PEDOT交流电沉积制备及其物质输运机理
摘要
物理化学流体动力学是近代流体力学的一个重要分支，主要讨论流体流动与物理、化学等过程的相互作用关系。在电化学沉积过程中，反应物质首先要从电解质溶液中输运到电极表面，之后在电极表面发生反应，沉积在电极表面。在电解质溶液中物质的输运模型主要包括：扩散、电迁移和对流。当电化学反应的电信号是交流电时，由于电场的不均匀分布，粒子将发生极化，产生电力矩。在交流不均匀的电场中，极化的粒子将受介电泳力产生运动。基于物理化学流体动力学理论，本文主要做了以下工作：
1、使用3,4乙烯二氧噻吩（EDOT）与聚(4-苯乙烯磺酸钠（NaPSS）的混合水溶液为电解液，采用交流电化学聚合沉积的方法，在Pt微电极间通过调整聚合过程中的电学参数（通过改变电压幅值、频率、直流偏置）等，制备出具有不同形貌结构（膜状、枝晶状、线状）的聚（3,4乙烯二氧噻吩）：聚（苯乙烯磺酸）（PEDOT:PSS）结构。使用扫描电子显微镜（SEM）、原子力显微镜（AFM）和拉曼光谱（Raman Spectra）对其进行表征分析。结果表明：（1）电压幅值越高，电极上产生相应的成核位点越多。（2）电压频率影响沉积形成PEDOT:PSS形貌特征，当频率升高时，形貌从膜状变成枝晶状和线状。（3）直流偏置影响沉积过程的物质生长方向，PEDOT:PSS更倾向于在正偏压处生长。（4）电压幅值和频率会对PEDOT:PSS分子结构产生影响。电压幅值增大，频率升高，PEDOT:PSS出现表面凹凸不平、内部形成孔洞、断链等结构缺陷
2、采用计时电流法、循环伏安法和交流电化学阻抗谱研究了EDOT单体与PSS-在聚合沉积过程中的微流体传质机理。结果表明：（1）EDOT单体的氧化电位是+0.9V，过氧化电位是+1.2V。（2）聚合沉积的过程中，扩散受限，电极反应速率受溶液中反应物质传质速率限制。（3）聚合沉积反应过程主要分为两个步骤：1）EDOT单体和PSS-物质吸附在电极表面。2）EDOT 和PSS-在电极表面聚合沉积，形成PEDOT:PSS。（4）电化学聚合沉积过程与物质在溶液中的传质过程在同一时间常数内，两个过程相互影响。
deposition3、并用COMSOL软件进行仿真模拟，验证输运机理的正确性。利用溶液中的物质的输运机理，来解释实验现象。结论如下：（1）在电化学聚合沉积过程中，EDOT单体氧化形成阳离子自由基。阳离子自由基会沿着电场方向产生电迁移，与其他单体发生反应，会聚合形成二聚体。二聚体继续氧化聚合，形成低聚物。（2）中性粒子如单体、二聚体和低聚物在不均匀电场中受到介电泳力的作用，集中在电极对之间的中心区域。（3）当中心区域的粒子浓度变高，当粒子足够接近，彼此间将通过聚合力形成偶极子。（4）当电压幅值越大、频率越高，介电泳力，电泳力以及分子将的聚合力将越大，聚合形成的PEDOT:PSS结构则更加紧密。
4、使用3,4乙烯二氧噻吩（EDOT）与聚(4-苯乙烯磺酸钠（NaPSS）的混合水溶液为电解液，采用交流电沉积法在Pt微电极对之间制备沉积形成薄膜、线、枝晶等不同形貌结构的有机半导体（OS）沟道层。以NaCl电解质作为栅介质，Ag/AgCl电极作为栅极，一对Pt微电极中一个为源极，另一个为漏极，
制备形成有机电化学晶体管（OECT）。对器件性能进行分析，结果如下：（1）对不同形貌结构的PEDOT:PSS沟道层的OECTs器件性
能进行分析，结果表明，膜状沟道层器件的性能最好。（2）使用石墨烯量子进行掺杂，探究掺杂石墨烯量子点对器件性能的影响。结果表明，当电解液
⁄时，制备的OECTs的性能最好。（3）对交流电GQDs的质量浓度为2μg L
化学聚合沉积制备膜状有机半导体沟道层的OECTs进行重复性实验，结果表明，微电极尺寸一样，采用相同的电学参数，这种方法拥有良好的重复性。
关键词：PEDOT, 交流电沉积, 物质输运机理, 有机电化学晶体管
PEDOT AC ELECTRODEPOSITION PREPARATION AND THE MATTERIAL TRANSPORT MECHANISM
ABSTRACT
Physicochemical hydrodynamics is an important branch of modern hydrodynamics. It mainly discusses the interaction between fluid flow and physical and chemical processes. This paper mainly
explores the physicochemical hydrodynamics of electrochemical processes. In the process of electrochemical deposition, the reactants are first transported from the electrolyte solution to the electrode surface, then reacted on the electrode surface and deposited on the electrode surface. The transport models of substances in electrolyte solutions mainly include diffusion, electromigration and convection. When the electric signal of electrochemical reaction is alternating current, due to the uneven distribution of electric field, the particles will polarize and generate electrostatic moment. In an AC inhomogeneous electric field, the polarized particles will be moved by dielectrophoresis force. Based on the theory of physicochemical hydrodynamics, the main work of this paper is as follows:
1. Using the mixed aqueous solution of 3,4-ethylenedioxythiophene (EDOT) and poly (sodium 4-styrene sulfonate (NaPSS) as electrolyte and AC
electrochemical polymerization deposition method, P with different morphologies (membrane, dendritic, linear) was prepared by adjusting the electrical parameters (voltage amplitude, frequency, DC bias) during the polymerization process between Pt microelectrodes. EDOT:PSS structure. Scanning electron microscopy (SEM), atomic force microscopy (AFM) and Raman spectra (Raman Spectra) were used for characterization and analysis. The results show that: (1) The higher the voltage amplitude, the more nucleation points will be generated on the electrode. (2) V oltage freque
ncy affects the formation of PEDOT:PSS morphology. When the frequency increases, the morphology changes from film to dendritic and linear. (3) DC bias affects the direction of material growth during deposition. PEDOT: PSS tends to grow at positive bias. (4) V oltage amplitude and frequency affect the molecular structure of PEDOT: PSS. With the increase of voltage amplitude and frequency, the surface of PEDOT: PSS is uneven, and the structure defects such as holes and broken chains will be formed in the interior of PEDOT: PSS.
2. Charge transfer kinetics and material transport mechanism of EDOT monomer and PSS-in the process of polymer deposition were studied by chronoamperometry, cyclic voltammetry and AC chemical impedance spectroscopy. The results show that: (1) The oxidation potential of EDOT monomer is + 0.9V and the peroxide potential is + 1.2V. (2) In the process of polymer deposition, the diffusion of material is limited, and the reaction rate of electrode is affected by the mass transfer rate in solution. (3) Polymerization and

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