Iridium complex, light-emitting element, display device, electronic device, and lighting device

Abstract

One of the purposes of one embodiment of the present invention is to provide a light-emitting element with high luminous efficiency. The light-emitting element includes a first organic compound, a second organic compound and a guest material. The LUMO energy level of the first organic compound is lower than the LUMO energy level of the second organic compound, and the HOMO energy level of the first organic compound is lower than the HOMO energy level of the second organic compound. The LUMO energy level of the guest material is higher than the LUMO energy level of the first organic compound, and the HOMO energy level of the guest material is lower than the HOMO energy level of the second organic compound. The guest material has the function of converting triplet excitation energy into luminescence. The first organic compound and the second organic compound form an exciplex.

Description

Technical Field

[0001] One embodiment of the present invention relates to a light-emitting element or a display device, an electronic device, and a lighting device including the light-emitting element.

[0002] Note that one embodiment of the present invention is not limited to the above-mentioned technical field. The technical field of one embodiment of the invention disclosed in this specification, etc., relates to an object, method, or manufacturing method. In addition, one embodiment of the present invention relates to a process, machine, product, or composition of matter. More specifically, as examples of the technical field of one embodiment of the present invention disclosed in this specification, semiconductor devices, display devices, liquid crystal display devices, light-emitting devices, lighting devices, power storage devices, storage devices, and driving methods or manufacturing methods of these devices can be cited. Background Art

[0003] In recent years, research and development of light-emitting elements using electroluminescence (EL) has become increasingly popular. The basic structure of these light-emitting elements is a structure in which a layer containing a light-emitting substance (EL layer) is sandwiched between a pair of electrodes. By applying voltage between a pair of electrodes of the element, light from the light-emitting substance can be obtained.

[0004] Since the light-emitting element is a self-luminous light-emitting element, a display device using the light-emitting element has the following advantages: good visibility; no backlight source is required; low power consumption, etc. In addition, the display device also has the following advantages: it can be made thin and light; and has a fast response speed, etc.

[0005] In a light-emitting element (e.g., an organic EL element) that uses an organic compound as a light-emitting substance and provides an EL layer containing the light-emitting substance between a pair of electrodes, a voltage is applied between the pair of electrodes, and electrons and holes are injected from the cathode and the anode into the light-emitting EL layer, respectively, so that current flows. Then, the injected electrons and holes recombine to make the light-emitting organic compound into an excited state, so that light emission can be obtained.

[0006] As the types of excited states formed by organic compounds, there are singlet excited states (S * ) and triplet excited state (T * ), the emission from the singlet excited state is called fluorescence, and the emission from the triplet excited state is called phosphorescence. In addition, in this light-emitting element, the statistical generation ratio of the singlet excited state to the triplet excited state is S * :T *=1:3. In other words, the luminous efficiency of a luminescent element using a compound that emits phosphorescence (phosphorescent compound) is higher than that of a luminescent element using a compound that emits fluorescence (fluorescent compound). Therefore, in recent years, luminescent elements using phosphorescent compounds that can convert triplet excited states into luminescent light have been actively developed (for example, refer to Patent Document 1).

[0007] The energy required for the excitation of an organic compound depends on the energy difference between the LUMO energy level and the HOMO energy level of the organic compound, and the energy difference is roughly equivalent to the energy of the singlet excited state. In a light-emitting element using a phosphorescent compound, the triplet excitation energy can be converted into the energy of luminescence. Thus, when the energy difference between the singlet excited state and the triplet excited state formed in the organic compound is large, in order to make the energy required for the excitation of the organic compound higher than the energy of luminescence, the difference therebetween is equivalent to the energy difference. In order to make the energy difference between the energy required for the excitation of the organic compound and the energy of luminescence affect the characteristics of the light-emitting element, the driving voltage of the light-emitting element is increased. Therefore, a method of reducing the driving voltage is being studied (see patent document 2).

[0008] In addition, in light-emitting elements using phosphorescent compounds, especially in light-emitting elements that emit blue light, it is difficult to develop stable compounds having a high triplet excitation energy level, so they have not yet been put into practical use. Therefore, there is a need for the development of phosphorescent compounds having high luminous efficiency and stability, and phosphorescent light-emitting elements having high luminous efficiency and excellent reliability.

[0009] [References]

[0010] [Patent Document]

[0011] [Patent Document 1] Japanese Patent Application Publication No. 2010-182699

[0012] [Patent Document 2] Japanese Patent Application Publication No. 2012-212879 Summary of the invention

[0013] As phosphorescent compounds with high luminous efficiency, iridium complexes are known. In addition, as iridium complexes with high luminous energy, iridium complexes with nitrogen-containing five-membered heterocyclic skeleton as its part are known. Although this nitrogen-containing five-membered heterocyclic skeleton has high triple excitation energy, the characteristic of receiving electrons is low compared with nitrogen-containing six-membered heterocyclic skeleton. Thus, the LUMO energy level of the iridium complexes with nitrogen-containing five-membered heterocyclic skeleton as its part is higher, and electronic carriers are not easily injected. Therefore, the iridium complexes with nitrogen-containing five-membered heterocyclic skeleton as its part are difficult to excite because of the direct recombination of carriers, so efficient luminescence is very difficult.

[0014] Thus, one of the purposes of one embodiment of the present invention is to provide a light-emitting element comprising a phosphorescent compound and having high luminous efficiency. Furthermore, one of the purposes of one embodiment of the present invention is to provide a light-emitting element having reduced power consumption. Furthermore, one of the purposes of one embodiment of the present invention is to provide a light-emitting element having high reliability. Furthermore, one of the purposes of one embodiment of the present invention is to provide a novel compound. Furthermore, one of the purposes of one embodiment of the present invention is to provide a light-emitting element comprising a novel compound. Furthermore, one of the purposes of one embodiment of the present invention is to provide a novel light-emitting element. Furthermore, one of the purposes of one embodiment of the present invention is to provide a novel light-emitting device. Furthermore, one of the purposes of one embodiment of the present invention is to provide a novel display device.

[0015] Note that the description of the above-mentioned purpose does not prevent the existence of other purposes. One mode of the present invention does not necessarily need to achieve all of the above-mentioned purposes. In addition, purposes other than the above-mentioned purpose can be known and extracted from the description of the specification, etc.

[0016] One embodiment of the present invention is a light-emitting element including an exciplex capable of efficiently exciting a phosphorescent compound. Another embodiment of the present invention is a light-emitting element including a novel phosphorescent compound capable of emitting light with high luminescent energy.

[0017] Thus, one embodiment of the present invention is a light-emitting element, comprising: a first organic compound; a second organic compound; and a guest material, wherein the LUMO energy level of the first organic compound is lower than the LUMO energy level of the second organic compound, the HOMO energy level of the first organic compound is lower than the HOMO energy level of the second organic compound, the energy difference between the LUMO energy level and the HOMO energy level of the guest material is greater than the energy difference between the LUMO energy level of the first organic compound and the HOMO energy level of the second organic compound, the guest material has a function of converting triplet excitation energy into luminescence, and the first organic compound and the second organic compound are a combination that forms an excimer complex.

[0018] Another embodiment of the present invention is a light-emitting element, comprising: a first organic compound; a second organic compound; and a guest material, wherein the LUMO energy level of the first organic compound is lower than the LUMO energy level of the second organic compound, the HOMO energy level of the first organic compound is lower than the HOMO energy level of the second organic compound, the LUMO energy level of the guest material is higher than the LUMO energy level of the first organic compound, the HOMO energy level of the guest material is lower than the HOMO energy level of the second organic compound, the guest material has a function of converting triplet excitation energy into luminescence, and the first organic compound and the second organic compound are a combination that forms an excimer complex.

[0019] Another embodiment of the present invention is a light-emitting element, comprising: a first organic compound; a second organic compound; and a guest material, wherein the LUMO energy level of the first organic compound is lower than the LUMO energy level of the second organic compound, the HOMO energy level of the first organic compound is lower than the HOMO energy level of the second organic compound, the LUMO energy level of the guest material is equal to the LUMO energy level of the first organic compound, the HOMO energy level of the guest material is lower than the HOMO energy level of the second organic compound, the guest material has a function of converting triplet excitation energy into luminescence, and the first organic compound and the second organic compound are a combination that forms an excimer complex.

[0020] Another embodiment of the present invention is a light-emitting element, comprising: a first organic compound; a second organic compound; and a guest material, wherein the LUMO energy level of the first organic compound is lower than the LUMO energy level of the second organic compound, the HOMO energy level of the first organic compound is lower than the HOMO energy level of the second organic compound, the LUMO energy level of the guest material is higher than the LUMO energy level of the first organic compound, the HOMO energy level of the guest material is equal to the HOMO energy level of the second organic compound, the guest material has a function of converting triplet excitation energy into luminescence, and the first organic compound and the second organic compound are a combination that forms an excimer complex.

[0021] Another embodiment of the present invention is a light-emitting element, comprising: a first organic compound; a second organic compound; and a guest material, wherein the reduction potential of the first organic compound is higher than the reduction potential of the second organic compound, the oxidation potential of the first organic compound is higher than the oxidation potential of the second organic compound, the reduction potential of the guest material is lower than the reduction potential of the first organic compound, the oxidation potential of the guest material is higher than the oxidation potential of the second organic compound, the guest material has a function of converting triplet excitation energy into luminescence, and the first organic compound and the second organic compound are a combination that forms an excimer complex.

[0022] Another embodiment of the present invention is a light-emitting element, comprising: a first organic compound; a second organic compound; and a guest material, wherein the reduction potential of the first organic compound is higher than the reduction potential of the second organic compound, the oxidation potential of the first organic compound is higher than the oxidation potential of the second organic compound, the reduction potential of the guest material is equal to the reduction potential of the first organic compound, the oxidation potential of the guest material is higher than the oxidation potential of the second organic compound, the guest material has a function of converting triplet excitation energy into luminescence, and the first organic compound and the second organic compound are a combination that forms an excimer complex.

[0023] Another embodiment of the present invention is a light-emitting element, comprising: a first organic compound; a second organic compound; and a guest material, wherein the reduction potential of the first organic compound is higher than the reduction potential of the second organic compound, the oxidation potential of the first organic compound is higher than the oxidation potential of the second organic compound, the reduction potential of the guest material is lower than the reduction potential of the first organic compound, the oxidation potential of the guest material is equal to the oxidation potential of the second organic compound, the guest material has a function of converting triplet excitation energy into luminescence, and the first organic compound and the second organic compound are a combination that forms an excimer complex.

[0024] In each of the above structures, the energy difference between the LUMO level of the first organic compound and the HOMO level of the second organic compound is preferably equal to or greater than the transition energy calculated from the absorption edge of the guest material.

[0025] In each of the above structures, the energy difference between the LUMO level of the first organic compound and the HOMO level of the second organic compound is preferably equal to or greater than the energy of light emission exhibited by the guest material.

[0026] In each of the above structures, the energy difference between the LUMO level and the HOMO level of the guest material is preferably greater than the transition energy calculated from the absorption edge of the guest material by 0.4 eV or more.

[0027] In each of the above structures, the energy difference between the LUMO level and the HOMO level of the guest material is preferably greater than the energy of luminescence exhibited by the guest material by 0.4 eV or more.

[0028] In each of the above structures, the emission spectrum of light emitted by the guest material preferably has at least one peak in a wavelength region of 400 nm to less than 505 nm.

[0029] In each of the above structures, the exciplex preferably has a function of supplying excitation energy to the guest material. In addition, the emission spectrum exhibited by the exciplex preferably has a region overlapping with the absorption band on the lowest energy side of the guest material.

[0030] In each of the above structures, the guest material preferably includes iridium. In addition, the guest material preferably includes a ligand coordinated to iridium, and the ligand preferably has a nitrogen-containing five-membered heterocyclic skeleton. In addition, the ligand preferably has a triazole skeleton or an imidazole skeleton.

[0031] Another embodiment of the present invention is an iridium complex represented by the general formula (G1).

[0032]

[0033] In the general formula (G1), Ar 1represents a substituted or unsubstituted first aryl group having 6 to 13 carbon atoms. 2 represents a substituted or unsubstituted second aryl group having 6 to 13 carbon atoms. 1 and Q 2 Each independently represents N or CR, and R represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a halogenated alkyl group having 1 to 6 carbon atoms, and a substituted or unsubstituted third aryl group having 6 to 13 carbon atoms. 1 and Q 2 At least one of the first to third aryl groups has a cyano group.

[0034] Another embodiment of the present invention is an iridium complex represented by the general formula (G2).

[0035]

[0036] In the general formula (G2), Ar 1 represents a substituted or unsubstituted first aryl group having 6 to 13 carbon atoms. 1 To R 4 Each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, a substituted or unsubstituted fourth aryl group having 6 to 13 carbon atoms, and a cyano group. 1 and Q 2 Each independently represents N or CR, and R represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a halogenated alkyl group having 1 to 6 carbon atoms, and a substituted or unsubstituted third aryl group having 6 to 13 carbon atoms. 1 and Q 2 At least one of the first aryl group, the third aryl group, the fourth aryl group and R 1 To R 4 At least one of them has a cyano group.

[0037] Another embodiment of the present invention is an iridium complex represented by the general formula (G3).

[0038]

[0039] In the general formula (G3), Ar 1 represents a substituted or unsubstituted first aryl group having 6 to 13 carbon atoms. 1 To R 4 R each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, a substituted or unsubstituted fourth aryl group having 6 to 13 carbon atoms, and a cyano group. 5represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a halogenated alkyl group having 1 to 6 carbon atoms, and a substituted or unsubstituted third aryl group having 6 to 13 carbon atoms. The first aryl group, the third aryl group, the fourth aryl group, and R 1 To R 4 At least one of them has a cyano group.

[0040] Another embodiment of the present invention is an iridium complex represented by the general formula (G4).

[0041]

[0042] In the general formula (G4), Ar 1 represents a substituted or unsubstituted first aryl group having 6 to 13 carbon atoms. 1 To R 4 R each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and a substituted or unsubstituted fourth aryl group having 6 to 13 carbon atoms. 5 and R 6 Each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a halogenated alkyl group having 1 to 6 carbon atoms, and a substituted or unsubstituted third aryl group having 6 to 13 carbon atoms. The first aryl group, the third aryl group, the fourth aryl group, and R 1 To R 4 At least one of them has a cyano group.

[0043] In addition, in the above structures, Ar 1 A substituted or unsubstituted phenyl group is preferred, and the phenyl group preferably has a cyano group as a substituent.

[0044] Another embodiment of the present invention is an iridium complex represented by the general formula (G5).

[0045]

[0046] In the general formula (G5), R 1 To R 4 R each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. 5 R represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a halogenated alkyl group having 1 to 6 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. 7 and R 11 represents an alkyl group having 1 to 6 carbon atoms, R 7 and R 11 have the same structure as each other. 8 To R 10R each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, a substituted or unsubstituted phenyl group and a cyano group. 8 To R 10 At least one of them has a cyano group.

[0047] Another embodiment of the present invention is an iridium complex represented by the general formula (G6).

[0048]

[0049] In the general formula (G6), R 1 To R 4 R each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. 5 and R 6 R each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a haloalkyl group having 1 to 6 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. 7 and R 11 represents an alkyl group having 1 to 6 carbon atoms, R 7 and R 11 have the same structure as each other, R 8 To R 10 R each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, a substituted or unsubstituted phenyl group and a cyano group. 8 To R 10 At least one of them has a cyano group.

[0050] Another embodiment of the present invention is an iridium complex represented by the general formula (G7).

[0051]

[0052] In the general formula (G7), Ar 1 represents a substituted or unsubstituted first aryl group having 6 to 13 carbon atoms. 1 To R 4 R each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and a substituted or unsubstituted fourth aryl group having 6 to 13 carbon atoms. 6 represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a halogenated alkyl group having 1 to 6 carbon atoms, and a substituted or unsubstituted third aryl group having 6 to 13 carbon atoms. The first aryl group, the third aryl group, the fourth aryl group, and R 1 To R 4 At least one of them has a cyano group.

[0053] In addition, in the above structure, Ar 1 A substituted or unsubstituted phenyl group is preferred, and the phenyl group preferably has a cyano group.

[0054] Another embodiment of the present invention is an iridium complex represented by the general formula (G8).

[0055]

[0056] In the general formula (G8), R 1 To R 4 R each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. 6 R represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a halogenated alkyl group having 1 to 6 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. 7 and R 11 represents an alkyl group having 1 to 6 carbon atoms, R 7 and R 11 have the same structure as each other. 8 To R 10 R each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, a substituted or unsubstituted phenyl group and a cyano group. 8 To R 10 At least one of them has a cyano group.

[0057] Another embodiment of the present invention is a light-emitting element including any one of the above-mentioned iridium complexes.

[0058] Another embodiment of the present invention is a light-emitting element, comprising: any one of the above-mentioned iridium complexes; a first organic compound; and a second organic compound, wherein the LUMO energy level of the first organic compound is lower than the LUMO energy level of the second organic compound, the HOMO energy level of the first organic compound is lower than the HOMO energy level of the second organic compound, the energy difference between the LUMO energy level and the HOMO energy level of the iridium complex is greater than the energy difference between the LUMO energy level of the first organic compound and the HOMO energy level of the second organic compound, and the first organic compound and the second organic compound are a combination that forms an excited complex.

[0059] Another embodiment of the present invention is a light-emitting element, comprising: any one of the above-mentioned iridium complexes; a first organic compound; and a second organic compound, wherein the LUMO energy level of the first organic compound is lower than the LUMO energy level of the second organic compound, the HOMO energy level of the first organic compound is lower than the HOMO energy level of the second organic compound, the LUMO energy level of the iridium complex is higher than the LUMO energy level of the first organic compound, the HOMO energy level of the iridium complex is lower than the HOMO energy level of the second organic compound, and the first organic compound and the second organic compound are a combination that forms an excited complex.

[0060] Another embodiment of the present invention is a light-emitting element, comprising: any one of the above-mentioned iridium complexes; a first organic compound; and a second organic compound, wherein the LUMO energy level of the first organic compound is lower than the LUMO energy level of the second organic compound, the HOMO energy level of the first organic compound is lower than the HOMO energy level of the second organic compound, the LUMO energy level of the iridium complex is equal to the LUMO energy level of the first organic compound, the HOMO energy level of the iridium complex is lower than the HOMO energy level of the second organic compound, and the first organic compound and the second organic compound are a combination that forms an excited complex.

[0061] Another embodiment of the present invention is a light-emitting element, comprising: any one of the above-mentioned iridium complexes; a first organic compound; and a second organic compound, wherein the LUMO energy level of the first organic compound is lower than the LUMO energy level of the second organic compound, the HOMO energy level of the first organic compound is lower than the HOMO energy level of the second organic compound, the LUMO energy level of the iridium complex is higher than the LUMO energy level of the first organic compound, the HOMO energy level of the iridium complex is equal to the HOMO energy level of the second organic compound, and the first organic compound and the second organic compound are a combination that forms an excited complex.

[0062] Another embodiment of the present invention is a light-emitting element, comprising: any one of the above-mentioned iridium complexes; a first organic compound; and a second organic compound, wherein the reduction potential of the first organic compound is higher than the reduction potential of the second organic compound, the oxidation potential of the first organic compound is higher than the oxidation potential of the second organic compound, the reduction potential of the iridium complex is lower than the reduction potential of the first organic compound, the oxidation potential of the iridium complex is higher than the oxidation potential of the second organic compound, and the first organic compound and the second organic compound are a combination that forms an excited complex.

[0063] Another embodiment of the present invention is a light-emitting element, comprising: any one of the above-mentioned iridium complexes; a first organic compound; and a second organic compound, wherein the reduction potential of the first organic compound is higher than the reduction potential of the second organic compound, the oxidation potential of the first organic compound is higher than the oxidation potential of the second organic compound, the reduction potential of the iridium complex is equal to the reduction potential of the first organic compound, the oxidation potential of the iridium complex is higher than the oxidation potential of the second organic compound, and the first organic compound and the second organic compound are a combination that forms an excited complex.

[0064] Another embodiment of the present invention is a light-emitting element, comprising: any one of the above-mentioned iridium complexes; a first organic compound; and a second organic compound, wherein the reduction potential of the first organic compound is higher than the reduction potential of the second organic compound, the oxidation potential of the first organic compound is higher than the oxidation potential of the second organic compound, the reduction potential of the iridium complex is lower than the reduction potential of the first organic compound, the oxidation potential of the iridium complex is equal to the oxidation potential of the second organic compound, and the first organic compound and the second organic compound are a combination that forms an excited complex.

[0065] In each of the above structures, the exciplex preferably has a function of supplying excitation energy to the iridium complex. In addition, the light emission exhibited by the exciplex preferably has a region overlapping with the absorption band on the lowest energy side of the iridium complex.

[0066] In the above structure, the energy difference between the LUMO level of the first organic compound and the HOMO level of the second organic compound is preferably equal to or greater than the transition energy calculated from the absorption edge of the iridium complex.

[0067] In the above structure, the energy difference between the LUMO level of the first organic compound and the HOMO level of the second organic compound is preferably equal to or greater than the energy of light emission exhibited by the iridium complex.

[0068] In addition, in each of the above structures, the first organic compound preferably has a function of being able to transport electrons, and the second organic compound preferably has a function of being able to transport holes. In addition, the first organic compound preferably has a π-electron-deficient aromatic heterocyclic skeleton, and the second organic compound preferably has at least one of a π-electron-rich aromatic heterocyclic skeleton and an aromatic amine skeleton.

[0069] Another embodiment of the present invention is a display device, comprising: a light-emitting element of any one of the above-mentioned structures; and at least one of a color filter and a transistor. Another embodiment of the present invention is an electronic device, comprising: the display device; and at least one of a frame and a touch sensor. Another embodiment of the present invention is a lighting device, comprising: a light-emitting element of any one of the above-mentioned structures; and at least one of a frame and a touch sensor. In addition, one embodiment of the present invention includes not only a light-emitting device having a light-emitting element in its scope, but also an electronic device having a light-emitting device. Therefore, the light-emitting device in this specification refers to an image display device or a light source (for example, a lighting device). In addition, the light-emitting device is sometimes also included in the following modules: a display module in which a connector such as an FPC (Flexible Printed Circuit) or a TCP (Tape Carrier Package) is connected to the light-emitting device; a display module in which a printed circuit board is provided on the end of the TCP; or a display module in which an IC (integrated circuit) is directly mounted on the light-emitting element by a COG (Chip On Glass) method.

[0070] According to one embodiment of the present invention, a light-emitting element containing a phosphorescent compound and having high luminous efficiency can be provided. In addition, according to one embodiment of the present invention, a light-emitting element with reduced power consumption can be provided. In addition, according to one embodiment of the present invention, a light-emitting element with high reliability can be provided. In addition, according to one embodiment of the present invention, a novel compound can be provided. In addition, according to one embodiment of the present invention, a novel light-emitting element containing a novel compound can be provided. In addition, according to one embodiment of the present invention, a novel light-emitting element can be provided. In addition, according to one embodiment of the present invention, a novel light-emitting device can be provided. In addition, according to one embodiment of the present invention, a novel display device can be provided.

[0071] Note that the description of these effects does not prevent the existence of other effects. One mode of the present invention does not necessarily need to achieve all of the above effects. In addition, the description of the specification, drawings, and claims clearly indicates that there are effects other than the above effects, and effects other than the above effects can be obtained from the description of the specification, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] Figure 1A and Figure 1B is a schematic cross-sectional view of a light-emitting element according to one embodiment of the present invention;

[0073] Figure 2A and Figure 2Bis a diagram illustrating the correlation between energy bands and energy levels in a light-emitting layer of a light-emitting element according to one embodiment of the present invention;

[0074] Figure 3A and Figure 3B is a schematic cross-sectional view of a light-emitting element according to one embodiment of the present invention;

[0075] Figure 4 is a schematic cross-sectional view of a light-emitting element according to one embodiment of the present invention;

[0076] Figure 5A and Figure 5B Each of them is a schematic cross-sectional view of a light-emitting element according to one embodiment of the present invention;

[0077] Fig. 6A and Figure 6B Each of them is a schematic cross-sectional view of a light-emitting element according to one embodiment of the present invention;

[0078] 7A to 7C is a schematic cross-sectional view illustrating a method for manufacturing a light-emitting element according to one embodiment of the present invention;

[0079] FIG. 8A to FIG. 8C is a schematic cross-sectional view illustrating a method for manufacturing a light-emitting element according to one embodiment of the present invention;

[0080] Fig.9A and Fig. 9B 1 is a top view and a schematic cross-sectional view illustrating a display device according to one embodiment of the present invention;

[0081] Fig. 10A and Fig. 10B is a schematic cross-sectional view of a display device for explaining one embodiment of the present invention;

[0082] Fig.11 is a schematic cross-sectional view of a display device for explaining one embodiment of the present invention;

[0083] Fig. 12A and Fig. 12B is a schematic cross-sectional view of a display device for explaining one embodiment of the present invention;

[0084] Fig.13A and Fig. 13B is a schematic cross-sectional view of a display device for explaining one embodiment of the present invention;

[0085] Fig.14 is a schematic cross-sectional view of a display device for explaining one embodiment of the present invention;

[0086] Fig.15A and Fig. 15B is a schematic cross-sectional view of a display device for explaining one embodiment of the present invention;

[0087] Fig.16 is a schematic cross-sectional view of a display device for explaining one embodiment of the present invention;

[0088] Fig.17A and Fig. 17B is a schematic cross-sectional view of a display device for explaining one embodiment of the present invention;

[0089] Fig.18A and Fig.18B is a block diagram and a circuit diagram illustrating a display device according to one embodiment of the present invention;

[0090] Fig.19A and Fig.19B is a circuit diagram illustrating a pixel circuit of a display device according to one embodiment of the present invention;

[0091] Fig. 20A and Fig. 20B is a circuit diagram illustrating a pixel circuit of a display device according to one embodiment of the present invention;

[0092] Fig.21A and Fig. 21B is a perspective view showing an example of a touch panel according to one embodiment of the present invention;

[0093] FIG. 22A to FIG. 22C is a cross-sectional view showing an example of a display device and a touch sensor according to one embodiment of the present invention;

[0094] Fig.23A and Fig. 23B is a cross-sectional view showing an example of a touch panel according to one embodiment of the present invention;

[0095] Fig.24A and Fig. 24B is a block diagram and timing diagram of a touch sensor according to one embodiment of the present invention;

[0096] Fig.25 is a circuit diagram of a touch sensor according to one embodiment of the present invention;

[0097] Fig.26 is a perspective view of a display module for explaining one embodiment of the present invention;

[0098] FIG. 27A to FIG. 27G is a diagram illustrating an electronic device according to one embodiment of the present invention;

[0099] FIG. 28A to FIG. 28D is a diagram illustrating an electronic device according to one embodiment of the present invention;

[0100] Fig.29A and Fig.29B is a perspective view of a display device for explaining one embodiment of the present invention;

[0101] FIG. 30A to FIG. 30C is a perspective view and a cross-sectional view illustrating a light emitting device according to one embodiment of the present invention;

[0102] FIG. 31A to FIG. 31D is a cross-sectional view illustrating a light emitting device according to one embodiment of the present invention;

[0103] Fig.32A and Fig.32B is a diagram illustrating an electronic device according to one embodiment of the present invention, Fig.32C is a diagram illustrating a lighting device according to one embodiment of the present invention;

[0104] Fig.33 is a diagram illustrating a lighting device according to one embodiment of the present invention;

[0105] Fig.34 is an NMR spectrum of the compound of one embodiment of the present invention;

[0106] Fig.35 is a diagram illustrating an absorption spectrum and an emission spectrum of a compound according to one embodiment of the present invention;

[0107] Fig.36 is a diagram illustrating a liquid chromatogram of a compound according to one embodiment of the present invention;

[0108] Fig.37 is an NMR spectrum of the compound of one embodiment of the present invention;

[0109] Fig.38 is a diagram illustrating an absorption spectrum and an emission spectrum of a compound according to one embodiment of the present invention;

[0110] Fig.39 is an NMR spectrum of the compound of one embodiment of the present invention;

[0111] Fig.40 is a diagram illustrating an absorption spectrum and an emission spectrum of a compound according to one embodiment of the present invention;

[0112] Fig.41 is a diagram illustrating a liquid chromatogram of a compound according to one embodiment of the present invention;

[0113] Fig.42 is a schematic cross-sectional view illustrating a light emitting element in an embodiment;

[0114] Fig.43A and Fig.43B is a graph illustrating an electric field emission spectrum of a host material in an example;

[0115] Fig.44 is a graph illustrating current efficiency-luminance characteristics of a light-emitting element in an example;

[0116] Fig.45is a diagram illustrating the brightness-voltage characteristics of a light-emitting element in an example;

[0117] Fig.46 is a graph illustrating external quantum efficiency-luminance characteristics of a light-emitting element in an example;

[0118] Fig.47 is a diagram illustrating power efficiency-luminance characteristics of a light-emitting element in an example;

[0119] Fig.48A and Fig.48B is a diagram illustrating an electric field emission spectrum of a light-emitting element in an example;

[0120] Fig.49 is a graph illustrating absorption spectra of compounds in Examples;

[0121] Fig.50 is a diagram illustrating the reliability test results of the light emitting element in the embodiment;

[0122] Fig.51 is a graph illustrating current efficiency-luminance characteristics of a light-emitting element in an example;

[0123] Fig.52 is a diagram illustrating the brightness-voltage characteristics of a light-emitting element in an example;

[0124] Fig.53 is a graph illustrating external quantum efficiency-luminance characteristics of a light-emitting element in an example;

[0125] Fig.54 is a diagram illustrating power efficiency-luminance characteristics of a light-emitting element in an example;

[0126] Fig.55 is a diagram illustrating an electric field emission spectrum of a light-emitting element in an example;

[0127] Fig.56 is a graph illustrating current efficiency-luminance characteristics of a light-emitting element in an example;

[0128] Fig.57 is a diagram illustrating the brightness-voltage characteristics of a light-emitting element in an example;

