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.