Abstract: A light-emitting element with high heat resistance and high emission efficiency is provided. A novel heterocyclic compound that can be used in such a light-emitting element is provided. One embodiment of the present invention is a light-emitting element which includes, between a pair of electrodes, a layer containing a first organic compound, a second organic compound, and a light-emitting substance; the first organic compound includes one pyrimidine ring and one ring with a hole-transport skeleton; the second organic compound is an aromatic amine; and the light-emitting substance converts triplet excitation energy into light. A combination of the first organic compound, which includes the one pyrimidine ring and the one ring with the hole-transport skeleton, and the second organic compound, which is the aromatic amine, forms an exciplex.

Abstract: A light-emitting element having a long lifetime is provided. A light-emitting element exhibiting high emission efficiency in a high luminance region is provided. A light-emitting element includes a light-emitting layer between a pair of electrodes. The light-emitting layer contains a first organic compound, a second organic compound, and a phosphorescent compound. The first organic compound is represented by a general formula (G0). The molecular weight of the first organic compound is greater than or equal to 500 and less than or equal to 2000. The second organic compound is a compound having an electron-transport property. In the general formula (G0), Ar1 and Ar2 each independently represent a fluorenyl group, a spirofluorenyl group, or a biphenyl group, and Ar3 represents a substituent including a carbazole skeleton.

Abstract: An organic compound having a low HOMO level and a high hole-transport property is provided. The organic compound is represented by Formula (G1), where Ar1 represents a substituted or unsubstituted fluorenyl group, Ar2 represents a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, and A1 represents any one of a substituted or unsubstituted dibenzofuranyl group and a substituted or unsubstituted dibenzothiophenyl group. The low HOMO level and the high hole-transport property of the organic compound allow the formation of an exciplex with another organic compound, which leads to a highly efficient light-emitting element in the presence of a phosphorescent compound due to the effective overlapping between the emission of the exciplex and the longest absorption band of the phosphorescent compound.

Abstract: To provide a novel heterocyclic compound that can be used as a host material in which a light-emitting substance of a light-emitting layer is dispersed. A heterocyclic compound comprising a dibenzo[f,h]quinoxaline ring and two hole-transport skeletons, where the dibenzo[f,h]quinoxaline ring and the two hole-transport skeletons are bonded to an aromatic hydrocarbon group. A heterocyclic compound represented by the following general formula (G1) is provided. Note that in the formula, A1 and A2 each independently represent any of a substituted or unsubstituted carbazole skeleton, a substituted or unsubstituted dibenzofuran skeleton, and a substituted or unsubstituted dibenzothiophen skeleton; B represents a substituted or unsubstituted dibenzo[f,h]quinoxaline skeleton; and Ar represents an arene skeleton having 6 to 13 carbon atoms. A light-emitting element including the heterocyclic compound is provided.

Abstract: A light-emitting element having high external quantum efficiency is provided. A light-emitting element having a long lifetime is provided. A light-emitting layer is provided between a pair of electrodes. The light-emitting layer is a stack of a first light-emitting layer, which contains at least a first phosphorescent compound, a first organic compound having an electron-transport property, and a second organic compound having a hole-transport property and is provided on the anode side, and a second light-emitting layer, which contains at least a second phosphorescent compound and the first organic compound having an electron-transport property. A combination of the first organic compound and the second organic compound forms an exciplex.

Abstract: A light-emitting element having high external quantum efficiency is provided. A light-emitting element having a long lifetime is provided. A light-emitting element includes a light-emitting layer between a pair of electrodes. The light-emitting layer contains at least a phosphorescent compound, a first organic compound (host material) having an electron-transport property, and a second organic compound (assist material) having a hole-transport property. The light-emitting layer has a stacked-layer structure including a first light-emitting layer and a second light-emitting layer, and the first light-emitting layer contains a higher proportion of the second organic compound than the second light-emitting layer. In the light-emitting layer (the first light-emitting layer and the second light-emitting layer), a combination of the first organic compound and the second organic compound forms an exciplex.

