Multiaxial and Transparent Strain Sensors Based on Synergetically Reinforced and Orthogonally Cracked Hetero-Nanocrystal Solids

Woo Seok Lee, Donggyu Kim, Byeonghak Park, Hyungmok Joh, Ho Kun Woo, Yun Kun Hong, Tae il Kim, Don Hyung Ha, Soong Ju Oh

Research output: Contribution to journalArticlepeer-review

42 Citations (Scopus)

Abstract

Wearable strain sensors are widely researched as core components in electronic skin. However, their limited capability of detecting only a single axial strain, and their low sensitivity, stability, opacity, and high production costs hinder their use in advanced applications. Herein, multiaxially highly sensitive, optically transparent, chemically stable, and solution-processed strain sensors are demonstrated. Transparent indium tin oxide and zinc oxide nanocrystals serve as metallic and insulating components in a metal–insulator matrix and as active materials for strain gauges. Synergetic sensitivity- and stability-reinforcing agents are developed using a transparent SU-8 polymer to enhance the sensitivity and encapsulate the devices, elevating the gauge factor up to over 3000 by blocking the reconnection of cracks caused by the Poisson effect. Cross-shaped patterns with an orthogonal crack strategy are developed to detect a complex multiaxial strain, efficiently distinguishing strains applied in various directions with high sensitivity and selectivity. Finally, all-transparent wearable strain sensors with Ag nanowire electrodes are fabricated using an all-solution process, which effectively measure not only the human motion or emotion, but also the multiaxial strains occurring during human motion in real time. The strategies can provide a pathway to realize cost-effective and high-performance wearable sensors for advanced applications such as bio-integrated devices.

Original languageEnglish
Article number1806714
JournalAdvanced Functional Materials
Volume29
Issue number4
DOIs
Publication statusPublished - 2019 Jan 24

Bibliographical note

Funding Information:
W.S.L. and D.K. contributed equally to this work. This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by Ministry of Science, ICT, and Future Planning (2016R1C1B2006534). This research was also supported by Creative Materials Discovery Program through the National Research Foundation of Korea (NRF) funded by Ministry of Science and ICT (NRF-2018M3D1A1059001). This work was partially supported by Basic Science Research Program (NRF-2017R1D1A1B03033089) through the National Research Foundation of Korea funded by the Ministry of Science, ICT, and Future Planning. This research was also supported by the Korea University Graduate School Junior Fellow Research Grant.

Publisher Copyright:
© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Keywords

  • Poisson effect
  • hetero-nanocrystals
  • multiaxial strain sensors
  • orthogonal cracks
  • transparent electronics

ASJC Scopus subject areas

  • General Chemistry
  • General Materials Science
  • Condensed Matter Physics

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