Role of carrier mobility, exciton diffusion, and their interplay for charge balance and improved properties of organic electrophosphorescent device

Abstract

In this paper, we demonstrated that controlled charge trapping, both at the emission layer and charge transport layer with energy level alignment, is essential for charge-balanced and effective electrophosphorescent organic light-emitting device (OLED). Conditions for enhanced of efficiency and lifetime of OLED were obtained with graded doping profile at the light-emission layers (varied host-dopant concentration) and different hole (exciton) blocking materials. Conceptual device physics presented in this study can be applied at an initial design of charge-confined, balanced structure of highly efficient electrophosphorescent devices.