Thin-film transistors (TFTs) are the fundamental building blocks for the rapidly growing field of macroelectronics. The use of plastic substrates is also increasing in importance owing to their light weight, flexibility, shock resistance and low cost. Current polycrystalline-Si TFT technology is difficult to implement on plastics because of the high process temperatures required. Amorphous-Si and organic semiconductor TFTs, which can be processed at lower temperatures, but are limited by poor carrier mobility. As a result, applications that require even modest computation, control or communication functions on plastics cannot be addressed by existing TFT technology. Alternative semiconductor materials that could form TFTs with performance comparable to or better than polycrystalline or single-crystal Si, and which can be processed at low temperatures over large-area plastic substrates, should not only improve the existing technologies, but also enable new applications in flexible, wearable and disposable electronics. Here we report the fabrication of TFTs using oriented Si nanowire thin films or CdS nanoribbons as semiconducting channels. We show that high-performance TFTs can be produced on various substrates, including plastics, using a low-temperature assembly process. Our approach is general to a broad range of materials including high-mobility materials (such as InAs or InP).

The specific ionic conductivity, dynamic viscosity, and electrochemical stability of several imidazolium salts are reported as neationic liquids and their solutions in several organic solvents. The temperature dependence of conductivity and viscosity are analyzed for 1‐ethyl‐3‐methylimidazolium false(EMI+false) and 1,2‐dimethyl‐3‐n‐propylimidazolium false(DMPI+false) salts, and the influence of theanions bis(trifluoromethylsulfonyl)imide false(Im−false) , bis(perfluoroethylsulfonyl)imide false(Beti−false) , hexafluoroarsenate false(AsF6−false) , hexafluorophosphate false(PF6−false) , and tetrafluoroborate false(BF4−false) on these properties are discussed. These imidazolium salts make possible electrolytes with high concentration (>3 M), high room temperature conductivity (up to 60 mS/cm), and a wide window of stability false(>4Vnormalat 20 μA/cm2false) . Differential scanning calorimetric results confirm a large glass phase for the ionic liquids, with substantial (>80°C) supercooling. Thermal gravimetric results indicate the imidazolium salts with Im− and Beti− anions to be thermally more stable than the lithium salt analogs. The Vogel‐Tammann‐Fulcher interpretation accurately describes the conductivity temperature dependence. © 1999 The Electrochemical Society. All rights reserved.

2normalMethyl‐normaltetrahydrofuranfalse(2normalMe‐THFfalse)/LiAsF6 and several diethyl ether false(DEEfalse)/LiAsF6‐normalbased electrolytes have been characterized for their usefulness in rechargeable normalLi/TiS2 cells. This characterization has involved extended room temperature cell cycling at various depths of discharge, evaluation of rate/capacity behavior of cells at 25° and −10°C, and storage of cells at 50°C for up to one month with subsequent cycling. The thermal stability of the electrolytes at 71°C was evaluated by storage experiments in sealed tubes, followed by product analysis. The performance of 2normalMe‐THF/LiAsF6 cells far surpassed the others. The present data further substantiate previous reports from this laboratory of the superior behavior of 2normalMe‐THF/LiAsF6 solutions in rechargeable Li cells. The DEE/LiAsF6‐normalbased electrolytes are too unstable thermally to be of practical use.

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JANUARY 1982 ABSTRACTA new class of aprotic organic electrolytes in which to cycle the lithium electrode has been developed. Blends of diethyl ether (DEE) and tetrahydrofuran (THF) incorporating LiAsF6 have been found to afford Li electrode cycling efficiencies in excess of 98%. In addition, specular deposits of up to 10 C/cm 2 may be plated from these systems. The kinetic stability of these blended electrolytes toward Li is thought to be due to the formation of a protective lithium ethoxide film.Our ongoing search for electrolytes suitable for use in ambient temperature secondary Li batteries has led us to investigate solutions of LiAsF6 in propylene carbonate (PC) (1), tetrahydrofuran (THF) (2), and 2-methyltetrahydrofuran (2-Me-THF) (3). Average cycling efficiencies for the Li electrode in these media are 84, 88, and 96%, respectively (1C Li/cm 2 at 5 mA/ cm2). In this paper, we elaborate on the discovery of a class of diethyl ether (DEE)-based electrolytes which afford cycling efficiencies in excess of 98% (4,5). Moreover, Li plate morphologies are so regular and dendrite free that they may be deemed specular in appearance.Electrolytes comprising DEE have found use in ambient temperature Li primary batteries (6). More recently, Higgens reported on the stability of purified DEE toward Li and found that 1M LiAsF6/DEE was stable for over one month at 71~ (7). To our knowledge, however, no reports of DEE-based electrolytes employed in secondary Li batteries have surfaced in the open literature.While a variety of cosolvents have been found to improve the conductivity of LiAsF6/DEE electrolyte without degrading Li cycling performance (5), the best electrolyte to date comprises a 90:10 v/v mixture of DEE and THF, 2.5M in LiAsF6. We refer to this mixture as . This paper also explores the variation of Li half-cell cycling efficiencies with LiAsF6 concentration and with the addition of asymmetric ether cosolvents. ExperimentalGeneral.--All purification procedures subsequent to distillation and the electrochemical experiments were conducted at ambient temperature under Ar atmosphere in a Vacuum-Atmospheres Corporation dry box equipped with a Model He-493 Dri-Train.