Compositional Engineering of Antimony Chalcoiodides via a Two-Step Solution Process for Solar Cell Applications

Antimony chalcoiodide, Sb(S,Se)I, has recently gained considerable attention as an alternative to Pb-based perovskites in next-generation solar cells. In this work, we propose an effective solution-processing method for fabricating Sb(S,Se)I alloy films with various S/Se ratios for solar cell applications. The proposed method involves two steps: the formation of Sb2(S,Se)3 (step I) and its conversion to Sb(S,Se)I (step II). We introduced an additional deposition step based on a SbCl3-selenourea solution in step I to fabricate Sb(S,Se)I alloy with tunable properties. We controlled the growth of Sb(S1–xSex)I films (0 ≤ x ≤ 1) and investigated the effects of the S/Se molar ratio on the bandgap, crystalline phase, morphology, and electronic structure. Further, based on the results, we propose suitable electron- and hole-transporting layers for constructing antimony chalcoiodide solar cells. This study highlights the potential of Sb(S,Se)I as a solar absorber and provides some clues to construct Sb(S,Se)I solar cells.