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

Sb2Se3 is a promising photovoltaic material due to its suitable bandgap, strong light absorption, simple phase, nontoxicity, and earth‐abundant constituents. Currently, most Sb2Se3 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 SnO2 is introduced as the buffer layer instead of CdS to build superstrate SnO2/Sb2Se3 thin‐film solar cells. The phase of sprayed SnO2 films and device band alignment are investigated in detail. SnO2 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 SnO2 has potential for developing high‐efficiency, stable, and environmentally friendly Sb2Se3‐based solar cells.