Figure 5.

Electronic band structure of THPs. a) Electronic structure of Sn and Pb atoms. b) Schematics of s state valence electrons in SnI₂ and PbI₂. c) Energy band schematics of MASnI₃ and MAPbI₃. d) GW + SOC calculated band structure of MASnI₃. e) GW + SOC calculated electronic DOSs and optical absorption spectra (inset) of MASnI₃ and MAPbI₃. d,e) Adapted with permission.^{[ 48 ]} Copyright 2014, Nature Publishing Group. f) Optical bandgaps of THPs and LHPs FA_{1‐ x} Cs _x SnI₃ (0 ≤ x ≤ 1) as a function of Cs content. g) Perovskite lattice diagrams (top row) and corresponding energy level diagrams (bottom row) of lattice contraction (left panel), normal lattice (center panel), and octahedral tilting (right panel). f,g) Reproduced with permission.^{[ 66 ]} Copyright 2017, American Chemical Society.