Light-emitting element, light-emitting device, and electronic device

摘要

A light-emitting element includes a first electrode, a first light-emitting layer formed over the first electrode, a second light-emitting layer formed on and in contact with the first light-emitting layer to be in contact therewith, and a second electrode formed over the second light-emitting layer. The first light-emitting layer includes a first light-emitting substance and a hole-transporting organic compound, and the second light-emitting layer includes a second light-emitting substance and an electron-transporting organic compound. Substances are selected such that a difference in LUMO levels between the first light-emitting substance, the second light-emitting substance, and the electron-transporting organic compound is 0.2 eV or less, a difference in HOMO levels between the hole-transporting organic compound, the first light-emitting substance, and the second light-emitting substance is 0.2 eV or less, and a difference in LUMO levels between the hole-transporting organic compound and the first light-emitting substance is greater than 0.3 eV.

主权项

1. A light-emitting element comprising:
a first electrode; a first light-emitting layer formed over the first electrode; a second light-emitting layer formed on and in contact with the first light-emitting layer; and a second electrode formed over the second light-emitting layer, wherein the first light-emitting layer includes a first light-emitting substance and a hole-transporting organic compound, wherein the second light-emitting layer includes a second light-emitting substance and an electron-transporting organic compound, wherein the hole-transporting organic compound is a compound represented by a general formula (1) below, and wherein, in the general formula (1), A represents any one of a substituted or unsubstituted phenyl group and a substituted or unsubstituted naphthyl group, and each of R1 and R2 represents any one of hydrogen, an alkyl group including 1 to 4 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, and a substituted or unsubstituted carbazolyl group.