High-Efficiency Semitransparent Solar Cells Based on Magnetron Sputtered Sb₂S₃ Thin Films

Thin-film solar cells based on wide-bandgap antimony sulfide (Sb₂S₃) offer new possibilities for semitransparent building-integrated photovoltaics. In this report, impurity-free Sb₂S₃ thin films are prepared by radio frequency magnetron sputtering. The optimized opaque devices obtain a high power conversion efficiency (PCE) of 4.6%. A detailed characterization is conducted to investigate the impact of annealing conditions on the morphology, crystal structure, composition, and optoelectronic properties of Sb₂S₃ thin films, which are relevant to photovoltaic performance. Moreover, semitransparent solar cells are fabricated using highly compact Sb₂S₃ films with thicknesses of 40, 60, and 80 nm. Using a superstrate device structure (FTO/TiO₂/Sb₂S₃/P3HT-PEDOT:PSS/Au (≈10 nm)), these solar cells achieve PCEs of 2.0%, 2.6%, and 3.2%, respectively, while maintaining an average visible transmittance (AVT) of 15.5%, 13.5%, and 10.0%. The AVTs of the semitransparent devices are further enhanced by replacing the ultrathin Au top electrode with indium-doped tin oxide and using wide bandgap inorganic CuSCN as the hole transport layer instead of P3HT-PEDOT:PSS. Thus, the AVT improves to 20.5% (PCE: 2.0%) for semitransparent solar cells using 60 nm Sb₂S₃. This study demonstrates that sputtering is a promising deposition technique for high-quality ultrathin Sb₂S₃ absorbers for semitransparent photovoltaics.