 111), and first electrode 101. In the case of a light-emitting device with such a reverse stacking structure, the relatively stable hole injection layer 111 becomes the surface, making it possible to make a more reliable light-emitting device.

[0203] Furthermore, the first electrode 101 and the second electrode 102 may be formed as a single-layer structure or a laminated structure. If they have a laminated structure, the layer in contact with the organic compound layer 103 functions as the anode or cathode. When the electrodes have a laminated structure, there are no constraints on the work function of the layers other than the layer in contact with the organic compound layer 103, and materials can be selected according to the required properties such as resistance, ease of processing, reflectivity, light transmittance, and stability.

[0204] The anode is preferably formed using a metal, alloy, conductive compound, or mixture thereof with a large work function (specifically, 4.0 eV or more). Specifically, examples include indium tin oxide (ITO), indium tin silicon oxide (ITSO) containing silicon or silicon oxide, indium zinc oxide, and indium oxide (IWZO) containing tungsten oxide and zinc oxide. These conductive metal oxide films are usually deposited by sputtering, but they may also be fabricated using methods such as the sol-gel method. An example of a fabrication method is to form indium zinc oxide by sputtering using a target to which 1 to 20 wt% zinc oxide is added to indium oxide. Furthermore, indium oxide containing tungsten oxide and zinc oxide (IWZO) can also be formed by sputtering using a target containing 0.5 to 5 wt% tungsten oxide and 0.1 to 1 wt% zinc oxide relative to indium oxide. Other materials that can be used as anodes include, for example, gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), titanium (Ti), aluminum (Al), or nitrides of metallic materials (e.g., titanium nitride). Alternatively, a layer of these materials can be used as the anode. For example, a film in which Al, Ti, and ITSO are laminated on Ti is preferred because it has good reflectivity, is highly efficient, and enables high resolution of several thousand ppi. Alternatively, graphene can also be used as a material for the anode. Furthermore, by using a composite material capable of forming the hole injection layer 111 (described later) as the layer in contact with the anode (typically the hole injection layer), it becomes possible to select the electrode material regardless of the work function.

[0205] The hole injection layer 111 is provided in contact with the anode and has the function of facilitating the injection of holes into the organic compound layer 103. The hole injection layer 111 contains phthalocyanine (abbreviated as H ２It can be formed from phthalocyanine compounds or complex compounds such as Pc, copper phthalocyanine (abbreviated as CuPc), aromatic amine compounds such as 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviated as DPAB), 4,4'-bis(N-{4-[N'-(3-methylphenyl)-N'-phenylamino]phenyl}-N-phenylamino)biphenyl (abbreviated as DNTPD), or polymers such as poly(3,4-ethylenedioxythiophene) / polystyrene sulfonic acid (abbreviated as PEDOT / PSS).

[0206] Furthermore, the hole injection layer 111 may be formed from a substance having electron-accepting properties. Examples of substances having electron-accepting properties include organic compounds having electron-withdrawing groups (halogen groups, cyano groups, etc.), such as 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviated as F4-TCNQ), chloranil, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviated as HAT-CN), 1,3,4,5,7,8-hexafluorotetracyano-naphthoquinodimethane (abbreviated as F6-TCNNQ), and 2-(7-dicyanomethylene-1,3,4,5,6,8,9,10-octafluoro-7H-pyrene-2-ylidene)malononitrile. In particular, compounds in which an electron-withdrawing group is bonded to a condensed aromatic ring having multiple complex atoms, such as HAT-CN, are thermally stable and therefore preferred. Furthermore, [3]radialene derivatives having an electron-withdrawing group (especially halogen groups such as fluoro groups, cyano groups, etc.) are preferred because they have very high electron-accepting properties. Specific examples include α,α',α''-1,2,3-cyclopropanetriylidenates [4-cyano-2,3,5,6-tetrafluorobenzeneacetonitrile], α,α',α''-1,2,3-cyclopropanetriylidenates [2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)benzeneacetonitrile], and α,α',α''-1,2,3-cyclopropanetriylidenates [2,3,4,5,6-pentafluorobenzeneacetonitrile]. In addition to the organic compounds mentioned above, other acceptor substances that can be used include transition metal oxides such as molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, and manganese oxide. Furthermore, phthalocyanine (abbreviation: H) can also be used. ２The hole injection layer 111 can also be formed by phthalocyanine compounds or complex compounds such as Pc, copper phthalocyanine (abbreviated as CuPc), aromatic amine compounds such as 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviated as DPAB), 4,4'-bis(N-{4-[N'-(3-methylphenyl)-N'-phenylamino]phenyl}-N-phenylamino)biphenyl (abbreviated as DNTPD), or polymers such as poly(3,4-ethylenedioxythiophene) / polystyrene sulfonic acid (abbreviated as PEDOT / PSS). Accepting substances can extract electrons from adjacent hole transport layers (or hole transport materials) by applying an electric field.

[0207] Furthermore, it is preferable that the hole injection layer 111 be formed from a composite material containing the acceptor material and the hole transporting material.

[0208] Various organic compounds can be used as hole-transporting substances in composite materials, including aromatic amine compounds, heteroaromatic compounds, aromatic hydrocarbons, and polymer compounds (oligomers, dendrimers, polymers, etc.). −６ cm ２ It is preferable that the substance has a hole mobility of 1 / Vs or higher. The hole-transporting substance used in the composite material is preferably a compound having a condensed aromatic hydrocarbon ring or a π-electron-rich heteroaromatic ring. As the condensed aromatic hydrocarbon ring, anthracene rings, naphthalene rings, etc. are preferred. As the π-electron-rich heteroaromatic ring, a condensed aromatic ring containing at least one of a pyrrole skeleton, a furan skeleton, or a thiophene skeleton is preferred, and specifically, a carbazole ring, a dibenzothiophene ring, or a ring in which an aromatic ring or heteroaromatic ring is further condensed thereon is preferred.

[0209] Such hole-transporting materials more preferably have at least one of the following skeletons: a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and an anthracene skeleton. In particular, they may be aromatic amines having substituents including a dibenzofuran ring or a dibenzothiophene ring, aromatic monoamines having a naphthalene ring, or aromatic monoamines in which a 9-fluorenyl group is bonded to the nitrogen of the amine via an arylene group. Furthermore, it is preferable that these hole-transporting materials have an N,N-bis(4-biphenyl)amino group, as this allows for the creation of light-emitting devices with a good lifetime.

[0210] Examples of substances possessing hole transport properties as described above include N-(4-biphenyl)-6,N-diphenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BnfABP), N,N-bis(4-biphenyl)-6-phenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf), 4,4'-bis(6-phenylbenzo[b]naphtho[1,2-d]furan-8-yl)-4''-phenyltriphenylamine (abbreviation: BnfBB1BP), N,N-bis(4-biphenyl)benzo[b]naphtho[ 1,2-d]furan-6-amine (abbreviation: BBABnf(6)), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf(8)), N,N-bis(4-biphenyl)benzo[b]naphtho[2,3-d]furan-4-amine (abbreviation: BBABnf(II)(4)), N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP), N-[4-(dibenzothiophen-4-yl)phenyl]-N-phenyl-4-biphen Luamine (abbreviation: ThBA1BP), 4-(2-naphthyl)-4',4''-diphenyltriphenylamine (abbreviation: BBAβNB), 4-[4-(2-naphthyl)phenyl]-4',4''-diphenyltriphenylamine (abbreviation: BBAβNBi), 4,4'-diphenyl-4''-([2,1'-binaphthyl]-6-yl)triphenylamine (abbreviation: BBAαNβNB), 4,4'-diphenyl-4''-([2,1'-binaphthyl]-7-yl)triphenylamine (abbreviation: BBAαNβNB-03), 4,4'-diphenyl -4''-(7-phenyl)naphthyl-2-yltriphenylamine (abbreviation: BBAPβNB-03), 4,4'-diphenyl-4''-([2,2'-binaphthyl]-6-yl)triphenylamine (abbreviation: BBA(βN2)B), 4,4'-diphenyl-4''-([2,2'-binaphthyl]-7-yl)triphenylamine (abbreviation: BBA(βN2)B-03), 4,4'-diphenyl-4''-([1,2'-binaphthyl]-4-yl)triphenylamine (abbreviation: BBAβNαNB), 4,4'-diphenyl-4''-([1,2'-binaphthyl]-5-yl)triphenylamine (abbreviation: BBAβNαNB-02), 4-(4-biphenylyl)-4'-(2-naphthyl)-4''-phenyltriphenylamine (abbreviation: TPBiAβNB), 4-(3-biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4''-phenyltriphenylamine (abbreviation: mTPBiAβNBi), 4-(4-biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4''-phenyl Triphenylamine (abbreviation: TPBiAβNBi), 4-phenyl-4'-(1-naphthyl)triphenylamine (abbreviation: αNBA1BP), 4,4'-bis(1-naphthyl)triphenylamine (abbreviation: αNBB1BP), 4,4'-diphenyl-4''-[4'-(carbazole-9-yl)biphenyl-4-yl]triphenylamine (abbreviation: YGTBi1BP), 4'-[4-(3-phenyl-9H-carbazole-9-yl)phenyl]tris (Biphenyl-4-yl)amine (abbreviation: YGTBi1BP-02), 4-[4'-(carbazole-9-yl)biphenyl-4-yl]-4'-(2-naphthyl)-4''-phenyltriphenylamine (abbreviation: YGTBiβNB), N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-N-[4-(1-naphthyl)phenyl]-9,9'-spirobio[9H-fluorene]-2-amine (abbreviation: PCBNBSF), N,N-bis( Biphenyl-4-yl)-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: BBASF), N,N-bis(biphenyl-4-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviation: BBASF(4)), N-(biphenyl-2-yl)-N-(9,9-dimethyl-9H-fluorene-2-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviation: oFBiSF), N-(biphenyl-4-yl)-N-(9,9-dimethyl-9H-fluoren-2-yl)dibenzofuran-4-amine (abbreviation: FrBiF), N-[4-(1-naphthyl)phenyl]-N-[3-(6-phenyldibenzofuran-4-yl)phenyl]-1-naphthylamine (abbreviation: mPDBfBNBN), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4'-[4-(9-phenylfluoren-9- [Iyl)phenyl]triphenylamine (abbreviation: BPAFLBi), 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazole-3-yl) Triphenylamine (abbreviation: PCBNBB), N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9'-spirobio[9H-fluorene]-2-amine (abbreviation: PCBASF), N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9-dimethyl-9H-fluorene-2-amine (abbreviation: PCBBiF), N,N-bis(9,9-dimethyl-9H-fluorene-2-yl)-9,9'-spirobio[9H-fluorene-4-amine), N,N-bis( 9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-3-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-2-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-1-amine, 9-[3-(triphenylsilyl)phenyl]-3,9'-bi-9H-carbazole (abbreviation: PSiCzCz), 9'-[3-(triphenylsilyl)phenyl]-9'H-9,3':6',Examples include 9''-Telcarbazole (abbreviated as PSiCzGI).

[0211] Furthermore, other aromatic amine compounds that possess hole-transporting properties can also be used, such as N,N'-di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviated as DTDPPA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviated as DPAB), 4,4'-bis(N-{4-[N'-(3-methylphenyl)-N'-phenylamino]phenyl}-N-phenylamino)biphenyl (abbreviated as DNTPD), and 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviated as DPA3B).

[0212] By forming the hole injection layer 111, the hole injection performance is improved, and a light-emitting device with a low driving voltage can be obtained.

[0213] Furthermore, among substances with acceptor properties, organic compounds with acceptor properties are easy to use because they are readily deposited and easy to form films.

[0214] The hole transport layer 112 is formed by including a material that has hole transport properties. The material that has hole transport properties is 1 × 10 −６ cm ２ It is preferable that the hole mobility is greater than or equal to / Vs. The hole transport layer 112 may be a single layer or a laminated layer.

[0215] The above-mentioned hole-transporting substances include 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviated as NPB), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-4,4'-diaminobiphenyl (abbreviated as TPD), N,N'-bis(9,9'-spirobi[9H-fluoren]-2-yl)-N,N'-diphenyl-4,4'-diaminobiphenyl (abbreviated as BSPB), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviated as BPAFLP), and 4-phenyl-3'- (9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''-(9-phenyl-9 Compounds having an aromatic amine skeleton such as H-carbazole-3-yl)triphenylamine (abbreviation: PCBNBB), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9'-spirobi[9H-fluoren]-2-amine (abbreviation: PCBASF), 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-di(N-carbazolyl) Basolyl)biphenyl (abbreviated as CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviated as CzTP), 9,9'-diphenyl-9H,9'H-3,3'-bicarbazole (abbreviated as PCCP), 9,9'-bis(biphenyl-4-yl)-3,3'-bi-9H-carbazole (abbreviated as BisBPCz), 9,9'-bis(biphenyl-3-yl)-3,3'-bi-9H-carbazole (abbreviated as BismBPCz), 9-(biphenyl-3-yl)-9'-(biphenyl-4-yl)-9H,9'H-3,3'-bicarbazole (abbreviation: mBPCCBP), 9-(2-naphthyl)-9'-phenyl-3,3'-bi-9H-carbazole (abbreviation: βNCCP), 9-(3-biphenyl)-9'-(2-naphthyl)-3,3'-bi-9H-carbazole (abbreviation: βNCCmBP), 9-(4-biphenyl)-9'-(2-naphthyl)-3,3'-bi-9H-carbazole (abbreviation: βNCBP), 9,9'-di-2-naphthyl-3,3'-9H,9'H-bicarbazole (abbreviation: BisβNCz), 9-(2-naphthyl)-9'-[1,1' :4',1"-terphenyl]-3-yl-3,3'-9H,9'H-bicarbazole,9-(2-naphthyl)-9'-[1,1':3',1"-terphenyl]-3-yl-3,3'-9H,9'H-bicarbazole,9-(2-naphthyl)-9'-[1,1':3',1"-terphenyl]-5'-yl-3,3'-9H,9'H-bicarbazole,9-(2-naphthyl)-9'-[1,1':4',1"-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole,9-(2-naphthyl)-9'-[1,1':3' ,1"-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-(triphenylene-2-yl)-3,3'-9H,9'H-bicarbazole, 9-phenyl-9'-(triphenylene-2-yl)-3,3'-9H,9'H-bicarbazole (abbreviation: PCCzTp), 9,9'-bis(triphenylene-2-yl)-3,3'-9H,9'H-bicarbazole, 9-(4-biphenyl)-9'-(triphenylene-2-yl)-3,3'-9H,9'H-bicarbazole, 9-(tri Compounds having a carbazole skeleton such as phenylen-2-yl)-9'-[1,1':3',1''-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-1-amine, 9-[3-(triphenylsilyl)phenyl]-3,9'-bi-9H-carbazole (abbreviation: PSiCzCz), 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), 2,Examples include compounds having a thiophene skeleton such as 8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviated as DBTFLP-III) and 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviated as DBTFLP-IV), and compounds having a furan skeleton such as 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviated as DBF3P-II) and 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviated as mmDBFFLBi-II). Among the above, compounds having an aromatic amine skeleton and compounds having a carbazole skeleton are preferred because they have good reliability, high hole transportability, and contribute to reducing the driving voltage. Furthermore, the organic compounds listed as hole-transporting substances used in the composite material of the hole injection layer 111 can also be suitably used as materials constituting the hole transport layer 112. It is even more preferable to use organic compounds having an amine skeleton and a fluorene skeleton. Moreover, organic compounds having an amine skeleton and a fluorene skeleton are preferable because they have good reliability and high hole transport properties, thereby reducing the power consumption of the light-emitting device.

[0216] The light-emitting layer 113 is a layer containing a light-emitting central material. It is also preferable that it contains a host material.

[0217] The luminescent central material may be a fluorescent material, a phosphorescent material, a thermally activated delayed fluorescence (TADF) material, or any other luminescent material.

[0218] Examples of materials that can be used as fluorescent materials in the light-emitting layer include the following. Other fluorescent materials can also be used.

[0219] 5,6-bis[4-(10-phenyl-9-antryl)phenyl]-2,2'-bipyridine (abbreviation: PAPP2BPy), 5,6-bis[4'-(10-phenyl-9-antryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2BPy), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]pyren-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: 1,6mMemFLPAPrn), N,N'-bis[4-(9H-carbazole-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazole-9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), 4-(9H-carbazole-9-yl)-4'-(9,10-diphenyl-2-anthryl)triphenylamine (abbreviation: 2YGAAPPA), N,9-diphenyl-N-[4-( 10-phenyl-9-anthryl)phenyl]-9H-carbazole-3-amine (abbreviation: PCAPA), perylene, 2,5,8,11-tetra-tert-butylperylene (abbreviation: TBP), 4-(10-phenyl-9-anthryl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBAPA), N,N''-(2-tert-butylanthracene-9,10-diyldi-4,1-phenylene)bis(N,N',N'-triphenyl-1,4-phenylenediamine) (abbreviation: DPABPA), N,9 -Diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazole-3-amine (abbreviation: 2PCAPPA), N-[4-(9,10-diphenyl-2-anthryl)phenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPPA), N,N,N',N',N'',N'',N''',N'''-octaphenyldibenzo[g,p]chrysene-2,7,10,15-tetraamine (abbreviation: DBC1), coumarin 30, N-(9,10-diphenyl-2-anthryl)-N,9-diphenyl-9H-carbazole-3-amine (abbreviation: 2PCAPA), N-[9,10-bis(biphenyl-2-yl)-2-anthryl]-N,9-diphenyl-9H-carbazole-3-amine (abbreviation: 2PCABPhA), N-(9,10-diphenyl-2-anthryl)-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPA), N-[9,10-bis(biphenyl-2-yl)-2-anthryl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPABPhA) 9,10-bis(biphenyl-2-yl)-N-[4-(9H-carbazole-9-yl)phenyl]-N-phenylanthracene-2-amine (abbreviation: 2YGABPhA), N,N,9-triphenylanthracene-9-amine (abbreviation: DPhAPhA), coumarin 545T, N,N'-diphenylquinacridone (abbreviation: DPQd), rubren, 5,12-bis(biphenyl-4-yl)-6,11-diphenyltetracene (abbreviation: BPT), 2-(2-{2-[4-(dimethylamino)phenyl]ethenyl}-6-methyl-4H-pyra N-4-ylidene)propanedinitrile (abbreviation: DCM1), 2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinoridine-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCM2), N,N,N',N'-tetrakis(4-methylphenyl)tetracene-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-N,N,N',N'-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluorantene-3,10-diamine (abbreviation) Name: p-mPhAFD), 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinoridine-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTI), 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinoridine-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTB), 2-(2,6-bis{2-[4-(dimethylamino)phenyl]ethenyl}-4H-pyran-4-ylidene)propanedinitrile (abbreviation: BisDCM), 2-{2,6-bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinoridine-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: BisDCJTM), N,N'-diphenyl-N,N'-(1,6-pyrene-diyl)bis[(6-phenylbenzo[b]naph Examples include to[1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-03), N,N'-diphenyl-N,N'-bis(9-phenyl-9H-carbazole-2-yl)naphtho[2,3-b;6,7-b']bisbenzofuran-3,10-diamine (abbreviation: 3,10PCA2Nbf(IV)-02), and 3,10-bis[N-(dibenzofuran-3-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10FrA2Nbf(IV)-02). In particular, condensed aromatic diamine compounds, such as pyrenediamine compounds like 1,6FLPAPrn, 1,6mMemFLPAPrn, and 1,6BnfAPPrn-03, are preferred because they exhibit high hole-trapping properties and excellent luminescence efficiency or reliability.

