Light-Emitting Element, Lighting Device, Light-Emitting Device, and Electronic Device

摘要

A light-emitting element with high emission efficiency is provided. A light-emitting element with a long lifetime is provided. The light-emitting element includes an anode; a hole-transport layer over the anode, containing a hole-transport compound and a compound; a light-emitting layer over the hole-transport layer, containing a host material and a guest material; and a cathode over the light-emitting layer. The host material is an electron-transport compound. The guest material and the compound are each independently a phosphorescent compound or a thermally activated delayed fluorescence material. A peak of an emission spectrum of the compound is on a shorter wavelength side than a peak of an emission spectrum of the guest material. Only the guest material emits light.

主权项

1. A light-emitting element comprising:
an anode; a hole-transport layer over the anode, the hole-transport layer containing a hole-transport compound and a first compound; a light-emitting layer over the hole-transport layer, the light-emitting layer containing a host material and a guest material; and a cathode over the light-emitting layer, wherein the first compound is any one of a phosphorescent compound and a thermally activated delayed fluorescence material, wherein the host material is an electron-transport compound, wherein the guest material is any one of a phosphorescent compound and a thermally activated delayed fluorescence material, wherein a peak of an emission spectrum of the first compound is on a shorter wavelength side than a peak of an emission spectrum of the guest material, and wherein only the guest material emits light.