Patent ID: 7504163

Claim:
An organic light-emitting device comprising a blue or blue-green light-emitting layer, including a host, a dopant and a hole-trapping material having an amine moiety, wherein the hole-trapping material is provided at 0.01% to less than 5% by volume relative to the light-emitting layer volume, has an oxidation potential that is selected so that it is less than the oxidation potential of the host in order to serve as a hole trap, has an oxidation potential that is selected so as to avoid formation of a certain charge transfer complex between the hole-trapping material and the host if the charge transfer complex causes a reduction in the electroluminescent efficiency of the dopant, and has an oxidation potential that is selected so as to avoid formation of an undesirable charge transfer complex between the hole-trapping material and the dopant wherein the oxidation potential for the hole-trapping material is in a range of from +0.6 V to +1.1 V, while the oxidation potential for the host is +1.2 V or higher vs. SCE.