Abstract: A light-emitting element which has low driving voltage and high emission efficiency is provided. The light-emitting element includes, between a pair of electrodes, a hole-transport layer and a light-emitting layer over the hole-transport layer. The light-emitting layer contains a first organic compound having an electron-transport property, a second organic compound having a hole-transport property, and a light-emitting third organic compound converting triplet excitation energy into light emission. A combination of the first organic compound and the second organic compound forms an exciplex. The hole-transport layer contains at least a fourth organic compound whose HOMO level is lower than or equal to that of the second organic compound and a fifth organic compound whose HOMO level is higher than that of the second organic compound.

Abstract: Provided is a novel heterocyclic compound which can be used in a light-emitting layer of a light-emitting element as a host material in which a light-emitting material is dispersed, i.e., a heterocyclic compound represented by a general formula (G1). Any one of R1 to R10 represents a substituent represented by a general formula (G1-1); another one of R1 to R10 represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, or a substituent represented by a general formula (G1-2); and the others separately represent hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted phenyl group, or a substituted or unsubstituted biphenyl group.

Abstract: A light-emitting element which has low driving voltage and high emission efficiency is provided. The light-emitting element includes, between a pair of electrodes, a hole-transport layer and a light-emitting layer over the hole-transport layer. The light-emitting layer contains a first organic compound having an electron-transport property, a second organic compound having a hole-transport property, and a light-emitting third organic compound converting triplet excitation energy into light emission. A combination of the first organic compound and the second organic compound forms an exciplex. The hole-transport layer is formed using two or more kinds of organic compounds and contains at least the second organic compound.

Abstract: Provided is a novel heterocyclic compound which can be used for a light-emitting element, as a host material of a light-emitting layer in which a light-emitting substance is dispersed. A heterocyclic compound represented by a general formula (G1) is provided. In the formula, A represents any of a substituted or unsubstituted dibenzothiophenyl group, a substituted or unsubstituted dibenzofuranyl group, and a substituted or unsubstituted carbazolyl group, R11 to R19 separately represent any of hydrogen, an alkyl group having 1 to 4 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, and Ar represents a substituted or unsubstituted arylene 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: An object is to provide a light-emitting element having high light-emission efficiency by provision of a novel fluorene derivative as represented by General. Formula (G1) below. In the formula, R1 to R8 independently represent any of a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted phenyl group, or a substituted or unsubstituted biphenyl group. Further, ?1 to ?4 independently represent any of a substituted or unsubstituted arylene group having 6 to 12 carbon atoms. Furthermore, Ar1 and Ar2 independently represent any of an aryl group having 6 to 13 carbon atoms in a ring and Ar3 represents an alkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms. J, k, m, and n each independently represent 0 or 1.

Abstract: To provide a novel carbazole compound that has an excellent carrier-transport property and can be used for a transport layer or as a host material in a light-emitting element. Further, to provide an organic semiconductor material and a material for a light-emitting element using the carbazole compound. A carbazole compound in which the 4-position of a dibenzothiophene skeleton or a dibenzofuran skeleton is substituted with the 2- or 3-position of a carbazole skeleton directly or via an arylene group can be synthesized. The carbazole compound is found to have a suitable carrier-transport property, a good film quality, and be used suitably as a material of a light-emitting element and an organic semicondcutor material. Note that nitrogen of the carbazole skeleton is substituted with any of a phenyl group, a biphenyl group, and a naphthyl group.

Abstract: Provided is a novel heterocyclic compound which can be used in a light-emitting layer of a light-emitting element as a host material in which a light-emitting substance is dispersed. A heterocyclic compound represented by a general formula (G1) is provided. Any one of R1 to R10 represents a substituent represented by a general formula (G1-1), another one of R1 to R10 represents a substituent represented by a general formula (G1-2), and the others separately represent hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted phenyl group, or a substituted or unsubstituted biphenyl group. Further, ?1 and ?2 separately represent a substituted or unsubstituted phenylene group or a substituted or unsubstituted biphenyldiyl group, and A1 and A2 separately represent a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted dibenzothiophenyl group, or a substituted or unsubstituted dibenzofuranyl group.

Abstract: A new light-emitting device utilizing phosphorescence is provided. Further, an electronic device and a lighting device which utilize phosphorescence are provided. One embodiment of the present invention is a light-emitting device including a phosphorescent organometallic iridium complex comprising iridium and either pyrimidine having an aryl group at the 4-position or 1,3,5-triazine having an aryl group at the 2-position. One of nitrogen in the pyrimidine or 1,3,5-triazine is coordinated to the iridium. Also, each of the pyrimidine and 1,3,5-triazine has a substituent such as an alkyl group or an aryl group. Further the ortho position of the aryl group which is bonded to the 4-position of the pyrimidine or the 2-position of the 1,3,5-triazine is bonded to the iridium.

Abstract: To provide a light-emitting element with high emission efficiency or long lifetime, in which the use amount of a phosphorescent compound is small. To provide a light-emitting element including a light-emitting layer between a pair of electrodes, wherein the light-emitting layer includes a phosphorescent compound, a first organic compound, and a second organic compound, and the combination of the first organic compound and the second organic compound forms an exciplex. The light-emitting element transfers energy by utilizing the overlap between the emission spectrum of the exciplex and the absorption spectrum of the phosphorescent compound and thus has high energy transfer efficiency, even when the concentration of the phosphorescent compound is low.

