[Credit: Caltech/Michael Kelzenberg]
Using arrays of long, thin silicon wires embedded in a polymer substrate, a team of scientists from the California Institute of Technology (Caltech) has created a new type of flexible solar cell that enhances the absorption of sunlight and efficiently converts its photons into electrons. The solar cell does all this using only a fraction of the expensive semiconductor materials required by conventional solar cells.
* these solar cells have, for the first time, surpassed the conventional light-trapping limit for absorbing materials
* The silicon-wire arrays absorb up to 96 percent of incident sunlight at a single wavelength and 85 percent of total collectible sunlight
* the wires have a near-perfect internal quantum efficiency.
* Each wire measures between 30 and 100 microns in length and only 1 micron in diameter. "The entire thickness of the array is the length of the wire," notes Atwater. "But in terms of area or volume, just 2 percent of it is silicon, and 98 percent is polymer
