Mn(II)-Activated Zero-Dimensional Zinc(II)-Based Metal Halide Hybrids with Near-Unity Photoluminescence Quantum Yield

As derivatives of metal halide perovskite materials, low-dimensional metal halide materials have become important materials that have attracted much attention in recent years. As one branch, zinc-based metal halides have the potential for practical applications due to their lead-free, low-toxicity and high-stability characteristics. However, pure zinc-based metal halide materials are still limited by their poor optical properties and cannot achieve large-scale practical applications. Therefore, in this work, we report an organic-inorganic hybrid zero-dimensional zinc bromide, (TDMP)ZnBr₄, using transition metal Mn²⁺ ions as dopants and incorporating them into the (TDMP)ZnBr₄ lattice. The original non-emissive (TDMP)ZnBr₄ exhibits bright green emission under the excitation of external UV light after the introduction of Mn²⁺ ions with a PL peak position located at 538 nm and a PLQY of up to 91.2%. Through the characterization of relevant photophysical properties and the results of theoretical calculations, we confirm that this green emission in Mn²⁺:(TDMP)ZnBr₄ originates from the ⁴T₁ → ⁶A₁ optical transition process of Mn²⁺ ions in the lattice structure, and the near-unity PLQY benefits from highly localized electrons generated by the unique zero-dimensional structure of the host material (TDMP)ZnBr₄. This work provides theoretical guidance and reference for expanding the family of zinc-based metal halide materials and improving and controlling their optical properties through ion doping.