Owing to the nontoxicity and attractive optoelectronic properties, CsSnI3 is considered as a potential lead-free inorganic perovskite for solar energy applications. Despite these advantages, CsSnI3 photovoltaic cells have not existed until now, in some ways caused by low stability. Mixed cation strategy has been used to improve the stability of CsSnI3. However, the mixing anion strategy has not used in the design of lead-free inorganic perovskites for photovoltaic application. Herein, we execute a comprehensive study of a series of lead-free and mixed ion (Rb/Cs cation-exchange or Br/I anion-exchange) inorganic halide perovskite materials. We demonstrated that how gradual substitution of Rb for Cs and Br for I inﬂuences the structural, thermodynamic, and electronic properties by means of DFT-1/2 calculations including spin-orbit coupling. We also found that substitution of Br for I can prevent the unwanted g to Y phase transition which will notably decrease the efficiency of solar cell as mentioned in other work. Most importantly, we predict that CsSn(BrxI1-x)3 can possess a direct bandgap within the optimal range of 0.9−1.6 eV when x < 2/3, with favorable effective masses for high carrier mobility. This new lead-free inorganic perovskite may have great potential for the application of photovoltaic as an alternative, highly efficient solar absorber material.
|Title of host publication||Proceedings of International Conference on Perovskite Thin Film Photovoltaics, Photonics and Optoelectronics (ABXPV18PEROPTO) 2018|
|Publication status||Published - 2018|