Flexible X-ray luminescence imaging enabled by cerium-sensitized nanoscintillators

Colloidal nanocrystal scintillators hold great potential in fabricating large-area, flexible X-ray detectors for high-resolution X-ray imaging of highly curved, irregularly shaped objects. The synthesis of high-efficiency, high-stability nanoscintillators is of great importance for the development of X-ray imaging detectors. In this study, we develop a class of cerium (Ce3+)-sensitized core-shell nanoscintillators that are suitable for achieving flexible X-ray luminescence imaging. We demonstrate that an epitaxial growth of NaGdF4:Ce(60%) on the surface of NaGdF4:Eu(15%) nanoscintillators as a sensitization layer allows for enhancing X-ray-induced radioluminescence. We reveal that the enhancement of X-ray luminescence in nanoscintillators could be attributed to the synergistic effect of high-Z composition-induced X-ray absorption, Ce3+ sensitization, and surface passivation to relieve energy quenching. By incorporating the nanoscintillators into a flexible elastomer of polydimethylsiloxane (PDMS), we demonstrate its utility in high-resolution flexible X-ray luminescence imaging.