YIN Jun, ZHANG Zhuhua, LI Xuemei, YU Jin, ZHOU Jianxin, CHEN Yaqing, GUO Wanlin. Waving potential in graphene. Nature Communications 2014, 5, 3582.

NATURE COMMUNICATIONS | ARTICLE

Waving potential in graphene

Jun Yin, Zhuhua Zhang, Xuemei Li, Jin Yu, Jianxin Zhou, Yaqing Chen & Wanlin Guo

These authors contributed equally to this work
Jun Yin & Zhuhua Zhang

Affiliations
State Key Laboratory of Mechanics and Control of Mechanical Structures, The Key Laboratory of Intelligent Nano Materials and Devices of DoE, Institute of Nano Science, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
Jun Yin, Zhuhua Zhang, Xuemei Li, Jin Yu, Jianxin Zhou, Yaqing Chen & Wanlin Guo

Contributions
W.G. and J.Yin conceived the experiments; J.Yin and X.L. performed the experiments; Z.Z. and J.Yu performed the calculations; W.G., Z.Z. and J.Yin analysed the data; and W.G. and Z.Z. wrote the paper. All authors discussed the results and commented on the manuscript.

Competing financial interests
The authors declare no competing financial interests.

Corresponding author
Correspondence to: Wanlin Guo

Nature Communications 5, Article number: 3582 doi:10.1038/ncomms4582
Received 01 October 2012 Accepted 07 March 2014 Published 06 May 2014

Abstract
Nanoscale materials offer much promise in the pursuit of high-efficient energy conversion technology owing to their exceptional sensitivity to external stimulus. In particular, experiments have demonstrated that flowing water over carbon nanotubes can generate electric voltages. However, the reported flow-induced voltages are in wide discrepancy and the proposed mechanisms remain conflictive. Here we find that moving a liquid–gas boundary along a piece of graphene can induce a waving potential of up to 0.1 V. The potential is proportional to the moving velocity and the graphene length inserted into ionic solutions, but sharply decreases with increasing graphene layers and vanishes in other materials. This waving potential arises from charge transfer in graphene driven by a moving boundary of an electric double layer between graphene and ionic solutions. The results reveal a unique electrokinetic phenomenon and open prospects for functional sensors, such as tsunami monitors.

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