Achieving Efficient Neutron and Gamma Discrimination in a Highly Stable ⁶Li-Loaded Cs₃Cu₂I₅ Perovskite Scintillator

Low-dimensional Cu(I) perovskite halides with efficient exciton emissions have recently emerged as promising scintillation materials for X-ray and gamma-ray detection applications. Here, we demonstrate the possibility of using zero-dimensional Cs₃Cu₂I₅ for the sensitive detection of thermal neutrons and neutron-gamma discrimination enabled by Li doping. Single crystals of Cs₃Cu₂I₅ doped with 95% enriched ⁶Li were grown by the Bridgman method. Cs₃Cu₂I₅:⁶Li offers a compelling combination of high stability against moisture and oxygen, a decent energy resolution of 4.8% for 662 keV ¹³⁷Cs gamma-rays, a high light yield of 30 000 photons/MeV for gamma-rays, and 96 000 photons/neutron for thermal neutron, and a good neutron-gamma pulse shape discrimination figure of merit of 2.27. Our discovery of ⁶Li-doped low-dimensional perovskite halides opens up a new horizon for stable and high-performance neutron-gamma scintillator design.