Light-emitting element, organic compound, light-emitting device, electronic device, and lighting device

Abstract

Provided are a novel compound and a light-emitting element with high emission efficiency and long element lifetime. The novel compound has a benzo-furo[3,2-d]pyrazine skeleton or a benzo-thiopheno[3,2-d]pyrazine skeleton, and the benzene ring and the pyrazine ring in the benzo-furo[3,2-d]pyrazine skeleton or the benzo-thiopheno[3,2-d]pyrazine skeleton each independently has a substituent with a total of 6 to 100 carbon atoms. A light-emitting element includes the compound.

Description

[0001] This application is a divisional application of the patent application with application number 201780077212.1 (PCT / IB2017 / 057977), filed on December 15, 2017, and titled "Light-emitting Element, Organic Compound, Light-emitting Device, Electronic Device, and Lighting Device". TECHNICAL FIELD

[0002] One embodiment of the present application relates to a light-emitting element including a benzo-furo[3,2-g]pyrazine compound or a benzo-thiopheno[3,2-g]pyrazine compound. One embodiment of the present application relates to a novel organic compound. One embodiment of the present application relates to a benzo-furo[3,2-g]pyrazine compound or a benzo-thiopheno[3,2-g]pyrazine compound. One embodiment of the present application relates to a light-emitting device, an electronic device, and a lighting device each including the above-described organic compound.

[0003] Note that one embodiment of the present application is not limited to the technical field described above. One embodiment of the present application relates to an object, a method, or a manufacturing method. In addition, one embodiment of the present application relates to a process, a machine, manufacture, or a composition of matter. In particular, one embodiment of the present application relates to a semiconductor device, a light-emitting device, a display device, a lighting device, a light-emitting element, or a manufacturing method thereof. Furthermore, one embodiment of the present application relates to a novel synthetic method of a benzo-furo[3,2-g]pyrazine compound or a benzo-thiopheno[3,2-g]pyrazine compound including a π-electron-rich aromatic heterocycle. Thus, specific examples of one embodiment of the present application disclosed in this specification are a light-emitting element, a light-emitting device, an electronic device, and a lighting device each including the organic compound, and a manufacturing method thereof. BACKGROUND

[0004] Utilization of a light-emitting element including an organic compound and utilizing electroluminescence (EL) is very active. In a basic structure of such a light-emitting element, an organic compound layer containing a light-emitting material (an electroluminescent (EL) layer) is provided between a pair of electrodes. By applying voltage to this element, carriers are injected, and light emission can be obtained from the light-emitting material by using recombination energy of the carriers.

[0005] Since such a light-emitting element is a self-luminous light-emitting element, it has an advantage of higher visibility when used for a pixel of a display, and does not need a backlight or the like. Thus, the light-emitting element is suitable for a flat panel display element. In addition, a display using such a light-emitting element can be manufactured to be thin and light, which is also a great advantage. Furthermore, a very high response speed is one of characteristics of the light-emitting element.

[0006] In such a light-emitting element, a light-emitting layer can be formed in a two-dimensional manner, and thus planar emission can be obtained. This is a feature that is difficult to obtain in a point light source typified by an incandescent lamp or an LED or a linear light source typified by a fluorescent lamp. In addition, the light emission of an organic compound can be made to be light emission that does not contain ultraviolet light by selecting a material, and thus the light-emitting element is also highly useful as a surface light source that can be applied to illumination and the like.

[0007] As described above, although displays or lighting devices including a light-emitting element are applied to a variety of electronic devices, research and development of a light-emitting element with higher efficiency and longer element lifetime are increasingly active. In particular, since an EL layer mainly uses an organic compound, the organic compound has a large influence on improvement of element characteristics of a light-emitting element. Thus, a variety of novel organic compounds have been developed.

[0008] The lifetime and characteristics of a light-emitting element including an organic compound are sometimes greatly influenced by the characteristics of a host material and a hole-transport material.

[0009] A substance having various skeletons is used as a host material. Among them, a diazine skeleton has a high triplet excitation energy level, and thus various compounds including a diazine skeleton have been reported. Although the characteristics and reliability of a light-emitting element using these compounds have been improved, they are not sufficient to meet various high-standard characteristics such as efficiency and durability (for example, Patent Document 1 and Patent Document 2).

[0010] [REFERENCE]

[0011] [REFERENCE]

[0012] [Patent Document 1] Japanese Patent Application Publication No. 2014-209611

[0013] [Patent Document 2] Japanese PCT International Application Publication No. 2013-536196 SUMMARY

[0014] In view of the above problems, an object of one embodiment of the present application is to provide a novel organic compound. In particular, an object of one embodiment of the present application is to provide a novel benzofuro[3,2-g]pyrazine compound or a benzothieno[3,2-g]pyrazine compound. Another object of one embodiment of the present application is to provide a novel organic compound having electron-transport properties. Another object of one embodiment of the present application is to provide a light-emitting element with high reliability. Another object of one embodiment of the present application is to provide a light-emitting element with high emission efficiency. Another object of one embodiment of the present application is to provide a light-emitting element with low driving voltage.

[0015] Another object of one embodiment of the present application is to provide a light-emitting element, a light-emitting device, and an electronic device each of which has high reliability. Another object of one embodiment of the present application is to provide a light-emitting element, a light-emitting device, and an electronic device each of which has low power consumption.

[0016] Note that the description of these objects does not preclude the existence of other objects. In one embodiment of the present application, all the above objects are not required to be achieved. An object other than the above can be extracted from the description, drawings, claims, and the like.

[0017] One embodiment of the present application is a light-emitting element including an EL layer between a pair of electrodes. The EL layer includes a substance having a benzo-furo[3,2-g]pyrazine skeleton or a benzo-thiopheno[3,2-g]pyrazine skeleton. A benzene ring in the benzo-furo[3,2-g]pyrazine skeleton or the benzo-thiopheno[3,2-g]pyrazine skeleton has a first substituent with a total number of carbon atoms of 6 to 100. A pyrazine ring in the benzo-furo[3,2-g]pyrazine skeleton or the benzo-thiopheno[3,2-g]pyrazine skeleton has a second substituent with a total number of carbon atoms of 6 to 100.

[0018] Another embodiment of the present application is a light-emitting element including an EL layer between a pair of electrodes. The EL layer includes a substance having a benzo-furo[3,2-g]pyrazine skeleton or a benzo-thiopheno[3,2-g]pyrazine skeleton. A benzene ring in the benzo-furo[3,2-g]pyrazine skeleton or the benzo-thiopheno[3,2-g]pyrazine skeleton has a first substituent with a total number of carbon atoms of 10 to 100. A pyrazine ring in the benzo-furo[3,2-g]pyrazine skeleton or the benzo-thiopheno[3,2-g]pyrazine skeleton has a second substituent with a total number of carbon atoms of 10 to 100. At this time, it is preferable that the first substituent and the second substituent each independently have an aromatic ring with a number of carbon atoms of 10 to 30 or an aromatic heterocycle with a number of carbon atoms of 10 to 30.

[0019] In the above structure, it is preferable that the first substituent and the second substituent each independently have at least one of a substituted or unsubstituted benzene ring, a substituted or unsubstituted naphthalene ring, a substituted or unsubstituted phenanthrene ring, a substituted or unsubstituted triphenylene ring, a substituted or unsubstituted condensed aromatic heterocycle with a number of carbon atoms of 12 to 30, and a substituted or unsubstituted triarylamine structure, and it is preferable that the condensed aromatic heterocycle include any of a dibenzofuran ring, a dibenzothiophene ring, and a carbazole ring.

[0020] In the above structure, it is preferable that the second substituent have a hole-transport skeleton. The hole-transport skeleton preferably has a triarylamine structure or a π-electron rich aromatic heterocycle. The hole-transport skeleton is particularly preferably a condensed aromatic heterocycle including any of a carbazole ring, a dibenzofuran ring, and a dibenzothiophene ring.

[0021] It is preferable that the EL layer include a light-emitting layer, and the light-emitting layer contain the above-described substance having a benzo furanopyrazine skeleton or a benzo thienopyrazine skeleton and a substance capable of converting a triplet excitation energy into light emission. This structure is particularly effective in the case where the substance capable of converting the triplet excitation energy into light emission is a phosphorescent compound.

[0022] Another embodiment of the present application is an organic compound represented by the following General Formula (G0).

[0023]

[0024] In General Formula (G0), X represents oxygen or sulfur, A 1 and A 2 each independently represent a substituent having a carbon atom number of 6 to 100. R 1 to R 4 each independently represent hydrogen, an alkyl group having a carbon atom number of 1 to 6, a substituted or unsubstituted cycloalkyl group having a carbon atom number of 3 to 7, or a substituted or unsubstituted aryl group having a carbon atom number of 6 to 25.

[0025] In General Formula (G0), it is preferable that A 1 and A 2 each independently represent a substituent having a carbon atom number of 10 to 100. At this time, it is preferable that A 1 and A 2 each independently have an aromatic ring having a carbon atom number of 10 to 30 or an aromatic heterocyclic ring having a carbon atom number of 10 to 30.

[0026] In the compound represented by General Formula (G0) above, it is more preferable that A 1 and A 2 each independently have at least one of a substituted or unsubstituted benzene ring, a substituted or unsubstituted naphthalene ring, a substituted or unsubstituted phenanthrene ring, a substituted or unsubstituted triphenylene ring, a substituted or unsubstituted condensed aromatic heterocyclic ring having a carbon atom number of 12 to 30, and a substituted or unsubstituted triphenylamine structure. It is preferable that the condensed aromatic heterocyclic ring have any one of a dibenzofuran ring, a dibenzothiophene ring, and a carbazole ring.

[0027] In the above structure, it is preferable that A 2 have a condensed aromatic heterocyclic ring including any one of a carbazole ring, a dibenzofuran ring, and a dibenzothiophene ring.

[0028] Another embodiment of the present application is an organic compound represented by the following General Formula (G1).

[0029]

[0030] In General Formula (G1), X represents oxygen or sulfur, A 1 represents a substituent having a total carbon atom number of 6 to 100. Ht2 represents a substituted or unsubstituted aromatic ring having 10 to 30 carbon atoms or a substituted or unsubstituted heteroaromatic ring having 10 to 30 carbon atoms. Ar 2 represents a substituted or unsubstituted arylene group having 6 to 25 carbon atoms, R 1 to R 4 each independently represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 25 carbon atoms. m represents an integer of 0 to 3.

[0031] In the above structure, preferably, Ht 1 is a substituent having a total of 10 to 100 carbon atoms.

[0032] Preferably, Ht 2 is a substituted or unsubstituted condensed aromatic hetero ring including any one of a carbazole ring, a dibenzofuran ring, and a dibenzothiophene ring.

[0033] Another embodiment of the present application is an organic compound represented by the following General Formula (G2).

[0034]

[0035] In General Formula (G2), X represents oxygen or sulfur, Ht 1 and Ht 2 each independently represents an aromatic ring having 10 to 30 carbon atoms or a heteroaromatic ring having 10 to 30 carbon atoms. Ar 1 and Ar 2 each independently represents a substituted or unsubstituted arylene group having 6 to 25 carbon atoms, R 1 to R 4 each independently represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 25 carbon atoms. n and m each independently represents an integer of 0 to 3.

[0036] In the above structure, preferably, Ht 1 and Ht 2 each independently represents a substituted or unsubstituted condensed aromatic hetero ring including any one of a carbazole ring, a dibenzofuran ring, and a dibenzothiophene ring.

[0037] In the above structure, preferably, Ar 1 or Ar 2 is a substituted or unsubstituted phenylene group, and preferably, R 1 to R 4 are all hydrogen.

[0038] Another embodiment of the present application is an organic compound represented by the following General Formula (G3).

[0039]

[0040] In General Formula (G3), X represents oxygen or sulfur, A 1 represents a substituted or unsubstituted aromatic heterocycle including any one of a carbazole ring, a dibenzofuran ring, and a dibenzothiophene ring. Ht 2 represents a substituted or unsubstituted aromatic heterocycle including any one of a carbazole ring, a dibenzofuran ring, and a dibenzothiophene ring.

[0041] Another embodiment of the present application is an organic compound represented by General Formula (G4) below.

[0042]

[0043] In General Formula (G4), X represents oxygen or sulfur. Ht 1 and Ht 2 respectively independently represent any one of a substituted or unsubstituted aromatic heterocycle including any one of a carbazole ring, a dibenzofuran ring, and a dibenzothiophene ring.

[0044] In the above structure, Ht 1 and Ht 2 respectively independently represent any one of groups represented by General Formulae (Ht-1) to (Ht-7) below.

[0045]

[0046] In General Formulae (Ht-1) to (Ht-7), R 10 to R 22 respectively independently represent any one of hydrogen, an alkyl group having a carbon atom number of 1 to 6, a substituted or unsubstituted cycloalkyl group having a carbon atom number of 3 to 7, and a substituted or unsubstituted aryl group having a carbon atom number of 6 to 25.

[0047] Another embodiment of the present application is an organic compound represented by General Formula (G5) below.

[0048]

[0049] In General Formula (G5), X represents oxygen or sulfur, Z 1 and Z 2 respectively independently represent oxygen or sulfur.

[0050] Another embodiment of the present application is an organic compound represented by Structural Formula (100) or (101) below.

[0051]

[0052] Another embodiment of the present application is a light-emitting element containing any of the above organic compounds.

[0053] The light-emitting element in the above embodiment includes an EL layer between an anode and a cathode. The EL layer includes at least one of a light-emitting layer, a hole-transport layer, a hole-injection layer, an electron-transport layer, and an electron-injection layer. Note that the EL layer can further include another functional layer.

[0054] In the above embodiment, it is preferable that the light-emitting layer contain a light-emitting material.

[0055] Another embodiment of the present application is a display device including the light-emitting element having any of the above structures, and at least one of a color filter and a transistor. Another embodiment of the present application is an electronic device including the above display device, and at least one of a housing and a touch sensor. Another embodiment of the present application is a lighting device including the light-emitting element having any of the above structures, and at least one of a housing and a touch sensor. An embodiment of the present application includes not only a light-emitting device including a light-emitting element but also an electronic device including a light-emitting device. Thus, the light-emitting device in this specification refers to an image display device or a light source (including a lighting device). In addition, a display module in which a connector such as a flexible printed circuit (FPC) or a tape carrier package (TCP) is connected to a light-emitting device, a module in which a printed wiring board is provided in a TCP end portion, or a module in which an integrated circuit (IC) is directly mounted on a light-emitting element by a chip on glass (COG) method is also an embodiment of the present application.

[0056] According to one embodiment of the present application, a novel organic compound can be provided. In particular, a novel benzofuro[3,2-d]pyrazine compound or a novel benzothieno[3,2-d]pyrazine compound can be provided. In addition, a novel organic compound having electron-transport properties can be provided. Furthermore, a light-emitting element with a long lifetime can be provided. Furthermore, a light-emitting element with high emission efficiency can be provided. Furthermore, a light-emitting element with low driving voltage can be provided. Furthermore, a light-emitting element, a light-emitting device, and an electronic device each having high reliability can be provided. Furthermore, a light-emitting element, a light-emitting device, and an electronic device each having low power consumption can be provided.

[0057] Note that the description of these effects does not preclude the presence of other effects. One embodiment of the present application does not necessarily achieve all the effects described above. Other effects inherent to the present application will be apparent from or can be inferred from the description, drawings, claims, and the like. BRIEF DESCRIPTION OF DRAWINGS

[0058] FIG. 1A and FIG. 1B is a cross-sectional view of a light-emitting element of one embodiment of the present application, FIG. 1C is a schematic view of the energy levels in a light-emitting layer.

[0059] FIG. 2 is a cross-sectional view of a light-emitting element of one embodiment of the present application.

[0060] FIG. 3A and FIG. 3B is a schematic view of an active matrix light-emitting device of one embodiment of the present application.

[0061] FIG. 4A and FIG. 4B is a schematic view of an active matrix light-emitting device of one embodiment of the present application.

[0062] FIG. 5 is a schematic view of an active matrix light-emitting device of one embodiment of the present application.

[0063] FIG. 6A to FIG. 6D is a schematic view of an electronic device of one embodiment of the present application.

[0064] FIG. 7A to FIG. 7E is a schematic view of an electronic device of one embodiment of the present application.

[0065] FIG. 8A to FIG. 8C is a view showing an electronic device and a lighting device of one embodiment of the present application.

[0066] FIG. 9 is a view showing a lighting device of one embodiment of the present application.

[0067] FIG. 10A and FIG. 10B show NMR spectra of compounds related to Examples.

[0068] FIG. 11 show absorption and emission spectra of compounds related to Examples.

[0069] FIG. 12 show absorption and emission spectra of compounds related to Examples.

[0070] FIG. 13A and FIG. 13B show NMR spectra of compounds related to Examples.

[0071] FIG. 14 show absorption and emission spectra of compounds related to Examples.

[0072] FIG. 15 is a view showing current efficiency-luminance characteristics of a light-emitting element related to an example.

[0073] FIG. 16 FIG. 6 is a graph showing current density-voltage characteristics of the light-emitting element of the related example.

[0074] FIG. 17 FIG. 7 is a graph showing external quantum efficiency-luminance characteristics of the light-emitting element of the related example.

[0075] FIG. 18 FIG. 8 shows an emission spectrum of the light-emitting element of the related example.

[0076] FIG. 19 FIG. 9 is a graph showing the results of reliability tests of the light-emitting element of the related example.

[0077] FIG. 20 FIG. 10 is a graph showing current efficiency-luminance characteristics of the light-emitting element of the related example.

[0078] FIG. 21 FIG. 11 is a graph showing current density-voltage characteristics of the light-emitting element of the related example.

[0079] FIG. 22 FIG. 12 is a graph showing external quantum efficiency-luminance characteristics of the light-emitting element of the related example.

[0080] FIG. 23 FIG. 13 shows an emission spectrum of the light-emitting element of the related example.

[0081] FIG. 24 FIG. 14 is a graph showing the results of reliability tests of the light-emitting element of the related example. DETAILED DESCRIPTION

[0082] Embodiments of the present application will be described below with reference to the accompanying drawings. However, it is readily apparent to one of ordinary skill in the art that modes and details disclosed herein can be modified in various ways without departing from the spirit and scope of the present application. Therefore, the present application should not be interpreted as being limited to the contents described in the embodiments.

[0083] Note that in each of the drawings described in this specification, the size, the thickness, or the like of an anode, an EL layer, an intermediate layer, a cathode, or the like is sometimes exaggerated for the sake of explanation. Thus, each of the components is not limited to the size shown in the drawings, and is not limited to the relative sizes between the components.

[0084] Note that in this specification and the like, "first," "second," "third," and the like are used, as appropriate, to distinguish between a plurality of elements having substantially the same functions. Thus, for example, "first" can be replaced with "second," "third," or the like as appropriate. In addition, the ordinal numbers described in this specification and the like can not coincide with the ordinal numbers used to specify one embodiment of the present application.

[0085] In the configuration of the present application described in this specification and the like, the same symbol is used to represent the same part or a part having the same function among different drawings, and repeated description thereof is omitted. In addition, the same hatching is used to represent parts having the same function, and a reference numeral is not particularly added.

[0086] In this specification, a color is specified by three elements of hue (corresponding to the wavelength of monochromatic light), chroma (colorfulness, that is, the degree without a white spot), and lightness (brightness, that is, the intensity of light). In this specification, a color can also be specified by only one or two of the above three elements. In this specification, the case where two lights have different colors means the case where at least one of the above three elements is different, and also includes the case where the shape of the spectrum or the distribution of the relative intensity ratio of each peak of the two lights is different.

[0087] Note that in this specification, "film" and "layer" can be interchanged with each other depending on the case or state. For example, "conductive layer" can be interchanged with "conductive film" in some cases. Alternatively, "insulating film" can be interchanged with "insulating layer" in some cases.

[0088] (Embodiment 1)

[0089] In this embodiment, an organic compound and a light-emitting element of one embodiment of the present application are described.

[0090] The organic compound of one embodiment of the present application is represented by General Formula (G0).

[0091]

[0092] In General Formula (G0), X represents oxygen or sulfur, A 1 and A 2 each independently represent a substituent having 6 to 100 carbon atoms. R 1 to R 4 each independently represent hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 25 carbon atoms.

[0093] The light-emitting element including the organic compound has high emission efficiency and a low driving voltage. The organic compound has high resistance to repeated oxidation and reduction and is stable in an excited state, and thus the light-emitting element including the organic compound can have high reliability.

[0094] when the total number of carbon atoms in A 1 is 6 to 100, the reliability of the light-emitting element is greatly improved as compared to a structure in which A 1 and R 1 to R 3 are all hydrogen. This is particularly evident when the organic compound represented by General Formula (G0) is used as a host material of a light-emitting layer. This is presumably because the stability in an excited state and the stability of film properties of the organic compound are improved when a substituent is provided on one side of the benzene ring in the benzofuro[3,2-g]pyrazine skeleton or the benzothieno[3,2-g]pyrazine skeleton. It is one of the great findings of the present inventors that a substituent provided on the aromatic ring on the opposite side of the pyrazine ring and the like contributes to such improvement in reliability. On the other hand, as illustrated in General Formula (G0), by introducing a second substituent represented by A 2 with a total number of carbon atoms of 6 to 100 on the side of the pyrazine ring, the carbon and the nitrogen on the pyrazine ring are easily protected, and thus the electric stability at the time of electron transport and the stability in an excited state can be improved. In the case where A 2 has an aromatic ring or an aromatic heterocycle, the lowest unoccupied molecular orbital (also referred to as LUMO) is expanded due to interaction with the pyrazine ring, which is advantageous for electron transport properties. In other words, the organic compound preferably has two substituents of A 1 and A 2 .

[0095] The organic compound of one embodiment of the present application is an organic compound represented by General Formula (G0). In General Formula (G0), X represents oxygen or sulfur, A 1 and A 2 each independently represent a substituent with a carbon atom number of 10 to 100. R 1 to R 4 each independently represent hydrogen, an alkyl group with a carbon atom number of 1 to 6, a substituted or unsubstituted cycloalkyl group with a carbon atom number of 3 to 7, or a substituted or unsubstituted aryl group with a carbon atom number of 6 to 25.

[0096] when the total number of carbon atoms in A 1 and A 2When both of the substituents are substituents having a total of 10 to 100 carbon atoms, a molecular structure having high heat resistance can be achieved, and thus, is preferable. Importantly, in addition to heat resistance, stability in an excited state, stability of film properties, and electrical stability at the time of transporting electrons also become higher. For example, a typical example of a substituent having 6 carbon atoms is a benzene ring (phenyl group) or a substituent having a similar size. For example, by replacing this substituent with a substituent having 10 or more carbon atoms having a fused aromatic ring or a fused heteroaromatic ring, the above effects become more pronounced.

