9871864 Tissue A systematic and extensive study of the physical, optical, and dynamical properties of lanthanide-doped metal-oxide nanostructures will be performed. These novel materials have potential applications as materials for lasers and optical amplifiers, and as phosphors for flat-panel displays. This work will assist in developing a theoretical and practical framework to optimize the optical properties of metal-oxide nanocrystals and nanocomposites. A reduction in particle size for micron-size materials has often resulted in a reduction in optical emission due to quenching by surface defects. There are experimental indications that finite size effects in nanocrystals can significantly enhance the oscillator strength of impurity transitions. In addition, modifications to the phonon density-of-states, and to the strength of the electron-phonon interaction, will undoubtedly influence non-radiative relaxation rates in nanoparticle systems. Applications in the display industry require smaller particle size for both high-resolution and low voltage flat-panel displays. At the same time, they also require rugged and high-efficiency materials. Therefore, the optical and dynamical properties of the nanocrystals will be characterized both alone and after passivation by surface modification or by embedding in a matrix. The approach will be to prepare nanostructured materials, and characterize their structure and morphology by X-ray diffraction, transmission-electron microscopy, atomic-force microscopy, and fluorescence spectroscopy at Virginia Tech. Well-characterized nanostructured materials will then be studied at the University of Georgia using high-resolution spectroscopic techniques to determine how fundamental properties such as oscillator strength, optical dephasing, non-radiative relaxation, phonon dynamics, and energy-transfer processes depend on particle size or surface modification. The collaboration between Virginia Tech and the University of Georgia brings together expertise in nanocrystalline synthesis, processing, and characterization, with expertise in high resolution and nonlinear spectroscopic techniques. The close collaboration between synthesis and spectroscopy groups will allow the PIs to systematically grow and characterize new materials, with property measurements providing rapid feedback to guide material preparation and processing. The synergism of this collaboration will allow much more progress in preparing and understanding very complex nanostructures than if the groups were working alone %%% Novel lanthanide-doped metal-oxide nanostructured materials have potential applications as materials for lasers and optical amplifiers, and as phosphors for flat-panel displays. The results of this research will provide feedback to engineer nanostructures to improve the properties of these materials. The interdisciplinary nature of the collaboration between Virginia Tech and the University of Georgia will provide an excellent educational experience to train future scientists for the multidisciplinary teamwork that is increasingly characteristic of scientific research and technological development. This project is funded as part of Nanotechnology Initiative by the Ceramics and the Solid State Chemistry programs in the Division of Materials Research, the Physical Foundations and Enabling Technologies program in the Division of Electrical and Communication Systems, and the Office of Multidisciplinary Activities in the Mathematical and Physical Sciences Directorate. In addition, the Division of International Programs has provided funding for travel in order for the PIs to perform collaborative research with their counterparts in Russia.
