虑及栅电极极化及吸附电荷影响的有机电化学晶体管Ⅰ-Ⅴ特性研究  

Current-Voltage Characteristics of Organic Electrochemical Transistors Considering Effects of Gate Polarization and Adsorbed Charge

作　　者：刘燃 彭钰博 黄庆 杨兴[4] 贾月梅 杜衍[5] 冀健龙 LIU Ran;PENG Yu-Bo;HUANG Qing;YANG Xing;JIA Yue-Mei;DU Yan;JI Jian-Long(College of Mechanical and Vehicle Engineering,Taiyuan University of Technology,Jinzhong 030600,China;College of Biomedicine Engineering,Taiyuan University of Technology,Jinzhong 030600,China;Department of Laboratory Medicine,Army Medical University,Chongqing 400042,China;MEMS Lab,Department of Precision Instruments&Mechanology,Tsinghua University,Beijing 100084,China;State Key Laboratory of Electroanalytical Chemistry,Changchun Institute of Applied Chemistry,Chinese Academy of Sciences,Changchun 130022,China;College of Information and Computer,Taiyuan University of Technology,Jinzhong 030600,China;School of Integrated Circuits,Tsinghua University,Beijing 100084,China)

机构地区：[1]太原理工大学机械与运载工程学院,晋中030600 [2]太原理工大学生物医学工程学院,晋中030600 [3]陆军军医大学大坪医院检验科,重庆400042 [4]清华大学精密仪器与机械学系微机电系统实验室,北京100084 [5]中国科学院长春应用化学研究所,电分析化学国家重点实验室,长春130022 [6]太原理工大学信息与计算机学院,晋中030600 [7]清华大学集成电路学院,北京100084

出　　处：《分析化学》2022年第6期878-888,共11页Chinese Journal of Analytical Chemistry

基　　金：国家自然科学基金项目(No.52175542);山西省自然科学基金项目(No.20210302123136);重庆市自然科学基金项目(No.cstc2020jcyjmsxmX 0002);中国博士后基金项目(No.2020M673646);吉林省科技发展计划项目重点研发项目(No.20210204126YY)资助。

摘　　要：有机电化学晶体管(OECT)具有良好的生物兼容性、较低的工作电压以及优异的信号放大能力等特点,被广泛应用于生物传感领域。栅电极修饰是利用OECT进行生物传感的关键,但现有OECT理论无法描述栅电极极化与电荷吸附对电流-电压(I-V)特性关系的影响。本研究通过构建栅电极/电解液、半导体沟道/电解液界面微分电容串联模型修正了Bernards-Malliaras I-V特性关系,并通过实验研究讨论了此修正模型的有效性,具体包括改变恒电位电沉积时间调控栅电极表面PEDOT:PSS薄膜厚度(0.80~3.73μm)以及栅电极/电解液界面电容(CG)(24.01~120.10μF)。结果表明,OECT跨导峰值随着CG的增加而增大;设置栅电极电压(VG)为+0.6 V时,半导体沟道电流(IDS,l)随着CG的增大而单调上升;设置VG为–0.6 V时,IDS,l随着CG的增大而单调下降。在OECT栅电极上修饰适配体探针,并使之与不同浓度的三磷酸腺苷(10^(-12)~10^(-5)mol/L)发生特异性结合反应,结果表明,IDS,l随三磷酸腺苷浓度即吸附电荷量的增大而减小。定性理论分析结果与实验测试结果一致。本研究提出的修正理论模型有望为OECT及基于OECT的生物传感器的设计提供理论支持。Organic electrochemical transistors(OECTs)are widely used in biosensing due to their good biocompatibility, low operating voltage, and excellent signal amplification ability. Functionalization of the gate electrode is crucial for OECTs-based biosensing. However, the existing theory cannot describe the influences of polarization and charge adsorption on the current-voltage(I-V)characteristics. In this work, the Bernards-Malliaras I-V characteristic is modified by constructing the series model of differential capacitance formed at gate/electrolyte and semiconductor-channel/electrolyte interfaces. The effectiveness of the modified model is discussed by experimental investigations, including changing the potentiostatic electrodeposition time, regulating the thickness of poly(3,4-ethylenedioxythio-phene)∶poly(styrenesulfonate)(PEDOT∶PSS)film formed on the surface of the gate-electrode(0.80–3.73 μm)and the gate-electrode/electrolyte interface capacitance(CG)(24.01–120.10 μF). Experimental results show that the transconductance peak increases with the CG increments;when the gate electrode voltage(VG)is set as +0.6 V, the current flowing in the semiconductor channel current(IDS,l)increases monotonically with the CG increments;When VG is set as –0.6 V, IDS,l decreases monotonically with the CG increments. In addition, the aptamer probes anchored on the gate-electrode react specifically with different concentrations of adenosine triphosphate(10^(-12)–10^(-5) mol/L).Experimental results show that IDS,l decreases with the increments of the adenosine triphosphate concentration,and thus, the amount of adsorbed charge. The qualitative theoretical analyses are consistent with the experimental results. The modified theoretical model proposed herein is expected to provide theoretical support for designing of OECTs and OECTs based biosensors.

关 键 词：有机电化学晶体管 生物传感器 电极极化 吸附电荷 

分 类 号：TN32[电子电信—物理电子学]