We demonstrate high-performance polymer solar cells using the plasmonic effect of multipositional silica-coated silver nanoparticles. The location of the nanoparticles is critical for increasing light absorption and scattering via enhanced electric field distribution. The device incorporating nanoparticles between the hole transport layer and the active layer achieves a power conversion efficiency of 8.92% with an external quantum efficiency of 81.5%. These device efficiencies are the highest values reported to date for plasmonic polymer solar cells using metal nanoparticles.

A novel architecture consisting of Si nanowires internally grown from porous graphite is synthesized by etching of graphite with a lamellar structure via a VLS (vapor-liquid-solid) process. This strategy gives the high electrode density of 1.5 g/cm(3), which is comparable with practical anode of the Li-ion battery. Our product demonstrates a high volumetric capacity density of 1363 mAh/cm(3) with 91% Coulombic efficiency and high rate capability of 568 mAh/cm(3) even at a 5C rate. This good electrochemical performance allows porous graphite to offer free space to accommodate the volume change of Si nanowires during cycling and the electron transport to efficiently be improved between active materials.

End-group cross-linkable sulfonated poly(arylene ether) polymer (E-SFQK) was synthesized via direct polymerization of potassium 2,5-dihydroxybenzenesulfonate (SHQ) and decafluorobiphenyl (DFBP), followed by a reaction with ethynylphenol (EP). The cross-linking reaction of the ethynyl end group of E-SFQK was performed at 250 °C. After cross-linking, proton conductivity, water uptake, and swelling ratio of cross-linked membrane decreased from 0.16 (noncross-linked membrane) to 0.13 S/cm, from 86% to 42%, and from 31% to 13%, respectively. The effect of cross-linking time on proton conductivity, water uptake, and swelling ratio were also investigated. Methanol permeability of cross-linked membrane was compared with Nafion 117 due to solubility of noncross-linked membranes in methanol. The cross-linked membrane performed better, with a methanol permeability of 88 × 10 -8 cm 2 /s, as compared with 154 × 10 -8 cm 2 /s for Nafion 117. The cross-linked membrane also exhibited improved chemical resistance and oxidative stability from solubility and Fenton's tests. In order to study morphological changes of cross-linked and noncross-linked membranes, hydrophilic domain sizes from an AFM phase image were evaluated. These results showed that the sizes of hydrophilic domains of the crosslinked membrane (5-20 nm) are much smaller than those of noncross-linked membrane (20-50 nm).

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We demonstrate a simple route for preparing Si/SiO(x) urchin-like structures in which Si/SiO(x) core-shell nanocoils protruded out from the surface of bulk Si, via high-temperature annealing of Pt-decorated Si powders. The carbon-coated urchin-like anodes with micro- and nanostructured composite exhibit a significantly improved electrochemical performance with a high specific capacity of 1600 mAh/g and a superior cycling performance of 70 cycles at a rate of 0.2 C due to the nanocoil conformation and SiO(x) buffer layer. More importantly, the composite results in a significantly enhanced the volumetric capacity with ∼3780 mAh/cc, compared to bulk Si (∼2720 mAh/cc) after fully lithiation to 0 V.

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Coking is a major cause of performance degradation of Ni-based anodes in solid oxide fuel cells (SOFCs) powered by carbon-containing fuels. While modification of Ni surfaces using a thin coating of BaO, BaZr 0.9 Y 0.1 O 3−d (BZY), and BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3−d (BZCYYb) was reported to alleviate the problem, the mechanism is yet to be understood. In this study, in situ Raman spectroscopy and surface enhanced Raman spectroscopy (SERS) are used to probe the surface chemistry of BaO, BZY, and BZCYYb. Analyses of the time-resolved spectral features of C−C bonds, −OH groups, and −CO 3 groups reveal the interactions between surface functional groups and gas species (hydrocarbon, water steam, and CO 2 ). While the switching from −OH to −CO 3 groups is irreversible on BaO surfaces, it becomes reversible on both BZY and BZCYYb surfaces. Although the −OH mediated carbon removal is observed on the surfaces of all three catalysts, the −CO 3 is found effective for carbon removal only on the BZCYYb surface.

We demonstrate a simple method for the fabrication of rough silicon surfaces with micro- and nanostructures, which exhibited superhydrophobic behaviors. Hierarchically rough silicon surfaces were prepared by copper (Cu)-assisted chemical etching process where Cu nanoparticles having particle size of 10-30 nm were deposited on silicon surface, depending on the period of time of electroless Cu plating. Surface roughness was controlled by both the size of Cu nanoparticles and etching conditions. As-synthesized rough silicon surfaces showed water contact angles ranging from 93° to 149°. Moreover, the hierarchically rough silicon surfaces were chemically modified by spin-coating of a thin layer of Teflon precursor with low surface energy. And thus it exhibited nonsticky and enhanced hydrophobic properties with extremely high contact angle of nearly 180°.