Facile Fabrication of Carbon Ultramicro- to Nanoelectrode Arrays with Tunable Voltammetric Response

详细信息    查看全文

• 作者：Jonathon Duay ; Jacob M. Goran ; Keith J. Stevenson
• 刊名：Analytical Chemistry
• 出版年：2014
• 出版时间：December 2, 2014
• 年：2014
• 卷：86
• 期：23
• 页码：11528-11532
• 全文大小：364K
• ISSN：1520-6882

文摘

The voltammetric response for nano- to micrometer-sized electrode arrays are represented by two major regimes: a sigmoidal shaped i鈥?i>v response for arrays acting as individual electrodes in parallel and peak-shaped i鈥?i>v response for arrays acting as an ensemble in concert. Here, we present a facile and versatile technique to fabricate ultramicro- to nanoelectrode arrays using atomic layer deposition of insulating Al₂O₃ on conductive carbon films masked by 1.54, 11, or 90-渭m-diameter polystyrene spheres (PSS). The ratio between the interelectrode distance and the electrode radii of the electrode arrays is a predictable function of the PSS radius used in fabrication, resulting in electrode arrays with a tunable voltammetric response. Arrays are characterized utilizing cyclic voltammetry and electrochemical impedance spectroscopy, which provides the critical scan rate, 谓_crit, the scan rate at which the radial diffusion layers of the individual electrodes overlap and appear as a single linear diffusion layer. Thus, below 谓_crit, the electrode has a peak-shaped i鈥?i>v response associated with semi-infinite linear diffusion, whereas above this critical scan rate, the i鈥?i>v response is sigmoidal as a result of hemispherical radial diffusion. Results indicate that the critical scan rates are 6.6, 1.0, and 0.01 V/s for the 1.54, 11, and 90 渭m PSS prepared electrode arrays, respectively.