Prediction and Synthesis of a Selenide Perovskite for Optoelectronics

The advent of halide perovskites in recent years has opened an avenue for redeveloping perovskite materials as semiconductors. In the quest for semiconducting perovskites, chalcogenides, which exhibit higher stability than their halide siblings and often direct band gaps for optoelectronics, have attracted more and more attention. So far, functional chalcogenide perovskites have been exclusively sulfides. Here, employing first-principles calculations and the criterion of phase stability in addition to the commonly used thermodynamic and dynamical criteria, we precisely predict the existence of LaScSe₃ as a thermodynamically stable selenide perovskite, which is validated by our experimental synthesis. Combining hybrid functional and many-body quasi-particle (G₀W₀ and Bethe-Salpeter equation) calculations, we predict that LaScSe₃ is a direct-gap semiconductor having the band gap in the green-to-blue region and capable of p- and n-type bipolar doping, potentially for optoelectronic applications.