[0220] Also, 5,9-diphenyl-5H,9H-[1,4]benzazaborino[2,3,4-kl]phenazaborine (abbreviation: DABNA-1), 9-(biphenyl-3-yl)-N,N,5,11-tetraphenyl-5H,9H-[1,4]benzazaborino[2,3,4-kl]phenazaborin-3-amine (abbreviation: DABNA-2), 2,12-di(tert-butyl)-5,9-di(4-tert-butylphenyl)-N,N-diphenyl-5H,9H-[1,4]benzazaborino[2,3,4-kl]phenazaborin-7-amine (abbreviation: DPhA-tBu4DABNA), 2,12-di(tert-butyl)-N,N,5,9-tetra(4-tert-butylphenyl)-5H,9H-[1,4]benzazaborino[2,3,4-kl]phenazaborin-7-amine (abbreviation: tBuDPhA-tBu4DABNA), 2,12-di(tert-butyl)-5,9-di(4-tert-butylphenyl)-7-methyl-5H,9H-[1,4]benzazaborino[2,3,4-kl]phenazaborine (abbreviation: Me-tBu4DABNA), N ７ , N ７ , N １３ , N １３ , 5,9,11,15-octaphenyl-5H,9H,11H,15H-[1,4]benzazaborino[2,3,4-kl][1,4]benzazaborino[4',3',2':4,5][1,4]benzazaborino[3,2-b]phenazaborine-7,13-diamine (abbreviation: ν-DABNA), 2-(4-tert-butylphenyl)benzo[5,6]indolo[3,2,1-jk]benzo[b]carbazole (abbreviation: tBuPBibc), and other condensed heteroaromatic compounds containing nitrogen and boron, particularly compounds having a diaza-boranaphtho-anthracene skeleton, can be suitably used because they can obtain blue light emission with a narrow emission spectrum width and good color purity.

[0221] In addition to these, 9,10,11-tris[3,6-bis(1,1-dimethylethyl)-9H-carbazolyl-9-yl]-2,5,15,18-tetrakis(1,1-dimethylethyl)indoro[3,2,1-de]indoro[3',2',1':8,1][1,4]benzazaborino[2,3,4-kl]phenazavolin (abbreviation: BBCz-G), 9,11-bis[ Compounds having an indole skeleton, such as 3,6-bis(1,1-dimethylethyl)-9H-carbazolyl-9-yl]-2,5,15,18-tetrakis(1,1-dimethylethyl)indro[3,2,1-de]indro[3',2',1':8,1][1,4]benzazavolino[2,3,4-kl]phenazavolin (abbreviation: BBCz-Y), can be suitably used.

[0222] In the light-emitting layer, suitable phosphorescent materials that can be used as the light-emitting central material include metal complexes, particularly iridium complexes or platinum complexes, and examples include the following.

[0223] Tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazole-3-yl-κN2]phenyl-κC}Iridium(III) (Abbreviation: [Ir(mpptz-dmp) ３ ]), Tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazolato) iridium (III) (abbreviation: [Ir(Mptz) ３ ]), organometallic iridium complexes having a 4H-triazole skeleton such as 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-triazolato) Iridium(III) (abbreviation: [Ir(Prptz1-Me) ３ ]) an organometallic iridium complex having a 1H-triazole skeleton, such as fac-tris[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]iridium(III) (abbreviation: [Ir(iPrpim) ３), tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(III) (abbreviation: [Ir(dmpimpt-Me) ３ ), organometallic iridium complexes having an imidazole skeleton such as tris(2-{1-[2,6-bis(1-methylethyl)phenyl]-1H-imidazol-2-yl-κN3}-4-cyanophenyl-κC)iridium(III) (abbreviation: CNIr), tris[(6-tert-butyl-3-phenyl-2H-imidazo[4,5-b]pyrazin-1-yl-κC2)phenyl-κC]iridium(III) (abbreviation: [Ir(cb) ３ ), organometallic complexes having a benzimidazoliden skeleton such as [Ir(cb)]), bis[2-(4',6'-difluorophenyl)pyridinato-N,C ２’ iridium(III) tetrakis(1-pyrazolyl)borate (abbreviation: FIr6), bis[2-(4',6'-difluorophenyl)pyridinato-N,C ２’ iridium(III) picolinate (abbreviation: FIrpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinato-N,C ２’}iridium(III) picolinate (abbreviation: [Ir(CF ３ ppy) ２ (pic)]), organometallic iridium complexes having a phenylpyridine derivative having an electron-withdrawing group such as bis[2-(4',6'-difluorophenyl)pyridinato-N,C ２’ iridium(III) acetylacetonate (abbreviation: FIracac) as a ligand, platinum complexes such as (2-{3-[3-(3,5-di-tert-butylphenyl)benzimidazol-1-yl-2-ylidene-κC2]phenoxy-κC2}-9-(4-tert-butyl-2-pyridinyl-κN)carbazole-2,1-diyl-κC1)platinum(II) (abbreviation: PtON-TBBi), and the like. These are compounds that exhibit blue-phase phosphorescent emission and are compounds having an emission peak in the wavelength range from 450 nm to 520 nm. In addition, compounds in which some of the hydrogens of these compounds are replaced with deuterium can also be used.

[0224] Also, tris(4-methyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm) ３ ]), Tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm) ３ ]), (acetylacetonato)bis(6-methyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm) ２ (acac)), (acetylacetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm) ２ (acac)), (acetylacetonate)bis[6-(2-norbornyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(nbppm) ２ (acac)), (acetylacetonato)bis[5-methyl-6-(2-methylphenyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(mpmpppm) ２ (acac)), (acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III) (abbreviation: [Ir(dppm) ２ Organometallic iridium complexes having a pyrimidine skeleton such as (acac) (acetylacetonato)bis(3,5-dimethyl-2-phenylpyradinato)iridium(III) (abbreviation: [Ir(mppr-Me) ２ (acac)), (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyradinato)iridium(III) (abbreviation: [Ir(mppr-iPr) ２ Organometallic iridium complexes having a pyrazine skeleton such as (acac), Tris(2-phenylpyridinato-N,C) ２’ Iridium (III) (abbreviation: [Ir(ppy) ３ ]), bis(2-phenylpyridinate-N,C ２’ ) Iridium(III) acetylacetonate (abbreviation: [Ir(ppy) ２ (acac)), bis(benzo[h]quinolinate)iridium(III)acetylacetonate (abbreviation: [Ir(bzq) ２(acac)), Tris(benzo[h]quinolinate) Iridium(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 (acac)]), [2-d3-methyl-8-(2-pyridinyl-κN)benzofl[2,3-b]pyridine-κC]bis[2-(5-d ３ [Methyl-2-pyridinyl-κN2)phenyl-κC]iridium(III) (abbreviation: Ir(5mppy-d) ３ ) ２ (mbfpypy-d ３ )), {2-(methyl-d ３ )-8-[4-(1-methylethyl-1-d)-2-pyridinyl-κN]benzofl[2,3-b]pyridin-7-yl-κC]bis{5-(methyl-d ３ )-2-[5-(methyl-d ３ )-2-pyridinyl-κN]phenyl-κC}iridium(III) (abbreviation: Ir(5mtpy-d6) ２ (mbfpypy-iPr-d ４ )), [2-(methyl-d3)-8-(2-pyridinyl-κN)benzofl[2,3-b]pyridine-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: Ir(ppy) ２ (mbfpypy-d ３ )), [2-(4-methyl-5-phenyl-2-pyridinyl-κN)phenyl-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: Ir(ppy) ２ (mdppy)), [2-(4-d ３ [methyl-5-phenyl-2-pyridinyl-κN2)phenyl-κC]bis[2-(5-d ３ [Iridium (III) (abbreviation: [Ir(5mppy-d)])(methyl-2-pyridinyl-κN2)phenyl-κC) ３ )2(mdppy-d ３) )]), [2-methyl-8-(2-pyridinyl-κN)benzofl[2,3-b]pyridine-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: [Ir(ppy) ２ (mbfpypy))]), [2-(4-methyl-5-phenyl-2-pyridinyl-κN)phenyl-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium (abbreviation: [Ir(ppy) ２ (mdppy)]), Tris{2-[5-(methyl-d3)-4-phenyl-2-pyridinyl-κN]phenyl-κC}Iridium(III) (abbreviation: Ir(5m4dppy-d ３ ) ３ In addition to organometallic iridium complexes having a pyridine skeleton such as (2-{1-(5-tert-butylbiphenyl-2-yl)-4-[3-tert-butyl-5-(4-phenyl-2-pyridinyl-κN)phenyl-κC6]-2-benzimidazolyl-κN3}-4,6-di-tert-butylphenolate-κO)platinum(II) (abbreviation: Pt(tBudpppymmtBubiz-tBubp)), [2-(4-(3,5-di-te Organometallic platinum complexes such as rt-butylphenyl)-6-{3-[4-(5'-tert-butyl[1,1':3',1''-terphenyl]-2'-yl)-2-pyridinyl-κN]phenyl-κC2}-2-pyridinyl-κN)phenolato-κO]platinum(II) (abbreviation: Pt(4tButpppypyp-mmtBup)), tris(acetylacetonato)(monophenanthroline)terbium(III) (abbreviation: [Tb(acac) ３ Examples include rare earth metal complexes such as (Phen)). These are compounds that exhibit phosphorescence with a green hue and have emission peaks in the wavelength range of 500 nm to 600 nm. Organometallic iridium complexes having a pyrimidine skeleton are particularly preferred due to their outstanding reliability and luminescence efficiency. Compounds in which some of the hydrogen atoms are replaced with deuterium can also be used.

[0225] Also, (diisobutyrylmethanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(III) (abbreviation: [Ir(5mdppm)２ (dibm)]), bis[4,6-bis(3-methylphenyl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(5mdppm) ２ (dpm)]), bis[4,6-di(naphthalene-1-yl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(d1npm) ２ Organometallic iridium complexes having a pyrimidine skeleton such as (dpm)]), (acetylacetonato)bis(2,3,5-triphenylpyradinato)iridium(III) (abbreviation: [Ir(tppr) ２ (acac)), bis(2,3,5-triphenylpyrazinato)(dipivaloylmethanato) iridium(III) (abbreviation: [Ir(tppr) ２ (dpm)]), (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviation: [Ir(Fdpq) ２ Organometallic iridium complexes having a pyrazine skeleton such as (acac), 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 (acac)), (3,7-diethyl-4,6-nonanedionato-κO4,κO6)bis[2,4-dimethyl-6-[7-(1-methylethyl)-1-isoquinolinyl-κN]phenyl-κC]iridium(III), (3,7-diethyl-4,6-nonanedionato-κO4,κO6)bis[2,4-dimethyl-6-[5-(1-methylethyl)-2-quinolinyl-κN]phenyl In addition to organometallic iridium complexes with a pyridine skeleton such as [-κC]iridium(III), there are platinum complexes such as 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum(II) (abbreviation: PtOEP), and tris(1,3-diphenyl-1,3-propanedionato)(monophenanthroline)europium(III) (abbreviation: [Eu(DBM)] ３(Phen)]), Tris[1-(2-tenoyl)-3,3,3-trifluoroacetonate](monophenanthroline) europium(III) (abbreviation: [Eu(TTA) ３ Examples include rare earth metal complexes such as (Phen)). These compounds exhibit phosphorescent emission with a red hue and have emission peaks in the wavelength range of 600 nm to 700 nm. In addition, organometallic iridium complexes with a pyrazine skeleton yield red emission with good chromaticity. Compounds in which some of the hydrogen atoms in these compounds are replaced with deuterium can also be used.

[0226] In addition to the phosphorescent compounds described above, other known phosphorescent compounds may be selected and used.

[0227] As TADF materials, fullerenes and their derivatives, acridines and their derivatives, eosin derivatives, etc. can be used. Also, metal-containing porphyrins containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), or palladium (Pd) can be used. As a metal-containing porphyrin, for example, the protoporphyrin-tin fluoride complex (SnF) shown in the following structural formula is used. ２ (Proto IX)), Mesoporphyrin-Tin Fluoride Complex (SnF ２ (Meso IX), hematoporphyrin-tin fluoride complex (SnF ２ (Hemato IX), coproporphyrin tetramethyl ester-tin fluoride complex (SnF ２ (Copro III-4Me)), Octaethylporphyrin-Tin Fluoride Complex (SnF ２ (OEP)), Ethioporphyrin-Tin Fluoride Complex (SnF ２ (Etio I)), Octaethylporphyrin-Platinum Chloride Complex (PtCl ２ OEP (Open Economic Programme) and others can also be mentioned.

[0228]

[0229] Furthermore, the following structural formulas represent 2-(biphenyl-4-yl)-4,6-bis(12-phenylindoro[2,3-a]carbazole-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ), 9-(4,6-diphenyl-1,3,5-triazine-2-yl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviation: PCCzTZn), 2-{4-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTZn), 2-[4-(10H-phenoxazine-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTZn), Heterocyclic compounds having one or both of a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring can also be used, such as PXZ-TRZ), 3-[4-(5-phenyl-5,10-dihydrophenadin-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviated as PPZ-3TPT), 3-(9,9-dimethyl-9H-acridine-10-yl)-9H-xanthene-9-one (abbreviated as ACRXTN), bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviated as DMAC-DPS), and 10-phenyl-10H,10'H-spiro[acridine-9,9'-anthracene]-10'-one (abbreviated as ACRSA). The heterocyclic compound is preferred because it has both a π-electron-excess heteroaromatic ring and a π-electron-deficient heteroaromatic ring, resulting in high electron transport and hole transport properties. Among the skeletons having a π-electron-deficient heteroaromatic ring, the pyridine skeleton, diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton), and triazine skeleton are preferred because they are stable and reliable. In particular, the benzoflopyrimidine skeleton, benzothienopyrimidine skeleton, benzoflopyrazine skeleton, and benzothienopyrazine skeleton are preferred because they have high acceptability and are reliable. Furthermore, among the skeletons having a π-electron-excess heteroaromatic ring, the acridine skeleton, phenoxazine skeleton, phenothiazine skeleton, furan skeleton, thiophene skeleton, and pyrrole skeleton are preferred because they are stable and reliable, and therefore it is preferable to have at least one of these skeletons.Furthermore, a dibenzofuran skeleton is preferred as the furan skeleton, and a dibenzothiophene skeleton is preferred as the thiophene skeleton. In addition, as the pyrrole skeleton, indole skeleton, carbazole skeleton, indrocarbazole skeleton, bicarbazole skeleton, and 3-(9-phenyl-9H-carbazole-3-yl)-9H-carbazole skeleton are particularly preferred. Substances in which a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring are directly bonded are particularly preferred because both the electron-donating and electron-accepting properties of the π-electron-rich heteroaromatic ring are strengthened, and the energy difference between the S1 and T1 levels is reduced, thus efficiently obtaining thermally activated delayed fluorescence. In addition, an aromatic ring to which an electron-withdrawing group such as a cyano group is bonded may be used instead of the π-electron-deficient heteroaromatic ring. Furthermore, aromatic amine skeletons, phenazine skeletons, etc., can be used as the π-electron-rich skeleton. Furthermore, as π-electron-deficient skeletons, xanthene skeletons, thioxanthene dioxide skeletons, oxadiazole skeletons, triazole skeletons, imidazole skeletons, anthraquinone skeletons, boron-containing skeletons such as phenylborane and volanthrene, aromatic rings having a nitrile group or a cyano group such as benzonitrile or cyanobenzene, heteroaromatic rings, carbonyl skeletons such as benzophenone, phosphine oxide skeletons, sulfone skeletons, etc., can be used. In this way, π-electron-deficient skeletons and π-electron-excess skeletons can be used instead of at least one of π-electron-deficient heteroaromatic rings and π-electron-excess heteroaromatic rings.

[0230]

[0231] Furthermore, a TADF material in which the singlet excited state and the triplet excited state are in thermal equilibrium may be used as the TADF material. Since such a TADF material has a shorter luminescence lifetime (excitation lifetime), it is possible to suppress the decrease in efficiency in the high-brightness region of the light-emitting device. Specifically, materials with the molecular structure shown below are examples.

