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A wrist-worn eccentric rotor-based energy harvester utilizing multiple magnetically plucked flower petal-shaped bimorph lead zirconate titanate (PZT) thin-film beams was designed and fabricated. The bimorph beams were formed by depositing {001} oriented PZT films up to 5.4 mu m in thickness on both sides of a 50 mu m thick nickel foil. The prototype was characterized with an analytical system-level model and a bench-top swing-arm test set-up. The prototype can achieve approximately 40 mu W power output from a bench-top pseudo walking motion input. Further simulation suggests that improvement can be made by growing thicker PZT layers.
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Strongly (001) Oriented Bimorph PZT Film on Metal Foils Grown by rf ‐Sputtering for Wrist‐Worn Piezoelectric Energy Harvesters
Abstract For piezoelectric energy harvesters, a large volume of piezoelectric material with a high figure of merit is essential to obtain a higher power density. The work describes the growth of highly (001) oriented sputtered lead zirconate titanate (PZT) films (f≈ 0.99) exceeding 4 µm in thickness on both sides of an Ni foil to produce a bimorph structure. These films are incorporated in novel wrist‐worn energy harvesters (<16 cm2) in which piezoelectric beams are plucked magnetically using an eccentric rotor with embedded magnets to implement frequency up‐conversion. The resulting devices successfully convert low‐frequency vibration sources (i.e., from walking, rotating the wrist, and jogging) to higher frequency vibrations of the PZT beams (100–200 Hz). Measured at resonance, six beams producing an output of 1.2 mW is achieved at 0.15 G acceleration. For magnetic plucking of a wrist‐worn nonresonant device, 40–50 µW is produced during mild activity.
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- Award ID(s):
- 1160483
- PAR ID:
- 10065042
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Functional Materials
- Volume:
- 28
- Issue:
- 36
- ISSN:
- 1616-301X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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