Patent ID: 8476624

Claim:
An organic light emitting diode (OLED) device, comprising: (a) a substrate; (b) a cathode formed on the substrate; (c) a first electroluminescent unit formed on the cathode; (d) a charge generation layer (CGL) formed on the first electroluminescent unit; (e) a second electroluminescent unit formed on charge generation layer; and (f) an anode formed on the second electroluminescent unit, wherein each of the first and second electroluminescent units comprises an electron-transport layer (ETL), an emission layer (EML) formed on the electron-transport layer, and a hole-transport layer (HTL) formed on the emission layer, such that the electron-transport layer of the first electroluminescent unit is formed on the cathode, defining a first energy barrier, and the anode is formed on the hole-transport layer of the second electroluminescent unit, defining a second energy barrier, wherein the first energy barrier is higher than the second energy barrier, and wherein the first electroluminescent unit has a lifetime longer than that of the second electroluminescent unit.