[0232]

[0233] TADF materials are materials that have a small energy difference between the S1 and T1 levels and possess the ability to convert energy from triplet excitation energy to singlet excitation energy through reverse intersystem crossing. Therefore, triplet excitation energy can be upconverted to singlet excitation energy with only a small amount of thermal energy (reverse intersystem crossing), and singlet excited states can be efficiently generated. Furthermore, triplet excitation energy can be converted into luminescence.

[0234] Furthermore, an excited complex (also called an exciplex) that forms an excited state with two types of substances has an extremely small energy difference between the S1 and T1 levels and functions as a TADF material that can convert triplet excitation energy into singlet excitation energy.

[0235] Furthermore, the phosphorescence spectrum observed at low temperatures (for example, from 77K to 10K) can be used as an indicator of the T1 level. For TADF materials, when a tangent is drawn at the short-wavelength tail of the fluorescence spectrum and the energy at the wavelength of the extrapolation is taken as the S1 level, and when a tangent is drawn at the short-wavelength tail of the phosphorescence spectrum and the energy at the wavelength of the extrapolation is taken as the T1 level, it is preferable that the energy difference between S1 and T1 is 0.3 eV or less, and more preferably 0.2 eV or less.

[0236] Furthermore, when using TADF material as a light-emitting material, it is preferable that the S1 level of the host material is higher than the S1 level of the TADF material. Also, it is preferable that the T1 level of the host material is higher than the T1 level of the TADF material.

[0237] Various carrier transport materials can be used as the host material for the light-emitting layer, such as materials with electron transport properties and / or hole transport properties, and the TADF material mentioned above.

[0238] Preferred materials with hole transport properties include organic compounds having an amine skeleton or a π-electron-rich heteroaromatic ring skeleton. Preferred π-electron-rich heteroaromatic rings are condensed aromatic rings containing at least one of the following: acridine skeleton, phenoxazine skeleton, phenothiazine skeleton, furan skeleton, thiophene skeleton, and pyrrole skeleton. Specifically, carbazole rings, dibenzothiophene rings, or rings obtained by further condensing an aromatic ring or heteroaromatic ring with these are preferred.

[0239] Organic compounds having such hole-transporting properties more preferably have at least one of the following skeletons: a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and an anthracene skeleton. In particular, they may be aromatic amines having substituents including a dibenzofuran ring or a dibenzothiophene ring, aromatic monoamines having a naphthalene ring, or aromatic monoamines in which a 9-fluorenyl group is bonded to the nitrogen of the amine via an arylene group. Furthermore, it is preferable that these hole-transporting organic compounds are substances having an N,N-bis(4-biphenyl)amino group, as this allows for the creation of light-emitting devices with a good lifetime.

[0240] Preferred organic compounds include, for example, the following: 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviated as NPB), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-4,4'-diaminobiphenyl (abbreviated as TPD), N,N'-bis(9,9'-spirobi[9H-fluoren]-2-yl)-N,N'-diphenyl-4,4'-diaminobiphenyl (abbreviated as BSPB), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviated as BPAFLP), and 4-phenyl-3'-(9-phenylfluoren-9-yl ) Triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazole-3-yl)tri Compounds having an aromatic amine skeleton such as phenylamine (abbreviation: PCBNBB), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9'-spirobi[9H-fluoren]-2-amine (abbreviation: PCBASF), 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-di(N-carbazolyl)biphenyl (abbreviation: C BP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP), 9,9'-diphenyl-9H,9'H-3,3'-bicarbazole (abbreviation: PCCP), 3,9-bis(9-phenyl-9H-carbazole-3-yl)-9H-carbazole (abbreviation: PCCzPC), 9-(biphenyl-4-yl)-9'-phenyl-3,3'-bi-9H-carbazole (abbreviation: PCCzBP), 9,9'-bis(biphenyl-4-yl)-3,3'-bi-9H-carbazole (abbreviation: BisBPCz), 9,9'-Bis(biphenyl-3-yl)-3,3'-bi-9H-carbazole (abbreviation: BismBPCz), 9-(biphenyl-3-yl)-9'-(biphenyl-4-yl)-9H,9'H-3,3'-bicarbazole (abbreviation: mBPCCBP), 9-(2-naphthyl)-9'-phenyl-3,3'-bi-9H-carbazole (abbreviation: βNCCP), 9-(3-biphenyl)-9'-(2-naphthyl)-3,3'-bi-9H-carbazole (abbreviation: βNCCmBP), 9-(4-biphenyl)-9'-(2-naphthyl)-3, 3'-bi-9H-carbazole (abbreviation: βNCCBP), 9,9'-di-2-naphthyl-3,3'-9H,9'H-bicarbazole (abbreviation: BisβNCz), 9-(2-naphthyl)-9'-[1,1':4',1"-terphenyl]-3-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1"-terphenyl]-3-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1"-terphenyl]-5'-yl-3,3'-9H ,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':4',1"-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1"-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-(triphenylene-2-yl)-3,3'-9H,9'H-bicarbazole, 9-phenyl-9'-(triphenylene-2-yl)-3,3'-9H,9'H-bicarbazole (abbreviation: PCCzTp), 9,9'-bis(triphenylene-2-yl)-3,3'-9H,9'H-bicarbazole, 9-(4-biphenyl)-9'-(triphenylene-2-yl)-3,3'-9H,9'H-bicarbazole, 9-(triphenylene-2-yl)-9'-[1,1':3',1''-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-1-amine, 9-[3-(triphenylsilyl)phenyl]-3,Compounds having a carbazole skeleton such as 9'-bi-9H-carbazole (abbreviation: PSiCzCz), 9'-[3-(triphenylsilyl)phenyl]-9'H-9,3':6',9''-telcarbazole (abbreviation: PSiCzGI), 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-I) Examples include compounds having a thiophene skeleton such as 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviated as DBTFLP-IV), and compounds having a furan skeleton such as 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviated as DBF3P-II) and 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviated as mmDBFFLBi-II). Among the above, compounds having an aromatic amine skeleton or a carbazole skeleton are preferred because they have good reliability, high hole transportability, and contribute to reducing the driving voltage. Furthermore, organic compounds listed as examples of hole transportable materials in the hole transport layer can also be used.

[0241] For materials exhibiting electron transport properties, the electron mobility at which the square root of the electric field strength [V / cm] is 600 is 1 × 10⁻⁶. −７ cm ２ / Vs or more, preferably 1 x 10 −６ cm ２ A material having an electron mobility of / Vs or higher is preferred. However, any material with higher electron transport capabilities than holes can be used.

[0242] Examples of electron-transporting materials include bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviated as BeBq). ２Preferably, metal complexes such as bis(2-methyl-8-quinolinolato)(4-phenylphenololato)aluminum(III) (abbreviated as BAlq), bis(8-quinolinolato)zinc(II) (abbreviated as Znq), bis[2-(2-benzoxazollyl)phenololato]zinc(II) (abbreviated as ZnPBO), and bis[2-(2-benzothiazolyl)phenololato]zinc(II) (abbreviated as ZnBTZ), and organic compounds having a π-electron-deficient heteroaromatic ring are preferred. Examples of organic compounds having a π-electron-deficient heteroaromatic ring skeleton include organic compounds containing a heteroaromatic ring having an azole skeleton, organic compounds containing a heteroaromatic ring having a pyridine skeleton, organic compounds containing a heteroaromatic ring having a diazine skeleton, and organic compounds containing a heteroaromatic ring having a triazine skeleton.

[0243] Among these, organic compounds containing heteroaromatic rings having a diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton), organic compounds containing heteroaromatic rings having a pyridine skeleton, and organic compounds containing heteroaromatic rings having a triazine skeleton are preferred due to their good reliability. In particular, organic compounds containing heteroaromatic rings having a diazine (pyrimidine or pyrazine) skeleton and organic compounds containing heteroaromatic rings having a triazine skeleton have high electron transport properties and contribute to reducing the driving voltage. Furthermore, benzoflopyrimidine skeletons, benzothienopyrimidine skeletons, benzoflopyrazine skeletons, and benzothienopyrazine skeletons are preferred because they have high acceptor properties and good reliability.

[0244] As organic compounds having a π-electron-deficient heteroaromatic ring skeleton, the following organic compounds are preferred, for example: 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviated as PBD), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviated as TAZ), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazole-2-yl]benzene (abbreviated as OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazole-2-yl)phenyl]-9H-carbazole (abbreviated as Organic compounds having an azole skeleton such as CO11), 2,2',2''-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II), 4,4'-bis(5-methylbenzoxazole-2-yl)stilbene (abbreviation: BzOs), 3,5-bis[3-(9H-carbazole-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy), 1,3,5-tri[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB), vasophenanthroline (abbreviation: Bphen), vasocuproin (abbreviation: BCP), 2,9-di(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBphen), 2,2'-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviation: mPPhen2P), 2-[3-(2-triphenylenyl)phenyl]-1,10-phenan Organic compounds containing heteroaromatic rings with a pyridine skeleton, such as throline (abbreviation: mTpPPhen), 2-phenyl-9-(2-triphenylenyl)-1,10-phenanthroline (abbreviation: Ph-TpPhen), 2-[4-(9-phenanthryl)-1-naphthyl]-1,10-phenanthroline (abbreviation: PnNPhen), and 2-[4-(2-triphenylenyl)phenyl]-1,10-phenanthroline (abbreviation: pTpPPhen), 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]Quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]Quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-(9H-carbazole-9-yl)biphenyl-3-yl]dibenzo[f,h]Quinoxaline (abbreviation: 2mCzBPDBq), 2-[4'-(9-phenyl-9H-carbazole-3-yl)-3,1'-biphenyl-1-yl]dibenzo[f,h]Quinoxaline (abbreviation: 2mpPCBPDBq), 2-[4-(3, 6-diphenyl-9H-carbazole-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzPDBq-III), 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 7mDBTPDBq-II), and 6-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II), 2-{3-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}dibenzo[f,h]quinoxaline Noxaline (abbreviation: 2mPCCzPDBq), 9-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]flo[2,3-b]pyrazine (abbreviation: 9mDBtBPNfpr), 9-[3'-(dibenzothiophen-4-yl)biphenyl-4-yl]naphtho[1',2':4,5]flo[2,3-b]pyrazine (abbreviation: 9pmDBtBPNfpr), 4,6-bis[3-(phenanthren-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(dibenzothio [Phen-4-yl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis[3-(9H-carbazole-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm), 9,9'-[pyrimidine-4,6-diylbis(biphenyl-3,3'-diyl)]bis(9H-carbazole) (abbreviation: 4,6mCzBP2Pm), 8-(biphenyl-4-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzoflo[3,2-d]pyrimidine (abbreviation: 8BP-4mDBtPBfpm), 3,8-bis[3-(dibenzothiophen-4-yl)phenyl]benzoflo[2,3-b]pyrazine (abbreviation: 3,8mDBtP2Bfpr), 11-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]phenantro[9',10':4,5]flo[2,3-b]pyrazine (abbreviation: 11mDBtBPPnfpr), 4,8-bis[3-(dibenzothiophen-4-yl)phenyl]-[1]benzoflo[3,2-d]pyrimidine (abbreviation: 4,8mDBtP2Bfpm), 8-[3'-(dibenzothiophen-4-yl)biphenyl [Nyl-3-yl]naphtho[1',2':4,5]flou[3,2-d]pyrimidine (abbreviation: 8mDBtBPNfpm), 8-([2,2'-binaphthalene]-6-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzoflou[3,2-d]pyrimidine (abbreviation: 8(βN2)-4mDBtPBfpm), 2,2'-(pyridine-2,6-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviation: 2,6(P-Bqn)2Py), 2,2'-(pyridine-2,6-diyl)bis{4-[4-(2-naphthyl)pheni 6-6-phenylpyrimidine (abbreviation: 2,6(NP-PPm)2Py), 6-(biphenyl-3-yl)-4-[3,5-bis(9H-carbazole-9-yl)phenyl]-2-phenylpyrimidine (abbreviation: 6mBP-4Cz2PPm), 2,6-bis(4-naphthalene-1-ylphenyl)-4-[4-(3-pyridyl)phenyl]pyrimidine (abbreviation: 2,4NP-6PyPPm), 4-[3,5-bis(9H-carbazole-9-yl)phenyl]-2-phenyl-6-(biphenyl-4-yl)pyrimidine (abbreviation: 6BP-4 Organic compounds having a diazine skeleton such as Cz2PPm), 7-[4-(9-phenyl-9H-carbazole-2-yl)quinazoline-2-yl]-7H-dibenzo[c,g]carbazole (abbreviation: PC-cgDBCzQz), 8-(p-terphenyl-3-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzoflou[3,2-d]pyrimidine (abbreviation: 8mpTP-4mDBtPBfpm), 2-(biphenyl-4-yl)-4-phenyl-6-(9,9'-spirobio[9H-fluoren]-2-yl)-1,3,5-triazine (abbreviation: BP-SFTZn), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-8-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mBnfBPTZn), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-6-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mBnfBPTZn-02), 2-{4-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9- [Iyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTZn), 9-[3-(4,6-diphenyl-1,3,5-triazine-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviation: mPCCzPTZn-02), 2-[3'-(9,9-dimethyl-9H-fluoren-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mFBPTZn), 5-[3-(4,6-diphenyl-1,3,5-triazine-2 [-yl)phenyl]-7,7-dimethyl-5H,7H-indeno[2,1-b]carbazole (abbreviation: mINc(II)PTZn), 2-{3-[3-(dibenzothiophen-4-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mDBtBPTZn), 2,4,6-tris[3'-(pyridin-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviation: TmPPPyTz), 2-[3-(2,6-dimethyl-3-pyridinyl)-5-(9-phenanthryl) [phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mPn-mDMePyPTZn), 11-[4-(biphenyl-4-yl)-6-phenyl-1,3,5-triazine-2-yl]-11,12-dihydro-12-phenylindoro[2,3-a]carbazole (abbreviation: BP-Icz(II)TZn), 2-[3'-(triphenylene-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mTpBPTZn), 3-[9-(4,6-diphenyl-1,3,5-triazine-2-yl)-2-dibenzofuranyl]-9-phenyl-9H-carbazole (abbreviation: PCDBfTZn), 2-(biphenyl-3-yl)-4-phenyl-6-[8-([1,1':4',1''-terphenyl]-4-yl)-1-dibenzofuranyl]-1,3,5-triazine (abbreviation: mBP-TPDBfTZn), 2-[4-(2-naphthyl)phenyl]-4-phenyl-6-spiro[9H-F Luoren-9,9'-[9H]xanthene]-4-yl-1,3,5-triazine (abbreviation: βNP-SFx(4)Tzn), 9,9'-{6-[3-(triphenylsilyl)phenyl]-1,3,5-triazine-2,4-diyl}bis(9H-carbazole) (abbreviation: SiTrzCz2), 2-phenyl-4,6-bis[3-(triphenylsilyl)phenyl]-1,3,5-triazine (abbreviation: mSiTrz), 11 −[4-(biphenyl-4-yl)-6-phenyl-1,3,5-triazine-2-yl]-11,12-dihydro-12-(biphenyl-3-yl)indro[2,3-a]carbazole (abbreviation: BP-mBPIcz(II)TZn),3-{3-[9-(4,6-diphenyl-1,3,5-triazine-2-yl)-2-dibenzofuranyl]phenyl}-9-phenyl-9H-carbazole (abbreviation: mPCPDBf) TZn), 9,9'-[6-(biphenyl-4-yl)-2-phenyl-1,3,5-triazine-4,3''-diyl]bis(9H-carbazole) (abbreviation: Cz-pmCzBPTZn), 3-phenyl-9-[4-phenyl-6-(9-phenyl-3-dibenzofuranyl)-1,3,5-triazine-2-yl]-9H-carbazole (abbreviation: PDBf-PCzTZn), 9-[4-(4,6-diphenyl-1,3,Examples include organic compounds containing a heteroaromatic ring having a triazine skeleton, such as 5-triazine-2-yl)-2-dibenzothienyl]-2-phenyl-9H-carbazole (abbreviation: PCzDBtTzn). Furthermore, organic compounds containing a heteroaromatic ring having a diazine skeleton, or a heteroaromatic ring having a pyridine skeleton, or a heteroaromatic ring having a triazine skeleton are preferred due to their good reliability. In particular, organic compounds containing a heteroaromatic ring having a diazine (pyrimidine or pyrazine) skeleton, or a heteroaromatic ring having a triazine skeleton, exhibit high electron transport properties and contribute to reducing the driving voltage.

[0245] The TADF materials listed above can be used as host materials. When a TADF material is used as a host material, the triplet excitation energy generated by the TADF material is converted into singlet excitation energy through reverse intersystem crossing, and this energy is then transferred to the light-emitting material, thereby increasing the luminescence efficiency of the light-emitting device. In this case, the TADF material functions as an energy donor, and the light-emitting material functions as an energy acceptor.

[0246] This is very effective when the above-mentioned luminescent material is a fluorescent luminescent material. Also, in order to obtain high luminescence efficiency in this case, the S of the TADF material １ The energy level is S of the fluorescent material. １ It is preferable that the level be higher than the level. Also, the T of the TADF material １ The energy level is S of the fluorescent material. １ It is preferable that the level be higher than the level of the TADF material. １ The energy level is the T of the fluorescent material. １ A level higher than the current level is preferable.

[0247] Furthermore, it is preferable to use a TADF material that exhibits emission that overlaps with the wavelength of the lowest-energy absorption band of the fluorescent material. This is preferable because it allows for a smooth transfer of excitation energy from the TADF material to the fluorescent material, resulting in efficient emission.

