Electronic structure and optical anisotropy in Sr1−x BaxFBiS2 (x = 0, 0.25, 0.5, 0.75, 1) based solar cell materials

•The doping effect on the physical properties of SrFBiS2 parent compound derived from BiS2 layers is examined.•It is found that the maximum absorption coefficient changes with the variation of Ba concentration in these systems.•A superior birefringence occurred in the concerned Sr1−xBaxFBiS2 alloys with the variation of composition x.•The optical spectra of all Sr1−xBaxFBiS2 alloys exhibited a high anisotropy.•A higher reflectivity and optical conductivity occur in the range of IR-visible-UV for Sr1−xBaxFBiS2 alloys.