Facile Fabrication of Highly-Stable and Wavelength-Tunable Tin based Perovskite Materials with Enhanced Quantum Yield via Cation Transformation Reaction
Jia-Ming Meng, Zhi-Xian Yang, Shivaraj B. Patil, Jou-Chun Lin, Chen-Hao Yeh, Yi-Chia Chen, Chih-Wen Pao, Jeng-Lung Chen, Wun-Yu Chen, Chin-Wei Lu, Tsung-Rong Kuo, and Di-Yan Wang*
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 Cs4-xMxSnBr6 (M= K+ and Rb+) material through cation transformation reaction at room temperature. Cs4SnBr6 NCs were mixed with pure metal bromide salts (KBr and RbBr) via mechanochemical process to successfully synthesize Cs4-xMxSnBr6 perovskite where transformation of Cs to mixed Cs/Rb and mixed Cs/K was achieved. By substituting different cations, the bright fluorescence of the Cs4-xMxSnBr6 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 were determined by X-ray diffraction (XRD). Moreover, the Cs4-xMxSnBr6 demonstrated superior air-stability and exhibited a better photocatalytic activity for CO2 reduction reaction (CO2RR) with high selectivity of CH4 gas with higher yield rate compared to the pristine Cs4SnBr6 NCs.