Doping-induced phase transformation in all-inorganic perovskite CsPbI3 with enhanced structural and optical stability

Ambient stability is a serious unresolved issue with recently trending all-inorganic perovskite materials, especially CsPbI3 which has a high tendency to get converted from the black phase to the yellow delta or nonperovskite phase. So here we have demonstrated successful doping-induced phase transformation from the metastable mixed phase to the stable cubic phase CsPbI3 by optimizing its tolerance factor. Smaller size of dopant Cu atom in pristine CsPbI3 leads to a significant enhancement of the structural and optical stability of CsPbI3 which can thus be used for fabricating solar cells and other optoelectronic devices.