Facile Fabrication of an SnSx‐SnO2‐Decorated Cobalt Sulfide Film as an Effective Counter Electrode for Dye‐Sensitized Solar Cells

Abstract Metal sulfide stands out as one of the novel and promising platinum‐free counter electrode (CE) materials for dye‐sensitized solar cells (DSSCs). In this work, SnS x ‐SnO 2 ‐decorated CoS x films were designed and synthesized by a low‐temperature fabrication process. The small clusters of nanoparticles create a large amount of catalytic active sites, resulting in superior electrocatalytic activity for triiodide reduction. The DSSC with SnS x ‐SnO 2 ‐decorated CoS x film has achieved an impressive power conversion efficiency of 4.57 %, which is close to the efficiency of the DSSC with platinum CE (4.82 %). Furthermore, regarding the attenuation of the photovoltaic performance for the DSSC with SnS x ‐SnO 2 ‐decorated CoS x film, negligible change was observed after a prolonged storage under ambient condition for five days. Therefore, it is worthwhile to expect the explorations of novel fabricate technique for synthesizing cost‐effective metal sulfide films with long‐term stability in DSSCs.