Post-synthetic ammonium hexafluorophosphate treatment enables CsPbBr3 perovskite quantum dots exhibiting robust photoluminescence and environmental stability for white light-emitting diodes

All-inorganic CsPbX 3 perovskite quantum dots (QDs) have attracted extensive attention as the promising materials for new-generation optoelectronic applications. However, massive surface defects on CsPbX 3 QDs usually result in the inferior photoluminescence (PL) and environmental stability, severely hindering their real applications. For this sake, herein, an effective and low-cost post-synthetic treatment is employed to improve the optical properties and colloidal stability of CsPbBr 3 QDs via directly adding the ammonium hexafluorophosphate (NH 4 PF 6 ) into the as-synthesized CsPbBr 3 colloidal QDs. By virtue of the interaction between Pb 2+ and PF 6 − , as well as the similar chemical properties of PF 6 − and halides , the post-synthetic NH 4 PF 6 treatment is demonstrated to effectively passivate surface defects on CsPbX 3 QDs and form the Br-rich organic-inorganic hybrid passivation mode. As a consequence, the NH 4 PF 6 -treated CsPbBr 3 QDs robust PL emission and long-term stability, which can be successfully applied in white light-emitting diodes (WLEDs), showcasing bright practical application potentials. Our work provides a novel and simple strategy for preparing CsPbBr 3 perovskite QDs with excellent PL and environmental stability, which will further promote their commercialization process.