Theoretical Investigation of the Electronic Property Trends of Antiperovskites with A-site Tetrahedral Cluster Anion

Antiperovskites have garnered significant research interest due to their structural similarity to traditional perovskites and their potential in optoelectronic applications. Recently, their derivatives featuring a combination of tetrahedral and octahedral units within a single antiperovskite lattice have been experimentally synthesized. However, the compositional space of such structural motifs suitable for photovoltaic applications remains largely unexplored. In this study, we perform high-throughput first-principles calculations to screen a series of novel antiperovskite compounds with the general formula X₃BA, where the A-site anions are replaced with tetrahedral anion clusters such as (CuCl₄)³⁻, (ZnH₃O)³⁻ and (SiO₃Cl)³⁻. Specifically, we evaluate the formability of 60 X₃BA compounds, each considered in four competing crystal phases (I4/mcm, P4ncc, Pca2₁, and Pnma), and systematically analyze the influence of crystal symmetry, tetrahedral cluster anions, and octahedral factors on their electronic structures. Considering geometric factors and electronic band gap criteria, six thermodynamically stable compounds in the I4/mcm phase are identified from 240 candidate structures, including Ca₃PCuCl₄, Ca₃AsCuCl₄, Sr₃PCuCl₄, Sr₃AsCuCl₄, Ba₃PCuCl₄, and Ba₃AsCuCl₄. Among them, Ba₃AsCuCl₄ stands out as a promising photovoltaic absorber, featuring an optimal HSE06 band gap of 1.55 eV, appropriate carrier effective masses, and strong parity-allowed transitions between band edges at the Γ point. This work expands the structural design paradigm of inorganic solar cell absorbers by simultaneously integrating the core structural motifs of perovskite photovoltaic materials, offering new insights into the development of next-generation photovoltaic absorbers.