Design, fabrication and characterization of nanocaged 12CaO•7Al2O3:Tb3+ photostimulable phosphor for high-quality X-ray imaging

It has been a challenge to realize high-quality X-ray imaging using oxide-based phosphors for avoiding halogenide-based materials and satisfying the requirements of environmental protection. In this study, lanthanide-doped nanocaged 12CaO center dot 7Al(2)O(3):Tb3+ (C12A7:Tb3+) X-ray imaging phosphors with strong photostimulated luminescence (PSL) have been prepared using a combustion method. X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), Fourier transforminfrared (FTIR) spectra, scanning electron microscopy (SEM) and transmission electron microscope (TEM) measurements suggest that single-phased C12A7:Tb3+ powders with an average grain size ranging from several hundred nanometers to several micrometers have been obtained at the ignition temperature from 700 to 900 degrees C. PSL, thermoluminescence (TL), electron spin resonance (ESR) and photoconductivity analyses indicate that the storage time of X-ray image exceeds 48 h due to the existence of deep traps in the C12A7:Tb3+ phosphor. High-quality X-ray imaging with a resolution of 15 line pairs per mm has been achieved using the phosphor. High conversion efficiency is achieved at 1.28 pJ/mm(2)/mR, suggesting the application potential of the phosphors in X-ray imaging and medical diagnostics. (C) 2017 Elsevier Ltd. All rights reserved.