Facile Fabrication of Highly Stable and Wavelength-Tunable Tin Based Perovskite Materials with Enhanced Quantum Yield via the Cation Transformation Reaction.

Metal halide perovskites have attracted great attention for their superior light energy conversion applications. Herein, we demonstrated a facile synthesis of zero-dimensional Sn perovskite CsMSnBr(M = K and Rb) material through the cation transformation reaction at room temperature. CsSnBr NCs was mixed with pure metal bromide salts (KBr and RbBr) via the mechanochemical process to successfully synthesize CsMSnBr perovskite where transformation of Cs to mixed Cs/Rb and mixed Cs/K was achieved. By substituting different cations, the bright fluorescence of the CsMSnBr was tuned from dim green to greenish-cyan while achieving the photoluminescence (PL) quantum yield of ∼39%. The crystal structure of Sn based perovskite with the substitution of K or Rb cations was determined by X-ray diffraction (XRD). Moreover, the CsMSnBr demonstrated superior air stability and exhibited a better photocatalytic activity for CO reduction reaction (CORR) with high selectivity of CH gas with a higher yield rate compared to the pristine CsSnBr NCs.