Hopscotching perovskites: DFT leveraged tight-binding insights into inorganic lead halide perovskites.

Delocalization insights into inorganic lead halide perovskites of the form CsPbBrI ( = 0, 1, 2, 3), obtained a DFT based tight-binding method, are presented. Compared to first principles studies like DFT (physically accurate and computationally expensive), the tight-binding approach allows the disentanglement of the region of interest, namely, the Fermi level. Further adjustment of the hopping norm and maximum distance leads to a simplified, highly interpretable but chemically grounded, reduced model which regenerates the broad features of the band structure with a fraction of the parameters.