A Hybrid Functional Study on Perovskite-Based Compounds CsPb_1-αZn_αI_3-βX_β (X = Cl or Br)

Inorganic perovskites have attracted a great deal of attention because of their stability. Unfortunately, a weak optical response and the toxicity of lead are hampering their development. Motivated by these facts, we focus herein on the perovskite-based doped series CsPb_1-αZn_αI_3-βX_β (X = Cl or Br). The geometric structures and the electronic and optical properties of CsPb_1-αZn_αI_3-βX_β (X = Cl or Br) are investigated systematically by hybrid functional theory. Analysis of the electronic properties indicates that Zn/Cl/Br mono-doping and co-doping efficiently tune bandgaps. Moreover, we find that the ability to obtain electrons for CsPb_0.625Zn_0.375I₂Cl is superior to the abilities of the others, which implies a stronger electron transition. In addition, CsPb_0.625Zn_0.375I₂Cl and CsPb_0.625Zn_0.375I₂Br show stronger visible-light responses in the range of 467-780 nm. Both CsPb_0.625Zn_0.375I₂Cl and CsPb_0.625Zn_0.375I₂Br are hence good choices for photovoltaic applications. Furthermore, the physically accessible region is also explored herein. These findings shed new light on the design of highly efficient and low-lead perovskite-based optoelectronic materials.