Over 10% Efficient Sb(S,Se) Solar Cells Enabled by CsI-Doping Strategy.

Antimony selenosulfide (Sb(S,Se)) is an emerging quasi-1D photovoltaic semiconductor with exceptional photoelectric properties. The low-symmetry chain structure contains complex defects and makes it difficult to improve electrical properties via doping method. This article reports a doping strategy to enhance the efficiency of Sb(S,Se) solar cells by using alkali halide (CsI) as the hydrothermal reaction precursor. It is found that the Cs and I ions are effectively doped and atomically coordinate with Sb ions and S/Se ions. The CsI-doping Sb(S,Se) absorbers exhibit enhanced grain morphologies and reduced trap densities. The consequential CsI-doping Sb(S,Se) based solar cells demonstrate favorable band alignment, suppressed carrier recombination, and improved device performance. An efficiency as high as 10.05% under standard AM1.5 illumination irradiance is achieved. This precursor-based alkali halide doping strategy provides a useful guidance for high-efficiency antimony selenosulfide solar cells.