Novel organic electron injection layer for efficient and stable organic light emitting diodes

The efficiency of organic light-emitting diodes (OLEDs) was significantly improved by introducing a novel organic composition (4,7-diphyenyl-1,10-phenanthroline (BPhen): 20 wt% tetracyanoquinodimethane (TCNQ)) as an electron injection layer which could be uniformly deposited over a range of thicknesses. A highly injecting contact was obtained using 1.5 nm thick film of 20 wt% TCNQ mixed BPhen as the electron injection layer. High efficiency and stability of organic light emitting device are ascribed to improved electron injection and hence better charge carrier balance inside the OLEDs.