[0248] Furthermore, for singlet excitation energy to be efficiently generated from triplet excitation energy by reverse intersystem crossing, it is preferable that carrier recombination occurs in the TADF material. It is also preferable that the triplet excitation energy generated in the TADF material does not transfer to the triplet excitation energy of the fluorescent material. To achieve this, it is preferable that the fluorescent material has protecting groups around the luminescent phosphoform (the skeleton that causes luminescence). Preferred protecting groups are substituents without π bonds, saturated hydrocarbons, specifically alkyl groups having 3 to 10 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3 to 10 carbon atoms, and trialkylsilyl groups having 3 to 10 carbon atoms. It is even more preferable to have multiple protecting groups. Substituents without π bonds have poor carrier transport function, and therefore can increase the distance between the TADF material and the luminescent phosphoform of the fluorescent material with little effect on carrier transport or carrier recombination. Here, the luminescent phosphoform refers to the atomic group (skeleton) that causes luminescence in the fluorescent material. The luminescent phosphophore preferably has a skeleton containing π bonds, preferably contains an aromatic ring, and preferably has a condensed aromatic ring or a condensed heteroaromatic ring. Examples of such luminescent phosphophores include phenanthrene skeletons, stilbene skeletons, acridone skeletons, phenoxazine skeletons, phenothiazine skeletons, naphthalene skeletons, anthracene skeletons, fluorene skeletons, chrysene skeletons, triphenylene skeletons, tetracene skeletons, pyrene skeletons, perylene skeletons, coumarin skeletons, quinacridone skeletons, and naphthobisbenzofuran skeletons. Fluorescent materials having naphthalene, anthracene, fluorene, chrysene, triphenylene, tetracene, pyrene, perylene, coumarin, quinacridone, and naphthobisbenzofuran skeletons are particularly preferred due to their high fluorescence quantum yield.

[0249] When using a fluorescent material as a light-emitting material, a material having an acene skeleton, particularly an anthracene skeleton, is preferred as the host material. Using a material having an anthracene skeleton as the host material for a fluorescent material makes it possible to realize a light-emitting layer with good luminescence efficiency and durability. Among the materials having an anthracene skeleton to be used as the host material, a material having a diphenylanthracene skeleton, particularly a 9,10-diphenylanthracene skeleton, is preferred because it is chemically stable. Furthermore, while a carbazole skeleton is preferred as the host material because it improves hole injection and transport, a benzocarbazole skeleton, in which a benzene ring is further condensed into the carbazole, is even more preferred because the HOMO level is about 0.1 eV higher than when only a carbazole skeleton is present, making it easier for holes to enter. In particular, a dibenzocarbazole skeleton is preferred as the host material is about 0.1 eV higher than when only a carbazole skeleton is present, making it easier for holes to enter, as well as providing excellent hole transport and high heat resistance. Therefore, a more preferred host material is a substance having a 9,10-diphenylanthracene skeleton and a carbazole skeleton (or a benzocarbazole skeleton or dibenzocarbazole skeleton). Furthermore, from the viewpoint of hole injection and transport, a benzofluorene skeleton or a dibenzofluorene skeleton may be used instead of the carbazole skeleton. Also, it is preferable to include a dibenzofuran skeleton because reliability can be ensured without lowering the T1 level.

[0250] Examples of such substances include 9-phenyl-3-[4-(10-phenyl-9-antryl)phenyl]-9H-carbazole (abbreviated as PCzPA), 3-[4-(1-naphthyl)phenyl]-9-phenyl-9H-carbazole (abbreviated as PCPN), 9-[4-(10-phenyl-9-antryl)phenyl]-9H-carbazole (abbreviated as CzPA), and 7-[4-(10-phenyl-9-antryl) Phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: cgDBCzPA), 6-[3-(9,10-diphenyl-2-anthryl)phenyl]benzo[b]naphtho[1,2-d]furan (abbreviation: 2mBnfPPA), 9-phenyl-10-[4-(9-phenyl-9H-fluoren-9-yl)biphenyl-4'-yl]anthracene (abbreviation: FLPPA), 9-(1-naphthyl)-10-[4-(2 -Naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth), 9-(1-naphthyl)-10-(2-naphthyl)anthracene (abbreviation: α,βADN), 2-(10-phenylanthracene-9-yl)dibenzofuran, 2-(10-phenyl-9-antryl)benzo[b]naphtho[2,3-d]furan (abbreviation: Bnf(II)PhA), 9-(2-naphthyl)-10-[3-(2-naphthyl) Examples include [phenyl]anthracene (abbreviated as βN-mβNPAnth), 1-{4-[10-(biphenyl-4-yl)-9-anthryl]phenyl}-2-ethyl-1H-benzimidazole (abbreviated as EtBImPBPhA), and 7-(phenyl-2,3,4,5,6-d5)-1-[10-(phenyl-2,3,4,5,6-d5)-9-anthryl]dibenzofuran (abbreviated as PDBfPhA-d10). In particular, CzPA, cgDBCzPA, 2mBnfPPA, and PCzPA are preferred choices because they exhibit very good properties.

[0251] Note that the host material may be a material obtained by mixing a plurality of substances. When using a mixed host material, it is preferable to mix a material having electron transporting properties and a material having hole transporting properties. By mixing a material having electron transporting properties and a material having hole transporting properties, the transporting properties of the light emitting layer 113 can be easily adjusted, and the control of the recombination region can also be easily performed. The weight ratio of the content of the material having hole transporting properties to the material having electron transporting properties is preferably Hole transporting material: Electron transporting material = 1:19 to 19:1.

[0252] In addition, as a part of the above mixed material, a phosphorescent substance can be used. The phosphorescent substance can be used as an energy donor that supplies excitation energy to the fluorescent substance when the fluorescent substance is used as the light emitting substance.

[0253] Also, an exciplex may be formed between these mixed materials. By selecting a combination that forms an exciplex that emits light overlapping the wavelength of the absorption band on the lowest energy side of the light emitting substance, energy transfer becomes smooth and light emission can be obtained efficiently, which is preferable. In addition, since the driving voltage is also lowered by using this configuration, it is preferable.

[0254] Note that when at least one of the materials forming the exciplex is a phosphorescent substance, the triplet excitation energy can be efficiently converted into singlet excitation energy by reverse intersystem crossing.

[0255] As a combination of materials that efficiently form an exciplex, it is preferable that the HOMO level of the material having hole transporting properties is higher than the HOMO level of the material having electron transporting properties. Also, it is preferable that the LUMO level of the material having hole transporting properties is higher than the LUMO level of the material having electron transporting properties. Note that the LUMO level and HOMO level of the material can be derived from the electrochemical characteristics (reduction potential and oxidation potential) of the material measured by cyclic voltammetry (CV) measurement.

[0256] The formation of excited complexes can be confirmed, for example, by comparing the emission spectra of a hole-transporting material, an electron-transporting material, and a mixed film made by mixing these materials, and observing that the emission spectrum of the mixed film shifts to a longer wavelength than the emission spectra of each individual material (or has a new peak on the longer wavelength side). Alternatively, it can be confirmed by comparing the transient photoluminescence (PL) of a hole-transporting material, the transient PL of an electron-transporting material, and the transient PL of a mixed film made by mixing these materials, and observing differences in the transient response, such as the transient PL lifetime of the mixed film having a longer lifetime component or a larger proportion of the delayed component than the transient PL lifetime of each individual material. Furthermore, the transient PL mentioned above may be read as transient electroluminescence (EL). That is, the formation of excited complexes can also be confirmed by comparing the transient EL of a hole-transporting material, the transient EL of an electron-transporting material, and the transient EL of a mixed film made by mixing these materials, and observing the differences in the transient response.

[0257] The electron transport layer 114 is a layer containing an electron-transporting material. The electron-transporting material has an electron mobility of 1 × 10⁻¹⁶ at an electric field strength [V / cm] square root of 600. −７ cm ２ / Vs or more, preferably 1 x 10 −６ cm ２ A substance having an electron mobility of 1 / Vs or higher is preferred. However, any substance that has higher electron transport capacity than holes can be used. As the above organic compound, an organic compound having a π-electron-deficient heteroaromatic ring is preferred. As an organic compound having a π-electron-deficient heteroaromatic ring, it is preferable that it be any or more of the following: an organic compound containing a heteroaromatic ring having an azole skeleton, an organic compound containing a heteroaromatic ring having a pyridine skeleton, an organic compound containing a heteroaromatic ring having a diazine skeleton, and an organic compound containing a heteroaromatic ring having a triazine skeleton.

[0258] As for materials having electron-transporting properties that can be used in the electron transport layer 114, the organic compounds listed as preferred organic compounds having electron-transporting properties for use as a host material in the light-emitting layer 113 can be used in the same way.

[0259] Among the organic compounds listed as preferred electron-transporting organic compounds for use as host materials, organic compounds containing a heteroaromatic ring having a diazine skeleton, organic compounds containing a heteroaromatic ring having a pyridine skeleton, and organic compounds containing a heteroaromatic ring having a triazine skeleton are preferred due to their good reliability. In particular, organic compounds containing a heteroaromatic ring having a diazine (pyrimidine or pyrazine) skeleton and organic compounds containing a heteroaromatic ring having a triazine skeleton have high electron transport properties and contribute to reducing the driving voltage. In particular, organic compounds having a phenanthroline skeleton such as mTpPPhen, PnNPhen, and mPPhen2P are preferred, and organic compounds having a phenanthroline dimer structure such as mPPhen2P are more preferred due to their superior stability.

[0260] The electron transport layer 114 may have a laminated structure. Furthermore, the layer in contact with the light-emitting layer 113 in the laminated electron transport layer 114 may function as a hole-blocking layer. When the electron transport layer in contact with the light-emitting layer functions as a hole-blocking layer, it is preferable to use a material whose HOMO level is 0.5 eV or more lower than the HOMO level of the material contained in the light-emitting layer 113.

[0261] The electron injection layer 115 may be provided by a layer containing alkali metals or alkaline earth metals, compounds or complexes of alkali metals or alkaline earth metals, or 1,1'-pyridine-2,6-diyl-bis(1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine) (abbreviated as hpp2Py). The electron injection layer 115 may also be a layer containing these materials within a layer made of an electron-transporting substance.

[0262] Alternatively, a charge generation layer 116 can be provided instead of the electron injection layer 115 (Figure 6B). The charge generation layer 116 is a layer that can inject holes into the layer in contact with the cathode side and electrons into the layer in contact with the anode side by applying a potential. The charge generation layer 116 includes at least a p-type layer 117. The p-type layer 117 is preferably formed using one of the composite materials listed above as a material that can constitute the hole injection layer 111. The p-type layer 117 may also be formed by laminating a film containing the acceptor material and a film containing the hole transport material as materials that constitute the composite material. By applying a potential to the p-type layer 117, electrons are injected into the electron transport layer 114 and holes into the cathode, and the light-emitting device operates.

[0263] Furthermore, it is preferable that the charge generation layer 116 includes, in addition to the p-type layer 117, one or both of the electron relay layer 118 and the electron injection buffer layer 119.

[0264] The electron relay layer 118 contains at least an electron-transporting material and has the function of preventing interaction between the electron injection buffer layer 119 and the p-type layer 117, thereby smoothly transferring electrons. Preferably, the LUMO level of the electron-transporting material contained in the electron relay layer 118 is located between the LUMO level of the acceptor material in the p-type layer 117 and the LUMO level of the material contained in the layer in contact with the charge generation layer 116 in the electron transport layer 114. The specific energy level of the LUMO level of the electron-transporting material used in the electron relay layer 118 is preferably -5.0 eV or higher, preferably -5.0 eV or higher and -3.0 eV or lower, more preferably -4.30 eV or higher and -3.00 eV or lower, and more preferably -4.30 eV or higher and -3.30 eV or lower, as this suppresses an increase in the driving voltage. Furthermore, it is preferable to use a phthalocyanine-based material or a metal complex having a metal-oxygen bond and an aromatic ligand as the electron-transporting material used in the electron relay layer 118.

[0265] Specifically, the electron-transporting material used in the electron relay layer 118 can be a perylenetetracarboxylic acid derivative such as diquinoxalino[2,3-a:2',3'-c]phenazine (abbreviated as HATNA), 2,3,8,9,14,15-hexafluorodiquinoxalino[2,3-a:2',3'-c]phenazine (abbreviated as HATNA-F6), 3,4,9,10-perylenetetracarboxylic acid diimide (abbreviated as PTCDI), 3,4,9,10-perylenetetracarboxyl-bis-benzimidazole (abbreviated as PTCBI), (C60-Ih)[5,6]fullerene (abbreviated as C60), or (C70-D5h)[5,6]fullerene (abbreviated as C70). Furthermore, compounds having a heterophan skeleton, which is a cyclophane skeleton containing a heterocycle, can be used, and examples of such compounds include phthalocyanine (abbreviated as H ２ Phthalocyanine compounds such as Pc can be used. In addition, metal phthalocyanines containing copper, zinc, cobalt, iron, chromium, nickel, etc., such as copper phthalocyanine (abbreviated as CuPc), zinc phthalocyanine (abbreviated as ZnPc), cobalt phthalocyanine (abbreviated as CoPc), iron phthalocyanine (abbreviated as FePc), tin phthalocyanine (abbreviated as SnPc), tin oxide phthalocyanine (abbreviated as SnOPc), titanium oxide phthalocyanine (abbreviated as TiOPc), and vanadium oxide phthalocyanine (abbreviated as VOPc), and their derivatives can be used. Phthalocyanine-based metal complexes such as copper phthalocyanine or zinc phthalocyanine, or 2,3,8,9,14,15-hexafluorodiquinoxalino[2,3-a:2',3'-c]phenazine are particularly preferred.

[0266] The electron injection buffer layer 119 can be made of materials with high electron injection potential, such as alkali metals, alkaline earth metals, rare earth metals, and compounds thereof (alkali metal compounds (including oxides such as lithium oxide, halides, and carbonates such as lithium carbonate and cesium carbonate), alkaline earth metal compounds (including oxides, halides, and carbonates), or rare earth metal compounds (including oxides, halides, and carbonates)).

[0267] Furthermore, if the electron injection buffer layer 119 is formed by including an electron-transporting substance and a donor substance, the donor substance can include alkali metals, alkaline earth metals, rare earth metals, and compounds thereof (alkali metal compounds (including oxides such as lithium oxide, halides, and carbonates such as lithium carbonate and cesium carbonate), alkaline earth metal compounds (including oxides, halides, and carbonates), or rare earth metal compounds (including oxides, halides, and carbonates)), as well as organic compounds such as tetratianaphthalene (abbreviated as TTN), nickerosene, and decamethylnickerosene. The electron-transporting substance can be formed using the same materials as those used to constitute the electron transport layer 114 described above.

[0268] The second electrode 102 is an electrode that includes a cathode. The second electrode 102 may have a layered structure, in which case the layer in contact with the organic compound layer 103 functions as the cathode. As the material forming the cathode, metals, alloys, electrically conductive compounds, and mixtures thereof with a small work function (specifically 3.8 eV or less) can be used. Specific examples of such cathode materials include alkali metals such as lithium (Li) or cesium (Cs), and elements belonging to Group 1 or Group 2 of the periodic table such as magnesium (Mg), calcium (Ca), and strontium (Sr), and alloys (MgAg, AlLi) and compounds (lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF)) containing these. ２ Examples include rare earth metals such as europium (Eu) and ytterbium (Yb), and alloys containing these. However, by providing an electron injection layer 115 or a thin film of the aforementioned material with a small work function between the second electrode 102 and the electron transport layer, various conductive materials such as Al, Ag, ITO, silicon, or indium oxide-tin oxide containing silicon oxide can be used as cathodes, regardless of the magnitude of the work function.

[0269] Furthermore, if the second electrode 102 is formed from a material that is transparent to visible light, it can be made into a light-emitting device that emits light from the second electrode 102 side. In addition, the light extraction efficiency can be improved by forming a cap layer on the second electrode 102 from a material with a high refractive index (for example, a material with a paraphotonic refractive index (NO) of 1.90 or higher at a wavelength of 450 nm, a paraphotonic refractive index (NO) of 1.80 or higher at a wavelength of 520 nm, or a paraphotonic refractive index (NO) of 1.75 or higher at a wavelength of 630 nm). It is preferable to use an organic compound for the cap layer because it is easy to form.

[0270] These conductive materials can be formed using dry methods such as vacuum deposition or sputtering, inkjet printing, or spin coating. Alternatively, they may be formed using a wet method with a sol-gel process, or using a metal paste.

[0271] Furthermore, various methods can be used to form the organic compound layer 103, regardless of whether they are dry or wet methods. For example, vacuum deposition, gravure printing, offset printing, screen printing, inkjet printing, or spin coating may be used.

[0272] Furthermore, each electrode or layer described above may be formed using different film deposition methods.

[0273] Next, an embodiment of a light-emitting device (also called a stacked element or tandem element) with a configuration in which multiple light-emitting units are stacked will be described with reference to Figure 6C. This light-emitting device has multiple light-emitting units between the anode and the cathode. Each light-emitting unit has a configuration substantially similar to the organic compound layer 103 shown in Figure 6A. In other words, the light-emitting device shown in Figure 6C is a light-emitting device having multiple light-emitting units, while the light-emitting device shown in Figure 6A or Figure 6B is a light-emitting device having one light-emitting unit.

[0274] In Figure 6C, a first light-emitting unit 511 and a second light-emitting unit 512 are stacked between the first electrode 501 and the second electrode 502, and an intermediate layer 513 is provided between the first light-emitting unit 511 and the second light-emitting unit 512. The first electrode 501 and the second electrode 502 correspond to the first electrode 101 and the second electrode 102 in Figure 6A, respectively, and the same explanation as described in the explanation of Figure 6A can be applied. Furthermore, the first light-emitting unit 511 and the second light-emitting unit 512 may be made of the same material or different materials.

