| AVS 55th International Symposium & Exhibition | |
| Nanometer-scale Science and Technology | Tuesday Sessions |
| Session NS+NC-TuA |
| Session: | Nanowires and Nanosize Effects |
| Presenter: | A. Kumar, University of Central Florida |
| Authors: | A. Kumar, University of Central Florida S.B. Krishna, University of Central Florida S. Seal, University of Central Florida |
| Correspondent: | Click to Email |
Ceria (CeO2) is a rare earth metal oxide known for possessing less toxicity than many other metal oxides. Although the beneficial therapeutic properties of ceria nanoparticles have been explored, poor emission properties limit its application in imaging. The continuing quest to understand the interaction of ceria nanoparticles with cell requires better luminescent property of ceria, for which a nanoscale manipulation by doping has been reported. Europium is known for its strong emission and its atomic radii being close to that of cerium favors extensive solid solubility in ceria lattice. A systematic approach has been used to optimize emission intensity by varying the dopant concentration and annealing temperature. The doped oxide particles were synthesized by room temperature chemical precipitation technique. The size and morphology of the particles were characterized by high-resolution transmission electron microcopy (HRTEM). Strain induced on doping was calculated through X-ray Diffraction (XRD) from Williamson-Hall plot and is found to increase with the amount of dopant and decreases with annealing temperature. The emission property of europium doped ceria nanoparticles were studied by photoluminescence spectra. In order to disseminate the influence of surface chemical species, oxidation state, oxygen vacancy and strain on emission, X-ray photoelectron (XPS), Raman and Infra-red (IR) spectral characterizations were carried out. XPS results indicated that the ratio of Ce3+/Ce4+increases with dopant concentration and decreases with annealing temperature. Raman studies show a progressive shift to the higher energy due to local symmetry ordering with the temperature. Emission intensity varies with the wavelength of excitation and observed transitions indicate the presence of Eu3+ in different symmetry environments. The photoluminescence was found to be optimum at 15mol% Eu doped ceria and gets quenched with further doping concentration. Emission spectrum of the doped cerium oxide reveals peak characteristic to energy transfer from host to Eu3+ and this becomes more efficient on annealing. The present results are likely to have a profound impact not only for simultaneous therapeutic and imaging, but also on using ceria as carrier under physiological conditions. The study indicates that the enhanced photoluminescence is related to the manipulation of ceria lattice at nanoscale achieved through doping of suitable element.