0D Organic Manganese(II) Bromide Hybrids as Stable and Efficient X‐Ray Scintillator

Low‐dimensional organic–inorganic hybrids have emerged as promising X‐ray scintillators due to efficient radioluminescence properties. Herein, stable and efficient X‐ray scintillator based on 0D (C 40 H 38 P 2 )MnBr 4 hybrid single crystals grown by a facile solution‐processing method is reported. Its crystal structure is determined to be triclinic with P space group. It has good stability against moisture and irradiation. (C 40 H 38 P 2 )MnBr 4 with tetrahedrally coordinated Mn 2+ exhibits green emission peaking at 518 nm originating from d–d 4 T 1 → 6 A 1 transition of Mn 2+ ion with a high photoluminescence quantum yield (PLQY) of 74.2%. Under X‐ray excitation, it shows high scintillation yield of 32 000 photons MeV −1 , a decent detection limit of 288 nGy air s −1 , and a low afterglow comparable to that of Bi 4 Ge 3 O 12 (BGO).