[MnCl3(H2O)3]- to [MnCl6]4-: The effect of inorganic polyhedron transformation on luminescence characteristics

Organic-inorganic hybrid halides (OIHs) have attracted widespread attention because of their exceptional optoelectronic properties. In particular, Mn2+-based hybrid halides show intense green or red emission, which benefit from distinct d-d optical transition in Mn2+. This work deals with the dual-emission in two novel hybrid single-crystals (N-AEP)[MnCl3(H2O)3]2·Cl (1) and [(N-AEP)2MnCl6]·2Cl (2) (N-AEP3+ = C6H18N33+). Luminescence properties studies indicate that the low-energy emission is assigned to the Mn2+-based octahedron, while the high-energy emission ascribes to the organic cation [N-AEP]3+. Inorganic polyhedron transformation ([MnCl3(H2O)3]- to [MnCl6]4-) increased the luminescent intensity, which benefited from the weaker nonradiative transition in [MnCl6]4- octahedron. Significantly, by finely adjusting the excitation wavelength, complex 2 showed tunable emission properties, realizing the transition from “warm” white light (0.40, 0.33) to “cold” white light (0.28, 0.28). This paper offers a new example on the effective design of dual-emission materials.