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Title: Fluoroethylenepropylene ferroelectret films with cross-tunnel structure for piezoelectric transducers and micro energy harvesters

Layered fluoroethylenepropylene (FEP) ferroelectret films with cross-tunnel structure were fabricated from sheets of FEP films by template-patterning followed by a fusion-bonding process and contact charging. The typical piezoelectric d{sub 33} coefficients, measured by a quasi-static method of samples not annealed, are in the range of 1000–3700 pC/N. The resonance behavior of the samples is analyzed by dielectric spectroscopy which also yields Young's modulus. Microphones built with such films exhibit a somewhat decreasing frequency response up to 1 kHz, an increase of the responses due to diffraction effects at higher frequencies, and eventually a peak probably due to a thickness resonance at about 40 kHz. Annealing at 125 °C indicates that the sensitivity stabilizes at about 40% of the original value. From this data, stable dynamic d{sub 33} coefficients of up to 300 pC/N can be calculated. A micro energy harvesting generator utilizing these films and based on the excitation of thickness vibrations is also described. With an active area of 4.3 cm{sup 2} and a seismic mass of 69.5 g, power up to 0.5 μW referred to an acceleration of 1 g can be generated at a frequency of 120 Hz.
Authors:
 [1] ;  [2] ;  [3] ;  [1]
  1. School of Physics Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092 (China)
  2. (Germany)
  3. Institute for Telecommunications Technology, TU Darmstadt, Merckstrasse 25, 64283 Darmstadt (Germany)
Publication Date:
OSTI Identifier:
22314305
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 7; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ANNEALING; BONDING; DIELECTRIC MATERIALS; DIFFRACTION; EXCITATION; FILMS; KHZ RANGE 01-100; PIEZOELECTRICITY; THICKNESS; TRANSDUCERS; YOUNG MODULUS