LIGHT-EMITTING ELEMENT, LIGHT-EMITTING DEVICE, DISPLAY DEVICE, LIGHTING DEVICE, AND ELECTRONIC DEVICE

摘要

Provided is a light-emitting element which has an anode, a light-emitting layer over the anode, an electron-transport layer over and in contact with the light-emitting layer, an electron-injection layer over and in contact with the electron-transport layer, and a cathode over and in contact with the electron-injection layer. The light-emitting layer has an electron-transport property, and the electron-transport layer includes an anthracene derivative. The light-emitting layer further includes a phosphorescent substance. This device structure allows the formation of a highly efficient blue-emissive light-emitting element even though the phosphorescent substance has higher triplet energy than the anthracene derivative which directly contacts with the light-emitting layer.

主权项

1. A light-emitting device comprising:
an anode; a light-emitting layer over the anode, the light-emitting layer comprising a host material and a phosphorescent substance; an electron-transport layer over and in contact with the light-emitting layer, the electron-transport layer comprising a first organic compound which has an anthracene skeleton and one of a carbazolyl skeleton and a dibenzo[c,g]carbazolyl skeleton; an electron-injection layer over and in contact with the electron-transport layer, the electron-injection layer comprising a second organic compound which is different from the first organic compound; and a cathode over and in contact with the electron-injection layer, wherein the host material is a π-electron deficient heteroaromatic compound.