Abstract: A novel light-emitting device is provided. A light-emitting device with high emission efficiency is provided. A light-emitting device with a long lifetime is provided. A light-emitting device with low driving voltage is provided. The light-emitting device includes an anode, a cathode, and an EL layer between the anode and the cathode. The EL layer includes a hole-injection layer, a light-emitting layer, and an electron-transport layer. The hole-injection layer is positioned between the anode and the light-emitting layer. The electron-transport layer is positioned between the light-emitting layer and the cathode. The hole-injection layer contains a first substance and a second substance. The first substance is an organic compound which has a hole-transport property and a HOMO level higher than or equal to ?5.7 eV and lower than or equal to ?5.4 eV. The second substance exhibits an electron-accepting property with respect to the first substance.

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 (GO). 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 (GO), 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 multicolor light-emitting element using fluorescence and phosphorescence, which has a small number of manufacturing steps owing to a relatively small number of layers to be formed and is advantageous for practical application can be provided. In addition, a multicolor light-emitting element using fluorescence and phosphorescence, which has favorable emission efficiency is provided. A light-emitting element which includes a light-emitting layer having a stacked-layer structure of a first light-emitting layer exhibiting light emission from a first exciplex and a second light-emitting layer exhibiting phosphorescence 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: 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 S1 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: A light-emitting element includes an EL layer between a pair of electrodes. The EL layer contains a first compound and a second compound. The first compound is a phosphorescent iridium metal complex having a LUMO level of greater than or equal to ?3.5 eV and less than or equal to ?2.5 eV, and the second compound is an organic compound having a pyrimidine skeleton. The light-emitting element includes an EL layer between a pair of electrodes. The EL layer contains a first compound and a second compound. The first compound is a phosphorescent iridium metal complex having a diazine skeleton, and the second compound is an organic compound having a pyrimidine skeleton.

Abstract: A light-emitting element includes an EL layer between a pair of electrodes. The EL layer contains a first compound and a second compound. The first compound is a phosphorescent iridium metal complex having a LUMO level of greater than or equal to ?3.5 eV and less than or equal to ?2.5 eV, and the second compound is an organic compound having a pyrimidine skeleton. The light-emitting element includes an EL layer between a pair of electrodes. The EL layer contains a first compound and a second compound. The first compound is a phosphorescent iridium metal complex having a diazine skeleton, and the second compound is an organic compound having a pyrimidine skeleton.

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: 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 S1 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: A light-emitting element having high emission efficiency is provided. A light-emitting element having a low driving voltage is provided. A novel compound which can be used for a transport layer or as a host material or a light-emitting material of a light-emitting element is provided. A novel compound with a benzofuropyrimidine skeleton is provided. Also provided is a light-emitting element which includes the compound with the benzofuropyrimidine skeleton between a pair of electrodes.

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: An organic semiconductor element with low driving voltage is provided. The organic semiconductor element includes a first electrode, a second electrode, and a hole-transport layer and an active layer between the first electrode and the second electrode. The hole-transport layer includes a first hole-transport layer and a second hole-transport layer. The first hole-transport layer is closer to the substrate than the second hole-transport layer is. The first hole-transport layer and the second hole-transport layer are in contact with each other. A value obtained by subtracting GSP_slope (mV/nm) of the second hole-transport layer from GSP_slope (mV/nm) of the first hole-transport layer is less than or equal to 10 (mV/nm). Note that GSP_slope (mV/nm) is a parameter represented by V/d when surface potential and thickness of a film are V (mV) and d (nm), respectively.

Abstract: A novel light-emitting device is provided. A light-emitting device with high emission efficiency is provided. A light-emitting device with a long lifetime is provided. A light-emitting device with low driving voltage is provided. The light-emitting device includes an anode, a cathode, and an EL layer between the anode and the cathode. The EL layer includes a hole-injection layer, a light-emitting layer, and an electron-transport layer. The hole-injection layer is positioned between the anode and the light-emitting layer. The electron-transport layer is positioned between the light-emitting layer and the cathode. The hole-injection layer contains a first substance and a second substance. The first substance is an organic compound which has a hole-transport property and a HOMO level higher than or equal to ?5.7 eV and lower than or equal to ?5.4 eV. The second substance exhibits an electron-accepting property with respect to the first substance.

