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

ABSTRACT 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 CsSiX 3 (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 CsSiX 3 (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 CsSiCl 3 is brittle (0.13, 045) and CsSiF 3 is ductile (0.32, 2.52) and stable with covalent bonds. Compounds CsSiCl 3 and CsSiF 3 modulus and elastic constants are { B (8.259, 52.375), E (8.110, 55.082), and G (18.331, 20.790)} and { C 11 (13.766, 73.566), C 12 (5.506, 41.780), and C 44 (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.