Structure-Composition-Property Relationships in Antiperovskite Nitrides: Guiding a Rational Alloy Design

The alloy strategy through the A- or X-site is a common method for experimental preparation of high-performance and stable lead-based perovskite solar cells. As one of the important candidates for lead-free and stable photovoltaic absorbers, the inorganic antiperovskite family has recently been reported to exhibit excellent optoelectronic properties. However, the current reports on the design of antiperovskite alloys are rare. In this work, we investigated the previously overlooked electronic property (e.g., conduction band convergence), static dielectric constant, and exciton binding energy in inorganic antiperovskite nitrides by first-principles calculations. Then, we revealed a linear relationship between the tolerance factor and various physical quantities. Guided by the established structure-composition-property relationship in six antiperovskite nitrides X₃NA (X²⁺ = Mg²⁺, Ca²⁺, Sr²⁺; A^3- = P^3-, As^3-, Sb^3-, Bi^3-), for the first time, we designed a promising antiperovskite alloy Mg₃NAs_0.5Bi_0.5 with a quasi-direct band gap of 1.402 eV. Finally, we made a comprehensive comparison between antiperovskite nitrides and conventional halide perovskites for pointing out the future direction for device applications.