Theoretical investigation of the electronic structure and anisotropic optical properties of quasi-1D Sb2Se3 photovoltaic absorber materials

Sb2Se3 is a nontoxic, environmentally friendly photovoltaic absorber material with both a narrow bandgap and high absorption coefficient. The optical properties of Sb2Se3 crystals are theoretically studied herein using first-principles methods. The crystal structure, electronic structure, dielectric function, and absorption coefficient are calculated. The results show that the quasi-one-dimensional structure of Sb2Se3 has an indirect bandgap with a value of 0.953 eV. The bottom of the conduction band and the top of the valence band are mainly formed by Sb 5p and Se 4p hybridized orbitals. For light incident along the [100], [010], and [001] directions, the real and imaginary parts of the dielectric function exhibit clearly anisotropic characteristics. The absorption coefficient is greater than 105 cm−1.