Science  25 May 2012:
Vol. 336, Issue 6084, pp. 966

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  1. Indelible Ink

    The fossilized ink sac of a cephalopod—the group of tentacled invertebrates that includes today's octopi and squid—that lived 162 million years ago may still contain some ink pigment, according to a study online this week in the Proceedings of the National Academy of Sciences.


    Images of the 30-millimeter-long fossil taken with a scanning electron microscope reveal tiny spherical structures similar to structures in the ink of the modern-day cuttlefish (Sepia officinalis). But minerals could have replaced the original pigment particles, so the researchers tested samples of the fossil in a solution that breaks down melanin pigments.

    The reaction generated two substances found only in eumelanin, a brownish-black form of the pigment also found in the ink of today's cephalopods. The new findings may help scientists identify eumelanin or its remnants in other fossils, such as feathers or skin—which may, in turn, shed light on the role of pigments in ancient organisms.

  2. Solid Advance for Solar Cells

    Solar prices continue to drop slowly. But that trend could get a needed shove from an improvement to a 20-year-old solar technology that's never managed to catch on.

    Eighty percent of the market for solar cells is taken up by crystalline silicon cells, which convert about 20% of the energy in incoming sunlight into electricity. Most of the rest of the market comes from “thin film” cells made from metal alloys that are less efficient but also less expensive.

    Dye-sensitized solar cells (DSSCs), produced by a third technology, are the cheapest to make and are up to 12% efficient. But they rely on a liquid electrolyte to help move the electrical charges through the material—and liquid electrolytes can leak and lead to corrosion in other parts of the cell. Researchers have also tried solid electrolytes, which have so far been about only 6% efficient.

    But this week, researchers led by Mercouri Kanatzidis, a chemist at Northwestern University in Evanston, Illinois, report in Nature that they've developed a new solid electrolyte that gives DSSCs greater than 10% efficiency. That could be just what DSSCs need to make a splash in the market.