Improving Piezoelectric Nanogenerator Comprises ZnO Nanowires by Bending the Flexible PET Substrate at Low Vibration Frequency

The well-aligned and vertical ZnO nanowires were grown on PET substrates by the hydrothermal method. The novel piezoelectric nanogenerator was fabricated from ZnO nanowires and a Pt/ZnO nanowire electrode on a flexible PET substrate. A sample was compressed and bent generating internal stress in the PET substrate, which output a current of approximately 5 × 10–10 A without a source of vibration. The sample with 2% bending was also measured with vibration at a low frequency, yielding a maximum piezoelectric current of about 2.5 × 10–7 A, which is 4 times the current of a nonbending sample. These results demonstrate that a little bending of a flexible substrate improves piezoelectric performance.