Effective Masses and Electronic and Optical Properties of Nontoxic MASnX₃ (X = Cl, Br, and I) Perovskite Structures as Solar Cell Absorber: A Theoretical Study Using HSE06

We calculated the effective masses and electronic and optical properties of CH 3 NH 3 SnX 3 (X = Cl, Br, I) perovskites as a solar cell absorber using the HSE06 hybrid functional. The computed band gaps are direct at the Γ point, ranging from 1.67 to 3.0 eV. The effective masses of carriers and the band gaps decrease from chlorine to iodine. Moreover, their hole masses are comparable to those of CH 3 NH 3 PbX 3 (X = Br and I) phases. The optical dielectric constant does not decrease monotonically when going from X = Cl to Br to I for CH 3 NH 3 SnX 3 perovskites. Under a small isotropic compressive stress, the photon absorption efficiency of CH 3 NH 3 SnX 3 perovskites is slightly improved due to the reduction of the fundamental band gap.