Giovannitti Alexander, Sbircea Dan-Tiberiu, Inal Sahika, Nielsen Christian B, Bandiello Enrico, Hanifi David A, Sessolo Michele, Malliaras George G, McCulloch Iain, Rivnay Jonathan
Department of Chemistry and Centre for Plastic Electronics, Imperial College London, London SW7 2AZ, United Kingdom.
Department of Bioelectronics, École Nationale Supérieure des Mines de Saint-Etienne, Centre Microélectronique de Provence (CMP-EMSE), Microelectronique et Objects Communicants, 13541 Gardanne, France; Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology (KAUST) Thuwal, 23955-6900, Saudi Arabia.
Proc Natl Acad Sci U S A. 2016 Oct 25;113(43):12017-12022. doi: 10.1073/pnas.1608780113. Epub 2016 Oct 10.
Electrolyte-gated organic transistors offer low bias operation facilitated by direct contact of the transistor channel with an electrolyte. Their operation mode is generally defined by the dimensionality of charge transport, where a field-effect transistor allows for electrostatic charge accumulation at the electrolyte/semiconductor interface, whereas an organic electrochemical transistor (OECT) facilitates penetration of ions into the bulk of the channel, considered a slow process, leading to volumetric doping and electronic transport. Conducting polymer OECTs allow for fast switching and high currents through incorporation of excess, hygroscopic ionic phases, but operate in depletion mode. Here, we show that the use of glycolated side chains on a thiophene backbone can result in accumulation mode OECTs with high currents, transconductance, and sharp subthreshold switching, while maintaining fast switching speeds. Compared with alkylated analogs of the same backbone, the triethylene glycol side chains shift the mode of operation of aqueous electrolyte-gated transistors from interfacial to bulk doping/transport and show complete and reversible electrochromism and high volumetric capacitance at low operating biases. We propose that the glycol side chains facilitate hydration and ion penetration, without compromising electronic mobility, and suggest that this synthetic approach can be used to guide the design of organic mixed conductors.
电解质门控有机晶体管通过晶体管沟道与电解质的直接接触实现低偏置操作。它们的操作模式通常由电荷传输的维度定义，其中场效应晶体管允许在电解质/半导体界面处进行静电荷积累，而有机电化学晶体管（OECT）则促进离子渗透到沟道主体中，这被认为是一个缓慢的过程，会导致体掺杂和电子传输。导电聚合物OECT通过引入过量的吸湿离子相实现快速开关和高电流，但工作在耗尽模式。在此，我们表明在噻吩主链上使用乙二醇化侧链可以产生具有高电流、跨导和尖锐亚阈值开关的积累模式OECT，同时保持快速开关速度。与相同主链的烷基化类似物相比，三甘醇侧链将水性电解质门控晶体管的操作模式从界面掺杂/传输转变为体掺杂/传输，并在低操作偏置下显示出完全可逆的电致变色和高体电容。我们认为乙二醇侧链促进水合作用和离子渗透，而不损害电子迁移率，并表明这种合成方法可用于指导有机混合导体的设计。