[0129] Fig.58 is a graph illustrating current density-voltage characteristics of a light-emitting element in an example;

[0130] Fig.59 is a graph illustrating external quantum efficiency-luminance characteristics of a light-emitting element in an example;

[0131] Fig.60 is a diagram illustrating power efficiency-luminance characteristics of a light-emitting element in an example;

[0132] Fig.61 is a diagram illustrating an electric field emission spectrum of a light-emitting element in an example;

[0133] Fig.62 is a diagram illustrating the reliability test results of the light emitting element in the embodiment;

[0134] Fig.63 is an NMR spectrum of the compound of one embodiment of the present invention;

[0135] Fig.64 is a diagram illustrating an absorption spectrum and an emission spectrum of a compound according to one embodiment of the present invention;

[0136] Fig.65 is a diagram illustrating a liquid chromatogram of a compound according to one embodiment of the present invention;

[0137] Fig.66 is an NMR spectrum of the compound of one embodiment of the present invention;

[0138] Fig.67 is a diagram illustrating an absorption spectrum and an emission spectrum of a compound according to one embodiment of the present invention;

[0139] Fig.68 is a diagram illustrating a liquid chromatogram of a compound according to one embodiment of the present invention;

[0140] Fig.69 is an NMR spectrum of the compound of one embodiment of the present invention;

[0141] Fig.70 is a diagram illustrating an absorption spectrum and an emission spectrum of a compound according to one embodiment of the present invention;

[0142] Fig.71 is a diagram illustrating a liquid chromatogram of a compound according to one embodiment of the present invention;

[0143] Fig.72 is an NMR spectrum of the compound of one embodiment of the present invention;

[0144] Fig.73 is a diagram illustrating an absorption spectrum and an emission spectrum of a compound according to one embodiment of the present invention;

[0145] Fig.74 is a diagram illustrating a liquid chromatogram of a compound according to one embodiment of the present invention;

[0146] Fig.75 is an NMR spectrum of the compound of one embodiment of the present invention;

[0147] Fig.76 is a diagram illustrating an absorption spectrum and an emission spectrum of a compound according to one embodiment of the present invention;

[0148] Fig.77 is a diagram illustrating a liquid chromatogram of a compound according to one embodiment of the present invention;

[0149] Fig.78 is an NMR spectrum of the compound of one embodiment of the present invention;

[0150] Fig.79 is a diagram illustrating an absorption spectrum and an emission spectrum of a compound according to one embodiment of the present invention;

[0151] Fig.80 is a diagram illustrating a liquid chromatogram of a compound according to one embodiment of the present invention;

[0152] Fig.81 is an NMR spectrum of the compound of one embodiment of the present invention;

[0153] Fig.82 is a diagram illustrating an absorption spectrum and an emission spectrum of a compound according to one embodiment of the present invention;

[0154] Fig.83 is an NMR spectrum of the compound of one embodiment of the present invention;

[0155] Fig.84 is a diagram illustrating an absorption spectrum and an emission spectrum of a compound according to one embodiment of the present invention;

[0156] Fig.85 is a graph illustrating current efficiency-luminance characteristics of a light-emitting element in an example;

[0157] Fig.86 is a diagram illustrating the brightness-voltage characteristics of a light-emitting element in an example;

[0158] Fig.87 is a graph illustrating external quantum efficiency-luminance characteristics of a light-emitting element in an example;

[0159] Fig.88 is a diagram illustrating power efficiency-luminance characteristics of a light-emitting element in an example;

[0160] Fig.89 is a diagram illustrating an electric field emission spectrum of a light-emitting element in an example;

[0161] Fig.90 is a graph illustrating the emission spectrum of the host material in the Examples;

[0162] Fig.91 is a graph illustrating current efficiency-luminance characteristics of a light-emitting element in an example;

[0163] Fig.92 is a diagram illustrating the brightness-voltage characteristics of a light-emitting element in an example;

[0164] Fig.93 is a graph illustrating external quantum efficiency-luminance characteristics of a light-emitting element in an example;

[0165] Fig.94 is a diagram illustrating power efficiency-luminance characteristics of a light-emitting element in an example;

[0166] Fig.95 is a diagram illustrating an electric field emission spectrum of a light-emitting element in an example;

[0167] Fig.96 is a graph illustrating current efficiency-luminance characteristics of a light-emitting element in an example;

[0168] Fig.97 is a diagram illustrating the brightness-voltage characteristics of a light-emitting element in an example;

[0169] Fig.98 is a graph illustrating external quantum efficiency-luminance characteristics of a light-emitting element in an example;

[0170] Fig.99 is a diagram illustrating power efficiency-luminance characteristics of a light-emitting element in an example;

[0171] Fig.100 is a diagram illustrating an electric field emission spectrum of a light-emitting element in an example;

[0172] Fig.101 is a graph illustrating current efficiency-luminance characteristics of a light-emitting element in an example;

[0173] Fig.102 is a diagram illustrating the brightness-voltage characteristics of a light-emitting element in an example;

[0174] Fig.103 is a graph illustrating external quantum efficiency-luminance characteristics of a light-emitting element in an example;

[0175] Fig.104 is a diagram illustrating power efficiency-luminance characteristics of a light-emitting element in an example;

[0176] Fig.105 is a diagram illustrating an electric field emission spectrum of a light-emitting element in an example;

[0177] Fig.106 is a graph illustrating the emission spectrum of the host material in the Examples;

[0178] Fig.107 is a graph illustrating current efficiency-luminance characteristics of a light-emitting element in an example;

[0179] Fig.108 is a diagram illustrating the brightness-voltage characteristics of a light-emitting element in an example;

[0180] Fig.109 is a graph illustrating external quantum efficiency-luminance characteristics of a light-emitting element in an example;

[0181] Fig.110 is a diagram illustrating power efficiency-luminance characteristics of a light-emitting element in an example;

[0182] Fig.111 is a diagram illustrating an electric field emission spectrum of a light-emitting element in an example;

[0183] Fig.112 is a graph illustrating absorption spectra of compounds in Examples;

[0184] Fig.113 is a diagram illustrating power efficiency-luminance characteristics of a light-emitting element in an example;

[0185] Fig.114 is a diagram illustrating the brightness-voltage characteristics of a light-emitting element in an example;

[0186] Fig.115 is a graph illustrating external quantum efficiency-luminance characteristics of a light-emitting element in an example;

[0187] Fig.116 is a diagram illustrating an electric field emission spectrum of a light-emitting element in an example;

[0188] Fig.117 is a diagram illustrating light emission from a light emitting element in an embodiment;

[0189] Fig.118 is an NMR spectrum of the compound of one embodiment of the present invention;

[0190] Fig.119 It is a diagram illustrating the absorption spectrum and emission spectrum of the compound of one embodiment of the present invention. DETAILED DESCRIPTION

[0191] Hereinafter, the embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the following description, and its mode and details can be transformed into various forms without departing from the purpose and scope of the present invention. Therefore, the present invention should not be interpreted as being limited to the contents recorded in the embodiments shown below.

[0192] In addition, for ease of understanding, the position, size, range, etc. of each structure shown in the drawings and the like may not represent its actual position, size, range, etc. Therefore, the disclosed invention is not necessarily limited to the position, size, range, etc. disclosed in the drawings and the like.

[0193] In addition, in this specification, for the sake of convenience, ordinal numbers such as first and second are added, but they do not sometimes indicate the order of processes or the order of stacking. Therefore, for example, "first" can be appropriately replaced with "second" or "third" for description. In addition, the ordinal numbers recorded in this specification and the like are sometimes inconsistent with the ordinal numbers used to specify one embodiment of the present invention.

[0194] Note that in this specification and the like, when describing the embodiment of the invention using drawings, reference numerals may be used in common to represent the same components in different drawings.

[0195] In addition, depending on the situation or condition, in this specification, "film" and "layer" may be interchanged. For example, "conductive layer" may be replaced with "conductive film" in some cases. Also, "insulating film" may be replaced with "insulating layer" in some cases.

[0196] In this specification, the singlet excited state (S * ) refers to a singlet state having excitation energy. In addition, the lowest energy level of the singlet excited energy level (S1 level) refers to the lowest excitation energy level of the singlet excited state. In addition, the triplet excited state (T * ) refers to a triplet state having excitation energy. In addition, the lowest energy level of the triplet excited energy level (T1 energy level) refers to the excitation energy level of the lowest triplet excited state. In addition, in this specification, etc., "singlet excited state" and "singlet excited state energy level" sometimes refer to the lowest singlet excited state and S1 energy level, respectively. In addition, "triplet excited state" and "triplet excited state energy level" sometimes refer to the lowest triplet excited state and T1 energy level, respectively.

[0197] In addition, in this specification, etc., a fluorescent compound refers to a compound that emits light in the visible light region when returning from a singlet excited state to a ground state. A phosphorescent compound refers to a compound that emits light in the visible light region at room temperature when returning from a triplet excited state to a ground state. In other words, a phosphorescent compound refers to one of the compounds that can convert triplet excitation energy into visible light.

[0198] In addition, the phosphorescence energy or triplet excited state energy can be derived from the wavelength of the emission peak (including the shoulder peak) on the shortest wavelength side of the phosphorescence. In addition, the above-mentioned phosphorescence can be observed by time-resolved photoluminescence spectroscopy under a low temperature (e.g., 10K) environment. In addition, the luminescence energy of thermally activated delayed fluorescence can be derived from the wavelength of the emission peak (including the shoulder peak) on the shortest wavelength side of the thermally activated delayed fluorescence.

[0199] In addition, in this specification and the like, room temperature refers to any temperature between 0° C. and 40° C. inclusive.

[0200] In addition, in this specification, etc., the wavelength region of blue refers to a wavelength region of 400 nm or more and less than 505 nm, and blue luminescence is luminescence having at least one emission spectrum peak in this wavelength region. In addition, the wavelength region of green refers to a wavelength region of 505 nm or more and less than 580 nm, and green luminescence is luminescence having at least one emission spectrum peak in this wavelength region. In addition, the wavelength region of red refers to a wavelength region of 580 nm or more and less than 680 nm, and red luminescence is luminescence having at least one emission spectrum peak in this wavelength region.

[0201] Implementation Method 1

[0202] In this embodiment, refer to Figures 1A to 2B A light-emitting element according to one embodiment of the present invention will be described.

[0203] <Structural Example of Light Emitting Element>

[0204] First, we will refer to Figure 1A and Figure 1B The structure of a light-emitting element according to one embodiment of the present invention will be described.

[0205] Figure 1A It is a schematic cross-sectional view of a light emitting element 150 according to one embodiment of the present invention.

[0206] The light-emitting element 150 includes a pair of electrodes (electrode 101 and electrode 102 ) and an EL layer 100 between the pair of electrodes. The EL layer 100 includes at least a light-emitting layer 130 .

[0207] in addition, Figure 1A The EL layer 100 shown includes functional layers such as a hole injection layer 111 , a hole transport layer 112 , an electron transport layer 118 , and an electron injection layer 119 in addition to the light-emitting layer 130 .

[0208] In this embodiment, although the electrode 101 in a pair of electrodes is described as an anode and the electrode 102 is a cathode, the structure of the light-emitting element 150 is not limited thereto. In other words, the electrode 101 may be used as a cathode and the electrode 102 may be used as an anode, and the layers between the electrodes may be stacked in reverse order. In other words, the hole injection layer 111, the hole transport layer 112, the light-emitting layer 130, the electron transport layer 118, and the electron injection layer 119 may be stacked in sequence from the anode side.

[0209] Note that the structure of the EL layer 100 is not limited to Figure 1AThe structure shown in the figure only needs to include at least one selected from the hole injection layer 111, the hole transport layer 112, the electron transport layer 118 and the electron injection layer 119. Alternatively, the EL layer 100 may include a functional layer having the following functions: reducing the injection barrier of holes or electrons; improving the transportability of holes or electrons; hindering the transportability of holes or electrons; or suppressing the quenching phenomenon caused by the electrode. The functional layer may be a single layer or a structure in which a plurality of layers are stacked.

[0210] Figure 1B It is shown Figure 1A FIG. 1 is a schematic cross-sectional view of an example of the light emitting layer 130 shown. Figure 1B The light emitting layer 130 shown includes a host material 131 and a guest material 132. In addition, the host material 131 includes an organic compound 131_1 and an organic compound 131_2.

[0211] As the guest material 132, a light-emitting organic compound can be used. As the light-emitting organic compound, a substance capable of emitting phosphorescence (hereinafter, also referred to as a phosphorescent compound) is preferably used. In the following description, a structure in which a phosphorescent compound is used as the guest material 132 is described. Note that the guest material 132 may also be referred to as a phosphorescent compound.

[0212] <Light Emission Mechanism of Light Emitting Element>

[0213] Next, the light emitting mechanism of the light emitting layer 130 will be described below.

[0214] The organic compound 131_1 and the organic compound 131_2 included in the host material 131 in the light-emitting layer 130 form an exciplex.

[0215] As a combination of organic compound 131_1 and organic compound 131_2, any combination that can form an exciplex is sufficient, and preferably one of them is a compound having a function of transporting holes (hole transport properties) and the other is a compound having a function of transporting electrons (electron transport properties). In this case, it is easier to form a donor-acceptor type exciplex, and an exciplex can be formed efficiently.

[0216] In addition, as a combination of organic compound 131_1 and organic compound 131_2, the highest occupied molecular orbital (HOMO) energy level of one of organic compound 131_1 and organic compound 131_2 is preferably lower than that of the other, and the lowest unoccupied molecular orbital (LUMO) energy level of the one is preferably lower than that of the other.

[0217] For example, Figure 2A As shown in the energy band diagram of , when the organic compound 131_1 has an electron-transporting property and the organic compound 131_2 has a hole-transporting property, the HOMO energy level of the organic compound 131_1 is preferably lower than the HOMO energy level of the organic compound 131_2, and the LUMO energy level of the organic compound 131_1 is preferably lower than the LUMO energy level of the organic compound 131_2.

[0218] At this time, the excited radical complex formed by the organic compound 131_1 and the organic compound 131_2 becomes an excited radical complex having an excitation energy roughly equivalent to the energy difference between the LUMO energy level of the organic compound 131_1 and the HOMO energy level of the organic compound 131_2. In addition, the difference between the HOMO energy level of the organic compound 131_1 and the HOMO energy level of the organic compound 131_2 is preferably 0.1 eV or more, and more preferably 0.2 eV or more. Similarly, the difference between the LUMO energy level of the organic compound 131_1 and the LUMO energy level of the organic compound 131_2 is preferably 0.1 eV or more, and more preferably 0.2 eV or more. Due to this energy difference, electron carriers and hole carriers injected from a pair of electrodes (electrode 101 and electrode 102) are easily injected into the organic compound 131_1 and the organic compound 131_2, respectively, so it is preferred. Note that in Figure 2A In the above, Host (131_1) represents the organic compound 131_1, Host (131_2) represents the organic compound 131_2, Guest (132) represents the guest material 132, ΔE Ex represents the energy difference between the LUMO energy level of the organic compound 131_1 and the HOMO energy level of the organic compound 131_2, ΔE G represents the energy difference between the LUMO energy level and the HOMO energy level of the guest material 132 .

[0219] In addition, the HOMO energy level of the guest material 132 is preferably lower than the HOMO energy level of the organic compound 131_2, and the LUMO energy level of the guest material 132 is preferably higher than the LUMO energy level of the organic compound 131_1. That is, the energy difference (ΔE) between the LUMO energy level and the HOMO energy level of the guest material 132 is G ) is greater than the energy difference (ΔE) between the LUMO energy level of the organic compound 131_1 and the HOMO energy level of the organic compound 131_2 Ex ). Thus, formation of an exciplex between the guest material 132 and the organic compound 131_1 or the organic compound 131_2 can be suppressed.

[0220] For example, when the HOMO energy level of the guest material 132 is higher than the HOMO energy level of the organic compound 131_2, the material with the highest HOMO energy level among the materials included in the light-emitting layer 130 is the guest material 132, and the material with the lowest LUMO energy level among the materials included in the light-emitting layer 130 is the organic compound 131_1, it is possible that an exciplex is formed by the guest material 132 and the organic compound 131_1. In particular, the smaller the energy difference between the HOMO energy level of the guest material 132 and the LUMO energy level of the organic compound 131_1 is than the luminescent energy of the guest material, the easier it is to generate an exciplex formed by the guest material 132 and the organic compound 131_1. In this case, since the guest material 132 is not easy to generate an excited state alone, the luminous efficiency of the light-emitting element is reduced.

[0221] For example, when the LUMO energy level of the guest material 132 is lower than the LUMO energy level of the organic compound 131_2, the material with the lowest LUMO energy level among the materials included in the light-emitting layer 130 is the guest material 132, and the material with the highest HOMO energy level among the materials included in the light-emitting layer 130 is the organic compound 131_2, it is possible that an exciplex is formed by the guest material 132 and the organic compound 131_2. In particular, the smaller the energy difference between the LUMO energy level of the guest material 132 and the HOMO energy level of the organic compound 131_2 is than the luminescent energy of the guest material, the easier it is to generate an exciplex formed by the guest material 132 and the organic compound 131_2. In this case, since the guest material 132 is not easy to generate an excited state alone, the luminous efficiency of the light-emitting element is reduced.

[0222] However, in the light-emitting element of one embodiment of the present invention, since formation of an exciplex between the guest material 132 and the organic compound 131_1 or the organic compound 131_2 can be suppressed, a light-emitting element having high light emission efficiency can be manufactured.

[0223] In addition, since the HOMO energy level of the guest material 132 is lower than the HOMO energy level of the organic compound 131_2, the LUMO energy level of the guest material 132 is higher than the LUMO energy level of the organic compound 131_1. Among the carriers (holes and electrons) injected from the pair of electrodes (electrode 101 and electrode 102), holes injected from the anode are easily injected into the organic compound 131_2 in the light-emitting layer 130, and electrons injected from the cathode are easily injected into the organic compound 131_1.

[0224] From the above viewpoint, in one embodiment of the present invention, the HOMO energy level of the guest material 132 and the HOMO energy level of the organic compound 131_2 or the LUMO energy level of the guest material 132 and the LUMO energy level of the organic compound 131_1 may be equal. However, for the following reasons, the energy difference (ΔE G ) is preferably greater than the energy difference (ΔE) between the LUMO energy level of the organic compound 131_1 and the HOMO energy level of the organic compound 131_2 Ex ).

[0225] Due to the energy difference (ΔE) between the LUMO energy level of the organic compound 131_1 and the HOMO energy level of the organic compound 131_2 Ex ) is smaller than the energy difference between the LUMO energy level and the HOMO energy level of the organic compound 131_1 and the energy difference between the LUMO energy level and the HOMO energy level of the organic compound 131_2. Therefore, when the exciplex is formed, it is more energetically stable than when the organic compound 131_1 and the organic compound 131_2 form an excited state alone. In addition, because the energy difference (ΔE) between the LUMO energy level and the HOMO energy level of the guest material 132 G ) is greater than the energy difference (ΔE) between the LUMO energy level of the organic compound 131_1 and the HOMO energy level of the organic compound 131_2 Ex ), the exciplex formed by the organic compound 131_1 and the organic compound 131_2 is more energetically stable than an excited state formed by recombination of carriers (holes and electrons) injected into the light-emitting layer 130. Therefore, most of the excited states generated by the light-emitting layer 130 exist in the form of an exciplex formed by the organic compound 131_1 and the organic compound 131_2.

[0226] Since the guest material 132 is a phosphorescent material, it has the function of converting triplet excitation energy into luminescence. The energy of the triplet excited state is more stable than that of the singlet excited state. Therefore, the guest material 132 can present an energy smaller than the energy difference (ΔE) between the LUMO energy level and the HOMO energy level. G Here, the inventors found that if the luminescence energy presented by the guest material 132 or the migration energy calculated from the absorption spectrum is equal to or less than ΔE Ex , then even if the energy difference (ΔE G ) is greater than the energy difference (ΔE) between the LUMO energy level of the organic compound 131_1 and the HOMO energy level of the organic compound 131_2 Ex), the excitation energy can also be transferred from the exciplex formed by the organic compound 131_1 and the organic compound 131_2 to the guest material 132, so that light emission can be obtained from the guest material 132. G If the energy is greater than the luminescence energy of the guest material 132 or the transition energy calculated from the absorption spectrum, a current equivalent to ΔE is required to directly electrically excite the guest material 132. G However, in one embodiment of the present invention, the driving voltage is increased by the large electric energy equivalent to ΔE Ex (less than ΔE G ) electrical energy electrically excites the exciplex, and the energy transfer at this time obtains light emission from the guest material 132, thereby obtaining a guest material that emits light with high efficiency at a low voltage. That is, in ΔE G One embodiment of the present invention is useful when the energy is significantly greater than the luminescence energy exhibited by the guest material 132 or the transition energy calculated from the absorption spectrum (for example, when the guest material is a blue luminescent material).

[0227] In addition, when the guest material 132 contains a heavy metal, since the spin-orbit interaction (interaction between the spin angular momentum of an electron and the orbital angular momentum) promotes intersystem crossing between the singlet state and the triplet state, the migration between the singlet ground state and the triplet excited state in the guest material 132 is sometimes not forbidden. Therefore, the luminescence efficiency and the probability of absorption of the migration between the singlet ground state and the triplet excited state of the guest material 132 can be improved. Therefore, the guest material 132 preferably contains a metal element with a large spin-orbit interaction, and it is particularly preferred to contain a platinum group element (ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir) or platinum (Pt)), and it is particularly preferred to contain iridium. By containing iridium, the absorption probability of the direct migration between the singlet ground state and the triplet excited state can be increased, so it is preferred.

[0228] As described above, if the migration energy (abbreviated as ΔE) calculated from the absorption end of the guest material 132 G_abs ) is equal to or less than ΔE Ex , then even if the energy difference (ΔE G ) is greater than the energy difference (ΔE) between the LUMO energy level of the organic compound 131_1 and the HOMO energy level of the organic compound 131_2 Ex ), the excitation energy is efficiently transferred from the exciplex formed by the organic compound 131_1 and the organic compound 131_2 to the guest material 132. As a result, a light-emitting element with low driving voltage and high luminous efficiency can be obtained, which is one of the characteristics of one embodiment of the present invention. In this case, ΔE is satisfied.G_abs ≤ΔE Ex <ΔE G (ΔE G_abs = ΔE Ex Below, ΔE Ex Less than ΔE G ). Therefore, the migration energy (ΔE G_abs ) is smaller than the energy difference (ΔE) between the LUMO energy level and the HOMO energy level of the guest material 132 G ), the mechanism of one embodiment of the present invention is preferred. In other words, the energy difference (ΔE G ) is greater than the migration energy (ΔE G_abs ), the mechanism of one embodiment of the present invention is preferred. Specifically, the energy difference (ΔE) between the LUMO level and the HOMO level of the guest material 132 G ) is preferably greater than the migration energy (ΔE) calculated from the absorption end of the guest material 132 G_abs ) is greater than 0.4 eV. In addition, because the luminescence energy presented by the guest material 132 is equal to or less than ΔE G_abs , so the energy difference (ΔE G ) is preferably 0.4 eV or more greater than the luminescent energy exhibited by the guest material 132. The luminescent energy can be derived from the peak wavelength (maximum or including the shoulder) on the shortest wavelength side of the emission spectrum.

[0229] The shorter the emission wavelength of the guest material 132 (the greater the emission energy), the greater the energy difference (ΔE G ) is larger, so more energy is required when electrically exciting the guest material. However, if the migration energy (ΔE G_abs ) is equal to or less than ΔE Ex According to the present invention, the G ΔE Ex The energy of the guest material 132 is used to excite the guest material 132, thereby reducing the power consumption of the light-emitting element. Therefore, the migration energy (ΔE G_abs ) and the energy difference (ΔE G ) is large (i.e., particularly in the case of a guest material that emits blue light), the effect of the mechanism of one embodiment of the present invention is clearly seen.

[0230] Note that the migration energy (ΔE G_abs ) becomes smaller, the luminescent energy presented by the guest material 132 also becomes smaller, so it is difficult to obtain high-energy luminescence such as blue luminescence. G_abs With ΔE G When the difference is too large, it is difficult to obtain high-energy light emission such as blue light emission.

[0231] Thus, the energy difference (ΔE G ) is preferably greater than the migration energy (ΔE) calculated from the absorption end of the guest material 132 G_abs ) is greater than 0.4 eV and less than 0.8 eV, and more preferably greater than 0.5 eV and less than 0.8 eV. In addition, since the luminescence energy presented by the guest material 132 is equal to or less than ΔE G_abs , so the energy difference (ΔE G ) is preferably 0.4 eV or more and 0.8 eV or less than the luminescence energy exhibited by the guest material 132, and more preferably 0.5 eV or more and 0.8 eV or less.

[0232] In addition, the difference between the LUMO energy level of the guest material 132 and the LUMO energy level of the organic compound 131_1 is preferably 0.05 eV or more, more preferably 0.1 eV or more, and further preferably 0.2 eV or more. In addition, the difference between the HOMO energy level of the guest material 132 and the HOMO energy level of the organic compound 131_2 is preferably 0.05 eV or more, more preferably 0.1 eV or more, and further preferably 0.2 eV or more. By satisfying the above conditions, electron carriers and hole carriers are easily injected into the organic compound 131_1 and the organic compound 131_2, so it is preferred.

[0233] In addition, the HOMO energy level of the guest material 132 may be higher or lower than the HOMO energy level of the organic compound 131_1. In addition, the LUMO energy level of the guest material 132 may be higher or lower than the LUMO energy level of the organic compound 131_2.

[0234] In addition, according to the relationship between the LUMO energy level and the HOMO energy level, as a combination of the organic compound 131_1 and the organic compound 131_2, the oxidation potential of one of the organic compound 131_1 and the organic compound 131_2 is preferably higher than the other, and the reduction potential of the one is preferably higher than the other.

[0235] For example, when the organic compound 131_1 has an electron-transporting property and the organic compound 131_2 has a hole-transporting property, the oxidation potential of the organic compound 131_1 is preferably higher than that of the organic compound 131_2, and the reduction potential of the organic compound 131_1 is preferably higher than that of the organic compound 131_2. The oxidation potential and the reduction potential are measured by using a cyclic voltammetry (CV) method.

[0236] The oxidation potential of the guest material 132 is preferably higher than that of the organic compound 131_2, and the reduction potential of the guest material 132 is preferably lower than that of the organic compound 131_1. By satisfying the above conditions, formation of an exciplex between the guest material 132 and the organic compound 131_1 or the organic compound 131_2 can be suppressed as described above.

[0237] In addition, when the combination of organic compound 131_1 and organic compound 131_2 is a combination of a compound having hole transport properties and a compound having electron transport properties, the balance of carriers can be easily controlled by adjusting their mixing ratio. Specifically, the compound having hole transport properties: the compound having electron transport properties is preferably in the range of 1:9 to 9:1 (weight ratio). In addition, by having this structure, the balance of carriers can be easily controlled, thereby easily controlling the carrier recombination region.

[0238] The exciplex formed by the organic compound 131_1 and the organic compound 131_2 has a HOMO in one organic compound and a LUMO in the other organic compound, so the overlap between the HOMO and the LUMO is extremely small. That is, in the exciplex, the difference between the singlet excitation energy level and the triplet excitation energy level is small. Therefore, in the exciplex formed by the organic compound 131_1 and the organic compound 131_2, the difference between the singlet excitation energy level and the triplet excitation energy level is preferably greater than 0 eV and less than 0.2 eV.

[0239] Here, Figure 2B 1 shows the energy level correlation of the organic compound 131_1, the organic compound 131_2, and the guest material 132 in the light-emitting layer 130. Note that Figure 2B The records and symbols in the table represent the following:

[0240] Host (131_1): host material (organic compound 131_1);

[0241] Host (131_2): host material (organic compound 131_2);

[0242] Guest (132): guest material 132 (phosphorescent compound);

[0243] S PH : S1 energy level of the host material (organic compound 131_1);

[0244] T PH : T1 energy level of the host material (organic compound 131_1);

[0245] S PG : S1 energy level of guest material 132 (phosphorescent compound);

[0246] T PG : T1 energy level of guest material 132 (phosphorescent compound);

[0247] S PE : S1 energy level of the exciplex; and

[0248] T PE : T1 energy level of the exciplex.

[0249] In the light-emitting element of one embodiment of the present invention, an exciplex is formed by the organic compound 131_1 and the organic compound 131_2 included in the light-emitting layer 130. The lowest singlet excitation energy level (S PE ) and the lowest triplet excitation energy level of the exciplex (T PE ) are adjacent to each other (refer to Figure 2B Path E 7 ).

[0250] An exciplex is an excited state formed by two substances. In the case of light excitation, the exciplex is formed by the interaction of a substance in an excited state with another substance in a ground state. When returning to the ground state by emitting light, the two substances forming the exciplex respectively restore the state of the original substances. In the case of electrical excitation, when one substance is in an excited state, it quickly interacts with another substance to form an exciplex. Alternatively, an exciplex can be quickly formed by having one substance receive holes and the other substance receive electrons. At this time, an exciplex can be formed in a way that no single substance forms an excited state in the two substances, so most of the excited states formed in the light-emitting layer 130 can exist as an exciplex. The excitation energy level (S) of the exciplex is E or T E ) is greater than the singlet excitation energy level (S) of the host material (organic compound 131_1 and organic compound 131_2) that forms the exciplex. PH ) is low, the excited state of the host material 131 can be formed with lower excitation energy. As a result, the driving voltage of the light-emitting element 150 can be reduced.

[0251] Then, the singlet excited energy level (SPE ) and triplet excitation level (T PE ) are transferred to the lowest energy level (T PG ) to obtain luminescence (refer to Figure 2B Path E 8 、E 9 ).

[0252] In addition, the triplet excitation energy level (T PE ) is preferably higher than the triplet excitation energy level (T PG ). Thus, the singlet excitation energy and triplet excitation energy of the generated exciplex can be obtained from the singlet excitation energy level (S PE ) and triplet excitation level (T PE ) is transferred to the triplet excited energy level (T PG ).

