Synergy of Organic and Inorganic Sites in 2D Perovskite for Fast Neutron and X‐Ray Imaging

Abstract Fast neutron and X‐ray imaging are considered complementary nondestructive detection technologies. However, due to their opposite cross‐sections, development of a scintillator that is sensitive to both fast neutrons and X‐rays within a single‐material framework remains challenging. Herein, an organic–inorganic hybrid perovskite (C 4 H 9 NH 3 ) 2 PbBr 4 (BPB) is demonstrated as a scintillator that fully meets the requirements for both fast neutron and X‐ray detection. The hydrogen‐rich organic component acts as a fast neutron converter and produces detectable recoil protons. The heavy atom‐rich inorganic fraction efficiently deposits the energy of charged recoil protons and directly provides a large X‐ray cross‐section. Due to the synergy of these organic and inorganic components, the BPB scintillator exhibits high light yields (86% of the brightness of a commercial ZnS (Ag)/ 6 LiF scintillator for fast neutrons; 22 000 photons per MeV for X‐rays) and fast response times ( τ deca y = 10.3 ns). More importantly, energy‐selective fast neutron and X‐ray imaging are also demonstrated, with high resolutions of ≈1 lp mm −1 for fast neutrons and 17.3 lp mm −1 for X‐rays; these are among the highest resolution levels for 2D perovskite scintillators. This study highlights the potential of 2D perovskite materials for use in combined fast neutron and X‐ray imaging applications.