Patent ID: 9059430
Filing Date: 2015-06-16
Classification: C09K,H01L

Abstract:
1. A light-emitting device comprising: a first light-emitting layer over an anode, the first light-emitting layer comprising a first phosphorescent compound, a first organic compound having an electron-transport property, and a second organic compound having a hole-transport property; a second light-emitting layer over the first light-emitting layer, the second light-emitting layer comprising a second phosphorescent compound, the first organic compound, and the second organic compound; and a cathode over the second light-emitting layer, wherein an emission spectrum of an exciplex of the first organic compound and the second organic compound overlaps with an absorption band on the longest wavelength side in an absorption spectrum of each of the first phosphorescent compound and the second phosphorescent compound, and wherein the first light-emitting layer comprises a higher proportion of the second organic compound than the second light-emitting layer.