Figure 3.

(a) UV–vis absorption spectra of PeABr1, PeABr2, and 3D Cs₂AgBiBr₆ double perovskites measured on thin films at room temperature. (b) Corresponding band structures as obtained from DFT simulations, based on the standard PBE exchange-correlation functional, including SOC. (c) Weighted contributions in the reciprocal space to the lowest energy, dipole-allowed excited state for the investigated compounds, as obtained from an ab initio solution of the Bethe–Salpeter equation.