Sb₂Se₃ Thin‐Film Photovoltaics Using Aqueous Solution Sprayed SnO₂ as the Buffer Layer

Sb 2 Se 3 is a promising photovoltaic material due to its suitable bandgap, strong light absorption, simple phase, nontoxicity, and earth‐abundant constituents. Currently, most Sb 2 Se 3 thin‐film solar cells are based on toxic CdS as the buffer layer. Here, for the first time, non‐toxic, wide‐bandgap, and chemically stable SnO 2 is introduced as the buffer layer instead of CdS to build superstrate SnO 2 /Sb 2 Se 3 thin‐film solar cells. The phase of sprayed SnO 2 films and device band alignment are investigated in detail. SnO 2 buffer layer annealed at 480 °C exhibits the lowest interfacial defect density and best device performance. Finally, 3.05% efficiency is achieved and the devices show excellent storage and light‐soaking stability. This preliminary experimental study implies that SnO 2 has potential for developing high‐efficiency, stable, and environmentally friendly Sb 2 Se 3 ‐based solar cells.