[0253] When the light-emitting layer 130 has the above structure, light emission from the guest material 132 (phosphorescent compound) in the light-emitting layer 130 can be obtained efficiently.

[0254] In this specification, the above-mentioned path E may be referred to as 7 、E 8 and E 9 The process of exciplex-triplet energy transfer is called ExTET (Exciplex-Triplet Energy Transfer). In other words, in the light-emitting layer 130, the excitation energy is supplied from the exciplex to the guest material 132. In this case, it is not necessary to transfer the energy from T PE To S PE The efficiency of anti-system crossing and the PE The luminescence quantum yield is high, so a wider variety of materials can be selected.

[0255] The above reaction can be represented by the following general formulae (G11) to (G13).

[0256] D + +A - →(D·A) * (G11)

[0257] (D.A) * +G→D+A+G * (G12)

[0258] G * →G+hν (G13)

[0259] In the reaction represented by the general formula (G11), one of the organic compound 131_1 and the organic compound 131_2 receives the hole (D + ), and the other accepts electrons (A - ), whereby the organic compound 131_1 and the organic compound 131_2 generate an exciplex ((D·A) ＊ ). In the general formula (G12), the exciplex ((D·A) ＊ ) to the guest material 132 (G), thereby generating an excited state of the guest material 132 (G ＊ ). Then, as shown in the general formula (G13), the guest material 132 in the excited state emits light (hν).

[0260] Note that in order to efficiently transfer the excitation energy from the exciplex to the guest material 132, the triplet excitation energy level of the exciplex is preferably lower than the triplet excitation energy level of each organic compound (organic compound 131_1 and organic compound 131_2) in the host material forming the exciplex. Thus, quenching of the triplet excitation energy of the exciplex formed by each organic compound is less likely to occur, and energy transfer to the guest material 132 occurs efficiently.

[0261] When the organic compound 131_2 has a strong donor skeleton, holes injected into the light-emitting layer 130 are easily injected into the organic compound 131_2 and transferred. When the organic compound 131_1 has a strong acceptor skeleton, electrons injected into the light-emitting layer 130 are easily injected into the organic compound 131_1 and transferred. Thus, the organic compound 131_1 and the organic compound 131_2 easily form an exciplex.

[0262] By making the light-emitting layer 130 have the above structure, light emission from the guest material 132 in the light-emitting layer 130 can be obtained efficiently.

[0263] <Energy transfer mechanism>

[0264] Next, the factors controlling the energy transfer process between the molecules of the host material 131 and the guest material 132 are described. As a mechanism of energy transfer between molecules, the Foster Note that although the energy transfer process between the host material 131 and the guest material 132 molecules is described here, the same is true when the host material 131 is an exciplex.

[0265] Foster Mechanism

[0266] In the Förster mechanism, direct contact between molecules is not required for energy transfer, and energy transfer occurs through the resonance phenomenon of dipole oscillation between the host material 131 and the guest material 132. Through the resonance phenomenon of dipole oscillation, the host material 131 supplies energy to the guest material 132, and the excited host material 131 becomes the ground state, and the ground state guest material 132 becomes the excited state. In addition, Formula 1 shows the rate constant k of the Förster mechanism: h*→g .

[0267]

[0268] In formula 1, ν represents the oscillation number, f' h (ν) represents the normalized emission spectrum of the host material 131 (equivalent to the fluorescence spectrum when energy transfer from the singlet excited state is considered, and equivalent to the phosphorescence spectrum when energy transfer from the triplet excited state is considered), ε g (ν) represents the molar absorption coefficient of the guest material 132, N represents the Avogadro number, n represents the refractive index of the medium, R represents the molecular distance between the host material 131 and the guest material 132, τ represents the lifetime of the measured excited state (fluorescence lifetime or phosphorescence lifetime), c represents the speed of light, φ represents the luminescence quantum yield (equivalent to the fluorescence quantum yield when considering the energy transfer from the singlet excited state, and equivalent to the phosphorescence quantum yield when considering the energy transfer from the triplet excited state), K 2 A coefficient (0 to 4) representing the orientation of the transition dipole moments of the host material 131 and the guest material 132. In addition, in the random orientation, K 2 =2 / 3.

[0269] Dexter Mechanism

[0270] In the Dexter mechanism, the host material 131 and the guest material 132 are close to the contact effective distance that causes the overlap of orbits, and energy transfer occurs by exchanging the electrons of the host material 131 in the excited state and the electrons of the guest material 132 in the ground state. In addition, the rate constant k of the Dexter mechanism is shown in equation 2: h*→g .

[0271]

[0272] In equation 2, h represents Planck's constant, K represents a constant with energy dimension, ν represents the oscillation number, and f' h (v) represents the normalized emission spectrum of the host material 131 (equivalent to the fluorescence spectrum when energy transfer from the singlet excited state is considered, and equivalent to the phosphorescence spectrum when energy transfer from the triplet excited state is considered), ε' g(ν) represents the normalized absorption spectrum of the guest material 132 , L represents the effective molecular radius, and R represents the molecular distance between the host material 131 and the guest material 132 .

[0273] Here, the energy transfer efficiency φ from the host material 131 to the guest material 132 ET It is expressed as formula 3. In the formula, k r k represents the rate constant of the light emission process of the host material 131 (equivalent to fluorescence when energy transfer from a singlet excited state is considered, and equivalent to phosphorescence when energy transfer from a triplet excited state is considered). n represents the rate constant of the non-luminescent process (thermal deactivation or intersystem crossing) of the host material 131, and τ represents the measured lifetime of the excited state of the host material 131.

[0274]

[0275] From equation 3, we can see that by increasing the energy transfer rate constant k h*→g , other competing rate constants k r +k n (=1 / τ) becomes relatively small, which can improve the energy transfer efficiency φ ET .

[0276] Concepts for enhancing energy transfer

[0277] In energy transfer based on the Förster mechanism, the energy transfer efficiency Quantum yield The wavelength of the light emitting element 132 (the fluorescence quantum yield when explaining the energy transfer from the singlet excited state, and the phosphorescence quantum yield when explaining the energy transfer from the triplet excited state) is preferably high. In addition, the overlap between the emission spectrum of the host material 131 (the fluorescence spectrum when explaining the energy transfer from the singlet excited state) and the absorption spectrum of the guest material 132 (equivalent to the absorption of the transition from the singlet ground state to the triplet excited state) is preferably large. Furthermore, the molar absorption coefficient of the guest material 132 is preferably high. This means that the emission spectrum of the host material 131 overlaps with the absorption band present on the longest wavelength side of the guest material 132.

[0278] In addition, in the energy transfer based on the Dexter mechanism, in order to increase the rate constant k h*→g The overlap between the emission spectrum of the host material 131 (a fluorescence spectrum when explaining energy transfer from a singlet excited state, and a phosphorescence spectrum when explaining energy transfer from a triplet excited state) and the absorption spectrum of the guest material 132 (absorption corresponding to the transition from a singlet ground state to a triplet excited state) is preferably large. Therefore, the optimization of energy transfer efficiency can be achieved by overlapping the emission spectrum of the host material 131 with the absorption band present on the longest wavelength side of the guest material 132.

[0279] Similar to the energy transfer from the host material 131 to the guest material 132 , energy transfer based on both the Förster mechanism and the Dexter mechanism also occurs in the energy transfer process from the exciplex to the guest material 132 .

[0280] Thus, one embodiment of the present invention provides a light-emitting element, which includes, as a host material 131, a combination of an organic compound 131_1 and an organic compound 131_2 that form an exciplex serving as an energy donor capable of efficiently transferring energy to a guest material 132. The exciplex formed by the organic compound 131_1 and the organic compound 131_2 can be formed with an excitation energy lower than that of the excited state of the single organic compound 131_1 and the single organic compound 131_2. Thus, the driving voltage of the light-emitting element 150 can be reduced. Furthermore, in order to facilitate energy transfer from the singlet excitation energy level of the exciplex to the triplet excitation energy level of the guest material 132 used as an energy acceptor, it is preferred that the emission spectrum of the exciplex overlaps with the absorption band of the guest material 132 that appears on the longest wavelength side (low energy side). Thus, the generation efficiency of the triplet excited state of the guest material 132 can be improved. Since the excited complex generated in the light-emitting layer 130 has the characteristic that the singlet excitation energy level and the triplet excitation energy level are close, by making the emission spectrum of the excited complex overlap with the absorption band presented on the longest wavelength side (low energy side) of the guest material 132, energy transfer from the triplet excitation energy level of the excited complex to the triplet excitation energy level of the guest material 132 can be easily carried out.

[0281] <Materials>

[0282] Next, components of a light-emitting element according to one embodiment of the present invention will be described in detail below.

[0283] Luminous Layer

[0284] In the material weight ratio of the light-emitting layer 130, the host material 131 accounts for the largest proportion, and the guest material 132 (phosphorescent compound) is dispersed in the host material 131. The T1 energy level of the host material 131 (organic compound 131_1 and organic compound 131_2) of the light-emitting layer 130 is preferably higher than the T1 energy level of the guest material (guest material 132) of the light-emitting layer 130.

[0285] As the organic compound 131_1, a material having a higher electron-transport property than a hole-transport property can be used, and preferably a material having a 1×10 -6 cm 2 / Vs or more of the electron mobility. As a material that easily receives electrons (a material with electron transport properties), nitrogen-containing heteroaromatic compounds and compounds including π-electron-deficient aromatic heterocyclic skeletons and zinc or aluminum metal complexes can be used. As examples of compounds including π-electron-deficient aromatic heterocyclic skeletons, oxadiazole derivatives, triazole derivatives, benzimidazole derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, phenanthroline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, triazine derivatives, etc. can be cited. As examples of zinc or aluminum metal complexes, metal complexes including quinoline ligands, benzoquinoline ligands, oxazole ligands or thiazole ligands can be cited.

[0286] Specifically, examples of the metal complex having a quinoline skeleton or a benzoquinoline skeleton include tris(8-hydroxyquinoline)aluminum(III) (abbreviated as Alq), tris(4-methyl-8-hydroxyquinoline)aluminum(III) (abbreviated as Almq), 3 ), bis(10-hydroxybenzo[h]quinolinolato)beryllium(II) (abbreviated as: BeBq 2), bis(2-methyl-8-hydroxyquinoline)(4-phenylphenol)aluminum(III) (abbreviated as BAlq), bis(8-hydroxyquinoline)zinc(II) (abbreviated as Znq), etc. In addition, metal complexes having oxazolyl or thiazole ligands such as bis[2-(2-benzoxazolyl)phenol]zinc(II) (abbreviated as ZnPBO) and bis[2-(2-benzothiazolyl)phenol]zinc(II) (abbreviated as ZnBTZ) can also be used. Furthermore, in addition to the metal complex, 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazole-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazole-2-yl)phenyl]-9H-carbazole (abbreviation: CO11), 3-(4-biphenyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 9-[4-(4,5-diphenyl-4H-1,2,4-triazol-3-yl)phenyl]-9H-carbazole (abbreviated as: CzTAZ1), 2,2',2"-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviated as: TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviated as: mDBTBIm-II), bathophenanthroline (abbreviated as: BPhen), bathocuproin (abbreviated as: BCP) and other heterocyclic compounds;2-[3-(dibenzothiophene-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviated as 2mDBTPDBq-II), 2-[3'-(dibenzothiophene-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviated as 2mDBTBPDBq-II), 2-[3'-(9H-carbazole-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviated as 2mCzBPDBq), 2-[4-(3,6-diphenyl 2-[3-(dibenzothiophene-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviated as 2CzPDBq-III), 7-[3-(dibenzothiophene-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviated as 7mDBTPDBq-II), 6-[3-(dibenzothiophene-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviated as 6mDBTPDBq-II), 2-[3-(3,9'-bi-9H-carbazole-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviated as 2CzPDBq-III), 7-[3-(dibenzothiophene-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviated as 7mDBTPDBq-II), and [f, h]quinoxaline (abbreviation: 2mCzCzPDBq), 4,6-bis[3-(phenanthrene-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(4-dibenzothienyl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm) and the like; heterocyclic compounds having a diazine skeleton, such as 2-{4-[3-( Heterocyclic compounds having a triazine skeleton such as [N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviated as PCCzPTzn); heterocyclic compounds having a pyridine skeleton such as 3,5-bis[3-(9H-carbazole-9-yl)phenyl]pyridine (abbreviated as 35DCzPPy); heteroaromatic compounds such as 4,4'-bis(5-methylbenzoxazolyl-2-yl)stilbene (abbreviated as BzOs). Among the above heterocyclic compounds, heterocyclic compounds having a triazine skeleton, a diazine skeleton (pyrimidine, pyrazine, pyridazine) or a pyridine skeleton are stable and have good reliability, so they are preferred. In particular, heterocyclic compounds having the above skeletons have high electron transport properties, which also helps to reduce the driving voltage. In addition, polymer compounds such as poly(2,5-pyridinediyl) (abbreviated as PPy), poly[(9,9-dihexylfluorene-2,7-diyl)-co-(pyridine-3,5-diyl)] (abbreviated as PF-Py), and poly[(9,9-dioctylfluorene-2,7-diyl)-co-(2,2'-bipyridine-6,6'-diyl)] (abbreviated as PF-BPy) can also be used. The substances described here mainly have an electron mobility of 1×10; - 6 cm 2 Note that any substance other than the above substances may be used as long as it has a higher electron-transporting property than a hole-transporting property.

[0287] As the organic compound 131_2, it is preferred to use a substance that can form an exciplex with the organic compound 131_1. Specifically, the organic compound 131_2 preferably includes a skeleton with high donor properties such as a π-electron-rich aromatic heterocyclic skeleton or an aromatic amine skeleton. As compounds including a π-electron-rich aromatic heterocyclic skeleton, heteroaromatic compounds such as dibenzothiophene derivatives, dibenzofuran derivatives, and carbazole derivatives can be cited. At this time, it is preferred to select the organic compound 131_1, the organic compound 131_2, and the guest material 132 (phosphorescent compound) in such a way that the luminescence peak of the exciplex formed by the organic compound 131_1 and the organic compound 131_2 overlaps with the absorption band of the triple MLCT (metal to ligand charge transfer: Metal to Ligand Charge Transfer) transition of the guest material 132 (phosphorescent compound) (specifically, the absorption band on the longest wavelength side). Thereby, a light-emitting element with significantly improved luminescence efficiency can be realized. Note that, in the case of using a thermally activated delayed fluorescent material instead of a phosphorescent compound, the absorption band on the longest wavelength side is preferably an absorption band of a singlet state.

[0288] In addition, as the organic compound 131_2, the following hole-transporting materials can be used.

[0289] As the hole transport material, a material having a hole transport property higher than an electron transport property can be used, and preferably a material having a 1×10 -6 cm 2 / Vs or higher. Specifically, aromatic amines, carbazole derivatives, aromatic hydrocarbons, stilbene derivatives, etc. can be used. The hole transport material may also be a polymer compound.

[0290] As aromatic amine compounds that can be used as materials with high hole-transporting properties, there are N,N'-di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviation: DTDPPA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), N,N'-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (abbreviation: DNTPD), 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), etc.

[0291] In addition, specific examples of carbazole derivatives include 3-[N-(4-diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole (abbreviated as PCzDPA1), 3,6-bis[N-(4-diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole (abbreviated as PCzDPA2), 3,6-bis[N-(4-diphenylaminophenyl)-N-(1-naphthyl)amino]-9-phenylcarbazole (abbreviated as PCzDPA2), and 3,6-bis[N-(4-diphenylaminophenyl)-N-(1-naphthyl)amino]-9-phenylcarbazole (abbreviated as PCzDPA1). CzTPN2), 3-[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviated as: PCzPCA1), 3,6-bis[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviated as: PCzPCA2), 3-[N-(1-naphthyl)-N-(9-phenylcarbazole-3-yl)amino]-9-phenylcarbazole (abbreviated as: PCzPCN1), etc.

[0292] In addition, examples of carbazole derivatives include 4,4'-di(N-carbazolyl)biphenyl (abbreviation: CBP), 1,3,5-tri[4-(N-carbazolyl)phenyl]benzene (abbreviation: TCPB), 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA), and 1,4-bis[4-(N-carbazolyl)phenyl]-2,3,5,6-tetraphenylbenzene.

[0293] Examples of aromatic hydrocarbons include 2-tert-butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA), 2-tert-butyl-9,10-di(1-naphthyl)anthracene, 9,10-bis(3,5-diphenylphenyl)anthracene (abbreviation: DPPA), 2-tert-butyl-9,10-bis(4-phenylphenyl)anthracene (abbreviation: t-BuDBA), 9,10-di(2-naphthyl)anthracene (abbreviation: DNA), 9,10-diphenylanthracene (abbreviation: DPAnth), 2-tert-butylanthracene (abbreviation: t-BuAnth), 9,10-bis(4-methyl-1-naphthyl)anthracene (abbreviation: DMNA), and 2-tert-butylanthracene (abbreviation: t-BuAnth). ), 2-tert-butyl-9,10-bis[2-(1-naphthyl)phenyl]anthracene, 9,10-bis[2-(1-naphthyl)phenyl]anthracene, 2,3,6,7-tetramethyl-9,10-di(1-naphthyl)anthracene, 2,3,6,7-tetramethyl-9,10-di(2-naphthyl)anthracene, 9,9'-bianthracene, 10,10'-diphenyl-9,9'-bianthracene, 10,10'-bis(2-phenylphenyl)-9,9'-bianthracene, 10,10'-bis[(2,3,4,5,6-pentaphenyl)phenyl]-9,9'-bianthracene, anthracene, tetracene, rubrene, perylene, 2,5,8,11-tetra(tert-butyl)perylene, etc. In addition, pentacene, coronene, etc. can also be used. In this way, it is more preferable to use a 1×10 -6 cm 2An aromatic hydrocarbon having a hole mobility of 1 / Vs or higher and a carbon number of 14 or more and 42 or less.

[0294] Note that the aromatic hydrocarbon may also have a vinyl skeleton. Examples of the aromatic hydrocarbon having a vinyl group include 4,4'-bis(2,2-diphenylvinyl)biphenyl (abbreviation: DPVBi) and 9,10-bis[4-(2,2-diphenylvinyl)phenyl]anthracene (abbreviation: DPVPA).

[0295] In addition, high molecular weight compounds such as poly(N-vinylcarbazole) (abbreviation: PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA), poly[N-(4-{N'-[4-(4-diphenylamino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide] (abbreviation: PTPDMA), and poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine] (abbreviation: Poly-TPD) can also be used.

[0296] In addition, as a material with high hole transport properties, for example, 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviated as: NPB or α-NPD), N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviated as: TPD), 4,4',4"-tri(carbazol-9-yl)triphenylamine (abbreviated as: TCTA), 4,4',4"-tri[N-(1-naphthyl)-N-phenylamino]triphenylamine (abbreviated as: 1'-TNATA), 4,4',4"-tri(N,N-diphenylamino)triphenylamine (abbreviated as: TDATA), 4,4',4"-tri[N-(3-methylphenyl)-N-phenylamino]triphenylamine amine (abbreviation: MTDATA), 4,4'-bis[N-(spiro-9,9'-bifluoren-2-yl)-N-phenylamino]biphenyl (abbreviation: BSPB), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), N-(9,9-dimethyl-9H-fluoren-2-yl)-N-{9,9-dimethyl-2-[N'-phenyl-N'-(9,9-dimethyl-9H-fluoren-2-yl)amino]-9H-fluoren-7-yl}phenylamine (abbreviation: DFLADFL), N-(9,9-dimethyl-2-diphenylamino-9H-fluoren-7-yl)diphenylamine amine (abbreviation: DPNF), 2-[N-(4-diphenylaminophenyl)-N-phenylamino]spiro-9,9'-bifluorene (abbreviation: DPASF), 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4"-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBBi1BP), 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: PCNBB), 4-phenyldiphenyl-(9-phenyl-9H- carbazole-3-yl)amine (abbreviation: PCA1BP), N,N'-bis(9-phenylcarbazole-3-yl)-N,N'-diphenylbenzene-1,3-diamine (abbreviation: PCA2B), N,N',N"-triphenyl-N,N',N"-tri(9-phenylcarbazole-3-yl)benzene-1,3,5-triamine (abbreviation: PCA3B), N-(4-biphenyl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-9-phenyl-9H-carbazole-3-amine (abbreviation: PCBiF), N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: PCBBiF), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]spiro-9,9'-bifluoren-2-amine (abbreviation: PCBASF), 2-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]spiro-9,9'-bifluoren-2-amine (abbreviation: PCASF), 2,7 -Bis[N-(4-diphenylaminophenyl)-N-phenylamino]-spiro-9,9'-bifluorene (abbreviation: DPA2SF), N-[4-(9H-carbazole-9-yl)phenyl]-N-(4-phenyl)phenylaniline (abbreviation: YGA1BP), N,N'-bis[4-(carbazole-9-yl)phenyl]-N,N'-diphenyl-9,9-dimethylfluorene-2,7-diamine (abbreviation: YGA2F) and other aromatic amine compounds, etc. In addition, 3-[4-(1-naphthyl)-phenyl]-9-phenyl-9H-carbazole (abbreviated as PCPN), 3-[4-(9-phenanthrenyl)-phenyl]-9-phenyl-9H-carbazole (abbreviated as PCPPn), 3,3'-bis(9-phenyl-9H-carbazole) (abbreviated as PCCP), 1,3-bis(N-carbazolyl)benzene (abbreviated as mCP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviated as PCPPn) can be used. Abbreviation: CzTP), 3,6-bis(9H-carbazole-9-yl)-9-phenyl-9H-carbazole (abbreviation: PhCzGI), 2,8-bis(9H-carbazole-9-yl)-dibenzothiophene (abbreviation: Cz2DBT), 4-{3-[3-(9-phenyl-9H-fluorene-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II), 4,4',4"-(benzene-1,3,5-triyl)tri (dibenzofuran) (abbreviation: DBF3P-II), 1,3,5-tris(dibenzothiophene-4-yl)-benzene (abbreviation: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluorene-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), 4-[4-(9-phenyl-9H-fluorene-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV), 4-[3-(triphenylene-2-yl)phenyl]dibenzothiophene (abbreviation: mDBTPTp-II) and other amine compounds, carbazole compounds, thiophene compounds, furan compounds, fluorene compounds, triphenylene compounds, phenanthrene compounds, etc. Among them, compounds with pyrrole skeletons, furan skeletons, thiophene skeletons, and aromatic amine skeletons are stable and have good reliability, so they are preferred. Compounds with the above skeletons have high hole transport properties and also help to reduce the driving voltage. ,

[0297] As guest material 132 (phosphorescent compound), iridium, rhodium, platinum organic metal complexes or metal complexes can be cited, among which organic iridium complexes, such as iridium ortho-metal complexes, are preferred. As ortho-metallated ligands, 4H-triazole ligands, 1H-triazole ligands, imidazole ligands, pyridine ligands, pyrimidine ligands, pyrazine ligands and isoquinoline ligands can be cited. As metal complexes, platinum complexes with porphyrin ligands can be cited.

[0298] In addition, the organic compound 131_1, the organic compound 131_2, and the guest material 132 (phosphorescent compound) are preferably selected so that the LUMO energy level of the guest material 132 (phosphorescent compound) is higher than the LUMO energy level of the organic compound 131_1 and the HOMO energy level of the guest material 132 is lower than the HOMO energy level of the organic compound 131_2. Thus, a light-emitting element having high luminous efficiency and capable of being driven at a low voltage can be manufactured.

[0299] As a substance having a light emission peak in the blue or green wavelength range, for example, tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazol-3-yl-κN2]phenyl-κC}iridium(III) (abbreviation: Ir(mpptz-dmp) 3 ), tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazole)iridium(III) (abbreviated as: Ir(Mptz) 3 ), tris[4-(3-biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazole]iridium(III) (abbreviated as: Ir(iPrptz-3b) 3 ), tris[3-(5-biphenyl)-5-isopropyl-4-phenyl-4H-1,2,4-triazole]iridium(III) (abbreviated as: Ir(iPr5btz) 3 ) and other organic metal iridium complexes with a 4H-triazole skeleton; tris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazole]iridium(III) (abbreviated as: Ir(Mptz1-mp) 3 ), tris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazole)iridium(III) (abbreviated as: Ir(Prptz1-Me) 3 ) and other organometallic iridium complexes with a 1H-triazole skeleton; fac-tris[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]iridium(III) (abbreviated as: Ir(iPrpmi) 3 ), tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(III) (abbreviated as: Ir(dmpimpt-Me)3 ) and other organometallic iridium complexes having an imidazole skeleton; and bis[2-(4',6'-difluorophenyl)pyridinium-N,C 2' ]iridium(III)tetrakis(1-pyrazolyl)borate (abbreviated as FIr6), bis[2-(4',6'-difluorophenyl)pyridinium-N,C 2' ]iridium(III) picolinate (abbreviated as FIrpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinium-N,C 2' Iridium(III) picolinate (abbreviated as Ir(CF 3 ppy) 2 (pic)), bis[2-(4',6'-difluorophenyl)pyridinium-N,C 2' ] Iridium (III) acetylacetonate (abbreviated as FIr(acac)) and other organic metal iridium complexes with phenylpyridine derivatives having electron-withdrawing groups as ligands. Among the above metal complexes, organic metal iridium complexes having nitrogen-containing five-membered heterocyclic skeletons such as 4H-triazole skeleton, 1H-triazole skeleton and imidazole skeleton are particularly preferred because of their high triplet excitation energy and excellent reliability and luminous efficiency.

[0300] Examples of substances having a light emission peak in the green or yellow wavelength range include tris(4-methyl-6-phenylpyrimidine)iridium(III) (abbreviation: Ir(mppm) 3 ), tri(4-tert-butyl-6-phenylpyrimidine)iridium(III) (abbreviated as: Ir(tBuppm) 3 ), (acetylacetonate)bis(6-methyl-4-phenylpyrimidine)iridium(III) (abbreviated as: Ir(mppm) 2 (acac)), (acetylacetonate)bis(6-tert-butyl-4-phenylpyrimidine)iridium(III) (abbreviated as: Ir(tBuppm) 2 (acac)), (acetylacetonato)bis[4-(2-norbornyl)-6-phenylpyrimidine]iridium(III) (abbreviation: Ir(nbppm) 2 (acac)), (acetylacetonato)bis[5-methyl-6-(2-methylphenyl)-4-phenylpyrimidine]iridium(III) (abbreviation: Ir(mpmppm) 2 (acac)), (acetylacetonato)bis{4,6-dimethyl-2-[6-(2,6-dimethylphenyl)-4-pyrimidinyl-κN3]phenyl-κC}iridium(III) (abbreviated as: Ir(dmppm-dmp) 2 (acac)), (acetylacetonate)bis(4,6-diphenylpyrimidine)iridium(III) (abbreviated as: Ir(dppm) 2(acac)) and other organometallic iridium complexes with a pyrimidine skeleton, (acetylacetonate)bis(3,5-dimethyl-2-phenylpyrazine)iridium(III) (abbreviated as Ir(mppr-Me) 2 (acac)), (acetylacetonate)bis(5-isopropyl-3-methyl-2-phenylpyrazine)iridium(III) (abbreviated as: Ir(mppr-iPr) 2 (acac)) and other organic metal iridium complexes with pyrazine skeletons, tris(2-phenylpyridine-N,C 2' )Iridium(III) (Abbreviation: Ir(ppy) 3 ), bis(2-phenylpyridinium-N,C 2' )Iridium(III) acetylacetonate (abbreviated as: Ir(ppy) 2 (acac)), bis(benzo[h]quinoline)iridium(III)acetylacetonate (abbreviated as: Ir(bzq) 2 (acac)), tris(benzo[h]quinoline)iridium(III) (abbreviation: Ir(bzq) 3 ), tris(2-phenylquinoline-N,C 2′ )Iridium(III) (Abbreviation: Ir(pq) 3 ), bis(2-phenylquinoline-N,C 2' )iridium(III)acetylacetonate (abbreviated as: Ir(pq) 2 (acac)) and other organic metal iridium complexes with a pyridine skeleton, bis(2,4-diphenyl-1,3-oxazol-N,C 2' )Iridium(III)acetylacetonate (abbreviated as: Ir(dpo) 2 (acac)), bis{2-[4'-(perfluorophenyl)phenyl]pyridine-N,C 2' Iridium(III) acetylacetonate (abbreviation: Ir(p-PF-ph) 2 (acac)), bis(2-phenylbenzothiazole-N,C 2' )Iridium(III)acetylacetonate (abbreviated as: Ir(bt) 2 (acac)) and other organometallic iridium complexes, tris(acetylacetonate)(monophanate)terbium(III) (abbreviated as: Tb(acac) 3 Among the above metal complexes, organic metal iridium complexes having a pyrimidine skeleton are particularly preferred because of their excellent reliability and luminous efficiency.

[0301] In addition, examples of substances having a light emission peak in the yellow or red wavelength range include (diisobutyrylmethane)bis[4,6-bis(3-methylphenyl)pyrimidinyl]iridium(III) (abbreviation: Ir(5mdppm) 2(dibm)), bis[4,6-bis(3-methylphenyl)pyrimidinyl](dipivaloylmethanyl)iridium(III) (abbreviated as: Ir(5mdppm) 2 (dpm)), bis[4,6-di(naphthalene-1-yl)pyrimidinyl](dipivaloylmethano)iridium(III) (abbreviated as: Ir(d1npm) 2 (dpm)) and other organic metal iridium complexes with pyrimidine skeletons; (acetylacetonato)bis(2,3,5-triphenylpyrazine)iridium(III) (abbreviated as: Ir(tppr) 2 (acac)), bis(2,3,5-triphenylpyrazine)(dipivaloylmethano)iridium(III) (abbreviated as: Ir(tppr) 2 (dpm)), (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxaline]iridium(III) (abbreviated as: Ir(Fdpq) 2 (acac)) and other organic metal iridium complexes with pyrazine skeletons; tris(1-phenylisoquinoline-N,C 2’ )Iridium(III) (Abbreviation: Ir(piq) 3 ), bis(1-phenylisoquinoline-N,C 2’ )iridium(III) acetylacetonate (abbreviated as: Ir(piq) 2 (acac)) and other organometallic iridium complexes with a pyridine skeleton; platinum complexes such as 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum (II) (abbreviated as PtOEP); and tris(1,3-diphenyl-1,3-propanedione)(monophanate)europium(III) (abbreviated as Eu(DBM) 3 (Phen)), tris[1-(2-thenoyl)-3,3,3-trifluoroacetone](monophanate) europium(III) (abbreviated as: Eu(TTA) 3 Among the above metal complexes, organic metal iridium complexes with a pyrimidine skeleton are particularly preferred because of their excellent reliability and luminous efficiency. In addition, organic metal iridium complexes with a pyrazine skeleton can provide red luminescence with good chromaticity.

