Eco‐Friendly and Highly Efficient Light‐Emission Ferroelectric Scintillators by Precise Molecular Design

Hybrid manganese halide has attracted much attention in the field of environment friendly ferroelectric and photo‐responsive multifunctional materials. Here, the highly efficient photoluminescent inorganic framework MnBr 4 2− is utilized to conceive and synthesize a series of hybrid manganese bromide compounds [RQ] 2 MnBr 4 by introducing precisely designed quasi‐spherical cations [RQ] + (R = H, Me, Et, FEt, Q = quinuclidine). The accurate and effective modification of cations not only achieves the satisfactory ferroelectricity, but also enhances the photoluminescence quantum yield from 38.7% to 83.65%. Moreover, [FEtQ] 2 MnBr 4 shows a highly efficient X‐ray scintillator performance, including a large range of linear response to X‐ray dose rate from 0.3 to 414.2 μ Gy air s −1 , a high light yield of 34 438 photons per MeV, and a low detection limit of 258 nGy air s −1 . This work provides an efficient strategy for the preparation of hybrid manganese halide ferroelectrics with highly efficient light‐emission and X‐ray detection.