A step closer to solar cells-Dye sensitized solar cells

Science 4 November 2011:
Vol. 334 no. 6056 pp. 629-634
DOI: 10.1126/science.1209688

RESEARCH ARTICLE

Porphyrin-Sensitized Solar Cells with Cobalt (II/III)–Based Redox Electrolyte Exceed 12 Percent Efficiency

ABSTRACT

The iodide/triiodide redox shuttle has limited the efficiencies accessible in dye-sensitized solar cells. Here, we report mesoscopic solar cells that incorporate a Co^(II/III)tris(bipyridyl)–based redox electrolyte in conjunction with a custom synthesized donor-π-bridge-acceptor zinc porphyrin dye as sensitizer (designated YD2-o-C8). The specific molecular design of YD2-o-C8 greatly retards the rate of interfacial back electron transfer from the conduction band of the nanocrystalline titanium dioxide film to the oxidized cobalt mediator, which enables attainment of strikingly high photovoltages approaching 1 volt. Because the YD2-o-C8 porphyrin harvests sunlight across the visible spectrum, large photocurrents are generated. Cosensitization of YD2-o-C8 with another organic dye further enhances the performance of the device, leading to a measured power conversion efficiency of 12.3% under simulated air mass 1.5 global sunlight.

Rapid Identification of Bacteria with a Disposable Colorimetric Sensing Array

James R. Carey*†, Kenneth S. Suslick*‡, Keren I. Hulkower‡, James A. Imlay§, Karin R. C. Imlay§, Crystal K. Ingison‡, Jennifer B. Ponder‡, Avijit Sen‡, and Aaron E. Wittrig‡

J. Am. Chem. Soc., 2011, 133 (19), pp 7571–7576

Rapid identification of both species and even specific strains of human pathogenic bacteria grown on standard agar has been achieved from the volatiles they produce using a disposable colorimetric sensor array in a Petri dish imaged with an inexpensive scanner. All 10 strains of bacteria tested, including Enterococcus faecalis and Staphylococcus aureus and their antibiotic-resistant forms, were identified with 98.8% accuracy within 10 h, a clinically important time frame. Furthermore, the colorimetric sensor arrays also proved useful as a simple research tool for the study of bacterial metabolism and as an easy method for the optimization of bacterial production of fine chemicals or other fermentation processes.

Can laser make the rain happen?

This video has an answer for you

Live 3D cell imaging

Figure 2: IML-SPIM super-resolution imaging of human mammary MCF10A cell spheroids expressing H2B-PAmCherry.

Live-cell 3D super-resolution imaging in thick biological samples

Nature Methods

(2011)

doi:10.1038/nmeth.1744

We demonstrate three-dimensional (3D) super-resolution live-cell imaging through thick specimens (50–150 μm), by coupling far-field individual molecule localization with selective plane illumination microscopy (SPIM). The improved signal-to-noise ratio of selective plane illumination allows nanometric localization of single molecules in thick scattering specimens without activating or exciting molecules outside the focal plane. We report 3D super-resolution imaging of cellular spheroids.

Photoreduction visualized

Photoreduction of ⁹⁹Tc Pertechnetate by Nanometer-Sized Metal Oxides: New Strategies for Formation and Sequestration of Low-Valent Technetium

Benjamin P. Burton-Pye, Ivana Radivojevic, Donna McGregor, Israel M. Mbomekalle, Wayne W. Lukens, Jr., and Lynn C. Francesconi

Publication Date (Web): October 10, 2011 (Article)

DOI: 10.1021/ja2060929

DNA origami

DNA Origami Nanopatterning on Chemically Modified Graphene^†

Je Moon Yun¹,
Kyoung Nan Kim²,
Ju Young Kim¹,
Dong Ok Shin¹,
Won Jun Lee¹,
Sun Hwa Lee¹,
Prof. Marya Lieberman^2,*,
Prof. Sang Ouk Kim^1,*

Article first published online: 27 OCT 2011

DOI: 10.1002/anie.201106198

Nanoscale folding of DNA: Taking advantage of facile solution processing, pattern formation under light irradiation, and ready chemical modification of graphene oxide, various patterned films of chemically modified graphene were prepared and employed for spatial patterning of DNA origami structures (see picture). The patterning of DNA origami structures required highly selective adsorption on graphene oxide surfaces.