[0302] As the luminescent material included in the luminescent layer 130, a material capable of converting triplet excitation energy into luminescence can be used. As the material capable of converting triplet excitation energy into luminescence, in addition to phosphorescent compounds, thermally activated delayed fluorescence (TADF) materials can be cited. Therefore, the description of phosphorescent compounds can be regarded as the description of thermally activated delayed fluorescence materials. Note that thermally activated delayed fluorescence materials refer to materials in which the difference between the triplet excitation energy level and the singlet excitation energy level is small and which has the function of converting energy from the triplet excited state to the singlet excited state by anti-intersystem crossing. Therefore, the triplet excited state can be upconverted (upconversion) to the singlet excited state (anti-intersystem crossing) by tiny thermal energy and luminescence (fluorescence) from the singlet excited state can be efficiently presented. In addition, the conditions for efficiently obtaining thermally activated delayed fluorescence are as follows: the energy difference between the triplet excited state energy level and the singlet excited state emission energy level is greater than 0 eV and is less than 0.2 eV, preferably greater than 0 eV and less than 0.1 eV.

[0303] When the thermally activated delayed fluorescent material is composed of one material, for example, the following materials can be used.

[0304] First, fullerene or its derivatives, acridine derivatives such as protoflavin, eosin, etc. can be cited. In addition, metal-containing porphyrins containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In) or palladium (Pd) can be cited. As the metal-containing porphyrin, for example, protoporphyrin-tin fluoride complex (SnF 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)), protoporphyrin-tin fluoride complex (SnF 2 (Etio I)), octaethylporphyrin-platinum chloride complex (PtCl 2 OEP) etc.

[0305] In addition, as a thermally activated delayed fluorescent material composed of a single material, a heterocyclic compound having a π-electron-rich aromatic heterocycle and a π-electron-deficient aromatic heterocycle can also be used. Specifically, 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazole-11-yl)-1,3,5-triazine (abbreviated as: PIC-TRZ), 2-{4-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviated as: PCCzPTzn), 2-[4-(10H-phenoxazine-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviated as: PXZ-TRZ), 3-[4-(5-phenyl-5,10-dihydrophenazine-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviation: PPZ-3TPT), 3-(9,9-dimethyl-9H-acridin-10-yl)-9H-oxanthene-9-one (abbreviation: ACRXTN), bis[4-(9,9-dimethyl-9,10-dihydroacridinium)phenyl]sulfone (abbreviation: DMAC-DPS), 10-phenyl-10H,10'H-spiro[acridin-9,9'-anthracenes]-10'-one (abbreviation: ACRSA), etc. This heterocyclic compound has a π-electron-rich aromatic heterocycle and a π-electron-deficient aromatic heterocycle, and therefore has high electron transport properties and hole transport properties, so it is preferred. In particular, among the skeletons having π-electron-deficient aromatic heterocycles, diazine skeletons (pyrimidine skeletons, pyrazine skeletons, pyridazine skeletons) or triazine skeletons are stable and have good reliability, so they are preferred. In addition, among the skeletons having π-electron-rich aromatic heterocycles, acridine skeletons, phenoxazine skeletons, thiophene skeletons, furan skeletons and pyrrole skeletons are stable and have good reliability, so it is preferred to have any one or more selected from these skeletons. As the pyrrole skeleton, it is particularly preferred to use an indole skeleton, a carbazole skeleton and a 3-(9-phenyl-9H-carbazole-3-yl)-9H-carbazole skeleton. In addition, in substances in which π-electron-rich aromatic heterocycles and π-electron-deficient aromatic heterocycles are directly bonded, the donor property of the π-electron-rich aromatic heterocycle and the acceptor property of the π-electron-deficient aromatic heterocycle are both strong, and the difference between the singlet excitation energy level and the triplet excitation energy level becomes smaller, so it is particularly preferred.

[0306] The light-emitting layer 130 may also be formed of a plurality of layers of more than two layers. For example, in the case where the light-emitting layer 130 is formed by stacking the first light-emitting layer and the second light-emitting layer in sequence from the hole transport layer side, a substance having a hole transport property may be used as the main material of the first light-emitting layer, and a substance having an electron transport property may be used as the main material of the second light-emitting layer. In addition, the light-emitting materials contained in the first light-emitting layer and the second light-emitting layer may also be the same or different materials. In addition, the light-emitting materials contained in the first light-emitting layer and the second light-emitting layer may be materials having the function of emitting light of the same color or materials having the function of emitting light of different colors. By using light-emitting materials having the function of emitting light of different colors from each other as two light-emitting layers, multiple light emission can be obtained at the same time. In particular, it is preferred to select the light-emitting material for each light-emitting layer so that white light emission can be obtained by combining the light emitted by the two light-emitting layers.

[0307] Furthermore, the light-emitting layer 130 may contain materials other than the host material 131 and the guest material 132 .

[0308] The light emitting layer 130 may be formed by evaporation (including vacuum evaporation), inkjet, coating, gravure printing, etc. In addition to the above materials, inorganic compounds such as quantum dots or high molecular compounds (oligomers, dendrimers, polymers, etc.) may also be included.

[0309] Hole injection layer

[0310] The hole injection layer 111 has the function of lowering the injection barrier of holes from one of the pair of electrodes (electrode 101 or electrode 102) to promote hole injection, and is formed using, for example, transition metal oxides, phthalocyanine derivatives or aromatic amines. Examples of transition metal oxides include molybdenum oxides, vanadium oxides, ruthenium oxides, tungsten oxides, manganese oxides, etc. Examples of phthalocyanine derivatives include phthalocyanine or metal phthalocyanines. Examples of aromatic amines include benzidine derivatives or phenylenediamine derivatives. In addition, polymer compounds such as polythiophene or polyaniline may also be used, typically: poly (ethyldioxythiophene) / poly (styrene sulfonic acid) as self-doped polythiophene.

[0311] As the hole injection layer 111, a layer having a composite material composed of a hole transport material and a material having the property of receiving electrons from the hole transport material can be used. Alternatively, a stack of a layer containing a material having the property of receiving electrons and a layer containing a hole transport material can be used. In a steady state or in the presence of an electric field, charge transfer can be performed between these materials. As materials having the property of receiving electrons, organic acceptors such as quinone dimethane derivatives, tetrachlorobenzoquinone derivatives, and hexaazatriphenylene derivatives can be cited. Specifically, 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviated as: F 4 Compounds having electron withdrawing groups (halogen or cyano) such as chloranil, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviated as HAT-CN) can be used. In addition, transition metal oxides, such as oxides of metals of Groups 4 to 8, can also be used. Specifically, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, rhenium oxide, etc. can be used. Molybdenum oxide is particularly preferably used because it is stable in the atmosphere, has low hygroscopicity, and is easy to handle.

[0312] As the hole transport material, a material having a hole transport property higher than an electron transport property can be used, and preferably a material having a 1×10 -6 cm 2 Specifically, aromatic amines, carbazole derivatives, aromatic hydrocarbons, stilbene derivatives, and the like, which are hole transporting materials that can be used for the light-emitting layer 130, can be used. The hole transporting materials may be polymer compounds.

[0313] Hole transport layer

[0314] The hole transport layer 112 is a layer containing a hole transport material, and the hole transport material exemplified as the material of the hole injection layer 111 can be used. The hole transport layer 112 has a function of transporting holes injected into the hole injection layer 111 to the light-emitting layer 130, and therefore preferably has a HOMO level that is the same as or close to the HOMO level of the hole injection layer 111.

[0315] In addition, it is preferred to use a 1×10 -6 cm 2 / Vs or more. However, as long as the hole transport property is higher than the electron transport property, a substance other than the above substances can be used. In addition, the layer including the substance with high hole transport property is not limited to a single layer, and two or more layers composed of the above substances can be stacked.

[0316] Electron Transport Layer

[0317] The electron transport layer 118 has a function of transporting electrons injected from the other of the pair of electrodes (electrode 101 or electrode 102) through the electron injection layer 119 to the light-emitting layer 130. As the electron transport material, a material having a higher electron transport property than a hole transport property can be used, and preferably a material having a 1×10 -6 cm 2 / Vs or more of the electron mobility. As the compound that easily accepts electrons (material with electron transport properties), π-electron-deficient heteroaromatic compounds such as nitrogen-containing heteroaromatic compounds or metal complexes can be used. Specifically, metal complexes including quinoline ligands, benzoquinoline ligands, oxazole ligands or thiazole ligands listed as electron transport materials that can be used for the light-emitting layer 130 can be cited. In addition, oxadiazole derivatives, triazole derivatives, benzimidazole derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, phenanthroline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, triazine derivatives, etc. can also be cited. In addition, it is preferably a material with 1×10 -6 cm 2 / Vs or higher. Any substance other than the above substances may be used as long as the electron transport property is higher than the hole transport property. In addition, the electron transport layer 118 is not limited to a single layer, and two or more layers composed of the above substances may be stacked.

[0318] In addition, a layer for controlling the movement of electron carriers may be provided between the electron transport layer 118 and the light-emitting layer 130. This layer is a layer in which a small amount of a substance with high electron capture property is added to the above-mentioned material with high electron transport property, and the balance of carriers can be adjusted by suppressing the movement of electron carriers. This structure has a great effect on suppressing problems caused by electrons passing through the light-emitting layer (such as a decrease in the life of the element).

[0319] 《Electron injection layer》

[0320] The electron injection layer 119 has the function of lowering the injection barrier of electrons from the electrode 102 and promoting electron injection. For example, a Group 1 metal, a Group 2 metal, or their oxides, halides, carbonates, etc. can be used. In addition, a composite material of the above-mentioned electron transport material and a material having the property of supplying electrons to the electron transport material can also be used. As materials having electron-donating properties, Group 1 metals, Group 2 metals, or their oxides, etc. can be cited. Specifically, lithium fluoride (LiF), sodium fluoride (NaF), cesium fluoride (CsF), calcium fluoride (CaF 2 ) and lithium oxide (LiO x ) or other alkali metals, alkaline earth metals, or compounds of these metals. In addition, erbium fluoride (ErF 3) and other rare earth metal compounds. In addition, an electron salt may be used for the electron injection layer 119. As the electron salt, for example, a substance in which electrons are added to a mixed oxide of calcium and aluminum at a high concentration may be cited. In addition, a substance that can be used for the electron transport layer 118 may be used for the electron injection layer 119.

[0321] In addition, a composite material formed by mixing an organic compound with an electron donor (donor) can also be used for the electron injection layer 119. This composite material has excellent electron injection and electron transport properties because electrons are generated in the organic compound by the electron donor. In this case, the organic compound is preferably a material with excellent performance in transporting the generated electrons. Specifically, for example, the substances (metal complexes, heteroaromatic compounds, etc.) constituting the electron transport layer 118 as described above can be used. As an electron donor, any substance that exhibits electron donating properties to organic compounds can be used. Specifically, alkali metals, alkaline earth metals and rare earth metals are preferably used, and lithium, sodium, cesium, magnesium, calcium, erbium, ytterbium, etc. can be cited. In addition, alkali metal oxides or alkaline earth metal oxides are preferably used, and lithium oxide, calcium oxide, barium oxide, etc. can be cited. In addition, Lewis bases such as magnesium oxide can also be used. In addition, organic compounds such as tetrathiafulvalene (abbreviated as: TTF) can also be used.

[0322] In addition, the above-mentioned light-emitting layer, hole injection layer, hole transport layer, electron transport layer and electron injection layer can be formed by evaporation (including vacuum evaporation), inkjet, coating, gravure printing and other methods. In addition, as the above-mentioned light-emitting layer, hole injection layer, hole transport layer, electron transport layer and electron injection layer, in addition to the above-mentioned materials, inorganic compounds such as quantum dots or high molecular compounds (oligomers, dendrimers, polymers, etc.) can also be used.

[0323] As quantum dots, colloidal quantum dots, alloy quantum dots, core-shell quantum dots, core-type quantum dots, etc. can be used. In addition, quantum dots containing element groups of Group 2 and Group 16, Group 13 and Group 15, Group 13 and Group 17, Group 11 and Group 17, or Group 14 and Group 15 can also be used. Alternatively, quantum dots containing elements such as cadmium (Cd), selenium (Se), zinc (Zn), sulfur (S), phosphorus (P), indium (In), tellurium (Te), lead (Pb), gallium (Ga), arsenic (As), and aluminum (Al) can be used.

[0324] A pair of electrodes

[0325] The electrode 101 and the electrode 102 are used as an anode or a cathode of the light-emitting element. The electrode 101 and the electrode 102 can be formed using a metal, an alloy, a conductive compound, a mixture or a stacked body thereof, or the like.

[0326] One of the electrode 101 and the electrode 102 is preferably formed using a conductive material having a function of reflecting light. As the conductive material, an alloy containing aluminum (Al) or Al can be cited. As an alloy containing Al, an alloy containing Al and L (L represents one or more of titanium (Ti), neodymium (Nd), nickel (Ni) and lanthanum (La)) can be cited, for example, an alloy containing Al and Ti or an alloy containing Al, Ni and La. Aluminum has low resistivity and high light reflectivity. In addition, since aluminum is contained in large quantities in the earth's crust and is not expensive, the use of aluminum can reduce the manufacturing cost of the light-emitting element. In addition, silver (Ag), alloys containing Ag, N (N represents one or more of yttrium (Y), Nd, magnesium (Mg), ytterbium (Yb), Al, Ti, gallium (Ga), zinc (Zn), indium (In), tungsten (W), manganese (Mn), tin (Sn), iron (Fe), Ni, copper (Cu), palladium (Pd), iridium (Ir) and gold (Au) can also be used. As alloys containing silver, for example, the following alloys can be cited: alloys containing silver, palladium and copper; alloys containing silver and copper; alloys containing silver and magnesium; alloys containing silver and nickel; alloys containing silver and gold; and alloys containing silver and ytterbium, etc. In addition to the above materials, transition metals such as tungsten, chromium (Cr), molybdenum (Mo), copper and titanium can be used.

[0327] In addition, light obtained from the light-emitting layer is extracted through one or both of the electrode 101 and the electrode 102. Therefore, at least one of the electrode 101 and the electrode 102 is preferably formed using a conductive material having a function of transmitting light. Examples of the conductive material include a material having a visible light transmittance of 40% or more and 100% or less, preferably 60% or more and 100% or less, and a resistivity of 1×10 -2 Conductive materials with a resistance of Ω·cm or less.

[0328] In addition, the electrodes 101 and 102 are preferably formed of a conductive material having a function of transmitting light and a function of reflecting light. Examples of the conductive material include a material having a reflectivity of visible light of 20% or more and 80% or less, preferably 40% or more and 70% or less, and a resistivity of 1×10 -2Ω·cm or less conductive material. For example, one or more conductive metals, alloys, and conductive compounds can be used. Specifically, metal oxides such as indium tin oxide (Indium Tin Oxide, hereinafter referred to as ITO), indium tin oxide containing silicon or silicon oxide (abbreviated as: ITSO), indium oxide-zinc oxide (Indium Zinc Oxide), indium oxide-tin oxide containing titanium, indium-titanium oxide, indium oxide containing tungsten oxide and zinc oxide. In addition, a metal film having a thickness that allows light to be transmitted (preferably a thickness of more than 1 nm and less than 30 nm) can be used. As the metal, for example, alloys of Ag, Ag and Al, Ag and Mg, Ag and Au, and Ag and Yb can be used.

[0329] Note that in this specification, as a material having a light-transmitting function, a material having a function of transmitting visible light and having conductivity may be used, such as the oxide conductor represented by ITO (Indium Tin Oxide), an oxide semiconductor, or an organic conductor containing organic matter. As an organic conductor containing organic matter, for example, a composite material containing a mixed organic compound and an electron donor (donor), a composite material containing a mixed organic compound and an electron acceptor (acceptor), etc. can be cited. Inorganic carbon materials such as graphene can also be used. In addition, the resistivity of the material is preferably 1×10 5 Ω·cm or less, more preferably 1×10 4 Ω·cm or less.

[0330] In addition, one or both of the electrode 101 and the electrode 102 may be formed by laminating a plurality of the above-mentioned materials.

[0331] In order to improve the light extraction efficiency, a material having a higher refractive index than the electrode can be formed in contact with the electrode having the function of transmitting light. As such a material, as long as it has the function of transmitting visible light, it can be a conductive material or a non-conductive material. For example, in addition to the above-mentioned oxide conductors, oxide semiconductors and organic substances can also be cited. As organic substances, for example, materials illustrated as light-emitting layers, hole injection layers, hole transport layers, electron transport layers, or electron injection layers can be cited. In addition, inorganic carbon materials or metal films having a thickness that allows light to be transmitted can also be used. In addition, multiple layers with a thickness of several nm to tens of nm can also be stacked.

[0332] When the electrode 101 or the electrode 102 is used as a cathode, it is preferable to use a material with a small work function (3.8 eV or less). For example, elements belonging to Group 1 or Group 2 of the periodic table (e.g., alkali metals such as lithium, sodium, and cesium, alkaline earth metals such as calcium or strontium, magnesium, etc.), alloys containing the above elements (e.g., Ag and Mg or Al and Li), rare earth metals such as europium (Eu) or Yb, alloys containing the above rare earth metals, alloys containing aluminum and silver, etc. can be used.

[0333] When the electrode 101 or the electrode 102 is used as an anode, it is preferable to use a material having a large work function (4.0 eV or more).

[0334] Electrodes 101 and 102 may also be formed of a stack of a conductive material having a function of reflecting light and a conductive material having a function of transmitting light. In this case, electrodes 101 and 102 have the function of adjusting the optical distance so that the desired light from each light-emitting layer resonates and enhances the light of its wavelength, so this is preferred.

[0335] As a film forming method of the electrode 101 and the electrode 102 , sputtering, vapor deposition, printing, coating, MBE (Molecular Beam Epitaxy) method, CVD method, pulse laser deposition method, ALD (Atomic Layer Deposition) method, etc. can be appropriately used.

[0336] Substrate

[0337] The light-emitting element of one embodiment of the present invention can be manufactured over a substrate made of glass, plastic, etc. The order of stacking layers on the substrate may be stacked sequentially from the electrode 101 side or from the electrode 102 side.

[0338] In addition, as a substrate capable of forming a light-emitting element of one embodiment of the present invention, for example, glass, quartz or plastic can be used. Alternatively, a flexible substrate can also be used. A flexible substrate is a substrate that can be bent, such as a plastic substrate made of polycarbonate or polyarylate. In addition, a film, an inorganic vapor-deposited film, etc. can be used. Note that other materials can be used as long as they serve as a support in the manufacturing process of the light-emitting element and the optical element. Alternatively, any material can be used as long as it has the function of protecting the light-emitting element and the optical element.

[0339] For example, in the present invention, various substrates can be used to form light-emitting elements. There is no particular restriction on the type of substrate. As examples of the substrate, for example, semiconductor substrates (for example, single crystal substrates or silicon substrates), SOI substrates, glass substrates, quartz substrates, plastic substrates, metal substrates, stainless steel substrates, substrates with stainless steel foils, tungsten substrates, substrates with tungsten foils, flexible substrates, laminated films, cellulose nanofibers (CNF) or paper or substrate films containing fibrous materials can be used. As examples of glass substrates, there are barium borosilicate glass, aluminum borosilicate glass, soda-lime glass, etc. As flexible substrates, laminated films, substrate films, etc., the following examples can be cited. For example, plastics represented by polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyether sulfone (PES), and polytetrafluoroethylene (PTFE) can be cited. Alternatively, as an example, resins such as acrylic resins can be cited. Alternatively, as an example, polypropylene, polyester, polyvinyl fluoride or polyvinyl chloride can be cited. Alternatively, polyamide, polyimide, aramid, epoxy resin, inorganic vapor-deposited film, paper, etc. can be cited as examples.

[0340] In addition, a flexible substrate may be used as a substrate, and a light-emitting element may be directly formed on the flexible substrate. Alternatively, a peeling layer may be provided between the substrate and the light-emitting element. The peeling layer may be used when a part or all of the light-emitting element is manufactured on the peeling layer, and then it is separated from the substrate and transferred to another substrate. In this case, the light-emitting element may also be transferred to a substrate with low heat resistance or a flexible substrate. In addition, as the above-mentioned peeling layer, for example, a laminated structure of an inorganic film of a tungsten film and a silicon oxide film or a structure in which a resin film such as polyimide is formed on a substrate may be used.

[0341] That is, a light-emitting element can also be formed using one substrate, and then the light-emitting element can be transferred to another substrate. As examples of substrates to which the light-emitting element is transferred, in addition to the above-mentioned substrates, there can be cited cellophane substrates, stone substrates, wood substrates, cloth substrates (including natural fibers (silk, cotton, linen), synthetic fibers (nylon, polyurethane, polyester) or regenerated fibers (acetate, cuprammonium fiber, rayon, regenerated polyester), etc.), leather substrates, rubber substrates, etc. By using these substrates, it is possible to manufacture light-emitting elements that are not easily damaged, light-emitting elements with high heat resistance, light-emitting elements that are lightweight, or light-emitting elements that are thin.

[0342] Alternatively, a field effect transistor (FET) may be formed over the substrate, and the light emitting element 150 may be formed on an electrode electrically connected to the FET. Thus, an active matrix display device in which driving of the light emitting element 150 is controlled by the FET can be manufactured.

[0343] In this embodiment, one mode of the present invention is described. In addition, in other embodiments, one mode of the present invention will be described. However, one mode of the present invention is not limited to this. That is, various modes of the invention are described in this embodiment and other embodiments, and thus one mode of the present invention is not limited to a specific mode. For example, although an example of applying one mode of the present invention to a light-emitting element is shown, one mode of the present invention is not limited to this. For example, depending on the situation or condition, one mode of the present invention may not be applied to a light-emitting element. In addition, although the following example is shown in one mode of the present invention, the example includes a first organic compound, a second organic compound, and a guest material having a function of converting triplet excitation energy into light emission, the LUMO energy level of the first organic compound is lower than the LUMO energy level of the second organic compound, and the HOMO energy level of the first organic compound is lower than the HOMO energy level of the second organic compound, but one mode of the present invention is not limited to this. In one mode of the present invention, depending on the situation or condition, for example, the LUMO energy level of the first organic compound may not be lower than the LUMO energy level of the second organic compound. In addition, the HOMO energy level of the first organic compound may not be lower than the HOMO energy level of the second organic compound. In addition, for example, an example in which the first organic compound and the second compound form an exciplex is shown in one embodiment of the present invention, but the present invention is not limited to this. In one embodiment of the present invention, depending on the situation or condition, for example, the first organic compound and the second organic compound may not form an exciplex. In addition, although an example is shown in one embodiment of the present invention in which the LUMO energy level of the guest material is higher than the LUMO energy level of the first organic compound and the HOMO energy level of the guest material is lower than the HOMO energy level of the second organic compound, the present invention is not limited to this. In one embodiment of the present invention, depending on the situation or condition, for example, the LUMO energy level of the guest material may not be higher than the LUMO energy level of the first organic compound. In addition, the HOMO energy level of the guest material may not be lower than the HOMO energy level of the second organic compound.

[0344] The structure described in this embodiment mode can be used in combination with the structures described in other embodiment modes as appropriate.

[0345] Implementation Method 2

[0346] In this embodiment, a novel compound that can be applied to the light-emitting element of one embodiment of the present invention is described.

[0347] The compound of one embodiment of the present invention is an iridium complex having a nitrogen-containing five-membered heterocyclic skeleton as its ligand, and the nitrogen-containing five-membered heterocyclic skeleton has at least a substituent containing a cyano group. Although the nitrogen-containing five-membered heterocyclic skeleton such as an imidazole skeleton or a triazole skeleton has a high triplet excitation energy level, the characteristic of receiving electrons is low compared with the nitrogen-containing six-membered heterocyclic skeleton. Thus, the LUMO energy level of the iridium complex having a nitrogen-containing five-membered heterocyclic skeleton as its ligand is higher, and the electron carrier is not easily injected. However, because the iridium complex of one embodiment of the present invention has at least a substituent containing a cyano group, the LUMO energy level and the HOMO energy level decrease due to the strong electron attraction of the cyano group. Therefore, by using the iridium complex for a light-emitting element, a light-emitting element with good luminous efficiency can be manufactured. In addition, since the iridium complex has a high triplet excitation energy level, by using the iridium complex for a light-emitting element, a light-emitting element with good luminous efficiency and blue color can be manufactured. In addition, since the iridium complex has high tolerance to repeated oxidation and reduction, by using the iridium complex for a light-emitting element, a light-emitting element with a long driving life can be manufactured. Thus, by using the iridium complex of one embodiment of the present invention in a light-emitting element, a high-performance light-emitting element having good light-emitting characteristics can be manufactured.

[0348] In addition, the compound of one embodiment of the present invention is an iridium complex having a ligand, in which an aryl group containing a cyano group is bonded to a nitrogen-containing five-membered heterocyclic skeleton. Because the ligand is easily synthesized with high purity, the degradation caused by impurities can be suppressed. In addition, from the viewpoint of the stability and reliability of the element characteristics, the number of carbon atoms of the aryl group containing a cyano group bonded to the nitrogen-containing five-membered heterocyclic skeleton is preferably 6 to 13. In this case, the iridium complex can be vacuum-deposited at a relatively low temperature, so it is not easy to cause degradation such as thermal decomposition during deposition.

[0349] In addition, because the nitrogen atom included in the nitrogen-containing five-membered heterocyclic skeleton is bonded to the iridium complex of the ligand of the cyano group through an arylene group, a high triplet excitation energy level can be maintained, so it can be applied to a light-emitting element that presents a high-energy light-emitting element such as blue light-emitting. In addition, a light-emitting element that presents a high-energy light-emitting element such as blue light-emitting and has a high luminous efficiency can be obtained compared to a light-emitting element that does not contain a cyano group. Furthermore, by bonding a cyano group to a specific position as described above, the light-emitting element also has the characteristics of presenting a high-energy light-emitting element such as blue light-emitting and having high reliability. In addition, the above-mentioned nitrogen-containing five-membered heterocyclic skeleton is preferably bonded to a cyano group through an arylene group such as a phenylene group.

[0350] In addition, when the number of carbon atoms of the arylene group is 6 to 13, the iridium complex becomes a compound with a relatively low molecular weight, thereby obtaining a compound suitable for vacuum evaporation (vacuum evaporation can be performed at a relatively low temperature). In addition, in general, when the molecular weight is low, the heat resistance after film formation is very low in many cases, but since the iridium complex has a plurality of ligands, it has the advantage of being able to ensure sufficient heat resistance even if the molecular weight of the ligand is low.

[0351] That is to say, the iridium complex not only has the above-mentioned easy evaporation property and electrochemical stability, but also has the characteristic of high triplet excitation energy level. Therefore, in the light-emitting element, the iridium complex is preferably used as the guest material of the light-emitting layer. In particular, the iridium complex is preferably used as the guest material of the blue light-emitting element.

[0352] <Iridium Complex Example 1>

[0353] The iridium complex is an iridium complex represented by the following general formula (G1).

[0354]

[0355] In the above general formula (G1), Ar 1 and Ar 2 Respectively independently represent a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. As the aryl group having 6 to 13 carbon atoms, specifically, phenyl, naphthyl, biphenyl and fluorenyl etc. can be mentioned. In the case where the aryl group has a substituent, as the substituent, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms can be selected. As the alkyl group having 1 to 6 carbon atoms, specifically, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl and n-hexyl etc. can be mentioned. As the cycloalkyl group having 3 to 6 carbon atoms, specifically, cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl etc. can be mentioned. As the aryl group having 6 to 13 carbon atoms, specifically, phenyl, naphthyl, biphenyl and fluorenyl etc. can be mentioned.

[0356] Q 1 and Q 2 Each independently represents N or CR, and R represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a halogenated alkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. 1 and Q 2At least one of them has CR. As an alkyl group having 1 to 6 carbon atoms, specifically, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl and n-hexyl can be mentioned. As a haloalkyl group having 1 to 6 carbon atoms, an alkyl group in which at least one hydrogen is replaced by an element of Group 17 (fluorine, chlorine, bromine, iodine, astatine) can be mentioned. As a haloalkyl group having 1 to 6 carbon atoms, fluorinated alkyl, chlorinated alkyl, brominated alkyl, iodinated alkyl and the like can be mentioned. Specifically, fluorinated methyl, chlorinated methyl, fluorinated ethyl, chlorinated ethyl and the like can be mentioned. The number and type of halogens contained in the haloalkyl group can be one or more. As an aryl group having 6 to 13 carbon atoms, specifically, phenyl, naphthyl, biphenyl and fluorenyl can be mentioned. The aryl group can also have a substituent, and the substituents can also be bonded to each other to form a ring. As the substituent, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an aryl group having 6 to 13 carbon atoms can be selected. As the alkyl group having 1 to 6 carbon atoms, specifically, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, and n-hexyl can be cited. As the cycloalkyl group having 3 to 6 carbon atoms, specifically, cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl can be cited. As the aryl group having 6 to 13 carbon atoms, specifically, phenyl, naphthyl, biphenyl, and fluorenyl can be cited.

