Efficient Copper-Doped Antimony Sulfide Thin-Film Solar Cells via Coevaporation Method

Sb 2 S 3 being a light-absorbing material is used for photovoltaic (PV) application due to its superior stability and progressive power conversion efficiency (PCE) benefiting from its low cost, less toxic, earth-abundant, and facile nature. Due to the difficulty in efficient doping for such 1D structure, the performance of as-fabricated thin-film solar cells is limited by high resistivity and hole extraction barrier. Herein, a coevaporation scheme is introduced for copper-doped Sb 2 S 3 by rapid thermal evaporation (RTE). The Cu-doped Sb 2 S 3 thin film discloses the enhanced crystallinity with a grain diameter greater than 1 µm and conductivity along with improved carrier concentration. At the same time, the deep valance band obtains a minor upshift, favoring the hole extraction at back contact. Consequently, all the PV parameters are enhanced leading to the PCE boosting from 4.18% to 4.61%. Herein, a facile doping technique is demonstrated to improve its performance without any modification of the present RTE method.