Impedance Spectroscopy of Spin-Cast and Electrochemically Deposited PEDOT:PSS Films on Microfabricated Electrodes with Various Areas
Impedance Spectroscopy of Spin-Cast and Electrochemically Deposited PEDOT:PSS Films on Microfabricated Electrodes with Various Areas
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DOI：
10.1002/celc.201700297
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发表时间：
2017-09-01
期刊：
影响因子：
4
通讯作者：
Martin, David C.
中科院分区：
文献类型：
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作者：
Koutsouras, Dimitrios A.;Gkoupidenis, Paschalis;Martin, David C.
我们使用定制设计的微加工基板检查了 PEDOT：PSS 涂层金电极在各种电解质中随时间频率（0.1 至 104 Hz）的函数的电化学阻抗谱 (EIS)。电极面积的标称尺寸在从 10 x 10 μ m (100 μ m(2)) 到 500 x 500 μ m (2.5 x 10(5) μ m(2)) 的广泛范围内系统地变化。对与 GOPS 交联的旋涂 PEDOT: PSS 和具有相似厚度的电化学沉积 PEDOT: PSS 薄膜进行了比较。不同尺寸的 PEDOT: PSS 涂层电极的阻抗谱都可以通过具有溶液电阻 R-s 和薄膜电容 C 的二元等效电路模型来合理地描述。这两个参数共同定义了特征时间频率 f(c)= 1/(2 pi RsC)。通过将阻抗相对于 R-s (Z(n)=竖条 Z 竖条/R-s) 和频率相对于 f(c) (f(n)=f/f(c)) 归一化，我们发现所有实验波特曲线都可以折叠到 Z(n) 与 f(n) 的单个主图上。此外，还推导出了能够估计薄膜阻抗幅度 Z 竖条和相位 phi 的分析公式并进行了实验验证。这些结果具有根本意义，并且预计对于用于连接生物医学设备与活体组织的共轭聚合物薄膜的设计、表征和优化也很重要。
We have examined the electrochemical impedance spectroscopy (EIS) of PEDOT: PSS-coated gold electrodes in various electrolytes as a function of temporal frequency (from 0.1 to 104 Hz) by using a custom-designed microfabricated substrate. The electrode areas were systematically varied over a broad range in nominal size from 10 x 10 mu m (100 mu m(2)) to 500 x 500 mu m (2.5 x 10(5) mu m(2)). Comparisons were made between spincast PEDOT: PSS crosslinked with GOPS and electrochemically deposited PEDOT: PSS films with similar thicknesses. The impedance spectra of the PEDOT: PSS-coated electrodes with various sizes could all be reasonably well described by a two-element equivalent circuit model with a solution resistance R-s and a film capacitance C. These two parameters together define a characteristic temporal frequency f(c)= 1/(2 pi RsC). By normalizing the impedance with respect to R-s (Z(n)=vertical bar Z vertical bar/R-s) and the frequency with respect to f(c) (f(n)=f/f(c)), we found that all of the experimental Bode curves could be collapsed onto a single master plot of Z(n) vs. f(n). In addition, analytical formulas that allow the estimation of the film impedance magnitude vertical bar Z vertical bar and phase phi were derived and experimentally validated. These results are of fundamental interest and are also anticipated to be important for the design, characterization, and optimization of conjugated polymer films for interfacing biomedical devices with living tissue.