Gd3+-sensitized rare earth fluoride scintillators for High-resolution flexible X-ray imaging

X-ray imaging technology is widely used in the medical, industrial, and scientific fields, where highly sensitive, flexible, and cost-effective scintillation screens are crucial prerequisites. In this work, YF3:Gd3+/Tb3+ micro particles (MPs) were prepared via an ultrafast chemical precipitation method and exhibited excellent luminescent properties under the excitation of ultraviolet light and X-ray. It was found that Gd3+ doping could effectively enhance the photoluminescence (PL) and X-ray activated radioluminescence (RL) of Tb3+ owing to an efficient energy transfer process from Gd3+ to Tb3+. The prepared YF3:30%Gd3+/10%Tb3+ MPs exhibited fine environmental stability and superb X-ray RL, which was stronger than that of commercial scintillators Bi4Ge3O12 (BGO) and even comparable to that of CsI:TI single crystal. Highly flexible transparent YF3:Gd3+/Tb3+/PDMS scintillation screens were prepared to record high-resolution X-ray images of planar/nonplanar objects, where the imaging spatial resolution was 16.8 lp mm-1, which was far higher than the standard spatial resolutions required for medical computed tomography (CT) scan (2 lp mm-1) and X-ray imaging (3.5 lp mm-1). The excellent scintillation performance, superior flexibility and environmental stability of YF3:Gd3+/Tb3+/PDMS scintillation films endow them with the potential application in high-resolution industrial nondestructive inspection and biological imaging.