微电极尺寸对双电层电容和电荷转移电阻的影响

Size of Microelectrode Influence on Electrical Double-Layer Capacitor and Charge Transfer Resistance

微电极广泛应用于神经电信号检测,微电极的尺寸直接影响记录的神经电信号。建立了神经电信号检测的等效分析电路模型,基于GCS双电层理论以及PNP方程建立了微电极表面双电层分析模型。采用COMSOL仿真及微电极交流阻抗谱测试,分析了双电层电容与微电极尺寸的关系。分析结果表明:微电极表面积越大,电荷转移电阻越小,双电层电容越大;单位面积电容与微电极半径成反比例关系。

Microelectrodes are widely used in the detection of neuroelectric signals.The size of microelectrodes directly affects the recorded neuroelectric signals.The equivalent analysis circuit model of neuroelectric signal detection was established,and the double electric layer analysis model of microelectrode surface was established based on GCS double electric layer theory and PNP equation.The relationship between double layer capacitance and microelectrode size was analyzed by COMSOL simulation and measurement of microelectrode AC impedance spectrum.The analysis results show that the larger the microelectrode surface area is,the smaller the charge transfer resistance is,and the larger the double layer capacitance is;the capacitance per unit area is inversely proportional to the microelectrode radius.