Exceptional optical performance of the zero-dimensional hybrid cuprous halide ETPA2Cu2I4 as an X-ray scintillator

Abstract

Metal halide materials have demonstrated significant development prospects in the domain of high-energy radiation detection and imaging. When compared to lead-based metal halides, copper-based metal halide materials exhibit advantages such as affordability, environmental compatibility, and outstanding luminescence properties. In this study, we synthesized a zero-dimensional cuprous-based organic–inorganic hybrid metal halide, [C₁₁H₂₆N]₂Cu₂I₄. Through rational asymmetric design of cationic organic quaternary ammonium, this material can achieve cyan self-trapped exciton (STE) emission with a central wavelength of 490 nm. Due to the strong exciton binding and electron–phonon coupling effects, this material manifests a photoluminescence quantum yield (PLQY) close to unity (97.56%) at room temperature, a large Stokes shift (60 606 cm⁻¹), and a short triplet lifetime (2.15 μs). Furthermore, under soft X-ray excitation, the material attains a high light yield of 19 900 photons per MeV, while exhibiting a detection limit as low as 0.524 μGy_air per s. Utilizing this material, flexible large-area X-ray imaging displays with an impressive image resolution of up to 5.47 lp mm⁻¹ were fabricated. Consequently, the results reported here not only unveil the correlation between the high-performance luminescence properties and crystal structure of cuprous-based metal halides but also underscore the promising application prospects of the materials in the field of high-energy radiation detection.