Amine- and Acid-Free Synthesis of Stable CsPbBr3 Perovskite Nanocrystals

Ligands binding to all-inorganic lead halide perovskite nanocrystals (IPNCs) are easy to detach from the surface through proton exchange, causing severe stability issue in practical application. Here, we reported an amine- and acid-free approach for synthesis of CsPbBr3 IPNC with highly improved photochemical stability. The reaction mechanism follows a trioctylphosphine-mediated surface passivation route, which provides a proton-free reaction environment to stabilize the ligand capping on the surface of IPNCs. NMR, FTIR, XPS characterizations reveal that the IPNCs possess a lead-rich surface passivated by carboxylate. The surface capping motif endows IPNCs with comprehensively improved stability against air, water, light and heat. The IPNCs withstand exposure to ethanol in room light for 30 days and show nearly no fluorescent quenching. More importantly, the IPNCs present high resistance to intense light irradiation. Under continuous irradiation by 10W/cm2 blue light in open air, the lifetime of the IPNCs...