Zhang Xiaoling, Wang Yunjiao, Zheng Jiahui, Yang Chen, Wang Deqiang
School of Smart Health, Chongqing Polytechnic University of Electronic Technology, Chongqing 401331, China.
Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China.
Micromachines (Basel). 2024 Sep 23;15(9):1176. doi: 10.3390/mi15091176.
This study presents a theoretical investigation into the voltammetric behavior of bipolar interfacial nanopores due to the effect of potential scan rate (1-1000 V/s). Finite element method (FEM) is utilized to explore the current-voltage (I-V) properties of bipolar interfacial nanopores at different bulk salt concentrations. The results demonstrate a strong impact of the scan rate on the I-V response of bipolar interfacial nanopores, particularly at relatively low concentrations. Hysteresis loops are observed in bipolar interfacial nanopores under specific scan rates and potential ranges and divided by a cross-point potential that remains unaffected by the scan rate employed. This indicates that the current in bipolar interfacial nanopores is not just reliant on the bias potential that is imposed but also on the previous conditions within the nanopore, exhibiting history-dependent or memory effects. This scan-rate-dependent current-voltage response is found to be significantly influenced by the length of the nanopore (membrane thickness). Thicker membranes exhibit a more pronounced scan-rate-dependent phenomenon, as the mass transfer of ionic species is slower relative to the potential scan rate. Additionally, unlike conventional bipolar nanopores, the ion current passing through bipolar interfacial nanopores is minimally affected by the membrane thickness, making it easier to detect.
本研究对双极界面纳米孔在电位扫描速率（1 - 1000 V/s）影响下的伏安行为进行了理论研究。采用有限元方法（FEM）探究了不同本体盐浓度下双极界面纳米孔的电流 - 电压（I - V）特性。结果表明，扫描速率对双极界面纳米孔的I - V响应有强烈影响，尤其是在相对较低浓度时。在特定扫描速率和电位范围内，双极界面纳米孔中观察到滞后回线，并由一个不受所用扫描速率影响的交叉点电位分隔。这表明双极界面纳米孔中的电流不仅依赖于施加的偏置电位，还依赖于纳米孔内的先前条件，呈现出历史依赖性或记忆效应。发现这种依赖于扫描速率的电流 - 电压响应受纳米孔长度（膜厚度）的显著影响。较厚的膜表现出更明显的依赖于扫描速率的现象，因为离子物种的传质相对于电位扫描速率较慢。此外，与传统双极纳米孔不同，通过双极界面纳米孔的离子电流受膜厚度的影响最小，更易于检测。
