Hot Exciton‐Based Plastic Scintillator Engineered for Efficient Fast Neutron Detection and Imaging

Abstract Scintillators play a crucial role in the fields of radiation detection and imaging, but it is a formidable challenge to meet the demands for large size, high light yield, and fast response simultaneously. To tackle this challenge, this work interprets the key role of the polymer matrix in customizing the overall performance of the organic scintillator from the underlying logic. Owing to this, plastic scintillators Tetra(p‐bromophenyl)ethene@Poly(vinyltoluene) (TPE‐4Br@PVT), are successfully prepared using an amorphous conjugated polymer matrix PVT and an in situ polymerization process. This scintillator features an ultra‐large size (≈191 cm 3 ), ultrafast decay time (1.66/5.26 ns), and decent light yield (14 443 photons·MeV −1 ). It not only achieves a high X‐ray imaging resolution of 13.9 lp·mm− 1 (lp: line pairs) but also a record‐breaking fast neutron imaging resolution of 2.03 lp·mm− 1 , showcasing great potential in radiation detection and imaging applications.