Two Organic–Inorganic\nHybrid Manganese Bromides\nwith Highly Efficient Emission toward White LEDs

Organic–inorganic metal halides have attracted\ngreat attention\ndue to their tunable structural and spectroscopic properties. Here,\ntwo organic–inorganic hybrid manganese bromides, (TEMA)<sub>2</sub>MnBr<sub>4</sub> (TEMA = triethylmethylammonium) and (TEBA)<sub>2</sub>MnBr<sub>4</sub> (TEBA = benzyltriethylammonium), are synthesized\nusing the evaporation crystallization method. Following a heat-induced\nphase transition at 363 K, the structure and optical properties of\n(TEMA)<sub>2</sub>MnBr<sub>4</sub> change but return to their initial\nstate upon cooling to room temperature, as confirmed by X-ray diffraction,\nphotoluminescence (PL), and Raman spectra. Meanwhile, (TEBA)<sub>2</sub>MnBr<sub>4</sub>, with a larger Mn–Mn distance, exhibits a\nhigher photoluminescence quantum yield of 98.1% and greater thermal\nquenching temperature. However, due to the poorer thermal stability\nof the organic cation, the crystal melts at 400 K, leading to fluorescence\nquenching. White LEDs based on (TEMA)<sub>2</sub>MnBr<sub>4</sub> and\n(TEBA)<sub>2</sub>MnBr<sub>4</sub> are successfully fabricated with\ncolor rendering indices of 97.4 and 97.2, respectively. The investigation\nprovides deep insights into the structural and optical properties\nof (TEMA)<sub>2</sub>MnBr<sub>4</sub> and (TEBA)<sub>2</sub>MnBr<sub>4</sub>, advancing research for LED display design by tuning organic\ncations.