Vapor Transport Deposition of Sb₂(S,Se)₃ Solar Cells with Continuously Tunable Band Gaps

Antimony chalcogenide (Sb2(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 Sb2(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 Sb2(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 Sb2(S,Se)3 single-junction solar cell. This study proposed a reliable way to achieve various Sb2(S,Se)3 films with designated band gaps for the demand of multijunction solar cells.