Abstract

In this research, first-principle density functional theory calculation was used to determine the structural, electronic and optical properties of ternary and quaternary chalcogenide perovskite compounds (BaTiS3, BaTiSSe2 and BaTiS2Se). Bandgaps of 1.61 eV, 0.54 eV and 1.39 eV were obtained for the three compounds respectively. These band gap values show that BaTiS3 and BaTiS2Se are ideal for photovoltaic applications. The high absorptance of 7 x 10 8 m -1 , 7 x 10 8 m -1 and 6.8 x 10 8 m -1 , low reflectivity of 0.7, 0.72 and 0.68, refractive index of 8.2, 8.8 and 8.2, and dielectric function of 78, 87 and 69 values respectively show that these compounds are good light absorbers.