Improved Charge Balance in Green Perovskite Light=Emitting Diodes with Atomic=Layer=Deposited Al₂O₃

Perovskite light=emitting diodes (LEDs) have experienced a rapid increase in efficiency over the last several years and are now regarded as promising low=cost devices for displays and communication systems. However, it is often challenging to employ ZnO, a well=studied electron transport material, in perovskite LEDs due to chemical instability at the ZnO/perovskite interface and charge injection imbalance caused by the relatively high conductivity of ZnO. In this work, we address these problems by depositing an ultrathin Al₂O₃interlayer at the ZnO/perovskite interface, allowing the fabrication of green=emitting perovskite LEDs with a maximum luminance of 21815 cd/m². Using atomic layer deposition, we can precisely control the Al₂O₃thickness and thus fine=tune the electron injection from ZnO, allowing us to enhance the efficiency and operational stability of our LEDs.