A novel atom-molecule conversion technique has been investigated. Ultracold 85Rb atoms sitting in a dc magnetic field near the 155 G Feshbach resonance are associated by applying a small sinusoidal oscillation to the magnetic field. There is resonant atom to molecule conversion when the modulation frequency closely matches the molecular binding energy. We observe that the atom to molecule conve...

Solar cells are one attractive method for harnessing inexhaustible clean energy from the sun. Organic photovoltaic technology is emerging as a potential competitor to silicon-based photovoltaic cells (PVCs), and their power conversion efficiencies (PCE) can now exceed 6%. Polymeric bulk-heterojunction (BHJ) PVCs, whose photoactive layer is composed of a blend of bicontinuous and interpenetratin...

Following the first report on dye-sensitized solar cells (DSCs) by Prof. Grätzel in 1991, thousands of papers have been published with the aim of making DSCs commercially viable (Fig. 1). They are attractive because of their low-cost materials and convenient fabrication by a non-vacuum, high-speed printing process. One of the key materials in DSCs is the sensitizer dye. Ruthenium-complex dyes a...

Vertical arrays of ZnO nanowires can decouple light absorption from carrier collection in PbS quantum dot solar cells and increase power conversion efficiencies by 35%. The resulting ordered bulk heterojunction devices achieve short-circuit current densities in excess of 20 mA cm(-2) and efficiencies of up to 4.9%.

Four-wave mixing is observed in a silicon W1 photonic crystal waveguide. The dispersion dependence of the idler conversion efficiency is measured and shown to be enhanced at wavelengths exhibiting slow group velocities. A 12-dB increase in the conversion efficiency is observed. Concurrently, a decrease in the conversion bandwidth is observed due to the increase in group velocity dispersion in t...

We demonstrate highly broad-band frequency conversion via four-wave mixing in silicon nanowaveguides. Through appropriate engineering of the waveguide dimensions, conversion bandwidths greater than 150 nm are achieved and peak conversion efficiencies of -9.6 dB are demonstrated. Furthermore, utilizing fourth-order dispersion, wave-length conversion across four telecommunication bands from 1477 ...

Recent advances in polymer solar cell (PSC) performance have resulted from compressing the bandgap to enhance the short-circuit current while lowering the highest occupied molecular orbital to increase the open-circuit voltage. Nevertheless, PSC power conversion efficiencies are still constrained by low fill factors, typically below 70%. Here, we report PSCs with exceptionally high fill factors...

The biological production of hydrogen from the fermentation of different substrates was examined in batch tests using heat-shocked mixed cultures with two techniques: an intermittent pressure release method (Owen method) and a continuous gas release method using a bubble measurement device (respirometric method). Under otherwise identical conditions, the respirometric method resulted in the pro...