[0097] Therefore, in the above or below General Formulae (G0) to (G4), A 1 and A 2 all have a substituted or unsubstituted aromatic ring having 10 to 30 carbon atoms or a substituted or unsubstituted heteroaromatic ring having 10 to 30 carbon atoms. By adopting this structure, a structure in which a π-conjugated system extends over the entire molecule can be formed, a molecular structure having high carrier transport properties can be achieved, and thus, a light-emitting element having high reliability and low driving voltage can be provided. In addition, this structure can effectively improve electrochemical stability and film properties, and thus, the reliability of the light-emitting element can be improved. In addition, the molecular weight can be increased without reducing sublimability, and thus, a material having high heat resistance can be formed. In other words, this molecular structure in which bulky substituents having a total of 10 or more carbon atoms are provided on both the benzene ring side and the pyrazine ring side of the benzofuro[3,2-g]pyrazine skeleton or the benzo-thiopheno[3,2-g]pyrazine skeleton is one of the important structures of one embodiment of the present application.

[0098] In the above structure, as the substituted or unsubstituted aromatic ring having 10 to 30 carbon atoms or the substituted or unsubstituted heteroaromatic ring having 10 to 30 carbon atoms, a fused aromatic ring including a plurality of benzene rings, a naphthalene ring, a fluorene ring, a phenanthrene ring, a triphenylene ring, and the like can be given. In addition, a fused heteroaromatic ring including a carbazole ring, a dibenzofuran ring, or a dibenzothiophene ring (e.g., a carbazole ring, a dibenzofuran ring, a dibenzothiophene ring, a benzonaphthofuran ring, a benzonaphthothiophene ring, an indolocarbazole ring, a benzofuro[3,2-g]carbazole ring, a benzo-thiopheno[3,2-g]carbazole ring, an indenocarbazole ring, or a dibenzocarbazole ring, and the like) can be given.

[0099] Note that the substituent having 6 to 100 carbon atoms can include the above-described substituted or unsubstituted aromatic ring having 10 to 30 carbon atoms, the substituted or unsubstituted heteroaromatic ring having 10 to 30 carbon atoms, the fused aromatic ring, or the fused heteroaromatic ring, and in addition, can include a benzene ring. In other words, the fused aromatic ring, the fused heteroaromatic ring, and the benzene ring can be combined. For example, the fused heteroaromatic ring can be bonded to the benzofuro[3,2-g]pyrazine skeleton or the benzo-thiopheno[3,2-g]pyrazine skeleton through a phenylene group or a biphenyl diyl group.

[0100] More preferably, in the above or below general formulae (G0) to (G4), A 1 and A 2 each independently contains at least one of a substituted or unsubstituted benzene ring, a substituted or unsubstituted naphthalene ring, a substituted or unsubstituted phenanthrene ring, a substituted or unsubstituted triphenylene ring, a substituted or unsubstituted condensed heteroaromatic ring having 12 to 30 carbon atoms, and a substituted or unsubstituted triarylamine structure. By employing such a structure, synthesis becomes easy. These substituents have high electrochemical stability, so that an organic compound having such a structure can have high reliability. In the above structure, the condensed heteroaromatic ring is preferably a ring containing a dibenzofuran ring, a dibenzothiophene ring, or a carbazole ring (for example, a carbazole ring, a dibenzofuran ring, a dibenzothiophene ring, a benzonaphthofuran ring, a benzonaphthothiophene ring, an indolocarbazole ring, a benzofuranocarbazole ring, a benzothiophenocarbazole ring, an indenocarbazole ring, a dibenzocarbazole ring, and the like) from the viewpoint of stability of the ring and heat resistance. As the triarylamine structure, a triphenylamine structure is preferably used because the T1 level is improved. Note that if the number of aromatic hetero rings having a lone pair of electrons such as a pyridine ring in A 1 and A 2 is too large, the organic compound serves as a strong base in the excited state, and the stability is decreased. Therefore, A 1 and A 2 are preferably composed of one or more of the above rings or structures, respectively.

[0101] An organic compound of one embodiment of the present application is represented by the following general formula (G1).

[0102]

[0103] In the general formula (G1), X represents oxygen or sulfur, A 1 represents a substituent having a total of 6 to 100 carbon atoms. Ht 2 represents a substituted or unsubstituted aromatic ring having 10 to 30 carbon atoms or a substituted or unsubstituted heteroaromatic ring having 10 to 30 carbon atoms. Ar 2 represents a substituted or unsubstituted arylene group having 6 to 25 carbon atoms, R 1 to R 4 each independently represent hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 25 carbon atoms. m represents an integer of 0 to 3.

[0104] In the above structure, Ht 2A skeleton having a hole-transport property is preferable. By introducing a hole-transport property skeleton to a benzofuro[3,2-g]pyrazine skeleton or a benzothieno[3,2-g]pyrazine skeleton, a structure having both good redox properties can be formed, and thus a light-emitting element with high reliability can be provided. In addition, the carrier (electron and hole) transport property is improved, and thus a light-emitting element with low driving voltage can be provided. In particular, Ht 2 A substituted or unsubstituted condensed aromatic heterocycle including any of a carbazole ring, a dibenzofuran ring, and a dibenzothiophene ring is preferable. By employing such a structure, an organic compound having high heat resistance, stable excited state, and high T1 level can be formed.

[0105] The organic compound of one embodiment of the present application is represented by General Formula (G2).

[0106]

[0107] In General Formula (G2), X represents oxygen or sulfur, Ht 1 and Ht 2 each independently represent an aromatic ring having 10 to 30 carbon atoms or an aromatic heterocycle having 10 to 30 carbon atoms. Ar 1 and Ar 2 each independently represent a substituted or unsubstituted arylene group having 6 to 25 carbon atoms, R 1 to R 4 each independently represent hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 25 carbon atoms. n and m each independently represent an integer of 0 to 3.

[0108] In the above structure, Ar 1 or Ar 2 is preferably a substituted or unsubstituted phenylene group, and R 1 to R 4 are preferably each hydrogen. By employing such a structure, synthesis becomes easy.

[0109] In the above structure, Ht 1 and Ht 2 each independently preferably include a substituted or unsubstituted condensed aromatic heterocycle including any of a carbazole ring, a dibenzofuran ring, and a dibenzothiophene ring. By employing such a structure, an organic compound having high heat resistance, stable excited state, and high T1 level can be formed.

[0110] The organic compound of one embodiment of the present application is represented by General Formula (G3).

[0111]

[0112] In General Formula (G3), X represents oxygen or sulfur, A1 Substituents indicating a total carbon number of 10 to 100. Ht 2 It indicates a substituted or unsubstituted aromatic heterocycle containing any one of the carbazole ring, dibenzofuran ring, and dibenzothiophene ring.

[0113] An organic compound of one embodiment of the present invention is represented by the following general formula (G4).

[0114]

[0115] In the general formula (G4), X represents oxygen or sulfur. 1 and Ht 2 Each of these can be independently represented as a substituted or unsubstituted aromatic heterocycle containing any one of the following: a carbazole ring, a dibenzofuran ring, and a dibenzothiophene ring. This structure allows for the formation of organic compounds with high heat resistance, stable excited states, and high T1 energy levels.

[0116] In the above structure, Ht 1 and Ht 2 Preferably, the phenyl group is meta-bonded to the benzofuranopyrazine or benzothiophenopyrazine framework. This structure allows for the formation of structures with high T1 energy levels. Additionally, structures that are less prone to crystallization can be formed. Note that the benzofuranopyrazine or benzothiophenopyrazine framework is related to Ht. 1 and Ht 2 The bonding position between the phenyl groups is not limited to the meta position.

[0117] In the above structure, Ht 1 and Ht 2 Preferably, the substituent is represented by any one of the following general formulas (Ht-1) to (Ht-7). By employing such a substituent, a structure with high electrochemical stability and a high T1 energy level can be formed.

[0118]

[0119] An organic compound according to one embodiment of the present invention is represented by the following general formula (G5).

[0120]

[0121] In the general formula (G5), X represents oxygen or sulfur, and Z... 1 and Z 2 They can be used to represent oxygen or sulfur independently.

[0122] By employing a structure in which a dibenzofuran skeleton or a dibenzothiophene skeleton is meta-bonded to a benzofuran-pyrazine skeleton or a benzothiophene-pyrazine skeleton via a phenyl group, a structure with a high T1 energy level can be formed, and therefore it is preferred.

[0123] The organic compound of one embodiment of the present application is an organic compound represented by the following structural formula (100) or (101).

[0124]

[0125] In General Formulae (G1) and (G2), Ar 1 and Ar 2 each independently represent a substituted or unsubstituted arylene group having 6 to 25 carbon atoms, and examples of the arylene group include a phenylene group, a naphthalene group, a biphenyl group, a fluorene group, a spirofluorene group, and the like. For example, a group represented by the following structural formulae (Ar-1) to (Ar-27) can be used. Note that a group represented by Ar 1 and Ar 2 is not limited thereto and can have a substituent.

[0126]

[0127] In General Formulae (G0) to (G2) and General Formulae (Ht-1) to (Ht-7), R 1 to R 4 , R 10 to R 22 include hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 25 carbon atoms. Specifically, examples of the above alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isopropyl group, a tert-butyl group, a n-hexyl group, and the like. Examples of the above cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and the like. Examples of the above aryl group include a phenyl group, a naphthyl group, a biphenyl group, a fluorene group, a spirofluorene group, and the like. More specifically, for example, a group represented by the following structural formulae (R-1) to (R-32) can be used. Note that a group represented by R 1 to R 4 , R 10 to R 22 is not limited thereto.

[0128]

[0129] Note that in the above organic compound of one embodiment of the present application, in A 1 , A 2 , Ht 1 , Ht 2 , R 1 to R 4 , R 10 to R 22In the case of having a substituent, as the substituent, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 25 carbon atoms can be given. Specifically, as the above alkyl group, for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isopropyl group, a t-butyl group, a n-hexyl group, and the like can be given. As the above cycloalkyl group, for example, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and the like can be given. As the above aryl group, a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, a spirofluorenyl group, and the like can be given.

[0130] <Specific examples of compounds>

[0131] As specific structures of the compounds represented by General Formulae (G0) to (G5), compounds represented by the following Structural Formulae (100) to (267), and the like can be given. Note that the compounds represented by General Formulae (G0) to (G5) are not limited to the following examples.

[0132]

[0133]

[0134]

[0135]

[0136]

[0137]

[0138]

[0139]

[0140]

[0141]

[0142]

[0143]

[0144]

[0145]

[0146]

[0147]

[0148]

[0149]

[0150]

[0151]

[0152]

[0153]

[0154] The organic compound of one embodiment of the present application has a benzofuro[3,2-g]pyrazine skeleton or a benzothieno[3,2-g]pyrazine skeleton. The benzene ring in the benzofuro[3,2-g]pyrazine skeleton or the benzene ring in the benzothieno[3,2-g]pyrazine skeleton has a substituent with a total number of carbon atoms of 6 to 100. The pyrazine ring in the benzofuro[3,2-g]pyrazine skeleton or the pyrazine ring in the benzothieno[3,2-g]pyrazine skeleton has a substituent with a total number of carbon atoms of 6 to 100.

[0155] A light-emitting element including the organic compound has high emission efficiency, and the driving voltage is low. The organic compound has high resistance to oxidation and reduction, and the excited state is stable; thus, a light-emitting element including the organic compound can have high reliability.

[0156] As a host material or an electron-transport material of a light-emitting element, a compound in which a π-conjugated system typified by an aromatic compound is extended over the entire molecule is generally used. In particular, a compound having a π-electron deficient heteroaromatic skeleton is preferably used. Among the compounds having a π-electlon deficient heteroaromatic skeleton, a fused heteroaromatic skeleton having a diazine skeleton has a high T1 energy level, is stable, and has high reliability, and is thus preferable. Among them, a benzofuro[3,2-g]pyrazine skeleton and a benzothieno[3,2-g]pyrazine skeleton have high acceptor properties, and are thus particularly preferable.

[0157] In this embodiment, the present inventors introduce a first substituent with a total number of carbon atoms of 6 to 100 to one side of the benzene ring of a benzofuro[3,2-g]pyrazine skeleton or a benzothieno[3,2-g]pyrazine skeleton, and introduce a second substituent with a total number of carbon atoms of 6 to 100 to one side of the pyrazine ring of the benzofuro[3,2-g]pyrazine skeleton or the benzothieno[3,2-g]pyrazine skeleton. The organic compound is preferably used as a host material of a light-emitting element. Furthermore, a light-emitting element including the organic compound as a host material has high emission efficiency, a low driving voltage, and high reliability.

[0158] When the first substituent having a total of 6 to 100 carbon atoms is provided on one side of the benzene ring in the benzofuro[3,2-g]pyrazine skeleton or the benzothieno[3,2-g]pyrazine skeleton, the reliability of the light-emitting element is greatly improved compared to the case where the structure is not substituted. This is particularly evident in the case where the organic compound of one embodiment of the present application is used as a host material of a light-emitting layer. This can be considered to be because the stability in the excited state and the stability of film properties of the organic compound are improved when the substituent is provided on one side of the benzene ring in the benzofuro[3,2-g]pyrazine skeleton or the benzothieno[3,2-g]pyrazine skeleton. It is one of great findings of the present inventors that the substituent provided on the aromatic ring on the opposite side of the heteroaromatic ring such as a pyrazine ring brings about such an effect of improving reliability. On the other hand, by providing a second substituent having a total of 6 to 100 carbon atoms on the side of the pyrazine ring in the benzofuro[3,2-g]pyrazine skeleton or the benzothieno[3,2-g]pyrazine skeleton, the carbon and the nitrogen in the pyrazine ring are easily protected, so the electric stability at the time of electron transport and the stability in the excited state can be improved. In the case where the second substituent has an aromatic ring or a heteroaromatic ring, the LUMO is expanded due to interaction with the pyrazine ring, which is favorable for electron transport properties. In other words, the organic compound preferably has a substituent on one side of the benzene ring and on one side of the pyrazine ring in the benzofuro[3,2-g]pyrazine skeleton or the benzothieno[3,2-g]pyrazine skeleton.

[0159] The organic compound having a benzofuro[3,2-g]pyrazine skeleton or a benzothieno[3,2-g]pyrazine skeleton of one embodiment of the present application can be synthesized by a cyclization reaction of a unit having a pyrazine ring and a unit having a benzene ring. By utilizing this reaction, the object can be obtained simply and at low cost, and thus this is preferable.

[0160] Note that in the case where the organic compound of one embodiment of the present application has a substituent at the 2-position on the side of the pyrazine ring in the benzofuro[3,2-g]pyrazine skeleton or the benzothieno[3,2-g]pyrazine skeleton, the T1 level is increased, whereas in the case where the organic compound has a substituent at the 3-position, the T1 level is decreased. This property is favorable for a host material when a light-emitting substance that can convert triplet excitation energy into light emission is used. For example, the T1 level when the organic compound has a substituent at the 2-position is suitable when the light-emitting substance that exhibits blue to green light emission is used, and the T1 level when the organic compound has a substituent at the 3-position is suitable when the light-emitting substance that exhibits red light emission is used. Such a degree of freedom in design is an effect that is difficult to obtain when a benzofuro[3,2-g]pyrimidine is used.

[0161] The organic compound having a benzofuro[3,2-g]pyrazine skeleton or a benzothieno[3,2-g]pyrazine skeleton of one embodiment of the present application has a low LUMO level, and has high electron transport properties. Thus, by using the organic compound, a light-emitting element with low driving voltage can be provided. Furthermore, the organic compound has a low LUMO level, and has good redox properties, so a light-emitting element with high reliability can be provided.

[0162] When both the first substituent and the second substituent are substituents having a total number of carbon atoms of 10 to 100, the organic compound of one embodiment of the present application has a molecular structure with high heat resistance, and is therefore preferred. Furthermore, when the organic compound has the above substituents, the stability in the excited state, the stability of film properties, and the electric stability at the time of transporting electrons can be improved. For example, typical examples of a substituent having 6 carbon atoms are a benzene ring (phenyl group) or a substituent having a similar size. For example, by replacing the substituent with a substituent having 10 or more carbon atoms and having a condensed aromatic ring or a condensed heteroaromatic ring, the above effects become more pronounced.

[0163] From the above viewpoint, it is particularly preferred that both the first substituent and the second substituent have a substituted or unsubstituted aromatic ring having 10 to 30 carbon atoms or a substituted or unsubstituted heteroaromatic ring having 10 to 30 carbon atoms. With such a structure, a structure in which a π-conjugated system extends over the entire molecule can be formed, a molecular structure with high carrier-transporting properties can be achieved, and thus a light-emitting element with high reliability and low driving voltage can be provided. Thus, such a molecular structure in which bulky substituents having a total number of carbon atoms of 10 or more are provided on both the benzene ring side and the pyrazine ring side of the benzo-furanopyrazine skeleton or the benzo-thiophenopyrazine skeleton is one of important structures of one embodiment of the present application.

[0164] In the above structure, as the substituted or unsubstituted aromatic ring having 10 to 30 carbon atoms or the substituted or unsubstituted heteroaromatic ring having 10 to 30 carbon atoms, a condensed aromatic ring such as a naphthalene ring, a fluorene ring, a phenanthrene ring, or a triphenylene ring can be given. In addition, a condensed heteroaromatic ring including a carbazole ring, a dibenzofuran ring, or a dibenzothiophene ring (e.g., a carbazole ring, a dibenzofuran ring, a dibenzothiophene ring, a benzonaphthofuran ring, a benzonaphthothiophene ring, an indolocarbazole ring, a benzofuranocarbazole ring, a benzothiophenocarbazole ring, an indenocarbazole ring, or a dibenzocarbazole ring) can be given.

[0165] Note that as the first substituent and the second substituent, for example, an aromatic hydrocarbon group, an aromatic heterocyclic group, or a substituent having an aromatic amine skeleton can be given. More specifically, a substituent including a substituted or unsubstituted benzene ring, a substituted or unsubstituted naphthalene ring, a substituted or unsubstituted phenanthrene ring, a substituted or unsubstituted triphenylene ring, a substituted or unsubstituted condensed aromatic heterocyclic ring having 12 to 30 carbon atoms, and a triarylamine structure can be given. These substituents have high electrochemical stability, and thus a light-emitting element including these substances can have high reliability. From the viewpoint of stability of the ring and heat resistance, the condensed aromatic heterocyclic ring is preferably a ring including a dibenzofuran ring, a dibenzothiophene ring, or a carbazole ring (e.g., a carbazole ring, a dibenzofuran ring, a dibenzothiophene ring, a benzonaphthofuran ring, a benzonaphthothiophene ring, an indolocarbazole ring, a benzofurocarbazole ring, a benzothiophenecarbazole ring, an indenocarbazole ring, a dibenzocarbazole ring, and the like). As the triarylamine structure, a triphenylamine structure is preferably used because the T1 level is increased.

[0166] Note that if the aromatic heterocyclic group having a six-membered ring with a lone pair of electrons such as a pyridine ring is too much in the first substituent and the second substituent, the organic compound functions as a strong base in an excited state, and the stability is decreased. Thus, the first substituent and the second substituent are preferably each formed of one or more of the above-described rings or structures.

[0167] Here, the second substituent preferably has a hole-transport skeleton. By introducing a hole-transport skeleton into a benzofuro[3,2-g]pyrazine skeleton or a benzothiopheno[3,2-g]pyrazine skeleton, a structure in which both redox characteristics are favorable can be formed, and thus a light-emitting element with high reliability can be provided. In addition, the carrier (electron and hole) transportability is increased, and thus a light-emitting element with low driving voltage can be provided.

[0168] The hole-transport skeleton preferably has a triarylamine structure or a π-electron rich aromatic heterocyclic ring. An organic compound having a triarylamine structure or a π-electron rich aromatic heterocyclic ring has high hole-transportability, and thus a light-emitting element including the organic compound can be driven at low voltage. As the π-electron rich aromatic heterocyclic ring, for example, a ring including any of a pyrrole ring, a furan ring, and a thiophene ring can be given. When the π-electron rich aromatic heterocyclic ring includes any of a dibenzofuran ring, a dibenzothiophene ring, and a carbazole ring, the heat resistance of the organic compound is increased, the structure of the ring is stable, and the T1 level is high, and thus is preferable. As the triarylamine structure, a triphenylamine structure is preferably used because it has high hole-transportability. Note that the hole-transport skeleton is not limited thereto.

[0169] The substituent on one side of the pyrazine ring of the benzofuro[3,2-g]pyrazine skeleton or the benzothieno[3,2-g]pyrazine skeleton can also have one or more arylene groups and a hole-transporting skeleton, but the end of the substituent is preferably a hole-transporting skeleton. The structure of the substituent on one side of the pyrazine ring of the benzofuro[3,2-g]pyrazine skeleton or the benzothieno[3,2-g]pyrazine skeleton is preferably a structure in which the pyrazine ring is directly bonded to a hole-transporting skeleton or a structure in which a hole-transporting skeleton is bonded to the benzofuro[3,2-g]pyrazine skeleton or the benzothieno[3,2-g]pyrazine skeleton through one or more arylene groups. By employing such a structure, an organic compound having a high T1 level can be obtained.

[0170] It is preferable that the substituent be at the 2-position on one side of the pyrazine ring of the benzofuro[3,2-g]pyrazine skeleton or the benzothieno[3,2-g]pyrazine skeleton. By employing such a structure, an organic compound having a high T1 level can be obtained. Note that the position of the substituent is not limited to the 2-position.

[0171] The organic compound of one embodiment of the present application includes both a benzofuro[3,2-g]pyrazine skeleton or a benzothieno[3,2-g]pyrazine skeleton having electron-transporting properties and a substituent having hole-transporting properties in one molecule, and thus can be regarded as a bipolar material. Such a material has a good carrier-transporting property, and thus by using the material as a host material of a light-emitting element, a light-emitting element with a low driving voltage can be provided, and is preferable.

[0172] The organic compound of one embodiment of the present application has a π-electron-rich heteroaromatic ring (e.g., a dibenzofuran skeleton, a dibenzothiophene skeleton, a carbazole skeleton) and a π-electron-deficient heteroaromatic ring (a benzofuro[3,2-g]pyrazine skeleton or a benzothieno[3,2-g]pyrazine skeleton). Thus, an excited state of a donor-acceptor type is easily formed in the molecule. Furthermore, by bonding the π-electron-rich heteroaromatic ring and the π-electlon-deficient heteroaromatic ring directly or through an arylene group, the donor property and the acceptor property can be enhanced. By enhancing the donor property and the acceptor property in the molecule, a portion in which the region of the molecular orbital distribution of the highest occupied molecular orbital (HOMO) and the region of the molecular orbital distribution of the LUMO overlap in the compound can be reduced, and the excitation energy difference between the singlet excitation level and the triplet excitation level of the compound can be reduced. Furthermore, the triplet excitation level of the compound can be kept high. Note that the "molecular orbital" refers to the spatial distribution of an electron in a molecule and can show the probability of finding an electron. The electronic configuration of a molecule (spatial distribution and energy of an electron) can be described in detail by a molecular orbital.

