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 degrees 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.