Abstract: A novel substance capable of emitting phosphorescence is provided. An organometallic complex represented by General Fomulae (G3) or (G5). In the formulae, M represents iridium, platinum, palladium, or rhodium, R1 represents a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 10 carbon atoms, and R2 to R7 separately represent hydrogen or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms.

Abstract: A composite material including an organic compound and an inorganic compound, which has a high carrier-transport property; a composite material having an excellent property of carrier injection to an organic compound; a composite material in which light absorption due to charge transfer interaction is unlikely to occur; and a composite material having a high visible-light-transmitting property are provided. A composite material which includes an organic compound and an inorganic compound exhibiting an electron-accepting property with respect to the organic compound, in which the rings of the organic compound are all benzene rings and the number of the benzene rings of the organic compound is greater than or equal to 4 and less than or equal to 25, is provided.

Abstract: A light-emitting element having a long lifetime is provided. A light-emitting element exhibiting high emission efficiency in a high luminance region is provided. A light-emitting element includes a light-emitting layer between a pair of electrodes. The light-emitting layer contains a first organic compound, a second organic compound, and a phosphorescent compound. The first organic compound is represented by a general formula (G0). The molecular weight of the first organic compound is greater than or equal to 500 and less than or equal to 2000. The second organic compound is a compound having an electron-transport property. In the general formula (G0), Ar1 and Ar2 each independently represent a fluorenyl group, a spirofluorenyl group, or a biphenyl group, and Ar3 represents a substituent including a carbazole skeleton.

Abstract: A light-emitting element with high heat resistance and high emission efficiency is provided. A novel heterocyclic compound that can be used in such a light-emitting element is provided. One embodiment of the present invention is a light-emitting element which includes, between a pair of electrodes, a layer containing a first organic compound, a second organic compound, and a light-emitting substance; the first organic compound includes one pyrimidine ring and one ring with a hole-transport skeleton; the second organic compound is an aromatic amine; and the light-emitting substance converts triplet excitation energy into light. A combination of the first organic compound, which includes the one pyrimidine ring and the one ring with the hole-transport skeleton, and the second organic compound, which is the aromatic amine, forms an exciplex.

Abstract: To provide a novel heterocyclic compound that can be used as a host material in which a light-emitting substance of a light-emitting layer is dispersed. A heterocyclic compound comprising a dibenzo[f,h]quinoxaline ring and two hole-transport skeletons, where the dibenzo[f,h]quinoxaline ring and the two hole-transport skeletons are bonded to an aromatic hydrocarbon group. A heterocyclic compound represented by the following general formula (G1) is provided. Note that in the formula, A1 and A2 each independently represent any of a substituted or unsubstituted carbazole skeleton, a substituted or unsubstituted dibenzofuran skeleton, and a substituted or unsubstituted dibenzothiophen skeleton; B represents a substituted or unsubstituted dibenzo[f,h]quinoxaline skeleton; and Ar represents an arene skeleton having 6 to 13 carbon atoms. A light-emitting element including the heterocyclic compound is provided.

Abstract: A light-emitting element having high external quantum efficiency is provided. A light-emitting element having a long lifetime is provided. A light-emitting layer is provided between a pair of electrodes. The light-emitting layer is a stack of a first light-emitting layer, which contains at least a first phosphorescent compound, a first organic compound having an electron-transport property, and a second organic compound having a hole-transport property and is provided on the anode side, and a second light-emitting layer, which contains at least a second phosphorescent compound and the first organic compound having an electron-transport property. A combination of the first organic compound and the second organic compound forms an exciplex.

Abstract: Provided is a light-emitting element in which an adverse effect by halides in an EL layer is suppressed and which can be provided with low cost. The light-emitting element including at least two layers between an anode and a light-emitting layer. One of the two layers which is closer to the anode has higher concentration of halides and halogen elements than the other layer closer to the light-emitting layer.

