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.

The extraordinary combination of high thermal stability, low volatility and the possibility of tailoring the physical and chemical properties of ionic liquids (ILs) by modifying their molecular features such as the length and nature of the cation lateral chains and the anion size and composition, has open the field of application of these green ordered fluids.

ILs have shown their ability to provide effective lubrication with very low friction coefficients and wear rates under conditions for which the currently used lubricating fluids fail. These conditions cover strategic technologies such as aerospace, microelectronics and nanotechnology applications.

At the present moment, there exist no liquid lubricants for high temperature, high vacuum and cryogenic conditions. We have determined the lubricating ability of ILs under extreme temperature conditions.

We have determined the conditions for the formation of tribocorrosion reaction products at metal-metal and metal-polymer interfaces. In the case of fluorine or phosphorus-containing imidazolium ionic liquids, formation of metallic fluorides and phosphates at the contact surfaces is the determining wear mechanism step.

The surface interactions of imidazolium room temperature ILs have been studied in a variety of materials in sliding contact under variable conditions, both as neat lubricants and as additives of conventional basestocks.

The ability of ILs molecules to interact with surfaces has also been explored in nanotechnology applications. It is well known that the use of ILs as solvents in the synthetic route, allows the control of size and shape of a variety of nanoparticles. We have developed new polymer/IL/nanoparticle nanocomposites where the size, morphology and distribution of the nanoparticles are controlled by surface interactions with IL molecules.

We will show that metallic and bimetallic nanoparticles solubilized in 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquids (IL) can be used as catalysts for a variety of oxidation and hydrogenation reactions. Nanoparticles were either directly synthesized in the IL or transferred to the IL from other solvents. Characterization was carried out by UV-Vis spectroscopy and transmission electron microscopy. Both the activity and selectivity of the hydrogenation reactions could be tuned by varying the composition of AuPd bimetallic nanoparticles. We will also show that the nanoparticle/IL catalysts can be recycled and then reused for further catalytic reactions with minimal loss in activity. In addition, new insights into the stabilization of nanoparticles in ionic liquids will be presented.

Room-temperature ionic liquids are utilized in a new CO2 capturing fuel cell. The cell is aimed at the efficient and cost effective removal of CO2 emitted from transportation related sources. The CO2 is captured from the atmosphere and is later converted into carbon free synthetic fuel such as methanol. In this study we optimized the operating conditions and the cell electrolytes. With ionic liquids such as 1-Butyl-1-methylpyrrolidinium dicyanamide, the extraction efficiencies increased to ∼20% while simultaneously making the capture process more robust. The ionic liquid approach is also compared to existing aqueous electrochemical CO2 concentration previously proposed by NASA for aerospace applications but with much lower efficiencies.

Many-body polarizable force field has been developed and validated for a wide class of ionic liquids. Classical molecular dynamics (MD) simulations have been performed on 29 ionic liquids. This presentation will focus on ability of developed force fields to predict condensed phase properties and on understanding the influence of many-body polarizable interactions on the ionic liquid structure and transport.