Lead-free KNbO3 ferroelectric nanorod based flexible nanogenerators and capacitors
In spite of high piezoelectricity, only a few one-dimensional ferroelectric nano-materials with perovskite structure have been used for piezoelectric nanogenerator applications. In this paper, we report high output electrical signals, i.e. an open-circuit voltage of 3.2 V and a closed-circuit curren...
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Published in | Nanotechnology Vol. 23; no. 37; p. 375401 |
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Main Authors | , , , , , , , |
Format | Journal Article |
Language | English |
Published |
England
IOP Publishing
21.09.2012
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Online Access | Get full text |
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Summary: | In spite of high piezoelectricity, only a few one-dimensional ferroelectric nano-materials with perovskite structure have been used for piezoelectric nanogenerator applications. In this paper, we report high output electrical signals, i.e. an open-circuit voltage of 3.2 V and a closed-circuit current of 67.5 nA (current density 9.3 nA cm−2) at 0.38% strain and 15.2% s−1 strain rate, using randomly aligned lead-free KNbO3 ferroelectric nanorods (∼1 μm length) with piezoelectric coefficient (d33 ∼ 55 pm V −1). A flexible piezoelectric nanogenerator is mainly composed of KNbO3-poly(dimethylsiloxane) (PDMS) composite sandwiched by Au/Cr-coated polymer substrates. We deposit a thin poly(methyl methacrylate) (PMMA) layer between the KNbO3-PDMS composite and the Au/Cr electrode to completely prevent dielectric breakdown during electrical poling and to significantly reduce leakage current during excessive straining. The flexible KNbO3-PDMS composite device shows a nearly frequency-independent dielectric constant (∼3.2) and low dielectric loss (<0.006) for the frequency range of 102-105 Hz. These results imply that short and randomly aligned ferroelectric nanorods can be used for a flexible high output nanogenerator as well as high-k capacitor applications by performing electrical poling and further optimizing the device structure. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0957-4484 1361-6528 |
DOI: | 10.1088/0957-4484/23/37/375401 |