Effective defect passivation of CsPbBr3 quantum dots using gallium cations toward the fabrication of bright perovskite LEDs

Abstract

Inorganic metal halide perovskite quantum dots (QDs) have emerged as a new class of solution-processable semiconductor materials for next-generation displays. However, such QDs commonly suffer from surface defects, resulting in low photoluminescence quantum yields (PLQYs) and inefficient charge carrier transport in perovskite QD based light-emitting diodes (perovskite QD-based LEDs). Herein, we propose an effective strategy of introducing gallium (Ga) cations to passivate surface defects in the CsPbBr₃ QDs for the fabrication of bright perovskite QD-based LEDs. Partial Ga cations in the CsPbBr₃ QD surfaces are beneficial for their surface defect passivation and their crystalline quality. Correspondingly, the radiative recombination and carrier mobility are greatly enhanced compared with the pristine ones. The PLQY of CsPbBr₃ QDs passivated with 40% Ga cations is increased from 60.2% to 86.7%. The corresponding perovskite QD-based LEDs exhibit a maximum brightness of 11 777 cd m⁻², more than two times higher than that of the pristine QD-derived device. The corresponding operational stability is also greatly enhanced relative to the pristine-derived device. The proposed Ga cation passivation strategy paves the way toward the fabrication of highly efficient perovskite QD-based LEDs for applications such as perovskite QD-based LED displays and light conversion based micro-LED displays.