[NH3(CH2)4NH3]SnX4 (X = Br, I): Dion–Jacobson type 2-D perovskites with short interlayer spacing.

Two-dimensional tin(II) halide perovskites stand as an environmentally benign alternative to Pb(II) halide perovskites. However, they are often challenging to make due to the oxidation of Sn(II) ion to more stable Sn(IV) ion. Here we report hybrid tin bromide and iodide perovskites: (1,4-BDA)Sn(IV)Br₆ and (1,4-BDA)Sn(II)X₄ (where X = Br, I; 1,4-BDA = 1,4-diammoniumbutane) with 0D and 2D structures, respectively. Their synthesis, structural characterization and photophysical properties are reported. They show bandgaps in the 1.94–2.70 eV range. [ABSTRACT FROM AUTHOR]