[0275] The intermediate layer 513 has the function of injecting electrons into one light-emitting unit and holes into the other light-emitting unit when a voltage is applied to the first electrode 501 and the second electrode 502. That is, in Figure 6C, when a voltage is applied such that the potential of the anode is higher than the potential of the cathode, the intermediate layer 513 should inject electrons into the first light-emitting unit 511 and holes into the second light-emitting unit 512.

[0276] The intermediate layer 513 is preferably formed with the same configuration as the charge generation layer 116 described in Figure 6B. Because the composite material of organic compounds and metal oxides has excellent carrier implantation and carrier transport properties, it can achieve low-voltage and low-current operation.

[0277] Furthermore, if the anode side of the light-emitting unit is in contact with the intermediate layer 513, the intermediate layer 513 can also serve as the hole injection layer of the light-emitting unit, so the light-emitting unit does not need to have a hole injection layer.

[0278] Furthermore, when an electron injection buffer layer 119 is provided in the intermediate layer 513, the electron injection buffer layer 119 plays the role of an electron injection layer in the anode-side light-emitting unit, so it is not necessarily required to form an electron injection layer in the anode-side light-emitting unit.

[0279] Figure 6C illustrates a light-emitting device having two light-emitting units, but the same principles can be applied to light-emitting devices with three or more stacked light-emitting units. As in the light-emitting device according to this embodiment, by arranging multiple light-emitting units separated between a pair of electrodes by an intermediate layer 513, high-brightness light emission can be achieved while maintaining a low current density, and a long-life element can be realized. Furthermore, a light-emitting device that can be driven at a low voltage and consumes little power can be realized.

[0280] Furthermore, by making the emission colors of each light-emitting unit different, it is possible to obtain a desired hue of emission from the entire light-emitting device. For example, in a light-emitting device having two light-emitting units, it is possible to obtain a light-emitting device that emits white light as a whole by obtaining red and green hues of emission from the first light-emitting unit and blue hues of emission from the second light-emitting unit. In addition, by having the light-emitting central material of each light-emitting unit exhibit the same hue of emission, it is possible to provide a light-emitting device with extremely high current efficiency.

[0281] Furthermore, each layer, such as the organic compound layer 103, the first light-emitting unit 511, the second light-emitting unit 512, and the charge generation layer, as well as the electrodes, can be formed using methods such as vapor deposition (including vacuum deposition), droplet ejection (also known as inkjet printing), coating, and gravure printing. They may also contain low-molecular-weight materials, medium-molecular-weight materials (including oligomers and dendrimers), or polymer materials.

[0282] (Embodiment 4) This embodiment describes an example in which a light-emitting device according to one aspect of the present invention is used as a display element for a display device. In this embodiment, the light-emitting device is shown in a shape formed by photolithography, but it may also be formed by a method using a fine metal mask or the like.

[0283] As illustrated in Figures 7A and 7B, multiple light-emitting devices 130 are formed on the insulating layer 175 to constitute the display device 100.

[0284] The display device has a pixel section 177 in which a plurality of pixels 178 are arranged in a matrix. The pixels 178 include sub-pixels 110R, sub-pixels 110G, and sub-pixels 110B.

[0285] In this specification, when describing matters common to, for example, sub-pixels 110R, 110G, and 110B, they may be referred to simply as sub-pixel 110. Similarly, when describing matters common to other components distinguished by letters, the letters may be omitted and the corresponding symbols used.

[0286] Sub-pixel 110R emits red light, sub-pixel 110G emits green light, and sub-pixel 110B emits blue light. This allows an image to be displayed on the pixel section 177. In this embodiment, three sub-pixels of red (R), green (G), and blue (B) are used as an example, but combinations of other colors of sub-pixels may also be used. Furthermore, the number of sub-pixels is not limited to three, but may be four or more. Examples of four sub-pixels include four sub-pixels of R, G, B, and white (W), four sub-pixels of R, G, B, and yellow (Y), and four sub-pixels of R, G, B, and infrared (IR).

[0287] In this specification and other documents, the row direction may be referred to as the X direction and the column direction as the Y direction. The X and Y directions intersect, for example, perpendicularly.

[0288] Figure 7A shows an example where subpixels of different colors are arranged in the X direction, and subpixels of the same color are arranged in the Y direction. Alternatively, subpixels of different colors may be arranged in the Y direction, and subpixels of the same color may be arranged in the X direction.

[0289] A connecting portion 140 and a region 141 may be provided on the outside of the pixel portion 177. The region 141 is provided between the pixel portion 177 and the connecting portion 140. An organic compound layer 103 is provided in the region 141. A conductive layer 151C is provided in the connecting portion 140.

[0290] Figure 7A shows an example where region 141 and connection portion 140 are located to the right of the pixel portion 177, but the positions of region 141 and connection portion 140 are not particularly limited. Also, region 141 and connection portion 140 may be singular or multiple.

[0291] Figure 7B is an example of a cross-sectional view between the dashed line A1-A2 in Figure 7A. As shown in Figure 7B, the display device has an insulating layer 171, a conductive layer 172 on the insulating layer 171, an insulating layer 173 on the insulating layer 171 and on the conductive layer 172, an insulating layer 174 on the insulating layer 173, and an insulating layer 175 on the insulating layer 174. The insulating layer 171 is provided on a substrate (not shown). The insulating layer 175, insulating layer 174, and insulating layer 173 are provided with openings that reach the conductive layer 172, and plugs 176 are provided to fill these openings.

[0292] In the pixel section 177, a light-emitting device 130 is provided on an insulating layer 175 and a plug 176. A protective layer 131 is provided so as to cover the light-emitting device 130. A substrate 120 is bonded to the protective layer 131 by a resin layer 122. Preferably, an inorganic insulating layer 125 and an insulating layer 127 on the inorganic insulating layer 125 are provided between adjacent light-emitting devices 130.

[0293] In Figure 7B, multiple cross-sections of the inorganic insulating layer 125 and the insulating layer 127 are shown, but when the display device is viewed from above, it is preferable that the inorganic insulating layer 125 and the insulating layer 127 are connected as one unit. In other words, it is preferable that the inorganic insulating layer 125 and the insulating layer 127 are insulating layers having an opening on the first electrode.

[0294] In Figure 7B, the light-emitting devices 130 are shown as light-emitting devices 130R, 130G, and 130B. Light-emitting devices 130R, 130G, and 130B are to exhibit different emission colors. For example, light-emitting device 130R can emit red light, light-emitting device 130G can emit green light, and light-emitting device 130B can emit blue light. In addition, light-emitting devices 130R, 130G, or 130B may emit other visible light or infrared light. In Figure 7B, light-emitting devices 130R and 130G, and light-emitting devices 130G and 130B can be said to be adjacent light-emitting devices.

[0295] One embodiment of the present invention can be a top-emission type, for example, which emits light in the opposite direction to the substrate on which the light-emitting device is formed. Alternatively, one embodiment of the present invention may be a bottom-emission type.

[0296] The light-emitting device 130R is a light-emitting device that emits red light (phosphorescence is preferred), and preferably has the configuration shown in Embodiment 3. It has a first electrode 101R (pixel electrode) consisting of a conductive layer 151R and a conductive layer 152R, a first layer 135R on the first electrode 101R, a common layer 136 on the first layer 135R, and a second electrode (common electrode) 102 on the common layer 136. The common layer 136 is preferably an electron injection layer.

[0297] The light-emitting device 130G is a light-emitting device that emits green light (phosphorescence is preferred), and preferably has the configuration shown in Embodiment 3. It has a first electrode 101G (pixel electrode) consisting of a conductive layer 151G and a conductive layer 152G, a first layer 135G on the first electrode 101G, a common layer 136 on the first layer 135G, and a second electrode (common electrode) 102 on the common layer 136. The common layer 136 is preferably an electron injection layer.

[0298] The light-emitting device 130B is a light-emitting device that emits blue light (fluorescence is preferred), and preferably has the configuration shown in Embodiment 3. It has a first electrode 101B (pixel electrode) consisting of a conductive layer 151B and a conductive layer 152B, a first layer 135B on the first electrode 101B, a common layer 136 on the first layer 135B, and a second electrode (common electrode) 102 on the common layer 136. The common layer 136 is preferably an electron injection layer.

[0299] Of the pixel electrodes (first electrodes) and common electrodes (second electrodes) of the light-emitting device, one functions as the anode and the other as the cathode. In this embodiment, unless otherwise specified, the pixel electrodes function as the anode and the common electrodes function as the cathode.

[0300] The first layer 135R, the first layer 135G, and the first layer 135B are independent island-like layers for each light-emitting device or for each light-emitting color. Furthermore, it is preferable that the first layer 135R, the first layer 135G, and the first layer 135B do not overlap with each other. Note that the first layers formed on multiple light-emitting devices 130 in the light-emitting device, such as the first layer 135R, the first layer 135G, and the first layer 135B, may be collectively referred to as the first layer group 135A. By providing the first layer group 135A in an island-like manner for each light-emitting device 130, leakage current between adjacent light-emitting devices 130 can be suppressed even in high-definition display devices. This prevents crosstalk and enables the realization of a display device with extremely high contrast. In particular, it enables the realization of a display device with high current efficiency at low brightness.

[0301] The island-shaped first layer group 135A is formed by depositing an EL film for each emission color and processing the EL film using photolithography.

[0302] Preferably, the first layer 135 is provided so as to cover the top and side surfaces of the first electrode 101 (pixel electrode) of the light-emitting device 130. This makes it easier to increase the aperture ratio of the display device compared to a configuration in which the edge of the first layer 135 is located inside the edge of the pixel electrode. In addition, by covering the side surfaces of the pixel electrode of the light-emitting device 130 with the first layer 135, contact between the first electrode 101 and the second electrode 102 can be suppressed, thereby suppressing short circuits of the light-emitting device 130.

[0303] Furthermore, in a display device according to one aspect of the present invention, it is preferable that the first electrode 101 (pixel electrode) of the light-emitting device be in a stacked configuration. For example, in the example shown in Figure 7B, the first electrode 101 of the light-emitting device 130 is in a stacked configuration of a conductive layer 151 provided on the insulating layer 171 side and a conductive layer 152 provided on the organic compound layer side.

[0304] For example, a metallic material can be used as the conductive layer 151. Specifically, metals such as aluminum (Al), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), gallium (Ga), zinc (Zn), indium (In), tin (Sn), molybdenum (Mo), tantalum (Ta), tungsten (W), palladium (Pd), gold (Au), platinum (Pt), silver (Ag), yttrium (Y), neodymium (Nd), and alloys containing these in appropriate combinations can also be used.

[0305] As the conductive layer 152, an oxide having one or more selected from indium, tin, zinc, gallium, titanium, aluminum, and silicon can be used. For example, it is preferable to use a conductive oxide containing one or more of the following: indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, zinc oxide containing gallium, titanium oxide, indium zinc oxide containing gallium, indium zinc oxide containing aluminum, indium tin oxide containing silicon, and indium zinc oxide containing silicon. In particular, indium tin oxide containing silicon has a large work function, for example, a work function of 4.0 eV or more, so it can be suitably used as the conductive layer 152.

[0306] The conductive layer 151 may be a laminated structure of multiple layers having different materials, and the conductive layer 152 may be a laminated structure of multiple layers having different materials. In this case, the conductive layer 151 may have a layer made of a material that can be used for the conductive layer 152, such as a conductive oxide, and the conductive layer 152 may have a layer made of a material that can be used for the conductive layer 151, such as a metallic material. For example, if the conductive layer 151 has a laminated structure of two or more layers, the layer in contact with the conductive layer 152 may be a layer made of a material that can be used for the conductive layer 152.

[0307] Furthermore, it is preferable that the end of the conductive layer 151 has a tapered shape. Specifically, it is preferable that the end of the conductive layer 151 has a tapered shape with a taper angle of less than 90°. In this case, the conductive layer 152 provided along the side surface of the conductive layer 151 also has a tapered shape. By making the side surface of the conductive layer 152 tapered, the coverage of the first layer 135 provided along the side surface of the conductive layer 152 can be improved.

[0308] This embodiment can be appropriately combined with other embodiments or examples. Furthermore, if multiple configuration examples are shown within a single embodiment in this specification, the configuration examples can be appropriately combined.

[0309] (Embodiment 5) This embodiment describes a display device according to one aspect of the present invention.

[0310] The display device of this embodiment can be a high-definition display device. Therefore, the display device of this embodiment can be used, for example, as a display unit for information terminals (wearable devices) such as wristwatches and bracelets, as well as as a display unit for wearable devices that can be worn on the head, such as VR devices such as head-mounted displays (HMDs) and AR devices such as glasses.

[0311] Furthermore, the display device of this embodiment can be a high-resolution display device or a large-screen display device. Therefore, the display device of this embodiment can be used in electronic devices with relatively large screens, such as television equipment, desktop or notebook personal computers, computer monitors, digital signage, and large game machines such as pachinko machines, as well as in the display units of digital cameras, digital video cameras, digital photo frames, mobile phones, portable game consoles, personal information terminals, and audio playback devices.

[0312] [Display Module] Figure 8A shows a perspective view of the display module 280. The display module 280 includes a display device 100A and an FPC 290. Note that the display device included in the display module 280 is not limited to the display device 100A, but may be any of the display devices 100B to 100E described later.

[0313] The display module 280 has substrates 291 and 292. The display module 280 has a display unit 281. The display unit 281 is an area in the display module 280 that displays an image, and is an area in which light from each pixel provided in the pixel unit 284, which will be described later, can be seen.

[0314] Figure 8B shows a schematic perspective view illustrating the configuration of the substrate 291. On the substrate 291, a circuit section 282, a pixel circuit section 283 on the circuit section 282, and a pixel section 284 on the pixel circuit section 283 are stacked. In addition, a terminal section 285 for connecting to the FPC 290 is provided in the portion of the substrate 291 that does not overlap with the pixel section 284. The terminal section 285 and the circuit section 282 are electrically connected by a wiring section 286, which is composed of multiple wires.

[0315] The pixel section 284 has a plurality of pixels 284a arranged periodically. An enlarged view of one pixel 284a is shown on the right side of Figure 8B. Various configurations described in the previous embodiment can be applied to the pixel 284a. Figure 8B shows an example where the pixel 284a has the same configuration as the pixel 178 shown in Figure 7.

[0316] The pixel circuit section 283 has a plurality of pixel circuits 283a arranged periodically.

[0317] One pixel circuit 283a is a circuit that controls the driving of multiple elements that a single pixel 284a has.

[0318] The circuit section 282 has circuits for driving each pixel circuit 283a of the pixel circuit section 283. For example, it is preferable to have one or both of a gate line drive circuit and a source line drive circuit. In addition, it may have at least one of the following: an arithmetic circuit, a memory circuit, and a power supply circuit.

[0319] The FPC 290 functions as wiring for supplying video signals or power potential, etc., to the circuit section 282 from an external source. An IC may also be mounted on the FPC 290.

[0320] The display module 280 can be configured such that one or both of the pixel circuit section 283 and the circuit section 282 are stacked on the lower side of the pixel section 284, thereby making it possible to achieve an extremely high aperture ratio (effective display area ratio) for the display section 281.

[0321] Because such a display module 280 is extremely high-resolution, it can be suitably used in VR devices such as HMDs or AR devices in the form of glasses. For example, even in a configuration where the display part of the display module 280 is viewed through lenses, the display module 280 has an extremely high-resolution display part 281, so even when the display part is magnified with lenses, pixels are not visible, enabling a highly immersive display. Furthermore, the display module 280 is not limited to this and can be suitably used in electronic devices having relatively small display parts.

[0322] [Display device 100A] The display device 100A shown in Figure 9A includes a substrate 301, a light-emitting device 130R, a light-emitting device 130G, a light-emitting device 130B, a capacitor 240, and a transistor 310.

[0323] The substrate 301 corresponds to the substrate 291 in Figures 8A and 8B. The transistor 310 is a transistor having a channel formation region in the substrate 301. As the substrate 301, a semiconductor substrate such as a single-crystal silicon substrate can be used. The transistor 310 has a part of the substrate 301, a conductive layer 311, a low-resistance region 312, an insulating layer 313, and an insulating layer 314. The conductive layer 311 functions as a gate electrode. The insulating layer 313 is located between the substrate 301 and the conductive layer 311 and functions as a gate insulating layer. The low-resistance region 312 is a region of the substrate 301 doped with impurities and functions as a source or drain. The insulating layer 314 is provided covering the side surface of the conductive layer 311.

[0324] Furthermore, an element isolation layer 315 is provided between two adjacent transistors 310 so as to be embedded in the substrate 301.

[0325] Furthermore, an insulating layer 261 is provided to cover the transistor 310, and a capacitance 240 is provided on the insulating layer 261.

[0326] The capacitor 240 has a conductive layer 241, a conductive layer 245, and an insulating layer 243 located between them. The conductive layer 241 functions as one electrode of the capacitor 240, the conductive layer 245 functions as the other electrode of the capacitor 240, and the insulating layer 243 functions as the dielectric of the capacitor 240.

[0327] The conductive layer 241 is provided on the insulating layer 261 and embedded in the insulating layer 254. The conductive layer 241 is electrically connected to either the source or drain of the transistor 310 by a plug 271 embedded in the insulating layer 261. The insulating layer 243 is provided covering the conductive layer 241. The conductive layer 245 is provided in the region that overlaps with the conductive layer 241 via the insulating layer 243.

[0328] An insulating layer 255 is provided covering the capacitance 240, an insulating layer 174 is provided on the insulating layer 255, and an insulating layer 175 is provided on the insulating layer 174. Light-emitting devices 130R, 130G, and 130B are provided on the insulating layer 175. An insulator is provided in the region between adjacent light-emitting devices.

