Enhanced radioluminescence of NaLuF4:Eu3+ nanoscintillators by terbium sensitization for X-ray imaging

X-ray excited luminescence (XEL) of scintillators is significant for imaging applications in the fields of medical detection, information retrieval, and scientific research. In this case, lanthanide-doped rare-earth nanophosphors show potential as next-generation scintillators owing to their facile synthesis, high chemical stability and photostability, and adjustable XEL emission. In this study, a new type of XEL-enhanced NaLuF4-based nanophosphor was synthesized by doping Tb3+ to sensitize the emission of Eu3+, facilitating the application of the as-prepared nanoscintillators for X-ray imaging on opaque samples and biological specimens. NaLuF4:Gd/Tb/Eu with 5% Tb-doping showed the highest XEL intensity owing to the energy transfer process between Tb3+ and Eu3+. The NaLuF4:Gd/Tb/Eu (10/5/15 mol%) nanoparticles exhibited an excellent scintillation performance with a high light yield of 15 313 photons MeV−1 and low detection limit of 84.1 nGyair s−1. The X-ray imaging test using the NaLuF4:Gd/Tb/Eu (10/5/15 mol%)-based scintillation film exhibited a high spatial resolution of 8.7 lp mm−1. Furthermore, the NaLuF4:Gd/Tb/Eu (10/5/15 mol%)-based scintillation film was applied in X-ray imaging with high contrast for a spring sealed in a capsule and a crab.