| AVS 55th International Symposium & Exhibition | |
| In Situ Microscopy and Spectroscopy: Interfacial and Nanoscale Science Topical Conference | Wednesday Sessions |
| Session IS+SY+SS-WeM |
| Session: | In Situ Spectroscopy – Interfacial Science and Catalysis |
| Presenter: | J. Dorman, University of California at Los Angeles |
| Authors: | Y. Mao, University of California at Los Angeles J. Dorman, University of California at Los Angeles J.P. Chang, University of California at Los Angeles |
| Correspondent: | Click to Email |
Nanostructured crystalline inorganic solid oxides show various intriguing properties and process many important technological applications. To better control the property and device performance of materials, growth kinetic and mechanistic information of structure changes should be pursued to provide feedback for the development of new “designer” materials to meet the challenges of the future. Time-resolved in situ experimentation represents the most likely means, especially with the synchrotron radiation as the x-ray source due to its high energy flux. In this study, we focus on advanced luminescent nanomaterials, since they have practical applications in nearly all devices involving the artificial production of light and are applicable in nanoscaled electronics, photonics, display and advanced bioanalysis. In this talk, we present our recent investigation by in-situ time-resolved synchrotron x-ray diffraction (XRD) and absorption spectroscopy (XAS) on the synthesis of rare-earth doped metal oxide nanostructures, including Er:Y2O3 nanotubes and nanoparticles and Er: La2(ZrxHf1-x)2O7 nanoparticles, by hydrothermal and molten-salt syntheses.1,2,3 Our results demonstrate that in situ XRD and XAS data support each other. For the hydrothermal synthesis of Er:Y(OH)3 nanotubes, the hydroxide phase starts to form immediately and continues to grow. For the dehydration process from Er:Y(OH)3 nanotubes to Er:Y2O3 nanotubes, the dehydration starts at ~250°C and completes at 450°C and an intermediate oxyhydroxide phase was found for the first time. Furthermore, the in situ XRD study provided guidance on the selection of proper annealing temperature for the molten salt synthesis of Er:Y2O3 and Er: La2(ZrxHf1-x)2O7 nanoparticles. Their growth kinetics will be obtained from further investigation of these processes under different ramp rates and reaction temperatures.
1 Mao, et al. Synthesis and luminescence properties of erbium-doped Y2O3 nanotubes, J. Phys. Chem. C, 112, 2278 (2008).
2 Mao, et al. Molten salt synthesis of highly luminescent erbium-doped yttrium oxide nanoparticles, submitted (2008).
3 Mao, et al. La2Zr2O7 and La2Hf2O7 nanoparticles from single-source complex precursors: kinetically modified synthesis and luminescent properties, submitted (2008).