Afterglow-Suppressed LuO:Eu Nanoscintillators for High-Resolution and Dynamic Digital Radiographic Imaging.

LuEuO nanoscintillators ( = 0.005, 0.01, 0.03, 0.05, 0.07, and 0.10) with red emission were synthesized by a coprecipitation method. It is found that their photo- and radioluminescence intensities increase with increasing Eu concentration until = 0.05. According to their concentration-dependent luminescence intensity ratios ((C)/(S)), the existing energy transfer from Eu(S) (occupying S sites) to Eu(C) (occupying C sites) can be confirmed. Based on the spectral data and density functional theory (DFT) calculations, the origin of LuO:Eu persistent luminescence at low concentration might be related to the tunneling processes between Eu (occupying C and S sites) and oxygen interstitials (O). After dispersing afterglow-suppressed LuO:Eu nanoscintillators into polymethyl methacrylate (PMMA) polymer-acetone solution, flexible PMMA-LuO:Eu composite films with high thermal stability and radiation resistance were fabricated by a doctor blade method. As the flexible composite film was used as an imaging plate, static X-ray images with high spatial resolution (5.5 lp/mm) under an extremely low dose of ∼1.1 μGy can be acquired. When a watch with a moving second hand was used as an object, the dynamic X-ray imaging can be realized under a dose rate of 55 μGy·s. Our results demonstrate that LuO:Eu nanoscintillators can be regarded as candidate materials for dynamic digital radiographic imaging.