"Discovery of a ‘Dark State’ Could Mean a Brighter Future for Solar Energy"

Using "organic plastic semiconductor material" a group led by  Xiaoyang Zhu is looking to double Solar Cell efficiency.

The maximum theoretical efficiency of the silicon solar cell in use today is approximately 31 percent, because much of the sun's energy hitting the cell is too high to be turned into usable electricity. That energy, in the form of "hot electrons," is instead lost as heat. Capturing hot electrons could potentially increase the efficiency of solar-to-electric power conversion to as high as 66 percent.

Source and full story at http://www.utexas.edu/news/2011/12/15/dark_state/