Synthesis,structure and optical properties of different dimensional organic–inorganic perovskites

By varying the substituent position of aminomethyl on pyridine ring in acid solution, different dimensional lead bromide frameworks ranging from zero-dimension and one-dimension to two-dimension were obtained. 2-(Aminomethyl)pyridine (2-AMP) or 3-(aminomethyl)pyridine (3-AMP) and PbBr₂ construct hybrid perovskites, of which (H₂2-AMP)PbBr₄ (1) exhibits two-dimensional perovskite sheets with special hydrogen bonds and (H₂3-AMP)₂PbBr₆ (2) shows an uncommon zero-dimensional inorganic framework with isolated octahedra. The characteristic exciton peaks in absorption spectra are located at 431 nm for compound 1 and at 428 nm for compound 2. (H₂4-AMP)PbBr₄ (3) with one-dimensional zigzag edge-sharing octahedral PbBr₄²⁻chains can be obtained using 4-(aminomethyl)pyridine (4-AMP) as organic component under the same experimental conditions as those for 2-AMP and 3-AMP.