CuPc buffer layer role in OLED performance: a study of the interfacial band energies

We present a UV photoemission (UPS) and topographic study of the indium–tin-oxide (ITO) anode used in organic light emitting diodes (OLEDs). The performance of these devices has been shown to be improved by introducing a thin layer of copper phthalocyanine (CuPc) between the anode and the hole-transport layer (HTL). While the device current at constant driving voltage increases with increasing CuPc thickness, the efficiency is optimized at …