Enhance the photoluminescence and radioluminescence of La2Zr2O7:Eu3+ core nanoparticles by coating with a thin Y2O3 shell

We report the generation of La2Zr2O7:5%Eu3+@Y2O3 (LZO5E@YO) core@shell crystalline inorganic-inorganic heterogeneous nanoparticles (NPs). The Y2O3 (YO) shell coating process based on a chemical sol-gel method led to the growth of a thin YO shell on the ordered pyrochlore La2Zr2O7:5%Eu3+ (LZO5E) core NPs. Photoluminescence (PL) analyses demonstrated a blue shift of 15 nm on charge transfer (CT) excitation band of the core@shell NPs from that of the core NPs. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) along x-ray diffraction (XRD), Fourier-transform Infrared spectroscopy (FTIR) and x-ray photoelectron spectroscopy (XPS) studies confirmed the formation of the thin YO layer over the LZO5E core NPs. The PL intensity of the LZO5E@YO core@shell NPs was enhanced by three fold compared to that of the LZO5E core NPs, and higher quantum yield (QY) was observed for the former compared to the original NPs by more than 70%. Higher radioluminescence (RL) emission was also observed for the core@shell NPs compared to the core NPs. Our ability of obtaining near-perfect core@shell heterostructure with enhanced luminescence performance opens the door for the development of efficient La2Zr2O7:5%Eu3+@Y2O3 NPs for both optical and x-ray scintillation applications. La2Zr2O7:5%Eu3+@Y2O3 core@shell nanoparticles (NPs) were designed to enhance the photoluminescence and radioluminescence of the original La2Zr2O7:5%Eu3+ (LZO5E) core NPs, as shown with the central diagram. Blue colored spheres represent the LZO5E core NPs, gray color represents the intermediate carbon coating, golden green color represents the coating gel precursor for Y2O3, and the dark orange color represents the Y2O3 (YO) shell. [Display omitted] •La2Zr2O7:5mol%Eu and La2Zr2O7:5mol%Eu@Y2O3 NPs were synthesized.•Both the core and core@shell NPs emit at ∼612 nm after UV excitation.•A blue shift of 15 nm on charge transfer band was observed from the core@shell NPs compared to the core NPs.•The core@shell NPs show an >70% increase over the core NPs in PL QY excited at 243 nm.•Under X-ray excitation, the core@shell NPs also show 4.5-fold increased RL than the core NPs.