| Pacific Rim Symposium on Surfaces, Coatings and Interfaces (PacSurf 2014) | |
| Energy Harvesting & Storage | Wednesday Sessions |
| Session EH-WeP |
| Session: | Energy Harvesting & Storage Poster Session |
| Presenter: | MoolKyul Kang, Korea Electronics Technology Institute (KETI), Republic of Korea |
| Authors: | M.K. Kang, Korea Electronics Technology Institute (KETI), Republic of Korea J.H. Park, Korea Electronics Technology Institute (KETI), Republic of Korea K.I. Lee, Korea Electronics Technology Institute (KETI), Republic of Korea B.K. Ju, Korea University, Republic of Korea C.S. Lee, Korea Electronics Technology Institute (KETI), Republic of Korea |
| Correspondent: | Click to Email |
ZnO nanowires (NWs) can be grown by chemical approach at low temperature (<100 ℃) on any substrate and any shape substrate. A relatively small force is required to induce the mechanical agitation, so that it can be fabricated sensitive devices.[1] But piezoelectric device based on ZnO NWs, which can not improve the piezoelectric properties of a single material due to a low piezoelectric d constant of ZnO NWs (d≃12pC/N).
In this paper, we demonstrated fully flexible and transparent piezoelectric touch sensor based on ZnO NWs, and composed that touch sensor with BaTiO3 of Perovskite structure for improving piezoelectric properties. In order to maintain the flexibility of sensing spot, the BaTiO3 (10 wt%) are dispersed in flexibility-improved SiO2 capping solution and coated on ZnO NWs surface as a capping layer by spray coating method. Also, By replacing Indium tin oxide (ITO) electrodes with transparent flexible CNT-Ag nanowires electrode, the flexibility of the entire structure was enhanced. ITO is commonly used as transparent electrodes. However due to its high cost and limited supply of indium, the fragility and lack of flexibility of ITO layer, its alternative are being sought. It is expected that conductive films using carbon nanotubes and Ag NWs could be a prospective relacement of ITOs.
The ZnO NWs based sensor generated the output voltage of ~ 50 mV. The sensor with BaTiO3 generates a higher output voltage (~1.2 V) than a ZnO NWs based sensor. We confirmed that the output voltage of sensor with ZnO NWs and BaTiO3 was dramatically increased. We measured the resistance of capping layer and CNT-Ag NWs electrode during the periodic bending. When bent and flexed over 1,000 cycles, the films did not show significant degradation in sheet resistance compared to Ag thin film and ITO film on the same PET substrate. The bending test results conducted to confirm the mechanical stability of capping layer and CNT-Ag NWs as a electrode. The measurement results suggest that the our Piezoelectric touch sensors are suitable for flexible device such as flexible touch sensor, wearable and rollable touch panel.
[1] Zhong Lin Wang, "Piezopotential gated nanowire devices: Piezotronics and piezo phototronics", Nano Today, 5, 2010, pp.540~552