Quantum-dot-sensitized solar cell with unprecedentedly high photocurrent.

The reported photocurrent density (J(SC)) of PbS quantum dot (QD)-sensitized solar cell was less than 19 mA/cm(2) despite the capability to generate 38 mA/cm(2), which results from inefficient electron injection and fast charge recombination. Here, we report on a PbS:Hg QD-sensitized solar cell with an unprecedentedly high J(SC) of 30 mA/cm(2). By Hg(2+) doping into PbS, J(SC) is almost doubled with improved stability. Femtosecond transient study confirms that the improved J(SC) is due to enhanced electron injection and suppressed charge recombination. EXAFS reveals that Pb-S bond is reinforced and structural disorder is reduced by interstitially incorporated Hg(2+), which is responsible for the enhanced electron injection, suppressed recombination and stability. Thanks to the extremely high J(SC), power conversion efficiency of 5.6% is demonstrated at one sun illumination.

Photochemical generation of a new, highly fluorescent compound from non-fluorescent resveratrol.

UV irradiation of trans-resveratrol leads to its photochemical transformation to a new, highly fluorescent compound, whose chemical structure was unambiguously identified. The new compound has large values of fluorescence quantum yield, Stokes' shift, and two-photon absorption cross section, which make it suitable for bio-imaging, multi-color labeling, and two-photon microscopy.

Full surface embedding of gold clusters on silicon nanowires for efficient capture and photothermal therapy of circulating tumor cells.

We report on rapid thermal chemical vapor deposition growth of silicon nanowires (Si NWs) that contain a high density of gold nanoclusters (Au NCs) with a uniform coverage over the entire length of the nanowire sidewalls. The Au NC-coated Si NWs with an antibody-coated surface obtain the unique capability to capture breast cancer cells at twice the highest efficiency currently achievable (~88% at 40 min cell incubation time) from a nanostructured substrate. We also found that irradiation of breast cancer cells captured on Au NC-coated Si NWs with a near-infrared light resulted in a high mortality rate of these cancer cells, raising a fine prospect for simultaneous capture and plasmonic photothermal therapy for circulating tumor cells.