Near-Unity Photoluminescence Quantum Yield in CsPbBr3 Nanocrystal Solid-State Films via Postsynthesis Treatment with Lead Bromide

Abstract

Metal halide perovskite nanocrystals (NCs) possess high photoluminescence (PL) quantum yield (PL) and color tunability. Yet, until now, it has been difficult to maintain the high PL observed in solution in spin-coated films. Here, we report a novel CsPbBr3 NCs room-temperature synthesis based on Cs acetate, which displays near-unity PL in solid-state films upon post-synthetic treatment with lead bromide. The as-synthesized NCs show a PL of 80% in spin-coated films but the post-synthesis treatment further enhances the efficiency >95%. The high PL is further confirmed by the monomolecular decay of the PL (5.8 ns) indicating a nearly complete suppression of non-radiative channels. The obtained films demonstrate high stability in air and require around 3 weeks to decrease to half the initial PL value.