RESUMO
The expanding applications of X-ray scintillation across various areas, from healthcare to security detection call for the development of new-generation scintillators that offer enhanced sensitivity, efficiency, and versatility. Here, we report for the first time the use of organic metal halide complexes with aggregation-induced emission (AIE) for X-ray scintillation, which can be facilely synthesized and processed in the solution phase. By reacting an AIE organic molecule, 4-(4-(diphenylamino) phenyl)-1-(propyl)-pyridinium (TPA-PD) with zinc chloride (ZnCl2) in solution at room temperature, an organic metal halide complex, (TPA-PD)2ZnCl2, is produced with a high synthetic yield of 87%. Optical and radioluminescence characterizations find that (TPA-PD)2ZnCl2 exhibits bluish-green photoluminescence and radioluminescence peaked at around 450 nm, with a photoluminescence quantum efficiency (PLQE) of 65%, and an absolute light yield of 13 423 Photon per MeV. Moreover, short photoluminescence and radioluminescence decay lifetimes are recorded at 1.81 ns and 5.24 ns, respectively. For X-ray scintillation, an excellent response dose-response linearity and a low limit of detection of 80.23 nGyair S-1 are obtained for (TPA-PD)2ZnCl2. By taking advantage of the high X-ray absorption of metal halides and fast radioluminescence of AIE molecules, our design of covalently bonded organic metal halide complexes opens up new opportunities for the development of high-performance solution-processable scintillators.
RESUMO
Scintillators, one of the essential components in medical imaging and security checking devices, rely heavily on rare-earth-containing inorganic materials. Here, a new type of organic-inorganic hybrid scintillators containing earth abundant elements that can be prepared via low-temperature processes is reported. With room temperature co-crystallization of an aggregation-induced emission (AIE) organic halide, 4-(4-(diphenylamino) phenyl)-1-(propyl)-pyrindin-1ium bromide (TPA-PBr), and a metal halide, zinc bromide (ZnBr2 ), a zero-dimensional (0D) organic metal halide hybrid (TPA-P)2 ZnBr4 with a yellowish-green emission peaked at 550 nm has been developed. In this hybrid material, dramatically enhanced X-ray scintillation of TPA-P+ is achieved via the sensitization by ZnBr4 2- . The absolute light yield (14,700 ± 800 Photons/MeV) of (TPA-P)2 ZnBr4 is found to be higher than that of anthracene (≈13,500 Photons/MeV), a well-known organic scintillator, while its X-ray absorption is comparable to those of inorganic scintillators. With TPA-P+ as an emitting center, short photoluminescence and radioluminescence decay lifetimes of 3.56 and 9.96 ns have been achieved. Taking the advantages of high X-ray absorption of metal halides and efficient radioluminescence with short decay lifetimes of organic cations, the material design paves a new pathway to address the issues of low X-ray absorption of organic scintillators and long decay lifetimes of inorganic scintillators simultaneously.
