High-quality PMMA/ZnO NWs piezoelectric coating on rigid and flexible metallic substrates

• Published in: Applied surface science 2020-11, Vol.529, p.147135, Article 147135
• Main Authors: Chelu, M., Stroescu, H., Anastasescu, M., Calderon-Moreno, J.M., Preda, S., Stoica, M., Fogarassy, Z., Petrik, P., Gheorghe, M., Parvulescu, C., Brasoveanu, C., Dinescu, A., Moldovan, C., Gartner, M.
• Format: Article
• Language: English
• Subjects: Energy harvesting; Flexible metallic substrate; Piezoelectric effect; PMMA; ZnO NWs
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2020.147135

[Display omitted] •New piezoelectric structures were deposited on flexible and rigid metallic substrates.•Well-aligned ZnO nanowires were successfully grown by the hydrothermal method.•The structure on the flexible substrate has shown the highest piezoelectric coefficient.•PMMA/ZnO NWs/Ti is a promising piezoelectric structure for nano energy harvesters. This paper reports the comparative study of piezoelectric nanostructures deposited on metallic flexible substrate versus rigid substrates as a new architecture for energy harvesters. Rigid metallic substrates are multi-layered types of Pt/Ti/SiO2/Si or Au/Ti/SiO2/Si while Ti foil is a flexible metallic substrate. The active piezo-layer consisted of a vertical ZnO nanowires (ZnO NWs) array grown by the hydrothermal method at low temperature, on a previously deposited crystalline seed (nucleation) sol-gel layer and covered with a layer of polymethylmethacrylate (PMMA). The new obtained nanostructures have been characterized in different stages of preparation by X-Ray Diffraction, Scanning and Transmission Electron Microscopy, Atomic Force Microscopy, Spectroscopic Ellipsometry. The piezoelectric performance of PMMA/(ZnO NWs)/Ti structures was evaluated by measuring the d33 coefficient. Results show that ZnO nanowires have successfully grown on the flexible substrates with a piezoelectric coefficient four times greater than on rigid substrates. By improving vertical integration of ZnO NWs on flexible metallic substrate, PMMA/(ZnO NWs)/Ti affordable nanostructures open the way towards integration in wireless or defence technologies and in wearable or implantable biomedical systems as efficient harvester.