| Summary: | 碩士 === 國立中興大學 === 材料科學與工程學系所 === 101 === Replacing batteries by harvesting energy from human respiration is a promising technology for self-powered systems using the concept of nanogenerators (NGs). ZnO is a semiconductor material with unique piezoelectric property has been discussed recently. A novel ZnO nanogenerator with a flexible and highly lightweight substrate has the potential of harvesting energy from human respiration. We introduce a lifting-off method of ZnO nanowires from Si substrate and embedded in flexible films-epoxy resin has been proposed. Flexible films served as the secondary and flexible substrate after ZnO nanowires transferring from the Si substrate. The piezoelectric potential of a ZnO nanogenerator can produce AC power output during respiration. For normal human respiration at an air flow rate of 2.0 ms-1 and tidal volume 500 mL, the ZnO nanogenerator generates current-density and voltages of 3.65 nA and 27.32 mV, respectively. The electrical performance reached the highest value of 11.21 nA and 67.25 mV at an air flow rate of 5.0 ms-1 and tidal volume 1000 mL.
To obtain the high-output piezoelectric performance, fold-up fabrication method is introduced and polydimethylsiloxane (PDMS) is used as the flexible film. The thickness of the 2-fold ZnO NG was approximately 25 μm, and the 16-fold ZnO NG had a comparatively low size of approximately 200 μm. The 16-fold ZnO NG generates approximately 0.6 V and 0.5 μA at the air flow rate of 2.0 ms-1, while generating approximately 1.3 V and 0.8 μA at the air flow rate of 5.0 ms-1. The lift-off and fold-up methods are both candidates for creating devices that can harvest energy from human respiration.
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