Strong Dopant-Dopant Electronic Coupling in Emissive Codoped Two Dimensional Metal Halide Hybrid.

Multimetallic halide hybrids are attractive for the fundamental understanding of interacting excitons. However, realizing halide hybrids that incorporate multiple heterometal centers has been synthetically challenging. This further limits access to gaining physical insight into the electronic coupling mechanism between the constituent metal halide units. Reported herein is an emissive heterometallic halide hybrid, synthesized by codoping (with Mn2+, Sb3+) a 2D host (C6H22N4CdCl6) hybrid, that shows strong dopant-dopant interaction. Here, C6H22N4Sb0.003Mn0.128Cd0.868Cl6 codoped hybrid shows weak green emission (Sb3+ dopant based) and strong orange emission (Mn2+ dopant based). The observed dominance of the Mn2+ dopant emission, arising due to efficient energy transfer between the distant dopants (Sb3+ → Mn2+), highlights strong dopant-dopant electronic coupling. DFT calculations, supporting the observed dopant-dopant interaction, suggest that the electronic coupling between the dopant units (Mn-Cl; Sb-Cl) is mediated by the 2D networked host structure. This work reports physical insight into the coupling mechanism of interacting excitons in multimetallic halide hybrids synthesized through a codoping strategy.

Controlled Modulation of the Structure and Luminescence Properties of Zero-Dimensional Manganese Halide Hybrids through Structure-Directing Metal-Ion (Cd2+ and Zn2+) 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 d10 metal ions (Cd2+/Zn2+). 0D metal halide hybrids of Cd2+/Zn2+, which act as hosts with tunable structures, accept Mn2+ ions as substitutional dopants. This structural flexibility of the host d10 metal ions is realized by optimizing the metal-to-ligand ratio (Cd/AEPip). This reaction parameter allows structural transformation from an octahedral (AEPipCdMnBrOh) to a tetrahedral (AEPipCdMnBrTd) 0D Mn halide hybrid with tunable luminescence (orange → green) with high photoluminescence quantum yield. Interestingly, when Zn2+ 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 Cd2+/Zn2+ 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.