[0357] Ar 1 and Ar 2 At least one of the aryl group represented by and the aryl group represented by R has a cyano group.

[0358] <Iridium Complex Example 2>

[0359] In addition, the iridium complex of one embodiment of the present invention is preferably an ortho-metal complex. The iridium complex is an iridium complex represented by the following general formula (G2).

[0360]

[0361] In the above general formula (G2), Ar 1Represents a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. As the aryl group having 6 to 13 carbon atoms, specifically, phenyl, naphthyl, biphenyl and fluorenyl etc. can be mentioned. In the case where the aryl group has a substituent, as the substituent, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms can be selected. As the alkyl group having 1 to 6 carbon atoms, specifically, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl and n-hexyl etc. can be mentioned. As the cycloalkyl group having 3 to 6 carbon atoms, specifically, cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl etc. can be mentioned. As the aryl group having 6 to 13 carbon atoms, specifically, phenyl, naphthyl, biphenyl and fluorenyl etc. can be mentioned.

[0362] R 1 To R 4 Each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, and a cyano group. As the alkyl group having 1 to 6 carbon atoms, specifically, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, and n-hexyl, etc. can be mentioned. As the cycloalkyl group having 3 to 6 carbon atoms, specifically, cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl, etc. can be mentioned. As the aryl group having 6 to 13 carbon atoms, specifically, phenyl, naphthyl, biphenyl, and fluorenyl, etc. can be mentioned. If R 1 To R 4 If all of them are hydrogen, it is advantageous in terms of ease of synthesis and raw material price.

[0363] Q 1 and Q 2 Each independently represents N or CR, and R represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a halogenated alkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. 1 and Q 2At least one of them has CR. As an alkyl group with 1 to 6 carbon atoms, specifically, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl and n-hexyl can be mentioned. As a haloalkyl group with 1 to 6 carbon atoms, an alkyl group such as fluorinated alkyl, chlorinated alkyl, brominated alkyl, iodinated alkyl, etc., which uses a 17th group element (fluorine, chlorine, bromine, iodine, astatine) to replace at least one hydrogen can be mentioned. Specifically, fluorinated methyl, chlorinated methyl, fluorinated ethyl, chlorinated ethyl, etc. can be mentioned. The number and type of halogens contained in the haloalkyl group can be one or more. As an aryl group with 6 to 13 carbon atoms, specifically, phenyl, naphthyl, biphenyl and fluorenyl can be mentioned. The aryl group can also have a substituent, and the substituent can also be bonded to each other to form a ring. As the substituent, an alkyl group with 1 to 6 carbon atoms, a cycloalkyl group with 3 to 6 carbon atoms, or an aryl group with 6 to 13 carbon atoms can be selected. As the alkyl group having 1 to 6 carbon atoms, specifically, there can be mentioned a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, and an n-hexyl group, etc. As the cycloalkyl group having 3 to 6 carbon atoms, specifically, there can be mentioned a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group, etc. As the aryl group having 6 to 13 carbon atoms, specifically, there can be mentioned a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group, etc.

[0364] In addition, Ar 1 and R 1 To R 4 The aryl group represented by R and the aryl group represented by R 1 To R 4 At least one of them has a cyano group.

[0365] <Iridium Complex Example 3>

[0366] In one embodiment of the iridium complex of the present invention, a 4H-triazole skeleton is provided as a ligand, so that a high triplet excitation energy level can be obtained, and thus the iridium complex is preferably used in a light-emitting element exhibiting high-energy light emission such as blue light emission. The iridium complex is an iridium complex represented by the following general formula (G3).

[0367]

[0368] In the above general formula (G3), Ar 1Represents a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. As the aryl group having 6 to 13 carbon atoms, specifically, phenyl, naphthyl, biphenyl and fluorenyl etc. can be mentioned. In the case where the aryl group has a substituent, as the substituent, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms can be selected. As the alkyl group having 1 to 6 carbon atoms, specifically, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl and n-hexyl etc. can be mentioned. As the cycloalkyl group having 3 to 6 carbon atoms, specifically, cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl etc. can be mentioned. As the aryl group having 6 to 13 carbon atoms, specifically, phenyl, naphthyl, biphenyl and fluorenyl etc. can be mentioned.

[0369] R 1 To R 4 Each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, and a cyano group. As the alkyl group having 1 to 6 carbon atoms, specifically, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, and n-hexyl, etc. can be mentioned. As the cycloalkyl group having 3 to 6 carbon atoms, specifically, cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl, etc. can be mentioned. As the aryl group having 6 to 13 carbon atoms, specifically, phenyl, naphthyl, biphenyl, and fluorenyl, etc. can be mentioned. If R 1 To R 4 If all of them are hydrogen, it is advantageous in terms of ease of synthesis and raw material price.

[0370] R 5Represents any one of hydrogen, alkyl having 1 to 6 carbon atoms, haloalkyl having 1 to 6 carbon atoms, and substituted or unsubstituted aryl having 6 to 13 carbon atoms. As alkyl having 1 to 6 carbon atoms, specifically, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl and n-hexyl etc. can be cited. As haloalkyl having 1 to 6 carbon atoms, alkyl such as fluorinated alkyl, chlorinated alkyl, brominated alkyl, iodinated alkyl etc., which use elements of Group 17 (fluorine, chlorine, bromine, iodine, astatine) to replace at least one hydrogen can be cited. Specifically, methyl fluoride, methyl chloride, ethyl fluoride, ethyl chloride etc. can be cited. The number and type of halogen contained in the haloalkyl can be one or more. As aryl having 6 to 13 carbon atoms, specifically, phenyl, naphthyl, biphenyl and fluorenyl etc. can be cited. The aryl can also have a substituent, and the substituent can also be bonded to each other to form a ring. As the substituent, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an aryl group having 6 to 13 carbon atoms can be selected. As the alkyl group having 1 to 6 carbon atoms, specifically, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, and n-hexyl can be cited. As the cycloalkyl group having 3 to 6 carbon atoms, specifically, cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl can be cited. As the aryl group having 6 to 13 carbon atoms, specifically, phenyl, naphthyl, biphenyl, and fluorenyl can be cited.

[0371] In addition, Ar 1 and R 1 To R 5 The aryl group and R 1 To R 4 At least one of them has a cyano group.

[0372] <Iridium Complex Example 4>

[0373] In one embodiment of the iridium complex of the present invention, the iridium complex has an imidazole skeleton as a ligand and can have a high triplet excitation energy level, so it can be applied to a light-emitting element that emits high energy such as blue light, and is therefore preferred. The above-mentioned iridium complex is an iridium complex represented by the following general formula (G4).

[0374]

[0375] In the above general formula (G4), Ar 1Represents a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. As the aryl group having 6 to 13 carbon atoms, specifically, phenyl, naphthyl, biphenyl and fluorenyl etc. can be mentioned. In the case where the aryl group has a substituent, as the substituent, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms can be selected. As the alkyl group having 1 to 6 carbon atoms, specifically, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl and n-hexyl etc. can be mentioned. As the cycloalkyl group having 3 to 6 carbon atoms, specifically, cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl etc. can be mentioned. As the aryl group having 6 to 13 carbon atoms, specifically, phenyl, naphthyl, biphenyl and fluorenyl etc. can be mentioned.

[0376] R 1 To R 4 Each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. As the alkyl group having 1 to 6 carbon atoms, specifically, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, and n-hexyl can be mentioned. As the cycloalkyl group having 3 to 6 carbon atoms, specifically, cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl can be mentioned. As the aryl group having 6 to 13 carbon atoms, specifically, phenyl, naphthyl, biphenyl, and fluorenyl can be mentioned. If R 1 To R 4 If all of them are hydrogen, it is advantageous in terms of ease of synthesis and raw material price.

[0377] R 5 and R 6Respectively independently represent any one of hydrogen, alkyl having 1 to 6 carbon atoms, haloalkyl having 1 to 6 carbon atoms, and substituted or unsubstituted aryl having 6 to 13 carbon atoms. As alkyl having 1 to 6 carbon atoms, specifically, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl and n-hexyl can be cited. As haloalkyl having 1 to 6 carbon atoms, alkyl such as fluorinated alkyl, chlorinated alkyl, brominated alkyl, iodinated alkyl, etc., which use elements of Group 17 (fluorine, chlorine, bromine, iodine, astatine) to replace at least one hydrogen can be cited. Specifically, methyl fluoride, methyl chloride, ethyl fluoride, ethyl chloride, etc. can be cited. The number and type of halogens contained in the haloalkyl can be one or more. As aryl having 6 to 13 carbon atoms, specifically, phenyl, naphthyl, biphenyl and fluorenyl can be cited. The aryl can also have a substituent, and the substituent can also be bonded to each other to form a ring. As the substituent, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an aryl group having 6 to 13 carbon atoms can be selected. As the alkyl group having 1 to 6 carbon atoms, specifically, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, and n-hexyl can be cited. As the cycloalkyl group having 3 to 6 carbon atoms, specifically, cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl can be cited. As the aryl group having 6 to 13 carbon atoms, specifically, phenyl, naphthyl, biphenyl, and fluorenyl can be cited.

[0378] In addition, Ar 1 and R 1 To R 6 The aryl group and R 1 To R 4 At least one of them has a cyano group.

[0379] <Iridium Complex Example 5>

[0380] In the iridium complex of one embodiment of the present invention, when the aryl group bonded to the nitrogen of the nitrogen-containing five-membered heterocyclic skeleton is a substituted or unsubstituted phenyl group, vacuum deposition can be performed at a relatively low temperature and has a high triplet excitation energy level, thereby being applicable to light-emitting elements exhibiting high-energy light emission such as blue light emission, and therefore being preferred. The above-mentioned iridium complex is an iridium complex represented by the following general formulas (G5) and (G6).

[0381]

[0382] In the above general formula (G5), R 7 and R 11 represents an alkyl group having 1 to 6 carbon atoms, R 7 and R 11The alkyl groups having 1 to 6 carbon atoms include, specifically, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, and n-hexyl.

[0383] R 8 To R 10 R and R are independently any of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and a substituted or unsubstituted phenyl group and a cyano group. Specifically, the alkyl group having 1 to 6 carbon atoms includes methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, and n-hexyl. Specifically, the cycloalkyl group having 3 to 6 carbon atoms includes cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl. 8 To R 10 At least one of them preferably has a cyano group.

[0384] R 1 To R 4 Each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. As the alkyl group having 1 to 6 carbon atoms, specifically, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, and n-hexyl can be mentioned. As the cycloalkyl group having 3 to 6 carbon atoms, specifically, cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl can be mentioned. As the aryl group having 6 to 13 carbon atoms, specifically, phenyl, naphthyl, biphenyl, and fluorenyl can be mentioned. If R 1 To R 4 If all of them are hydrogen, it is advantageous in terms of ease of synthesis and raw material price.

[0385] R 5Represents any one of hydrogen, alkyl having 1 to 6 carbon atoms, haloalkyl having 1 to 6 carbon atoms, and substituted or unsubstituted aryl having 6 to 13 carbon atoms. As alkyl having 1 to 6 carbon atoms, specifically, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl and n-hexyl etc. can be cited. As haloalkyl having 1 to 6 carbon atoms, alkyl such as fluorinated alkyl, chlorinated alkyl, brominated alkyl, iodinated alkyl etc., which use elements of Group 17 (fluorine, chlorine, bromine, iodine, astatine) to replace at least one hydrogen can be cited. Specifically, methyl fluoride, methyl chloride, ethyl fluoride, ethyl chloride etc. can be cited. The number and type of halogen contained in the haloalkyl can be one or more. As aryl having 6 to 13 carbon atoms, specifically, phenyl, naphthyl, biphenyl and fluorenyl etc. can be cited. The aryl can also have a substituent, and the substituent can also be bonded to each other to form a ring. As the substituent, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an aryl group having 6 to 13 carbon atoms can be selected. As the alkyl group having 1 to 6 carbon atoms, specifically, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, and n-hexyl can be cited. As the cycloalkyl group having 3 to 6 carbon atoms, specifically, cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl can be cited. As the aryl group having 6 to 13 carbon atoms, specifically, phenyl, naphthyl, biphenyl, and fluorenyl can be cited.

[0386]

[0387] In the above general formula (G6), R 7 and R 11 represents an alkyl group having 1 to 6 carbon atoms, R 7 and R 11 The alkyl groups having 1 to 6 carbon atoms include, specifically, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, and n-hexyl.

[0388] R 8 To R 10 R and R are independently any of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and a substituted or unsubstituted phenyl group and a cyano group. Specifically, the alkyl group having 1 to 6 carbon atoms includes methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, and n-hexyl. Specifically, the cycloalkyl group having 3 to 6 carbon atoms includes cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl. 8 To R 10 At least one of them preferably has a cyano group.

[0389] R 1 To R 4Each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. As the alkyl group having 1 to 6 carbon atoms, specifically, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, and n-hexyl can be mentioned. As the cycloalkyl group having 3 to 6 carbon atoms, specifically, cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl can be mentioned. As the aryl group having 6 to 13 carbon atoms, specifically, phenyl, naphthyl, biphenyl, and fluorenyl can be mentioned. If R 1 To R 4 If all of them are hydrogen, it is advantageous in terms of ease of synthesis and raw material price.

[0390] R 5 and R 6 Respectively independently represent any one of hydrogen, alkyl having 1 to 6 carbon atoms, haloalkyl having 1 to 6 carbon atoms, and substituted or unsubstituted aryl having 6 to 13 carbon atoms. As alkyl having 1 to 6 carbon atoms, specifically, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl and n-hexyl can be cited. As haloalkyl having 1 to 6 carbon atoms, alkyl such as fluorinated alkyl, chlorinated alkyl, brominated alkyl, iodinated alkyl, etc., which use elements of Group 17 (fluorine, chlorine, bromine, iodine, astatine) to replace at least one hydrogen can be cited. Specifically, methyl fluoride, methyl chloride, ethyl fluoride, ethyl chloride, etc. can be cited. The number and type of halogens contained in the haloalkyl can be one or more. As aryl having 6 to 13 carbon atoms, specifically, phenyl, naphthyl, biphenyl and fluorenyl can be cited. The aryl can also have a substituent, and the substituent can also be bonded to each other to form a ring. As the substituent, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an aryl group having 6 to 13 carbon atoms can be selected. As the alkyl group having 1 to 6 carbon atoms, specifically, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, and n-hexyl can be cited. As the cycloalkyl group having 3 to 6 carbon atoms, specifically, cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl can be cited. As the aryl group having 6 to 13 carbon atoms, specifically, phenyl, naphthyl, biphenyl, and fluorenyl can be cited.

[0391] <Iridium Complex Example 6>

[0392] In one embodiment of the iridium complex of the present invention, a 1H-triazole skeleton is provided as a ligand, so that a high triplet excitation energy level can be obtained, and thus the iridium complex can be applied to a light-emitting element exhibiting high-energy light emission such as blue light emission, and thus is preferred. The above-mentioned iridium complex is an iridium complex represented by the following general formulas (G7) and (G8).

[0393]

[0394] In the above general formula (G7), Ar 1 Represents a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. As the aryl group having 6 to 13 carbon atoms, specifically, phenyl, naphthyl, biphenyl and fluorenyl etc. can be mentioned. In the case where the aryl group has a substituent, as the substituent, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms can be selected. As the alkyl group having 1 to 6 carbon atoms, specifically, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl and n-hexyl etc. can be mentioned. As the cycloalkyl group having 3 to 6 carbon atoms, specifically, cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl etc. can be mentioned. As the aryl group having 6 to 13 carbon atoms, specifically, phenyl, naphthyl, biphenyl and fluorenyl etc. can be mentioned.

[0395] R 1 To R 4 Each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. As the alkyl group having 1 to 6 carbon atoms, specifically, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, and n-hexyl can be mentioned. As the cycloalkyl group having 3 to 6 carbon atoms, specifically, cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl can be mentioned. As the aryl group having 6 to 13 carbon atoms, specifically, phenyl, naphthyl, biphenyl, and fluorenyl can be mentioned. If R 1 To R 4 If all of them are hydrogen, it is advantageous in terms of ease of synthesis and raw material price.

[0396] R 6Represents any one of hydrogen, alkyl having 1 to 6 carbon atoms, haloalkyl having 1 to 6 carbon atoms, and substituted or unsubstituted aryl having 6 to 13 carbon atoms. As alkyl having 1 to 6 carbon atoms, specifically, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl and n-hexyl etc. can be cited. As haloalkyl having 1 to 6 carbon atoms, alkyl such as fluorinated alkyl, chlorinated alkyl, brominated alkyl, iodinated alkyl etc., which use elements of Group 17 (fluorine, chlorine, bromine, iodine, astatine) to replace at least one hydrogen can be cited. Specifically, methyl fluoride, methyl chloride, ethyl fluoride, ethyl chloride etc. can be cited. The number and type of halogen contained in the haloalkyl can be one or more. As aryl having 6 to 13 carbon atoms, specifically, phenyl, naphthyl, biphenyl and fluorenyl etc. can be cited. The aryl can also have a substituent, and the substituent can also be bonded to each other to form a ring. As the substituent, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an aryl group having 6 to 13 carbon atoms can be selected. As the alkyl group having 1 to 6 carbon atoms, specifically, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, and n-hexyl can be cited. As the cycloalkyl group having 3 to 6 carbon atoms, specifically, cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl can be cited. As the aryl group having 6 to 13 carbon atoms, specifically, phenyl, naphthyl, biphenyl, and fluorenyl can be cited.

[0397] In addition, Ar 1 , R 1 To R 4 and R 6 The aryl group and R 1 To R 4 At least one of them has a cyano group.

[0398]

[0399] In the above general formula (G8), R 7 and R 11 represents an alkyl group having 1 to 6 carbon atoms, R 7 and R 11 The alkyl groups having 1 to 6 carbon atoms include, specifically, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, and n-hexyl.

[0400] R 8 To R 10R and R are independently any of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and a substituted or unsubstituted phenyl group and a cyano group. Specifically, the alkyl group having 1 to 6 carbon atoms includes methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, and n-hexyl. Specifically, the cycloalkyl group having 3 to 6 carbon atoms includes cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl. 8 To R 10 At least one of them preferably has a cyano group.

[0401] R 1 To R 4 Each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. As the alkyl group having 1 to 6 carbon atoms, specifically, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, and n-hexyl can be mentioned. As the cycloalkyl group having 3 to 6 carbon atoms, specifically, cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl can be mentioned. As the aryl group having 6 to 13 carbon atoms, specifically, phenyl, naphthyl, biphenyl, and fluorenyl can be mentioned. If R 1 To R 4 If all of them are hydrogen, it is advantageous in terms of ease of synthesis and raw material price.

[0402] R 6Represents any one of hydrogen, alkyl having 1 to 6 carbon atoms, haloalkyl having 1 to 6 carbon atoms, and substituted or unsubstituted aryl having 6 to 13 carbon atoms. As alkyl having 1 to 6 carbon atoms, specifically, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl and n-hexyl etc. can be cited. As haloalkyl having 1 to 6 carbon atoms, alkyl such as fluorinated alkyl, chlorinated alkyl, brominated alkyl, iodinated alkyl etc., which use elements of Group 17 (fluorine, chlorine, bromine, iodine, astatine) to replace at least one hydrogen can be cited. Specifically, methyl fluoride, methyl chloride, ethyl fluoride, ethyl chloride etc. can be cited. The number and type of halogen contained in the haloalkyl can be one or more. As aryl having 6 to 13 carbon atoms, specifically, phenyl, naphthyl, biphenyl and fluorenyl etc. can be cited. The aryl can also have a substituent, and the substituent can also be bonded to each other to form a ring. As the substituent, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an aryl group having 6 to 13 carbon atoms can be selected. As the alkyl group having 1 to 6 carbon atoms, specifically, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, and n-hexyl can be cited. As the cycloalkyl group having 3 to 6 carbon atoms, specifically, cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl can be cited. As the aryl group having 6 to 13 carbon atoms, specifically, phenyl, naphthyl, biphenyl, and fluorenyl can be cited.

[0403] <Examples of Substituents>

[0404] As R of the above general formulae (G2) to (G8) 1 To R 4 As the alkyl group and the aryl group represented by the following structural formulas (R-1) to (R-29), for example, the groups that can be used as the alkyl group and the aryl group are not limited to these.

[0405]

[0406] In addition, as the compound represented by Ar in the general formulae (G1) to (G4) and (G7), 1 The aryl group represented by Ar in the general formula (G1) 2 The aromatic group represented by the above-mentioned structural formulas (R-12) to (R-29) can be used. 1 and Ar 2 The base is not limited to this.

[0407] In addition, as R of the general formula (G5), (G6) and (G8) 7 and R 11 As the alkyl group represented by, for example, the groups represented by the above-mentioned structural formulas (R-1) to (R-10) can be used. Note that the groups that can be used as the alkyl group are not limited to these.

[0408] In addition, as R of the general formula (G5), (G6) and (G8) 8 To R 10 As the alkyl group or the substituted or unsubstituted phenyl group, for example, the groups represented by the above-mentioned structural formulas (R-1) to (R-22) can be used. Note that the groups that can be used as the alkyl group or the phenyl group are not limited thereto.

[0409] In addition, as R in the above general formulas (G3) to (G6), 5 and R of the general formula (G4), (G6) to (G8) 6 The alkyl group, aryl group or halogenated alkyl group represented by the above-mentioned structural formulas (R-1) to (R-29) and the following structural formulas (R-30) to (R-37) can be used. Note that the groups that can be used as the alkyl group, aryl group or halogenated alkyl group are not limited thereto.

[0410]

[0411] <Specific Examples of Iridium Complexes>

[0412] Specific structures of the iridium complexes represented by the above general formulae (G1) to (G8) include compounds represented by the following structural formulae (100) to (134). Note that the iridium complexes represented by the general formulae (G1) to (G8) are not limited to the following examples.

[0413]

[0414]

[0415]

[0416]

[0417]

[0418]

[0419] As described above, since the iridium complex of one embodiment of the present invention has a lower HOMO energy level and LUMO energy level, it is suitable for a guest material of a light-emitting element. Therefore, a light-emitting element with good luminous efficiency can be manufactured. In addition, since the iridium complex of one embodiment of the present invention has a high triplet excitation energy level, it is particularly suitable for a guest material of a blue light-emitting element. Therefore, a blue light-emitting element with good luminous efficiency can be manufactured. In addition, since the iridium complex of one embodiment of the present invention has a high resistance to repeated oxidation and reduction, a light-emitting element with a long driving life can be manufactured by using the iridium complex for a light-emitting element. As described above, the iridium complex of one embodiment of the present invention is a material suitable for a light-emitting element.

[0420] The iridium complex of one embodiment of the present invention can be deposited by a method such as vapor deposition (including vacuum vapor deposition), inkjet, coating, or gravure printing.

[0421] The compound described in this embodiment mode can be used in combination with the structure described in other embodiments mode as appropriate.

[0422] Implementation 3

[0423] In this embodiment, an example of a synthetic method of an iridium complex having a structure represented by the general formula (G1), (G3), (G4) and (G7) is described. Various reactions can be used as the synthetic method of the iridium complex. For example, by carrying out the synthesis reaction shown below, an iridium complex represented by the general formula (G1), (G3), (G4) and (G7) can be synthesized. Note that the synthetic method of the iridium complex as one embodiment of the present invention is not limited to the following synthetic method.

[0424] <Method for synthesizing iridium complex represented by general formula (G1)>

[0425] An example of a method for synthesizing an iridium complex having a structure represented by the general formula (G1) will be described.

[0426] As shown in the following synthesis scheme (a), a nitrogen-containing five-membered ring derivative represented by the general formula (G0) is mixed with an iridium metal compound containing a halogen (iridium chloride hydrate, ammonium hexachloroiridate, etc.) or an iridium organometallic complex compound (acetylacetonate complex, diethyl sulfide complex, etc.) and then heated, thereby obtaining an iridium complex having a structure represented by the general formula (G1). In addition, the heating step can also be performed after dissolving the nitrogen-containing five-membered ring derivative represented by the general formula (G0) and the iridium metal compound containing a halogen or the iridium organometallic complex compound in an alcohol solvent (glycerol, ethylene glycol, 2-methoxyethanol, 2-ethoxyethanol, etc.).

[0427]

[0428] In the synthetic scheme (a), Ar 1 and Ar 2 Each independently represents a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. 1 and Q 2 Each independently represents N or CR, and R represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a halogenated alkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. 1 and Q 2 At least one of them has CR. 1 and Ar 2 At least one of the aryl group represented by and the aryl group represented by R has a cyano group.

[0429] Note that the method for synthesizing an iridium complex having a structure represented by the general formula (G1) is not limited to the synthesis scheme (a). For example, as an example of another synthesis method, as shown in the following synthesis scheme (a'), by making a iridium complex having a structure represented by Ar 3 and Ar 4 An iridium complex having a structure represented by the general formula (G1) can be obtained by reacting an iridium complex having at least one ligand substituted with a halogen group in the aryl group represented by the formula with an aryl boronic acid compound substituted with a cyano group or copper cyanide. Alternatively, an iridium complex containing a halogenated aryl group substituted with Ar as a ligand can be reacted with an iridium complex having a structure represented by the general formula (G1). 3 and Ar 4 A compound in which at least one of the aryl groups represented is boronic acid, boronic ester or cyclic triol borate.

[0430]

[0431] In the above synthesis scheme (a'), Ar 1 and Ar 2 Each independently represents a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. 1 and Q 2 Each independently represents N or CR, and R represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a halogenated alkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. 1 and Q 2 At least one of them has CR. 1 and Ar 2 At least one of the aryl group represented by and the aryl group represented by R has a cyano group.

[0432] As described above, the iridium complex of the general formula (G1) can be synthesized.

[0433] <Method for synthesizing iridium complex represented by general formula (G3)>

[0434] Next, an example of a method for synthesizing an iridium complex having a structure represented by the general formula (G3) is described.

[0435] 《Synthesis method of 1,2,4-triazole derivatives》

[0436] First, an example of a method for synthesizing a 1,2,4-triazole derivative represented by the following general formula (G0-X1) is described.

[0437]

[0438] In the general formula (G0-X1), Ar 1 represents a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. 1 To R 4 R each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, and a cyano group. 5 represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a halogenated alkyl group having 1 to 6 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. 1 To R 4 and Ar 1 and R 1 To R 5 At least one of the aryl groups represented has a cyano group.

[0439] As shown in the following synthesis scheme (b), a 1,2,4-triazole derivative represented by the general formula (G0-X1) can be obtained by reacting a hydrazide compound (A1) with a thioether compound or an N-substituted thioamide compound (A2). 1 represents a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. 1 To R 4 R each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. 5 represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a halogenated alkyl group having 1 to 6 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. 1 and R 1 To R 5 The aryl group and R 1 To R 4 At least one of them has a cyano group.

[0440]

[0441] Note that the synthesis method of the 1,2,4-triazole derivative represented by the general formula (G0-X1) is not limited to the synthesis scheme (b). For example, as an example of another synthesis method, there is also a method of reacting a dihydrazide compound (A1') with a primary amine compound (A2') as shown in the following synthesis scheme (b'). In the synthesis scheme (b'), Ar 1 represents a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. 1 To R 4 R each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, and a cyano group. 5 represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a halogenated alkyl group having 1 to 6 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. 1 and R 1 To R 5 The aryl group and R 1 To R 4 At least one of them has a cyano group.

[0442]

[0443] As described above, the 1,2,4-triazole derivative represented by the general formula (G0-X1) can be synthesized by a simple synthetic scheme.

[0444] Then, by the same synthesis method as the above-mentioned synthesis scheme (a), a 1,2,4-triazole derivative represented by the general formula (G0-X1) is mixed with an iridium metal compound containing a halogen (iridium chloride hydrate, ammonium hexachloroiridate, etc.) or an iridium organometallic complex compound (acetylacetonate complex, diethyl sulfide complex, etc.) and then heated, thereby obtaining an iridium complex having a structure represented by the general formula (G3).

[0445] As described above, the iridium complex of the general formula (G3) can be synthesized.

[0446] In one embodiment of the present invention, in order to obtain an iridium complex, the iridium complex is an ortho-metal complex using a 1,2,4-triazole derivative represented by the general formula (G3) as a ligand, and the 5-position (i.e., R 5 ) to introduce a substituent. In particular, when R 5 When any one of an alkyl group having 1 to 6 carbon atoms, a halogenated alkyl group having 1 to 6 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms is used, 5The use of hydrogen is preferred because the yield in the synthesis scheme (a) can be improved compared to the case of using hydrogen.

[0447] <Method for synthesizing iridium complex represented by general formula (G4)>

[0448] Next, an example of a method for synthesizing an iridium complex having a structure represented by the general formula (G4) is described.

[0449] 《Synthesis of Imidazole Derivatives》

[0450] First, an example of a method for synthesizing an imidazole derivative represented by the following general formula (G0-X2) will be described.

[0451]

[0452] In the general formula (G0-X2), Ar 1 represents a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. 1 To R 4 Each independently represents hydrogen, an alkyl group having 1 to 6 carbon atoms, or a cycloalkyl group having 3 to 6 carbon atoms. 1 To R 4 and Ar 1 and R 1 To R 4 At least one of the aryl groups represented has a cyano group.

[0453] As shown in the following synthesis scheme (c), the N-(2-chloroethyl)benzamide compound (B1) is first reacted with a chlorinating agent and then reacted with a primary amine compound (B2) to obtain an intermediate (B3). Examples of the chlorinating agent include phosphorus pentachloride or phosphorus oxychloride. Furthermore, the intermediate (B3) is reacted with a dehydrogenating agent to obtain an imidazole derivative represented by the general formula (G0-X2). Examples of the dehydrogenating agent include potassium permanganate or a quinone derivative. In the synthesis scheme (c), Ar 1 represents a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. 1 To R 4 and each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. 1 and R 1 To R 4 The aryl group and R 1 To R 4 At least one of them has a cyano group.

