Nanoscale technology
Interesting tech developments in nanotech, nanostructured materials, etc.

Ken Novak's Weblog


daily link  Monday, September 15, 2003


Economist update on Nanosys nanorod solar cells:  "Japan's leading maker of building materials, Matsushita Electric Works in Osaka. MEW, which is famous for its resin moulding and processing technology, has joined forces with Nanosys, a start-up co-founded by Dr Alivisatos in Palo Alto, California. The partners plan to develop nanorod composite cells for the construction materials industry in Asia. Nanosys and MEW (a subsidiary of Matsushita Electric Industrial, the world's largest consumer electronics maker) hope to release commercial versions of the new solar cells by 2007. The plan is to incorporate the composite solar cells into decorative roofing tiles or sidings, says Stephen Empedocles, a co-founder and director of business development at Nanosys. .. Dr Alivisatos thinks that if he can get the nanorods to point in a single direction, rather than randomly, he can boost the composite's energy efficiency. If that can be increased to 10%, Nanosys will have the basics for producing solar cells that are easy to work with and cheap to make. In June, the National Science Foundation awarded Nanosys a research grant worth $850,000 to develop the nanocomposite solar cell further. "  4:39:24 PM  permalink  

More light than heat: "What is needed is a glass that lets in light but keeps out stifling heat. Such glasses exist but are generally considered a luxury .. One version consists of a thin layer of silver sandwiched between plates of ordinary glass. 

Writing in a recent issue of Applied Physics Letters, Stefan Schelm and Geoff Smith of the University of Technology in Sydney, Australia, suggest a handy solution to the problem. The window they have developed consists of a sheet of plastic, rather than silver, sandwiched between plates of glass. The plastic, a standard polyvinyl butyral laminate is doped with nanoparticles of lanthanum hexaboride. This substance was chosen because it absorbs infra-red radiation but very little visible light. Because infra-red wavelengths carry the bulk of the heat, this allows the plastic layer to filter out most of the heat.

The nanoparticles do not even have to be particularly pure. Any contaminants created during production are so small, and fortunately transparent, as not to matter. The doped plastic transmits only 5% of the infra-red light, even when the concentration of nanoparticles is as low as 0.02%. The only side-effect is that the glass has a very slight blue-green tinge. .. Mr Schelm did not just happen upon lanthanum hexaboride, but chose it after modelling how conducting nanoparticles absorb light. By adjusting the size of the nanoparticles, or perhaps choosing a slightly different material, Mr Schelm may eventually get rid of the blue-green tinge."  I wonder if this can be combined with concentrators and high-efficiency PVs -- like from spectrolabs, yielding >25% up to 400 suns -- to make PVs pay?

  4:33:56 PM  permalink  

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