Constructing density functional tight-binding parameters for electronic structure modeling of lead-bromide...

Density functional tight-binding (DFTB), a semi-empirical approach rooted in density functional theory, is well-suited for simulating large periodic systems. Following Jiang et al. [Phys. Rev. Mater. 9, 023803 (2025)], we have specifically tailored DFTB parameters for accurate electronic bandgap calculations in both three-dimensional and two-dimensional lead bromide perovskites, significantly reducing computational costs compared to conventional ab initio methods. Our electronic DFTB parameters provide reliable predictions for key electronic properties, such as bandgaps and effective masses, closely matching existing experimental data and advanced many body perturbation theory calculations. Furthermore, our approach successfully captures the bandgap trends observed in mixed-halide perovskites, reflecting the variation with halide composition. In addition, we explore the transferability of the newly optimized DFTB parameters to predict the electronic properties of a variety of low-dimensional perovskites and related structures with edge- or face-sharing octahedra.