[0173] When the energy difference between the singlet excitation energy level and the triplet excitation energy level is small, the triplet excitation energy can be converted into singlet excitation energy by reverse intersystem crossing using a small amount of thermal energy at 100°C or lower, preferably room temperature. That is, the compound of one embodiment of the present application is suitable for use as a compound having a function of converting triplet excitation energy into singlet excitation energy. Furthermore, it is suitable for use as a compound having a function of converting triplet excitation energy into singlet excitation energy and then converting it into light emission. In order to efficiently cause reverse intersystem crossing, the energy difference between the singlet excitation energy level and the triplet excitation energy level is preferably greater than 0 eV and less than or equal to 0.3 eV, more preferably greater than 0 eV and less than or equal to 0.2 eV, and further preferably greater than 0 eV and less than or equal to 0.1 eV.

[0174] Note that when the region where the molecular orbital distribution of the HOMO and the region where the molecular orbital distribution of the LUMO overlap and the transition dipole moment between the HOMO level and the LUMO level is greater than 0, light emission can be obtained from an excited state (e.g., a lowest singlet excited state) related to the HOMO level and the LUMO level. Thus, the compound of one embodiment of the present application is suitable for use as a light-emitting material having a function of converting triplet excitation energy into singlet excitation energy, i.e., as a thermally activated delayed fluorescence material.

[0175] As described above, the organic compound of one embodiment of the present application is suitable for use as a host material in the case where a light-emitting substance capable of converting triplet excitation energy into light emission is used. Thus, the following light-emitting element is also one embodiment of the present application: a light-emitting element including an EL layer between a pair of electrodes, wherein the EL layer includes a substance having the above-described benzofuro[3,2-g]pyrazine skeleton or benzothieno[3,2-g]pyrazine skeleton, and the EL layer includes a light-emitting layer including a substance having the above-described benzofuro[3,2-g]pyrazine skeleton or benzothieno[3,2-g]pyrazine skeleton and a substance capable of converting triplet excitation energy into light emission. At this time, the substance capable of converting triplet excitation energy into light emission is preferably a phosphorescent compound described later.

[0176] Note that the organic compound of the present embodiment 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.

[0177] Note that the present embodiment can be combined with other embodiments as appropriate.

[0178] (Embodiment 2)

[0179] In this embodiment, a method for synthesizing the organic compound of one embodiment of the present application, i.e., a benzofuro[3,2-g]pyrazine compound or a benzothieno[3,2-g]pyrazine compound represented by General Formula (G0) will be described. As the method for synthesizing the compound, various reactions can be used. For example, the compound represented by General Formula (G0) can be synthesized by the following simple synthesis scheme.

[0180]

[0181] First, the benzofuro[3,2-g]pyrazine compound or benzothieno[3,2-g]pyrazine compound represented by (M-1) as a starting material of the general formula (G0) can be synthesized by the following synthesis scheme (A-1). The intermediate (Am-3) is obtained by coupling an aryl boronic acid substituted with a methoxy group or a methylthio group (m-1) with a pyrazine compound substituted with an amino group and a halogen (m-2). By subjecting the intermediate to a cyclization reaction with tert-butyl nitrite, the benzofuro[3,2-g]pyrazine compound or benzothieno[3,2-g]pyrazine compound (M-1) can be obtained.

[0182] (A-1)

[0183] In the synthesis scheme (A-1), X represents oxygen or sulfur, Y 1 and Y 2 each independently represent a halogen. R 1 to R 4 each independently represent hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, a substituted or unsubstituted aryl group having 6 to 25 carbon atoms, and B1 represents a boronic acid, a boronic acid ester, or a cyclic triol borate salt or the like. As the cyclic triol borate salt, a lithium salt, a potassium salt, or a sodium salt can be used.

[0184] Next, as shown in the synthesis scheme (A-2), (M-1) obtained by the above synthesis reaction (A-1) is coupled with boronic acid compounds (M-2) and (M-3), whereby the organic compound of one embodiment of the present application, that is, the benzofuro[3,2-g]pyrazine compound or benzothieno[3,2-g]pyrazine compound represented by the general formula (G0) can be obtained. Alternatively, the benzofuro[3,2-g]pyrazine compound or benzothieno[3,2-g]pyrazine compound represented by the general formula (G0) can be obtained by coupling (M-1) with the boronic acid compound (M-3) to obtain an intermediate and coupling the intermediate with the boronic acid compound (M-2).

[0185] (A-2)

[0186]

[0187] In the synthesis scheme (A-2), X represents oxygen or sulfur, A 1 and A 2 each independently represent a substituent having 6 to 100 carbon atoms. R 1 to R 4 each independently represent hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, a substituted or unsubstituted aryl group having 6 to 25 carbon atoms, Y 1 and Y 2B2and B3each independently represent a boronic acid, a boronic acid ester, or a cyclic triol borate, etc. As the cyclic triol borate, a lithium salt, a potassium salt, or a sodium salt can be used.

[0188] As the compounds (m-1), (m-2), (M-2), and (M-3), various kinds of compounds are sold on the market, or these compounds can be synthesized, so a large variety of the benzofuro[3,2-g]pyrazine compounds or benzothieno[3,2-g]pyrazine compounds represented by General Formula (G0) can be synthesized. Therefore, the compound of one embodiment of the present application has a feature of a large variety of kinds.

[0189] The above describes one example of a synthesis method of the benzofuro[3,2-g]pyrazine compound or the benzothieno[3,2-g]pyrazine compound of the compound of one embodiment of the present application, but the present application is not limited to this and can be synthesized by any other synthesis method.

[0190] Note that the compound of this embodiment can be used in appropriate combination with the structures of other embodiments.

[0191] (Embodiment 3)

[0192] In this embodiment, reference is made to FIG. 1A to FIG. 1C A light-emitting element of one embodiment of the present application is described below.

[0193] <Structure Example 1 of Light-Emitting Element>

[0194] First, a structure of a light-emitting element of one embodiment of the present application is described below. FIG. 1A to FIG. 1C A structure of a light-emitting element of one embodiment of the present application is described below.

[0195] FIG. 1A is a schematic cross-sectional view of a light-emitting element 150 of one embodiment of the present application.

[0196] The light-emitting element 150 includes a pair of electrodes (an electrode 101 and an electrode 102) and an EL layer 100 between the pair of electrodes. The EL layer 100 includes at least a light-emitting layer 140.

[0197] FIG. 1A The EL layer 100 illustrated in FIG. 1 includes, in addition to the light-emitting layer 140, a functional layer such as a hole-injection layer 111, a hole-transport layer 112, an electron-transport layer 118, and an electron-injection layer 119.

[0198] Although this embodiment describes electrode 101 and electrode 102 as the anode and cathode, respectively, the structure of the light-emitting element 150 is not limited to this. That is, electrode 101 can be used as the cathode and electrode 102 as the anode, and the layers between the electrodes can be stacked in reverse order. In other words, the hole injection layer 111, hole transport layer 112, light-emitting layer 140, electron transport layer 118, and electron injection layer 119 can be stacked sequentially from the anode side.

[0199] The structure of EL layer 100 is not limited to FIG. 1A The structure shown may include at least one selected from hole injection layer 111, hole transport layer 112, electron transport layer 118, and electron injection layer 119. Alternatively, the EL layer 100 may also include functional layers that can: reduce the injection barrier of holes or electrons; improve the transport of holes or electrons; hinder the transport of holes or electrons; or suppress quenching caused by electrodes, etc. Note that the functional layers may be single layers or stacked layers.

[0200] In the light-emitting element 150, at least one layer of the EL layer 100 contains an organic compound according to one embodiment of the present invention. Note that the layer containing the organic compound is preferably an electron transport layer 118, and more preferably a light-emitting layer 140. Furthermore, as described above, it is preferable to use an organic compound according to one embodiment of the present invention as the host material 141 in the light-emitting layer 140, and to use a luminescent material (especially a phosphorescent compound) capable of converting a triple excitation energy into light emission as the guest material 142.

[0201] FIG. 1B It is shown FIG. 1A A cross-sectional schematic diagram of an example of the light-emitting layer 140 shown. FIG. 1B The luminescent layer 140 shown includes a host material 141 and a guest material 142. The host material 141 may be composed of an organic compound, or it may be a co-host material comprising organic compound 141_1 and organic compound 141_2. In one embodiment of the present invention, the organic compound may be used as the host material 141 or organic compound 141_1.

[0202] As the guest material 142, a luminescent organic material can be used. Examples of such luminescent organic materials include materials that emit fluorescence (hereinafter also referred to as fluorescent materials) and materials that emit phosphorescence (hereinafter also referred to as phosphorescent materials). The structure of using a phosphorescent material as the guest material 142 will be described below. Note that the guest material 142 can also be referred to as a phosphorescent material.

[0203] exist FIG. 1BIn the case of co-hosts, the organic compound 141_1 and the organic compound 141_2 are contained in the light-emitting layer, as illustrated. In general, an electron-transport material and a hole-transport material are used as the two host materials. By using such a structure, the hole-injection barrier between the hole-transport layer 112 and the light-emitting layer 140 and the electron-injection barrier between the electron-transport layer 118 and the light-emitting layer 140 can be reduced, which can reduce the driving voltage, and thus is preferable.

[0204] <Light-emitting mechanism of the light-emitting element>

[0205] Next, a light-emitting mechanism of the light-emitting layer 140 will be described.

[0206] The organic compound 141_1 and the organic compound 141_2 included in the host material 141 in the light-emitting layer 140 form an exciplex.

[0207] FIG. 1C The energy level correlation of the organic compound 141_1, the organic compound 141_2, and the guest material 142 in the light-emitting layer 140 is illustrated. The description and the symbols in the following formula are as follows: FIG. 1C

[0208] Host (141_1): Organic compound 141_1 (host material);

[0209] Host (141_2): Organic compound 141_2 (host material);

[0210] Guest (142): Guest material 142 (phosphorescent compound);

[0211] S PH1 : S1 level of the organic compound 141_1 (host material);

[0212] T PH1 : T1 level of the organic compound 141_1 (host material);

[0213] S PH2 : S1 level of the organic compound 141_2 (host material);

[0214] T PH2 : T1 level of the organic compound 141_2 (host material);

[0215] S PG : S1 level of the guest material 142 (phosphorescent compound);

[0216] T PG : T1 level of the guest material 142 (phosphorescent compound); ​

[0217] S PE The S1 energy level of the excitocomplex; and

[0218] T PE : T1 energy level of excitocomplex.

[0219] Organic compound 141_1 and organic compound 141_2 form an excitocomplex, and the S1 energy level (S1) of this excitocomplex... PE ) and T1 energy level (T PE ) become adjacent energy levels (refer to) FIG. 1C Path E1).

[0220] Exciton complexes are rapidly formed by one of organic compounds 141_1 and 141_2 accepting a hole and the other accepting an electron. Alternatively, when one becomes excited, it rapidly forms an exciton complex by interacting with the other. Thus, most of the excitons in the luminescent layer 140 exist as exciton complexes. The excitation energy level (S) of the exciton complexes... PE or T PE The S1 energy level (S1) of the host materials (organic compound 141_1 and organic compound 141_2) forming the excitocomplex is higher than that of the excitocomplex. PH1 and S PH2 The excitation energy is low, so the excited state of the host material 141 can be formed with a lower excitation energy. As a result, the driving voltage of the light-emitting element can be reduced.

[0221] By excitocomplex S PE and T PE The energy of both materials is transferred to the T1 energy level of the guest material 142 (phosphorescent compound), resulting in luminescence (see reference). FIG. 1C Paths E2 and E3).

[0222] Furthermore, the T1 energy level (T) of the excitocomplex PE The preferred T1 energy level (T) of the guest material 142 is preferred. PG The singlet and triplet excitation energies of the resulting excitocomplex can be derived from the S1 level (S1) of the excitocomplex. PE ) and T1 energy level (T PE The energy level (T1) is transferred to the T1 level of the guest material 142. PG ).

[0223] Note that in order to efficiently transfer the excitation energy from the excimer complex to the guest material 142, the T1 energy level (T1) of the excimer complex is required. PE Preferably, the T1 energy level (T1) of the organic compounds (organic compound 141_1 and organic compound 141_2) forming the excitocomplex is equal to or lower than that of the organic compounds forming the excitocomplex. PH1 and TPH2 ). Thus, quenching of the triplet excitation energy of the exciplex caused by each of the organic compounds (the organic compound 141_1 and the organic compound 141_2) is not easily generated, and energy transfer from the exciplex to the guest material 142 efficiently occurs.

[0224] When the combination of the organic compound 141_1 and the organic compound 141_2 is a combination of a compound having a hole-transport property and a compound having an electron-transport property, the carrier balance can be easily controlled by adjusting the mixing ratio thereof. Specifically, the weight ratio of the compound having a hole-transport property : the compound having an electron-transport property is preferably in the range of 1 : 9 to 9 : 1. By employing this structure, the carrier balance can be easily controlled, and thus the carrier recombination region can also be easily controlled.

[0225] In this specification and the like, the process of the above-described paths E2 and E3 is sometimes referred to as exciplex-triplet energy transfer (ExTET). In other words, in the light-emitting layer 140, supply of excitation energy from an exciplex to the guest material 142 is generated. In this case, it is not necessarily required to make the efficiency of reverse intersystem crossing from T PE to S PE The efficiency of reverse intersystem crossing from T PE The luminescence quantum yield of S

[0226] The combination of the organic compound 141_1 and the organic compound 141_2 can be any combination that can form an exciplex, and preferably, the HOMO level and the LUMO level of one of them are lower than the HOMO level and the LUMO level (Lowest Unoccupied Molecular Orbital) of the other, respectively.

[0227] <Materials>

[0228] Next, the components of the light-emitting element according to one embodiment of the present application are described in detail below.

[0229] <Light-emitting layer>

[0230] In the light-emitting layer 140, the host material 141 is the highest in weight ratio, and the guest material 142 is dispersed in the host material 141. In the case where the guest material 142 is a fluorescent compound, the S1 energy level of the host material 141 (the organic compound 141_1 and the organic compound 141_2) of the light-emitting layer 140 is preferably higher than the S1 energy level of the guest material (the guest material 142) of the light-emitting layer 140. In the case where the guest material 142 is a phosphorescent compound, the T1 energy level of the host material 141 (the organic compound 141_1 and the organic compound 141_2) of the light-emitting layer 140 is preferably higher than the T1 energy level of the guest material (the guest material 142) of the light-emitting layer 140.

[0231] The organic compound 141_1 is preferably a compound having a nitrogen-containing six-membered heteroaromatic skeleton. In particular, the organic compound of one embodiment of the present application has a pyrazine skeleton, and thus is suitable for the organic compound 141_1. As other specific examples, a compound having a pyridine skeleton, a diazine skeleton (a pyrazine skeleton, a pyrimidine skeleton, and a pyridazine skeleton), and a triazine skeleton can be given. As the above-described compound having a nitrogen-containing aromatic heteroaromatic skeleton having basicity, for example, a pyridine compound, a bipyridine compound, a pyrimidine compound, a triazine compound, a quinoxaline compound, a bisbenzoquinoxaline compound, a phenanthroline compound, a purine compound, and the like can be given. As the organic compound 141_1, a material having higher electron-transport property than hole-transport property (an electron-transport material) can be used, and a material having an electron mobility of 1 x 10 -6 cm 2 or more can be preferably used.

[0232] Specifically, for example, heterocyclic compounds having a pyridine skeleton such as bathophenanthroline (abbreviation: BPhen), bathocuproin (abbreviation: BCP), and the like; heterocyclic compounds having a dipyrazine skeleton such as 2-[3-(dibenzo[f,h]thiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzo[f,h]thiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4-(3,6-diphenyl-9H-carbazol-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzPDBq-III), 7-[3-(dibenzo[f,h]thiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 7mDBTPDBq-II), and 6-[3-(dibenzo[f,h]thiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II), 2-[3-(3,9'-bi-9H-carbazol-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzCzPDBq), 4,6-bis[3-(phenanthren-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(4-dibenzo[f,h]thiophenyl)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 triazine skeleton such as 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), and the like; heterocyclic compounds having a pyridine skeleton such as 3,5-bis[3-(9H-carbazol-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy), 1,3,5-tris[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB), and the like can be used. Among the above heterocyclic compounds, heterocyclic compounds having a triazine skeleton, a dipyrazine (pyrimidine, pyrazine, pyridazine) skeleton, or a pyridine skeleton are stable and have good reliability, and thus are preferable. Furthermore, heterocyclic compounds having such a skeleton have high electron-transport properties, and are also useful in reduction in driving voltage. Furthermore, high molecular compounds such as poly(2,5-pyridinediyl) (abbreviation: PPy), poly[(9,9-dihexylfluorene-2,7-diyl)-co-(pyridine-3,5-diyl)] (abbreviation: PF-Py), and poly[(9,9-dioctylfluorene-2,7-diyl)-co-(2,2'-bipyridine-6,6'-diyl)] (abbreviation: PF-BPy) can be used. The substances described here mainly have a light-emitting property of 1 x 10 -6 cm 2A substance having an electron mobility of 1 x 10"5cmVsor more. Note that other substances can be used as long as they are substances whose electron transport property is higher than their hole transport property.

[0233] As the organic compound 141_2, a compound having a nitrogen-containing five-membered heterocyclic skeleton or a tertiary amine skeleton is preferably used. Specifically, a compound having a pyrrole skeleton or an aromatic amine skeleton can be given. For example, an indole compound, a carbazole compound, a triarylamine compound, or the like can be given. As the nitrogen-containing five-membered heterocyclic skeleton, an imidazole skeleton, a triazole skeleton, and a tetrazole skeleton can be given. As the organic compound 141_2, a material (hole transport material) whose hole transport property is higher than its electron transport property can be used, and a material having a hole mobility of 1 x 10"5cmVsor more is preferably used. -6 cm 2 A material having a hole mobility of 1 x 10"5cmVsor more. Furthermore, the above hole transport material can also be a high molecular compound.

[0234] As examples of the aromatic amine compound which can be used as a material whose hole transport property is high, 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-(l,r-biphenyl)-4,4'-diamine (abbreviation: DNTPD), 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), and the like can be given.

[0235] As the carbazole compound, specifically, 3-[N-(4-diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzDPA1), 3,6-bis[N-(4-diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzDPA2), 3,6-bis[N-(4-diphenylaminophenyl)-N-(l-naphthyl)amino]-9-phenylcarbazole (abbreviation: PCzTPN2), 3-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2), 3-[N-(l-naphthyl)-N-(9-phenylcarbazol-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1), and the like can be given.

[0236] As the carbazole compounds, 4,4'-bis(N-carbazolyl)diphenyl (abbreviation: CBP), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzene (abbreviation: TCPB), 9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: CzPA), 1,4-bis[4-(N-carbazolyl)phenyl]-2,3,5,6-tetraphenylbenzene, and the like can be given.

[0237] In addition, N,N-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole-3-amine (abbreviation: CzAlPA), 4-(10-phenyl-9-anthryl)triphenylamine (abbreviation: DPhPA), 4-(9H-carbazol-9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole-3-amine (abbreviation: PCAPA), N,9-diphenyl-N-{4-[4-(10-phenyl-9-anthryl)phenyl]phenyl}-9H-carbazole-3-amine (abbreviation: PCAPBA), N,9-diphenyl-N-(9,10-diphenyl-2-anthryl)-9H-carbazole-3-amine (abbreviation: 2PCAPA), 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: PCzPA), 3,6-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: DPCzPA), N,N,N',N',N",N",N",N"'-octaphenyldibenzo[g,p] (chrysene)-2,7,10,15-tetramine (abbreviation: DBC1), and the like can be given.

[0238] In addition, poly(N-vinylcarbazole) (abbreviation: PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA), poly[N-(4-{N'-[4-(4-diphenylamino)phenyl]phenyl-N'-phenylamino}phenyl)methylacrylamide] (abbreviation: PTPDMA), poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine] (abbreviation: Poly-TPD), and the like high molecular compounds can be given.

[0239] As a material having a high hole-transport property, 4,4'-bis[N-(l-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB or α-NPD), N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[l,l'-biphenyl]-4,4'-diamine (abbreviation: TPD), 4,4',4"-tris(carbazol-9-yl)triphenylamine (abbreviation: TCTA), 4,4',4"-tris[N-(l-naphthyl)-N-phenylamino]triphenylamine (abbreviation: l'-TNATA), 4,4',4"-tris(N,N-diphenylamino)triphenylamine (abbreviation: TDATA), 4,4',4"-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (abbreviation: MTDATA), 4,4'-bis[N-(spiro-9,9'-bifluorene-2-yl)-N-phenylamino]biphenyl (abbreviation: BSPB), 4-phenyl-4'-(9-phenylfluorene-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluorene-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 (abbreviation: DPNF), 2-[N-(4-diphenylaminophenyl)-N-phenylamino]spiro-9,9'-bifluorene (abbreviation: DPASF), 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4"-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(l-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-di(l-naphthyl)-4"-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB), 4-phenyldiphenyl-(9-phenyl-9H-carbazol-3-yl)amine (abbreviation: PCAlBP), N,N'-bis(9-phenylcarbazol-3-yl)-N,N'-diphenylbenzene-l,3-diamine (abbreviation: PCA2B), N,N',N"-triphenyl-N,N',N"-tris(9-phenylcarbazol-3-yl)benzene-l,3,5-triamine (abbreviation: PCA3B), N-(4-biphenyl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-9-phenyl-9H-carbazol-3-amine (abbreviation: PCBiF), N-(l,l'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: PCBBiF), 9,9-Dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]fluorene-2-amine (abbreviated as: PCBAF), N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]spiro-9,9'-bifluorene-2-amine (abbreviated as: PCBASF), 2-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]spiro-9,9'-bifluorene (abbreviated as: PCASF), 2, Aromatic amine compounds such as 7-bis[N-(4-diphenylaminophenyl)-N-phenylamino]spiro-9,9'-bifluorene (abbreviated as DPA2SF), N-[4-(9H-carbazole-9-yl)phenyl]-N-(4-phenyl)phenylaniline (abbreviated as YGA1BP), and N,N'-bis[4-(carbazole-9-yl)phenyl]-N,N'-diphenyl-9,9-dimethylfluorene-2,7-diamine (abbreviated as YGA2F). Alternatively, amine compounds and carbazole compounds such as 3-[4-(1-naphthyl)-phenyl]-9-phenyl-9H-carbazole (abbreviated as PCPN), 3-[4-(9-phenanthyl)-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 CzTP), 3,6-bis(9H-carbazol-9-yl)-9-phenyl-9H-carbazole (abbreviated as PhCzGI), and 2,8-bis(9H-carbazol-9-yl)-dibenzothiophene (abbreviated as Cz2DBT) can also be used. Among the above compounds, compounds with pyrrole skeletons and aromatic amine skeletons are stable and reliable, and are therefore preferred. Furthermore, compounds with the aforementioned framework exhibit high hole transport properties, which also contributes to the reduction of the driving voltage.

