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Manipulation of chemical and optical properties of MgO nanocubes via surface functionalization
|Slavica Stankic 1, Thomas Berger 1, Oliver Diwald 1, Johannes Bernardi 2, Erich Knoezinger 1
1. Institute of Materials Chemistry, Vienna University of Technology (TU), Veterinärplatz 1, Wien 1210, Austria
We use chemical vapour deposition (CVD) for the synthesis of pure and doped MgO nanoparticles. In this presentation we demonstrate how the admixture of a second metal component alters the electronic surface properties of MgO nanocrystals. When MgO nanoparticles are doped with monovalent Li-ions, traces of a dopant already induce dramatic changes in the optical and chemical surface properties. Isovalent Ca2+ cations can be distributed homogeneously in MgO nanocrystals although CaMgO mixtures are thermodynamically forbidden on a macroscopic scale. Subsequent thermal activation leads to calcium ion segregation into the MgO surface. These CaMgO nanocrystals represent novel materials with enhanced surface basicity and a higher thermal stability in comparison to pure MgO. Furthermore, an unexpected photonic behaviour of those mixtures is reflected by dramatically increase in photoluminescence emission which is also red-shifted with respect to pure MgO. On the contrary, the admixture of also isovalent but larger Sr2+ cations induces a blue-shifted emission irrespective of the excitation wavelength.
Presentation: Oral at E-MRS Fall Meeting 2006, Symposium C, by Slavica Stankic
See On-line Journal of E-MRS Fall Meeting 2006
Submitted: 2006-05-15 11:22 Revised: 2009-06-07 00:44