Controlled Modulation of the Structure and Luminescence Properties of Zero-Dimensional Manganese Halide Hybrids through Structure-Directing Metal-Ion (Cd 2+ and Zn 2+ ) Centers.

Zero-dimensional (0D) metal halide hybrids with high exciton binding energy are excellent materials for lighting applications. Controlling/modulating the structure of the constituent metal halide units allows tunability of their photoluminescence properties. 0D manganese halide hybrids are currently attracting research efforts in lighting applications due to their eco-friendly and strong emission. However, structural transformation-induced tunability of their photophysical properties has rarely been reported. Herein, we demonstrate a rational synthetic strategy to modulate the structure and luminescence properties of 0D Mn(II) halide hybrids utilizing the structure-directing d 10 metal ions (Cd 2+ /Zn 2+ ). 0D metal halide hybrids of Cd 2+ /Zn 2+ , which act as hosts with tunable structures, accept Mn 2+ ions as substitutional dopants. This structural flexibility of the host d 10 metal ions is realized by optimizing the metal-to-ligand ratio (Cd/AEPip). This reaction parameter allows structural transformation from an octahedral (AEPipCdMnBrO h ) to a tetrahedral (AEPipCdMnBrT d ) 0D Mn halide hybrid with tunable luminescence (orange → green) with high photoluminescence quantum yield. Interestingly, when Zn 2+ is utilized, a tetrahedral AEPipZnMnBr structure forms exclusively with strong green emission. Optical and single-crystal X-ray diffraction structural analysis of the host and the doped system supports our experimental data and confirms the structure-directing role played by Cd 2+ /Zn 2+ centers. This work demonstrates a rational strategy to modulate the structure/luminescence properties of 0D Mn(II) halide hybrids, which can further be implemented for other 0D metal halide hybrids.