Dec 15 2009
Researchers of Boston College for the very first time have observed “hot electron” effect in a solar cell and the elusive charges have been successfully harvested with the usage of ultra-thin solar cells. This discovery can be utilized for the improvement of solar power efficiency.
Free electrons are generated in different energy states when light is captured in solar cells. The electrons should reach the bottom part of the conduction band for the charges to be captured. In this process a lot of energy is lost by the electrons that are highly energized. For a long time researchers have speculated on the benefits of exploiting the hot electrons for solar power generation through “3rd generation devices”. Hot electrons or hot carriers have also been found in semiconductors though they have been known to damage a device because of their high kinetic energy.
Michael J. Naughton, the Evelyn J. and Robert A. Ferris Professor of Physics at Boston College, stated that the team of researchers invented a mechanism to remove hot electrons just before they get cooled by using ultra-thin solar cells.
Krzysztof Kempa, Professor of Physics, remarked that the team succeeded in their research as they were focused in reducing the environment within which the electrons are able to escape. The size of the solar cell was reduced so that the hot electrons could be brought closer to the surface for easy collection. Kempa suggested that these hot electrons have to be captured in less than a picosecond.