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

All-inorganic CsPbX3 perovskite quantum dots (QDs) have attracted extensive attention as the promising materials for new-generation optoelectronic applications. However, massive surface defects on CsPbX3 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 CsPbBr3 QDs via directly adding the ammonium hexafluorophosphate (NH4PF6) into the as-synthesized CsPbBr3 colloidal QDs. By virtue of the interaction between Pb2+ and PF6−, as well as the similar chemical properties of PF6− and halides, the post-synthetic NH4PF6 treatment is demonstrated to effectively passivate surface defects on CsPbX3 QDs and form the Br-rich organic-inorganic hybrid passivation mode. As a consequence, the NH4PF6-treated CsPbBr3 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 CsPbBr3 perovskite QDs with excellent PL and environmental stability, which will further promote their commercialization process.