Near-unity broadband luminescent cuprous halide nanoclusters as highly efficient X-ray scintillators

Abstract

X-ray scintillators as functional energy materials possess the powerful ability to convert high-energy radiation into visible light with wide applications in various nuclear radiation fields. In this regard, three-dimensional (3D) lead perovskite nanocrystal-based X-ray scintillators have attracted extensive attention, but their low light yield and serious toxicity extremely restrict their further applications. To address these issues, a family of 0D hybrid cuprous halides of A2Cu4X6 (A = PTPP, TPA; X = Br, I) based on discrete [Cu4X6]2− nanoclusters were demonstrated as highly desirable lead-free scintillators. Upon excitation of both ultraviolet and blue light, these halide nanoclusters displayed that self-trapped excitons induced broadband light emissions from green to red with near-unity photoluminescent quantum yield (PLQY, 93.1%) andlarge Stokes shifts (>1.3 eV). Significantly, the high PLQY, negligible self-absorption, and strong X-ray attenuation from [Cu4X6]2− nanoclusters endowed them with extraordinary radioluminescence properties. The linear radioluminescence intensity response to a wide range of X-ray dose rates gave an acceptable detection limit of 0.7563 µGyair s−1, which was lower than the required value for regular medical diagnostics (5.5 µGyair s−1). X-ray imaging demonstrated an ultrahigh spatial resolution of 14.83 lp mm−1 and negligible afterglow (1.3 ms), showcasing potential applications in X-ray radiography. Overall, the combined superiorities of nontoxicity, high light yield, excellent stability, and good radiation hardness make cuprous halide nanoclusters excellent scintillators.[Figure not available: see fulltext.].