Theoretical investigation of the electronic structure and anisotropic optical properties of quasi-1D Sb 2 Se 3 photovoltaic absorber materials

Sb 2 Se 3 is a nontoxic, environmentally friendly photovoltaic absorber material with both a narrow bandgap and high absorption coefficient. The optical properties of Sb 2 Se 3 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 Sb 2 Se 3 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 5 p and Se 4 p 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 10 5 cm −1 .