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ISRN Materials Science
Volume 2012 (2012), Article ID 894072, 5 pages
Research Article

Enhanced Size-Dependent Piezoelectricity in Nanostructured T i O 2 Films

Department of Computer Science, University of Verona, Strada Le Grazie, 15, 37134 Verona, Italy

Received 25 January 2012; Accepted 16 February 2012

Academic Editors: Y. Masuda and R. Mota

Copyright © 2012 V. Dallacasa. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


We have developed a nanogenerator that is driven by mechanical forces to produce continuous direct-current output. The nanogenerator was fabricated with titanium dioxide nanoparticle arrays forming a Schottky barrier with a conducting electrode with a small gap. Under uniaxial mechanical compression, nanogenerators have shown repeatable and consistent electrical outputs with energy-conversion efficiency of order of magnitude at least comparable to similar nanogenerators based on piezoelectric materials. Flexoelectricity due to inhomogeneous strain induced in the nanostructured T i O 2 film has been identified as one possible mechanism of the high apparent piezoelectricity in the nanoparticles. The approach presents an adaptable, mobile, and cost-effective technology for harvesting mechanical energy from the environment. At the present stage it offers a potential solution for powering nanodevices.