First-principles prediction of asymmetric electronic structures, optoelectronic features, and efficiency for Sb2S3, Tl2S, TlSbS2, and TlSb3S5 compounds

In this study, the density functional theory calculations were used to calculate the electronic structures and optical properties of binary and ternary antimony chalcogenide compounds Sb2S3, Tl2S, TlSbS2, and TlSb3S5. The band structures and density of states have shown that the asymmetric densities in Sb2S3, TlSbS2, and TlSb3S5 compounds are due to the presence of 5s states of antimony-Sb. This asymmetric density is affected by the increase in the energy of the 3p valence state of the S element. The fundamental bandgaps were calculated, which revealed a direct semiconductor character in the middle of the Brillouin zone for TlSb3S5, whereas Sb2S3, Tl2S, and TlSbS2 exhibited an indirect semiconductor behavior. In addition, the changes in various optical quantities as a function of wavelength were also calculated and discussed to determine the optoelectronic efficiency of the studied compounds. •The Sb2S3, Tl2S, TlSbS2, and TlSb3S5 compounds have been investigated.•An asymmetric density in Sb2S3, TlSbS2, and TlSb3S5 compounds has been found•TlSb3S5,exhibits a direct bandgap whereas Sb2S3, Tl2S, and TlSbS2 exhibit an indirect bandgap.•The optical quantities as a function of wavelength have been analyzed.•The studied materials were identified as promising materials for electrical and optical applications.