High‐Performance Inverted Tandem OLEDs with the Charge Generation Layer based on MoOx and Ag Doped Planar Heterojunction

Abstract The morphological and electrical characteristics of a planar‐heterojunction structured charge generation layer (CGL) consisting of MoO 3 doped N , N ′‐bis‐(1‐naphthalenyl)‐ N , N ′‐bis‐phenyl‐(1,1′‐biphenyl)‐4,4′‐diamine (NPB) as the p ‐type material and Ag‐doped 4,7‐diphenyl‐1,10‐phenanthroline (Bphen) as the n ‐type counterpart (NPB:MoO 3 /Bphen:Ag). A significant charge generation effect of CGL is observed and its mechanism is analyzed. The introduction of CGL can enhance the concentration of the charge carrier and balance the injection of carriers. Inverted tandem organic light‐emitting diodes (OLEDs) with the CGL are fabricated. The inverted tandem OLEDs exhibit excellent optoelectronic performance due to the charge generation effect and the suppression of the high concentration quenching. The maximum current efficiency and external quantum efficiency of the inverted tandem OLED reached 27.91 cd A −1 and 11.18%, respectively, which are 110.95% and 95.79% higher than that of the inverted OLED.