On the possibility of hybrid chalcogenide perovskite photovoltaics

Chalcogenide perovskites are an emerging class of photovoltaic absorbers offering stable, lead-free structures and promising optoelectronic properties. To date, the literature on chalcogenide perovskites has focused primarily on fully inorganic systems such as BaZrS₃. This contrasts with the halide perovskites, for which hybrid organic-inorganic systems exhibit record performance. In this work, we assess the viability of hybrid chalcogenide perovskite absorbers using first-principles calculations. We screen a wide range of monovalent and divalent organic cations within the A-site to evaluate their electronic, optical, and thermodynamic properties. Our analysis reveals that the majority of candidates are structurally unstable; however, we identify the hydrazinium cation (N₂H₆²⁺) as a unique candidate that maintains a stable perovskite structure. Specifically, we identify N₂H₆ZrSe₃ as the most promising candidate, exhibiting a quasi-direct band gap of 1.31 eV and a theoretical maximum efficiency of 24.5% for a 200-nm thin film. This study represents the first comprehensive computational report on hybrid chalcogenide perovskites, opening new avenues for the development of Earth-abundant photovoltaic materials.