Nanowire Architectures Improve Ion Uptake Kinetics in Conjugated Polymer Electrochemical Transistors
Nanowire Architectures Improve Ion Uptake Kinetics in Conjugated Polymer Electrochemical Transistors
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DOI：
10.1021/acsami.1c08176
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发表时间：
2021-07-16
影响因子：
9.5
通讯作者：
Ginger, David S.
中科院分区：
文献类型：
--
作者：
Giridharagopal, Rajiv;Guo, Jiajie;Ginger, David S.
有机电化学晶体管被认为在优化离子迁移率和电子迁移率之间面临固有的材料设计张力。这些器件将离子吸收吸收到电流中，从而需要高离子迁移率以实现有效的电化学掺杂和快速的开启动力学以及高电子迁移率以实现最大的电致发光。在这里，我们探索了一种简便的路线，以提高操作动力学和体积电容的高迁移率共轭聚合物（聚[2，5-（2-辛基十二烷基）-3，6-二酮吡咯并吡咯-alt-5，5-（2，5-二（噻吩-2-基）噻吩并[3，2-B]噻吩DPP-DTT）通过采用纳米线形态。对于相等的厚度，与纯DPP-DTT膜相比，DPP-DTT纳米线膜表现出一致更快的动力学（类似于快6- 10倍）。纳米线架构显示出类似于4倍的更高体积电容，从7.1增加到27.7 F/cm（3），与多孔结构一致，更好地使整个膜的离子吸收。纳米线还表现出类似于17 mV的阈值电压的小但能量有利的偏移，使得纳米结构化系统与纯膜相比更快且能量上更容易电化学掺杂。我们解释的变化，使用两种原子力显微镜方法：原位电化学应变显微镜和纳米红外成像通过光诱导力显微镜。这些数据表明，纳米线膜的结构允许整个活性层更大的溶胀和离子吸收，表明纳米线架构表现出体积操作，而纯膜主要通过场效应操作。我们建议，对于更高的迁移率的材料，铸造在纳米线形式的活性层可以提供更快的动力学，增强的体积电容，并可能降低阈值电压，同时保持理想的器件性能。
Organic electrochemical transistors are believed to face an inherent material design tension between optimizing for ion mobility and for electronic mobility. These devices transduce ion uptake into electrical current, thereby requiring high ion mobility for efficient electrochemical doping and rapid turn-on kinetics and high electronic mobility for the maximum transconductance. Here, we explore a facile route to improve operational kinetics and volumetric capacitance in a high-mobility conjugated polymer (poly[2,5-(2-octyldodecyl)-3,6-diketopyrrolopyrrole-alt-5,5-(2,5-di(thien-2-yl)thieno [3,2-b] thiophenen DPP-DTT) by employing a nanowire morphology. For equivalent thicknesses, the DPP-DTT nanowire films exhibit consistently faster kinetics (similar to 6-10x faster) compared to a neat DPP-DTT film. The nanowire architectures show similar to 4x higher volumetric capacitance, increasing from 7.1 to 27.7 F/cm(3), consistent with the porous structure better enabling ion uptake throughout the film. The nanowires also exhibit a small but energetically favorable shift in a threshold voltage of similar to 17 mV, making the nanostructured system both faster and energetically easier to electrochemically dope compared to neat films. We explain the variation using two atomic force microscopy methods: in situ electrochemical strain microscopy and nanoinfrared imaging via photoinduced force microscopy. These data show that the nanowire film's structure allows greater swelling and ion uptake throughout the active layer, indicating that the nanowire architecture exhibits volumetric operation, whereas the neat film is largely operating via the field effect. We propose that for higher-mobility materials, casting the active layer in a nanowire form may offer faster kinetics, enhanced volumetric capacitance, and possibly lower threshold voltage while maintaining desirable device performance.