Metal oxide charge transport layer targeting efficient and stable perovskite light-emitting diodes

Abstract

The charge transport layer is a critical functional component in perovskite light emitting-didoes (PeLEDs). Metal oxide semiconductors (MOSs) are attractive charge transport materials owing to their advantages of robust stability, high carrier mobility, high transparency, as well as low cost. However, because of the complex mutual chemistry disturbance between the metal oxide and luminescent halide perovskites, there are severe charge quenching and even decomposition of the perovskite layers. Therefore, the advance of MOSs as charge transport layers in PeLEDs is still confined within selective cases. It is a prerequisite to gain depth insight into the interfacial contact between perovskites and MOSs from surface chemistry reactions and charge quenching before the realization of MOSs charge transport layers for constructing efficient and stable PeLEDs. In this review, we started with a brief introduction to perovskite materials and the development of PeLEDs. Then, we highlighted the importance of the interfacial contacts between perovskite and charge transport layers, followed by summarizing the progress of PeLEDs using MOSs as charge transport layers from the aspects of surface reaction, crystallization, quenching mechanism, charge injection, and operational stability. We also proposed possible research directions on engineering MOSs charge transport layers that would further improve the performance of PeLEDs.