[0240] As an organic compound 141_2, compounds with nitrogen-containing five-membered heterocyclic skeletons such as imidazole, triazole, or tetraazole skeletons can be used. Specifically, for example, 3-(4-biphenyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviated as 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-phenyltriyl)tris(1-phenyl-1H-benzimidazole) (abbreviated as TPBI), 2-[3-(dibenzothiophene-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviated as mDBTBIm-II), etc.

[0241] In the luminescent layer 140, there are no particular restrictions on the guest material 142; anthracene compounds, tetraphenyl compounds, etc., are preferred as fluorescent compounds. (chrysene) compounds, phenanthrene compounds, pyrene compounds, perylene compounds, stilbene compounds, acridinone compounds, coumarin compounds, phenoxazine compounds, phenothiazine compounds, and the like, for example, can be used.

[0242] Specifically, as the material, 5,6-bis[4-(10-phenyl-9-anthryl)phenyl]-2,2'-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl-9-anthryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2BPy), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn), N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn), N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-N,N'-bis(4-tert-butylphenyl)pyrene-1,6-diamine (abbreviation: 1,6tBu-FLPAPrn), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-3,8-dicyclohexylpyrene-1,6-diamine (abbreviation: ch-1,6FLPAPrn), N,N'-bis[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazol-9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), 4-(9H-carbazol-9-yl)-4'-(9,10-diphenyl-2-anthryl)triphenylamine (abbreviation: 2YGAPPA), N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: PCAPA), perylene, 2,5,8,11-tetra(tert-butyl)perylene (abbreviation: TBP), 4-(10-phenyl-9-anthryl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAPA), N,N"-(2-tert-butylanthracen-9,10-diylbis-4,1-phenylene)bis[N,N',N'-triphenyl-1,4-phenylenediamine] (abbreviation: DPABPA), N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: 2PCAPPA), N-[4-(9,10-diphenyl-2-anthryl)phenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPPA), N,N,N',N',N",N",N",N"'-octaphenylchrysene-2,7-diamine (abbreviation: C-8PAP), N,N,N',N',N"-2,6-di-tert-pentyl-4,8-dimethyl-9H-carbazol-3,6-diamine (abbreviation: 2mMem-DCM), N,N,N',N'-2,6-di-tert-pentyl-9H-carbazol-3,6-diamine (abbreviation: 2mMem-DCM), N,N,N',N'-tetraphenylbenzidine (abbreviation: TPD), N,N'-diphenyl-N,N'-bis(1-naphthyl)-1,1'-biphenyl-4,4'-diamine (abbreviation: NPB), and the like can be used. (chrysene)-2,7,10,15-tetraamine (abbreviation: DBC1), Coumarin 30, N-(9,10-diphenyl-2-anthryl)-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCAPA), N-[9,10-bis(1,1 '-biphenyl-2-yl)-2-anthryl]-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCABPhA), N-(9,10-diphenyl-2-anthryl)-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPA), N-[9,10-bis(1,1 '-biphenyl-2-yl)-2-anthryl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPABPhA), 9,10-bis(1,1 '-biphenyl-2-yl)-N-[4-(9H-carbazol-9-yl)phenyl]-N-phenylanthracen-2-amine (abbreviation: 2YGABPhA), N,N,9-triphenylanthracen-9-amine (abbreviation: DPhAPhA), Coumarin 6, Coumarin 545T, N,N'-diphenylquinacridone (abbreviation: DPQd), Rubrene, 2,8-di-tert-butyl-5,11-bis(4-tert-butylphenyl)-6,12-diphenyl-tetraphthalane (abbreviation: TBRb), Nile Red, 5,12-bis(1,1 '-biphenyl-4-yl)-6,11-diphenyl-tetraphthalane (abbreviation: BPT), 2-(2-{2-[4-(dimethylamino)phenyl]ethenyl}-6-methyl-4H-pyran-4- ylidene)malonitrile (abbreviation: DCM1), 2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1 H,5H-benzo[ij]quinolizol-9-yl)ethenyl]-4H-pyran-4- ylidene}malonitrile (abbreviation: DCM2), N,N,N',N'-tetrakis(4-methylphenyl) naphthacene-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-N,N,N',N'-tetrakis(4-methylphenyl) acenaphtho[1,2-a]fluoranthene-3,10-diamine (abbreviation: p-mPhAFD), 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1 H,5H-benzo[ij]quinolizol-9-yl)ethenyl]-4H-pyran-4- ylidene}malonitrile (abbreviation: DCJTI), 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1 H,5H-benzo[ij]quinolizol-9-yl)ethenyl]-4H-pyran-4- ylidene}malonitrile (abbreviation: DCJTB), 2-(2,6-bis{2-[4-(dimethylamino)phenyl]ethenyl}-4H-pyran-4-ylidene)malonitrile (abbreviation: BisDCM), 2-{2,6-bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1 H,5H-benzo[ij]quinolizol-9-yl)ethenyl]-4H-pyran-4- ylidene}malonitrile (abbreviation: BisDCM1), 2,3,6,7-tetramethyl-2,3,6,7-tetrahydro-1 H,5H-benzo[ij]quinolizol-9-yl (abbreviation: Me-DCM), 2,3,6,7-tetrahydro-1 H,5H-benzo[ij]quinolizol-9-yl (abbreviation: DCML), 2,3,6,7-tetrahydro-1 H,5H-benzo[ij]quinolizol-9-yl (abbreviation: DCM), 2,3,6,7-tetrahydro-1 H,5H-benzo[ij]quinolizol-9-yl (abbreviation: DCJ), 2,3,6,7-tetrahydro-1 H,5H-benzo[ij]quinolizol-9-yl (abbreviation: DCJTB), 2,3,6,7-tetrahydro-1 H,5H-benzo[ij]quinolizol-9-yl (abbreviation: DCJTI), 2,3,6,7-tetrahydro-1 H,5H-benzo[ij]quinolizol-9-yl (abbreviation: DCML), 2,3,6,7-tetrahydro-1 H,5H-benzo[ij]quinolizol-9-yl (abbreviation: DCM), 2,3,6,7-tetrahydro-1 H,5H-benzo[ij]quinolizol-9-yl (abbreviation: DCJ), 2,3,6,7-tetrahydro-1 H,5H-benzo[ij]quinolizol-9-yl (abbreviation: DCJTB), 2,3,6,7-tetrahydro-1 H,5H-benzo[ij]quinolizol-9-yl (abbreviation: DCJTI), 2,3,6,7-tetrahydro-1 H,5H-benzo[ij]quinolizol-9-yl (abbreviation: DCML), 2,3,6,7-tetrahydro-1 H,5H-benzo[ij]quinolizol-9-yl (abbreviation: DCM), 2,3,6,7-tetrahydro-1 H,5H-benzo[ij]quinolizol-9-yl (abbreviation: DCJ), 2,3,6,7-tetrahydro-1 H,5H-benzo[ij]quinolizol-9-yl (abbreviation: DCJTB), 2,3,6,7-tetrahydro-1 H,5H-benzo[ij]quinolizol-9-yl (abbreviation: DCJTI), 2,3,6,7-tetrahydro-1 H,5H-benzo[ij]quinolizol-9-yl (abbreviation: DCML), 2,3,6,7-tetrahydro-1 H,5H-benzo[ij]quinolizol-9-yl (abbreviation: DCM), 2,3,6,7-tetrahydro-1 H,5H-benzo[ij]quinolizol-9-yl (abbreviation: DCJ), 2,3,6,7-tetrahydro-1 H,5H-benzo[ij]quinolizol-9-yl (abbreviation: DCJTB), 2,3,6,7-tetrahydro-1 H,5H-benzo[ij]quinolizol-9-yl (abbreviation: DCJTI), 2,3,6,7-tetrahydro-1 H,5H-benzo[ij]quinolizol-9-yl (abbreviation: DCML), 2,3,6,7-tetrahydro-1 H,5H-benzo[ij]quinolizol-9-yl (abbreviation: DCM), 2,3,6,7-tetrahydro-1 H,5H-benzo[ij]quinolizol-9-yl (abbreviation: DCJ), 2,3,6,7-tetrahydro-1 H,5H-benzo[ij]quinolizol-9-yl (abbreviation: DCJTB), 2,3,6,7-tetrahydro-1 H,5H-benzo[ij]quinolizol-9-yl (abbreviation: DCJTI), 2,3,6,7-tetrahydro-1 H,5H-benzo[ij]quinolizol-9-yl (abbreviation: DCML), 2,3,6,7-tetrahydro-1 H,5H-benzo[ij]quinolizol-9-yl (abbreviation: DCM), 2,3,6,7-tetrahydro-1 H,5H-benzo[i5H-benzo[ij]quinolizine-9-yl)vinyl]-4H-pyranyl-4-ylidene}propanedinitrile (abbreviation: BisDCJTM), 5,10,15,20-tetraphenylbisbenzo[tetraphenylbisbenzo][5,6]indeno[1,2,3-cd:1',2',3'-lm]pentalene, and the like.

[0243] As the guest material 142 (phosphorescent compound), iridium, rhodium, platinum-based organometallic complexes, or metal complexes can be given, and among them, an organic iridium complex such as an iridium-based ortho-metalated complex is preferable. As the ligand ortho-metalated, a 4H-triazole ligand, a 1H-triazole ligand, an imidazole ligand, a pyridine ligand, a pyrimidine ligand, a pyrazine ligand, or an isoquinoline ligand, or the like can be given. As the metal complex, a platinum complex having a porphyrin ligand, or the like can be given.

[0244] As the substance having a light emission peak in the wavelength region of blue or green, for example, an organic metal iridium complex having a 4H-triazole skeleton such as 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) (abbreviation: Ir(Mptz)3), tris[4-(3-biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazole]iridium(III) (abbreviation: Ir(iPrptz-3b)3), tris[3-(5-biphenyl)-5-isopropyl-4-phenyl-4H-1,2,4-triazole]iridium(III) (abbreviation: Ir(iPr5btz)3), and the like; an organic metal iridium complex having a 1H-triazole skeleton such as tris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazole]iridium(III) (abbreviation: Ir(Mptz1-mp)3), tris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazole)iridium(III) (abbreviation: Ir(Prptz1-Me)3), and the like; an organic metal iridium complex having an imidazole skeleton such as fac-tris[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]iridium(III) (abbreviation: Ir(iPrpmi)3), tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(III) (abbreviation: Ir(dmpimpt-Me)3), and the like; and a metal complex such as bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2 ']iridium(III) tetrakis(1-pyrazolyl)borate (abbreviation: FIr6), bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2Ir(III) picolinate (abbreviation: FIrpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinato-N,C 2 Ir(III) picolinate (abbreviation: FIrpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinato-N,C 2 Ir(III) picolinate (abbreviation: FIrpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinato-N,C

[0245] Ir(III) picolinate (abbreviation: FIrpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinato-N,C 2 Ir(III) picolinate (abbreviation: FIrpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinato-N,C 2acetylacetonate (abbreviation: Ir(pq)2(acac)), and the like; and organic metal iridium complexes having a pyridine skeleton such as bis(2-phenylpyridinato-N,C 2′ ) iridium (III) (abbreviation: Ir(pq)3), bis(2-phenylpyridinato-N,C 2 ) iridium (III) acetylacetonate (abbreviation: Ir(pq)2(acac)), and the like; and organic metal iridium complexes having a pyridine skeleton such as bis(2,4-diphenyl-1,3-oxazolato-N,C 2 ) iridium (III) acetylacetonate (abbreviation: Ir(pq)2(acac)), and the like; and organic metal iridium complexes having a pyridine skeleton such as bis(2,4-diphenyl-1,3-oxazolato-N,C 2 ) iridium (III) acetylacetonate (abbreviation: Ir(pq)2(acac)), and the like; and organic metal iridium complexes having a pyridine skeleton such as bis(2,4-diphenyl-1,3-oxazolato-N,C 2 ) iridium (III) acetylacetonate (abbreviation: Ir(pq)2(acac)), and the like; and organic metal iridium complexes having a pyridine skeleton such as bis(2,4-diphenyl-1,3-oxazolato-N,C

[0246] As a substance having a light emission peak in a wavelength region of yellow or red, for example, there can be given organic metal iridium complexes having a pyrimidine skeleton such as (diisobutyromethanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium (III) (abbreviation: Ir(5mdppm)2(dibm)), bis[4,6-bis(3-methylphenyl)pyrimidinato](dipivaloylmethanato)iridium (III) (abbreviation: Ir(5mdppm)2(dpm)), bis[4,6-di(naphthalen-1-yl)pyrimidinato](dipivaloylmethanato)iridium (III) (abbreviation: Ir(d1npm)2(dpm)), and the like; organic metal iridium complexes having a pyrazine skeleton such as (acetylacetonato)bis(2,3,5-triphenylpyrazinato)iridium (III) (abbreviation: Ir(tppr)2(acac)), bis(2,3,5-triphenylpyrazinato)(dipivaloylmethanato)iridium (III) (abbreviation: Ir(tppr)2(dpm)), (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalino]iridium (III) (abbreviation: Ir(Fdpq)2(acac)), and the like; tris(1-phenylisoquinolinato-N,C 2’ ) iridium (III) (abbreviation: Ir(piq)3), bis(1-phenylisoquinolinato-N,C2’ ) iridium (III) acetylacetone (abbreviation: Ir (piq) 2 (acac) ) and the like having a pyridine skeleton; platinum complexes such as 2, 3, 7, 8, 12, 13, 17, 18-octylethyl-21H, 23H-porphine platinum (II) (abbreviation: PtOEP) ; and rare earth metal complexes such as tris (1, 3-diphenyl-1, 3-propanedionato) (bathophen) europium (III) (abbreviation: Eu (DBM) 3 (Phen) ), tris [1- (2-thienoyl) -3, 3, 3-trifluoropropanedionato] (bathophen) europium (III) (abbreviation: Eu (TTA) 3 (Phen) ), and the like. Among the above substances, since the organic metal iridium complex having a pyrimidine skeleton also has remarkably excellent reliability and luminous efficiency, it is particularly preferable. In addition, the organic metal iridium complex having a pyrazine skeleton can achieve red light with good chromaticity.

[0247] Since the organic compound having a benzofuro [3, 2- c] pyrazine skeleton or a benzothieno [3, 2- c] pyrazine skeleton has a high T1 energy level, it is suitable for use as a host material of a light-emitting layer using a substance capable of converting a triplet excitation energy into light emission as a light-emitting material. Therefore, as the light-emitting material included in the light-emitting layer 140, a material capable of converting a triplet excitation energy into light emission is preferably used. As the material capable of converting a triplet excitation energy into light emission, in addition to the phosphorescent compound described above, a thermally activated delayed fluorescence (TADF) material can be given. Therefore, the description about the phosphorescent compound can be regarded as the description about the thermally activated delayed fluorescence material. Note that the thermally activated delayed fluorescence material refers to a material in which the difference between the triplet excitation energy level and the singlet excitation energy level is small and which has a function of converting energy from the triplet excitation state to the singlet excitation state by reverse intersystem crossing. Thus, the triplet excitation state can be up-converted to the singlet excitation state (i.e., reverse intersystem crossing can occur) by a small amount of thermal energy and light emission (fluorescence) from the singlet excitation state can be efficiently exhibited. In addition, the condition under which TADF can be efficiently obtained is that the energy difference between the triplet excitation energy level and the singlet excitation energy level is greater than 0 eV and is 0.2 eV or less, preferably greater than 0 eV and is 0.1 eV or less. As the thermally activated delayed fluorescence material, the compound described in Embodiment 1 can also be used.

[0248] When the thermally activated delayed fluorescence material is composed of one material, for example, the following material can be used.

[0249] First, examples of the above-mentioned compound include a fullerene or a compound thereof, an acridine compound such as a proflavine, and eosin. In addition, examples of the metal-containing porphyrin include a metal-containing porphyrin containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), or palladium (Pd). Examples of the metal-containing porphyrin include a proto-porphyrin-tin fluoride complex (abbreviation: SnF2(Proto IX)), a meso-porphyrin-tin fluoride complex (abbreviation: SnF2(Meso IX)), a hemato-porphyrin-tin fluoride complex (abbreviation: SnF2(Hemato IX)), a copro-porphyrin tetramethyl ester-tin fluoride complex (abbreviation: SnF2(Copro III-4Me)), an octaethyl porphyrin-tin fluoride complex (abbreviation: SnF2(OEP)), an etio-porphyrin-tin fluoride complex (abbreviation: SnF2(Etio I)), and an octaethyl porphyrin-platinum chloride complex (abbreviation: PtCl2OEP).

[0250] As a thermally activated delayed fluorescence material composed of one material, a heterocyclic compound having a π-electron rich aromatic heterocycle and a π-electon deficient aromatic heterocycle can also be used. Specifically, 2-(diphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazol-l l-yl)-l,3,5-triazine (abbreviation: PIC-TRZ), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-l,3,5-triazine (abbreviation: PCCzPTzn), 2-[4-(10H-phenoxazine-10-yl)phenyl]-4,6-diphenyl-l,3,5-triazine (abbreviation: PXZ-TRZ), 3-[4-(5-phenyl-5,10-dihydrophenoxazin-10-yl)phenyl]-4,5-diphenyl-l,2,4-triazole (abbreviation: PPZ-3TPT), 3-(9,9-dimethyl-9H-acridin-10-yl)-9H-xanthen-9-one (abbreviation: ACRXTN), bis[4-(9,9-dimethyl-9,10-dihydroacridin)phenyl]sulfone (abbreviation: DMAC-DPS), 10-phenyl-10H,10'H-spiro[acridine-9,9'-xanthene]-10'-one (abbreviation: ACRSA), and the like can be given. This heterocyclic compound has a π-electron rich aromatic heterocycle and a π-electron deficient aromatic heterocycle, and thus has high electron-transport property and hole-transport property, and is preferable. Among skeletons having a π-electron deficient aromatic heterocycle, a diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton) or a triazine skeleton is stable and has high reliability, and is particularly preferable. Among skeletons having a π-electron rich aromatic heterocycle, an acridine skeleton, a phenoxazine skeleton, a thiophene skeleton, a furan skeleton, and a pyrrole skeleton are stable and have high reliability, and it is preferable to have one or more selected from these skeletons. As the pyrrole skeleton, an indole skeleton, a carbazole skeleton, and a 3-(9-phenyl-9H-carbazol-3-yl)-9H-carbazole skeleton are particularly preferable. Note that, in a substance in which a π-electron rich aromatic heterocycle and a π-electron deficient aromatic heterocycle are directly bonded to each other, both the donor property of the π-electron rich aromatic heterocycle and the acceptor property of the π-electron deficient aromatic heterocycle are strong, and the difference between the energy level of the singlet excited state and the energy level of the triplet excited state is small, and thus is particularly preferable.

[0251] The light-emitting layer 140 can also include a material other than the host material 141 and the guest material 142.

[0252] There is no particular limitation on the material that can be used for the light-emitting layer 140, and for example, a fused polycyclic aromatic compound such as an anthracene compound, a phenanthrene compound, a pyrene compound, a chrysene compound, a tetracene compound, a coronene compound, a dibenzo[g,p]chrysene compound, and the like can be given. Specifically, 9,10-diphenylanthracene (abbreviation: DPAnth), 6,12-dimethoxy-5,11-diphenyl 9, 10-bis (3, 5-diphenylphenyl) anthracene (abbreviation: DPPA), 9, 10-di (2-naphthyl) anthracene (abbreviation: DNA), 2-tert-butyl-9, 10-di (2-naphthyl) anthracene (abbreviation: t-BuDNA), 9, 9'-bianthracene (abbreviation: BANT), 9, 9'- (stilbene-3, 3'-diyl) diphenanthrene (abbreviation: DPNS), 9, 9'- (stilbene-4, 4'-diyl) diphenanthrene (abbreviation: DPNS2), 1, 3, 5-tri (1-pyrenyl) benzene (abbreviation: TPB3), and the like. In addition, one or more kinds of substances having a singlet excitation level or a triplet excitation level higher than the excitation level of the above-described guest material 142 can be selected from the above-described substances and publicly known substances.

[0253] For example, a compound having an aromatic heterocyclic skeleton such as an oxadiazole compound can be used for the light-emitting layer 140. Specifically, for example, heterocyclic compounds such as 2- (4-biphenyl) -5- (4-tert-butylphenyl) -1, 3, 4-oxadiazole (abbreviation: PBD), 1, 3-bis [5- (p-tert-butylphenyl) -1, 3, 4-oxadiazol-2-yl] benzene (abbreviation: OXD-7), 9- [4- (5-phenyl-1, 3, 4-oxadiazol-2-yl) phenyl] -9H-carbazole (abbreviation: COll), 4, 4'-bis (5-methylbenzoxazol-2-yl) stilbene (abbreviation: BzOs), and the like can be given.

[0254] In addition, a metal complex having a heterocycle (e.g., a zinc and aluminum-based metal complex) or the like can be used for the light-emitting layer 140. For example, a metal complex including a quinoline ligand, a benzoquinoline ligand, an oxazole ligand, or a thiazole ligand can be given. Specifically, a metal complex having a quinoline skeleton or a benzoquinoline skeleton or the like, such as tris (8-hydroxyquinoline) aluminum (III) (abbreviation: Alq), tris (4-methyl-8-hydroxyquinoline) aluminum (III) (abbreviation: Almq3), bis (10-hydroxybenzo [h] quinoline) beryllium (II) (abbreviation: BeBq2), bis (2-methyl-8-hydroxyquinoline) (4-phenylphenol) aluminum (III) (abbreviation: BAlq), bis (8-hydroxyquinoline) zinc (II) (abbreviation: Znq), and the like can be given. In addition, a metal complex having an oxazolyl-based or thiazole-based ligand or the like, such as bis [2- (2-benzoxazolyl) phenol] zinc (II) (abbreviation: ZnPBO), bis [2- (2-benzothiazolyl) phenol] zinc (II) (abbreviation: ZnBTZ), and the like can be used.

