Organic Chloride Salt Interfacial Modified Crystallization for Efficient Antimony Selenosulfide Solar Cells

Antimony selenosulfide, Sb₂(SSe)₃, is recognized as an excellent photoactive material owing to its light harvesting capability. There is still room for improvement of the film quality for device performance improvement. Herein, an organic chloride salt [diethylamine hydrochloride, DEA(Cl)] has been introduced for fabricating Sb₂(SSe)₃ solar cells for the first time. A champion device with a power conversion efficiency (PCE) of 9.17% has been achieved with a relatively improved fill factor and open-circuit voltage (V_OC). It has been revealed that DEA(Cl) successfully interacts with Sb₂(SSe)₃, which can facilitate the crystallization process to give rise to the closely packed bigger grain sizes with reduced surface cracks; it successfully suppressed the oxidized Sb species (Sb₂O₃) in the Sb₂(SSe)₃ film to give rise to phase purity, thus leading to superior surface morphology and electrical characteristics of DEA(Cl)-modified Sb₂(SSe)₃ absorber films. Chloride modification is thus efficiently helpful in suppressing interfacial defects, improving junction quality, and optimizing energy-level alignment. This facile interfacial modification demonstrates the remarkable potential for efficient Sb₂(SSe)₃ solar cells.