Vapor Transport Deposition of Sb-2(S,Se)(3) Solar Cells with Continuously Tunable Band Gaps

Antimony chalcogenide (Sb-2(S,Se)(3)) semiconductors have been demonstrated as a promising absorber material for highly efficient inorganic solar cells. Especially, tunable band gaps make them fascinating in the photovoltaic field, thanks to the reciprocal replacement of Se and S atoms. Herein, a series of Sb-2(S,Se)(3) films with continuously tunable band gaps were reported through a typical vapor transport deposition process. We concluded the relationship of the Se/S ratio between the evaporation source and the deposited film and successfully modified the structural and optical properties of the deposited Sb-2(S,Se)(3) films with a regulation of the Se/S ratio in the evaporation source. We found that interfacial diffusion during the deposition process was destructive to the device performance. With an optimization of the band gap, a power conversion efficiency of 7.1% was obtained for the Sb-2(S,Se)(3) single-junction solar cell. This study proposed a reliable way to achieve various Sb-2(S,Se)(3) films with designated band gaps for the demand of multijunction solar cells.