Abstract 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.

中文翻译：

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刚性和柔性金属基板上的高质量 PMMA/ZnO NWs 压电涂层

摘要 本文报告了沉积在金属柔性基板上的压电纳米结构与刚性基板作为能量收集器的新架构的比较研究。刚性金属基板是多层类型的 Pt/Ti/SiO2/Si 或 Au/Ti/SiO2/Si，而 Ti 箔是柔性金属基板。活性压电层由在低温下通过水热法生长的垂直 ZnO 纳米线 (ZnO NW) 阵列组成，该阵列在先前沉积的晶种（成核）溶胶-凝胶层上并覆盖有一层聚甲基丙烯酸甲酯 (PMMA)。新获得的纳米结构已在不同的制备阶段通过 X 射线衍射、扫描和透射电子显微镜、原子力显微镜、光谱椭偏仪进行表征。通过测量 d33 系数评估 PMMA/(ZnO NWs)/Ti 结构的压电性能。结果表明，ZnO 纳米线在柔性基板上成功生长，压电系数是刚性基板的四倍。通过改进 ZnO 纳米线在柔性金属基板上的垂直集成，PMMA/(ZnO 纳米线)/Ti 经济实惠的纳米结构为无线或国防技术以及可穿戴或可植入生物医学系统作为高效收集器的集成开辟了道路。