Manganese-Based Halogen Regulation Enhances Photoluminescence Efficiency Engineering

Organic–inorganic hybrid halides flourish due to their thermal stability, plasticity, and optical properties. However, performance optimization through reasonable regulation has always been a challenge. Diverse anions offer a broad range of possibilities and options for the development of stimulus-responsive materials, thereby facilitating performance optimization. Here, we have successfully synthesized two organic–inorganic photoluminescent hybrid halides, (NNDP)2MnX4 (NNDP = N,N-dimethylpiperidinium chloride; X = Cl, Br), with a significant enhancement in photoluminescence quantum yield (4.38% → 39.91%) via halogen modulation. The increase in quantum yield is attributed to the distortion in the [MnX4]2– tetrahedron. Furthermore, the phase-transition temperatures of (NNDP)2MnCl4 and (NNDP)2MnBr4 were determined as 347 and 335 K, respectively, through thermodynamic measurement. Meanwhile, the intermolecular forces of (NNDP)2MnCl4 and (NNDP)2MnBr4 were analyzed using a Hirshfeld surface and a two-dimensional (2D) fingerprint. This study injects new innovative ideas for the design of novel photoluminescent materials.