An organic p-n junction for electrode-independent electron injection layer in organic light emitting diodes

Abstract

We demonstrated that an organic p–n junction was successfully adapted to inverted organic light emitting diodes (IOLEDs) as an electron injection layer (EIL). The organic p–n junction composed of a ReO₃ doped copper phthalocyanine (CuPc)/Rb₂CO₃ doped 4,7-diphenyl-1,10-phenanthroline (Bphen) layer showed very efficient charge generation under a reverse bias reaching to 100 mA/cm² at 0.3 V and efficient electron injection from indium tin oxide (ITO) when adopted in IOLEDs. Moreover, the organic p–n junction resulted in the same current density–voltage–luminance characteristics independent of the work function of the cathode, which is a valuable advantage for flexible displays.