Organic-inorganic hybrid manganese(II) halides (OIMnHs) have attracted significant interest in optoelectronic fields due to their nontoxicity, special luminescent properties, and structural diversity. However, the OIMnHs have exhibited only green or red emission based on tetrahedral and octahedral crystal field theory, which severely limits further tunability. Here, we synthesized two single crystals (3-DTP)2Mn2Cl8·H2O and 3-DTPMnBr4 3-DTP = 3-(dimethylamino)propyltriphenylphosphonium by halogen replacement from Cl to Br. Moreover, crystal structures, UV-vis diffuse reflectance spectra, theoretical calculations, and photo/radioluminescence of (3-DTP)2Mn2Cl8·H2O and 3-DTPMnBr4 were systematically studied. Especially, photo/radioluminescence results demonstrate that (3-DTP)2Mn2Cl8·H2O and 3-DTPMnBr4 single crystals exhibit yellow/yellow-green emission under UV-365 nm and X-ray irradiations. More importantly, the photoluminescence quantum yield (PLQY) of (3-DTP)2Mn2Cl8·H2O and 3-DTPMnBr4 increased from 4.38% to 18.93%, and their PL lifetime value decreased significantly from 940.7 μs to 99.9 μs with the replacement from Cl to Br. Notably, 3-DTPMnBr4 showed a low X-ray detection limit of 36.8 nGyairs-1 as a potential X-ray scintillator, while (3-DTP)2Mn2Cl8·H2O exhibited the chiral space group P21 (No. 4) with a relatively strong second-harmonic generation effect. This work will provide guidance for constructing novel hybrid metal halide systems compatible with luminescence and second-harmonic generation.
Li et al. (2026) studied this question.