In contrast to traditional semiconductors, conjugated polymers provide ease of processing, low cost, physical flexibility and large area coverage. These active optoelectronic materials produce and harvest light efficiently in the visible spectrum. The same functions are required in the infrared for telecommunications (1,300-1,600 nm), thermal imaging (1,500 nm and beyond), biological imaging (transparent tissue windows at 800 nm and 1,100 nm), thermal photovoltaics (>1,900 nm), and solar cells (800-2,000 nm). Photoconductive polymer devices have yet to demonstrate sensitivity beyond approximately 800 nm (refs 2,3). Sensitizing conjugated polymers with infrared-active nanocrystal quantum dots provides a spectrally tunable means of accessing the infrared while maintaining the advantageous properties of polymers. Here we use such a nanocomposite approach in which PbS nanocrystals tuned by the quantum size effect sensitize the conjugated polymer poly[2-methoxy-5-(2'-ethylhexyloxy-p-phenylenevinylene)] (MEH-PPV) into the infrared. We achieve, in a solution-processed device and with sensitivity far beyond 800 nm, harvesting of infrared-photogenerated carriers and the demonstration of an infrared photovoltaic effect. We also make use of the wavelength tunability afforded by the nanocrystals to show photocurrent spectra tailored to three different regions of the infrared spectrum.

Ionic liquids (ILs) are liquids consisting entirely of ions and can be further defined as molten salts having melting points lower than 100 °C. One of the most important research areas for IL utilization is undoubtedly their energy application, especially for energy storage and conversion materials and devices, because there is a continuously increasing demand for clean and sustainable energy. In this article, various application of ILs are reviewed by focusing on their use as electrolyte materials for Li/Na ion batteries, Li-sulfur batteries, Li-oxygen batteries, and nonhumidified fuel cells and as carbon precursors for electrode catalysts of fuel cells and electrode materials for batteries and supercapacitors. Due to their characteristic properties such as nonvolatility, high thermal stability, and high ionic conductivity, ILs appear to meet the rigorous demands/criteria of these various applications. However, for further development, specific applications for which these characteristic properties become unique (i.e., not easily achieved by other materials) must be explored. Thus, through strong demands for research and consideration of ILs unique properties, we will be able to identify indispensable applications for ILs.

Ionic liquids (ILs) have been widely investigated as novel solvents, electrolytes, and soft functional materials. Nevertheless, the widespread applications of ILs in most cases have been hampered by their liquid state. The confinement of ILs into nanoporous hosts is a simple but versatile strategy to overcome this problem. Nanoconfined ILs constitute a new class of composites with the intrinsic chemistries of ILs and the original functions of solid matrices. The interplay between these two components, particularly the confinement effect and the interactions between ILs and pore walls, further endows ILs with significantly distinct physicochemical properties in the restricted space compared to the corresponding bulk systems. The aim of this article is to provide a comprehensive review of nanoconfined ILs. After a brief introduction of bulk ILs, the synthetic strategies and investigation methods for nanoconfined ILs are documented. The local structure and physicochemical properties of ILs in diverse porous hosts are summarized in the next sections. The final section highlights the potential applications of nanoconfined ILs in diverse fields, including catalysis, gas capture and separation, ionogels, supercapacitors, carbonization, and lubrication. Further research directions and perspectives on this topic are also provided in the conclusion.

lifetimes. In the past two decades, Li-ion batteries have dominated the rechargeable battery market for portable electronic devices such as smart phones, laptops, and other ubiquitous mobile technologies. However, conventional Li-ion batteries, which typically consist of a graphite anode and lithium transition-metal oxide cathode, have insuffi cient energy densities (theoretically, 350-400 W h kg −1 , practically, 100-220 W h kg −1 ) and are expensive. [ 1 ] These disadvantages severely limit their use in power-intensive applications such as long-range electrical vehicles and stationary energy storage. The demand for such new energy-storage systems has stimulated the development of compact and lightweight rechargeable batteries with superior performances, i.e., higher energy densities and longer cycling lifetimes. Li-S batteries, a "beyond Li-ion" technology, with cathodes that are made mainly of elemental sulfur, have a high theoretical specifi c capacity of 1672 mA h g −1 of active material. A sulfur cathode coupled with a Li metal anode is expected to give a theoretical energy density of 2600 W h kg −1 or 2800 W h L −1 when fully discharged, far greater than those of state-of-the-art Li-ion batteries. [ 2 ] In addition, sulfur is naturally abundant, inexpensive, and environmentally friendly, implying that Li-S batteries should be cheaper than currently available Li-ion batteries.There are, however, several serious problems with Li-S batteries, which have limited their commercial success: a) the reactant (sulfur) and product (Li 2 S) of the redox reaction are insoluble and electronically insulating; b) the Li metal anode is reactive and is prone to dendrite formation during cycling, resulting in safety hazards; c) the active materials undergo large volume expansion/contraction during discharge-charge, and this induces mechanical damage to the electrode; and d) the polysulfi de intermediates readily dissolve in the electrolyte and serve as a redox shuttle. Among these problems, the most critical are the dissolution, diffusion, and side reactions of soluble lithium polysulfi des in the electrolytes, as these processes cause problems such as irreversible loss of active materials from the cathode, low coulombic effi ciency, poor stability, rapid capacity fading, and high self-discharge. As shown in Figure 1 , the common Li-S battery architecture consists of a sulfur cathode (usually a S/C composite) and a Li metal anode The rapidly increasing demand for electrical and hybrid vehicles and stationary energy storage requires the development of "beyond Li-ion batteries" with high energy densities that exceed those of state-of-the-art Li-ion batteries. Li-S batteries, which have very high theoretical capacities and energy densities, are believed to be one of the most promising candidates. The sulfur-based electrochemical reaction requires novel electrolytes to replace the classical carbonate-based electrolyte systems inherited from Li-ion batteries because carbonates are incompatible with the intermediate polysulfi des ...

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A series of ionic liquids (ILs) based on nitrile-functionalized imidazolium, pyridinium, and quaternary ammonium as cations and chlorides and tetrafluoroborate, hexafluorophosphate, dicyanamide, and bis(trifluoromethanesulfonyl)imide as anions have been prepared and characterized. The physicochemical properties such as spectroscopic, thermal, solubility, surface, electrochemical, tribological, and toxic properties were comparatively studied. The results showed that the incorporation of a CN group to cations could result in remarkable changes in these properties. The reason resulting in such remarkable differences in the properties may be attributed to the conformational changes in the imidazolium groups caused by the interaction between the CN group with other neighboring cations or anions and the enhancement in hydrogen-bonding interactions due to the incorporation of a CN group.

Instead of traditional polymer precursors and complex procedures, easily prepared and widely obtainable nitrogen-containing protic ionic liquids and salts were explored as novel, small-molecule precursors to prepare carbon materials (CMs) via direct carbonization without other treatments. Depending on the precursor structure, the resultant CMs can be readily obtained with a relative yield of up to 95.3%, a high specific surface area of up to 1380 m(2)/g, or a high N content of up to 11.1 wt%, as well as a high degree of graphitization and high conductivity (even higher than that of graphite). One of the carbons, which possesses a high surface area and a high content of pyridinic N, exhibits excellent electrocatalytic activity toward the oxygen reduction reaction in an alkaline medium, as revealed by an onset potential, half-wave potential, and kinetic current density comparable to those of commercial 20 wt% Pt/C. These low-cost and versatile precursors are expected to be important building blocks for CMs.