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Title: Touch sensors based on planar liquid crystal-gated-organic field-effect transistors

We report a tactile touch sensor based on a planar liquid crystal-gated-organic field-effect transistor (LC-g-OFET) structure. The LC-g-OFET touch sensors were fabricated by forming the 10 μm thick LC layer (4-cyano-4{sup ′}-pentylbiphenyl - 5CB) on top of the 50 nm thick channel layer (poly(3-hexylthiophene) - P3HT) that is coated on the in-plane aligned drain/source/gate electrodes (indium-tin oxide - ITO). As an external physical stimulation to examine the tactile touch performance, a weak nitrogen flow (83.3 μl/s) was employed to stimulate the LC layer of the touch device. The LC-g-OFET device exhibited p-type transistor characteristics with a hole mobility of 1.5 cm{sup 2}/Vs, but no sensing current by the nitrogen flow touch was measured at sufficiently high drain (V{sub D}) and gate (V{sub G}) voltages. However, a clear sensing current signal was detected at lower voltages, which was quite sensitive to the combination of V{sub D} and V{sub G}. The best voltage combination was V{sub D} = −0.2 V and V{sub G} = −1 V for the highest ratio of signal currents to base currents (i.e., signal-to-noise ratio). The change in the LC alignment upon the nitrogen flow touch was assigned as the mechanism for the present LC-g-OFET touch sensors.
Authors:
; ; ; ; ;  [1] ;  [1] ;  [2] ;  [3] ; ;  [4]
  1. Organic Nanoelectronics Laboratory, Department of Chemical Engineering and Graduate School of Applied Chemical Engineering, Kyungpook National University, Daegu, 702-701 (Korea, Republic of)
  2. (Korea, Republic of)
  3. School of Materials Science and Engineering, Kyungpook National University, Daegu, 702-701 (Korea, Republic of)
  4. Department of Polymer Science and Engineering and Graduate School of Applied Chemical Engineering, Kyungpook National University, Daegu, 702-701 (Korea, Republic of)
Publication Date:
OSTI Identifier:
22299768
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 4; Journal Issue: 9; Other Information: (c) 2014 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; ELECTRIC POTENTIAL; FIELD EFFECT TRANSISTORS; HOLE MOBILITY; LAYERS; LIQUID CRYSTALS; NITROGEN; SENSORS; SIGNAL-TO-NOISE RATIO; STIMULATION; TIN OXIDES