03.03.10

Inexpensive Solar Cell with Near Perfect Quantum Efficiency

March 3, 2010 :: Researchers at the DOE Energy Frontier Research Center (EFRC) led by the California Institute of Technology have demonstrated for the first time that the conventional light-trapping limit for absorbing materials can be surpassed. They have created a new type of flexible solar cell that enhances the absorption of sunlight and efficiently converts its photons into electrons using arrays of long, thin silicon wires embedded in a polymer substrate. The new silicon wire arrays created are able to convert between 90 and 100 percent of the photons they absorb into electrons, with near-perfect internal quantum efficiency. Since each silicon wire measures between 30 and 100 microns in length and only 1 micron in diameter, in terms of area or volume, just 2 percent of it is silicon, and remainder 98 percent is polymer, making the solar cells much cheaper to produce, possibly manufactured in a roll-to-roll process. Findings were reported in the advance online edition of the journal Nature Materials. The work was supported by BES and by BP.

Simulated radiation induced cascade event

Reference: Kelzenberg, M.D., Boettcher, S.W., Petykiewicz, J.A., Turner-Evans, D.B., Putnam, M.C., Warren, E.L., Spurgeon, J.M., Briggs, R.M., Lewis, N.S., and Atwater, H.A., “Enhanced absorption and carrier collection in Si wire arrays for photovoltaic applications”, Nature Materials, 9, 239-2441 (2010) [DOI:10.1038/nmat2635External link].
 
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