Influence of PVK: NPB hole transporting layer on the characteristics of organic light-emitting devices

Abstract

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer (CHTL). By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK:NPB are constructed. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m² and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK:NPB at 1:3.

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