Pressure-sensing properties of single-walled carbon nanotubes covered with a corona-poled piezoelectric polymer

Journal Article · Mon Jul 18 04:00:00 EDT 2016 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4959091· OSTI ID:22594476

Ikawa, Takeshi; Tabata, Hiroshi; Yoshizawa, Takeshi; Utaka, Ken; Kubo, Osamu; Katayama, Mitsuhiro ^[1]

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1. Division of Electrical, Electronic and Information Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)

Single-walled carbon nanotubes (SWNTs) have been studied extensively as sensing elements for chemical and biochemical sensors because of their excellent electrical properties, their ultrahigh ratio of surface area to volume, and the consequent extremely high sensitivity of their surface to the surrounding environment. The extremely high sensitivity indicates that SWNTs can operate as excellent transducers when combined with piezoelectric materials. In this paper, we present a touch sensor based on SWNT thin-film transistors (SWNT-TFTs) covered with a thin film of the piezoelectric polymer poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)). Devices were fabricated by spin-coating a P(VDF-TrFE) layer on an SWNT-TFT, which was followed by in situ corona poling to polarize the P(VDF-TrFE) layer. We studied the effect of the corona polarity on the device characteristics and revealed that poling with a negative corona discharge induced a large amount of hole doping in the SWNTs and improved the touch-sensing performance of the devices, while a positive discharge had a negligible effect. The poled devices exhibited regular, stable, and positive drain current modulation in response to intermittent pressing, and the response was proportional to the magnitude of the applied pressure, suggesting that it was caused by the piezoelectric effect of the polarized P(VDF-TrFE) layer. Furthermore, we also fabricated a device using horizontally aligned SWNTs with a lower SWNT density as an alternative transducer to an SWNT thin film, which demonstrated sensitivity as high as 70%/MPa.

• OSTI ID: 22594476
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 3 Vol. 109; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CARBON NANOTUBES
CORONA DISCHARGES
ELECTRICAL PROPERTIES
FLUORINATED ALIPHATIC HYDROCARBONS
LAYERS
PIEZOELECTRICITY
POLYVINYLS
PRESSING
SENSITIVITY
SENSORS
SPIN-ON COATING
SURFACE AREA
THIN FILMS
TRANSDUCERS
TRANSISTORS
WALLS