Iridium complex, light-emitting element, display device, electronic device, and lighting device

A light-emitting device comprising:

• a light-emitting layer between a pair of electrodes,
• wherein the light-emitting layer comprises a first organic compound, a second organic compound, and a phosphorescent compound,
• wherein the first organic compound comprises a pyrimidine derivative or a triazine derivative,
• wherein a LUMO level of the first organic compound is lower than a LUMO level of the second organic compound,
• wherein a HOMO level of the first organic compound is lower than a HOMO level of the second organic compound,
• wherein an energy difference between a LUMO level of the phosphorescent compound and a HOMO level of the phosphorescent compound is larger than an energy difference between the LUMO level of the first organic compound and the HOMO level of the second organic compound,
• wherein the first organic compound and the second organic compound form an exciplex,
• wherein the energy difference between the LUMO level of the first organic compound and the HOMO level of the second organic compound is larger than or equal to a transition energy obtained from the absorption edge of the phosphorescent compound, and
• wherein an energy difference between the LUMO level of the phosphorescent compound and the LUMO level of the first organic compound is larger than or equal to 0.1 eV.

A light-emitting device comprising:

• a light-emitting layer between a pair of electrodes,
• wherein the light-emitting layer comprises a first organic compound, a second organic compound, and a phosphorescent compound,
• wherein the first organic compound comprises a pyrimidine derivative or a triazine derivative,
• wherein the second organic compound comprises a carbazole derivative,
• wherein a LUMO level of the first organic compound is lower than a LUMO level of the second organic compound,
• wherein a HOMO level of the first organic compound is lower than a HOMO level of the second organic compound,
• wherein an energy difference between a LUMO level of the phosphorescent compound and a HOMO level of the phosphorescent compound is larger than an energy difference between the LUMO level of the first organic compound and the HOMO level of the second organic compound,
• wherein the first organic compound and the second organic compound form an exciplex, and
• wherein an energy difference between the LUMO level of the phosphorescent compound and the LUMO level of the first organic compound is larger than or equal to 0.1 eV.