Ag Management of Rudorffites Solar Cells Utilizing Aliphatic Ammonium

As environmentally friendly compounds, lead-free perovskites have gained widespread application in the fabrication of solar cells in recent years. Among these, rudorffites such as AgBiI4 are considered as promising candidates owing to their favorable band structure and exceptional stability. However, the formation of Ag vacancies during the synthetic process poses a significant challenge, severely hindering carrier transport properties. To address this issue, we propose an Ag management (AM) strategy utilizing aliphatic ammonium, which serves multiple purposes: it enhances the solubility of AgI in the precursor solution, mitigates phase separation caused by stoichiometric mismatches during AgBiI4 film formation, and effectively passivates Ag defects. The butylamine hydroiodide (BAI) modified AgBiI4 solar cells achieved a champion power conversion efficiency of 1.97%, representing a 26% enhancement over the control device.