Nanoparticles for Solar Energy Conversion
from the every-nanoparticle-under-the-sun dept.
Gina Miller writes "Nanoparticles Used In Solar Energy Conversion reports that professor of chemistry David Kelley at Kansas State University has developed a gallium selenide nanoparticle of just the right size to use in solar cells. The spectrum of light absorbed changes with the size of the nanoparticle. 'Kelley is developing nanoparticles that are just the right size for solar cells — they can absorb all visible light but nothing from the invisible light at the red end of the spectrum, which would reduce voltage.'"
"According to Kelley, 'The correct-sized nanoparticles look dark red to black. There is an optimum size and that's what you want to shoot for.' This would be a dramatic difference from the solar cells of today which are constructed of expensive and often impure silicon. An impurity in a crystal can make it ineffective as a solar cell, but with nanoparticles most of the particles will have no impurity so most nanocrystals will work. Kelley hopes his work with gallium selenide will lay the foundation for work with indium selenide, which has especially great potential for nanoparticle solar cells. Kelley's project is funded by the U.S. Department of Energy's Solar Photochemistry Program in Basic Energy Sciences."
For other nanotechnological approaches to solar cells, see Nanodot posts of March 30 2002 and April 20 2002.
August 16th, 2002 at 2:52 AM
A questionable strategy
I'm not sure I buy this. Neither gallium selenide nor indium selenide would be inexpensive materials on which to base bulk solar cells. In addition, one doesn't want to throw away the IR photons, one simply wants to stack them so the lower voltages add to the higher voltages provided by the visible photons. This is the basis behind thermophotovoltaic cells that are now being stacked with normal visible cells. The efficiencies claimed for these cells can be very high (over 35-40+%). To get higher efficiencies one needs to have a better strategy for doing something useful with the UV photons. They have the highest energy but have the nasty property of being able to break covalent bonds contributing to the degradation of the solar cells.
August 27th, 2002 at 10:49 AM
Re:A questionable strategy
Talking about selenide and other materials as a type of nanotech is kind of curious to me. I thought nanotechnology would be in the form of molecular machines that perform functions at the molecular level. This just looks like chemicals interacting with other materials. How soon do you think research will actually produce molecular machines that will be used in the workplace, whether it be engineering or some other field. -wi