Modeling charge transport mechanism in inorganic quantum dot light-emitting devices through transport layer modification strategies

Abstract

Quantum dot light-emitting devices (QLEDs) are potential candidates for lighting and display applications. The charge transport mechanism which plays an essential part in the performance of these devices, however, needs to be explored and analyzed for further improvement. The imbalance of the injection and transport of charge carriers within the device adversely affects the efficiency and stability of the device. Charge balance can be improved by better charge injection of holes while suppressing the excessive electrons. A simple and effective strategy to achieve this is using double transport layers or doped transport layers to modulate the band alignment and injection of charge carriers. Here, we propose a new structure and investigate the physical processes within a QLED with a double hole transport layer for improved charge injection of holes and a doped electron transport layer for controlled charge injection of electrons. We find that the process of charge injection, tunneling, and recombination is significantly improved within the quantum dot layer and a better charge balance is achieved in the emissive layer. Through the theoretical simulation model, useful results are obtained which pave the way for designing high-performing QLEDs.