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: A light-emitting element having high external quantum efficiency is provided. A light-emitting element having low drive voltage is provided. Provided is a light-emitting element which includes a light-emitting layer containing a phosphorescent compound, a first organic compound, and a second organic compound between a pair of electrodes. A combination of the first organic compound and the second organic compound forms an exciplex (excited complex). An emission spectrum of the exciplex overlaps with an absorption band located on the longest wavelength side of an absorption spectrum of the phosphorescent compound. A peak wavelength of the emission spectrum of the exciplex is longer than or equal to a peak wavelength of the absorption band located on the longest wavelength side of the absorption spectrum of the phosphorescent compound.

Abstract: A light-emitting element includes a light-emitting layer including a guest, an n-type host and a p-type host between a pair of electrodes, where the difference between the energy difference between a triplet excited state and a ground state of the n-type host (or p-type host) and the energy difference between a triplet excited state and a ground state of the guest is 0.15 eV or more. Alternatively, in such a light-emitting element, the LUMO level of the n-type host is higher than the LUMO level of the guest by 0.1 eV or more, or the HOMO level of the p-type host is lower than the HOMO level of the guest by 0.1 eV or more.

Abstract: A light-emitting element with high emission efficiency and high reliability is provided. The light-emitting element includes a light-emitting layer containing a first organic compound, a second organic compound, and a guest material. The first organic compound has a nitrogen-containing six-membered heteroaromatic skeleton. In the light-emitting layer, the weight ratio of an organic compound having a nitrogen-containing five-membered heterocyclic skeleton with an NH group, a secondary amine skeleton with an NH group, or a primary amine skeleton with an NH group to the first organic compound is less than or equal to 0.03, or alternatively, the weight ratio of the organic compound having a nitrogen-containing five-membered heterocyclic skeleton with an NH group, a secondary amine skeleton with an NH group, or a primary amine skeleton with an NH group to the second organic compound is less than or equal to 0.01.

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: Objects of the present invention are to provide: a light-emitting element having a long lifetime and good emission efficiency and drive voltage. One embodiment of the invention is a light-emitting element including, between an anode and a cathode, at least a stack structure in which a first layer, a second layer, and a light-emitting layer are provided in order from the anode side. The first layer includes a first organic compound and an electron-accepting compound. The second layer includes a second organic compound having a HOMO level differing from the HOMO level of the first organic compound by from ?0.2 eV to +0.2 eV. The light-emitting layer includes a third organic compound having a HOMO level differing from the HOMO level of the second organic compound by from ?0.2 eV to +0.2 eV and a light-emitting substance having a hole-trapping property with respect to the third organic compound.

Abstract: A light-emitting element with high emission efficiency and high reliability is provided. The light-emitting element includes a light-emitting layer containing a first organic compound, a second organic compound, and a guest material. The first organic compound has a nitrogen-containing six-membered heteroaromatic skeleton. In the light-emitting layer, the weight ratio of an organic compound having a nitrogen-containing five-membered heterocyclic skeleton with an NH group, a secondary amine skeleton with an NH group, or a primary amine skeleton with an NH group to the first organic compound is less than or equal to 0.03, or alternatively, the weight ratio of the organic compound having a nitrogen-containing five-membered heterocyclic skeleton with an NH group, a secondary amine skeleton with an NH group, or a primary amine skeleton with an NH group to the second organic compound is less than or equal to 0.01.

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: 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 is provided which includes a light-emitting layer containing a phosphorescent compound, a first organic compound, and a second organic compound between a pair of electrodes, in which a combination of the first organic compound and the second organic compound forms an exciplex (excited complex). The light-emitting element transfers energy by utilizing an overlap between the emission spectrum of the exciplex and the absorption spectrum of the phosphorescent compound and thus has high energy transfer efficiency. Therefore, a light-emitting element having high external quantum efficiency can be obtained.

