Cs3Cu2I5 Nanocrystals with Near-Unity Photoluminescence Quantum Yield for Stable and High-Spatial-Resolution X-ray Imaging

Abstract

With almost negligible self-absorption and high photoluminescence quantum yield (PLQY), zero-electronic-dimensional Cs3Cu2I5 emerges as an excellent scintillator. Ball-milling is a desired method to prepare Cs3Cu2I5 scintillators at a large scale; however, the defects generated during ball-milling and large particle size hinder its scintillation properties. Theoretical analysis suggests that utilizing a molecule with a small surface energy and a passivation group during ball-milling could be a two-birds-with-one-stone strategy, which can simultaneously improve the PLQY of particles by defect passivation and decrease the particle size by minimizing the surface energy of particles and inhibiting particle rewelding. Accordingly, we successfully prepared Cs3Cu2I5 nanoparticles with a near-unity PLQY and smaller size using a passivator (nonaethylene glycol monododecyl ether, C12E9)-assisted ball-milling method. The interaction of C12E9 with Cs3Cu2I5 has been verified and could enhance the luminescence performance of Cs3Cu2I5. Further, the Cs3Cu2I5 nanoparticle coating delivered a spatial resolution of 17.5 lp mm–1@MTF = 0.2 in X-ray imaging and excellent stability under prolonged X-ray irradiation with total dose of 10.9 Gyair, equal to the dose of 108,000 medical chest X-ray inspections. These results suggest that this in situ passivator-assisted ball-milling method is effective for large-scale production of high-quality Cs3Cu2I5 nanoparticles with excellent scintillation performance.