[0454]

[0455] Note that the method for synthesizing the imidazole derivative represented by the general formula (G0-X2) is not limited to the synthesis scheme (c). For example, as an example of another synthesis method, as shown in the following synthesis scheme (c'), there is also a method in which a thioether compound or an imino chloride compound (B1') is reacted with aminoacetaldehyde dimethyl acetal and then an inorganic acid is added thereto to react. Examples of the inorganic acid include phosphoric acid and hydrochloric acid. In the synthesis scheme (c'), Ar 1 represents a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. 1 To R 4 and each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. 1 and R 1 To R 4 The aryl group and R 1 To R 4 At least one of them has a cyano group.

[0456]

[0457] Next, an example of a method for synthesizing an imidazole derivative represented by the following general formula (G0-X3) is described.

[0458]

[0459] In the general formula (G0-X3), Ar 1 represents a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. 1 To R 4 R each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. 5 and R 6 and each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a haloalkyl group having 1 to 6 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. 1 and R 1 To R 6 The aryl group and R 1 To R 6 At least one of them has a cyano group.

[0460] As shown in the following synthesis scheme (c"), there is also a method of mixing a β-diketone compound (B1"), a primary amine compound (B2), and a benzaldehyde compound (B3") to react. In the synthesis scheme (c"), Ar 1 represents a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. 1 To R 4 R each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. 5 and R 6 and each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a haloalkyl group having 1 to 6 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. 1 and R 1 To R 4 The aryl group and R 1 To R 4 At least one of them has a cyano group.

[0461]

[0462] As described above, the imidazole derivative represented by the general formula (G0-X3) can be synthesized by a simple synthetic scheme.

[0463] Then, by the same synthesis method as the above-mentioned synthesis scheme (a), the imidazole derivative represented by the general formula (G0-X3) is mixed with an iridium metal compound containing a halogen (iridium chloride hydrate, ammonium hexachloroiridate, etc.) or an iridium organometallic complex compound (acetylacetonate complex, diethyl sulfide complex, etc.) and then heated, thereby obtaining an iridium complex having a structure represented by the general formula (G4).

[0464] As described above, the iridium complex of the general formula (G4) can be synthesized.

[0465] <Method for synthesizing iridium complex represented by general formula (G7)>

[0466] Next, an example of a method for synthesizing an iridium complex having a structure represented by the general formula (G7) is described.

[0467] 《Synthesis method of 1H-1,2,4-triazole derivatives》

[0468] First, an example of a method for synthesizing a 1H-1,2,4-triazole derivative represented by the following general formula (G0-X4) is described.

[0469]

[0470] In the general formula (G0-X4), Ar 1 represents a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. 1 To R 4 R each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. 6 represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a halogenated alkyl group having 1 to 6 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. 1 , R 1 To R 4 and R 6 The aryl group and R 1 To R 4 At least one of them has a cyano group.

[0471] As shown in the following synthesis scheme (d), a 1H-1,2,4-triazole derivative can be obtained by reacting an acylamidine compound (C1) with a hydrazine compound (C2). In addition, Z in the formula represents a group (leaving group) that is released by the ring-closing reaction, and examples thereof include alkoxy, alkylthio, amino, and cyano. In the above synthesis scheme (d), Ar 1 represents a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. 1 To R 4 R each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. 6 represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a halogenated alkyl group having 1 to 6 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. 1 , R 1 To R 4 and R 6 The aryl group and R 1 To R 4 At least one of them has a cyano group.

[0472]

[0473] Note that the synthesis method of 1H-1,2,4-triazole derivatives is not limited to the synthesis scheme (d). As described above, 1H-1,2,4-triazole derivatives represented by the general formula (G0-X4) can be synthesized by a simple synthesis scheme.

[0474] Then, by the same synthesis method as the above-mentioned synthesis scheme (a), a 1H-1,2,4-triazole derivative represented by the general formula (G0-X4) is mixed with an iridium metal compound containing a halogen (iridium chloride hydrate, ammonium hexachloroiridate, etc.) or an iridium organometallic complex compound (acetylacetonate complex, diethyl sulfide complex, etc.) and then heated, thereby obtaining an iridium complex having a structure represented by the general formula (G7).

[0475] The compound described in this embodiment mode can be used in combination with the structure described in other embodiments mode as appropriate.

[0476] Implementation 4

[0477] In this embodiment, refer to Figure 3A and Figure 3B A structural example of the light-emitting element using the iridium complex described in Embodiment 2 is described.

[0478] <Structural Example of Light Emitting Element>

[0479] Figure 3A It is a schematic cross-sectional view of a light emitting element 152 according to one embodiment of the present invention.

[0480] The light-emitting element 152 includes an EL layer 100 between a pair of electrodes. One layer of the EL layer 100 includes the iridium complex described in Embodiment 2.

[0481] The EL layer 100 includes at least a light-emitting layer 140. The EL layer 100 may have a structure including the hole injection layer 111, the hole transport layer 112, the electron transport layer 118, and the electron injection layer 119 described in Embodiment 1 in addition to the light-emitting layer 140. Note that the stacked-layer structure of the EL layer 100 is not limited to this.

[0482] In this embodiment, the materials described in Embodiment 1 can be used for the pair of electrodes (electrode 101 and electrode 102 ), the hole injection layer 111 , the hole transport layer 112 , the electron transport layer 118 , and the electron injection layer 119 .

[0483] in addition, Figure 3B 1 is a schematic cross-sectional view showing an example of a light-emitting layer 140 included in the light-emitting element 152. The light-emitting layer 140 includes a host material 141 and a guest material 142. As the host material 141, the material described in the host material 131 in Embodiment Mode 1 can be used. That is, as the organic compound 141_1 and the organic compound 141_2 included in the host material 141, the materials described in the organic compound 131_1 and the organic compound 131_2 in Embodiment Mode 1 can be used, respectively.

[0484] In addition, since the iridium complex described in Embodiment 2 has a relatively low HOMO energy level and a relatively low LUMO energy level, it is suitable for a guest material of a light-emitting element of one embodiment of the present invention. That is, by using the iridium complex described in Embodiment 2 as a guest material 142 of a light-emitting element 152, a light-emitting element with high luminous efficiency can be manufactured. In addition, since the triplet excitation energy level of the iridium complex is relatively high, a light-emitting element with high luminous efficiency and a blue color can be manufactured. Therefore, by adopting the structure of this embodiment, a light-emitting element with high luminous efficiency and an emission spectrum peak in a blue wavelength range can be manufactured. In addition, since the iridium complex has a high tolerance to repeated oxidation and reduction, a light-emitting element with a long driving life can be manufactured.

[0485] In addition, Figure 2A and Figure 2B Similarly to the light-emitting mechanism shown in the embodiment 2, the HOMO energy level of the guest material 142 is preferably lower than the HOMO energy level of the organic compound 141_2, and the LUMO energy level of the guest material 142 is preferably higher than the LUMO energy level of the organic compound 141_1. Since the iridium complex shown in Embodiment 2 has a lower HOMO energy level and LUMO energy level, it can be applied to the guest material of the above structure. In other words, the organic compound 141_1, the organic compound 141_2 and the guest material 142 can be selected in such a way that the energy difference between the LUMO energy level and the HOMO energy level of the guest material 142 is greater than the energy difference between the LUMO energy level of the organic compound 141_1 and the HOMO energy level of the organic compound 141_2. As the guest material 142, the iridium complex shown in Embodiment 2 is preferably used. By adopting the above structure, the formation of an exciplex by the guest material 142 and the organic compound 141_1 or the organic compound 141_2 can be suppressed, thereby manufacturing a light-emitting element with high light-emitting efficiency.

[0486] In addition, the iridium complex shown in Embodiment 2 has a function of converting triplet excitation energy into luminescence. Thus, the iridium complex can present luminescence whose energy is less than the energy difference between the LUMO energy level and the HOMO energy level. Therefore, if the luminescence or absorption energy presented by the iridium complex is less than the energy difference between the LUMO energy level of the organic compound 141_1 and the HOMO energy level of the organic compound 141_2, even if the energy difference between the LUMO energy level and the HOMO energy level of the iridium complex is greater than the energy difference between the LUMO energy level of the organic compound 141_1 and the HOMO energy level of the organic compound 141_2, the excitation energy can be transferred from the exciplex formed by the organic compound 141_1 and the organic compound 141_2 to the iridium complex, thereby obtaining luminescence from the iridium complex.

[0487] In addition, the oxidation potential of the guest material 142 is preferably higher than the oxidation potential of the organic compound 141_2, and the reduction potential of the guest material 142 is preferably lower than the reduction potential of the organic compound 141_1. Since the iridium complex shown in Embodiment 2 has a high oxidation potential and a reduction potential, it can be applied to the guest material of the above structure. By adopting the above structure, the formation of an exciplex by the guest material 142 and the organic compound 141_1 or the organic compound 141_2 can be suppressed, thereby manufacturing a light-emitting element with high luminous efficiency. The oxidation potential and the reduction potential are measured by using a cyclic voltammetry (CV) method.

[0488] The light-emitting layer 140 may also be formed of a plurality of layers of more than two layers. For example, in the case where the light-emitting layer 140 is formed by stacking the first light-emitting layer and the second light-emitting layer in sequence from the hole transport layer side, a substance having a hole transport property may be used as the main material of the first light-emitting layer, and a substance having an electron transport property may be used as the main material of the second light-emitting layer. In addition, the light-emitting materials contained in the first light-emitting layer and the second light-emitting layer may also be the same or different materials. In addition, the light-emitting materials contained in the first light-emitting layer and the second light-emitting layer may be materials having the function of emitting light of the same color or materials having the function of emitting light of different colors. By using light-emitting materials having the function of emitting light of different colors from each other as two light-emitting layers, multiple light-emittings can be obtained at the same time. In particular, it is preferred to select the light-emitting materials used for each light-emitting layer so that white light emission can be obtained by combining the light emitted by the two light-emitting layers.

[0489] In addition, the light-emitting layer 140 may contain materials other than the host material 141 and the guest material 142 .

[0490] The light emitting layer 140 may be formed by evaporation (including vacuum evaporation), inkjet, coating, gravure printing, etc. In addition to the above materials, inorganic compounds such as quantum dots or high molecular compounds (oligomers, dendrimers, polymers, etc.) may also be included.

[0491] Note that for other structures of the light-emitting element 152 described in this embodiment, the structure of the light-emitting element 150 described in Embodiment 1 can be referred to.

[0492] The structure described in this embodiment mode can be used in combination with the structures described in other embodiment modes as appropriate.

[0493] Implementation method 5

[0494] In this embodiment, refer to Figure 4 A light-emitting element having a structure different from that described in Embodiment Modes 1 and 4 will be described. Figure 4 Use with Figure 1A The same hatching shows Figure 1A The same function as the part, and sometimes the reference numeral is omitted. Figure 1A Components with the same functions are denoted by the same reference numerals, and detailed description thereof may be omitted.

[0495] Figure 4 is a schematic cross-sectional view of the light emitting element 250 .

[0496] Figure 4 The light emitting element 250 shown has a plurality of light emitting units ( Figure 4 One of the plurality of light emitting units preferably has a light emitting unit 106 and a light emitting unit 108. Figure 1A and Figure 1B or Figure 3A and Figure 3B The EL layer 100 has the same structure as shown. That is, Figure 1A and Figure 1B The light emitting element 150 and Figure 3A and Figure 3B The light emitting element 152 shown preferably has one light emitting unit, whereas the light emitting element 250 preferably has a plurality of light emitting units. Note that in the light emitting element 250, although the electrode 101 is an anode and the electrode 102 is a cathode, the structure of the light emitting element 250 may be the opposite.

[0497] In addition, Figure 4 In the light emitting element 250 shown in FIG. 1 , the light emitting unit 106 and the light emitting unit 108 are stacked, and the charge generating layer 115 is provided between the light emitting unit 106 and the light emitting unit 108. In addition, the light emitting unit 106 and the light emitting unit 108 may have the same structure or different structures. For example, it is preferable to Figure 1A and Figure 1B or Figure 3A and Figure 3B The EL layer 100 shown is suitable for use in the light emitting unit 108 .

[0498] In addition, the light-emitting element 250 includes a light-emitting layer 170 and a light-emitting layer 180. In addition, the light-emitting unit 106 includes a hole injection layer 111, a hole transport layer 112, an electron transport layer 113, and an electron injection layer 114 in addition to the light-emitting layer 170. In addition, the light-emitting unit 108 includes a hole injection layer 116, a hole transport layer 117, an electron transport layer 118, and an electron injection layer 119 in addition to the light-emitting layer 180.

[0499] The charge generation layer 115 may have a structure in which an acceptor substance serving as an electron acceptor is added to a hole transport material, or a structure in which a donor substance serving as an electron donor is added to an electron transport material. Alternatively, these two structures may be stacked.

[0500] When the charge generation layer 115 includes a composite material composed of an organic compound and an acceptor substance, the composite material that can be used for the hole injection layer 111 described in Embodiment 1 can be used as the composite material. As the organic compound, various compounds such as aromatic amine compounds, carbazole compounds, aromatic hydrocarbons, and high molecular weight compounds (oligomers, dendrimers, polymers, etc.) can be used. In addition, as the organic compound, it is preferred to use an organic compound having a hole mobility of 1×10 -6 cm 2 / Vs or more. However, as long as the hole transport property is higher than the electron transport property, substances other than these can be used. Because the composite material composed of organic compounds and acceptor substances has good carrier injection and carrier transport properties, low voltage drive and low current drive can be achieved. Note that when the surface on the anode side of the light-emitting unit contacts the charge generation layer 115, as in the light-emitting unit 108, the charge generation layer 115 can also have the function of the hole injection layer or hole transport layer of the light-emitting unit, so the light-emitting unit can also have a structure without a hole injection layer or a hole transport layer.

[0501] Note that the charge generation layer 115 may also have a stacked structure of a layer containing a composite material of an organic compound and an acceptor substance and a layer containing other materials. For example, the charge generation layer 115 may also be formed using a combination of a layer containing a composite material of an organic compound and an acceptor substance and a layer containing a compound selected from electron-donating substances and a compound with high electron transport properties. Alternatively, the charge generation layer 115 may also be formed using a combination of a layer containing a composite material of an organic compound and an acceptor substance and a layer containing a transparent conductive material.

[0502] The charge generation layer 115 sandwiched between the light-emitting unit 106 and the light-emitting unit 108 may have a structure that injects electrons into one light-emitting unit and injects holes into the other light-emitting unit when a voltage is applied between the electrode 101 and the electrode 102. Figure 4 In the embodiment, when a voltage is applied so that the potential of the electrode 101 is higher than the potential of the electrode 102 , the charge generation layer 115 injects electrons into the light-emitting unit 106 and injects holes into the light-emitting unit 108 .

[0503] From the viewpoint of light extraction efficiency, the charge generation layer 115 preferably has visible light transmittance (specifically, the charge generation layer 115 has a visible light transmittance of 40% or more). The charge generation layer 115 functions even if its conductivity is lower than that of the pair of electrodes (electrode 101 and electrode 102).

[0504] By forming the charge generation layer 115 using the above-mentioned material, an increase in driving voltage when a light-emitting layer is stacked can be suppressed.

[0505] Although in Figure 4 , a light-emitting element having two light-emitting units is described, but the same structure can be applied to a light-emitting element having three or more light-emitting units stacked. As shown in light-emitting element 250, by arranging a plurality of light-emitting units between a pair of electrodes in a manner separated by a charge generation layer, a light-emitting element that can emit light at high brightness while maintaining a low current density and has a longer service life can be realized. In addition, a light-emitting element with low power consumption can also be realized.

[0506] In addition, by applying the structure described in Embodiment 1 to Embodiment 4 to at least one of a plurality of units, a light-emitting element with high light emission efficiency can be provided.

[0507] In addition, in each of the above structures, the guest materials (luminescent materials) used for the light-emitting unit 106 and the light-emitting unit 108 may be the same or different. When the light-emitting unit 106 and the light-emitting unit 108 include guest materials having the function of presenting the same color, the light-emitting element 250 becomes a light-emitting element that presents high luminous brightness at a small current value, so it is preferred. In addition, when the light-emitting unit 106 and the light-emitting unit 108 include guest materials having the function of presenting light of different colors from each other, the light-emitting element 250 becomes a light-emitting element that presents multi-color light emission, so it is preferred. At this time, since a plurality of light-emitting substances with different luminescent wavelengths are used as one or both of the light-emitting layer 170 and the light-emitting layer 180, light with different luminescent peaks is synthesized, the emission spectrum presented by the light-emitting element 250 has at least two peaks.

[0508] The above structure is suitable for obtaining white light emission. White light emission can be obtained by making the light of the light emitting layer 170 and the light emitting layer 180 complementary colors. It is particularly preferred to select the guest material in a manner that realizes white light emission with high color rendering index or light emission having at least red, green, and blue.

[0509] In addition, either or both of the light-emitting layer 170 and the light-emitting layer 180 may be further divided into layers and each of the divided layers may contain a different light-emitting material. That is, one or both of the light-emitting layer 170 and the light-emitting layer 180 may also be formed by a plurality of layers of two or more. For example, in the case where the light-emitting layer is formed by stacking the first light-emitting layer and the second light-emitting layer in sequence from the hole transport layer side, a substance having a hole transport property may be used as the main material of the first light-emitting layer, and a substance having an electron transport property may be used as the main material of the second light-emitting layer. In this case, the light-emitting materials contained in the first light-emitting layer and the second light-emitting layer may also be the same or different materials. In addition, the light-emitting materials contained in the first light-emitting layer and the second light-emitting layer may be materials having the function of emitting light of the same color or materials having the function of emitting light of different colors. By adopting a structure of multiple light-emitting materials having the function of emitting light of different colors from each other, white light with high color rendering properties consisting of three primary colors or four or more light-emitting colors may also be obtained.

[0510] Materials that can be used for the light-emitting layer 170 and the light-emitting layer 180 may be materials that can be used for the light-emitting layer 130 described in Embodiment 1 and the light-emitting layer 140 described in Embodiment 4. In addition, as the guest material, the iridium complex described in Embodiment 2 is preferably used. In this way, a light-emitting element with high light emission efficiency can be manufactured.

[0511] Alternatively, the light-emitting unit 106, the light-emitting unit 108, and the charge generation layer 115 can be formed by a method such as an evaporation method (including a vacuum evaporation method), an inkjet method, a coating method, or a gravure printing method.

[0512] The structure described in this embodiment mode can be used in combination with the structures described in other embodiment modes as appropriate.

[0513] Implementation 6

[0514] In this embodiment, refer to FIG. 5A to FIG. 8C Examples of light-emitting elements having a structure different from the structures described in Embodiments 1, 4, and 5 are described.

[0515] <Structural Example 1 of Light Emitting Element>

[0516] Figure 5A and Figure 5B 1 is a cross-sectional view showing a light-emitting element according to one embodiment of the present invention. Figure 5A and Figure 5B Use with Figure 1A The same hatching shows Figure 1A The same function as the part, and sometimes the reference numeral is omitted. Figure 1AParts having the same functions as shown are denoted by the same reference numerals, and detailed description thereof may be omitted.

[0517] Figure 5A and Figure 5B The light emitting element 260a and the light emitting element 260b shown may be a bottom emission type light emitting element that extracts light through the substrate 200, or a top emission type light emitting element that extracts light in a direction opposite to the substrate 200. Note that one embodiment of the present invention is not limited to this, and a dual-emission type light emitting element that extracts light emitted by the light emitting element to both above and below the substrate 200 may also be used.

[0518] When both the light-emitting element 260a and the light-emitting element 260b are bottom emission types, the electrode 101 preferably has a function of transmitting light. In addition, the electrode 102 preferably has a function of reflecting light. Alternatively, when the light-emitting element 260a and the light-emitting element 260b are top emission types, the electrode 101 preferably has a function of reflecting light. In addition, the electrode 102 preferably has a function of transmitting light.

[0519] Both the light-emitting element 260a and the light-emitting element 260b include an electrode 101 and an electrode 102 on a substrate 200. In addition, a light-emitting layer 123B, a light-emitting layer 123G, and a light-emitting layer 123R are included between the electrode 101 and the electrode 102. In addition, a hole injection layer 111, a hole transport layer 112, an electron transport layer 118, and an electron injection layer 119 are also included.

[0520] Light-emitting element 260b includes conductive layer 101a, conductive layer 101b on conductive layer 101a, and conductive layer 101c under conductive layer 101a as part of the structure of electrode 101. In other words, light-emitting element 260b has the structure of electrode 101 in which conductive layer 101a is sandwiched between conductive layer 101b and conductive layer 101c.

[0521] In the light emitting element 260b, the conductive layer 101b and the conductive layer 101c may be formed of different materials or the same material. When the electrode 101 has a structure in which the conductive layer 101a is sandwiched by layers formed of the same conductive material, patterning is easily performed by an etching step during the formation of the electrode 101, which is preferred.

[0522] Alternatively, the light-emitting element 260b may include only one of the conductive layer 101b and the conductive layer 101c.

[0523] In addition, the conductive layers 101a, 101b, and 101c included in the electrode 101 can have the same structure and material as those of the electrode 101 or the electrode 102 described in Embodiment 1.

[0524] exist Figure 5A and Figure 5B In the embodiment, a partition wall 145 is provided between the region 221B, the region 221G and the region 221R sandwiched between the electrode 101 and the electrode 102. The partition wall 145 has insulating properties. The partition wall 145 covers the end of the electrode 101 and has an opening overlapping the electrode. By providing the partition wall 145, the electrode 101 on the substrate 200 in each region can be divided into island shapes.

[0525] In addition, the light-emitting layer 123B and the light-emitting layer 123G may have a region overlapping with each other in the region overlapping with the partition wall 145. In addition, the light-emitting layer 123G and the light-emitting layer 123R may have a region overlapping with each other in the region overlapping with the partition wall 145. In addition, the light-emitting layer 123R and the light-emitting layer 123B may have a region overlapping with each other in the region overlapping with the partition wall 145.

[0526] The partition wall 145 may be formed of an inorganic material or an organic material as long as it has insulating properties. Examples of the inorganic material include silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, aluminum oxide, and aluminum nitride. Examples of the organic material include photosensitive resin materials such as acrylic resins and polyimide resins.

[0527] Note that the oxynitride silicon film refers to a film in which the oxygen content is higher than the nitrogen content in its composition, and preferably contains oxygen, nitrogen, silicon, and hydrogen in a concentration range of 55 atoms% to 65 atoms%, 1 atoms% to 20 atoms%, 25 atoms% to 35 atoms%, and 0.1 atoms% to 10 atoms%, respectively. The nitride silicon oxide film refers to a film in which the nitrogen content is higher than the oxygen content in its composition, and preferably contains nitrogen, oxygen, silicon, and hydrogen in a concentration range of 55 atoms% to 65 atoms%, 1 atoms% to 20 atoms%, 25 atoms% to 35 atoms%, and 0.1 atoms% to 10 atoms%, respectively.

[0528] In addition, the light-emitting layer 123R, the light-emitting layer 123G, and the light-emitting layer 123B preferably contain light-emitting materials capable of emitting different colors, respectively. For example, when the light-emitting layer 123R contains a light-emitting material capable of emitting red, the region 221R presents red light; when the light-emitting layer 123G contains a light-emitting material capable of emitting green, the region 221G presents green light; when the light-emitting layer 123B contains a light-emitting material capable of emitting blue, the region 221B presents blue light. By using the light-emitting element 260a or the light-emitting element 260b having such a structure for the pixels of the display device, a display device capable of full-color display can be manufactured. In addition, the film thickness of each light-emitting layer can be the same or different.

[0529] In addition, any one or more of the light-emitting layer 123B, the light-emitting layer 123G, and the light-emitting layer 123R preferably includes at least one of the light-emitting layer 130 described in Embodiment 1 and the light-emitting layer 140 described in Embodiment 4. In addition, as a light-emitting material, any one or more of the light-emitting layer 123B, the light-emitting layer 123G, and the light-emitting layer 123R preferably includes the iridium complex described in Embodiment 2. In this way, a light-emitting element with good light-emitting efficiency can be manufactured.

[0530] In addition, any one or more of the light-emitting layer 123B, the light-emitting layer 123G, and the light-emitting layer 123R may be a stack of two or more layers.

[0531] As described above, by making at least one light-emitting layer include the light-emitting layer described in Embodiment 1 and Embodiment 4 or the light-emitting material described in Embodiment 2, and using the light-emitting element 260a or the light-emitting element 260b including the light-emitting layer for a pixel of the display device, a display device with high light-emitting efficiency can be manufactured. That is, the display device including the light-emitting element 260a or the light-emitting element 260b can reduce power consumption.

[0532] In addition, by providing an optical element (e.g., a color filter, a polarizing plate, an anti-reflection film) on the light extraction side of the light extraction electrode, the color purity of the light-emitting element 260a and the light-emitting element 260b can be improved. Therefore, the color purity of the display device including the light-emitting element 260a or the light-emitting element 260b can be improved. In addition, the external light reflection of the light-emitting element 260a and the light-emitting element 260b can be reduced. Therefore, the contrast of the display device including the light-emitting element 260a or the light-emitting element 260b can be improved.

[0533] Note that for other components of the light-emitting element 260a and the light-emitting element 260b, the components of the light-emitting element in Embodiment 1, Embodiment 4, or Embodiment 5 may be referred to.

[0534] <Structural Example 2 of Light Emitting Element>

[0535] Below, refer to Fig. 6A and Figure 6B Description and Figure 5A and Figure 5B The light emitting elements shown are different structural examples.

[0536] Fig. 6A and Figure 6B 1 is a cross-sectional view showing a light-emitting element according to one embodiment of the present invention. Fig. 6A and Figure 6B Use with Figure 5A and Figure 5B The same hatching shows Figure 5A and Figure 5B The same function as the part, and sometimes the reference numeral is omitted. Figure 5A and Figure 5B Parts having the same functions as shown are denoted by the same reference numerals, and detailed description thereof may be omitted.

[0537] Fig. 6A and Figure 6B This is an example of the structure of a light-emitting element having a light-emitting layer between a pair of electrodes. Fig. 6A The light emitting element 262a shown is a top emission type light emitting element that extracts light in a direction opposite to the substrate 200, and Figure 6B The light emitting element 262b shown is a bottom emission type light emitting element that extracts light through the substrate 200. Note that one embodiment of the present invention is not limited to this, and a dual emission type light emitting element that extracts light emitted by the light emitting element to both above and below the substrate 200 on which the light emitting element is formed may be used.

[0538] The light-emitting element 262a and the light-emitting element 262b both include an electrode 101, an electrode 102, an electrode 103, and an electrode 104 on a substrate 200. In addition, between the electrode 101 and the electrode 102, between the electrode 102 and the electrode 103, and between the electrode 102 and the electrode 104, at least a light-emitting layer 170, a light-emitting layer 190, and a charge generation layer 115 are included. In addition, a hole injection layer 111, a hole transport layer 112, an electron transport layer 113, an electron injection layer 114, a hole injection layer 116, a hole transport layer 117, an electron transport layer 118, and an electron injection layer 119 are also included.

[0539] Electrode 101 includes conductive layer 101a and conductive layer 101b on and in contact with conductive layer 101a. In addition, electrode 103 includes conductive layer 103a and conductive layer 103b on and in contact with conductive layer 103a. Electrode 104 includes conductive layer 104a and conductive layer 104b on and in contact with conductive layer 104a.

[0540] Fig. 6AThe light emitting element 262a and Figure 6B The light emitting element 262b shown includes a partition wall 145 between a region 222B sandwiched by the electrode 101 and the electrode 102, a region 222G sandwiched by the electrode 102 and the electrode 103, and a region 222R sandwiched by the electrode 102 and the electrode 104. The partition wall 145 has an insulating property. The partition wall 145 covers the ends of the electrode 101, the electrode 103, and the electrode 104, and includes an opening portion overlapping the electrode. By providing the partition wall 145, the electrode on the substrate 200 in each region can be divided into island shapes.

[0541] The charge generation layer 115 can be formed by using a material in which an electron acceptor (acceptor) is added to a hole transport material or a material in which an electron donor (donor) is added to an electron transport material. When the conductivity of the charge generation layer 115 is approximately the same as that of a pair of electrodes, since carriers generated by the charge generation layer 115 are transferred to adjacent pixels, adjacent pixels sometimes emit light. Therefore, in order to suppress abnormal light emission of adjacent pixels, the charge generation layer 115 is preferably formed using a material with a lower conductivity than that of the pair of electrodes.

[0542] The light emitting element 262a and the light emitting element 262b both include a substrate 220 provided with an optical element 224B, an optical element 224G, and an optical element 224R in the direction in which the light emitted from the region 222B, the region 222G, and the region 222R is extracted. The light emitted from each region is emitted to the outside of the light emitting element through each optical element. That is, the light emitted from the region 222B is emitted through the optical element 224B, the light emitted from the region 222G is emitted through the optical element 224G, and the light emitted from the region 222R is emitted through the optical element 224R.

[0543] The optical element 224B, the optical element 224G, and the optical element 224R all have the function of selectively transmitting light of a specific color among the incident light. For example, the light emitted from the region 222B is transmitted through the optical element 224B to become blue light, the light emitted from the region 222G is transmitted through the optical element 224G to become green light, and the light emitted from the region 222R is transmitted through the optical element 224R to become red light.

[0544] As the optical element 224R, the optical element 224G, and the optical element 224B, for example, a coloring layer (also referred to as a color filter), a bandpass filter, a multilayer film filter, etc. can be used. In addition, a color conversion element can be used as an optical element. The color conversion element is an optical element that converts incident light into light whose wavelength is longer than that of the incident light. As the color conversion element, an element using quantum dots is preferably used. By using quantum dots, the color reproducibility of the display device can be improved.

[0545] In addition, one or more other optical elements may be arranged overlappingly on the optical element 224R, the optical element 224G, and the optical element 224B. As other optical elements, for example, a circular polarizer or an anti-reflection film may be arranged. By arranging the circular polarizer on the side where the light emitted by the light-emitting element in the display device is extracted, it is possible to prevent the light incident from the outside of the display device from being reflected inside the display device and emitted to the outside. In addition, by arranging the anti-reflection film, the external light reflected on the surface of the display device can be weakened. Thus, the light emitted by the display device can be clearly observed.

