Mixed Triboelectric and Flexoelectric Charge Transfer at the Nanoscale

Huimin Qiao, Pin Zhao, Owoong Kwon, Ahrum Sohn, Fangping Zhuo, Dong Min Lee, Changhyo Sun, Daehee Seol, Daesu Lee, Sang Woo Kim, Yunseok Kim

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


The triboelectric effect is a ubiquitous phenomenon in which the surfaces of two materials are easily charged during the contact-separation process. Despite the widespread consequences and applications, the charging mechanisms are not sufficiently understood. Here, the authors report that, in the presence of a strain gradient, the charge transfer is a result of competition between flexoelectricity and triboelectricity, which could enhance charge transfer during triboelectric measurements when the charge transfers of both effects are in the same direction. When they are in the opposite directions, the direction and amount of charge transfer could be modulated by the competition between flexoelectric and triboelectric effects, which leads to a distinctive phenomenon, that is, the charge transfer is reversed with varying forces. The subsequent results on the electrical power output signals from the triboelectrification support the proposed mechanism. Therefore, the present study emphasizes the key role of the flexoelectric effect through experimental approaches, and suggests that both the amount and direction of charge transfer can be modulated by manipulating the mixed triboelectric and flexoelectric effects. This finding may provide important information on the triboelectric effect and can be further extended to serve as a guideline for material selection during a nanopatterned device design.

Original languageEnglish
Article number2101793
JournalAdvanced Science
Issue number20
Publication statusPublished - 2021 Oct 20

Bibliographical note

Funding Information:
H.Q. and P.Z. contributed equally to this work. This work was supported by a National Research Foundation of Korea (NRF) grant (No. 2019R1I1A1A01063888 and No. 2019R1A6A1A03033215) and the Nano Material Technology Development Program (2020M3H4A1A03084600) of NRF funded by the Korean government (MSIP). F.Z. acknowledges the Alexander von Humboldt Foundation for its financial support.

Publisher Copyright:
© 2021 The Authors. Advanced Science published by Wiley-VCH GmbH

All Science Journal Classification (ASJC) codes

  • Medicine (miscellaneous)
  • Chemical Engineering(all)
  • Materials Science(all)
  • Biochemistry, Genetics and Molecular Biology (miscellaneous)
  • Engineering(all)
  • Physics and Astronomy(all)


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