[0329] An insulating layer 156R is provided so as to have a region that overlaps with the side surface of the conductive layer 151R, an insulating layer 156G is provided so as to have a region that overlaps with the side surface of the conductive layer 151G, and an insulating layer 156B is provided so as to have a region that overlaps with the side surface of the conductive layer 151B. Furthermore, a conductive layer 152R is provided so as to cover the conductive layer 151R and the insulating layer 156R, a conductive layer 152G is provided so as to cover the conductive layer 151G and the insulating layer 156G, and a conductive layer 152B is provided so as to cover the conductive layer 151B and the insulating layer 156B. A sacrificial layer 158R is located on the first layer 135R, a sacrificial layer 158G is located on the first layer 135G, and a sacrificial layer 158B is located on the first layer 135B.

[0330] The conductive layers 151R, 151G, and 151B are electrically connected to either the source or drain of the transistor 310 by the insulating layers 243, 255, 174, and plugs 256 embedded in the insulating layer 175, the conductive layer 241 embedded in the insulating layer 254, and plugs 271 embedded in the insulating layer 261. Various conductive materials can be used for the plugs.

[0331] Furthermore, a protective layer 131 is provided on the light-emitting devices 130R, 130G, and 130B. A substrate 120 is bonded to the protective layer 131 by a resin layer 122. Details of the components from the light-emitting devices 130 to the substrate 120 can be found in Embodiment 4. The substrate 120 corresponds to the substrate 292 in Figure 8A.

[0332] Figure 9B is a modified example of the display device 100A shown in Figure 9A. The display device shown in Figure 9B has a colored layer 132R, a colored layer 132G, and a colored layer 132B, and the light-emitting device 130 has a region that overlaps with one of the colored layers 132R, 132G, and 132B. In the display device shown in Figure 9B, the light-emitting device 130 can emit, for example, white light. Also, for example, the colored layer 132R can transmit red light, the colored layer 132G can transmit green light, and the colored layer 132B can transmit blue light.

[0333] [Display device 100B] Figure 10 shows a perspective view of the display device 100B, and Figure 11 shows a cross-sectional view of the display device 100C.

[0334] The display device 100B has a configuration in which substrate 352 and substrate 351 are bonded together. In Figure 10, substrate 352 is shown by a dashed line.

[0335] The display device 100B includes a pixel section 177, a connection section 140, a circuit 356, and wiring 355, etc. Figure 10 shows an example in which an IC 354 and an FPC 353 are mounted on the display device 100B. Therefore, the configuration shown in Figure 10 can also be called a display module having a display device 100B, an IC (integrated circuit), and an FPC. Here, a display module is a display device on which a connector such as an FPC is attached to the substrate, or on which an IC is mounted.

[0336] The connection portion 140 is provided on the outside of the pixel portion 177. There may be one or more connection portions 140. The connection portion 140 is electrically connected to the common electrode of the light-emitting device and the conductive layer, and can supply potential to the common electrode.

[0337] For example, a scan line drive circuit can be used as circuit 356.

[0338] The wiring 355 has the function of supplying signals and power to the pixel unit 177 and the circuit 356. These signals and power are input to the wiring 355 from an external source via the FPC 353 or from the IC 354.

[0339] Figure 10 shows an example in which IC 354 is provided on the substrate 351 using the COG (Chip On Glass) method or the COF (Chip On Film) method. IC 354 can be an IC having, for example, a scan line drive circuit or a signal line drive circuit. Note that the display device 100B and the display module may be configured without an IC. Alternatively, the IC may be mounted on the FPC, for example, using the COF method.

[0340] Figure 11 shows an example of a cross-section of the display device 100B when a portion of the area including the FPC 353, a portion of the circuit 356, a portion of the pixel portion 177, a portion of the connection portion 140, and a portion of the area including the end portion are cut.

[0341] [Display device 100C] The display device 100C shown in Figure 11 has a transistor 201, a transistor 205, a light-emitting device 130R that emits red light, a light-emitting device 130G that emits green light, and a light-emitting device 130B that emits blue light, etc., between the substrate 351 and the substrate 352.

[0342] Details of the light-emitting devices 130R, 130G, and 130B can be found in Embodiment 3.

[0343] Light-emitting device 130R has a conductive layer 224R, a conductive layer 151R on the conductive layer 224R, and a conductive layer 152R on the conductive layer 151R. Light-emitting device 130G has a conductive layer 224G, a conductive layer 151G on the conductive layer 224G, and a conductive layer 152G on the conductive layer 151G. Light-emitting device 130B has a conductive layer 224B, a conductive layer 151B on the conductive layer 224B, and a conductive layer 152B on the conductive layer 151B.

[0344] The conductive layer 224R is connected to the conductive layer 222b of the transistor 205 through an opening provided in the insulating layer 214. The end of the conductive layer 151R is located outside the end of the conductive layer 224R. The insulating layer 156R is provided so as to have a region in contact with the side surface of the conductive layer 151R, and the conductive layer 152R is provided so as to cover the conductive layer 151R and the insulating layer 156R.

[0345] The conductive layers 224G, 151G, 152G, and insulating layer 156G in the light-emitting device 130G, and the conductive layers 224B, 151B, 152B, and insulating layer 156B in the light-emitting device 130B are the same as the conductive layers 224R, 151R, 152R, and insulating layer 156R in the light-emitting device 130R, so a detailed explanation is omitted.

[0346] The conductive layer 224R, conductive layer 224G, and conductive layer 224B have recesses formed to cover the openings provided in the insulating layer 214. Layer 128 is embedded in these recesses.

[0347] Layer 128 has the function of flattening the recesses of conductive layers 224R, 224G, and 224B. Conductive layers 151R, 151G, and 151B are provided on conductive layers 224R, 224G, and 224B and on layer 128, and are electrically connected to conductive layers 224R, 224G, and 224B. Therefore, regions overlapping with the recesses of conductive layers 224R, 224G, and 224B can also be used as light-emitting regions, thereby increasing the aperture ratio of the pixels.

[0348] Layer 128 may be an insulating layer or a conductive layer. Various inorganic insulating materials, organic insulating materials, and conductive materials can be used for layer 128 as appropriate. In particular, it is preferable that layer 128 be formed using an insulating material, and especially preferable that it be formed using an organic insulating material. For example, an organic insulating material that can be used for the insulating layer 127 described above can be applied to layer 128.

[0349] A protective layer 131 is provided on the light-emitting devices 130R, 130G, and 130B. The protective layer 131 and the substrate 352 are bonded via an adhesive layer 142. A light-shielding layer 157 is provided on the substrate 352. A solid sealing structure or a hollow sealing structure can be applied to seal the light-emitting devices 130. In Figure 11, the space between the substrate 352 and the substrate 351 is filled with the adhesive layer 142, indicating a solid sealing structure. Alternatively, the space may be filled with an inert gas (such as nitrogen or argon), indicating a hollow sealing structure. In this case, the adhesive layer 142 may be provided in a frame shape so as not to overlap with the light-emitting devices. Furthermore, the space may be filled with a resin different from the adhesive layer 142 provided in a frame shape.

[0350] Figure 11 shows an example in which the connection portion 140 has a conductive layer 224C obtained by processing the same conductive film as conductive layers 224R, 224G, and 224B; a conductive layer 151C obtained by processing the same conductive film as conductive layers 151R, 151G, and 151B; and a conductive layer 152C obtained by processing the same conductive film as conductive layers 152R, 152G, and 152B. Figure 11 also shows an example in which an insulating layer 156C is provided so as to have a region that overlaps with the side surface of conductive layer 151C.

[0351] The display device 100B is a top-emission type. The light emitted by the light-emitting device is emitted towards the substrate 352. It is preferable to use a material with high transmittance to visible light for the substrate 352. If the light-emitting device emits infrared or near-infrared light, it is preferable to use a material with high transmittance to those. The first electrode (pixel electrode) contains a material that reflects visible light, and the second electrode (counter electrode) contains a material that transmits visible light.

[0352] On the substrate 351, insulating layers 211, 213, 215, and 214 are provided in this order. A portion of insulating layer 211 functions as a gate insulating layer for each transistor. A portion of insulating layer 213 functions as a gate insulating layer for each transistor. Insulating layer 215 is provided covering the transistors. Insulating layer 214 is provided covering the transistors and functions as a planarization layer. The number of gate insulating layers and insulating layers covering the transistors are not limited and may be a single layer or two or more layers, respectively.

[0353] It is preferable to use an inorganic insulating film as the insulating layer 211, insulating layer 213, and insulating layer 215.

[0354] An organic insulating layer is preferred for the insulating layer 214, which functions as a planarizing layer.

[0355] Transistors 201 and 205 have a conductive layer 221 that functions as a gate, an insulating layer 211 that functions as a gate insulating layer, conductive layers 222a and 222b that function as source and drain, a semiconductor layer 231, an insulating layer 213 that functions as a gate insulating layer, and a conductive layer 223 that functions as a gate.

[0356] A connection portion 204 is provided in the region of the substrate 351 that does not overlap with the substrate 352. At the connection portion 204, the wiring 355 is electrically connected to the FPC 353 via the conductive layer 166 and the connecting layer 242. The conductive layer 166 is shown as an example of a laminated structure consisting of a conductive film obtained by processing the same conductive film as conductive layers 224R, 224G, and 224B, a conductive film obtained by processing the same conductive film as conductive layers 151R, 151G, and 151B, and a conductive film obtained by processing the same conductive film as conductive layers 152R, 152G, and 152B. The conductive layer 166 is exposed on the upper surface of the connection portion 204. This allows the connection portion 204 and the FPC 353 to be electrically connected via the connecting layer 242.

[0357] It is preferable to provide a light-shielding layer 157 on the surface of the substrate 352 that faces the substrate 351. The light-shielding layer 157 can be provided between adjacent light-emitting devices, at connection points 140, and in circuits 356, etc. Various optical components can also be arranged on the outside of the substrate 352.

[0358] Materials suitable for use on substrate 120 can be applied to substrate 351 and substrate 352, respectively.

[0359] As the adhesive layer 142, a material that can be used for the resin layer 122 can be applied.

[0360] As the connecting layer 242, an anisotropic conductive film (ACF) or an anisotropic conductive paste (ACP) can be used.

[0361] [Display device 100D] The display device 100D shown in Figure 12 differs from the display device 100C shown in Figure 11 mainly in that it is a bottom-emission type display device.

[0362] The light emitted by the light-emitting device is emitted towards the substrate 351. It is preferable to use a material with high transmittance to visible light for the substrate 351. On the other hand, the light transmittance of the material used for the substrate 352 is not a requirement.

[0363] It is preferable to form a light-shielding layer 157 between the substrate 351 and the transistor 201, and between the substrate 351 and the transistor 205. Figure 12 shows an example in which a light-shielding layer 157 is provided on the substrate 351, an insulating layer 153 is provided on the light-shielding layer 157, and transistors 201, 205, etc. are provided on the insulating layer 153.

[0364] The light-emitting device 130R includes a conductive layer 112R, a conductive layer 126R on the conductive layer 112R, and a conductive layer 129R on the conductive layer 126R.

[0365] The light-emitting device 130B includes a conductive layer 112B, a conductive layer 126B on the conductive layer 112B, and a conductive layer 129B on the conductive layer 126B.

[0366] The conductive layers 112R, 112B, 126R, 126B, 129R, and 129B are made of materials with high transmittance to visible light. It is preferable to use a material that reflects visible light for the second electrode.

[0367] Although the light-emitting device 130G is not shown in Figure 12, it is also provided.

[0368] Furthermore, while Figure 12 and other figures show an example where the upper surface of layer 128 has a flat portion, the shape of layer 128 is not particularly limited.

[0369] [Display device 100E] The display device 100E shown in Figure 13 is a modified version of the display device 100C shown in Figure 11, and differs from the display device 100C mainly in that it has a colored layer 132R, a colored layer 132G, and a colored layer 132B.

[0370] In the display device 100E, the light-emitting device 130 has a region that overlaps with one of the colored layers 132R, 132G, and 132B. The colored layers 132R, 132G, and 132B can be provided on the substrate 351 side of the substrate 352. The edges of the colored layer 132R, the edges of the colored layer 132G, and the edges of the colored layer 132B can overlap with the light-shielding layer 157.

[0371] In the display device 100E, the light-emitting device 130 can emit, for example, white light. Also, for example, the colored layer 132R can transmit red light, the colored layer 132G can transmit green light, and the colored layer 132B can transmit blue light. The display device 100E may also be configured to have the colored layers 132R, 132G, and 132B placed between the protective layer 131 and the adhesive layer 142.

[0372] Figures 11 and 13 show examples where the upper surface of layer 128 has a flat portion, but the shape of layer 128 is not particularly limited.

[0373] This embodiment can be appropriately combined with other embodiments or examples. Furthermore, if multiple configuration examples are shown within a single embodiment in this specification, the configuration examples can be appropriately combined.

[0374] (Embodiment 6) This embodiment describes an electronic device according to one aspect of the present invention.

[0375] The electronic device of this embodiment has a display device according to one aspect of the present invention in its display unit. The display device according to one aspect of the present invention has low power consumption. Therefore, it can be used in the display units of various electronic devices.

[0376] Examples of electronic devices include television sets, desktop or notebook personal computers, computer monitors, digital signage, large game machines such as pachinko machines, and other electronic devices with relatively large screens, as well as digital cameras, digital video cameras, digital photo frames, mobile phones, portable game consoles, personal digital assistants, and audio playback devices.

[0377] In particular, a display device according to one aspect of the present invention consumes little power and is therefore suitable for use in relatively small electronic devices. Examples of such electronic devices include wristwatch-type and bracelet-type information terminals (wearable devices), as well as wearable devices that can be worn on the head, such as VR devices like head-mounted displays, AR devices like glasses, and MR devices.

[0378] The electronic device of this embodiment may have sensors (including those with functions to measure force, displacement, position, velocity, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared radiation).

[0379] An example of a wearable device that can be worn on the head will be explained using Figures 14A to 14D.

[0380] The electronic device 700A shown in Figure 14A and the electronic device 700B shown in Figure 14B each include a pair of display panels 751, a pair of housings 721, a communication unit (not shown), a pair of mounting units 723, a control unit (not shown), an imaging unit (not shown), a pair of optical members 753, a frame 757, and a pair of nose pads 758.

[0381] A display device according to one embodiment of the present invention can be applied to the display panel 751. Therefore, it is possible to create an electronic device that consumes little power and can be operated for a long time.

[0382] Electronic devices 700A and 700B can each project an image displayed on the display panel 751 onto the display area 756 of the optical element 753. Because the optical element 753 is translucent, the user can see the image displayed on the display area superimposed on the transmitted image visible through the optical element 753.

[0383] Electronic devices 700A and 700B may be equipped with cameras capable of capturing images of the area in front of them as imaging units. Furthermore, electronic devices 700A and 700B may each be equipped with acceleration sensors such as gyro sensors to detect the orientation of the user's head and display an image corresponding to that orientation in the display area 756.

[0384] The communications unit has a wireless communication device, which can supply, for example, a video signal. Alternatively, instead of the wireless communication device, or in addition to the wireless communication device, it may be equipped with a connector to which a cable for supplying video signals and power potential can be connected.

[0385] Furthermore, electronic devices 700A and 700B are equipped with batteries that can be charged wirelessly, wired, or both.

[0386] The housing 721 may also be provided with a touch sensor module.

[0387] Various types of touch sensors can be used in the touch sensor module. For example, various methods such as capacitive, resistive, infrared, electromagnetic induction, surface acoustic wave, or optical sensors can be employed. In particular, it is preferable to apply capacitive or optical sensors to the touch sensor module.

[0388] The electronic device 800A shown in Figure 14C and the electronic device 800B shown in Figure 14D each include a pair of display units 820, a housing 821, a communication unit 822, a pair of mounting units 823, a control unit 824, a pair of imaging units 825, and a pair of lenses 832.

[0389] A display device according to one embodiment of the present invention can be applied to the display unit 820. Therefore, it is possible to create an electronic device that consumes little power and can be operated for a long time.

[0390] The display unit 820 is located inside the housing 821 in a position visible through the lens 832. Furthermore, by displaying different images on a pair of display units 820, a three-dimensional display using parallax can be achieved.

[0391] Preferably, electronic devices 800A and 800B have a mechanism that allows the left and right positions of the lens 832 and the display unit 820 to be in an optimal position according to the user's eye position.

[0392] The attachment portion 823 allows the user to attach the electronic device 800A or the electronic device 800B to their head.

[0393] The imaging unit 825 has the function of acquiring external information. The data acquired by the imaging unit 825 can be output to the display unit 820. An image sensor can be used in the imaging unit 825. In addition, multiple cameras may be provided to accommodate multiple angles of view, such as telephoto and wide-angle.

[0394] The electronic device 800A may have a vibration mechanism that functions as a bone conduction earphone.

[0395] Electronic devices 800A and 800B may each have input terminals. Cables can be connected to the input terminals to supply video signals from video output devices, etc., and power for charging batteries provided in the electronic devices.

[0396] An electronic device according to one aspect of the present invention may have a function for wireless communication with an earphone 750.

[0397] Furthermore, the electronic device may have an earphone section. The electronic device 700B shown in Figure 14B has an earphone section 727. Some of the wiring connecting the earphone section 727 and the control unit may be located inside the housing 721 or the mounting section 723.

[0398] Similarly, the electronic device 800B shown in Figure 14D has an earphone unit 827. For example, the earphone unit 827 and the control unit 824 can be connected to each other by a wire.

[0399] Thus, as one embodiment of the present invention, both eyeglass-type (electronic devices 700A and 700B, etc.) and goggle-type (electronic devices 800A and 800B, etc.) are preferred as electronic devices.

[0400] The electronic device 6500 shown in Figure 15A is a portable information terminal that can be used as a smartphone.

