First Principle Investigations of Cesium Based Cubic CsSiX3 (X = Cl and F) Perovskites for Solar Conversion Applications: A DFT Study

The use of solar water-splitting technology is anticipated to reduce the disparity between demand and consumption of energy. Herein, CASTEP software is used to investigate the perovskite CsSiX₃ (X = Cl and F) materials by applying GGA-PBE exchange–correlation functional. According to structure properties, compounds possess a cubic structure of “pm3m” by using space group 221. The direct band gaps in the CsSiX₃ (X = Cl and F) compounds are 1.04 and 1.07 eV, respectively. Measures of the density of states and the partial density of states (PDOS) are being utilized to determine the degree of electron localization in several bands. The compounds' optical characteristics are examined by altering their relation between the dielectric function (DF) scales and the pertinent peak. According to our results, the mechanical properties show that CsSiCl₃ is brittle (0.13, 045) and CsSiF₃ is ductile (0.32, 2.52) and stable with covalent bonds. Compounds CsSiCl₃ and CsSiF₃ modulus and elastic constants are {B (8.259, 52.375), E (8.110, 55.082), and G (18.331, 20.790)} and {C₁₁ (13.766, 73.566), C₁₂ (5.506, 41.780), and C₄₄ (10.763, 24.052)} are found, according to mechanical properties. Therefore, such materials can be used for photovoltaic light absorption in the visible spectrum. These materials offer a wide range of possible uses in sensing and solar conversion because compounds combine effectively.