Lattice distortion dependent photoluminescence in two-dimensional hybrid manganese halides by regulating penetration depth of organic amine

Organic−inorganic hybrid Mn-based metal halides display diverse rich optical properties due to their diverse crystal structures and have become one of the most promising candidates in optoelectronic device. However, to the best of our knowledge, the effects of A-site organic cation permeation on the crystal structure and photoluminescence properties of hybrid metal halides have not been reported. Herein, two similar organic aromatic amines, i.e., aniline (PA) and phenylethylamine (PEA) as A-sites were used to prepare single layer two-dimensional (2D) Ruddlesden−Popper phase PA2MnCl4 and PEA2MnCl4 metal halides, respectively. The effects of penetrating depth of organic amine on the luminescence properties are investigated using these two crystals with consistent crystal structures but inconsistent organic amine with molecular configuration as a comparable model. The tail NH3 of PA2MnCl4 is penetrated deeper into the inorganic layer than that of PEA2MnCl4 and increases [MnCl6]4- octahedral distortion and the octahedral local crystallographic field, resulting in different distortion degree of inorganic octahedra, electronic energy levels, optical properties of two compounds. Our study provides new insights for designing and modulating the luminescent properties of 2D organic−inorganic hybrid metal halides.