Abstract: A light-emitting element having high emission efficiency is provided. A light-emitting element having a low driving voltage is provided. A novel compound which can be used for a transport layer or as a host material or a light-emitting material of a light-emitting element is provided. A novel compound with a benzofuropyrimidine skeleton is provided. Also provided is a light-emitting element which includes the compound with the benzofuropyrimidine skeleton between a pair of electrodes.

Abstract: An organic semiconductor device with low driving voltage is provided. The light-emitting device includes an anode, a cathode, and an EL layer between the anode and the cathode. The EL layer includes a hole-transport layer and alight-emitting layer. The hole-transport layer is positioned between the anode and the light-emitting layer. The hole-transport layer is not in contact with the anode. The hole-transport layer includes a transport layer material for a light-emitting device and the GSP_slope that is a potential gradient of a surface potential of an evaporated film of the material is higher than or equal to 20 (mV/nm).

Abstract: A novel light-emitting device is provided. A light-emitting device with high emission efficiency is provided. A light-emitting device with along lifetime is provided. A light-emitting device with low driving voltage is provided. The light-emitting device includes an anode, a cathode, and an EL layer between the anode and the cathode. The EL layer includes a hole-injection layer, a light-emitting layer, and an electron-transport layer. The hole-injection layer is positioned between the anode and the light-emitting layer. The electron-transport layer is positioned between the light-emitting layer and the cathode. The hole-injection layer contains a first substance and a second substance. The first substance is an organic compound which has a hole-transport property and a HOMO level higher than or equal to ?5.7 eV and lower than or equal to ?5.4 eV. The second substance exhibits an electron-accepting property with respect to the first substance.

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 S1 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: A multicolor light-emitting element using fluorescence and phosphorescence, which has a small number of manufacturing steps owing to a relatively small number of layers to be formed and is advantageous for practical application can be provided. In addition, a multicolor light-emitting element using fluorescence and phosphorescence, which has favorable emission efficiency is provided. A light-emitting element which includes a light-emitting layer having a stacked-layer structure of a first light-emitting layer exhibiting light emission from a first exciplex and a second light-emitting layer exhibiting phosphorescence is provided.

Abstract: A novel light-emitting device is provided. A light-emitting device with high emission efficiency is provided. A light-emitting device with a favorable lifetime is provided. A light-emitting device with low driving voltage is provided. The light-emitting device includes an anode, a cathode, and an EL layer positioned between the anode and the cathode. The EL layer includes a hole-injection layer, a light-emitting layer, and an electron-transport layer. The hole-injection layer contains a hole-transport material and an electron-accepting material. The electron-transport layer contains an electron-transport material and an alkali metal itself, an alkaline earth metal itself, a compound of an alkali metal or an alkaline earth metal, or a complex thereof. The hole-injection layer has the spin density measured by an ESR method is lower than or equal to 1×1019 spins/cm3.

Abstract: A light-emitting layer, which is a stack of a first light-emitting layer and a second light-emitting layer, is provided between an anode and a cathode. The first light-emitting layer is formed on the anode side and contains a first light-emitting substance converting triplet excitation energy into light emission, a first organic compound having an electron-transport property, and a second organic compound having a hole-transport property. The second light-emitting layer contains a second light-emitting substance converting triplet excitation energy into light emission, the first organic compound, and a third organic compound having a hole-transport property. The second organic compound has a lower HOMO level than the third organic compound. The first light-emitting substance emits light with a wavelength shorter than that of light emitted from the second light-emitting substance. The first and the second organic compounds form an exciplex. The first and the third organic compounds form an exciplex.