[0255] The light-emitting layer 140 can also be formed of a plurality of layers of two or more layers. For example, in the case where a first light-emitting layer and a second light-emitting layer are stacked in this order from the hole-transporting layer side to form the light-emitting layer 140, a substance having hole-transporting properties can be used as a host material of the first light-emitting layer, and a substance having electron-transporting properties can be used as a host material of the second light-emitting layer. In addition, the light-emitting materials included in the first light-emitting layer and the second light-emitting layer can be the same or different materials. In addition, the materials can have a function of emitting light of the same color or a function of emitting light of different colors. By using light-emitting materials having a function of emitting light of different colors from each other as the two layers of the light-emitting layer, respectively, a plurality of light emissions can be obtained at the same time. In particular, the light-emitting materials used for each light-emitting layer are preferably selected so that white light emission can be obtained by combining the light emitted by the two layers of the light-emitting layer.

[0256] Note that the light-emitting layer 140 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. In addition to the above materials, the light-emitting layer 140 can include an inorganic compound such as a quantum dot or a high molecular compound (an oligomer, a dendrimer, a polymer, or the like).

[0257] Hole injection layer

[0258] The hole injection layer 111 has a function of reducing an injection barrier of holes from one of a pair of electrodes (the electrode 101 or the electrode 102) to promote hole injection, and is formed using, for example, a transition metal oxide, a phthalocyanine compound, or an aromatic amine. As the transition metal oxide, a molybdenum oxide, a vanadium oxide, a ruthenium oxide, a tungsten oxide, a manganese oxide, or the like can be given. As the phthalocyanine compound, phthalocyanine, a metal phthalocyanine, or the like can be given. As the aromatic amine, a benzidine compound, a phenylenediamine compound, or the like can be given. In addition, a high molecular compound such as a polythiophene or a polyaniline can also be used, and typical examples are poly(ethylenedioxythiophene) / poly(styrenesulfonic acid) which is self-doped with a polythiophene.

[0259] As the hole injection layer 111, a layer having a composite material composed of a hole transporting material and a material having a property of accepting an electron from the hole transporting material can be used. Alternatively, a stack of a layer containing an electron accepting material and a layer containing a hole transporting material can also be used. Charge transfer can be performed between these materials in a steady state or in a state where an electric field is present. As the electron accepting material, an organic acceptor such as a quinodimethane compound, a tetrachlorobenzoquinone compound, a hexaazatriphenylene compound, or the like can be given. Specifically, a compound having an electron-withdrawing group (halogen group or cyano group) such as 7,7,8,8-tetracyano-2,3,5,6-tetrachloroquinodimethane (abbreviation: F4-TCNQ), chloranil, 2,3,6,7,10,1 l-hexacyano-l,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT-CN), or the like can be given. Further, a transition metal oxide such as an oxide of a metal belonging to Group 4 to Group 8 can be used. Specifically, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, rhenium oxide, or the like can be used. Use of molybdenum oxide is particularly preferable because it is stable in the air, has low hygroscopicity, and is easy to handle.

[0260] As the hole transporting material, a material having a higher hole transporting property than an electron transporting property can be used, and a material having a hole mobility of 1 x 10 -6 cm 2 or more, preferably 1 x 10

[0261] As the aromatic hydrocarbon, for example, 2-tert-butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA), 2-tert-butyl-9,10-di(l-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-l-naphthyl)anthracene (abbreviation: DMNA), 2-tert-butyl-9,10-bis[2-(l-naphthyl)phenyl]anthracene, 9,10-bis[2-(l-naphthyl)phenyl]anthracene, 2,3,6,7-tetramethyl-9,10-di(l-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, and the like can be given. In addition to the above, pentacene, coronene, and the like can also be used. More preferably, an aromatic hydrocarbon having a hole mobility of 1 x 10 -6 cm 2 Vs or higher and having a carbon number of 14 to 42 is used.

[0262] The aromatic hydrocarbon can also have a vinyl skeleton. As the aromatic hydrocarbon having a vinyl group, for example, 4,4'-bis(2,2-diphenylvinyl)biphenyl (abbreviation: DPVBi), 9,10-bis[4-(2,2-diphenylvinyl)phenyl]anthracene (abbreviation: DPVPA), and the like can be given.

[0263] In addition, a thiophene compound, a furan compound, a fluorene compound, a triphenylene compound, a phenanthrene compound, or the like, such as 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II), 4,4',4"-(benzene-1,3,5-triyl)tris(dibenzofuran) (abbreviation: DBF3P-II), 1,3,5-tris(dibenzothiophene-4-yl)benzene (abbreviation: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV), 4-[3-(triphenylene-2-yl)phenyl]dibenzothiophene (abbreviation: mDBTPTp-II), or the like, can be used. Among them, a compound having at least one of a pyrrole skeleton, a furan skeleton, a thiophene skeleton, and an aromatic amine skeleton is stable and has high reliability, and is thus preferable. In addition, a compound having the above skeleton has high hole-transport property, and is also effective in reducing the driving voltage.

[0264] Hole transport layer

[0265] The hole transport layer 112 is a layer containing a hole transport material, and a material exemplified for the hole injection layer 111 can be used. In order to give the hole transport layer 112 a function of transporting holes injected into the hole injection layer 111 to the light-emitting layer 140, the highest occupied molecular orbital (HOMO) level of the hole transport layer 112 is preferably the same as or close to the HOMO level of the hole injection layer 111.

[0266] As the hole transport material, a substance having a hole mobility of 1 x 10 -6 cm 2 -2 cmVsor more is preferably used. Note that a substance other than the above substance can be used as long as the substance has higher hole-transport property than electron-transport property. The layer including a substance having high hole-transport property is not limited to a single layer, and two or more layers including the above substance can be stacked.

[0267] Electron transport layer

[0268] The electron transport layer 118 has a function of transporting electrons injected from the other of the pair of electrodes (the electrode 101 or the electrode 102) through the electron injection layer 119 to the light-emitting layer 140. As an electron-transport material, a material having higher electron-transport property than hole-transport property can be used, and a substance having a hole mobility of 1 x 10 -6 cm 2having an electron-transporting property. Since the organic compound of one embodiment of the present application has a pyrazine skeleton, it is suitable for a compound that easily accepts an electron. As other specific examples, a pyridine compound, a bipyridine compound, a pyrimidine compound, a triazine compound, a quinoxaline compound, a dipyrenyl quinoxaline compound, a phenanthroline compound, a triazole compound, a benzimidazole compound, an oxadiazole compound, and the like, which are listed as the electron-transporting material that can be used in the light-emitting layer 140, can be given. Note that it is preferable that the electron-transporting material have an electron mobility of 1 x 10 -6 cm 2 having an electron mobility of 1 x 10

[0269] In addition, a metal complex having a hetero ring can also be given, and for example, a metal complex including a quinoline ligand, a benzoquinoline ligand, an oxazole ligand, or a thiazole ligand can be given. Specifically, a metal complex having a quinoline skeleton or a benzoquinoline skeleton, such as tris(8-hydroxyquinoline)aluminum (III) (abbreviation: Alq), tris(4-methyl-8-quinolinolato)aluminum (III) (abbreviation: Almq3), bis(10-hydroxybenzo[h]quinolinato)beryllium (II) (abbreviation: BeBq2), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum (III) (abbreviation: BAlq), bis(8-hydroxyquinolinate)zinc (II) (abbreviation: Znq), and the like can be given. In addition, a metal complex having an oxazole-based ligand or a thiazole-based ligand, such as bis[2-(2-benzoxazolyl)phenolato]zinc (II) (abbreviation: ZnPBO), bis[2-(2-benzothiazolyl)phenolato]zinc (II) (abbreviation: ZnBTZ), and the like can be used.

[0270] In addition, a layer that controls movement of an electron carrier can be provided between the electron-transport layer 118 and the light-emitting layer 140. The layer that controls movement of an electron carrier is a layer in which a small amount of a substance having a high electron-trapping property is added to the above-described material having a high electron-transporting property, and by suppressing movement of an electron carrier, carrier balance can be adjusted. Such a structure is effective in suppressing a problem (e.g., a decrease in element lifetime) that occurs in a case where the electron-transporting property of an electron-transporting material is much higher than the hole-transporting property of a hole-transporting material.

[0271]

[0272] ​The electron injection layer 119 has a function of promoting electron injection by lowering the electron injection barrier at the interface between the electron injection layer 119 and the electrode 102, and for example, a Group 1 metal, a Group 2 metal, or an oxide, halide, carbonate, or the like thereof can be used. In addition, a composite of the above-described electron-transporting material and a material that exhibits electron-donating property with respect to the electron-transporting material can also be used. As the material that exhibits electron-donating property, a Group 1 metal, a Group 2 metal, or an oxide or the like thereof can be given. Specifically, lithium fluoride (LiF), sodium fluoride (NaF), cesium fluoride (CsF), calcium fluoride (CaF2), and an alkali metal such as lithium oxide (LiO x ), an alkaline earth metal, or a compound of these metals can be used. In addition, a rare earth metal compound such as erbium fluoride (ErF3) can be used. In addition, an electron salt can be used for the electron injection layer 119. As the electron salt, for example, a substance that donates electrons to calcium oxide-aluminum oxide at a high concentration or the like can be given. In addition, a substance that can be used for the electron-transporting layer 118 can be used for the electron injection layer 119.

[0273] In addition, a composite of an organic compound and an electron donor (donor) can be used for the electron injection layer 119. Such a composite has excellent electron-injection property and electron-transporting property because of generation of electrons in the organic compound by the electron donor. In this case, the organic compound is preferably a material that has excellent performance in transporting the generated electrons. Specifically, for example, a substance (metal complex, heteroaromatic compound, or the like) that forms the electron-transporting layer 118 described above can be used. As the electron donor, a substance that exhibits electron-donating property with respect to the organic compound can be given. Specifically, an alkali metal, an alkaline earth metal, and a rare earth metal can be given, and lithium, sodium, cesium, magnesium, calcium, erbium, ytterbium, or the like can be given. In addition, an alkali metal oxide or an alkaline earth metal oxide can be given, and lithium oxide, calcium oxide, barium oxide, or the like can be given. Furthermore, a Lewis base such as magnesium oxide can be used. In addition, an organic compound such as tetrathiafulvalene (abbreviation: TTF) can be used.

[0274] Note that each of the above-described light-emitting layer, hole injection layer, hole-transporting layer, electron-transporting layer, and electron injection layer can be formed by an evaporation method (including a vacuum evaporation method), an inkjet method, a coating method, a gravure printing method, or the like. In addition to the above-described materials, an inorganic compound such as a quantum dot or a high molecular compound (oligomer, dendrimer, polymer, or the like) can be used for the above-described light-emitting layer, hole injection layer, hole-transporting layer, electron-transporting layer, and electron injection layer.

[0275] Quantum Dot

[0276] A quantum dot is a semiconductor nanocrystal whose size is several nm to several tens of nm, and includes 1 x 10 3 to 1 x 10 6atoms. The energy movement of the quantum dots depends on their size, and thus, even quantum dots including the same substance have mutually different light emission wavelengths depending on the size. Therefore, by changing the size of the quantum dots used, the light emission wavelength can be easily changed.

[0277] The peak width of the emission spectrum of the quantum dots is narrow, and thus, light emission with high color purity can be obtained. Further, the theoretical internal quantum efficiency of the quantum dots is considered to be almost 100%, that is, greatly exceeds 25% of organic compounds exhibiting fluorescent light emission, and is equal to organic compounds exhibiting phosphorescent light emission. Therefore, by using the quantum dots as a light emitting material, a light emitting element with high light emission efficiency can be obtained. Also, the quantum dots, which are inorganic materials, are also excellent in practical stability, and thus, a light emitting element with a long lifetime can be obtained.

[0278] As a material constituting the quantum dots, the fourteenth group element, the fifteenth group element, the sixteenth group element, a compound including a plurality of the fourteenth group element, a compound of the fourth group to the fourteenth group element and the sixteenth group element, a compound of the second group element and the sixteenth group element, a compound of the thirteenth group element and the fifteenth group element, a compound of the thirteenth group element and the seventeenth group element, a compound of the fourteenth group element and the fifteenth group element, a compound of the eleventh group element and the seventeenth group element, iron oxide-based, titanium oxide-based, sulfur-based spinel-based, various semiconductor clusters, and the like can be given.

[0279] Specifically, mention can be made of cadmium selenide, cadmium sulfide, cadmium telluride, zinc selenide, zinc oxide, zinc sulfide, zinc telluride, mercury sulfide, mercury selenide, mercury telluride, indium arsenide, indium phosphide, gallium arsenide, gallium phosphide, indium nitride, gallium nitride, indium antimonide, gallium antimonide, aluminum phosphide, aluminum arsenide, aluminum antimonide, lead selenide, lead telluride, lead sulfide, indium selenide, indium telluride, indium sulfide, gallium selenide, arsenic sulfide, arsenic selenide, arsenic telluride, antimony sulfide, antimony selenide, antimony telluride, bismuth sulfide, bismuth selenide, bismuth telluride, silicon, silicon carbide, germanium, tin, selenium, tellurium, boron, carbon, boron nitride, boron phosphide, boron arsenide, aluminum nitride, aluminum sulfide, barium sulfide, barium selenide, barium telluride, calcium sulfide, calcium selenide, calcium telluride, beryllium sulfide, beryllium selenide, beryllium telluride, magnesium sulfide, magnesium selenide, germanium sulfide, germanium selenide, germanium telluride, tin sulfide, tin selenide, tin telluride, lead oxide, copper fluoride, copper chloride, copper bromide, copper iodide, copper oxide, copper selenide, nickel oxide, cobalt oxide, cobalt sulfide, iron oxide, iron sulfide, manganese oxide, molybdenum sulfide, vanadium oxide, tungsten oxide, tantalum oxide, titanium oxide, zirconium oxide, silicon nitride, germanium nitride, aluminum oxide, barium titanate, cadmium zinc selenide compounds, indium arsenic phosphorus compounds, cadmium selenium sulfide compounds, cadmium selenium telluride compounds, indium gallium arsenide compounds, indium gallium selenide compounds, indium selenium sulfide compounds, copper indium sulfide compounds, and combinations thereof, but are not limited thereto. A so-called alloy-type quantum dot in which the composition is expressed by any number can also be used. For example, because an alloy-type quantum dot of cadmium selenium sulfide can change the wavelength of light emission by changing the content ratio of the elements, the alloy-type quantum dot of cadmium selenium sulfide is one of means effective to obtain blue light emission.

[0280] As the quantum dot, any one of a core-type quantum dot, a core-shell type quantum dot, a core-multi-shell type quantum dot, and the like can be used. Note that by forming a shell by using another inorganic material that covers the core and has a wider band gap, the influence of defects or dangling bonds present on the surface of the nanocrystal can be reduced. Since the quantum efficiency of light emission can be greatly improved, it is preferable to use a core-shell type or a core-multi-shell type quantum dot. As an example of the material of the shell, mention can be made of zinc sulfide or zinc oxide.

[0281] Since the proportion of surface atoms of the quantum dots is high, the reactivity is high and aggregation easily occurs. Therefore, the surface of the quantum dots is preferably attached with a protective agent or provided with a protective group. By the attachment of the protective agent or the provision of the protective group, aggregation can be prevented and the solubility to solvents can be improved. The reactivity can also be reduced and the electric stability can be improved. As the protective agent (or protective group), for example, polyoxyethylene alkyl ether such as lauryl alcohol polyoxyethylene ether, polyoxyethylene stearate, polyoxyethylene lauryl ether, and the like; trialkyl phosphine such as tripropyl phosphine, tributyl phosphine, trihexyl phosphine, trioctyl phosphine, and the like; polyoxyethylene alkyl phenyl ether such as polyoxyethylene n-octyl phenyl ether, polyoxyethylene n-nonyl phenyl ether, and the like; tertiary amine such as tri(n-hexyl)amine, tri(n-octyl)amine, tri(n-decyl)amine, and the like; organophosphorus compound such as tripropyl phosphine oxide, tributyl phosphine oxide, trihexyl phosphine oxide, trioctyl phosphine oxide, tridecyl phosphine oxide, and the like; polyethylene glycol diester such as polyethylene glycol dilaurate, polyethylene glycol distearate, and the like; organic nitrogen compound such as pyridine, lutidine, collidine, quinoline, and the like; aminoalkane such as hexylamine, octylamine, decylamine, dodecylamine, tetradecylamine, hexadecylamine, octadecylamine, and the like; dialkyl sulfide such as dibutyl sulfide, and the like; dialkyl sulfoxide such as dimethyl sulfoxide, dibutyl sulfoxide, and the like; organic sulfur compound such as thiophene, and the like; higher fatty acid such as palmitic acid, stearic acid, oleic acid, and the like; alcohol; sorbitan fatty acid ester; fatty acid-modified polyester; tertiary amine-modified polyurethane; polyethyleneimine, and the like can be exemplified.

[0282] The smaller the size of the quantum dot, the larger the band gap, and therefore the size is appropriately adjusted to obtain light of a desired wavelength. The smaller the crystal size, the more the light emission of the quantum dot shifts toward the blue side (i.e., the high-energy side), and therefore, by changing the size of the quantum dot, the light emission wavelength can be adjusted to the wavelength region of the spectrum of light in the ultraviolet region, the visible light region, and the infrared region. The size (diameter) of the quantum dot generally used is 0.5 nm to 20 nm, and preferably 1 nm to 10 nm. The smaller the size distribution of the quantum dot, the narrower the emission spectrum, and therefore light emission with high color purity can be obtained. The shape of the quantum dot is not particularly limited, and can be spherical, rod-shaped, disc-shaped, or the like. Quantum rods, which are rod-shaped quantum dots, have a function of exhibiting light with directivity, and therefore by using a quantum rod as a light emitting material, a light emitting element with higher external quantum efficiency can be obtained.

[0283] In the organic EL element, the concentration quenching of the light-emitting material is generally suppressed by dispersing the light-emitting material in a host material, and the light-emitting efficiency is improved. The host material needs to have a singlet excitation energy level or a triplet excitation energy level higher than that of the light-emitting material. In particular, when a blue phosphorescent material is used as the light-emitting material, a host material having a triplet excitation energy level higher than that of the blue phosphorescent material and a long service life is required, and development of such a material is extremely difficult. Here, the quantum dots can ensure the light-emitting efficiency even when a light-emitting layer is formed using only the quantum dots without using a host material, and thus a light-emitting element with a long service life can be obtained. When the light-emitting layer is formed using only the quantum dots, the quantum dots preferably have a core-shell structure (including a core-multi-shell structure).

[0284] In the case where the quantum dots are used as the light-emitting material of the light-emitting layer, the thickness of the light-emitting layer is 3 nm to 100 nm, and preferably 10 nm to 100 nm. The ratio of the quantum dots contained in the light-emitting layer is 1 vol. % to 100 vol.%. Note that the light-emitting layer is preferably formed of only the quantum dots. In order to form a light-emitting layer in which the quantum dots are dispersed in a host material as the light-emitting material, the quantum dots can be dispersed in the host material or the host material and the quantum dots can be dissolved or dispersed in a suitable liquid medium, and a wet method (spin coating method, casting method, dye coating method, blade coating method, roll coating method, inkjet method, printing method, spray coating method, curtain coating method, Langmuir-Blodgett method, or the like) can be used. The light-emitting layer using a phosphorescent light-emitting material preferably uses a vacuum evaporation method in addition to the wet method described above.

[0285] As the liquid medium for the wet method, for example, ketones such as methyl ethyl ketone and cyclohexanone; fatty acid esters such as ethyl acetate; halogenated hydrocarbons such as dichlorobenzene; aromatic hydrocarbons such as toluene, xylene, mesitylene, and cyclohexylbenzene; aliphatic hydrocarbons such as cyclohexane, decaline, and dodecane; and organic solvents such as dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) can be used.

[0286] One Pair of Electrodes

[0287] 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.

[0288] 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, aluminum (Al) and an alloy containing Al, and the like can be given. As the alloy containing Al, an alloy containing Al and L (L represents one or more of titanium (Ti), neodymium (Nd), nickel (Ni), and lanthanum (La)), and the like, for example, an alloy containing Al and Ti or an alloy containing Al, Ni, and La, and the like can be given. Aluminum has a low specific resistance and a high light reflectance. Since aluminum is contained in the earth in a large amount and is inexpensive, the use of aluminum can reduce the manufacturing cost of the light emitting element. Further, Ag, an alloy containing silver (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)), and the like can also be used. As the alloy containing silver, for example, an alloy containing silver, palladium, and copper, an alloy containing silver and copper, an alloy containing silver and magnesium, an alloy containing silver and nickel, an alloy containing silver and gold, and an alloy containing silver and ytterbium, and the like can be given. In addition to the above-described materials, a transition metal such as tungsten, chromium (Cr), molybdenum (Mo), copper, and titanium can be used.

[0289] The light emitted from the light emitting layer is extracted through the electrode 101 and / or the electrode 102. Due to this, at least one of the electrode 101 and the electrode 102 is preferably formed using a conductive material having a function of transmitting light. As the conductive material, a conductive material having a visible light transmittance of 40% or more and 100% or less, preferably 60% or more and 100% or less, and a specific resistance of 1 x 10 -2 Ω·cm or less can be given.

[0290] The electrode 101 and the electrode 102 can also be formed using a conductive material having a function of transmitting light and a function of reflecting light. As the conductive material, a conductive material having a visible light reflectance of 20% or more and 80% or less, preferably 40% or more and 70% or less, and a specific resistance of 1 x 10 -2 Ω·cm or less can be given. For example, one or more of a metal, an alloy, and a conductive compound having conductivity can be used. Specifically, indium tin oxide (hereinafter referred to as ITO), indium tin oxide containing silicon or silicon oxide (abbreviation: ITSO), indium oxide-zinc oxide, indium oxide-tin oxide containing titanium, indium-titanium oxide, indium oxide containing tungsten oxide and zinc oxide, and the like metal oxide. A metal film having a thickness to the extent of transmitting light (preferably a thickness of 1 nm or more and 30 nm or less) can be used. As the metal, for example, an alloy of Ag, Ag and Al, Ag and Mg, Ag and Au, and Ag and Yb, and the like can be used.

