Photo-stability of CsPbBr3 perovskite quantum dots for optoelectronic application

Abstract

Due to their superior photoluminescence (PL) quantum yield (QY) and tunable optical band gap, all-inorganic CsPbBr3 perovskite quantum dots (QDs) have attracted intensive attention for the application in solar cells, light emitting diodes (LED), photodetectors and laser devices. In this scenario, the stability of such materials becomes a critical factor to be revealed. We hereby investigated the long-termstability of as-synthesized CsPbBr3 QDs suspended in toluene at various environmental conditions. We found light illumination would induce drastic photo-degradation of CsPbBr3QDs. The steady-state spectroscopy, transmission electron microscopy (TEM), and X-ray diffraction (XRD) verified that CsPbBr3 QDs tend to aggregate to form larger particles under continuous light soaking. In addition, decreasing PL QY of the QDs during light soaking indicates the formation of trap sites. Our work reveals that the main origin of instability in CsPbBr3 QDs and provides reference to engineer such QDs towards optimal device application.