formed gels and showed liquid crystalline structures at high concentrations. The absorption properties of poly(3-hexylthiophene) showed dramatic changes during gelation, which is an indication of strong intermolecular π-electronic coupling of the ordered self-assembled poly(3-hexylthiophene) gels. The effect of conformational transitions on the photovoltaic properties of solution-processed poly(3hexylthiophene)/fullerene blends has been studied in this Article. It is shown that the photovoltaic performance is strongly affected by gelation, which alters the morphology of the photoactive layer. Device optimization yields solar cells with a power conversion efficiency of 3.78% under standard test conditions (AM 1.5, 100 mW/cm 2 ).

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An LC source-degeneration negative-resistance cell of an LC VCO is investigated, which is capable of operating at millimeter-wave (MMW) range with low dc power consumption. Several negative-resistance cells in LC oscillators are also compared. The LC source-degenerated topology is demonstrated through a 114-GHz push-push fully integrated LC VCO implemented in TSMC 0.13-m CMOS process. With core power consumption of 8.4 mW, the tuning range at the fundamental port is 56.4-57.6 GHz and at the push-push port is 112.8-115.2 GHz. The measured phase noise at the fundamental port is 113.6 dBc/Hz at 10-MHz offset. This VCO is believed to have the best figure of merit among MMW VCOs using bulk CMOS processes.

[reaction: see text] This Mg-TiCl4-promoted CH2-transfer reaction of CH2Cl2 represents an extremely simple, practical, and efficient methylenation of a variety of ketones and aldehydes, especially in enolizable or sterically hindered ketones such as 2,2-dimethylcyclohexanone, camphor, and fenchone.

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Poly(3-hexylthiophene)(P3HT) with a microporous network structure was prepared from a 1% p-xylene solution by freeze-dry method. Scanning electron microscopy (SEM) showed P3HT molecules formed swollen gel-like structures with different extent of compactness depending on the length of the aggregation period. Absorption spectrum of this P3HT film showed a characteristic peak at 620 nm, which indicated a high degree of order between polymer chains. Photoluminescence (PL) of this highly ordered P3HT film appeared at 712 nm revealing large extent of p-p stacking between P3HT molecules in the freeze-dry film. Both absorption and photoluminescence results indicated that the original aggregated states of P3HT molecules in gel form had been preserved throughout the freeze-dry operation. X-ray diffraction of the annealed samples showed a strong characteristic peak for the side chain aggregation at 2y ¼ 5.1 , which proved that the freeze-dry film was with highly order structure. The interconnected and highly ordered P3HT film is used in the study of organic photovoltaics (OPV) after applying an n-type semiconductor to the surface of the dry porous fibers. A prototype OPV device with power conversion efficiency of 1.47% was prepared by this method.

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