Fig. 3.

a Tauc plot (assumed indirect bandgap), b-c calculated band structure of (MA)₂KBiCl₆ and the enlarged view of the band structure near the bandgap. Reproduced with permission from Ref. [38]. d Tauc plot (assumed direct bandgap) of (MA)₂TlBiBr₆. Reproduced with permission from Ref. [82]. e XRD patterns of fresh (MA)₂AgSbI₆ compared to (MA)₂AgSbI₆ after 370 days of exposure to air. Reproduced with permission from Ref. [84]. f Air stability of (MA)₂AgBiI₆. Reproduced with permission from Ref. [85]. g Schematic illustration of rhombohedral-to-cubic phase transition on high-temperature heating for (MA)₂KGdCl₆ and (MA)₂KYCl₆. Reproduced with permission from Ref [86]. h Photograph of a (MA)₂AgBiBr₆ single crystal. Reproduced with permission from Ref. [87]