Influence of Water on the Performance of Organic Electrochemical Transistors
Influence of Water on the Performance of Organic Electrochemical Transistors
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DOI：
10.1021/acs.chemmater.8b04335
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发表时间：
2019-02-12
影响因子：
8.6
通讯作者：
Inal, Sahika
中科院分区：
文献类型：
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作者：
Savva, Achilleas;Cendra, Camila;Inal, Sahika
由有机混合导体组成的有机电化学晶体管（OECTs）可以在水性生物介质中工作，并将生物起源的低幅度离子波动转化为可测量的电信号。对这些生物传感器日益增长的技术兴趣使得对离子-电子耦合的基本理解对于新材料和设备的设计极其重要。在这个过程中，迄今为止被忽视的一个关键方面是在设备操作期间由膜吸收的水及其对设备性能的影响。在这里，使用一系列相同的电解质与不同的离子浓度，我们量化的水的量，被纳入到一个亲水性的p-型有机半导体薄膜旁边的掺杂剂阴离子和调查电化学掺杂后，在膜中发生的结构和形态的变化。我们表明，渗透到膜中的水合掺杂剂离子不可逆地改变聚合物结构，并产生负面影响的效率，可逆性和速度的电荷产生。当较少的水注入到通道中时，OECT表现出更高的介电常数和更快的切换速度。虽然溶胀通常被认为是有效的离子-电子转换的必要条件，但这项工作揭示了溶胀通道材料对累积模式OECTs性能的负面影响，并为未来的材料设计奠定了基础。
Organic electrochemical transistors (OECTs) composed of organic mixed conductors can operate in aqueous, biological media and translate low-magnitude ionic fluctuations of biological origin into measurable electrical signals. The growing technological interest in these biotransducers makes the fundamental understanding of ion-to-electron coupling extremely important for the design of new materials and devices. One crucial aspect in this process that has been so far disregarded is the water taken up by the film during device operation and its effects on device performance. Here, using a series of the same electrolyte with varying ion concentrations, we quantify the amount of water that is incorporated into a hydrophilic p-type organic semiconductor film alongside the dopant anions and investigate structural and morphological changes occurring in the film upon electrochemical doping. We show that infiltration of the hydrated dopant ions into the film irreversibly changes the polymer structure and negatively impacts the efficiency, reversibility, and speed of charge generation. When less water is injected into the channel, OECTs exhibit higher transconductance and faster switching speeds. Although swelling is commonly suggested to be a necessity for efficient ion-to-electron transduction, this work uncovers the negative impact of a swollen channel material on the performance of accumulation mode OECTs and lays the foundation for future materials design.