Rod-shaped thiocyanate-induced abnormal band gap broadening in SCN− doped CsPbBr3 perovskite nanocrystals
pseudohalide thiocyanate, doping, perovskite nanocrystals, cesium lead halide
ABSTRACT In this work, the pseudohalide thiocyanate has been demonstrated as a promising alternative to the halide anion to engineer optoelectronic properties of inorganic/ organic hybrid perovskites because it exhibits better chemical stability than the halide anion. Previous reports have suggested that the ionic radii and electronegativity of SCN− is close to that of I−; the SCN− doped CH3NH3PbI3 exhibited similar optical properties as pure CH3NH3PbI3. Consequently, it was expected that doping of CsPbBr3 perovskite with SCN− would result in band gap narrowing. Interestingly, the photoluminescent all-inorganic CsPbBr3 perovskite nanocrystals exhibit an abnormal blue shift in optical properties and improvement of the crystallinity when successfully doped by SCN−. Combined experimental and theoretical investigations revealed that doping of the CsPbBr3 perovskite with the rod-like SCN− anion introduced disorder in the crystal lattice, leading to its expansion, and impacted the electronic structure of the perovskite with band gap broadening.
Tsinghua University Press
Yongbing Lou,Yandan Niu,Dongwen Yang,Qiaoling Xu,Yuhang Hu,Ying Shen,Jing Ming,Jinxi Chen,Lijun Zhang,Yixin Zhao, Rod-shaped thiocyanate-induced abnormal band gap broadening in SCN− doped CsPbBr3 perovskite nanocrystals. NanoRes.2018, 11(5): 2715–2723