Pyridine-Modulated Mn Ion Emission Properties of C₁₀H₁₂N₂MnBr₄ and C₅H₆NMnBr₃ Single Crystals

Pb-free inorganic-organic perovskite materials - C₁₀H₁₂N₂MnBr₄ (compound 1) and C₅H₆NMnBr₃ (compound 2) - with different structures were obtained by using pyridine and manganese bromide as raw materials. The single-crystal X-ray diffraction analyses revealed their different lattices in space groups. Compound 1 - Mn tetra-Br-coordinated with two pyridines - presented an isolated mononuclear structure. Its temperature-dependent photoluminescence spectra exhibited an emission band at 523 nm from the lowest d-d crystal field transition of Mn and a higher energy emission at 493 nm from its vibronic state at low temperature. Compound 2 - Mn octahedra-Br-coordinated with a minor pyridine - face-shares with linear chains, which were separated by pyridine molecules. Its emission peak occurred at around 650 nm, in which ferromagnetism was observed. The lifetimes of d-d transition for a single manganese ion and the Mn cluster were presented.