Patent ID: 7683536
Filing Date: 2010-03-23
Classification: H01L,Y10T

Abstract:
1. An organic light emitting device comprising: a) an anode; b) a cathode; c) an emissive layer disposed between the anode and the cathode, the emissive layer comprising i) a phosphorescent dopant having a phosphorescent dopant HOMO energy level, a phosphorescent dopant LUMO energy level, a triplet energy, and a singlet energy; and ii) an emissive layer host having an emissive layer host HOMO energy level and an emissive layer host LUMO energy level; and d) a transport layer disposed adjacent to the emissive layer, the transport layer comprising a first material having a first material HOMO energy level and a first material LUMO energy level, wherein electrons and holes introduced into the emissive layer have an energy difference less than the energy required to form a singlet on the dopant, such that the energy difference is sufficient for formation of triplets on the dopant and energetically unfavorable for formation of singlets on the dopant.