Yvonne Carts-Powell

Manipulating electrical domains for better solar

In beautiful, Science, technology, writing on September 16, 2011 at 10:19 am

This is a beautiful piece of work.

When light shines on the surface of bismuth ferrite, it generates a voltage that is higher than the electronic bandgap. This is bizarre — the usual model for photovoltaics assume that the bandgap determines the possible voltage.

Bismuch ferrite also contains a bunch of small areas with alternating electrical polarity. Trying to figure out what is going on in the material in bulk is messy, since it would involve disambiguating effects from all those microscopic domains.

So instead, the researchers grew thin films — and not only that, but they managed to control the growth of domains so that they had a series of stripes with regularly alternating domains. No mean trick.

Once the domain structure was under control, the group was able to figure out how and why it generates such high voltages when exposed to light.

That is pretty interesting. But even more interesting is the idea that other materials, with the domains arranged in this way, should also kick up high photo-induced voltages. Fantastic!

For more, see the article I wrote for Optics & Photonics News:
Bismuth Ferrite Domains May Improve Solar Cells.

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