Surface passivation of Cs₂AgI₃:Cu with AgI for high-performance X-ray imaging scintillators

Abstract

High-performance X-ray scintillators are essential for advanced imaging technologies in various fields, including security, aerospace, high-energy physics, and health care. However, the existing scintillation materials in the X-ray community face significant challenges related to low light yield, long decay time, afterglow, and toxicity. This study reports a novel post-synthesis surface engineering strategy for copper (Cu)-doped dicesium silver iodide (Cs₂AgI₃) using a precisely controlled silver iodide (AgI) treatment to address surface defects, significantly enhancing radiative channels. Density functional theory calculations indicate that AgI treatment passivates the surface defects introduced by Cu⁺ doping, substantially reducing nonradiative recombination centers. Thus, the proposed scintillator achieves an exceptional light yield of over 55 000 photons MeV⁻¹ and a rapid response time of ≈426.4 ns, significantly outperforming the existing commercial scintillators. Furthermore, the scintillator film exhibits an impressive X-ray imaging resolution (18.5 lp mm⁻¹), enhanced durability, and easy processing, facilitating the scalable production of flexible scintillation screens. These significant advancements underscore the potential of the surface engineering strategy for next-generation scintillation materials in X‑ray imaging technology.