Boosting Photovoltaic Respond Through Molecular Engineering in Organic Manganese (II) Bromide for High-Sensitivity X‑Ray Detection.

Zero-dimensinoal (0D) manganese-based metal halides (MHs) demonstrate excellent structural tunable through organic cation design, enabling precise control of Mn─Mn distances to modulate critical photoelectric physical properties. Here, two novel 0D PTAMnBr (PTA = phenyltrimethylammonium) are synthesized and DMAMnBr (DMA = dimethylammonium) wafer with a manipulation of octahedra are synthesized by a precise molecular design. Structural analysis reveals that the PTA-functional group with extended π-conjugation lengths increases the Mn─Mn distance, results in a lower energy transfer and reduced exciton binding energy compared to DMA⁺ (linear carbon chain). Consequently, PTAMnBr demonstrates an enhanced photoluminescence quantum yield and prolonged exciton lifetime. The engineered X-ray detector based on PTAMnBr wafer exhibits a higher sensitivity of 1122 µC Gy cm and a lower detection limit of 95 nGy s, while DMAMnBr device are 708.2 µC Gy cm and 180 nGy s, respectively, which paves the way for high-efficiency photoelectronic applications. This suggests that molecular engineering is a robust approach for designing high-performance 0D manganese halides for radiation detection.