[0401] The electronic device 6500 includes a housing 6501, a display unit 6502, a power button 6503, a button 6504, a speaker 6505, a microphone 6506, a camera 6507, and a light source 6508, etc. The display unit 6502 has a touch panel function.

[0402] A display device according to one embodiment of the present invention can be applied to the display unit 6502. Therefore, an electronic device with low power consumption and long operating time can be made.

[0403] Figure 15B is a schematic cross-sectional view of the housing 6501 including the end on the microphone 6506 side.

[0404] A light-transmitting protective member 6510 is provided on the display side of the housing 6501, and the display panel 6511, optical member 6512, touch sensor panel 6513, printed circuit board 6517, and battery 6518 are arranged in the space enclosed by the housing 6501 and the protective member 6510.

[0405] The protective member 6510 is fixed to the display panel 6511, the optical member 6512, and the touch sensor panel 6513 by an adhesive layer (not shown).

[0406] In the area outside the display unit 6502, a portion of the display panel 6511 is folded back, and the FPC 6515 is connected to this folded portion. IC 6516 is mounted on the FPC 6515. The FPC 6515 is connected to terminals provided on the printed circuit board 6517.

[0407] A display device according to one embodiment of the present invention can be applied to the display panel 6511. This makes it possible to realize an extremely lightweight electronic device. Furthermore, because the display panel 6511 is extremely thin, it is possible to incorporate a large-capacity battery 6518 while keeping the thickness of the electronic device low. In addition, by folding back a part of the display panel 6511 and placing the connection part with the FPC 6515 on the back of the pixel section, an electronic device with a narrow bezel can be realized.

[0408] Figure 15C shows an example of a television system. The television system 7100 has a display unit 7000 incorporated into a housing 7171. Here, the housing 7171 is shown supported by a stand 7173.

[0409] A display device according to one aspect of the present invention can be applied to the display unit 7000. Therefore, an electronic device with low power consumption and long operating time can be made.

[0410] The television device 7100 shown in Figure 15C can be operated using the operation switches on the housing 7171 and a separate remote control unit 7151.

[0411] Figure 15D shows an example of a notebook personal computer. The notebook personal computer 7200 has a casing 7211, a keyboard 7212, a pointing device 7213, and an external connection port 7214, etc. A display unit 7000 is incorporated into the casing 7211.

[0412] A display device according to one aspect of the present invention can be applied to the display unit 7000. Therefore, an electronic device with low power consumption and long operating time can be made.

[0413] Figures 15E and 15F show examples of digital signage.

[0414] The digital signage 7300 shown in Figure 15E includes a housing 7301, a display unit 7000, and a speaker 7303, etc. Furthermore, it may include LED lamps, operation keys (including a power switch or operation switch), connection terminals, various sensors, a microphone, etc.

[0415] Figure 15F shows a digital signage 7400 mounted on a cylindrical column 7401. The digital signage 7400 has a display unit 7000 that is provided along the curved surface of the column 7401.

[0416] In Figures 15E and 15F, a display device according to one embodiment of the present invention can be applied to the display unit 7000. Therefore, a highly reliable electronic device can be made.

[0417] The larger the display area 7000, the more information can be provided at once. Furthermore, a larger display area 7000 is more eye-catching, which can, for example, enhance the effectiveness of advertising.

[0418] Furthermore, as shown in Figures 15E and 15F, it is preferable that the digital signage 7300 or digital signage 7400 can be linked wirelessly with an information terminal device 7311 or information terminal device 7411 such as a smartphone owned by the user.

[0419] The electronic device shown in Figures 16A to 16G includes a housing 9000, a display unit 9001, a speaker 9003, operation keys 9005 (including a power switch or operation switch), connection terminals 9006, a sensor 9007 (including a function to measure force, displacement, position, velocity, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared radiation), a microphone 9008, and the like.

[0420] The electronic devices shown in Figures 16A to 16G have various functions. For example, they can have functions to display various information (still images, videos, text images, etc.) on a display unit, a touch panel function, a function to display a calendar, date or time, a function to control processing by various software (programs), a wireless communication function, a function to read and process programs or data recorded on a recording medium, and so on.

[0421] Details of the electronic equipment shown in Figures 16A to 16G will be explained below.

[0422] Figure 16A is a perspective view showing a personal digital information terminal (PDI) 9171. The PDI 9171 can be used, for example, as a smartphone. The PDI 9171 may also be equipped with a speaker 9003, a connection terminal 9006, or a sensor 9007. Furthermore, the PDI 9171 can display text and image information on multiple surfaces. Figure 16A shows an example where three icons 9050 are displayed. Information 9051, indicated by a dashed rectangle, can also be displayed on other surfaces of the display unit 9001. Examples of information 9051 include notifications of incoming emails, SNS messages, phone calls, etc., the title of emails or SNS messages, the sender's name, date and time, time, battery level, signal strength, etc. Alternatively, icons 9050, etc., may be displayed in the position where the information 9051 is displayed.

[0423] Figure 16B is a perspective view showing the personal digital assistant (PDA) 9172. The PDA 9172 has the function of displaying information on three or more sides of the display unit 9001. Here, an example is shown in which information 9052, information 9053, and information 9054 are displayed on different sides. For example, a user can check information 9053, which is displayed in a position that can be observed from above the PDA 9172, while the PDA 9172 is stored in the breast pocket of their clothing.

[0424] Figure 16C is a perspective view showing the tablet terminal 9173. The tablet terminal 9173 can run various applications, such as mobile phone calls, email, document viewing and creation, music playback, internet communication, and computer games. The tablet terminal 9173 has a display unit 9001, a camera 9002, a microphone 9008, and a speaker 9003 on the front of the housing 9000. The left side of the housing 9000 has operation keys 9005 as buttons for operation, and the bottom has connection terminals 9006.

[0425] Figure 16D is a perspective view showing a wristwatch-type personal information terminal 9200. The personal information terminal 9200 can be used, for example, as a smartwatch (registered trademark). The display unit 9001 has a curved display surface, allowing it to display information along the curved surface. The personal information terminal 9200 can also make hands-free calls by communicating with, for example, a wireless communication headset. Furthermore, the personal information terminal 9200 can transmit data to other information terminals and be charged via a connection terminal 9006. Charging may be performed by wireless power supply.

[0426] Figures 16E to 16G are perspective views showing a foldable portable information terminal 9201. Figure 16E shows the portable information terminal 9201 in an unfolded state, Figure 16G shows it in a folded state, and Figure 16F shows a perspective view of the state in between, transitioning from one of Figures 16E or 16G to the other. The portable information terminal 9201 offers excellent portability in its folded state and excellent readability of the display due to its seamless, wide display area in its unfolded state. The display unit 9001 of the portable information terminal 9201 is supported by three housings 9000 connected by hinges 9055. For example, the display unit 9001 can be bent with a radius of curvature of 0.1 mm to 150 mm.

[0427] This embodiment can be appropriately combined with other embodiments or examples. Furthermore, if multiple configuration examples are shown within a single embodiment in this specification, the configuration examples can be appropriately combined.

[0428] (Synthesis Example 1) This example describes the physical properties and synthesis method of an organic compound according to one embodiment of the present invention. Specifically, the synthesis method of N,N'-bis[3,5-di(2-adamantyl)phenyl]-N,N'-bis(3,5-di-tert-butylphenyl)pyrene-1,6-diamine (abbreviated as 1,6mmAdtBuDPhAPrn), shown by structural formula (101) in Embodiment 1, will be described. The structure of 1,6mmAdtBuDPhAPrn is shown below.

[0429]

[0430] <Step 1: Synthesis of 1,6mmAdtBuDPhAPrn> 0.35 g (0.97 mmol) of 1,6-dibromopyrene, 1.1 g (2.0 mmol) of 3,5-bis(2-adamantyl)-3',5'-di-tert-butyldiphenylamine, and 0.38 g (4.0 mmol) of sodium-tert-butoxide were added to a 200 mL three-necked flask, and the flask was purged with nitrogen. 10 mL of xylene was added to this mixture, and the mixture was degassed under reduced pressure. Then, 0.3 mL (96 μmol) of tri-tert-butylphosphine (10% hexane solution) and 20 mg (35 μmol) of bis(dibenzylideneacetone)palladium (0) were added to the mixture, and the mixture was stirred at 150 °C for 6 hours under a nitrogen stream.

[0431] After stirring, 300 mL of heated toluene was added to the mixture, and then the mixture was filtered by suction through Celite (Fujifilm Wako Pure Chemical Industries, Ltd., catalog number: 537-02305), Florizil (Fujifilm Wako Pure Chemical Industries, Ltd., catalog number: 066-05265), and aluminum oxide to obtain the filtrate.

[0432] The obtained filtrate was concentrated, and the resulting solid was purified by silica gel chromatography to obtain a pale yellow solid.

[0433] The obtained solid was recrystallized with toluene, yielding 0.55 g of the target pale yellow solid in a yield of 44%. The synthesis scheme for Step 1 is shown below (a-1).

[0434]

[0435] Furthermore, 0.55 g of the obtained pale yellow solid was purified by sublimation using the train sublimation method. Sublimation purification was performed at a pressure of 4.8 × 10⁻⁶. −２ Under Pa conditions, the pale yellow solid was heated at 360°C for 15 hours. After sublimation purification, the target pale yellow solid was obtained in a yield of 0.46 g with a recovery rate of 84%.

[0436] The resulting pale yellow solid is deuterated chloroform (abbreviated as CDCl). ３ The measurement results for the solution are shown below. １The 1H NMR spectra are shown in Figures 17A, 17B, and 17C. Figure 17B is an enlarged view of the 6.0 ppm to 8.5 ppm range in Figure 17A. Figure 17C is an enlarged view of the 0.5 ppm to 3.5 ppm range in Figure 17A. Furthermore, the pale yellow solid... １ The measurement results by 1H NMR are shown below. From these results, it was found that 1,6 mm AdtBuDPhAPrn was obtained by this synthesis method.

[0437] １ 1H NMR (CDCl ３ , 300MHz): δ = 8.05-7.96 (m, 4H), 7.81-7.74 (m, 4H), 7.00-6.86 (m, 12H), 2.89 (bs, 4H) ), 2.22 (bs, 8H), 1.87-1.84 (m, 20H), 1.67 (m, 20H), 1.35-1.32 (m, 8H), 1.17 (s, 36H).

[0438] Next, the absorption and emission spectra of a toluene solution containing 1.6 mm AdtBuDPhAPrn were measured. The ultraviolet-visible absorption spectrum (hereinafter simply referred to as "absorption spectrum") and emission spectrum were measured. A UV-Vis near-infrared spectrophotometer (V-770DS, JASCO Corporation) was used to measure the absorption spectrum. A spectrofluorometer (FP-8600DS, JASCO Corporation) was used to measure the emission spectrum. The measurement results of the absorption and emission spectra of the obtained toluene solution are shown in Figure 18. The horizontal axis represents wavelength, and the vertical axis represents absorption intensity.

[0439] Figure 18 shows that a toluene solution of 1,6 mmAdtBuDPhAPrn exhibited a peak at a wavelength around 444 nm in its absorption spectrum and a peak at a wavelength of 471 nm (excitation wavelength 400 nm) in its emission spectrum. Therefore, it was found that 1,6 mmAdtBuDPhAPrn exhibits a blue emission color.

[0440] (Synthesis Example 2) This example describes the physical properties and synthesis method of an organic compound according to one embodiment of the present invention. Specifically, the synthesis method of N,N'-bis(3,5-dicyclohexylphenyl)-N,N'-bis(3,5-di-tert-butylphenyl)pyrene-1,6-diamine (abbreviated as 1,6mmchtBuDPhAPrn), shown by structural formula (100) in Embodiment 1, will be described. The structure of 1,6mmchtBuDPhAPrn is shown below.

[0441]

[0442] <Step 1: Synthesis of 1,6mmchtBuDPhAPrn> 1.0 g (2.8 mmol) of 1,6-dibromopyrene, 2.6 g (5.8 mmol) of 3,5-dicyclohexyl-3',5'-di-tert-butyldiphenylamine, and 1.1 g (11 mmol) of sodium-tert-butoxide were added to a 200 mL three-necked flask, and the flask was purged with nitrogen. 30 mL of xylene was added to this mixture, and the mixture was degassed under reduced pressure. Then, 0.6 mL (0.19 mmol) of tri-tert-butylphosphine (10% hexane solution) and 40 mg (70 μmol) of bis(dibenzylideneacetone)palladium (0) were added to the mixture, and the mixture was stirred at 150 °C for 6 hours under a nitrogen stream.

[0443] After stirring, 300 mL of heated toluene was added to the mixture, and then the mixture was filtered by suction through Celite (Fujifilm Wako Pure Chemical Industries, Ltd., catalog number: 537-02305), Florizil (Fujifilm Wako Pure Chemical Industries, Ltd., catalog number: 066-05265), and aluminum oxide to obtain the filtrate.

[0444] The obtained filtrate was concentrated, and the resulting solid was recrystallized with toluene to obtain 2.8 g of the target product as a pale yellow solid in a yield of 92%. The synthesis scheme for Step 1 is shown below (b-1).

[0445]

[0446] Furthermore, 2.5 g of the obtained pale yellow solid was purified by sublimation using the train sublimation method. Sublimation purification was carried out by heating the pale yellow solid at 310°C for 15 hours under conditions of a pressure of 4.7 Pa. After sublimation purification, the target pale yellow solid was obtained in a yield of 2.3 g with a recovery rate of 92%.

[0447] The resulting pale yellow solid is deuterated chloroform (abbreviated as CDCl). ３ The measurement results for the solution are shown below. １ The 1H NMR spectra are shown in Figures 19A, 19B, and 19C. Figure 19B is an enlarged view of the 6 ppm to 8.5 ppm range in Figure 19A. Figure 19C is an enlarged view of the 0.5 ppm to 3.5 ppm range in Figure 19A. Furthermore, the pale yellow solid... １ The measurement results by 1H NMR are shown below. From these results, it was found that 1,6 mmchtBuDPhAPrn was obtained.

[0448] １ 1H NMR (CDCl ３ , 300MHz): δ = 8.11-8.03 (m, 4H), 7.88-7.80 (m, 4H), 6.98-6.63 (m, 12H), 2.30 (m, 4H), 1.76-1.58 (m, 20H), 1.35-1.16 (m, 56H).

[0449] Next, the absorption and emission spectra of a toluene solution containing 1,6 mmchtBuDPhAPrn were measured. A UV-Vis-Near-Infrared spectrophotometer (V-770DS, JASCO Corporation) was used to measure the absorption spectrum. A spectrofluorometer (FP-8600DS, JASCO Corporation) was used to measure the emission spectrum. The results of the absorption and emission spectra measurements for the toluene solution are shown in Figure 20. The horizontal axis represents wavelength, and the vertical axis represents absorption intensity.

[0450] Figure 20 shows that a toluene solution of 1,6 mmchtBuDPhAPrn exhibits a peak in its absorption spectrum at a wavelength around 441 nm and a peak in its emission spectrum at a wavelength of 469 nm (excitation wavelength 410 nm). Therefore, it was found that 1,6 mmchtBuDPhAPrn exhibits a blue emission color.

[0451] In this example, the detailed manufacturing method and characteristics of light-emitting devices 1-1 and 1-2 will be described. The structural formulas of the main compounds used in this example are shown below.

[0452]

[0453] (Method for fabricating light-emitting device 1-1) First, indium tin oxide (ITSO) containing silicon oxide was layered onto a glass substrate by sputtering to a thickness of 70 nm, forming a first electrode 101 with dimensions of 2 mm x 2 mm. The ITSO functions as an anode.

[0454] Next, as a pretreatment for forming a light-emitting device on the substrate, the substrate surface was washed with water.

[0455] After that, approximately 1 x 10 −４ The substrate was introduced into a vacuum deposition apparatus where the internal pressure was reduced to Pa. After vacuum firing at 170°C for 30 minutes in the heating chamber of the vacuum deposition apparatus, the substrate was allowed to cool for approximately 30 minutes.

[0456] Next, the substrate was fixed to a holder provided in a vacuum deposition apparatus so that the surface on which the first electrode 101 was formed was facing downwards. A hole injection layer 111 was then formed by co-depositing N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviated as PCBBiF), represented by the above structural formula (i), and an electron acceptor material (OCHD-003) containing fluorine with a molecular weight of 672, on the inorganic insulating film and the first electrode 101 in a weight ratio of 1:0.03 (= PCBBiF:OCHD-003) with a film thickness of 10 nm.

[0457] After depositing PCBiF onto the hole injection layer 111 to a thickness of 30 nm, 9-[3-(triphenylsilyl)phenyl]-3,9'-bi-9H-carbazole (abbreviated as PSiCzCz), represented by the above structural formula (ii), was deposited to a thickness of 5 nm to form a hole transport layer 112.

[0458] Next, on the hole transport layer, 9,9'-{6-[3-(triphenylsilyl)phenyl]-1,3,5-triazine-2,4-diyl}bis(9H-carbazole) (abbreviated as SiTrzCz2), represented by the above structural formula (iii), PSiCzCz, and (2-{3-[3-(3,5-di-tert-butylphenyl)benzimidazole-1-yl-2-ylidene-κC2]phenoxy-κC2}-9-(4-tert-butyl-2-pyridinyl-κN)carbazole-2,1-diyl A light-emitting layer 113 was formed by co-depositing platinum(II) (abbreviated as PtON-TBBI) (κC1) and N,N'-bis(3,5-di-tert-butylphenyl)pyrene-1,6-diamine (abbreviated as 1,6mmchtBuDPhAPrn), represented by the above structural formula (v), in a weight ratio of 0.35:0.53:0.12:0.015 (=SiTrzCz2:PSiCzCz:PtON-TBBI:1,6mmchtBuDPhAPrn) with a film thickness of 35 nm.

