Department of Physics, Chonnam National University, Gwangju 61186, Republic of Korea.
Nanotechnology. 2020 Feb 7;31(7):075401. doi: 10.1088/1361-6528/ab53b8. Epub 2019 Nov 1.
Enhanced stability of a piezoelectric nanogenerator (PNG) was demonstrated using c- and m-axis GaN/VO core-shell nanowires (NWs) by analyzing the capacitive coupling of the PNG's output. The NW array grown on GaN thin film was embedded in polydimethylsiloxane (PDMS) matrix, following which the matrix was transferred to an indium (In)-coated PET substrate for achieving superior flexibility of the PNG. The stability of the PNG was enhanced by holding the NW PDMS composite with a PDMS polymer as a bonding material on the PET substrate. The inserted PDMS layer improved the lifetime of the PNG, however, because of the insulating nature of PDMS, the piezoelectric output of GaN NWs was coupled capacitively to In contact on PET substrate and it resulted in a slight degradation of piezoelectric output due to the voltage drop across the bottom capacitive contact. The maximum piezoelectric current was 64 nA and output voltage was 11.9 V from the PNG with c-axis NWs. While the PNG with direct bottom contact exhibited 57% output reduction after 72 000 operation cycles, the PNG with capacitive contact did not show any degradation in stability even after 150 000 cycles.
通过分析压电纳米发电机 (PNG) 的输出电容耦合，使用 c 轴和 m 轴 GaN/VO 核壳纳米线 (NW) 增强了 PNG 的稳定性。在 GaN 薄膜上生长的 NW 阵列被嵌入聚二甲基硅氧烷 (PDMS) 基质中，然后将基质转移到涂有铟 (In) 的 PET 基底上，以实现 PNG 的卓越柔韧性。通过将 NW-PDMS 复合材料与 PDMS 聚合物作为键合材料固定在 PET 基底上，提高了 PNG 的稳定性。插入的 PDMS 层延长了 PNG 的寿命，但由于 PDMS 的绝缘性质，GaN NWs 的压电输出被电容耦合到 PET 基底上的 In 接触，导致由于底部电容接触的电压降，压电输出略有下降。具有 c 轴 NW 的 PNG 的最大压电电流为 64 nA，输出电压为 11.9 V。而具有直接底部接触的 PNG 在 72000 次操作循环后输出减少了 57%，而具有电容接触的 PNG 在 150000 次循环后稳定性没有任何降低。