[0291] In this specification and the like, a material that transmits light can be a material that transmits visible light and has conductivity. As examples of the material, there are the above-described oxide conductor typified by ITO, an oxide semiconductor, or an organic conductor containing an organic substance. As the organic conductor containing an organic substance, for example, a composite material containing a mixture of an organic compound and an electron donor (a donor), a composite material containing a mixture of an organic compound and an electron acceptor (an acceptor), or the like can be given. In addition, an inorganic carbon material such as graphene can be used. The resistivity of the material is preferably 1 x 10 5 Ωcm or less, more preferably 1 x 10 4 Ωcm or less.

[0292] In addition, the electrode 101 and / or the electrode 102 can be formed by stacking a plurality of the above-described materials.

[0293] In order to improve light extraction efficiency, a material having a higher refractive index than an electrode having a light-transmitting function can be formed in contact with the electrode. Such a material can be a conductive material or a non-conductive material as long as it has a light-transmitting function. For example, in addition to the above-described oxide conductor, an oxide semiconductor, an organic substance can be given. As the organic substance, for example, a material exemplified as a light-emitting layer, a hole-injection layer, a hole-transport layer, an electron-transport layer, or an electron-injection layer can be given. In addition, an inorganic carbon material or a thin film having a thickness to the extent of transmitting light can be used. Further, a plurality of layers each having a thickness of several nm to several tens of nm can be stacked.

[0294] When the electrode 101 or the electrode 102 is used as a cathode, a material having a small work function (3.8 eV or less) is preferably used. For example, an element belonging to Group 1 or Group 2 in the periodic table (e.g., an alkali metal such as lithium, sodium, and cesium, an alkaline earth metal such as calcium and strontium, magnesium, and the like), an alloy containing the above-described element (e.g., Ag and Mg or Al and Li), a rare earth metal such as europium (Eu) and Yb, an alloy containing the above-described rare earth metal, an alloy containing aluminum and silver, and the like can be used.

[0295] When the electrode 101 or the electrode 102 is used as an anode, a material having a large work function (4.0 eV or more) is preferably used.

[0296] Alternatively, the electrode 101 and the electrode 102 can employ a stack of a conductive material having a light-reflecting function and a conductive material having a light-transmitting function. In this case, the electrode 101 and the electrode 102 can each have a function of adjusting an optical distance so that desired light from each light-emitting layer is resonated to enhance the wavelength thereof, and thus such a structure is preferable.

[0297] As a method of forming the electrode 101 and the electrode 102, a sputtering method, an evaporation method, a printing method, a coating method, a molecular beam epitaxy (MBE) method, a CVD method, a pulsed laser deposition method, an atomic layer deposition (ALD) method, or the like can be appropriately used.

[0298] Substrate

[0299] The light-emitting element of one embodiment of the present application can be formed over a substrate of glass, plastic, or the like. The order of stacking over the substrate can be from the side of the electrode 101 or from the side of the electrode 102.

[0300] As a substrate over which the light-emitting element of one embodiment of the present application is formed, for example, glass, quartz, or plastic, or the like can be used. Alternatively, a flexible substrate can be used. The flexible substrate is a substrate which can be bent, and for example, a plastic substrate made of polycarbonate, polyarylate, or the like can be used. Alternatively, a thin film, an inorganic evaporation thin film, or the like can be used. Other materials can be used as long as they function as a support in the process of manufacturing the light-emitting element and the optical element, or as long as they have a function of protecting the light-emitting element and the optical element.

[0301] For example, in the present application and the like, a light-emitting element can be formed using various substrates. There is no particular limitation on the kind of the substrate. As examples of the substrate, a semiconductor substrate (e.g., a single crystal substrate or a silicon substrate), an SOI substrate, a glass substrate, a quartz substrate, a plastic substrate, a metal substrate, a stainless steel substrate, a substrate having a stainless steel foil, a tungsten substrate, a substrate having a tungsten foil, a flexible substrate, a bonding film, paper or a base film including a fibrous material, or the like can be used, for example. As examples of the glass substrate, barium borosilicate glass, aluminoborosilicate glass, soda lime glass, or the like can be used. As the flexible substrate, the bonding film, the base film, or the like, plastics typified by polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polytetrafluoroethylene (PTFE), or the like can be given as examples. Alternatively, resins such as an acrylic resin or the like can be given as examples. Alternatively, polypropylene, polyester, polyvinyl fluoride, or polyvinyl chloride, or the like can be given as examples. Alternatively, polyamide, polyimide, aromatic polyamide, an epoxy resin, an inorganic evaporation thin film, paper, or the like can be given as examples.

[0302] Alternatively, a flexible substrate can be used as the substrate, and the light-emitting element can be formed directly on the flexible substrate. Alternatively, a release layer can be provided between the substrate and the light-emitting element. A release layer can be used when part or all of the light-emitting element is fabricated on the release layer, and then it is separated from the substrate and transferred to another substrate. In this case, the light-emitting element can also be transferred to a substrate with low heat resistance or a flexible substrate. Note that, for example, a stacked structure of inorganic films such as tungsten film and silicon oxide film, or a structure in which a resin film such as polyimide is formed on the substrate, can be used as the release layer.

[0303] In other words, a light-emitting element can be formed on one substrate and then transferred to another substrate. Examples of substrates for which the light-emitting element is transferred, besides those mentioned above, include cellophane substrates, stone substrates, wood substrates, cloth substrates (including natural fibers (silk, cotton, linen), synthetic fibers (nylon, polyurethane, polyester) or recycled fibers (acetate fiber, cupro fiber, artificial fiber, recycled polyester), leather substrates, and rubber substrates. By using these substrates, light-emitting elements that are not easily damaged, have high heat resistance, are lightweight, or are thin can be formed.

[0304] For example, a field-effect transistor (FET) can be formed on any of the aforementioned substrates, and a light-emitting element 150 can be formed on an electrode electrically connected to the FET. Thus, an active matrix display device can be manufactured that controls the driving of the light-emitting element 150 via the FET.

[0305] The structure shown in this embodiment can be implemented by appropriately combining it with the structures shown in other embodiments.

[0306] (Implementation Method 4)

[0307] In this embodiment, refer to FIG. 2 A light-emitting element having a structure different from that shown in Embodiment 3 will be described. FIG. 2 In the middle, in having with FIG. 1A The accompanying figures show parts with the same function, using the same shading, while sometimes the figure labels are omitted. Furthermore, those with... FIG. 1A Parts with the same function are indicated by the same reference numerals, and sometimes their detailed descriptions are omitted.

[0308] <Example 2 of the structure of a light-emitting element>

[0309] FIG. 2 This is a cross-sectional schematic diagram of the light-emitting element 250.

[0310] FIG. 2The illustrated light-emitting element 250 has a plurality of light-emitting units (light-emitting unit 106 and light-emitting unit 110) between a pair of electrodes (electrode 101 and electrode 102). One of the plurality of light-emitting units preferably has a [missing information - likely a specific characteristic]. FIG. 1A The EL layer 100 shown has the same structure. That is to say, FIG. 1A The light-emitting element 150 shown preferably has one light-emitting unit, while the light-emitting element 250 preferably has multiple light-emitting units. Note that although electrode 101 is used as the anode and electrode 102 is used as the cathode in the following description of the light-emitting element 250, these functions can be interchanged in the light-emitting element 250.

[0311] exist FIG. 2 The light-emitting element 250 shown includes a stacked light-emitting unit 106 and a light-emitting unit 110, with a charge-generating layer 115 disposed between the light-emitting unit 106 and the light-emitting unit 110. Note that the light-emitting unit 106 and the light-emitting unit 110 may have the same structure or different structures. For example, the light-emitting unit 110 preferably has the same structure as the EL layer 100.

[0312] The light-emitting element 250 includes a light-emitting layer 120 and a light-emitting layer 170. The light-emitting unit 106, in addition to the light-emitting layer 170, also includes a hole injection layer 111, a hole transport layer 112, an electron transport layer 113, and an electron injection layer 114. The light-emitting unit 110, in addition to the light-emitting layer 120, also includes a hole injection layer 116, a hole transport layer 117, an electron transport layer 118, and an electron injection layer 119.

[0313] The charge generation layer 115 can have either a structure in which an acceptor substance as an electron acceptor is added to the hole transport material, or a structure in which a donor substance as an electron donor is added to the electron transport material. Furthermore, both structures can be stacked.

[0314] When the charge generation layer 115 comprises a composite material of an organic compound and a receptor substance, the composite material that can be used in the hole injection layer 111 shown in Embodiment 3 can be used as the composite material. As the organic compound, various compounds such as aromatic amine compounds, carbazole compounds, aromatic hydrocarbons, and polymers (oligomers, dendritic polymers, polymers, etc.) can be used. Preferably, the organic compound has a hole mobility of 1×10⁻⁶. -6 cm 2Vs or more. Note that a material other than these can be used as long as it is a material whose hole-transport property is higher than its electron-transport property. Since the composite of the organic compound and the acceptor substance has a high carrier-injection property and a high carrier-transport property, a low voltage driving and a low current driving can be realized. Note that when the surface of the anode side of the light-emitting unit is in contact with the charge generation layer 115, the charge generation layer 115 can also function as a hole-injection layer or a hole-transport layer of the light-emitting unit, and thus a hole-injection layer or a hole-transport layer can not be provided in the light-emitting unit. When the surface of the cathode side of the light-emitting unit is in contact with the charge generation layer 115, the charge generation layer 115 can also function as an electron-injection layer or an electron-transport layer of the light-emitting unit, and thus an electron-injection layer or an electron-transport layer can not be provided in the light-emitting unit.

[0315] The charge generation layer 115 can also have a stacked-layer structure of a layer including a composite of an organic compound and an acceptor substance and a layer including another material. For example, the charge generation layer 115 can be formed using a layer including a composite of an organic compound and an acceptor substance and a layer including a compound selected from an electron-donating substance and a high-electron-transport substance in combination. Further, the charge generation layer 115 can be formed using a layer including a composite of an organic compound and an acceptor substance and a layer including a transparent conductive film in combination.

[0316] The charge generation layer 115 interposed between the light-emitting unit 106 and the light-emitting unit 110 only needs to have a structure that injects an electron into one light-emitting unit and injects a hole into the other light-emitting unit when a voltage is applied between the electrode 101 and the electrode 102. For example, in the case where the electrode 101 is formed using a material having a higher work function than that of the electrode 102, the charge generation layer 115 injects an electron into the light-emitting unit 106 and injects a hole into the light-emitting unit 110 when a voltage is applied in such a manner that the potential of the electrode 101 is higher than that of the electrode 102. FIG. 3A

[0317] Note that the charge generation layer 115 preferably has a visible light-transmitting property (specifically, a transmittance of visible light is 40 % or more) from the viewpoint of light extraction efficiency. Further, the charge generation layer 115 functions even if its conductivity is lower than that of the pair of electrodes (the electrode 101 and the electrode 102).

[0318] By forming the charge generation layer 115 using any of the above-described materials, an increase in driving voltage at the time of stacking light-emitting layers can be suppressed.

[0319] Although the charge generation layer 115 is formed using a composite of an organic compound and an acceptor substance in the above embodiment, the present application is not limited to this. For example, the charge generation layer 115 can be formed using a composite of an organic compound and an electron-donating substance. FIG. 2 ​The light-emitting element having two light-emitting units is described, but the same structure can be applied to a light-emitting element in which three or more light-emitting units are stacked. As illustrated in the light-emitting element 250, by providing a plurality of light-emitting units between a pair of electrodes with a charge generation layer interposed therebetween, a light-emitting element that emits light with high luminance at low current density, has a long lifetime, and consumes low power can be realized.

[0320] Note that in each of the above structures, the light-emitting colors of the guest materials used for the light-emitting units 106 and 110 can be the same or different. When the light-emitting units 106 and 110 include guest materials that have a function of emitting light of the same color, the light-emitting element 250 is a light-emitting element that emits light with high luminance at a low current value, and is thus preferable. When the light-emitting units 106 and 110 include guest materials that have a function of emitting light of different colors from each other, the light-emitting element 250 emits light of a plurality of colors, and is thus preferable. At this time, when a plurality of light-emitting materials with different emission wavelengths are used for one or both of the light-emitting layer 120 and the light-emitting layer 170, light with different emission peaks is synthesized. Thus, the emission spectrum of the light-emitting element 250 has at least two peaks.

[0321] The above structure is also suitable for white light emission. White light emission can be obtained by making the light emission from the light-emitting layer 120 and the light-emitting layer 170 complementary to each other. It is particularly preferable to select guest materials in such a manner that white light emission with high color rendering properties or light emission of at least red, green, and blue is achieved.

[0322] In a light-emitting element in which three or more light-emitting units are stacked, the light-emitting colors of the guest materials used for the light-emitting units can be the same or different. In the case where the light-emitting element includes a plurality of light-emitting units that emit light of the same color, the light-emitting units can emit light of the same color with high luminance at a lower current value than light of other colors. Such a structure is suitable for adjustment of the light-emitting colors. It is particularly preferable to use guest materials that have different emission efficiencies and emit light of different colors. For example, in the case where the light-emitting element has three light-emitting units, by providing two light-emitting units including a fluorescent material that emits light of the same color and one light-emitting unit including a phosphorescent material that emits light of a color different from that of the fluorescent material, the emission intensities of fluorescent light and phosphorescent light can be adjusted. In other words, the emission intensity of each color can be adjusted in accordance with the number of light-emitting units.

[0323] In the case of using the light-emitting element described above including two fluorescent light-emitting units and one phosphorescent light-emitting unit, in order to efficiently obtain white light emission, it is preferable to use a structure in which the light-emitting units include a structure including two light-emitting units including a blue fluorescent material and one light-emitting unit including a yellow phosphorescent material; a structure including two light-emitting units including a blue fluorescent material and one light-emitting unit including a red phosphorescent material and a green phosphorescent material; or a structure including two light-emitting units including a blue fluorescent material and one light-emitting unit including a red phosphorescent material, a yellow phosphorescent material, and a green phosphorescent material.

[0324] Further, at least one of the light-emitting layer 120 and the light-emitting layer 170 can be further divided into layers and each layer can contain a different light-emitting material. That is, at least one of the light-emitting layer 120 and the light-emitting layer 170 can be formed of a plurality of layers of two or more layers. For example, in the case where a first light-emitting layer and a second light-emitting layer are stacked in this order from the hole-transport layer side to form a light-emitting layer, a material having a hole-transport property can be used for the host material of the first light-emitting layer, and a material having an electron-transport property can be used for the host 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 can be the same or different materials. In addition, the materials can have a function of emitting light of the same color or a function of emitting light of different colors. By using a plurality of light-emitting materials that emit light of different colors, white light emission with high color rendering properties can be obtained, which is composed of three primary colors or four or more light-emitting colors.

[0325] In addition, the light-emitting layer of the light-emitting unit 110 preferably contains a phosphorescent compound. When at least one of the plurality of units contains the organic compound of one embodiment of the present application, a light-emitting element with high heat resistance and high emission efficiency can be provided. Note that one embodiment can be combined as appropriate with other embodiments.

[0326] (Embodiment 5)

[0327] FIG. 3A is a top view of a light-emitting device, FIG. 3B is a cross-sectional view taken along A-B and C-D in FIG. 3A The light-emitting device includes a driver circuit portion (source side driver circuit) 601 for controlling light emission of the light-emitting element, a pixel portion 602, and a driver circuit portion (gate side driver circuit) 603, which are indicated by dotted lines. Note that a reference numeral 604 is a sealing substrate, a reference numeral 625 is a desiccant, and a reference numeral 605 is a sealing agent. The inside surrounded by the sealing agent 605 is a space 607.

[0328] Note that the lead wire 608 is a wire for transmitting a signal input to the source-side driver circuit 601 and the gate-side driver circuit 603, and receives a video signal, a clock signal, a start signal, a reset signal, and the like from a flexible printed circuit (FPC) 609 serving as an external input terminal. Although only the FPC is illustrated here, the FPC can be attached with a printed wiring board (PWB). The light-emitting device in this specification includes only the light-emitting device itself and a light-emitting device attached with the FPC or the PWB in its category.

[0329] Next, the structure of the light-emitting device will be described with reference to FIG. 3B A cross-sectional structure of the above light-emitting device will be described. A driver circuit portion and a pixel portion are formed over the element substrate 610. One pixel in the pixel portion 602 and the source-side driver circuit 601 as the driver circuit portion are illustrated here.

[0330] In the source-side driver circuit 601, a CMOS circuit in which an n-channel TFT 623 and a p-channel TFT 624 are combined is formed. The driver circuit can be formed using various CMOS circuits, PMOS circuits, or NMOS circuits. Although an integrated driver type in which the driver circuit is formed over a substrate is illustrated in this embodiment, it is not necessary to form the driver circuit over the substrate, and the driver circuit can be formed outside the substrate.

[0331] The pixel portion 602 has a plurality of pixels including a switching TFT 611, a current control TFT 612, and a first electrode 613 electrically connected to a drain of the current control TFT 612. Note that an insulator 614 is formed so as to cover an end portion of the first electrode 613. The insulator 614 can be formed using a positive photosensitive resin film.

[0332] In order to improve the coverage of a film formed over the insulator 614, the upper end portion or the lower end portion of the insulator 614 is formed into a curved surface having a curvature. For example, in the case where a photosensitive acrylic resin is used as a material of the insulator 614, it is preferable that only the upper end portion of the insulator 614 has a curved surface. The radius of curvature of the curved surface is preferably greater than or equal to 0.2 μm and less than or equal to 0.3 μm. As the insulator 614, a negative photosensitive material or a positive photosensitive material can be used.

[0333] An EL layer 616 and a second electrode 617 are formed over the first electrode 613. As a material of the first electrode 613 which serves as an anode, a material having a large work function is preferably used. For example, in addition to a single layer film of an ITO film, an indium tin oxide film containing silicon, an indium oxide film containing zinc oxide in a proportion of 2 wt% or more and 20 wt% or less, a titanium nitride film, a chromium film, a tungsten film, a Zn film, a Pt film, and the like, a stacked layer film including a titanium nitride film and a film having aluminum as its main component, and a three-layer structure film including a titanium nitride film, a film having aluminum as its main component, and a titanium nitride film, or the like can be used. When a stacked structure is employed, the wiring resistance is also low, a good ohmic contact can be obtained, and it can be used as an anode.

[0334] The EL layer 616 is formed by any of various methods such as an evaporation method using an evaporation mask, an inkjet method, a spin coating method, and the like. As other materials included in the EL layer 616, a low molecular compound or a high molecular compound (including an oligomer or a dendrimer) can be used.

[0335] As a material of the second electrode 617 which is formed over the EL layer 616 and serves as a cathode, a material having a small work function (Al, Mg, Li, Ca, or an alloy or a compound thereof, MgAg, MgIn, AlLi, and the like) is preferably used. When light generated in the EL layer 616 is made to transmit through the second electrode 617, a stacked layer including a thin metal film and a transparent conductive film (ITO, indium oxide containing zinc oxide in a proportion of 2 wt% or more and 20 wt% or less, indium tin oxide containing silicon, zinc oxide (ZnO), and the like) is preferably used as the second electrode 617.

[0336] Note that the light emitting element 618 is formed of the first electrode 613, the EL layer 616, and the second electrode 617. The light emitting element 618 preferably has the structure described in Embodiment Modes 3 and 4. In the light emitting device of this embodiment mode, a pixel portion including a plurality of light emitting elements can include both a light emitting element having the structure described in Embodiment Modes 1 and 2 and a light emitting element having a different structure.

[0337] The light emitting element 618 is provided in a space 607 surrounded by the element substrate 610, the sealing substrate 604, and the sealing material 605 by bonding the sealing substrate 604 and the element substrate 610 together with the sealing material 605. The space 607 is filled with a filler. The filler can be an inert gas (nitrogen, argon, or the like) or a resin and / or a desiccant.

[0338] As the sealing material 605, an epoxy-based resin or a glass frit is preferably used. These materials are preferably materials that transmit water or oxygen as little as possible. As the sealing substrate 604, a glass substrate, a quartz substrate, or a plastic substrate formed of a fiber-reinforced plastic (FRP), a polyvinyl fluoride (PVF), a polyester, an acrylic resin, or the like can be used.

[0339] A light-emitting device including the light-emitting element described in Embodiment 3 and Embodiment 4 can be manufactured by the above method.

[0340] Structure Example 1 of a Light-emitting Device

[0341] FIG. 4A and FIG. 4B Each of the drawings shows an example of a light-emitting device including a light-emitting element that emits white light and a color layer (color filter).

[0342] FIG. 4A 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 driver circuit portion 1041, a first electrode 1024W, 1024R, 1024G, 1024B of a light-emitting element, a separation wall 1026, an EL layer 1028, a second electrode 1029 of a light-emitting element, a sealing substrate 1031, a sealing material 1032, and the like are shown.

[0343] In FIG. 4A , FIG. 4B A color layer (a red color layer 1034R, a green color layer 1034G, and a blue color layer 1034B) is provided on a transparent substrate 1033. In addition, a black layer (black matrix) 1035 can be provided. The transparent substrate 1033 provided with the color layer and the black layer is aligned and fixed to the substrate 1001. Note that the color layer and the black layer are covered with a cover layer 1036. In FIG. 4A In this embodiment, light emitted from some light-emitting layers does not pass through the color layer, and light emitted from the other light-emitting layers passes through the color layer. Since the light that does not pass through the color layer is white and the light that passes through any of the color layers is red, blue, or green, an image can be represented with pixels of four colors.

[0344] FIG. 4B An example in which a red color layer 1034R, a green color layer 1034G, and a blue color layer 1034B are formed between the gate insulating film 1003 and the first interlayer insulating film 1020 is shown. As FIG. 4B indicated in

[0345] Although the light-emitting device described above has a structure in which light is extracted from the side of the substrate 1001 on which a TFT is formed (bottom emission type), it can have a structure in which light is extracted from the side of the sealing substrate 1031 (top emission type).

[0346] Structure Example 2 of a Light-emitting Device

[0347] FIG. 5 This is a cross-sectional view of a light-emitting device with a top-emitting structure. In this case, a light-blocking substrate can be used for substrate 1001. The processes up to fabricating the connecting electrode that connects the TFT and the anode of the light-emitting element are performed in the same manner as for a light-emitting device with a bottom-emitting structure. Then, a third interlayer insulating film 1037 is formed to cover electrode 1022. This insulating film may also have a planarization function. The third interlayer insulating film 1037 can be formed using the same material as the second interlayer insulating film 1021 or various other materials.

[0348] Although the lower electrodes 1025W, 1025R, 1025G, and 1025B of the light-emitting element are all anodes here, they can also be cathodes. Additionally, in FIG. 5 In the light-emitting device with a top-emitting structure shown, the lower electrodes 1025W, 1025R, 1025G, and 1025B are preferably reflective electrodes. Note that the second electrode 1029 preferably has the function of emitting light and allowing light to pass through. A microcavity structure is preferably used between the second electrode 1029 and the lower electrodes 1025W, 1025R, 1025G, and 1025B, thereby amplifying light of a specific wavelength. The EL layer 1028 is formed with the same structure as described in Embodiment 2, and employs a method that enables white light emission.

