Sub-nanosecond two-dimensional perovskite scintillators by dielectric engineering.

Perovskite materials have demonstrated great potential for ultrafast scintillators with high light yield. However, the decay time of perovskite still could not be further minimized into sub-nanosecond region, while sub-nanosecond scintillators are highly demanded in various radiation detection, including high-speed X-ray imaging, time-of-flight (TOF) based tomography or particle discrimination, and timing resolution measurement in synchrotron radiation facilities, etc.. Here, we show a rational design strategy to shorten the scintillation decay time by maximizing the dielectric difference between organic amines and Pb-Br octahedral emitters in 2D organic-inorganic hybrid perovskites (OIHP). Benzimidazole (BM) with low dielectric constant inserted between [PbBr 6 ] 2- layers, resulting in a surprisingly large exciton binding energy (360.3±4.8 meV) of 2D OIHP BM 2 PbBr 4 . The emitting decay time is shortened as 0.97 ns, which is smallest among all the perovskite materials. Moreover, the light yield is 3,190 photons/MeV, which is greatly higher than conventional ultrafast scintillator BaF 2 (1,500 photons/MeV). The rare combination of ultrafast decay time and considerable light yield renders BM 2 PbBr 4 excellent performance in γ-ray, neutron, α-particle detection, and the best theoretical coincidence time resolution (CTR) of 65.1 ps, which is only half of the refence sample LYSO (141.3 ps). This article is protected by copyright. All rights reserved.