Improvement in Strain Sensor Stability by Adapting the Metal Contact Layer

Ji Yeon Choy, Eun Bee Jo, Chang Joo Yim, Hae Kyung Youi, Jung Hoon Hwang, Jun Ho Lee, Hyun Seok Kim

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

Research on stretchable strain sensors is actively conducted due to increasing interest in wearable devices. However, typical studies have focused on improving the elasticity of the electrode. Therefore, methods of directly connecting wire or attaching conductive tape to materials to detect deformation have been used to evaluate the performance of strain sensors. Polyaniline (PANI), a p-type semiconductive polymer, has been widely used for stretchable electrodes. However, conventional procedures have limitations in determining an appropriate metal for ohmic contact with PANI. Materials that are generally used for connection with PANI form an undesirable metal-semiconductor junction and have significant contact resistance. Hence, they degrade sensor performance. This study secured ohmic contact by adapting Au thin film as the metal contact layer (the MCL), with lower contact resistance and a larger work function than PANI. Additionally, we presented a buffer layer using hard polydimethylsiloxane (PDMS) and structured it into a dumbbell shape to protect the metal from deformation. As a result, we enhanced steadiness and repeatability up to 50% strain by comparing the gauge factors and the relative resistance changes. Consequently, adapting structural methods (the MCL and the dumbbell shape) to a device can result in strain sensors with promising stability, as well as high stretchability.

Original languageEnglish
Article number630
JournalSensors
Volume22
Issue number2
DOIs
StatePublished - 1 Jan 2022

Keywords

  • PDMS
  • Polyaniline
  • Strain sensor
  • Stretchable sensor
  • Wearable device

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