Here we summarize recent progress in the development of electrolyte-gated transistors (EGTs) for organic and printed electronics. EGTs employ a high capacitance electrolyte as the gate insulator; the high capacitance increases drive current, lowers operating voltages, and enables new transistor architectures. Although the use of electrolytes in electronics is an old concept going back to the early days of the silicon transistor, new printable, fast-response polymer electrolytes are expanding the potential applications of EGTs in flexible, printed digital circuits, rollable displays, and conformal bioelectronic sensors. This report introduces the structure and operation mechanisms of EGTs and reviews key developments in electrolyte materials for use in printed electronics. The bulk of the article is devoted to electrical characterization of EGTs and emerging applications.
We report that CoNi2S4 nanosheet arrays exhibit ultrahigh specific capacitance of 2906 F g(-1) and areal capacitance of 6.39 F cm(-2) at a current density of 5 mA cm(-2), as well as good rate capability and cycling stability, and superior electrochemical performances with an energy density of 33.9 Wh kg(-1) at a power density of 409 W kg(-1) have been achieved in an assembled aqueous asymmetric supercapacitor. The CoNi2S4 nanosheet arrays were in situ grown on nickel foams by a facile two-step hydrothermal method. The formation mechanism of the CoNi2S4 nanosheet arrays was based on an anion-exchange reaction involving the pseudo Kirkendall effect. The two aqueous asymmetric supercapacitors in series using the CoNi2S4 nanosheet arrays as the positive electrodes can power four 3-mm-diameter red-light-emitting diodes. The outstanding supercapacitive performance of CoNi2S4 nanosheet arrays can be attributed to ravine-like nanosheet architectures with good mechanical and electrical contact, low crystallinity and good wettability without an annealing process, rich redox reactions, as well as high conductivity and transport rate for both electrolyte ions and electrons. Our results demonstrate that CoNi2S4 nanosheet arrays are promising electrode materials for supercapacitor applications.
Correlations among the molecular structure, crystal structure, electronic structure, and charge-carrier transport phenomena have been derived from six congeners (2–7) of rubrene (1). The congeners were synthesized via a three-step route from known 6,11-dichloro-5,12-tetracenedione. After crystallization, their packing structures were solved using single-crystal X-ray diffraction. Rubrenes 5–7 maintain the orthorhombic features of the parent rubrene (1) in their solid-state packing structures. Control of the packing structure in 5–7 provided the first series of systematically manipulated rubrenes that preserve the π-stacking motif of 1. Density functional theory calculations were performed at the B3LYP/6-31G(d,p) level of theory to evaluate the geometric and electronic structure of each derivative and reveal that key properties of rubrene (1) have been maintained. Intermolecular electronic couplings (transfer integrals) were calculated for each derivative to determine the propensity for charge-carrier transport. For rubrenes 5–7, evaluations of the transfer integrals and periodic electronic structures suggest these derivatives should exhibit transport characteristics equivalent to, or in some cases improved on, those of the parent rubrene (1), as well as the potential for ambipolar behavior. Single-crystal field-effect transistors were fabricated for 5–7, and these derivatives show ambipolar transport as predicted. Although device architecture has yet to be fully optimized, maximum hole (electron) mobilities of 1.54 (0.28) cm2 V–1 s–1 were measured for rubrene 5. This work lays a foundation to improve our understanding of charge-carrier transport phenomena in organic single-crystal semiconductors through the correlation of designed molecular and crystallographic changes to electronic and transport properties.
The angular and temperature dependence of the field-effect mobility are investigated for p-type DNTT single crystals in a vacuum-gap structure. Temperature-independent transport behavior and weak mobility anisotropy are observed, with the best mobility approaching 10 cm(2) V(-1) s(-1) . Structural characterization and simulation suggest exceptionally high-quality and high-purity crystals.
We report comprehensive electrical characterization of electrolyte-gated field-effect transistors (FETs) incorporating organic single crystals of rubrene and several types of high capacitance ionic liquids (ILs). The specific capacitance associated with the liquid gate is exceptionally large, in the range of 1–10 μF/cm2, which facilitates the operation of devices at gate voltages below one volt. Gate-induced hole densities in rubrene single crystals are therefore on the order of 1013 cm–2, as determined from displacement current measurements (DCM) and confirmed by AC impedance measurements. Importantly, we observe a pronounced maximum in channel conductance with all ionic liquid gates which we attribute to a carrier localization effect at the semiconductor/liquid interface. Effective carrier mobility is a nonmonotonic function of gate voltage and depends on the choice of the IL. By gating with a tris(pentafluoroethyl)trifluorophosphate (FAP) containing IL, maximum carrier mobility in rubrene can be enhanced up to 3.2 cm2 V–1 s–1 at room temperature. Extensive efforts have been made to maximize the charge densities accumulated in rubrene crystals. At lower temperatures, higher gate bias can be applied before device breakdown, and up to 6 × 1013 cm–2 carriers can be accumulated at the rubrene/IL interface (0.3 holes per rubrene molecule), which doubles the amount of accumulated charge achieved at room temperature.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.