Muck and Mystery
   Loitering With Intent
blog - at - crumbtrail.org
April 08, 2009
Stone Tools

Or perhaps bone tools is a better characterization.

"Dye-sensitized solar cells already exist," Rorrer said. "What's different in our approach are the steps we take to make these devices, and the potential improvements they offer."

The new system is based on living diatoms, which are extremely small, single-celled algae, which already have shells with the nanostructure that is needed. They are allowed to settle on a transparent conductive glass surface, and then the living organic material is removed, leaving behind the tiny skeletons of the diatoms to form a template.

A biological agent is then used to precipitate soluble titanium into very tiny "nanoparticles" of titanium dioxide, creating a thin film that acts as the semiconductor for the dye-sensitized solar cell device. Steps that had been difficult to accomplish with conventional methods have been made easy through the use of these natural biological systems, using simple and inexpensive materials.

"Conventional thin-film, photo-synthesizing dyes also take photons from sunlight and transfer it to titanium dioxide, creating electricity," Rorrer said. "But in this system the photons bounce around more inside the pores of the diatom shell, making it more efficient."

The physics of this process, Rorrer said, are not fully understood – but it clearly works. More so than materials in a simple flat layer, the tiny holes in diatom shells appear to increase the interaction between photons and the dye to promote the conversion of light to electricity, and improve energy production in the process.

The claim is that this system can potentially triple the output of existing methods. Aharonov-Bohm nano rings come to mind.
Posted by back40 at 06:27 PM | Energy

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