[0546] exist Fig. 6A and Figure 6B The blue (B) light, green (G) light, and red (R) light emitted from each region through each optical element are schematically shown by the dotted arrows.

[0547] A light shielding layer 223 is included between each optical element. The light shielding layer 223 has a function of shielding light emitted from an adjacent region. Alternatively, a structure without the light shielding layer 223 may be adopted.

[0548] The light shielding layer 223 has a function of suppressing reflection of external light. In addition, the light shielding layer 223 has a function of preventing mixing of light emitted from adjacent light emitting elements. The light shielding layer 223 can be made of metal, resin containing black pigment, carbon black, metal oxide, composite oxide containing a solid solution of multiple metal oxides, etc.

[0549] In addition, the optical element 224B and the optical element 224G may have overlapping regions in the region overlapping with the light shielding layer 223. In addition, the optical element 224G and the optical element 224R may have overlapping regions in the region overlapping with the light shielding layer 223. In addition, the optical element 224R and the optical element 224B may have overlapping regions in the region overlapping with the light shielding layer 223.

[0550] In addition, regarding the structures of the substrate 200 and the substrate 220 having an optical element, refer to Embodiment Mode 1.

[0551] Furthermore, the light emitting element 262a and the light emitting element 262b have a microcavity structure.

[0552] Microcavity structure

[0553] The light emitted from the light emitting layer 170 and the light emitting layer 190 is resonated between a pair of electrodes (for example, the electrode 101 and the electrode 102). In addition, the light emitting layer 170 and the light emitting layer 190 are formed at positions where the light of a desired wavelength in the emitted light is enhanced. For example, by adjusting the optical distance from the reflection area of ​​the electrode 101 to the light emitting area of ​​the light emitting layer 170 and the optical distance from the reflection area of ​​the electrode 102 to the light emitting area of ​​the light emitting layer 170, the light of a desired wavelength in the light emitted from the light emitting layer 170 can be enhanced. In addition, by adjusting the optical distance from the reflection area of ​​the electrode 101 to the light emitting area of ​​the light emitting layer 190 and the optical distance from the reflection area of ​​the electrode 102 to the light emitting area of ​​the light emitting layer 190, the light of a desired wavelength in the light emitted from the light emitting layer 190 can be enhanced. That is, when a light emitting element in which a plurality of light emitting layers (here, the light emitting layer 170 and the light emitting layer 190) are stacked is used, it is preferable to optimize the optical distances of the light emitting layer 170 and the light emitting layer 190, respectively.

[0554] In the light-emitting element 262a and the light-emitting element 262b, by adjusting the thickness of the conductive layer (the conductive layer 101b, the conductive layer 103b, and the conductive layer 104b) in each region, it is possible to enhance light of a desired wavelength among the light emitted by the light-emitting layer 170 and the light-emitting layer 190. In order to enhance the light emitted from the light-emitting layer 170 and the light-emitting layer 190, the thickness of at least one of the hole injection layer 111 and the hole transport layer 112 may be different in each region.

[0555] For example, when the refractive index of the conductive material capable of reflecting light in the electrodes 101 to 104 is smaller than the refractive index of the light-emitting layer 170 or the light-emitting layer 190, the optical distance between the electrode 101 and the electrode 102 is m. B λ B / 2(m B represents a natural number, λ B The film thickness of the conductive layer 101b in the electrode 101 is adjusted in such a manner as to represent the wavelength of light enhanced in the region 222B. Similarly, when the optical distance between the electrode 103 and the electrode 102 is m G λ G / 2(m G represents a natural number, λ G The film thickness of the conductive layer 103b in the electrode 103 is adjusted in such a manner as to have a wavelength of light enhanced in the region 222G. And, the optical distance between the electrode 104 and the electrode 102 is m. R λ R / 2(m R represents a natural number, λ R The film thickness of the conductive layer 104b in the electrode 104 is adjusted in a manner (indicating the wavelength of light enhanced in the region 222R).

[0556] For example, when it is difficult to strictly determine the reflection region of the electrodes 101 to 104, it is possible to derive an optical distance that enhances the light emitted from the light-emitting layer 170 or the light-emitting layer 190 by assuming that any region of the electrodes 101 to 104 is set as the reflection region. In addition, when it is difficult to strictly determine the light-emitting region of the light-emitting layer 170 and the light-emitting layer 190, it is possible to derive an optical distance that enhances the light emitted from the light-emitting layer 170 and the light-emitting layer 190 by assuming that any region of the light-emitting layer 170 and the light-emitting layer 190 is set as the light-emitting region.

[0557] As described above, by providing a microcavity structure to adjust the optical distance between a pair of electrodes in each region, light scattering and light absorption near each electrode can be suppressed, thereby achieving high light extraction efficiency.

[0558] In the above structure, the conductive layer 101b, the conductive layer 103b, and the conductive layer 104b preferably have a function of transmitting light. In addition, the materials constituting the conductive layer 101b, the conductive layer 103b, and the conductive layer 104b may be the same or different. When the conductive layer 101b, the conductive layer 103b, and the conductive layer 104b are formed using the same material, it is preferred because the formation of the pattern through the etching process in the formation process of the electrode 101, the electrode 103, and the electrode 104 becomes easy. In addition, the conductive layer 101b, the conductive layer 103b, and the conductive layer 104b may be a stack of two or more layers.

[0559] because Fig. 6A The light-emitting element 262a shown is a top-emission light-emitting element, and therefore the conductive layer 101a, the conductive layer 103a, and the conductive layer 104a preferably have a function of reflecting light. In addition, the electrode 102 preferably has a function of transmitting light and a function of reflecting light.

[0560] In addition, due to Figure 6B The light-emitting element 262b shown is a bottom emission type light-emitting element, and therefore the conductive layer 101a, the conductive layer 103a, and the conductive layer 104a preferably have a function of transmitting light and a function of reflecting light. In addition, the electrode 102 preferably has a function of reflecting light.

[0561] In the light emitting element 262a and the light emitting element 262b, the conductive layer 101a, the conductive layer 103a, and the conductive layer 104a may be made of the same material or different materials. When the conductive layer 101a, the conductive layer 103a, and the conductive layer 104a are made of the same material, the manufacturing cost of the light emitting element 262a and the light emitting element 262b can be reduced. In addition, the conductive layer 101a, the conductive layer 103a, and the conductive layer 104a may be a stack of two or more layers.

[0562] In addition, at least one of the light-emitting layer 170 and the light-emitting layer 190 in the light-emitting element 262a and the light-emitting element 262b preferably has at least one of the structures described in Embodiment 1 and Embodiment 4. In addition, as the light-emitting material, it is preferable to include the iridium complex described in Embodiment 2. In this way, a light-emitting element with high light emission efficiency can be manufactured.

[0563] For example, one or both of the light-emitting layer 170 and the light-emitting layer 190 may have a structure in which two layers are stacked, such as the light-emitting layer 190a and the light-emitting layer 190b. By using the first compound and the second compound, two light-emitting materials having the function of emitting different colors, as the two light-emitting layers, respectively, light emission including multiple colors can be obtained. In particular, it is preferable to select the light-emitting material of each light-emitting layer so that white light emission can be obtained by combining the light emitted by the light-emitting layer 170 and the light-emitting layer 190.

[0564] One or both of the light-emitting layer 170 and the light-emitting layer 190 may have a structure in which three or more layers are stacked, and these layers may include a layer having no light-emitting material.

[0565] As described above, a display device having high light emission efficiency can be manufactured by using the light-emitting element 262a or the light-emitting element 262b having at least one of the structures of the light-emitting layer described in Embodiment 1 to Embodiment 4 in a pixel of the display device. That is, a display device including the light-emitting element 262a or the light-emitting element 262b can reduce power consumption.

[0566] Note that other components of the light-emitting element 262a and the light-emitting element 262b can refer to the components of the light-emitting element 260a or the light-emitting element 260b or the light-emitting elements described in Embodiment 1, Embodiment 4, and Embodiment 5.

[0567] <Method for manufacturing light-emitting element>

[0568] Next, refer to 7A to 8C A method for manufacturing a light-emitting element according to one embodiment of the present invention is described below. Fig. 6A A method for manufacturing the light emitting element 262a shown in FIG.

[0569] 7A to 8C It is a cross-sectional view for explaining a method for manufacturing a light-emitting element according to one embodiment of the present invention.

[0570] The method for manufacturing the light emitting element 262 a to be described below includes seven steps from a first step to a seventh step.

[0571] First Step

[0572] The first step is a process of forming electrodes of the light emitting element (specifically, the conductive layer 101a of the electrode 101, the conductive layer 103a of the electrode 103, and the conductive layer 104a of the electrode 104) on the substrate 200 (see Fig. 7A ).

[0573] In this embodiment, a conductive layer having a function of reflecting light is formed on the substrate 200, and the conductive layer is processed into a desired shape, thereby forming the conductive layer 101a, the conductive layer 103a, and the conductive layer 104a. As the conductive layer having a function of reflecting light, an alloy film of silver, palladium, and copper (also referred to as an Ag-Pd-Cu film or APC) is used. In this way, by forming the conductive layer 101a, the conductive layer 103a, and the conductive layer 104a through a process of processing the same conductive layer, the manufacturing cost can be reduced, which is preferred.

[0574] Alternatively, before the first step, a plurality of transistors may be formed over the substrate 200. Alternatively, the plurality of transistors may be electrically connected to the conductive layer 101a, the conductive layer 103a, and the conductive layer 104a.

[0575] Second Step

[0576] The second step is a process of forming a transparent conductive layer 101b having a light transmitting function on the conductive layer 101a of the electrode 101; forming a transparent conductive layer 103b having a light transmitting function on the conductive layer 103a of the electrode 103; and forming a transparent conductive layer 104b having a light transmitting function on the conductive layer 104a of the electrode 104 (see Figure 7B ).

[0577] In this embodiment, conductive layers 101b, 103b, and 104b having a function of transmitting light are formed on conductive layers 101a, 103a, and 104a having a function of reflecting light, respectively, thereby forming electrodes 101, 103, and 104. ITSO films are used as the conductive layers 101b, 103b, and 104b.

[0578] Alternatively, the conductive layers 101b, 103b, and 104b having a function of transmitting light may be formed in a plurality of steps. By forming the conductive layers 101b, 103b, and 104b in a plurality of steps, the conductive layers 101b, 103b, and 104b can be formed with a film thickness that allows an appropriate microcavity structure to be realized in each region.

[0579] The Third Step

[0580] The third step is a step of forming a partition wall 145 covering the end portions of each electrode of the light emitting element (see Figure 7C ).

[0581] The partition wall 145 includes an opening that overlaps with the electrode. The conductive film exposed by the opening is used as an anode of the light-emitting element. In this embodiment, a polyimide resin is used as the partition wall 145.

[0582] In addition, there is no possibility of damaging the EL layer (layer containing an organic compound) in the first step to the third step, and thus various formation methods and micro-fabrication techniques can be used. In this embodiment, a reflective conductive layer is formed by sputtering, a pattern is formed on the conductive layer by photolithography, and then the conductive layer is processed into an island shape by dry etching or wet etching to form the conductive layer 101a of the electrode 101, the conductive layer 103a of the electrode 103, and the conductive layer 104a of the electrode 104. Then, a transparent conductive film is formed by sputtering, a pattern is formed on the transparent conductive film by photolithography, and then the transparent conductive film is processed into an island shape by wet etching to form the electrodes 101, the electrode 103, and the electrode 104.

[0583] Step 4

[0584] The fourth step is a process of forming the hole injection layer 111, the hole transport layer 112, the light emitting layer 190, the electron transport layer 113, the electron injection layer 114 and the charge generation layer 115 (see Fig. 8A ).

[0585] The hole injection layer 111 can be formed by co-evaporating a hole transport material and a material containing an acceptor substance. Note that co-evaporation refers to an evaporation method in which a plurality of different substances are evaporated simultaneously from different evaporation sources. The hole transport layer 112 can be formed by evaporating a hole transport material.

[0586] The light-emitting layer 190 can be formed by evaporating a guest material that emits at least one of purple, blue, cyan, green, yellow-green, yellow, orange, and red. As the guest material, a light-emitting organic compound that emits fluorescence or phosphorescence can be used. In addition, it is preferred to use the structure of the light-emitting layer shown in Embodiment 1 and Embodiment 4. In addition, the light-emitting layer 190 may also have a double-layer structure. In this case, both light-emitting layers preferably have light-emitting substances that emit different colors from each other.

[0587] The electron-transporting layer 113 can be formed by evaporating a substance having a high electron-transporting property. Alternatively, the electron-injecting layer 114 can be formed by evaporating a substance having a high electron-injecting property.

[0588] The charge generation layer 115 can be formed by vapor deposition of a material in which an electron acceptor (acceptor) is added to a hole-transporting material or a material in which an electron donor (donor) is added to an electron-transporting material.

[0589] The Fifth Step

[0590] The fifth step is a step of forming the hole injection layer 116, the hole transport layer 117, the light emitting layer 170, the electron transport layer 118, the electron injection layer 119 and the electrode 102 (see Figure 8B ).

[0591] The hole injection layer 116 can be formed by using the same material and method as the hole injection layer 111 described above. In addition, the hole transport layer 117 can be formed by using the same material and method as the hole transport layer 112 described above.

[0592] The light-emitting layer 170 can be formed by evaporating a guest material that emits at least one light selected from purple, blue, cyan, green, yellow-green, yellow, orange, and red. A light-emitting organic compound that exhibits fluorescence or phosphorescence can be used as the guest material. In addition, the structure of the light-emitting layer described in Embodiment 1 and Embodiment 4 is preferably used. In addition, at least one of the light-emitting layer 170 and the light-emitting layer 190 preferably has the structure of the light-emitting layer described in Embodiment 1 and Embodiment 4. In addition, the light-emitting layer 170 and the light-emitting layer 190 preferably contain a light-emitting organic compound having a function of exhibiting light emission different from each other.

[0593] The electron-transport layer 118 can be formed using the same material and method as the electron-transport layer 113 described above. The electron-injection layer 119 can be formed using the same material and method as the electron-injection layer 114 described above.

[0594] The electrode 102 can be formed by stacking a reflective conductive film and a light-transmitting conductive film. The electrode 102 can have a single-layer structure or a stacked-layer structure.

[0595] Through the above steps, a light-emitting element is formed on the substrate 200 . The light-emitting element includes the region 222B, the region 222G, and the region 222R on the electrode 101 , the electrode 103 , and the electrode 104 , respectively.

[0596] Step Six

[0597] The sixth step is a process of forming a light shielding layer 223, an optical element 224B, an optical element 224G, and an optical element 224R on the substrate 220 (see Figure 8C ).

[0598] A resin film containing a black pigment is formed in a desired region to form the light shielding layer 223. Then, the optical element 224B, the optical element 224G, and the optical element 224R are formed on the substrate 220 and the light shielding layer 223. As the optical element 224B, a resin film containing a blue pigment is formed in a desired region. As the optical element 224G, a resin film containing a green pigment is formed in a desired region. As the optical element 224R, a resin film containing a red pigment is formed in a desired region.

[0599] The Seventh Step

[0600] The seventh step is a process of bonding the light emitting element formed on the substrate 200 to the light shielding layer 223 , the optical element 224B, the optical element 224G, and the optical element 224R formed on the substrate 220 , and sealing them with a sealant (not shown).

[0601] Through the above process, a Fig. 6A Light emitting element 262a is shown.

[0602] The structure described in this embodiment mode can be implemented in combination with the structures described in other embodiment modes as appropriate.

[0603] Implementation 7

[0604] In this embodiment, refer to 9A to 17B A display device according to one embodiment of the present invention will be described.

[0605] <Structural Example 1 of Display Device>

[0606] Fig.9A is a top view showing the display device 600, Fig. 9B is along Fig.9A The display device 600 is a cross-sectional view of the portion indicated by the dot-dash line AB and the dot-dash line CD. The display device 600 includes a driving circuit portion (a signal line driving circuit portion 601, a scanning line driving circuit portion 603) and a pixel portion 602. The signal line driving circuit portion 601, the scanning line driving circuit portion 603, and the pixel portion 602 have a function of controlling the light emission of the light emitting element.

[0607] The display device 600 further includes an element substrate 610 , a sealing substrate 604 , a sealant 605 , a region 607 surrounded by the sealant 605 , a routing wiring 608 , and an FPC 609 .

[0608] Note that the routing wiring 608 is a wiring for transmitting signals input to the signal line driver circuit portion 601 and the scanning line driver circuit portion 603 and receiving a video signal, a clock signal, a start signal, a reset signal, etc. from the FPC 609 used as an external input terminal. Note that although only the FPC 609 is shown here, the FPC 609 may be mounted with a printed wiring board (PWB).

[0609] As the signal line driver circuit portion 601, a CMOS circuit is formed by combining an N-channel transistor 623 and a P-channel transistor 624. In addition, various CMOS circuits, PMOS circuits, or NMOS circuits can be used as the signal line driver circuit portion 601 or the scan line driver circuit portion 603. In addition, although the display device in which a driver and pixels having a driver circuit portion are provided on the same surface of a substrate is shown in this embodiment, the driver circuit portion does not necessarily need to be formed on the substrate, and the driver circuit portion may be formed externally.

[0610] The pixel portion 602 includes a switching transistor 611, a current control transistor 612, and a lower electrode 613 electrically connected to the drain of the current control transistor 612. Note that a partition wall 614 is formed to cover an end of the lower electrode 613. As the partition wall 614, a positive photosensitive acrylic resin film can be used.

[0611] In order to obtain good coverage, the upper end or the lower end of the partition wall 614 is formed into a curved surface having a curvature. For example, when positive photosensitive acrylic is used as the material of the partition wall 614, it is preferred that only the upper end of the partition wall 614 includes a curved surface having a curvature (a curvature radius of 0.2 μm or more and 3 μm or less). As the partition wall 614, a negative photosensitive resin or a positive photosensitive resin can be used.

[0612] There is no particular restriction on the structure of the transistors (transistors 611, 612, 623, 624). For example, staggered transistors may also be used as transistors. In addition, there is no particular restriction on the polarity of the transistors, and a structure including an N-channel transistor and a P-channel transistor or a structure having only one of an N-channel transistor and a P-channel transistor may also be used. There is no particular restriction on the crystallinity of the semiconductor film used for the above-mentioned transistors. For example, an amorphous semiconductor film or a crystalline semiconductor film may be used. As semiconductor materials, Group 14 semiconductors (for example, semiconductors containing silicon), compound semiconductors (including oxide semiconductors), organic semiconductors, etc. may be used. As transistors, for example, oxide semiconductors having an energy gap of 2 eV or more, preferably 2.5 eV or more, and more preferably 3 eV or more are used, thereby reducing the off-state current of the transistor, so it is preferred. As the oxide semiconductor, for example, In-Ga oxide, In-M-Zn oxide (M represents aluminum (Al), gallium (Ga), yttrium (Y), zirconium (Zr), lanthanum (La), cerium (Ce), tin (Sn), hafnium (Hf) or neodymium (Nd)) and the like can be cited.

[0613] An EL layer 616 and an upper electrode 617 are formed over the lower electrode 613. Here, the lower electrode 613 is used as an anode, and the upper electrode 617 is used as a cathode.

[0614] The EL layer 616 is formed by various methods such as vapor deposition using a vapor deposition mask, inkjet, and spin coating. Other materials included in the EL layer 616 may be low molecular weight compounds or high molecular weight compounds (including oligomers and dendrimers).

[0615] A light-emitting element 618 is formed using the lower electrode 613, the EL layer 616, and the upper electrode 617. The light-emitting element 618 preferably has a structure described in Embodiment 1, Embodiment 4 to Embodiment 6. Note that when the pixel portion includes a plurality of light-emitting elements, the light-emitting elements described in Embodiment 1, Embodiment 4 to Embodiment 6 and light-emitting elements having other structures may be included.

[0616] In addition, by attaching the sealing substrate 604 to the element substrate 610 using the sealant 605, a structure is formed in which the light emitting element 618 is mounted in a region 607 surrounded by the element substrate 610, the sealing substrate 604, and the sealant 605. Note that the region 607 is filled with a filler. In addition to the case of filling with an inert gas (nitrogen or argon, etc.), there is also a case of filling with an ultraviolet curable resin or a thermosetting resin that can be used for the sealant 605. For example, PVC (polyvinyl chloride) resin, acrylic resin, polyimide resin, epoxy resin, silicone resin, PVB (polyvinyl butyral) resin, or EVA (ethylene vinyl acetate) resin can be used. By forming a concave portion in the sealing substrate and providing a desiccant therein, deterioration caused by moisture can be suppressed, which is preferred.

[0617] An optical element 621 is provided under the sealing substrate 604 so as to overlap with the light emitting element 618. A light shielding layer 622 is provided under the sealing substrate 604. The optical element 621 and the light shielding layer 622 may have the same structure as those described in Embodiment 6.

[0618] In addition, epoxy resin or glass powder is preferably used as the sealant 605. In addition, these materials are preferably materials that are as difficult to allow water or oxygen to pass through as possible. In addition, as a material for the sealing substrate 604, a glass substrate, a quartz substrate, or a plastic substrate composed of FRP (Fiber Reinforced Plastics; glass fiber reinforced plastics), PVF (polyvinyl fluoride), polyester, acrylic, etc. can be used.

[0619] Through the above steps, a display device including the light-emitting element and the optical element described in Embodiment Mode 1 and Embodiment Mode 4 to Embodiment Mode 6 can be obtained.

[0620] <Structural Example 2 of Display Device>

[0621] Below, refer to Fig. 10A and Fig. 10B and Fig.11 Other examples of display devices are described below. Fig. 10A and Fig. 10B and Fig.11 This is a cross-sectional view of a display device according to one embodiment of the present invention.

[0622] Fig. 10AShown are a substrate 1001, a base insulating film 1002, a gate insulating film 1003, gate electrodes 1006, 1007, 1008, a first interlayer insulating film 1020, a second interlayer insulating film 1021, a peripheral portion 1042, a pixel portion 1040, a driving circuit portion 1041, lower electrodes 1024R, 1024G, 1024B of the light-emitting element, a partition wall 1025, an EL layer 1028, an upper electrode 1026 of the light-emitting element, a sealing layer 1029, a sealing substrate 1031, a sealant 1032, and the like.

[0623] In addition, Fig. 10A In the embodiment, as an example of an optical element, a coloring layer (a red coloring layer 1034R, a green coloring layer 1034G, and a blue coloring layer 1034B) is provided on a transparent substrate 1033. In addition, a light shielding layer 1035 may be provided. The transparent substrate 1033 provided with the coloring layer and the light shielding layer is aligned and fixed to the substrate 1001. In addition, the coloring layer and the light shielding layer are covered by a covering layer 1036. In addition, Fig. 10A In the image, red light, green light, and blue light pass through the colored layer, so that an image can be presented with pixels of three colors.

[0624] Fig. 10B As an example of an optical element, a colored layer (red colored layer 1034R, green colored layer 1034G, blue colored layer 1034B) is formed between the gate insulating film 1003 and the first interlayer insulating film 1020. As described above, a colored layer may be provided between the substrate 1001 and the sealing substrate 1031.

[0625] exist Fig.11 , as an example of an optical element, a colored layer (red colored layer 1034R, green colored layer 1034G, blue colored layer 1034B) is formed between the first interlayer insulating film 1020 and the second interlayer insulating film 1021. In this way, a colored layer may be provided between the substrate 1001 and the sealing substrate 1031.

[0626] Although the above description describes a display device having a structure in which light is extracted from the substrate 1001 side where transistors are formed (bottom emission structure), a display device having a structure in which light is extracted from the sealing substrate 1031 (top emission structure) may also be used.

[0627] <Structural Example 3 of Display Device>

[0628] Fig. 12A and Fig. 12B An example of a cross-sectional view of a top emission type display device is shown. Fig. 12A and Fig. 12B is a cross-sectional view of a display device for explaining one embodiment of the present invention, and Fig. 10A and Fig. 10B and Fig.11 The driving circuit portion 1041, the peripheral portion 1042, etc. are shown.

[0629] In this case, a substrate that does not allow light to pass through can be used as the substrate 1001. The process until the connection electrode for connecting the transistor and the anode of the light-emitting element is manufactured is performed in the same manner as the bottom emission type display device. Then, a third interlayer insulating film 1037 is formed in a manner covering the electrode 1022. This insulating film may also have a planarization function. The third interlayer insulating film 1037 may be formed using the same material as the second interlayer insulating film or other various materials.

[0630] Although the lower electrodes 1024R, 1024G, and 1024B of the light-emitting element are used as anodes, they can also be used as cathodes. Fig. 12A and Fig. 12B In the case of a top emission type display device as shown, the lower electrodes 1024R, 1024G, and 1024B preferably have a function of reflecting light. In addition, an upper electrode 1026 is provided on the EL layer 1028. It is preferred that the upper electrode 1026 has a function of reflecting light and transmitting light, and a microcavity structure is adopted between the lower electrodes 1024R, 1024G, and 1024B and the upper electrode 1026 to enhance the intensity of light of a specific wavelength.

[0631] In adopting Fig. 12A In the case of the top emission structure shown, sealing can be performed using a sealing substrate 1031 provided with a coloring layer (a red coloring layer 1034R, a green coloring layer 1034G, and a blue coloring layer 1034B). The sealing substrate 1031 may also be provided with a light shielding layer 1035 located between pixels. In addition, as the sealing substrate 1031, a light-transmitting substrate is preferably used.

[0632] exist Fig. 12A In the embodiment, a structure in which a plurality of light emitting elements are provided and a coloring layer is provided on each of the plurality of light emitting elements is exemplified, but the present invention is not limited thereto. Fig. 12B As shown in FIG. 1 , a full-color display using three colors of red, green, and blue can be performed by providing a red coloring layer 1034R and a blue coloring layer 1034B without providing a green coloring layer. Fig. 12A As shown in FIG. 1 , when a coloring layer is provided for each light emitting element, the reflection of external light can be suppressed. Fig. 12B As shown, when a red coloring layer and a blue coloring layer are provided for a light emitting element but a green coloring layer is not provided, the energy loss of light emitted by the green light emitting element is small, thereby achieving the effect of reducing power consumption.

[0633] <Configuration Example 4 of Display Device>

[0634] Although the above-described display device includes sub-pixels of three colors (red, green, and blue), it may also include sub-pixels of four colors (red, green, blue, and yellow or red, green, blue, and white). FIG. 13A to FIG. 15B The structure of a display device including lower electrodes 1024R, 1024G, 1024B, and 1024Y is shown. Fig.13A , Fig. 13B and Fig.14 A display device having a structure (bottom emission type) in which light is extracted from a substrate 1001 on which transistors are formed is shown. Fig.15A and Fig. 15B A display device having a structure in which light is extracted from a sealing substrate 1031 (top emission type) is shown.

[0635] Fig.13A An example of a display device in which optical elements (coloring layer 1034R, coloring layer 1034G, coloring layer 1034B, coloring layer 1034Y) are provided on a transparent substrate 1033 is shown. Fig. 13B An example of a display device in which optical elements (coloring layer 1034R, coloring layer 1034G, coloring layer 1034B, coloring layer 1034Y) are formed between the first interlayer insulating film 1020 and the gate insulating film 1003 is shown. Fig.14 An example of a display device in which optical elements (a colored layer 1034R, a colored layer 1034G, a colored layer 1034B, and a colored layer 1034Y) are formed between a first interlayer insulating film 1020 and a second interlayer insulating film 1021 is shown.

[0636] The coloring layer 1034R has a function of transmitting red light, the coloring layer 1034G has a function of transmitting green light, and the coloring layer 1034B has a function of transmitting blue light. In addition, the coloring layer 1034Y has a function of transmitting yellow light or a function of transmitting a plurality of lights selected from blue, green, yellow, and red. When the coloring layer 1034Y has a function of transmitting a plurality of lights selected from blue, green, yellow, and red, the light emitted from the coloring layer 1034Y may also be white. The light-emitting element that emits yellow or white light has high light emission efficiency, so a display device including the coloring layer 1034Y can reduce power consumption.

[0637] In addition, Fig.15A and Fig. 15B In the top emission type display device shown in FIG. 1 , the light emitting element including the lower electrode 1024Y is also connected to the Fig. 12A The display device of the present invention also preferably has a microcavity structure between the lower electrode and the upper electrode 1026 and the lower electrodes 1024R, 1024G, 1024B, and 1024Y. Fig.15A In the display device, sealing can be performed using the sealing substrate 1031 provided with coloring layers (the red coloring layer 1034R, the green coloring layer 1034G, the blue coloring layer 1034B, and the yellow coloring layer 1034Y).

[0638] The light emitted through the microcavity and the yellow colored layer 1034Y is light having an emission spectrum in the yellow region. Since the visual sensitivity (luminosity factor) of yellow is high, the light emitting element emitting yellow light has high luminous efficiency. Fig.15A A display device with such a structure can reduce power consumption.

[0639] exist Fig.15A In the embodiment, a structure in which a plurality of light emitting elements are provided and a coloring layer is provided on each of the plurality of light emitting elements is exemplified, but the present invention is not limited thereto. Fig. 15B As shown, a red coloring layer 1034R, a green coloring layer 1034G, and a blue coloring layer 1034B may be provided without providing a yellow coloring layer, and full color display may be performed using four colors of red, green, blue, and yellow or four colors of red, green, blue, and white. Fig.15A As shown in FIG. 1 , when light-emitting elements are provided and a coloring layer is provided on each of the light-emitting elements, the effect of suppressing the reflection of external light is exerted. Fig. 15B As shown, when light-emitting elements and red, green and blue coloring layers are provided without providing a yellow coloring layer, energy loss of light emitted by the yellow or white light-emitting elements is small, thereby achieving the effect of reducing power consumption.

