Self-assembled colloidal glass with 100% lanthanide nanocrystal loading for high-resolution X-ray imaging

Abstract

Solution-processable colloidal scintillators are emerging as a promising alternative to traditional bulky scintillators, addressing critical limitations in X-ray imaging technologies. Existing X-ray screens fabricated with colloidal powders in polymer matrices suffer from low spatial resolution at elevated particle concentrations due to severe optical losses induced by nanoparticle aggregation, fundamentally constraining high-resolution imaging capabilities. To resolve these challenges, we developed a novel class of bright, transparent colloidal glasses achieving 100% particle loading through self-assembly of sub-5 nm lanthanide-doped CaMoO₄ nanocrystals. By modulating solvent surface tension and volatility during the evaporation process, we successfully produced crack-free, densely packed transparent colloidal scintillator films. The self-assembled colloidal glass demonstrates an impressive 80% photoluminescence quantum yield and >80% transparency across the visible spectrum. Moreover, the developed screen exhibits remarkable sensitivity, detecting radiation doses as low as 186 nGy s⁻¹ with an outstanding X-ray imaging resolution of 27.1-line pairs per millimeter, outperforming most conventional organic and inorganic scintillators. These findings illuminate a compelling pathway for utilizing nanomaterials to replace traditional single-crystal scintillators in high-resolution X-ray imaging, potentially revolutionizing medical imaging and radiation detection technologies.