Abstract: To provide an organometallic complex with high emission efficiency and high heat resistance, which emits yellow green light. The organometallic complex includes a metal and a ligand which is a benzo[h]quinazoline skeleton including a condensed ring bonded to benzo[h]quinazoline through a carbon-carbon bond between the 5-position and the 6-position. The organometallic complex has a structure represented by General Formula (G1). In General Formula (G1), M represents a metal belonging to Group 9 or 10; each of R1 to R4 independently represents hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 10 carbon atoms; and R5 represents hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted phenyl group. A ring X represents a substituted or unsubstituted six-membered aromatic ring formed with carbon or both carbon and nitrogen.

Abstract: To provide a light-emitting element which uses a fluorescent material as a light-emitting substance and has higher luminous efficiency. To provide a light-emitting element which includes a mixture of a thermally activated delayed fluorescent substance and a fluorescent material. By making the emission spectrum of the thermally activated delayed fluorescent substance overlap with an absorption band on the longest wavelength side in absorption by the fluorescent material in an S1 level of the fluorescent material, energy at an S1 level of the thermally activated delayed fluorescent substance can be transferred to the S1 of the fluorescent material. Alternatively, it is also possible that the Si of the thermally activated delayed fluorescent substance is generated from part of the energy of a T1 level of the thermally activated delayed fluorescent substance, and is transferred to the S1 of the fluorescent material.

Abstract: To provide a novel heterocyclic compound capable of being used as a host material in which a light-emitting substance is dispersed. To provide a light-emitting element having a long lifetime. A heterocyclic compound in which a dibenzo[f,h]quinoxalinyl group and a benzo[b]naphtho[1,2-d]furanyl group are bonded through an arylene group having 6 to 13 carbon atoms. The dibenzo[f,h]quinoxalinyl group, the benzo[b]naphtho[1,2-d]furanyl group, and the arylene group separately are unsubstituted or have, as a substituent, an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 13 carbon atoms.

Abstract: A light-emitting element having high external quantum efficiency is provided. A light-emitting element having a long lifetime is provided. A light-emitting element includes a light-emitting layer between a pair of electrodes. The light-emitting layer contains at least a phosphorescent compound, a first organic compound (host material) having an electron-transport property, and a second organic compound (assist material) having a hole-transport property. The light-emitting layer has a stacked-layer structure including a first light-emitting layer and a second light-emitting layer, and the first light-emitting layer contains a higher proportion of the second organic compound than the second light-emitting layer. In the light-emitting layer (the first light-emitting layer and the second light-emitting layer), a combination of the first organic compound and the second organic compound forms an exciplex.

Abstract: A novel organic compound is provided. In addition, a novel organic compound with high heat resistance is provided. In the organic compound, a dibenzoquinoxaline skeleton and a 4,4-bidibenzofuran skeleton or a 4,4?-bidibezothiophene skeleton are connected to each other through an arylene group.

Abstract: An organometallic iridium complex having high emission efficiency and high heat resistance and emitting yellow light is provided as a novel substance. The organometallic iridium complex includes iridium and a ligand and includes a structure represented by General Formula (G1). The ligand includes a 5H-indeno[1,2-d]pyrimidine skeleton and an aryl group bonded to the 4-position of the 5H-indeno[1,2-d]pyrimidine skeleton. The 3-position of the 5H-indeno[1,2-d]pyrimidine skeleton and the aryl group are bonded to the iridium. In the formula, Ar represents a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, and each of R1 to R7 independently represents hydrogen or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms.

Abstract: Provided is a light-emitting element with a small degree of luminance degradation with accumulation of driving time (a long-lifetime light-emitting element). Provided is a light-emitting element in which a light-emitting layer with an electron-transport property is formed with a plurality of layers containing different host materials. Further, the LUMO level of a host material on an anode side is higher than the LUMO level of a host material on a cathode side. With such a structure, it is possible to provide a long-lifetime light-emitting element with little degradation in luminance with accumulation of driving time.