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

摘要

It is an object of the present invention to provide a light-emitting element with high light emission efficiency and with a long lifetime. A light-emitting device comprises a first electrode, a second electrode, a light-emitting layer, a first layer, and a second layer, wherein the first layer is provided between the light-emitting layer and the first electrode, the second layer is provided between the light-emitting layer and the second electrode, the first layer is a layer for controlling the hole transport, the second layer is a layer for controlling the electron transport, and light emission from the light-emitting layer is obtained when voltage is applied to the first electrode and the second electrode so that potential of the first electrode is higher than potential of the second electrode.

主权项

1. An electronic device comprising:
a display portion; a memory portion; an operation switch; and a main body which includes the display portion, the memory portion, and the operation switch, wherein the display portion comprises a light-emitting element comprising:
a first electrode;a first layer over the first electrode;a light-emitting layer over the first layer;a second layer over the light-emitting layer, wherein the second layer comprises a first organic compound and a second organic compound; anda second electrode over the second layer, wherein the first layer comprises a third organic compound and a fourth organic compound, wherein the third organic compound has a hole transporting property, wherein the fourth organic compound has an electron transporting property, wherein a weight ratio of the first organic compound is higher than a weight ratio of the second organic compound, wherein the first organic compound has an electron transporting property, wherein the second organic compound has an electron trapping property, and wherein a lowest unoccupied molecular orbital level of the fourth organic compound is lower than a lowest unoccupied molecular orbital level of the third organic compound by 0.3 eV or more.