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

38 Citations (Scopus)


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
Issue number4
Publication statusPublished - 2019 Jan 24


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

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics


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