School of Chemical and Physical Science, Victoria University of Wellington, Wellington, New Zealand.
The MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington, New Zealand.
PLoS One. 2022 Jun 16;17(6):e0270164. doi: 10.1371/journal.pone.0270164. eCollection 2022.
Microelectrodes are commonly used in electrochemical analysis and biological sensing applications owing to their miniaturised dimensions. It is often desirable to improve the performance of microelectrodes by reducing their electrochemical impedance for increasing the signal-to-noise of the recorded signals. One successful route is to incorporate nanomaterials directly onto microelectrodes; however, it is essential that these fabrication routes are simple and repeatable. In this article, we demonstrate how to synthesise metal encapsulated ZnO nanowires (Cr/Au-ZnO NWs, Ti-ZnO NWs and Pt-ZnO NWs) to reduce the impedance of the microelectrodes. Electrochemical impedance modelling and characterisation of Cr/Au-ZnO NWs, Ti-ZnO NWs and Pt-ZnO NWs are carried out in conjunction with controls of planar Cr/Au and pristine ZnO NWs. It was found that the ZnO NW microelectrodes that were encapsulated with a 10 nm thin layer of Ti or Pt demonstrated the lowest electrochemical impedance of 400 ± 25 kΩ at 1 kHz. The Ti and Pt encapsulated ZnO NWs have the potential to offer an alternative microelectrode modality that could be attractive to electrochemical and biological sensing applications.
微电极由于其微型化的尺寸，常用于电化学分析和生物传感应用。通过降低其电化学阻抗来提高记录信号的信噪比，从而提高微电极的性能，这通常是可取的。一种成功的方法是将纳米材料直接掺入微电极中；然而，这些制造方法必须简单且可重复。在本文中，我们展示了如何合成金属封装的氧化锌纳米线（Cr/Au-ZnO NWs、Ti-ZnO NWs 和 Pt-ZnO NWs）以降低微电极的阻抗。对 Cr/Au-ZnO NWs、Ti-ZnO NWs 和 Pt-ZnO NWs 进行了电化学阻抗建模和表征，并结合对平面 Cr/Au 和原始 ZnO NWs 的控制进行了研究。结果发现，用 10nm 厚的 Ti 或 Pt 封装的 ZnO NW 微电极在 1kHz 时表现出最低的电化学阻抗为 400±25kΩ。Ti 和 Pt 封装的 ZnO NWs 有可能提供一种替代的微电极模式，这可能对电化学和生物传感应用具有吸引力。
