Temperature‐ and Pressure‐Dependent Emissions and Crystal‐ Glass Transition of a Hybrid Manganese Bromide†

Comprehensive Summary Herein, the temperature‐ and pressure‐stimulated responsive behavior as well as crystal‐glass phase transition of a new zero‐dimensional hybrid manganese bromide [4‐MTPP] 2 [MnBr 4 ] [4‐MTPP + = (4‐methoxybenzyl)tris(phenyl)phosphonium)] were reported. Our experiment results demonstrate that [4‐MTPP] 2 [MnBr 4 ] shows typical green photoluminescence emission centered at 522.4 nm excited by UV light, with a high photoluminescence quantum yields value of 79.36% and a large lifetime of 368.6 μs, attributing to its direct bandgap electronic structure. Further, the photoluminescence emission of [4‐MTPP] 2 [MnBr 4 ] presents a monotonically blue shift with the increased temperature, originating from the decreased crystal field strength where the Mn 2+ stays owing to lattice thermal expansion effect. On the contrary, as the pressure increases, the photoluminescence emission of [4‐MTPP] 2 [MnBr 4 ] exhibits a progressive red shift, which can be attributed to the increased crystal field strength of Mn 2+ due to the effect of pressure‐induced lattice shrinkage. Meanwhile, its quenched emission can be successfully restored when the pressure returns to the ambient pressure. In addition, [4‐MTPP] 2 [MnBr 4 ] crystals show a crystal‐glass phase transition at the temperature of 74 °C. Intriguingly, the melt‐quenched glass of [4‐MTPP] 2 [MnBr 4 ] exhibits green emission under UV light excitation with a large lifetime of 302.2 μs.