Sb2S3/MnS interface optimization for improved all-inorganic Sb2S3 solar cell performance based on NH4F impregnation

Abstract

Sb₂S₃ thin-film solar cells, as an emerging photovoltaic device, have drawn considerable attention due to their large light absorption, abundant raw materials, cost-effectiveness, and environmental sustainability. However, the presence of complex defects, such as vacancy (V_S and V_Sb) and antisite (Sb_S and S_Sb), in Sb₂S₃ thin films and severe interface recombination between the carrier transport layer and the absorber are significant obstacles, which leads to a large discrepancy between the photovoltaic conversion efficiency (PCE) of current solar cells and theoretical predictions. In this study, a facile ammonium fluoride (NH₄F) impregnation process was developed to achieve high-performance Sb₂S₃ solar cells. With the optimal impregnation concentration of 0.07 M and impregnation time of 5 min, this NH₄F impregnation treatment effectively produces high-quality Sb₂S₃ films by reducing surface roughness, improving hydrophilicity, and a preferred [hk1] orientation of Sb₂S₃ films. Furthermore, the Sb₂S₃/MnS heterojunction interface was significantly improved by reducing nonradiative recombination and regulating energy level alignment. The final PCE of the NH₄F-impregnated Sb₂S₃ solar cells reached 6.55 %, representing a 21 % enhancement over untreated devices. This study provides a new approach to optimize the photoelectric conversion performance of Sb₂S₃ photovoltaic devices and simultaneously offers crucial technical support for high-efficiency thin-film solar cells.