[0349] exist FIG. 4A , FIG. 4B and FIG. 5 In this context, a white-emitting EL layer structure can be achieved by using multiple light-emitting layers or multiple light-emitting units. Note that the structure for obtaining white light emission is not limited to this.

[0350] In adopting such FIG. 5 In the case of the top-emitting structure shown, sealing can be achieved using a sealing substrate 1031 provided with color layers (red color layer 1034R, green color layer 1034G, and blue color layer 1034B). The sealing substrate 1031 may also have a black layer (black matrix) 1035 located between pixels. The color layers (red color layer 1034R, green color layer 1034G, and blue color layer 1034B) and the black layer (black matrix) may also be covered by a capping layer. Note that a light-transmitting substrate is used as the sealing substrate 1031.

[0351] Although an example of full-color display using four colors—red, green, blue, and white—is shown here, it is not limited to this. Full-color display can also be achieved using three colors—red, green, and blue, or four colors—red, green, blue, and yellow.

[0352] The light emitting device including the light emitting element described in Embodiment 3 and Embodiment 4 can be obtained by the above method.

[0353] Note that this embodiment can be combined with other embodiments as appropriate.

[0354] (Embodiment 6)

[0355] In this embodiment, an electronic device of one embodiment of the present application is described.

[0356] With one embodiment of the present application, an electronic device with a flat surface and high reliability can be manufactured. With one embodiment of the present application, an electronic device with a curved surface and high reliability can be manufactured. With one embodiment of the present application, an electronic device with flexibility and high reliability can be formed.

[0357] Examples of electronic devices include television devices, desktop or notebook personal computers, displays for computers and the like, digital cameras, digital video cameras, digital photo frames, mobile phones, portable game machines, portable information terminals, sound reproduction devices, large game machines such as pachinko machines, and the like.

[0358] The light emitting device of one embodiment of the present application can achieve high visibility regardless of the intensity of external light. Thus, the light emitting device of one embodiment of the present application can be appropriately applied to portable electronic devices, wearable electronic devices (wearable devices), electronic book readers, and the like.

[0359] FIG. 6A and FIG. 6B The portable information terminal 900 illustrated in FIG. 8A includes a housing 901, a housing 902, a display portion 903, a hinge portion 905, and the like.

[0360] The housing 901 and the housing 902 are connected to each other with the hinge portion 905. The portable information terminal 900 can be unfolded from a folded state (FIG. 8A) to an unfolded state (FIG. 8B). FIG. 6A As illustrated in FIG. 8B, the display portion 903 is provided across the housing 901 and the housing 902 connected by the hinge portion 905. FIG. 6B Thus, the portability of the portable information terminal 900 is good when carried, and the visibility is high when used because of the large display area.

[0361] The display portion 903 is provided across the housing 901 and the housing 902 connected by the hinge portion 905 in the portable information terminal 900.

[0362] The light emitting device manufactured using one embodiment of the present application can be used for the display portion 903. Thus, the portable information terminal can be manufactured with high yield.

[0363] The display section 903 can display at least one of a file, a still image, and a moving image. When a file is displayed on the display section, the portable information terminal 900 can be used as an electronic book reader.

[0364] When the portable information terminal 900 is unfolded, the display section 903 is largely bent. For example, the display section 903 can be held in a manner including a portion bent with a radius of curvature of 1 mm or more and 50 mm or less, preferably 5 mm or more and 30 mm or less. Pixels are continuously arranged across the housings 901 and 902, so that a portion of the display section 903 can display an image in a bent state.

[0365] The display section 903 is used as a touch panel and can be operated by a finger or a stylus pen or the like.

[0366] The display section 903 is preferably formed using one flexible display. Thereby, a continuous image can be displayed across the housings 901 and 902. Note that the housings 901 and 902 can each be provided with a display.

[0367] In order to avoid that an angle formed by the housings 901 and 902 when the portable information terminal 900 is unfolded exceeds a predetermined angle, the hinge section 905 preferably has a locking mechanism. For example, an angle at which the housings 901 and 902 are in a locked state (cannot be further opened) is preferably 90° or more and less than 180°, typically, can be 90°, 120°, 135°, 150°, or 175°, or the like. At this time, convenience, safety, and reliability of the portable information terminal 900 can be improved.

[0368] When the hinge section 905 has a locking mechanism, an excessive force is not applied to the display section 903, so that damage to the display section 903 can be prevented. Thereby, a portable information terminal with high reliability can be realized.

[0369] The housings 901 and 902 can also include a power button, an operation button, an external connection port, a speaker, a microphone, or the like.

[0370] Either of the housings 901 and 902 is provided with a wireless communication module, and data transmission and reception can be performed through a computer network such as the Internet, a local area network (LAN), Wi-Fi (registered trademark), or the like.

[0371] FIG. 6C The illustrated portable information terminal 910 includes a housing 911, a display section 912, an operation button 913, an external connection port 914, a speaker 915, a microphone 916, a camera 917, and the like.

[0372] The light-emitting device manufactured using the embodiment of the present application can be used for the display portion 912. Thus, the portable information terminal can be manufactured with high yield.

[0373] The portable information terminal 910 includes a touch sensor in the display portion 912. By touching the display portion 912 with a finger or a stylus or the like, various operations such as making a call or inputting a character can be performed.

[0374] The power can be turned on or off with the operation button 913. Further, the type of image displayed on the display portion 912 can be switched, for example, the composition screen of an e-mail can be switched to a home menu screen with the operation button 913.

[0375] When a detection device such as a gyro sensor or an acceleration sensor is provided inside the portable information terminal 910, the display direction of the display portion 912 can be automatically switched by judging the direction of the portable information terminal 910 (whether the portable information terminal 910 is arranged in a portrait orientation or a landscape orientation). Alternatively, the display direction can be switched by touching the display portion 912, operating the operation button 913, or inputting a sound with the microphone 916.

[0376] The portable information terminal 910 is used as one or a plurality of a telephone, a notebook, and an information reading system, for example. Specifically, the portable information terminal 910 can be used as a smartphone. The portable information terminal 910 can execute various application programs such as a mobile phone, an e-mail, a reading and editing of an article, a music play, a moving picture play, Internet communication, a computer game, and the like, for example.

[0377] FIG. 6D The camera 920 includes a housing 921, a display portion 922, an operation button 923, a shutter button 924, and the like. Further, the camera 920 is provided with a detachable lens 926.

[0378] The light-emitting device manufactured using the embodiment of the present application can be used for the display portion 922. Thus, the camera can be manufactured with high yield.

[0379] Here, although the lens 926 of the camera 920 is detachable from the housing 921, the lens 926 can be included in the housing 921.

[0380] By pressing the shutter button 924, the camera 920 can take a still image or a moving image. Further, the camera 920 can take an image by touching the display portion 922 having a touch panel function.

[0381] Note that the camera 920 can further include a flash and a viewfinder, and the like. Further, these components can be included in the housing 921.

[0382] FIG. 7A to FIG. 7E Electronic devices are shown. These electronic devices each include a housing 9000, a display portion 9001, a speaker 9003, an operation key 9005 (including a power source switch or an operation switch), a connection terminal 9006, a sensor 9007 (a sensor having a function of measuring a force, a displacement, a position, a speed, an acceleration, an angular velocity, an angular frequency, a distance, light, liquid, a magnetism, a temperature, a chemical substance, a sound, a time, a hardness, an electric field, an electric current, an electric power, a radiation line, a flow rate, a humidity, an inclination, a vibration, a smell, or an infrared ray), a microphone 9008, and the like.

[0383] The light-emitting device manufactured using the embodiment of the present application can be used for the display portion 9001. Thus, the electronic device can be manufactured with high yield.

[0384] FIG. 7A to FIG. 7E The electronic devices shown can have various functions, such as display of various information (still images, moving images, text images, and the like) on the display portion, a touch panel, display of a calendar, a date, or time, and the like, processing by use of various software (programs), wireless communication, connection to a variety of computer networks using a wireless communication function, transmission or reception of various data using the wireless communication function, reading of a program or data stored in a recording medium to display on the display portion, and the like. Note that, FIG. 7A to FIG. 7E The functions of the electronic devices shown are not limited to the above functions, and the electronic devices can have other functions.

[0385] FIG. 7A A perspective view of a portable information terminal 9200 which is a wristwatch type is shown. FIG. 7B A perspective view of a portable information terminal 9201 which is a wristwatch type is shown.

[0386] FIG. 7A The portable information terminal 9200 shown can execute various application programs such as a mobile phone, an electronic mail, reading and editing of an article, music playback, Internet communication, a computer game, and the like. In addition, the display surface of the display portion 9001 is curved, and an image can be displayed along the curved display surface. The portable information terminal 9200 can perform close proximity wireless communication based on a communication standard. For example, hands-free calling can be performed by communicating with a headset which can perform wireless communication. In addition, the portable information terminal 9200 includes the connection terminal 9006, and data exchange can be performed directly with another information terminal by a connector. In addition, charging can be performed through the connection terminal 9006. Note that, charging operation can be performed by wireless power supply without the connection terminal 9006.

[0387] Unlike the portable information terminal shown, FIG. 7A FIG. 7B ​The display surface of the display portion 9001 of the portable information terminal 9201 illustrated is not curved. Further, the shape of the display portion of the portable information terminal 9201 is not rectangular (in this embodiment, a circular shape). FIG. 7B

[0388] FIG. 7C to FIG. 7E is a perspective view of a portable information terminal 9202 which is foldable. FIG. 7C is a perspective view illustrating a state in which the portable information terminal 9202 is unfolded. FIG. 7D is a perspective view illustrating a state in which the portable information terminal 9202 is in an unfolded state or a folded state. FIG. 7E is a perspective view illustrating a state in which the portable information terminal 9202 is folded.

[0389] The portable information terminal 9202 is good in portability in a folded state and has high display overview in an unfolded state because a large display region is seamlessly connected. The display portion 9001 included in the portable information terminal 9202 is supported by three housings 9000 which are connected by hinges 9055. The portable information terminal 9202 can be reversibly changed from an unfolded state to a folded state by bending two housings 9000 with the hinges 9055. For example, the portable information terminal 9202 can be bent at a curvature radius of 1 mm or more and 150 mm or less.

[0390] Note that this embodiment mode can be combined as appropriate with another embodiment mode.

[0391] (Embodiment 7)

[0392] In this embodiment, examples in which a light-emitting element of one embodiment of the present application is applied to various electronic devices and lighting devices are described with reference to FIG. 8A to FIG. 8C and FIG. 9

[0393] By forming a light-emitting element of one embodiment of the present application over a substrate having flexibility, an electronic device or a lighting device including a light-emitting region having a curved surface can be achieved.

[0394] Further, a lighting device using a light-emitting element of one embodiment of the present application can be used for lighting of a vehicle, which is provided in a windshield, a ceiling, or the like.

[0395] FIG. 8A is a perspective view of one face of a multifunctional terminal 3500, FIG. 8B is a perspective view of another face of the multifunctional terminal 3500. In the multifunctional terminal 3500, a frame 3502 is assembled with a display portion 3504, a camera 3506, lighting 3508, and the like. A light-emitting device of one embodiment of the present application can be used for the lighting 3508. ​​

[0396] The illumination 3508 including the light-emitting device of one embodiment of the present application is used as a surface light source. Thus, unlike a point light source typified by an LED, light emission with low directivity can be obtained. For example, in the case of using the illumination 3508 and the camera 3506 in combination, photographing can be performed using the camera 3506 while the illumination 3508 is lit or flashed. Since the illumination 3508 has the function of a surface light source, a photo as if taken under natural light can be obtained.

[0397] Note that, FIG. 8A and FIG. 8B The multifunctional terminal 3500 illustrated in FIG. 34A and the electronic device illustrated in FIG. 34B can have a variety of functions similarly. FIG. 7A to FIG. 7C

[0398] In addition, a speaker, a sensor having a function of measuring or sensing a force, a displacement, a position, a velocity, an acceleration, an angular velocity, a rotational frequency, a distance, light, liquid, magnetism, temperature, a chemical substance, a sound, time, hardness, an electric field, an electric current, an electric power, a radiation, a flow rate, humidity, inclination, vibration, an odor, or infrared rays, a microphone, or the like can be provided in the inside of the housing 3502. Further, by providing a detection device having a sensor that detects inclination such as a gyro sensor and an acceleration sensor in the inside of the multifunctional terminal 3500, the direction (portrait or landscape) of the multifunctional terminal 3500 can be determined, and switching of the screen display of the display portion 3504 can be automatically performed.

[0399] In addition, the display portion 3504 can be used as an image sensor. For example, by touching the display portion 3504 with a palm or a finger, a palm print, a fingerprint, or the like can be photographed, and individual identification can be performed. In addition, by providing a back light or a light source that emits near-infrared light in the display portion 3504, a finger vein, a palm vein, or the like can be photographed. Note that the light-emitting device of one embodiment of the present application can be applied to the display portion 3504.

[0400] FIG. 8C A perspective view of a security light 3600 is shown. The light 3600 includes an illumination 3608 on the outside of a housing 3602, and the housing 3602 is assembled with a speaker 3610 and the like. The light-emitting element of one embodiment of the present application can be used for the illumination 3608.

[0401] ​The lamp 3600 illuminates, for example, when the lighting 3608 is grasped or held. Additionally, an electronic circuit capable of controlling the illumination mode of the lamp 3600 can be provided inside the housing 3602. This electronic circuit could be, for example, a circuit capable of achieving single or intermittent multiple illuminations, or a circuit capable of adjusting the amount of light emitted by controlling the current value. Furthermore, a circuit that emits a loud alarm sound from the speaker 3610 while the lighting 3608 is illuminating can also be assembled.

[0402] Because the Light 3600 can emit light in all directions, it can emit light or produce light and sound to intimidate criminals. Additionally, the Light 3600 can include cameras such as digital still cameras with video recording capabilities.

[0403] FIG. 9 This is an example of using a light-emitting element in an indoor lighting device 8501. Furthermore, because the light-emitting element can be made large-area, large-area lighting devices can also be formed. Additionally, a lighting device 8502 with a curved light-emitting area can be formed by using a frame with a curved surface. The light-emitting element shown in this embodiment is thin-film, so there is a high degree of freedom in the design of the frame. Therefore, lighting devices that can accommodate various designs can be formed. Furthermore, a large lighting device 8503 can also be installed on an indoor wall. Additionally, touch sensors can be provided in lighting devices 8501, 8502, and 8503 to turn the power on or off.

[0404] Additionally, by using the light-emitting element on one side of the table surface, a lighting device 8504 that functions as a table can be provided. Furthermore, by using the light-emitting element as part of other furniture, a lighting device that functions as furniture can be provided.

[0405] As described above, by applying the light-emitting element according to one aspect of the present invention, lighting devices and electronic devices can be obtained. Note that the lighting devices and electronic devices are not limited to those shown in this embodiment; the light-emitting device can be applied to lighting devices and electronic devices in various fields.

[0406] The structure shown in this embodiment can be implemented by appropriately combining it with the structures shown in other embodiments.

[0407] [Example 1]

[0408] In this embodiment, the synthesis method and characteristics of 3,8-bis[3-(dibenzothiophene-4-yl)phenyl]benzofurano[2,3-b]pyrazine (abbreviated as: 3,8mDBtP2Bfpr) (structural formula (100)), one of the compounds represented by general formula (G0) according to one embodiment of the present invention, are described.

[0409] <Synthesis example 1>

[0410] <Step 1: Synthesis of 6-chloro-3-(5-chloro-2-methoxyphenyl)pyrazin-2-amine>

[0411] Into a three-necked flask equipped with a reflux tube, 3-bromo-6-chloropyrazin-2- amine 1.00 g, 5-chloro-2-methoxyphenylboronic acid 0.90 g, potassium fluoride 0.93 g and tetrahydrofuran 17 mL were placed, and the inside thereof was replaced with nitrogen. The mixture in the flask was stirred under reduced pressure to be degassed, and then tris(dibenzylideneacetone)dipalladium(0) 0.088 g and tri-tert-butylphosphine 0.8 mL were added. Stirring was performed at 80°C for 40 hours to allow the reaction to proceed. After the prescribed time had elapsed, the obtained mixture was suction-filtered, and the filtrate was concentrated. The obtained residue was purified by silica gel column chromatography with dichloromethane as the developing solvent, and the obtained filtrate was concentrated, whereby 6-chloro-3-(5-chloro-2-methoxyphenyl)pyrazin-2-amine, the object substance, was obtained as a yellowish white powder at a yield of 71% (0.92 g). The synthesis scheme of Step 1 is shown in (a-1) below.

[0412] ( a -1)

[0413]

[0414] <Step 2: Synthesis of 3,8-dichlorobenzo[f]pyrazino[2,3-b]pyrazine>

[0415] Into a three-necked flask, 6-chloro-3-(5-chloro-2-methoxyphenyl)pyrazin-2-amine 1.37 g obtained by the above Step 1, anhydrous tetrahydrofuran 16 mL and glacial acetic acid 32 mL were placed, and the inside thereof was replaced with nitrogen. After the flask was cooled to -10°C, tert-butyl nitrite 1.9 mL was dropped, and stirring was performed at -10°C for 1 hour and at 0°C for 20 hours. After the prescribed time had elapsed, water 100 mL was added to the obtained suspension, and suction filtration was performed. The obtained solid was dissolved in dichloromethane, filtered using a filter aid in which diatomaceous earth, alumina and diatomaceous earth were sequentially layered, and the filtrate was concentrated, whereby 3,8-dichlorobenzo[f]pyrazino[2,3-b]pyrazine, the object substance, was obtained as a white solid at a yield of 70% (0.87 g). The synthesis scheme of Step 2 is shown in (a-2) below.

[0416] (a-2)

[0417]

[0418] <Step 3: Synthesis of 3,8-bis[3-(dibenzothiophen-4-yl)phenyl]benzo[f]pyrazino[2,3-b]pyrazine (abbreviation: 3,8mDBtP2Bfpr)>

[0419] Next, 0.87 g of 3,8-dichlorobenzofurano[2,3-b]pyrazine, 2.41 g of 3-(4-dibenzothiophene)phenylboronic acid, 4.57 g of tripotassium phosphate, 29 mL of diethylene glycol dimethyl ether, and 2.0 mL of tert-butanol obtained in step 2 above were placed in a three-necked flask, and the inside was purged with nitrogen. The mixture in the flask was stirred under reduced pressure to degas, and then 0.016 g of palladium(II) acetate and 0.054 g of bis(1-adamantyl)-n-butylphosphine (CataCXiumA) were added. The mixture was stirred at 140 °C for 8 hours to allow the reaction to proceed. After the specified time, the resulting suspension was filtered and washed with water and ethanol. After purification of the obtained solid by silica gel column chromatography with toluene as the developing solvent, recrystallization was performed using a mixed solvent of toluene and hexane, thereby obtaining 1.25 g of the target compound 3,8mDBtP2Bfpr as a yellowish-white solid in 52% yield. The synthetic scheme for step 3 is shown below (a-3).

[0420] ( a -3)

[0421]

[0422] Then, 1.14 g of the yellowish-white solid was purified by gradient sublimation. The sublimation purification conditions were as follows: pressure 2.6 Pa, argon gas flow rate 5 mL / min, and heating of the yellowish-white solid at 350 °C. After sublimation purification, 0.99 g of the target yellowish-white solid was obtained with a recovery rate of 87%.

[0423] Nuclear magnetic resonance (NMR) was performed on the obtained solid. 1 The analysis results are shown below (H NMR).

[0424] 1 H-NMR.δ(CD2Cl2): 7.49-7.54(m, 4H), 7.62-7.65(m, 4H), 7.69(t, 1H), 7.74(t, 1H), 7.80-7.84(m, 3H), 7 .89-7.91 (m, 3H), 8.03 (dd, 1H), 8.14 (s, 1H), 8.23-8.28 (m, 5H), 8.56 (d, 1H), 8.59 (s, 1H), 9.26 (s, 1H).

[0425] FIG. 10A and FIG. 10B The obtained solid is shown 1 H NMR spectrum. Note. FIG. 10B for FIG. 10AA magnified view showing the concentration range of 7.0 ppm to 9.6 ppm. The results indicate that the target compound 3,8mDBtP2Bfpr was obtained.

[0426] <3.8mDBtP2Bfpr characteristics>

[0427] then, FIG. 11 The absorption and emission spectra of 3,8mDBtP2Bfpr in toluene solution are shown.

[0428] Absorption spectra were measured using a UV-Vis spectrophotometer (V550 model, manufactured by Nippon Spectrophotometer Co., Ltd.). The absorption spectrum of 3,8mDBtP2Bfpr in a toluene solution was determined as follows: a toluene solution of 3,8mDBtP2Bfpr was placed in a quartz dish. The absorption spectrum of the solvent (toluene) used in the quartz dish was subtracted from this absorption spectrum, and the resulting absorption spectrum is shown in the attached figure. When measuring the emission spectrum, a PL-EL measuring apparatus (manufactured by Hamamatsu Photonics Co., Ltd., Japan) was used. The emission spectrum of 3,8mDBtP2Bfpr in a toluene solution was measured by placing a toluene solution of 3,8mDBtP2Bfpr in a quartz dish.

[0429] like FIG. 11 As shown, 3,8mDBtP2Bfpr in toluene solution has absorption spectrum peaks near 283nm and 352nm, and emission spectrum peaks near 386nm (excitation wavelength: 333nm).

[0430] Next, the absorption and emission spectra of the 3.8 mDbtP2Bfpr solid film were measured. The solid film was fabricated on a quartz substrate by vacuum evaporation. A UV-Vis spectrophotometer (U4100 model, manufactured by Mabuchi S&T Inc.) was used to measure the absorption spectrum. A fluorescence spectrophotometer (FS920 model, manufactured by Hamamatsu Photonics Co., Ltd., Japan) was used to measure the emission spectrum. FIG. 12 The results of the absorption and emission spectra of the obtained solid thin film are shown. FIG. 12 In the diagram, the horizontal axis represents wavelength, and the vertical axis represents absorption intensity and luminescence intensity.

[0431] like FIG. 12 As shown, the solid film of 3,8mDBtP2Bfpr has absorption spectrum peaks near 247nm and 354nm, and emission spectrum peaks near 437nm (excitation wavelength: 355nm).

