Figure 2.

UV–vis spectra of MA₃Sb₂I₉ (A) and Cs₃Sb₂I₉ (B). Reprinted with permission from ref (13). Copyright 2018 American Chemical Society. UV–vis spectra of Cs₃Sb₂I₉, Rb₃Sb₂I₉, and K₃Sb₂I₉ perovskite materials (C). Reprinted with permission from ref (14). Copyright 2017 Royal Society of Chemistry.