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.

CuSbSe₂ is a promising absorber material for thin film solar cells because of its chemistry similarity to the well-known CuInSe₂ but with low-cost and earth abundant component. Various methods have been employed to fabricate CuSbSe₂ thin films with the best photovoltaic device achieving nearly 5% efficiency. Here, we develop a reactive close-spaced sublimation method to prepare high quality CuSbSe₂ films via one evaporation process. In this method, a Cu layer is pre-sputtered onto the substrate, then reacts with Sb₂Se₃ vapor and its decomposition product Se, and finally generates single-phased CuSbSe₂ films with large grains and proper doping density. This new strategy not only suppresses the decomposition of ternary chalcogenide CuSbSe₂ but also is simple and applicable to other ternary semiconductors. Finally, based on this method, we have built prototype solar cells with a structure of AZO/CuSbSe₂/CdS/i-ZnO/ZnO:Al/Au and obtained 3.04% power conversion efficiency for the champion device.