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Sensors 2009, 9(11), 8911-8923; doi:10.3390/s91108911

Miniaturized pH Sensors Based on Zinc Oxide Nanotubes/Nanorods

* ,
Department of Science and Technology (ITN), Campus Norrköping, Linköping University, SE-60174 Norrköping, Sweden
* Author to whom correspondence should be addressed.
Received: 22 September 2009 / Revised: 19 October 2009 / Accepted: 19 October 2009 / Published: 9 November 2009
(This article belongs to the Special Issue Metal-Oxide Based Nanosensors)
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ZnO nanotubes and nanorods grown on gold thin film were used to create pH sensor devices. The developed ZnO nanotube and nanorod pH sensors display good reproducibility, repeatability and long-term stability and exhibit a pH-dependent electrochemical potential difference versus an Ag/AgCl reference electrode over a large dynamic pH range. We found the ZnO nanotubes provide sensitivity as high as twice that of the ZnO nanorods, which can be ascribed to the fact that small dimensional ZnO nanotubes have a higher level of surface and subsurface oxygen vacancies and provide a larger effective surface area with higher surface-to-volume ratio as compared to ZnO nanorods, thus affording the ZnO nanotube pH sensor a higher sensitivity. Experimental results indicate ZnO nanotubes can be used in pH sensor applications with improved performance. Moreover, the ZnO nanotube arrays may find potential application as a novel material for measurements of intracellular biochemical species within single living cells.
Keywords: ZnO nanotubes; ZnO nanorods; pH sensors; potentiometric measurements ZnO nanotubes; ZnO nanorods; pH sensors; potentiometric measurements
This is an open access article distributed under the Creative Commons Attribution License (CC BY) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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Fulati, A.; Usman Ali, S.M.; Riaz, M.; Amin, G.; Nur, O.; Willander, M. Miniaturized pH Sensors Based on Zinc Oxide Nanotubes/Nanorods. Sensors 2009, 9, 8911-8923.

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