A comprehensive ab-initio study of Cs3Sb2X9 (X= Cl, Br) novel halide perovskites for solar cell applications

Two-dimensional perovskite materials have recently attracted significant interest in solar cell applications. This study employed DFT calculations to investigate the structural, electronic, optical, magnetic, thermal properties and spectroscopic limited maximum efficiency (SLME) of Cs3Sb2X9 (X = Cl, Br) perovskites. The dynamic vibrational stability was calculated using the phonon energy dispersion curve; results show that Cs3Sb2X9 (X = Cl, Br) is dynamically stable. The electronic band structure revealed that these materials exhibit semiconductor behavior with energy bandgaps of 2.41 eV and 1.77 eV for Cs3Sb2Cl9 and Cs3Sb2Br9, respectively. The Cs3Sb2Br9 shows higher absorption and conductivity at comparatively lower frequencies of absorbed light. Furthermore, the magnetic characteristics of the investigated compounds demonstrate that there are no net magnetic moments. The thermodynamic properties analysis indicated a strong correlation between heat capacity and temperature. We have used SLME analysis to determine the theoretical power conversion efficiency for Cs3Sb2X9 (X = Cl, Br) perovskites. The determined results of SLME show that Cs3Sb2Cl9 and Cs3Sb2Br9 exhibit SLME values of 12.63 % and 26.40 %, respectively, at 298.15 K, suggesting that both compounds can be used in solar cells.