[0459] Next, 2-phenyl-4,6-bis[3-(triphenylsilyl)phenyl]-1,3,5-triazine (abbreviated as mSiTrz), represented by the above structural formula (vi), was deposited to a thickness of 5 nm to form a first electron transport layer. Then, 11-[4-(biphenyl-4-yl)-6-phenyl-1,3,5-triazine-2-yl]-11,12-dihydro-12-phenylindoro[2,3-a]carbazole (abbreviated as BP-Icz(II)TZn), represented by the above structural formula (vii), and 8-quinolinolato-lithium (abbreviated as Liq), represented by the above structural formula (viii), were co-deposited in a weight ratio of 1:4 (=BP-Icz(II)TZn:Liq) to a thickness of 30 nm to form a second electron transport layer.

[0460] After the electron transport layer was formed, lithium fluoride (abbreviated as LiF) was deposited to a thickness of 1 nm to form an electron injection layer 115, and then aluminum (abbreviated as Al) was deposited to a thickness of 200 nm to form a second electrode 102 (cathode).

[0461] Next, in a glove box under a nitrogen atmosphere, the light-emitting device was sealed with a glass substrate to prevent exposure to the atmosphere (applying a UV-curable sealant around the element, irradiating only the sealant with UV light without irradiating the light-emitting device, and heat-treating at 80°C for 1 hour under atmospheric pressure) to form the light-emitting device 1-1.

[0462] (Method for fabricating light-emitting devices 1-2) Light-emitting devices 1-2 were fabricated in the same manner as light-emitting devices 1-1, except that 1,6 mmchtBuDPhAPrn in the light-emitting layer of light-emitting device 1-1 was replaced with N,N'-bis[3,5-di(2-adamantyl)phenyl]-N,N'-bis(3,5-di-tert-butylphenyl)pyrene-1,6-diamine (abbreviated as 1,6 mmAdtBuDPhAPrn), which is represented by the above structural formula (ix).

[0463] The device structures of light-emitting device 1-1 and light-emitting device 1-2 are shown in the table below.

[0464]

[0465] Figure 21 shows the luminance-current density characteristics of light-emitting devices 1-1 and 1-2, Figure 22 shows the luminance-voltage characteristics, Figure 23 shows the current efficiency-current density characteristics, Figure 24 shows the current density-voltage characteristics, Figure 25 shows the blue index-current density characteristics, Figure 26 shows the external quantum efficiency-current density characteristics, Figure 27 shows the field emission spectrum, and Figure 28 shows the CIE chromaticity coordinate diagram. Furthermore, the luminance is 1000 cd / m². ２ Table 2 shows the main characteristics of the device. A spectroradiometer (Topcon SR-UL1R) was used to measure luminance, CIE chromaticity, and field emission spectrum at room temperature. The external quantum efficiency was calculated using the measured luminance and emission spectrum, assuming a Lambertsian light distribution pattern.

[0466] The Blue Index (BI) is a value obtained by dividing the current efficiency (cd / A) by the y value of the CIE(x,y) chromaticity, and is one of the indicators that represent the emission characteristics of blue light. Blue light tends to have higher color purity as the chromaticity y value decreases. By using blue light with a small chromaticity y value and high color purity, it becomes possible to express a wide range of blue colors in a display, and the brightness of blue required to express white in the display decreases, resulting in the effect of reducing the power consumption of the display. For this reason, the BI, which is a current efficiency that takes into account the chromaticity y value, one of the indicators of blue purity, is sometimes suitably used as a means of representing the efficiency of blue light emission, and it can be said that light-emitting devices with a high BI are more efficient as blue light-emitting devices used in displays.

[0467]

[0468] From Figures 21 to 28 and Table 2, it was found that light-emitting devices 1-1 and 1-2 are blue light-emitting devices with good current efficiency, external quantum efficiency, and BI, and high luminous efficiency.

[0469] Here, Figures 29 and 30 show the measurement results of the emission spectra (PL spectra) and absorption spectra of PtON-TBBI, a material capable of converting the triplet excitation energy in the fabricated light-emitting device 1 and comparative light-emitting device 1-1 into light emission, and the fluorescent light-emitting materials 1,6 mmchtBuDPhAPrn or 1,6 mmAdtBuDPhAPrn. Note that the emission spectrum of PtON-TBBI was measured in a dichloromethane solution using a spectrofluorometer (FP-8600DS, JASCO Corporation), and the absorption spectrum was measured using a UV-Vis spectrofluorometer (V-770DS, JASCO Corporation). Furthermore, the emission spectra of 1,6 mm chtBuDPhAPrn and 1,6 mm AdtBuDPhAPrn were measured in toluene solution using a fluorometer (Hamamatsu Photonics FS920), and the absorption spectra were measured using a UV-Vis spectrofluorometer (JASCO V-550DS).

[0470] As shown in Figure 29, the peak wavelength (456 nm) in the emission spectrum of PtON-TBBI is at a shorter wavelength than the peak wavelength (469 nm) in the emission spectrum of 1,6 mm chtBuDPhAPrn. Also, as shown in Figure 30, the peak wavelength (456 nm) in the emission spectrum of PtON-TBBI is at a shorter wavelength than the peak wavelength (471 nm) in the emission spectrum of 1,6 mm AdtBuDPhAPrn. Furthermore, the wavelength of the short-wavelength emission edge (441 nm) in the emission spectrum of PtON-TBBI is at a shorter wavelength than the wavelength of the short-wavelength emission edge (449 nm) in the emission spectrum of 1,6 mm chtBuDPhAPrn. Furthermore, the wavelength of the short-wavelength emission edge in the emission spectrum of PtON-TBBI (441 nm) is shorter than the wavelength of the short-wavelength emission edge in the emission spectrum of 1,6 mm AdtBuDPhAPrn (450 nm). Also, the wavelength of the short-wavelength emission edge in the emission spectrum of PtON-TBBI (441 nm) is shorter than the wavelength of the long-wavelength absorption edge in the absorption spectrum of 1,6 mm AdtBuDPhAPrn (466 nm). Furthermore, the wavelength of the short-wavelength emission edge in the emission spectrum of PtON-TBBI (441 nm) is shorter than the wavelength of the long-wavelength absorption edge in the absorption spectrum of 1,6 mm AdtBuDPhAPrn (469 nm). In a light-emitting device 1 or light-emitting device 1-2 having such a configuration, energy transfer occurs efficiently from PtON-TBBI, a material capable of converting triplet excitation energy into light emission in the light-emitting layer, to the fluorescent material 1,6 mmchtBuDPhAPrn or 1,6 mmAdtBuDPhAPrn. This configuration allows for a light-emitting device that exhibits high luminescence efficiency while still being a device in which the fluorescent material emits light.

[0471] Figure 27 shows that the peak wavelength of light-emitting device 1-1 is 470 nm and the full width at half maximum is 50 nm, while the peak wavelength of light-emitting device 1-2 is 472 nm and the full width at half maximum is 52 nm. This indicates that light-emitting devices 1-1 and 1-2 emit light from the fluorescent materials 1,6 mmchtBuDPhAPrn and 1,6 mmAdtBuDPhAPrn.

[0472] Furthermore, as shown in Figure 26, despite the fact that the light-emitting devices 1-1 and 1-2 emit light from a fluorescent material as described above, they exhibit an external quantum efficiency of over 15%, and in particular, light-emitting device 1-1 shows an excellent value of up to 20% external quantum efficiency. Thus, by using the phosphorescent material PtON-TBBI as an energy donor, light-emitting devices 1-1 and 1-2 were made into light-emitting devices that exhibit high efficiency, with an external quantum efficiency of over 15%, despite being fluorescent light-emitting devices.

[0473] As described above, the light-emitting devices 1-1 and 1-2 according to one aspect of the present invention are configured to emit light from a fluorescent material. Compared to phosphorescent materials, fluorescent materials have a faster emission rate constant and a shorter excited state lifetime, thus providing high stability against degradation. Furthermore, the energy transfer rate when the excitation energy of the phosphorescent material is transferred to the fluorescent material exceeds the emission rate of the phosphorescent material, thus increasing stability against degradation and improving reliability.

[0474] Furthermore, in light-emitting devices 1-1 and 1-2, the fluorescent material emits light through energy transfer from the phosphorescent material. In this process, because the fluorescent material has a protecting group, energy transfer via the Dexter mechanism is suppressed, and energy transfer via the Förster mechanism becomes dominant. This suppresses triplet excitation energy transfer from the T1 level of the phosphorescent material to the T1 level (non-luminescent) of the fluorescent material, thus preventing a decrease in luminescence efficiency. As a result, despite being a light-emitting device that obtains light from a fluorescent material, it becomes a light-emitting device with good luminescence efficiency, with an external quantum efficiency exceeding 15%.

[0475] Furthermore, in 1,6mmchtBuDPhAPrn and 1,6mmAdtBuDPhAPrn, the cyclohexyl and adamantyl protecting groups have a bulky structure, resulting in a long distance between the pyrene skeleton (the luminescent phosphodiester) and the tips of these protecting groups. This effectively suppresses energy transfer via the Dexter mechanism, leading to a dominance of energy transfer via the Förster mechanism. As a result, triplet excitation energy transfer from the T1 level of the phosphorescent material to the T1 level (non-luminescent) of the fluorescent material is more effectively suppressed, thus preventing a decrease in luminescence efficiency. This is one of the reasons why a light-emitting device according to one aspect of the present invention has become a light-emitting device with excellent properties, exhibiting an external quantum efficiency exceeding 15%.

[0476] Thus, a light-emitting device according to one aspect of the present invention can be a light-emitting device with high luminous efficiency, high reliability, and good characteristics.

[0477] 100: Display device, 100A: Display device, 100B: Display device, 100C: Display device, 100D: Display device, 100E: Display device, 101: First electrode, 101R: First electrode, 101G: First electrode, 101B: First electrode, 102: Second electrode, 103: Organic compound layer, 110: Sub-pixel, 110B: Sub-pixel, 110G: Sub-pixel, 110R: Sub-pixel, 111: Hole injection layer, 112: Hole transport layer, 112B: Conductive layer, 112R: Conductive layer, 113: Light-emitting layer, 114: Electron transport layer, 115: Electron injection layer, 116: Charge generation layer, 117: p-type layer, 118: Electron 119: Relay layer, 120: Electron injection buffer layer, 122: Substrate, 124: Resin layer, 124: Fluorescent material, 124a: Luminescent group, 125: Inorganic insulating layer, 126B: Conductive layer, 126R: Conductive layer, 127: Insulating layer, 128: Layer, 129B: Conductive layer, 129R: Conductive layer, 130: Light-emitting device, 130B: Light-emitting device, 130G: Light-emitting device, 130R: Light-emitting device, 131: Protective layer, 132B: Colored layer, 132G: Colored layer, 132R: Colored layer, 135: First layer, 135A: First layer group, 135B: First layer, 135G: First layer, 135R: First layer, 136 : Common layer, 140: Connection part, 141: Region, 142: Adhesive layer, 151: Conductive layer, 151B: Conductive layer, 151C: Conductive layer, 151G: Conductive layer, 151R: Conductive layer, 152: Conductive layer, 152B: Conductive layer, 152C: Conductive layer, 152G: Conductive layer, 152R: Conductive layer, 153: Insulating layer, 156B: Insulating layer, 156C: Insulating layer, 156G: Insulating layer, 156R: Insulating layer, 157: Light-shielding layer, 158B: Sacrificial layer, 158G: Sacrificial layer, 158R: Sacrificial layer, 166: Conductive layer, 171: Insulating layer, 172: Conductive layer, 173: Insulating layer, 174: Insulating layer, 175: Insulating layer, 176: Plastic 177: Pixel section, 178: Pixel, 201: Transistor, 204: Connection section, 205: Transistor, 211: Insulating layer, 213: Insulating layer, 214: Insulating layer, 215: Insulating layer, 221: Conductive layer, 222a: Conductive layer, 222b: Conductive layer, 223: Conductive layer, 224B: Conductive layer, 224C: Conductive layer, 224G: Conductive layer, 224R: Conductive layer, 231: Semiconductor layer, 240: Capacitor, 241: Conductive layer, 242: Connection layer, 243: Insulating layer, 245: Conductive layer, 254: Insulating layer, 255: Insulating layer, 256: Plug, 261: Insulating layer, 271: Plug, 280: Display module281: Display unit, 282: Circuit unit, 283: Pixel circuit unit, 283a: Pixel circuit, 284: Pixel unit, 284a: Pixel, 285: Terminal unit, 286: Wiring unit, 290: FPC, 291: Substrate, 292: Substrate, 301: Substrate, 310: Transistor, 311: Conductive layer, 312: Low-resistance region, 313: Insulating layer, 314: Insulating layer, 315: Element isolation layer, 331: Compound, 332: Compound, 332a: Light luminescent group, 332b: Protecting group, 333: Compound, 334: Compound, 351: Substrate, 352: Substrate, 353: FPC, 354: IC, 355: Wiring, 356: Circuit, 501: 502: First electrode, 511: Second electrode, 512: First light-emitting unit, 513: Second light-emitting unit, 700A: Electronic equipment, 700B: Electronic equipment, 721: Housing, 723: Mounting part, 727: Earphone part, 750: Earphone, 751: Display panel, 753: Optical component, 756: Display area, 757: Frame, 758: Nose pad, 800A: Electronic equipment, 800B: Electronic equipment, 820: Display part, 821: Housing, 822: Communication part, 823: Mounting part, 824: Control unit, 825: Imaging part, 827: Earphone part, 832: Lens, 1000: Insulating layer, 6500: Electronic equipment, 6501: Enclosure, 6502: Display unit, 6503: Power button, 6504: Button, 6505: Speaker, 6506: Microphone, 6507: Camera, 6508: Light source, 6510: Protective component, 6511: Display panel, 6512: Optical component, 6513: Touch sensor panel, 6515: FPC, 6516: IC, 6517: Printed circuit board, 6518: Battery, 7000: Display unit, 7100: Television equipment, 7151: Remote control unit, 7171: Enclosure, 7173: Stand, 7200: Notebook personal computer, 7211: Case Body, 7212: Keyboard, 7213: Pointing device, 7214: External connection port, 7300: Digital signage, 7301: Enclosure, 7303: Speaker, 7311: Information terminal, 7400: Digital signage, 7401: Pillar, 7411: Information terminal, 9000: Enclosure, 9001: Display unit, 9002: Camera, 9003: Speaker, 9005: Operation keys, 9006: Connection terminal, 9007: Sensor, 9008: Microphone, 9050: Icon, 9051: Information, 9052: Information, 9053: Information, 9054: Information, 9055: Hinge9171: Mobile information terminal, 9172: Mobile information terminal, 9173: Tablet terminal, 9200: Mobile information terminal, 9201: Mobile information terminal,

Claims

A compound represented by the general formula (G1). (In the above general formula (G1), X １ ~X ８ Each of the following independently represents one of the following: an alkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 7 to 10 carbon atoms and a cross-linked structure, and a substituted or unsubstituted silyl group having 3 to 20 carbon atoms. However, X １ ~X ８ At least one of the following represents either a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, or a substituted or unsubstituted cycloalkyl group having 7 to 10 carbon atoms and a cross-linked structure. Note that some or all of the hydrogen atoms in the compound represented by general formula (G1) may be deuterium. In claim 1, The aforementioned X １ ~X ８ A compound in which four or more of the members are either substituted or unsubstituted cycloalkyl groups having 3 to 10 carbon atoms, or substituted or unsubstituted cycloalkyl groups having a crosslinked structure having 7 to 10 carbon atoms. In claim 1, The aforementioned X １ ~X ８ A compound in which four of the elements are either a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, or a substituted or unsubstituted cycloalkyl group having a cross-linked structure having 7 to 10 carbon atoms, and the remaining four elements are an alkyl group having 3 to 10 carbon atoms. In claim 3, A compound in which the alkyl group having 3 to 10 carbon atoms is a tert-butyl group. A compound represented by the general formula (G2). (In the above general formula (G2), X １ , X ２ , X ７ and X ８ each independently represents any one of a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms and a substituted or unsubstituted cycloalkyl group having a crosslinked structure with 7 to 10 carbon atoms. Note that some or all of the hydrogen atoms of the compound represented by the general formula (G2) may be deuterium.) In any one of claims 2 to 5, A compound in which the substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, and the substituted or unsubstituted cycloalkyl group having a cross-linked structure having 7 to 10 carbon atoms, are cyclohexyl groups. In any one of claims 2 to 5, A compound in which the substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms and the substituted or unsubstituted cycloalkyl group having a cross-linked structure having 7 to 10 carbon atoms are adamantyl groups. A compound represented by the general formula (G3). (In the above general formula (G3), X ３ ~X ６ Each of these independently represents one of the following: a C3 to C10 alkyl group, a substituted or unsubstituted C3 to C10 cycloalkyl group, a substituted or unsubstituted C7 to C10 cycloalkyl group having a cross-linked structure, or a substituted or unsubstituted C3 to C20 silyl group. Note that some or all of the hydrogen atoms in the compound represented by general formula (G3) may be deuterium. A compound represented by the general formula (G4). (In the above general formula (G4), X ３ ~X ６ Each of these independently represents one of the following: an alkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 7 to 10 carbon atoms and a cross-linked structure, or a substituted or unsubstituted silyl group having 3 to 20 carbon atoms. Note that some or all of the hydrogen atoms in the compound represented by general formula (G4) may be deuterium. In claim 8 or claim 9, X ３ ~X ６ Each of these compounds independently comprises either a C3 to C10 alkyl group or a substituted or unsubstituted C3 to C20 silyl group. In claim 10, X ３ ~X ６ However, the compound is a branched alkyl group having 3 to 10 carbon atoms, either substituted or unsubstituted. In claim 10, X ３ ~X ６ However, it is a compound with a tert-butyl group. The compound represented by the following structural formula. The compound represented by the following structural formula.

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