Ab initio insight into the structural, vibrational, electronic, optical, magnetic, and thermal properties of lead-free perovskite Cs3Sb2Cl9 for solar cell application

In recent years, semiconducting lead (Pb) free perovskite materials have become more attractive materials due to their less toxicity. In this study, we have investigated structural, electronic, optical, magnetic, and thermal properties of Pb-free Cs3Sb2Cl9 perovskite material using density functional theory. We have calculated the Energy-Volume (E-V) curve to evaluate the structural stability. The estimated lattice parameters for the studied material are a = b = 7.818 Å and c = 9.436 Å. Electronic properties suggest that Cs3Sb2Cl9 is a semiconductor material with a suitable energy band gap (Eg = 3.214 eV) for solar cell applications. Optical properties like high absorption, high optical conductivity, and peak reflectivity value in the visible region suggest that Cs3Sb2Cl9 is the most promising material for photovoltaic applications. Furthermore, the dynamic vibrational stability has been investigated as a calculated phonon energy dispersion curve, which shows that Cs3Sb2Cl9 is a dynamically stable compound. The spin-polarized calculations show that the material as a whole and even at the elemental bands level has zero resultant magnetic moments. We have also calculated thermodynamic properties, including enthalpy, free energy, and entropy. Therefore, the calculated results suggest that Cs3Sb2Cl9 is a potential candidate for solar cell applications.