Low-power and Fast-switching Organic Field-effect Transistors with Ionic Liquids

Abstract

We report high-mobility rubrene single-crystal field-effect transistors with ionic-liquid electrolytes used for gate dielectric layers. As the result of fast ionic diffusion to form electric double layers, their capacitances remain more than 10 μF/cm2 even at 0.1 MHz. With high carrier mobility of 1.2 cm2/Vs in the rubrene crystal, pronounced current amplification is achieved at the gate voltage of only 0.2 V, which is two orders of magnitude smaller than that necessary for organic thin-film transistors with dielectric gate insulators. The results demonstrate that the ionic-liquid/organic semiconductor interfaces are suited to realize low-power and fast-switching field-effect transistors without sacrificing carrier mobility in forming the solid/liquid interfaces.

Electric double-layer transistors: a review of recent progress

“…In 2011, Rolandi and coworkers first used the maleic-chitosan nanofibers to design a biopolymer Reproduced from [112] with permission from AIP Publishing LLC. Reproduced from [113] with permission from American Chemical Society Ionic liquids can maintain liquidity over a wide temperature and there is no redox reactions when ILs are exposed to the small potential differences [26] The absorption of water by IL could degrade the device properties and stability of EDLTs under ambient condition [23] Ionic liquids exhibit double-layer capacitances of 20-30 lF cm -2 and high-speed formation of the EDLs can be realized because of the existence of ILs and the rapid ionic diffusion of the ions [12,116] When high V G is applied, an electrochemical reaction in the ionic liquid can induce a large Faradaic leakage current flowed between the channel and the gate electrode [68] Because of large carrier accumulation induced by EDL, ionic liquid gating is the only way to achieve ambipolarity in some ambipolar materials such as MoS 2 [29], WSe 2 [37], WS 2 [117], and Bi 2 Te 3 [118] (as shown in Fig. 21), which cannot be obtained by conventional gating methods protonic FET, which can control and monitor the flow of protonic current in this nanostructured biocompatible solidstate device, offering opportunities for interfacing with living systems [129].…”

“…For example, in 2007, Weisheit et al reported a relatively large electricfield-induced modification of magnetism by forming EDL at FePt or FePd/electrolyte interface [11]. As the thickness of EDL is *1 nm [12], equal current value can be achieved with such a small gate voltage when the mobility of the carriers induced by the EDL is similar to that in the insulator/channel interface of conventional FETs. EDLTs have attracted a lot of research interests since much higher charge-carrier density can be accumulated near electric double layer.…”