Facile Fabrication of Highly Stable and Wavelength-Tunable Tin Based Perovskite Materials with Enhanced Quantum Yield...

Metal halide perovskites have attracted great attention for their superior light energy conversion applications. Herein, we demonstrated a facile synthesis of zero-dimensional Sn²⁺ perovskite Cs_4-MSnBr₆(M = K⁺ and Rb⁺) material through the cation transformation reaction at room temperature. Cs₄SnBr₆ NCs was mixed with pure metal bromide salts (KBr and RbBr) via the mechanochemical process to successfully synthesize Cs_4-MSnBr₆ perovskite where transformation of Cs to mixed Cs/Rb and mixed Cs/K was achieved. By substituting different cations, the bright fluorescence of the Cs_4-MSnBr₆ 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 Cs_4-MSnBr₆ demonstrated superior air stability and exhibited a better photocatalytic activity for CO₂ reduction reaction (CO₂RR) with high selectivity of CH₄ gas with a higher yield rate compared to the pristine Cs₄SnBr₆ NCs.