Abstract: A substance having a hole-transport property and a wide band gap is provided. A fluorene compound represented by a general formula (G1) is provided. In the general formula (G1), ?1 and ?2 separately represent a substituted or unsubstituted arylene group having 6 to 13 carbon atoms; Ar1 represents a substituted or unsubstituted aryl group having 6 to 18 carbon atoms, a substituted or unsubstituted 4-dibenzothiophenyl group, or a substituted or unsubstituted 4-dibenzofuranyl group; n and k separately represent 0 or 1; Q1 represents sulfur or oxygen; and R1 to R15 separately represent hydrogen, an alkyl group having 1 to 12 carbon atoms, or an aryl group having 6 to 14 carbon atoms.

Abstract: A novel substance with which an increase in life and emission efficiency of a light-emitting element can be achieved is provided. A carbazole compound having a structure represented by General Formula (G1) is provided. Note that a substituent which makes the HOMO level and the LUMO level of a compound in which a bond of the substituent is substituted with hydrogen deep and shallow, respectively is used as each of substituents in General Formula (G1) (R1, R2, Ar3, and ?3). Further, a substituent which makes the band gap (Bg) and the T1 level of a compound in which a bond of the substituent is substituted with hydrogen wide and high is used as each of the substituents in General Formula (G1) (R1, R2, Ar3, and ?3).

Abstract: To provide a novel organometallic complex, and light emitting elements, light emitting devices, and electronic devices which include the organometallic complex. In addition, to provide a composition in which the organometallic complex is dissolved and to provide a method for manufacturing light emitting elements using the composition. An organometallic complex has high solubility in a solvent. In the organometallic complex, the ligand including a pyrazine skeleton is bound to an atom belonging to Group 9 (Co, Rh, or Ir) or an atom belonging to Group 10 (Ni, Pd, or Pt). In addition, the light emission efficiency is high. Therefore, the organometallic complex is preferably used for manufacturing a light emitting element.

Abstract: A carbazole compound represented by General Formula (G1) is provided. In the formula, ? represents a phenylene group, Ar1 represents an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, or a substituted or unsubstituted phenanthryl group, Ar2 represents hydrogen, a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, or a substituted or unsubstituted phenanthryl group, Ar3 represents a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, or a substituted or unsubstituted phenanthryl group, and R1 represents hydrogen, an alkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted phenyl group. Further, n is 0 or 1.

Abstract: A light-emitting element which has low driving voltage and high emission efficiency is provided. The light-emitting element includes, between a pair of electrodes, a hole-transport layer and a light-emitting layer over the hole-transport layer. The light-emitting layer contains a first organic compound having an electron-transport property, a second organic compound having a hole-transport property, and a light-emitting third organic compound converting triplet excitation energy into light emission. A combination of the first organic compound and the second organic compound forms an exciplex. The hole-transport layer contains at least a fourth organic compound whose HOMO level is lower than or equal to that of the second organic compound and a fifth organic compound whose HOMO level is higher than that of the second organic compound.

Abstract: Provided is a novel heterocyclic compound which can be used for a light-emitting element, as a host material of a light-emitting layer in which a light-emitting substance is dispersed. A heterocyclic compound represented by a general formula (G1) is provided. In the formula, A represents any of a substituted or unsubstituted dibenzothiophenyl group, a substituted or unsubstituted dibenzofuranyl group, and a substituted or unsubstituted carbazolyl group, R11 to R19 separately represent any of hydrogen, an alkyl group having 1 to 4 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 14 carbon atoms, and Ar represents a substituted or unsubstituted arylene group having 6 to 13 carbon atoms.

Abstract: Provided is a novel heterocyclic compound which can be used for a light-emitting element, as a host material of a light-emitting layer in which a light-emitting substance is dispersed. A heterocyclic compound represented by a general formula (G1) is provided. In the formula, A represents any of a substituted or unsubstituted dibenzothiophenyl group, a substituted or unsubstituted dibenzofuranyl group, and a substituted or unsubstituted carbazolyl group, R11 to R19 separately represent any of hydrogen, an alkyl group having 1 to 4 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, and Ar represents a substituted or unsubstituted arylene group having 6 to 13 carbon atoms.

Abstract: One embodiment of the present invention is a fluorene compound. Specifically, one embodiment of the present invention is a fluorene compound in which two 9-phenylfluoren-9-yl groups are each bonded to any of a pyridine skeleton and a pyrimidine skeleton through an arylene group, and in which the arylene group is any of one to three phenylene groups.

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: An object is to provide a light-emitting element having high light-emission efficiency by provision of a novel fluorene derivative as represented by General Formula (G1) below. In the formula, R1 to R8 independently represent any of a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted phenyl group, or a substituted or unsubstituted biphenyl group. Further, ?1 to ?4 independently represent any of a substituted or unsubstituted arylene group having 6 to 12 carbon atoms. Furthermore, Ar1 and Ar2 independently represent any of an aryl group having 6 to 13 carbon atoms in a ring and Ar3 represents an alkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms. J, k, m, and n each independently represent 0 or 1.