Anion‐Swapped Antiperovskite X 3 AB: Stability Evaluation and Photovoltaic Potential From First‐Principles Study

We report a comprehensive high‐throughput first‐principles investigation of novel anion‐swapped antiperovskite compounds X 3 AB ( X = alkali metals, Cu, and Ag; A = halogens; B = chalcogens) with a Pnma prototype, derived from the well‐known antiperovskite X 3 BA structures by exchanging anion positions. We systematically evaluated their crystallographic, thermodynamic, and dynamical stability, followed by optoelectronic property predictions and photovoltaic performance evaluation. Among the 112 proposed structures, 19 stable candidate compounds are selected as both thermodynamic and dynamical stable. Moreover, two candidates, Rb 3 FO and Cs 3 BrSe, were identified as possessing promising electronic and optical characteristics, including proper bandgaps, benign transitions probabilities and carrier properties for solar cell applications. Their photovoltaic performance are explicitly evaluated by calculating the spectroscopic limited maximum efficiency (SLME) with consideration of both absorption spectra and film thickness aspects. Our analysis reveals distinctive stability and band structure trends induced by anion inversion, highlighting their potential in optoelectronics applications.