A collection of technologies termed social computing is driving a dramatic evolution of the Web, matching the dot-com era in growth, excitement, and investment. All of these share a high degree of community formation, user level content creation, and a variety of other characteristics. We provide an overview of social computing and identify salient characteristics. We argue that social computing holds tremendous disruptive potential in the business world and can significantly impact society, and outline possible changes in organized human action that could be brought about. Social computing can also have deleterious effects associated with it, including security issues. We suggest that social computing should be a priority for researchers and business leaders and illustrate the fundamental shifts in communication, computing, collaboration, and commerce brought about by this trend.

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Mesoporous SnO2 spheres of tunable particle size were synthesized for the first time by facile electrochemical anodization of tin foil in alkaline media. As the anodization process involves no sophisticated reactor or toxic chemicals, and proceeds continuously under ambient conditions, it provides an economic way of synthesizing nanostructured SnO2 on a large scale. Structural characterization indicates that these spherical particles consist of an agglomeration of SnO2 nanocrystals, resulting in a high internal surface area. This makes them a promising photoanode material for use in semiconductor-sensitized solar cells (SSCs). By using the successive ionic-layer adsorption and reaction method, a thin layer of CdSe was conformally coated on the surface of SnO2 nanocrystals, which were previously treated with aqueous TiCl4 solution. Efficient charge separation was observed by photoluminescence spectroscopy. After deposition of a ZnS passivation layer onto the CdSe light-harvesting layer, a power conversion efficiency of ∼1.91% was achieved in a regenerative photoelectrochemical cell. Factors dictating interfacial charge recombination and charge separation are discussed and compared to those in its molecular dye-sensitized counterpart. This study represents the first attempt so far of using mesoscopic SnO2 as a photoanode in a SSC device, and characterizing it under simulated AM 1.5, 100 mW cm−2 illumination. The results are a step toward development of highly efficient SSCs employing novel electron transport materials and sensitizers, such as infrared light absorbers PbS, CuInSe2, etc.

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The self-aggregation behavior of three amphiphilic graft copolymers, oligo(9,9-dihexyl)fluorence-graft-poly(ethylene oxide) (OHF-g-PEO), with different architectures was studied by dynamic and static light scattering (DLS and SLS) in combination with fluorescence spectroscopy and transmission electron microscopy (TEM). The formation of self-assembled polymeric micelles was confirmed by SLS and TEM. DLS and SLS analyses showed that the architecture of graft copolymers has a dramatic effect on critical aggregation concentration (CAC), micelle size distribution, apparent aggregation number (Nagg app), and apparent molecular weight of polymer aggregates (Mw,agg app). An architecture-dependent excimer emission, resulting from the pi-pi stacking of the oligofluorene backbones, was also observed from the photoluminescence spectra of the micelle aqueous solutions, which indicated a strong intermolecular interaction among the polymeric molecules. The excimer emission was further investigated by time-resolved fluorescence spectroscopy.

Indolo[2,3-a]carbazole-based heteroacenes containing thiadiazole units were synthesized. Compounds showed a sandwich herringbone packing in solid state with improved stability. The change in photophysical and electrochemical properties upon incorporation of an acceptor moiety (benzothiadazole) in a fused ring system was studied. The unsubstituted compound was electropolymerized to yield a stable polymer.

A new series of dithieno[3,2-b:2′,3′-d]pyrrole-incorporated oligomers was synthesized and characterized. The crystal structure, crystal packing, optical properties, electrochemical properties, and time-of-flight mobilities were investigated in detail. The oligomers are highly fluorescent in both solution and the solid state. The solution-state quantum yield of these new compounds ranged from 52 to 75%. Band gaps of these oligomers were found to be in the range of 2.5-2.8 eV. The surface morphology of the film was also characterized by atomic force microscopy. The material was found to be hole-transporting with a mobility on the order of 10 -6 cm 2 /(V s).