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TitleOptimization of sol-gel-formed ZnO:Al processing parameters by observation of dopant ion location using solid-state 27Al NMR spectrometry
Publication TypeJournal Article
Year of Publication2011
AuthorsKemmitt, T., Ingham B., and Linklater R.
JournalJournal of Physical Chemistry C
Pagination15031 - 15039
Date Published2011
ISSN19327447 (ISSN)
KeywordsAl incorporation, Al-doping, Alcohols, aluminum, Aluminum ions, Amino alcohols, Calcination, Degree of control, Dopant ions, Drying step, Gels, Ions, Lattice sites, NMR spectrometry, nuclear magnetic resonance, Optimal conditions, Optimization, Powders, Processing condition, Processing parameters, Resonance, Scanning electron microscopy, Sol precursors, Sol-gel process, Sol-gels, Sols, Spectrometry, X ray diffraction, X ray powder diffraction, Zinc oxide, ZnO, ZnO powder
AbstractWe report the discrimination of Al doping sites in sol-gel-formed ZnO powders by solid-state 27Al nuclear magnetic resonance (NMR) spectrometry. A degree of control of dopant placement is demonstrated by modifying sol precursors and processing parameters. ZnO powders containing 1-8 at. % aluminum ions were prepared from aqueous citrate-amino-alcohol-based gels calcined at 500 °C. The powders were characterized using 27Al NMR spectrometry, X-ray diffraction (XRD), and scanning electron microscopy (SEM). Solid-state 27Al NMR spectrometry clearly distinguished between different Al environments and was effective in determining the relative amounts of incorporation of Al dopant ions into the Zn lattice sites in the zincite structure. This allowed a synthesis protocol to be developed to optimize the doping effectiveness. Relatively minor variations in processing conditions could influence the degree and mode of Al incorporation. Optimal conditions were found to include a 90 °C drying step, followed by placement in a preheated (500 °C) furnace for 1 h. An ethanolamine-containing precursor was shown to perform much better than precursors containing alternative amino alcohols. © 2011 American Chemical Society.

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