[0432] [Example 2]

[0433] In the present embodiment, a method for synthesizing 2,8-bis[3-(dibenzothiophen-4-yl)phenyl]benzofuro[2,3-b]pyrazine (abbreviation: 2,8mDBtP2Bfpr) (Formula (101)) which is one of the compounds represented by General Formula (G0) of one embodiment of the present application and characteristics of the compound are described.

[0434] <Synthesis Example 2>

[0435] <Step 1: Synthesis of 5-chloro-3-(5-chloro-2-methoxyphenyl)pyrazin-2-amine>

[0436] A three-necked flask equipped with a reflux tube was charged with 3-bromo-5-chloropyrazin-2-amine 2.48 g, 5-chloro-2-methoxyphenylboronic acid 2.19 g, potassium fluoride 2.26 g, and tetrahydrofuran 43 mL, and the inside thereof was replaced with nitrogen. The mixture in the flask was stirred under reduced pressure to be degassed, and then tris(dibenzylideneacetone)dipalladium(0) 0.44 g and tri-tert-butylphosphine 4.0 mL were added. Stirring was performed at 80 °C for 42 hours to allow the reaction to proceed. After the elapse of the prescribed time, the obtained mixture was suction-filtered, and the filtrate was concentrated. The obtained residue was purified by silica gel column chromatography with toluene: ethyl acetate = 10: 1 as a developing solvent, whereby the desired product 2,8-bis[3-(dibenzothiophen-4-yl)phenyl]benzofuro[2,3-b]pyrazine 1.00 g was obtained at a yield of 31 %. The following (b-1) shows a synthesis scheme of Step 1.

[0437] (b-1)

[0438]

[0439] <Step 2: Synthesis of 2,8-dichlorobenzofuro[2,3-b]pyrazine>

[0440] Next, 5-chloro-3-(5-chloro-2-methoxyphenyl)pyrazin-2-amine 1.00 g obtained through Step 1 described above, anhydrous tetrahydrofuran 12 mL, and glacial acetic acid 24 mL were charged into a three-necked flask, and the inside thereof was replaced with nitrogen. After the flask was cooled to -10 °C, tert-butyl nitrite 1.3 mL was dropped, and stirring was performed at -10 °C for 1 hour and at 0 °C for 20 hours. After the elapse of the prescribed time, water 100 mL was added to the obtained suspension, and suction filtration was performed. The obtained solid was purified by silica gel column chromatography with dichloromethane as a developing solvent, whereby the desired product 2,8-dichlorobenzofuro[2,3-b]pyrazine 0.66 g was obtained at a yield of 75 %. The following (b-2) shows a synthesis scheme of Step 2.

[0441] (b-2)

[0442]

[0443] Step 3: Synthesis of 2,8-bis[3-(dibenzothiophen-4-yl)phenyl]benzofuro[2,3-b]pyrazine (abbreviated as: 2,8mDBtP2Bfpr)

[0444] Next, 2,8-dichlorobenzofuro[2,3-b]pyrazine 0.66 g, 3-(4-dibenzothiophen)phenylboronic acid 1.90 g, potassium phosphate tribasic 3.59 g, diethylene glycol dimethyl ether 23 mL, and t-butyl alcohol 1.6 mL obtained by the above-described Step 2 were put in a three-necked flask, and the inside thereof was replaced with nitrogen. The mixture in the flask was stirred under reduced pressure to be degassed, and then palladium (II) acetate 0.026 g and bis(1-adamantyl)-n-butylphosphine (abbreviated as: CataCXium A) 0.086 g were added, and stirring was performed at 140°C for 15 hours to cause a reaction. After the prescribed time, the obtained suspension was suction-filtered, and washed with water and ethanol. The obtained solid was purified by silica gel column chromatography with toluene as a developing solvent, and then recrystallized using a mixed solvent of toluene and hexane, whereby 2,8mDBtP2Bfpr, a yellow-white solid of the object substance, was obtained at a yield of 32% (0.61 g). The following (b-3) shows a synthesis scheme of Step 3.

[0445] (b-3)

[0446]

[0447] Next, the yellow-white powder solid 0.60 g was subjected to sublimation purification twice using gradient sublimation. The sublimation purification conditions were as follows: the pressure was 2.7 Pa, the argon gas flow rate was 5 mL / min, and the yellow-white powder solid was heated at 355°C. After the sublimation purification, a yellow-white solid of the object substance was obtained at a recovery rate of 73% (0.44 g).

[0448] The obtained solid was subjected to nuclear magnetic resonance (1H NMR), and the analysis results are shown below. 1 H NMR), and the analysis results are shown below.

[0449] 1 H-NMR. δ (CD2Cl2): 7.32 (s, 1H), 7.46-7.52 (m, 4H), 7.61-7.64 (m, 4H), 7.68 (t, 1H), 7.74 (t, 1H), 7.79-7.90 (m, 5H), 8.05 (dd, 1H), 8.13 (s, 1H), 8.22-8.26 (m, 5H), 8.56 (s, 1H), 8.62 (d, 1H), 8.95 (s, 1H).

[0450] FIG. 13A andFIG. 13B The obtained solid was shown to be 2,8mDBtP2Bfpr by 1 H NMR spectrum. Note that, FIG. 13B was FIG. 13A a magnified view of the range from 7.0 ppm to 9.0 ppm in the 1H NMR spectrum. From the measurement result, it was found that the object 2,8mDBtP2Bfpr was obtained.

[0451] <Properties of 2,8mDBtP2Bfpr>

[0452] Next, FIG. 14 The absorption spectrum and the emission spectrum of 2,8mDBtP2Bfpr in toluene solution were shown. Note that the measurement method of the absorption spectrum and the emission spectrum of 2,8mDBtP2Bfpr in toluene solution was the same as in Embodiment 1.

[0453] As shown in FIG. 14 , 2,8mDBtP2Bfpr in toluene solution had a peak of the absorption spectrum near 283 nm and 336 nm, and had a peak of the emission spectrum near 383 nm (excitation wavelength: 338 nm).

[0454] [Embodiment 3]

[0455] In this embodiment, a manufacturing example of a light-emitting element including an organic compound of one embodiment of the present application and properties of the light-emitting element are described. The cross-sectional view of the element manufactured in this embodiment is the same as that of FIG. 1A . Table 1 shows details of the element structure. Note that the structures and abbreviations of the compounds used are shown below. Note that the above-described embodiments can be referred to for other organic compounds.

[0456]

[0457] [Table 1]

[0458]

[0459]

[0460] Manufacture of Light-Emitting Element 1

[0461] As the electrode 101, an ITSO film having a thickness of 70 nm was formed over the substrate 200. The electrode area of the electrode 101 was 4 mm 2 (2 mm x 2 mm).

[0462] As the hole injection layer 111, 4,4',4"-(benzene-1,3,5-triyl)tris(dibenzothiophene) (abbreviation: DBT3P-II) and molybdenum trioxide (Mo03) were co-evaporated over the electrode 101 to a thickness of 60 nm with a weight ratio (DBT3P-II: Mo03) of 1:0.5.

[0463] As the hole transport layer 112, 4-phenyl-4'-(9-phenylfluorene-9-yl)triphenylamine (abbreviation: BPAFLP) was deposited over the hole injection layer 111 to a thickness of 20 nm.

[0464] Next, as the light-emitting layer 140(1), 3,8mDBtP2Bfpr, N-(1,1'-biphenyl-4-yl)-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9H-fluorene-2-amine (abbreviation: PCBBiF), and bis[2-(6-phenyl-4-pyrimidyl-κN 3 )phenyl-κC](2,4-pentanedionato-κ 2 O, O')iridium(III) (abbreviation: Ir(dppm)2(acac)) were co-deposited over the hole transport layer 112 to a thickness of 20 nm with a weight ratio (3,8mDBtP2Bfpr: PCBBiF: Ir(dppm)2(acac)) of 0.7:0.3:0.05. Next, as the light-emitting layer 140(2), the above materials were co-deposited to a thickness of 20 nm with a weight ratio (3,8mDBtP2Bfpr: PCBBiF: Ir(dppm)2(acac)) of 0.8:0.2:0.05. Note that Ir(dppm)2(acac) is a guest material that emits phosphorescent light in the light-emitting layer 140.

[0465] As the electron transport layer 118, 3,8mDBtP2Bfpr and bathophenanthroline (abbreviation: BPhen) were sequentially deposited over the light-emitting layer 140 to thicknesses of 20 nm and 20 nm, respectively. Next, as the electron injection layer 119, LiF was deposited over the electron transport layer 118 to a thickness of 1 nm.

[0466] As the electrode 102, aluminum (Al) was formed over the electron injection layer 119 to a thickness of 200 nm.

[0467] Next, the substrate 220 was fixed to the substrate 200 over which the organic material was formed, using a sealant for organic EL in a glove box filled with nitrogen, whereby the light-emitting element 1 was sealed. Specifically, the sealant was applied to the periphery of the organic material formed in the substrate 200, the substrate 200 and the substrate 220 were attached to each other, and the sealant was cured with irradiation of ultraviolet light at 6 J / cm 2The light-emitting element 1 is obtained by irradiating it with ultraviolet light at a wavelength of 365 nm and then heating it at 80°C for 1 hour.

[0468] Characteristics of light-emitting elements

[0469] FIG. 15 The current efficiency-brightness characteristics of the manufactured light-emitting element 1 are shown. FIG. 16 The current density-voltage characteristics are shown. FIG. 17 The external quantum efficiency-luminance characteristics are shown. The characteristics of the light-emitting element 1 were measured at room temperature (in an atmosphere maintained at 23°C). FIG. 18 It shows 2.5 mA / cm 2 The current density is used to determine the electroluminescence spectrum when current flows through the light-emitting element 1. The measurement is performed at room temperature.

[0470] Table 2 shows the values ​​for 1000 cd / m³. 2 The characteristics of the nearby light-emitting element 1.

[0471] [Table 2]

[0472]

[0473] like FIG. 15 , FIG. 17 As shown in Table 2, light-emitting element 1 exhibits high current efficiency and external quantum efficiency. Furthermore, even on the high-brightness side, the efficiency reduction (attenuation) of light-emitting element 1 is minimal, which is an excellent result.

[0474] Additionally, as shown in Table 2, the light-emitting element 1 has a density of 1000 cd / m². 2 The nearby drive voltage is low at 2.6V, indicating good power efficiency.

[0475] like FIG. 18 As shown, light-emitting element 1 emits orange light, with a peak wavelength of 584 nm and a full width at half maximum (FWHM) of 73 nm in its electroluminescence spectrum. The obtained electroluminescence spectrum indicates that the light emission originates from the guest material Ir(dppm)₂(acac).

[0476] <Reliability of Light-Emitting Elements>

[0477] Next, a constant current drive test at 2mA was performed on the light-emitting element 1. FIG. 19 The results are shown. From FIG. 19 It can be seen that the brightness half-life of light-emitting element 1 exceeds 1000 hours, and light-emitting element 1 has very high reliability.

[0478] As described above, by using the compound of one embodiment of the present application for the light-emitting layer, a light-emitting element exhibiting high emission efficiency can be manufactured. Furthermore, a light-emitting element with low driving voltage and low power consumption can be manufactured. Furthermore, a light-emitting element with high reliability can be manufactured.

[0479] [Example 4]

[0480] In this embodiment, a manufacturing example of a light-emitting element including an organic compound of one embodiment of the present application, which is different from that of Example 3, and characteristics of the light-emitting element are described. The cross-sectional view of the element manufactured in this embodiment is similar to that of FIG. 1A Table 3 shows details of the element structures. Note that the structures and abbreviations of the compounds used are shown below. Note that the other organic compounds can be referred to those described in the above embodiments.

[0481]

[0482] [Table 3]

[0483]

[0484] Manufacture of Light-Emitting Element 2

[0485] As the electrode 101, an ITSO film with a thickness of 70 nm was formed over the substrate 200. The electrode area of the electrode 101 was 4 mm 2 (2 mm x 2 mm).

[0486] As the hole-injection layer 111, DBT3P-II and molybdenum oxide (MoO3) were co-evaporated over the electrode 101 so that the thicknesses thereof were 45 nm and the weight ratio (DBT3P-II: MoO3) was 1:0.5.

[0487] As the hole-transport layer 112, PCCP was evaporated over the hole-injection layer 111 so that the thickness thereof was 20 nm.

[0488] Next, as the light-emitting layer 140(1), 2,8mDBtP2Bfpr, PCCP, and Ir(ppy)3 were co-evaporated over the hole-transport layer 112 so that the thicknesses thereof were 20 nm and the weight ratio (2,8mDBtP2Bfpr: PCCP: Ir(ppy)3) was 0.5:0.5:0.1. Next, as the light-emitting layer 140(2), the above materials were co-evaporated so that the thicknesses thereof were 20 nm and the weight ratio (2,8mDBtP2Bfpr: PCCP: Ir(ppy)3) was 0.8:0.2:0.1. Note that in the light-emitting layer 140, Ir(ppy)3 is a guest material that emits phosphorescent light.

[0489] As the electron transport layer 118, 2,8mDBtP2Bfpr and BPhen are sequentially deposited on the light-emitting layer 140 with thicknesses of 15nm and 10nm, respectively. Next, as the electron injection layer 119, LiF is deposited on the electron transport layer 118 with a thickness of 1nm.

[0490] As electrode 102, aluminum (Al) is formed on electron injection layer 119 with a thickness of 200 nm.

[0491] Next, in a nitrogen-atmospheric glove box, an organic EL sealant is used to fix the substrate 220 onto the substrate 200 on which the organic material is formed, thereby sealing the light-emitting element 2. Specifically, the sealant is applied around the organic material formed on the substrate 200, and the substrate 200 and the substrate 220 are bonded together at a pressure of 6 J / cm. 2 Irradiate with ultraviolet light at a wavelength of 365 nm and heat at 80°C for 1 hour. The light-emitting element 2 is obtained through the above process.

[0492] Characteristics of light-emitting elements

[0493] FIG. 20 The current efficiency-brightness characteristics of the manufactured light-emitting element 2 are shown. FIG. 22 The current density-voltage characteristics are shown. FIG. 21 The external quantum efficiency-luminance characteristics are shown. The characteristics of the light-emitting element 2 were tested at room temperature (in an atmosphere maintained at 23°C). FIG. 23 It shows 2.5 mA / cm 2 The current density was used to determine the electroluminescence spectrum when current flows through the light-emitting element 2. The measurements were performed at room temperature.

[0494] Table 4 shows the values ​​for 1000 cd / m³. 2 The characteristics of the nearby light-emitting element 2.

[0495] [Table 4]

[0496]

[0497] like FIG. 20 , FIG. 22 As shown in Table 4, light-emitting element 1 exhibits high current efficiency and external quantum efficiency. Furthermore, even on the high-brightness side, the efficiency reduction (attenuation) of light-emitting element 1 is minimal, which is an excellent result.

[0498] In addition, such as FIG. 21 As shown in Table 4, the driving voltage of the light-emitting element 2 is low, indicating good power efficiency.

[0499] like FIG. 23As shown, the light-emitting element 1 emits green light, in which the peak wavelength of the electroluminescent spectrum is 520 nm and the full width at half maximum is 72 nm. It is known from the obtained electroluminescent spectrum that the above light emission is derived from the guest material Ir(ppy)3.

[0500] <Reliability of light-emitting element>

[0501] Next, the light-emitting element 2 was subjected to a constant current driving test at 2 mA. FIG. 24 The results thereof are shown. From FIG. 24 It is known that the luminance half-life of the light-emitting element 2 exceeds 350 hours, and that the light-emitting element 2 has high reliability.

[0502] As described above, by using the compound of one embodiment of the present application for a light-emitting layer, a light-emitting element which exhibits high emission efficiency can be manufactured. In addition, a light-emitting element with low driving voltage and low power consumption can be manufactured. Furthermore, a light-emitting element with high reliability can be manufactured.

[0503] Symbol explanation

[0504] 100: EL layer, 101: electrode, 102: electrode, 106: light-emitting unit, 110: light-emitting unit, 111: hole injection layer, 112: hole transport layer, 113: electron transport layer, 114: electron injection layer, 115: charge generation layer, 116: hole injection layer, 117: hole transport layer, 118: electron transport layer, 119: electron injection layer, 120: light-emitting layer, 130: light-emitting layer, 140: light-emitting layer, 141: host material, 141_1: organic compound, 141_2: organic compound, 142: guest material, 150: light-emitting element, 170: light-emitting layer, 200: substrate, 220: substrate, 250: light-emitting element, 601: source side driver circuit, 602: pixel portion, 603: gate side driver circuit, 604: sealing substrate, 605: sealing agent, 607: space, 608: wiring, 610: element substrate, 611: switching TFT, 612: current control TFT, 613: electrode, 614: insulator, 616: EL layer, 617: electrode, 618: light-emitting element, 623: n-channel TFT, 624: p-channel TFT, 900: portable information terminal, 901: housing, 902: housing, 903: display portion, 905: hinge portion, 910: portable information terminal, 911: housing, 912: display portion, 913: operation button, 914: external connection port, 915: speaker, 916: microphone, 917: camera, 920: camera, 921: housing, 922: display portion, 923: operation button, 924: shutter button, 926: lens, 1001: substrate, 1002: base insulating film, 1003: gate insulating film, 1006: gate electrode, 1007: gate electrode, 1008: gate electrode, 1020: interlayer insulating film, 1021: interlayer insulating film, 1022: electrode, 1024B: electrode, 1024G: electrode, 1024R: electrode, 1024W: electrode, 1025B: lower electrode, 1025G: lower electrode, 1025R: lower electrode, 1025W: lower electrode, 1026: partition wall, 1028: EL layer, 1029: electrode, 1031: sealing substrate, 1032: sealing agent, 1033: base material, 1034B: coloring layer, 1034G: coloring layer, 1034R: coloring layer, 1035: black layer, 1036: protective layer, 1037: interlayer insulating film, 1040: pixel portion, 1041: driver circuit portion, 1042: peripheral portion, 3500: multifunctional terminal, 3502: housing, 3504: display portion, 3506: camera, 3508: illumination, 3600: lamp, 3602: housing, 3608: illumination, 3610: speaker, 8501: lighting device, 8502: lighting device, 8503: lighting device, 8504: lighting device, 9000: housing, 9001: display portion,9003: speaker, 9005: operation key, 9006: connection terminal, 9007: sensor, 9008: microphone, 9055: hinge, 9200: portable information terminal, 9201: portable information terminal, 9202: portable information terminal.

[0505] This application is based on Japanese Patent Application No. 2016-254916 filed on December 28, 2016 with the Japan Patent Office, the entire contents of which are hereby incorporated by reference.

Claims

1. A light-emitting element comprising an EL layer between a pair of electrodes, in, The EL layer comprises a substance containing a benzofuran-pyrazine skeleton or a substance containing a benzothiophene-pyrazine skeleton. The benzene ring in the benzofuranopyrazine skeleton or the benzene ring in the benzothiophenopyrazine skeleton contains a first substituent having a total carbon number of 6 to 100. The first substituent comprises a fused aromatic heterocycle bonded to the benzene ring by a substituted or unsubstituted arylene group. The pyrazine ring in the benzofuranopyrazine skeleton or the pyrazine ring in the benzothiophene pyrazine skeleton contains a second substituent having a total carbon number of 6 to 100. Furthermore, the second substituent comprises a π-electron-rich aromatic heterocycle bonded to the pyrazine ring by a substituted or unsubstituted arylene group, or a triarylamine structure bonded to the pyrazine ring by a substituted or unsubstituted arylene group.

2. The light-emitting element according to claim 1, The first substituent and the second substituent each independently comprise an aromatic ring having 10 to 30 carbon atoms or an aromatic heterocyclic ring having 10 to 30 carbon atoms.

3. The light-emitting element according to claim 1, The first substituent and the second substituent each independently comprise at least one of the following structures: a substituted or unsubstituted benzene ring, a substituted or unsubstituted naphthalene ring, a substituted or unsubstituted phenanthrene ring, a substituted or unsubstituted triphenylene ring, a fused aromatic heterocycle having 12 to 30 carbon atoms, and a substituted or unsubstituted triarylamine structure. Furthermore, the fused aromatic heterocycle comprises any one of a dibenzofuran ring, a dibenzothiophene ring, and a carbazole ring.

4. The light-emitting element according to claim 1, The second substituent comprises a hole-transporting backbone.

5. The light-emitting element according to claim 4, The hole-transporting framework is a fused aromatic heterocycle containing any one of a carbazole ring, a dibenzofuran ring, and a dibenzothiophene ring.

6. The light-emitting element according to claim 1, The EL layer includes a light-emitting layer. Furthermore, the light-emitting layer includes a substance containing the benzofuran-pyrazine skeleton or the benzothiophene-pyrazine skeleton and a substance capable of converting triple excitation energy into light emission.

7. The light-emitting element according to claim 1, The EL layer includes a light-emitting layer. Furthermore, the luminescent layer includes a substance containing the benzofuran-pyrazine skeleton or the benzothiophene-pyrazine skeleton and a phosphorescent compound.

8. An organic compound represented by the general formula (G0): ， in: X represents oxygen or sulfur; A 1 and A 2 Each can independently represent a substituent having 6 to 100 carbon atoms; A 1 A fused aromatic heterocycle comprising a benzene ring in the general formula (G0) bonded by a substituted or unsubstituted aryl group having a carbon atom number of 6 to 25; A 2 The structure comprises a π-electron-rich aromatic heterocycle having a 6 to 25 arylene groups of substituted or unsubstituted carbon atoms bonded to the pyrazine ring in the general formula (G0), or a triarylamine structure having a 6 to 25 arylene groups of substituted or unsubstituted carbon atoms bonded to the pyrazine ring in the general formula (G0). Furthermore, R 1 To R 4 Each of the following can be independently represented as hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms (substituted or unsubstituted), or an aryl group having 6 to 25 carbon atoms (substituted or unsubstituted).

9. The organic compound according to claim 8, Where A 1 and A 2 Each of them independently contains an aromatic ring or a heterocyclic aromatic ring with 10 to 30 carbon atoms.

10. The organic compound according to claim 8, Where A 1 and A 2 Each of the following independently comprises at least one of the following structures: a substituted or unsubstituted benzene ring, a substituted or unsubstituted naphthalene ring, a substituted or unsubstituted phenanthrene ring, a substituted or unsubstituted triphenylene ring, a fused aromatic heterocycle having 12 to 30 carbon atoms, and a substituted or unsubstituted triphenylamine structure. Furthermore, the fused aromatic heterocycle comprises a dibenzofuran ring, a dibenzothiophene ring, or a carbazole ring.

11. The organic compound according to claim 8, Where A 2 It comprises a fused aromatic heterocycle containing any one of a carbazole ring, a dibenzofuran ring, and a dibenzothiophene ring.

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