[0640] <Configuration Example 5 of Display Device>

[0641] then, Fig.16 A display device according to another embodiment of the present invention is shown. Fig.16 So Fig.9A The cross-sectional view cut by the dot-dash line AB and the dot-dash line CD. Fig.16 In, with Fig. 9B Parts having the same functions as those shown are denoted by the same reference numerals, and detailed description thereof may be omitted.

[0642] Fig.16The display device 600 shown includes a sealing layer 607a, a sealing layer 607b, and a sealing layer 607c in a region 607 surrounded by an element substrate 610, a sealing substrate 604, and a sealing agent 605. One or more of the sealing layers 607a, 607b, and 607c may use, for example, a resin such as PVC (polyvinyl chloride) resin, an acrylic resin, a polyimide resin, an epoxy resin, a silicone resin, a PVB (polyvinyl butyral) resin, or an EVA (ethylene-vinyl acetate) resin. In addition, inorganic materials such as silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, aluminum oxide, and aluminum nitride may be used. By forming the sealing layers 607a, 607b, and 607c, it is preferable to suppress the degradation of the light-emitting element 618 caused by impurities such as water. In addition, when the sealing layers 607a, 607b, and 607c are formed, the sealing agent 605 may not be provided.

[0643] In addition, one or two of the sealing layer 607a, the sealing layer 607b, and the sealing layer 607c may be formed, or four or more sealing layers may be formed. By making the sealing layer have multiple layers, it is possible to effectively prevent impurities such as water from entering the light-emitting element 618 inside the display device from the outside of the display device 600, so it is preferred. In addition, when the sealing layer has multiple layers, it is preferred that a resin and an inorganic material are stacked therein.

[0644] <Structural Example 6 of Display Device>

[0645] The display device described in Structural Examples 1 to 4 of this embodiment includes an optical element, but one embodiment of the present invention may not include an optical element.

[0646] Fig.17A and Fig. 17B The display device shown is a display device having a structure in which light is extracted from the sealing substrate 1031 side (a top emission type structure). Fig.17A This is an example of a display device including the light-emitting layer 1028R, the light-emitting layer 1028G, and the light-emitting layer 1028B. Fig. 17B This is an example of a display device including the light-emitting layer 1028R, the light-emitting layer 1028G, the light-emitting layer 1028B, and the light-emitting layer 1028Y.

[0647] The light-emitting layer 1028R emits red light, the light-emitting layer 1028G emits green light, and the light-emitting layer 1028B emits blue light. The light-emitting layer 1028Y has a function of emitting yellow light or a function of emitting a plurality of lights selected from blue, green, and red. The light emitted by the light-emitting layer 1028Y may also be white light. The light-emitting element emitting yellow or white light has high light emission efficiency, so a display device including the light-emitting layer 1028Y can reduce power consumption.

[0648] Fig.17A and Fig. 17B The display device shown includes EL layers that emit light of different colors in sub-pixels, thereby eliminating the need to provide a coloring layer used as an optical element.

[0649] The sealing layer 1029 may be made of, for example, PVC (polyvinyl chloride) resins, acrylic resins, polyimide resins, epoxy resins, silicone resins, PVB (polyvinyl butyral) resins, or EVA (ethylene vinyl acetate) resins. In addition, inorganic materials such as silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, aluminum oxide, and aluminum nitride may be used. By forming the sealing layer 1029, degradation of the light-emitting element caused by impurities such as water can be suppressed, so it is preferred.

[0650] In addition, the sealing layer 1029 may be formed as a single layer or a stacked layer, or may be formed as four or more sealing layers 1029. By making the sealing layer have multiple layers, it is possible to effectively prevent impurities such as water from entering the inside of the display device from the outside of the display device, so it is preferred. In addition, when the sealing layer is multi-layered, it is preferred that a resin and an inorganic material are stacked therein.

[0651] The sealing substrate 1031 only needs to have a function of protecting the light-emitting element. Therefore, the sealing substrate 1031 is a flexible substrate or a film.

[0652] The structure described in this embodiment mode can be combined with other structures in other embodiment modes or in this embodiment mode as appropriate.

[0653] Implementation 8

[0654] In this embodiment, refer to FIG. 18A to FIG. 20B A display device including a light-emitting element according to one embodiment of the present invention is described.

[0655] Notice, Fig.18A is a block diagram illustrating a display device according to one embodiment of the present invention. Fig.18B This is a circuit diagram for explaining a pixel circuit included in a display device according to one embodiment of the present invention.

[0656] <Description of Display Device>

[0657] Fig.18A The display device shown includes: a region having pixels of display elements (hereinafter referred to as a pixel portion 802); a circuit portion arranged outside the pixel portion 802 and having a circuit for driving the pixels (hereinafter referred to as a driving circuit portion 804); a circuit having a function of protecting the element (hereinafter referred to as a protection circuit 806); and a terminal portion 807. In addition, the protection circuit 806 may not be provided.

[0658] A part or all of the driver circuit portion 804 is preferably formed on the same substrate as the pixel portion 802. Thus, the number of components or the number of terminals can be reduced. When a part or all of the driver circuit portion 804 is not formed on the same substrate as the pixel portion 802, a part or all of the driver circuit portion 804 can be mounted by COG or TAB (Tape Automated Bonding).

[0659] The pixel portion 802 includes a circuit (hereinafter referred to as a pixel circuit 801) for driving a plurality of display elements arranged in X rows (X is a natural number greater than or equal to 2) and Y columns (Y is a natural number greater than or equal to 2), and the driving circuit portion 804 includes a circuit for outputting a signal (scanning signal) for selecting a pixel (hereinafter referred to as a scanning line driving circuit 804a) and a circuit for supplying a signal (data signal) for driving the display element of the pixel (hereinafter referred to as a signal line driving circuit 804b).

[0660] The scan line driving circuit 804a has a shift register and the like. The scan line driving circuit 804a is input with a signal for driving the shift register through the terminal portion 807 and outputs a signal. For example, the scan line driving circuit 804a is input with a start pulse signal, a clock signal and the like and outputs a pulse signal. The scan line driving circuit 804a has a function of controlling the potential of the wiring (hereinafter referred to as the scan line GL_1 to GL_X) to which the scan signal is supplied. In addition, a plurality of scan line driving circuits 804a may be provided, and the scan lines GL_1 to GL_X may be controlled respectively by the plurality of scan line driving circuits 804a. Alternatively, the scan line driving circuit 804a has a function of being able to supply an initialization signal. However, it is not limited thereto, and the scan line driving circuit 804a may also supply other signals.

[0661] The signal line driver circuit 804b has a shift register, etc. The signal line driver circuit 804b receives a signal for driving the shift register and a signal (video signal) for deriving a data signal therefrom through a terminal portion 807. The signal line driver circuit 804b has a function of generating a data signal written to the pixel circuit 801 according to the video signal. In addition, the signal line driver circuit 804b has a function of controlling the output of the data signal in response to a pulse signal generated by an input of a start pulse signal, a clock signal, etc. In addition, the signal line driver circuit 804b has a function of controlling the potential of the wiring (hereinafter referred to as data lines DL_1 to DL_Y) to which the data signal is supplied. Alternatively, the signal line driver circuit 804b has a function of being able to supply an initialization signal. However, it is not limited thereto, and the signal line driver circuit 804b can supply other signals.

[0662] The signal line driver circuit 804b is configured using, for example, a plurality of analog switches, etc. The signal line driver circuit 804b can output a signal obtained by time-dividing a video signal as a data signal by sequentially turning on the plurality of analog switches. The signal line driver circuit 804b may also include a shift register, etc.

[0663] The pulse signal and the data signal are input to each of the plurality of pixel circuits 801 through one of the plurality of scanning lines GL supplied with the scanning signal and one of the plurality of data lines DL supplied with the data signal, respectively. In addition, each of the plurality of pixel circuits 801 controls the writing and holding of the data signal through the scanning line driving circuit 804a. For example, a pulse signal is input from the scanning line driving circuit 804a to the pixel circuit 801 of the mth row and nth column through the scanning line GL_m (m is a natural number less than X), and a data signal is input from the signal line driving circuit 804b to the pixel circuit 801 of the mth row and nth column through the data line DL_n (n is a natural number less than Y) according to the potential of the scanning line GL_m.

[0664] Fig.18A The protection circuit 806 shown is connected to, for example, a scan line GL which is a wiring between the scan line driving circuit 804a and the pixel circuit 801. Alternatively, the protection circuit 806 is connected to a data line DL between the signal line driving circuit 804b and the pixel circuit 801. Alternatively, the protection circuit 806 may be connected to a wiring between the scan line driving circuit 804a and the terminal portion 807. Alternatively, the protection circuit 806 may be connected to a wiring between the signal line driving circuit 804b and the terminal portion 807. The terminal portion 807 refers to a portion provided with a terminal for inputting a power supply, a control signal, and a video signal from an external circuit to the display device.

[0665] The protection circuit 806 is a circuit that electrically connects a wiring connected thereto with another wiring when a potential outside a certain range is supplied to the wiring.

[0666] like Fig.18A As shown, by providing the pixel portion 802 and the driving circuit portion 804 with a protection circuit 806, respectively, the tolerance of the display device to overcurrents caused by ESD (Electro Static Discharge) and the like can be improved. However, the structure of the protection circuit 806 is not limited thereto, and for example, a structure in which the scanning line driving circuit 804a is connected to the protection circuit 806 or a structure in which the signal line driving circuit 804b is connected to the protection circuit 806 can also be adopted. Alternatively, a structure in which the terminal portion 807 is connected to the protection circuit 806 can also be adopted.

[0667] In addition, although Fig.18AThe example of forming the driver circuit portion 804 by the scan line driver circuit 804a and the signal line driver circuit 804b is shown in the figure, but the present invention is not limited to this. For example, only the scan line driver circuit 804a may be formed and a separately prepared substrate (for example, a driver circuit substrate formed of a single crystal semiconductor film or a polycrystalline semiconductor film) formed with a signal line driver circuit may be mounted.

[0668] <Configuration Example of Pixel Circuit>

[0669] Fig.18A The plurality of pixel circuits 801 shown may be, for example, Fig.18B The structure shown.

[0670] Fig.18B The pixel circuit 801 shown includes transistors 852 , 854 , a capacitor 862 , and a light emitting element 872 .

[0671] One of a source electrode and a drain electrode of the transistor 852 is electrically connected to a wiring (data line DL_n) to which a data signal is supplied, and a gate electrode of the transistor 852 is electrically connected to a wiring (scanning line GL_m) to which a gate signal is supplied.

[0672] The transistor 852 has a function of controlling writing of a data signal.

[0673] One of a pair of electrodes of the capacitor 862 is electrically connected to a wiring to which a potential is supplied (hereinafter referred to as a potential supply line VL_a), and the other is electrically connected to the other of a source electrode and a drain electrode of the transistor 852 .

[0674] The capacitor 862 functions as a storage capacitor for storing written data.

[0675] One of a source electrode and a drain electrode of the transistor 854 is electrically connected to the potential supply line VL_a, and a gate electrode of the transistor 854 is electrically connected to the other of a source electrode and a drain electrode of the transistor 852 .

[0676] One of the anode and the cathode of the light-emitting element 872 is electrically connected to the potential supply line VL_b, and the other is electrically connected to the other of the source electrode and the drain electrode of the transistor 854 .

[0677] As the light-emitting element 872, the light-emitting element described in Embodiment 1 or Embodiment 4 to Embodiment 6 can be used.

[0678] Furthermore, the high power supply potential VDD is applied to one of the potential supply line VL_a and the potential supply line VL_b, and the low power supply potential VSS is applied to the other.

[0679] For example, in a Fig.18B In the display device of the pixel circuit 801, by Fig.18A The scan line driving circuit 804a shown selects the pixel circuits 801 in each row in sequence, and turns on the transistors 852 to write the data of the data signal.

[0680] When the transistor 852 is turned off, the pixel circuit 801 in which the data is written is in a hold state. Furthermore, the amount of current flowing between the source electrode and the drain electrode of the transistor 854 is controlled according to the potential of the written data signal, and the light-emitting element 872 emits light at a brightness corresponding to the amount of current flowing. By sequentially performing the above steps row by row, an image can be displayed.

[0681] In addition, the pixel circuit can be provided with a function of correcting a variation in the threshold voltage of a transistor or the like. Fig.19A and Fig.19B and Fig. 20A and Fig. 20B An example of a pixel circuit is shown.

[0682] Fig.19A The pixel circuit shown includes six transistors (transistors 303_1 to 303_6), a capacitor 304, and a light emitting element 305. In addition, wirings 301_1 to 301_5, wiring 302_1, and wiring 302_2 are electrically connected to Fig.19A Note that as the transistors 303_1 to 303_6, for example, p-channel transistors can be used.

[0683] Fig.19B The pixel circuit shown is a Fig.19A The pixel circuit shown in the figure has a structure in which a transistor 303_7 is added. In addition, wiring 301_6 and wiring 301_7 are electrically connected to Fig.19B Here, the wiring 301_5 and the wiring 301_6 may be electrically connected to each other. Note that as the transistor 303_7, for example, a p-channel transistor can be used.

[0684] Fig. 20A The pixel circuit shown includes six transistors (transistors 308_1 to 308_6), a capacitor 304, and a light emitting element 305. In addition, wirings 306_1 to 306_3 and wirings 307_1 to 307_3 are electrically connected to Fig. 20A Here, the wiring 306_1 and the wiring 306_3 may be electrically connected to each other. Note that as the transistors 308_1 to 308_6, for example, p-channel transistors can be used.

[0685] Fig. 20BThe pixel circuit shown includes two transistors (transistor 309_1 and transistor 309_2), two capacitors (capacitor 304_1 and capacitor 304_2), and a light emitting element 305. In addition, wiring 311_1 to wiring 311_3, wiring 312_1, and wiring 312_2 are electrically connected to Fig. 20B In addition, by using Fig. 20B The pixel circuit shown in the structure can be driven by, for example, a voltage input-current driving method (also referred to as a CVCC method) Note that, as the transistors 309_1 and 309_2, for example, p-channel transistors can be used.

[0686] Furthermore, the light-emitting element of one embodiment of the present invention can be applied to an active matrix method in which an active element is included in a pixel of a display device, or a passive matrix method in which an active element is not included in a pixel of a display device.

[0687] In the active matrix method, various active elements (non-linear elements) can be used as active elements (non-linear elements) in addition to transistors. For example, MIM (Metal Insulator Metal) or TFD (Thin Film Diode) can also be used. Since these elements have fewer manufacturing steps, the manufacturing cost can be reduced or the yield rate can be improved. In addition, since the size of these elements is small, the aperture ratio can be increased, thereby achieving low power consumption or high brightness.

[0688] As a method other than the active matrix method, a passive matrix type that does not use active elements (non-linear elements) can also be adopted. Since active elements (non-linear elements) are not used, the manufacturing process is small, thereby reducing manufacturing costs or improving yields. In addition, since active elements (non-linear elements) are not used, the aperture ratio can be increased, thereby achieving low power consumption or high brightness, etc.

[0689] The structure described in this embodiment mode can be implemented in combination with the structures described in other embodiment modes as appropriate.

[0690] Implementation method 9

[0691] In this embodiment, refer to FIG. 21A to FIG. 25 A display device including a light-emitting element according to one embodiment of the present invention and an electronic device in which an input device is mounted on the display device are described.

[0692] <Notes on touch panel 1>

[0693] Note that in this embodiment, as an example of an electronic device, the touch panel 2000 including a display device and an input device is described. Also, as an example of the input device, a case where a touch sensor is included is described.

[0694] Fig.21A and Fig. 21B is a perspective view of touch panel 2000. Fig.21A and Fig. 21B In FIG. 2 , for the sake of clarity, only typical components of touch panel 2000 are shown.

[0695] The touch panel 2000 includes a display device 2501 and a touch sensor 2595 (see Fig. 21B ). In addition, the touch panel 2000 further includes a substrate 2510, a substrate 2570, and a substrate 2590. In addition, the substrate 2510, the substrate 2570, and the substrate 2590 are all flexible. Note that any one or all of the substrate 2510, the substrate 2570, and the substrate 2590 may not be flexible.

[0696] The display device 2501 includes a plurality of pixels on a substrate 2510 and a plurality of wirings 2511 for supplying signals to the pixels. The plurality of wirings 2511 are guided to the periphery of the substrate 2510, and a portion thereof constitutes a terminal 2519. The terminal 2519 is electrically connected to the FPC 2509 (1). In addition, the plurality of wirings 2511 can supply signals from the signal line driver circuit 2503s (1) to the plurality of pixels.

[0697] The substrate 2590 includes a touch sensor 2595 and a plurality of wirings 2598 electrically connected to the touch sensor 2595. The plurality of wirings 2598 are guided to the outer periphery of the substrate 2590, and a portion of the wirings 2598 constitutes a terminal. The terminal is electrically connected to the FPC 2509 (2). Fig. 21B In the figure, electrodes, wiring, etc. of the touch sensor 2595 provided on the back side of the substrate 2590 (the side opposite to the substrate 2510) are shown by solid lines.

[0698] For example, a capacitive touch sensor can be applied as the touch sensor 2595. Examples of the capacitive touch sensor include a surface capacitive touch sensor and a projection capacitive touch sensor.

[0699] As a projected capacitive touch sensor, it is mainly divided into a self-capacitive touch sensor, a mutual-capacitive touch sensor, etc. according to the difference in driving method. When a mutual-capacitive touch sensor is used, it can detect multiple points at the same time, so it is preferable.

[0700] Notice, Fig. 21BThe touch sensor 2595 shown is a structure that uses a projected capacitive touch sensor.

[0701] In addition, various sensors that can detect the approach or contact of a detection object such as a finger can be applied as the touch sensor 2595.

[0702] The projected capacitive touch sensor 2595 includes an electrode 2591 and an electrode 2592. The electrode 2591 is electrically connected to any one of a plurality of wirings 2598, and the electrode 2592 is electrically connected to any other one of the plurality of wirings 2598.

[0703] like Fig.21A and Fig. 21B As shown, the electrodes 2592 have a shape in which a plurality of quadrilaterals arranged in one direction are connected to each other at their corners.

[0704] The electrodes 2591 are all quadrilateral and are repeatedly arranged in a direction intersecting the direction in which the electrodes 2592 extend.

[0705] The wiring 2594 is electrically connected to the two electrodes 2591 sandwiching the electrode 2592. At this time, the intersection area of ​​the electrode 2592 and the wiring 2594 is preferably as small as possible. As a result, the area of ​​the region where no electrode is provided can be reduced, thereby reducing the deviation of the transmittance. As a result, the brightness deviation of the light passing through the touch sensor 2595 can be reduced.

[0706] Note that the shapes of the electrodes 2591 and 2592 are not limited thereto, and may have various shapes. For example, the following structure may be adopted: a plurality of electrodes 2591 are arranged with as little gap therebetween as possible, and a plurality of electrodes 2592 are arranged spaced apart via an insulating layer to form a region that does not overlap the electrodes 2591. In this case, by providing a virtual electrode electrically insulated from these electrodes between two adjacent electrodes 2592, the area of ​​the region with different transmittances can be reduced, which is preferred.

[0707] <Description of Display Device>

[0708] Next, refer to Fig.22A The details of the display device 2501 will be described. Fig.22A is along Fig. 21B A cross-sectional view of the portion indicated by the dashed line X1-X2.

[0709] The display device 2501 includes a plurality of pixels arranged in a matrix, each of which includes a display element and a pixel circuit for driving the display element.

[0710] In the following description, an example is described in which a light-emitting element emitting white light is used as a display element, but the display element is not limited to this. For example, light-emitting elements emitting different colors of light may be included so that the colors of light emitted from adjacent pixels are different.

[0711] As the substrate 2510 and the substrate 2570, for example, a substrate having a water vapor transmission rate of 1×10 -5 g·m -2 ·day -1 Below, preferably 1×10 -6 g·m -2 ·day -1 Alternatively, it is preferable to use materials having substantially the same thermal expansion coefficient for the substrate 2510 and the substrate 2570. For example, the linear expansion coefficient is preferably 1×10 -3 / K or less, more preferably 5×10 -5 / K or less, more preferably 1×10 -5 / K or less.

[0712] Note that the substrate 2510 is a laminate including an insulating layer 2510a for preventing impurities from diffusing into the light-emitting element, a flexible substrate 2510b, and an adhesive layer 2510c for bonding the insulating layer 2510a and the flexible substrate 2510b. Also, the substrate 2570 is a laminate including an insulating layer 2570a for preventing impurities from diffusing into the light-emitting element, a flexible substrate 2570b, and an adhesive layer 2570c for bonding the insulating layer 2570a and the flexible substrate 2570b.

[0713] Adhesive layer 2510c and adhesive layer 2570c may be made of, for example, polyester, polyolefin, polyamide (nylon, aramid, etc.), polyimide, polycarbonate, acrylic resin, polyurethane, epoxy resin, or a material containing a resin having a siloxane bond such as silicone.

[0714] In addition, a sealing layer 2560 is included between the substrate 2510 and the substrate 2570. The sealing layer 2560 preferably has a refractive index greater than that of air. Fig.22A As shown, when light is extracted through the sealing layer 2560, the sealing layer 2560 can also serve as an optical bonding layer.

[0715] In addition, a sealant can be formed on the periphery of the sealing layer 2560. By using the sealant, the light-emitting element 2550R can be arranged in the area surrounded by the substrate 2510, the substrate 2570, the sealing layer 2560 and the sealant. Note that as the sealing layer 2560, an inert gas (nitrogen or argon, etc.) can be filled. In addition, a desiccant can be set in the inert gas to absorb moisture, etc. Alternatively, a resin such as an acrylic resin or an epoxy resin can be used. In addition, as the above-mentioned sealant, for example, an epoxy resin or glass powder is preferably used. In addition, as a material for the sealant, it is preferable to use a material that does not allow moisture or oxygen to pass through.

[0716] In addition, the display device 2501 includes a pixel 2502R. In addition, the pixel 2502R includes a light emitting module 2580R.

[0717] The pixel 2502R includes a light-emitting element 2550R and a transistor 2502t that can supply power to the light-emitting element 2550R. Note that the transistor 2502t is used as a part of the pixel circuit. In addition, the light-emitting module 2580R includes the light-emitting element 2550R and a coloring layer 2567R.

[0718] The light-emitting element 2550R includes a lower electrode, an upper electrode, and an EL layer between the lower electrode and the upper electrode. As the light-emitting element 2550R, for example, the light-emitting element described in Embodiment 1 or Embodiment 4 to Embodiment 6 can be used.

[0719] In addition, a microcavity structure may be used between the lower electrode and the upper electrode to enhance the intensity of light of a specific wavelength.

[0720] In addition, when the sealing layer 2560 is provided on the light extraction side, the sealing layer 2560 is in contact with the light emitting element 2550R and the coloring layer 2567R.

[0721] The coloring layer 2567R is located at a position overlapping the light emitting element 2550R. Therefore, part of the light emitted from the light emitting element 2550R passes through the coloring layer 2567R and is emitted to the outside of the light emitting module 2580R in the direction indicated by the arrow in the drawing.

[0722] In addition, in the display device 2501, a light shielding layer 2567BM is provided in the direction of emitting light. The light shielding layer 2567BM is provided in a manner surrounding the color layer 2567R.

[0723] The coloring layer 2567R only needs to have a function of transmitting light in a specific wavelength region, and for example, a color filter that transmits light in a red wavelength region, a color filter that transmits light in a green wavelength region, a color filter that transmits light in a blue wavelength region, and a color filter that transmits light in a yellow wavelength region can be used. Each color filter can be formed using various materials by printing, inkjet, etching using photolithography technology, and the like.

[0724] In addition, the display device 2501 is provided with an insulating layer 2521. The insulating layer 2521 covers the transistor 2502t. In addition, the insulating layer 2521 has a function of covering the unevenness caused by the pixel circuit. In addition, the insulating layer 2521 can have a function of suppressing the diffusion of impurities. Thus, the reliability of the transistor 2502t and the like can be suppressed from being reduced due to the diffusion of impurities.

[0725] The light-emitting element 2550R is formed over the insulating layer 2521. The partition wall 2528 is provided so as to overlap with an end portion of a lower electrode included in the light-emitting element 2550R. A spacer for controlling the interval between the substrate 2510 and the substrate 2570 may be formed over the partition wall 2528.

[0726] The scan line driver circuit 2503g(1) includes a transistor 2503t and a capacitor 2503c. Note that the driver circuit and the pixel circuit can be formed over the same substrate by the same process.

[0727] In addition, wiring 2511 capable of supplying signals is provided on the substrate 2510. In addition, a terminal 2519 is provided on the wiring 2511. In addition, FPC 2509 (1) is electrically connected to the terminal 2519. In addition, FPC 2509 (1) has a function of supplying a video signal, a clock signal, a start signal, a reset signal, etc. In addition, a printed wiring board (PWB) may be mounted on FPC 2509 (1).

[0728] In addition, transistors of various structures can be applied to the display device 2501. Fig.22A Although the bottom-gate transistor is shown in FIG. 1 , it is not limited to this. For example, Fig. 22B The top-gate transistor shown is suitable for the display device 2501.

[0729] In addition, there is no particular restriction on the polarity of transistor 2502t and transistor 2503t. For example, n-channel transistors and p-channel transistors can be used, or n-channel transistors or p-channel transistors can be used. In addition, there is no particular restriction on the crystallinity of the semiconductor film used for transistors 2502t and 2503t. For example, an amorphous semiconductor film or a crystalline semiconductor film can be used. In addition, as a semiconductor material, a Group 14 semiconductor (for example, a semiconductor containing silicon), a compound semiconductor (including an oxide semiconductor), an organic semiconductor, etc. can be used. By using an oxide semiconductor with an energy gap of 2eV or more, preferably 2.5eV or more, and more preferably 3eV or more for any one or both of transistors 2502t and transistor 2503t, the off-s...

Claims

1. A light emitting device, comprising: A light-emitting layer between a pair of electrodes, The light-emitting layer comprises a first organic compound, a second organic compound, and a guest material. wherein the first organic compound is a heterocyclic compound containing a triazine skeleton, a pyrimidine skeleton, a pyridazine skeleton or a pyridine skeleton, wherein the LUMO energy level of the first organic compound is lower than the LUMO energy level of the second organic compound, wherein the HOMO energy level of the first organic compound is lower than the HOMO energy level of the second organic compound, wherein the guest material converts triplet excitation energy into luminescence, wherein the first organic compound and the second organic compound form an exciplex, wherein an energy difference between the LUMO energy level of the guest material and the HOMO energy level of the guest material is greater than an energy difference between the LUMO energy level of the first organic compound and the HOMO energy level of the second organic compound, wherein the energy difference between the LUMO energy level of the guest material and the LUMO energy level of the first organic compound is greater than or equal to 0.2 eV, and The energy difference between the LUMO energy level of the first organic compound and the HOMO energy level of the second organic compound is greater than or equal to the migration energy obtained from the absorption end of the guest material.

2. The light emitting device according to claim 1, in, The LUMO energy level of the guest material is higher than the LUMO energy level of the first organic compound, and The HOMO energy level of the guest material is lower than the HOMO energy level of the second organic compound.

3. The light emitting device according to claim 1, wherein: The emission spectrum of the guest material has at least one peak in a wavelength region of 400 nm to less than 505 nm.

4. The light emitting device according to claim 1, wherein: The HOMO energy level of the guest material is higher than the HOMO energy level of the first organic compound.

5. The light emitting device according to claim 1, in, The guest material comprises a ligand coordinated to iridium, and Wherein, the ligand comprises a nitrogen-containing five-membered heterocyclic skeleton and a cyano group.

6. The light emitting device according to claim 5, wherein: The nitrogen-containing five-membered heterocyclic skeleton is a triazole skeleton.

7. The light emitting device according to claim 1, in, The second organic compound includes at least one of a π-electron-rich aromatic heterocyclic skeleton and an aromatic amine skeleton.

8. The light emitting device according to claim 1, in, An energy difference between a LUMO energy level of the guest material and a HOMO energy level of the guest material is greater than a transition energy obtained from an absorption end of the guest material by more than 0.4 eV.

9. A light emitting device, comprising: A light-emitting layer between a pair of electrodes, The light-emitting layer comprises a first organic compound, a second organic compound, and a guest material as a phosphorescent compound. wherein the first organic compound is a heterocyclic compound containing a triazine skeleton, a pyrimidine skeleton, a pyridazine skeleton or a pyridine skeleton, wherein the second organic compound is a carbazole derivative, wherein the LUMO energy level of the first organic compound is lower than the LUMO energy level of the second organic compound, wherein the HOMO energy level of the first organic compound is lower than the HOMO energy level of the second organic compound, wherein the guest material converts triplet excitation energy into luminescence, wherein the first organic compound and the second organic compound form an exciplex, wherein an energy difference between the LUMO energy level of the guest material and the HOMO energy level of the guest material is greater than an energy difference between the LUMO energy level of the first organic compound and the HOMO energy level of the second organic compound, wherein the energy difference between the LUMO energy level of the guest material and the LUMO energy level of the first organic compound is greater than or equal to 0.2 eV, and The energy difference between the HOMO energy level of the guest material and the HOMO energy level of the second organic compound is greater than or equal to 0.1 eV.

10. The light emitting device according to claim 9, in, The LUMO energy level of the guest material is higher than the LUMO energy level of the first organic compound, and The HOMO energy level of the guest material is lower than the HOMO energy level of the second organic compound.

11. The light emitting device according to claim 9, wherein: The emission spectrum of the guest material has at least one peak in a wavelength region of 400 nm to less than 505 nm.

12. The light emitting device according to claim 9, wherein: The HOMO energy level of the guest material is higher than the HOMO energy level of the first organic compound.

13. The light emitting device according to claim 9, in, The guest material comprises a ligand coordinated to iridium, and Wherein, the ligand comprises a nitrogen-containing five-membered heterocyclic skeleton and a cyano group.

14. The light emitting device according to claim 13, wherein: The nitrogen-containing five-membered heterocyclic skeleton is a triazole skeleton.

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