Abstract: To provide a light-emitting element having high luminous efficiency and to provide a light-emitting device and an electronic device which consumes low power and is driven at low voltage, a carbazole derivative represented by the general formula (1) is provided. In the formula, ?1, ?2, ?3, and ?1 each represent an azylene stoup having less than or equal to 13 carbon atoms; Ar1 and Ar2 each represent an aryl group having less than or equal to 13 carbon atoms; R1 represents any of a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted phenyl group, and a substituted or unsubstituted biphenyl group; and R2 represents any of an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted phenyl group, and a substituted or unsubstituted biphenyl group. In addition, l, m, and n are each independently 0 or 1.

Abstract: A light-emitting element with high emission efficiency and high reliability is provided. The light-emitting element includes a light-emitting layer containing a first organic compound, a second organic compound, and a guest material. The first organic compound has a nitrogen-containing six-membered heteroaromatic skeleton. In the light-emitting layer, the weight ratio of an organic compound having a nitrogen-containing five-membered heterocyclic skeleton with an NH group, a secondary amine skeleton with an NH group, or a primary amine skeleton with an NH group to the first organic compound is less than or equal to 0.03, or alternatively, the weight ratio of the organic compound having a nitrogen-containing five-membered heterocyclic skeleton with an NH group, a secondary amine skeleton with an NH group, or a primary amine skeleton with an NH group to the second organic compound is less than or equal to 0.01.

Abstract: To provide a light-emitting element with high emission efficiency. In a light-emitting element including an organic compound between a pair of electrodes, the molecular weight X of the organic compound is 450 or more and 1500 or less, and the absorption edge of the organic compound is at 380 nm or more. By liquid chromatography mass spectrometry in a positive mode in which an argon gas is made to collide with the organic compound subjected to separation using a liquid chromatograph at any energy higher than or equal to 1 eV and lower than or equal to 30 eV, a product ion is detected at least around m/z=(X?240).

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: A light-emitting element includes a light-emitting layer including a guest, an n-type host and a p-type host between a pair of electrodes, where the difference between the energy difference between a triplet excited state and a ground state of the n-type host (or p-type host) and the energy difference between a triplet excited state and a ground state of the guest is 0.15 eV or more. Alternatively, in such a light-emitting element, the LUMO level of the n-type host is higher than the LUMO level of the guest by 0.1 eV or more, or the HOMO level of the p-type host is lower than the HOMO level of the guest by 0.1 eV or more.

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: 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 is provided which includes a light-emitting layer containing a phosphorescent compound, a first organic compound, and a second organic compound between a pair of electrodes, in which a combination of the first organic compound and the second organic compound forms an exciplex (excited complex). The light-emitting element transfers energy by utilizing an overlap between the emission spectrum of the exciplex and the absorption spectrum of the phosphorescent compound and thus has high energy transfer efficiency. Therefore, a light-emitting element having high external quantum efficiency can be obtained.

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 is provided which includes a light-emitting layer containing a phosphorescent compound, a first organic compound, and a second organic compound between a pair of electrodes, in which a combination of the first organic compound and the second organic compound forms an exciplex (excited complex). The light-emitting element transfers energy by utilizing an overlap between the emission spectrum of the exciplex and the absorption spectrum of the phosphorescent compound and thus has high energy transfer efficiency. Therefore, a light-emitting element having high external quantum efficiency can be obtained.

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 is provided which includes a light-emitting layer containing a phosphorescent compound, a first organic compound, and a second organic compound between a pair of electrodes, in which a combination of the first organic compound and the second organic compound forms an exciplex (excited complex). The light-emitting element transfers energy by utilizing an overlap between the emission spectrum of the exciplex and the absorption spectrum of the phosphorescent compound and thus has high energy transfer efficiency. Therefore, a light-emitting element having high external quantum efficiency can be obtained.

Abstract: To provide a light-emitting element having high luminous efficiency and to provide a light-emitting device and an electronic device which consumes low power and is driven at low voltage, a carbazole derivative represented by the general formula (1) is provided. In the formula, ?1, ?2, ?3, and ?4 each represent an arylene group having less than or equal to 13 carbon atoms; Ar1 and Ar2 each represent an aryl group having less than or equal to 13 carbon atoms; R1 represents any of a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted phenyl group, and a substituted or unsubstituted biphenyl group; and R2 represents any of an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted phenyl group, and a substituted or unsubstituted biphenyl group. In addition, l, m, and n are each independently 0 or 1.

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.