[NH(CH)NH]SnX (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)Br and (1,4-BDA)Sn(II)X (where X = Br, I; 1,4-BDA = 1,4-diammoniumbutane) with 0D and 2D structures, respectively.