Patent ID: 9647227
Date: 2017-05-09
CPC Classifications: C09K,H01L,H05B

Claim:
1. An organic light emitting device comprising an emissive region, wherein the emissive region comprises: a first emissive layer comprising a fluorescent blue emitting material as a dopant in a host material; a spacer layer; a second emissive layer comprising a phosphorescent emitting material as a dopant in a host material, wherein the spacer layer is between the first emissive layer and the second emissive layer, wherein the spacer layer inhibits quenching of the triplet excitons in the second emissive layer, wherein an interface between the spacer layer and one of the first and second emissive layers forming a heterojunction, and wherein the spacer layer comprises a material that has a triplet energy that is higher than the triplet energy of the phosphorescent emitting material, wherein one of the following is true: (a) the phosphorescent emitting material in the second emissive layer is a phosphorescent green emitting material and the second emissive layer further comprises a phosphorescent red emitting material as a second dopant; (b) the phosphorescent emitting material in the second emissive layer is a phosphorescent green emitting material and the emissive region further comprises a third emissive layer on the same side of the spacer layer as the second emissive layer, wherein the third emissive layer comprises a phosphorescent red emitting material as a dopant in a host material; or (c) the phosphorescent emitting material in the second emissive layer is a phosphorescent red emitting material and the first emissive layer further comprises a fluorescent green emitting material as a second dopant.