Patent ID: 8778511

Claim:
An organic light emitting device, comprising: (a) an anode (b) a cathode (c) a first organic layer disposed between the anode and the cathode, the first organic layer being an emissive layer comprising a first organic emitting material; (d) a second organic layer disposed between the anode and the first organic layer and in direct contact with the first organic layer, the second organic layer being a non-emissive layer, the second organic layer comprising: (i) an organic small molecule hole transport material having a concentration of 50 to 99 wt %; (ii) an organic small molecule electron transport material having a concentration of 0.1 to 5 wt %; wherein the concentration of the 0.1 to 5 wt % of the organic small molecule electron transport material occurs at a position in the second organic layer immediately on the anode side of the emissive layer.