Design of a High-Performance Near-Infrared Scintillator through Metal-Atom Substitution in Metal Chalcogenide

We report the synthesis and optical characterization of a series of metal chalcogenides, A₃SiS₄Te (A = Sr²⁺, Ba²⁺, Eu²⁺), highlighting the metal-atom substitution strategy for the discovery of a high-performance metal chalcogenide-based near-infrared (NIR) scintillator of Eu₃SiS₄Te. Eu₃SiS₄Te exhibits exceptionally broad NIR emission with a full width at half-maximum of 210 nm, the largest among all known Eu²⁺-based NIR emitters. Eu₃SiS₄Te has a high light yield of 41697 photons/MeV and excellent resistance to hygroscopicity. Additionally, Eu₃SiS₄Te boasts a decay time of 531.3 ns, which is merely a quarter of that of the current state-of-the-art NIR scintillators. As a proof of concept, the response to the ²⁴¹Am radioactive source was successfully identified, underscoring its potential for γ-photon-counting applications.