Patent ID: 9705092
Date: 2017-07-11
CPC Classifications: C09K,H01L,H05B

Claim:
1. An organic light emitting device comprising an anode, a cathode and a plurality of organic layers sandwiched between them, the plurality of organic layers comprising: an emitter layer comprising a host material and a phosphorescent emitter material, the phosphorescent emitter material comprising a phosphorescent organometallic compound that emits phosphorescent radiation from a triplet molecular excited state when a voltage is applied across the first organic layer; a first hole transport layer disposed between the emitter layer and the anode, the first hole transport layer comprising a first hole transport material represented by the following general formula (HTL1)  wherein R Ar a second hole transport layer disposed between the first hole transport layer and the anode whereby the first hole transport layer is next to the emitter layer between the emitter layer and the second hole transport layer, wherein the second hole transport layer comprising a second hole transport material that is different from the first hole transport material; wherein the first hole transport material has a triplet energy that is higher than that of the second hole transport material; and wherein the phosphorescent organometallic compound is a heteroleptic compound represented by the formula L