Patent ID: 9666822
Date: 2017-05-30
CPC Classifications: H01L

Claim:
1. An organic light emitting device comprising: an anode; a cathode; a first emissive layer disposed between the anode and the cathode, the first emissive layer comprising an electron transporting compound and a phosphorescent emissive dopant compound; wherein the phosphorescent emissive dopant compound is a hole transporter; and wherein the phosphorescent emissive dopant compound has a concentration gradient, in the emissive layer, wherein the concentration gradient varies according to a profile selected from the group consisting of: (i) linear towards the cathode side of the first emissive layer; (ii) non-linear towards the cathode side of the first emissive layer, wherein said non-linear profile corresponds to a polynomial function selected from the group consisting of a quadratic function, a cubic function, or a higher order function; and (iii) a step wise form.