Writing in the journal Nature Materials, materials scientists Michael Kelzenberg and Harry Atwater from Caltech discuss vertical silicon strings, or wires (“like blades of grass”), that could eventually work as cheap and highly effective solar collectors to generate electricity.

The original article, though almost incomprehensible to a layman, suggests that these Si (silicone) wire arrays are a promising architecture for solar-energy harvesting in that they are able to absorb sunlight over a wide range of wavelengths while still using only a “modest” fraction of the surface area.

In the demonstration, Kelzenberg and his associates showed that Si wires occupying less than 5 percent (by area) could achieve up to 96 percent absorption rates, or 85 percent of (above bandgap) direct sunlight, including near-infrared absorption that allowed the arrays to escape a previously-established absorption limit for the same amount of Si material.

This means the cells’ absorption rate was comparable to that of conventional solar cells, and their energy conversion rates as good as the best conventional solar cells, and better than thin-film.

The Si wires use 1/100 the amount of silicone of traditional solar cells, and could provide increased solar efficiency via an optical concentration rate of 20 times that of conventional silicone configurations.

Kelzenberg talks about using the Si wire principal to make thin-film solar – an idea no doubt arising out of the researcher’s experiments embedding the Si wires in a clear, silicone plastic called polydimethylsiloxane (also used in contact lenses, shampoo and lubricating oils for high-heat engines).

The researchers added efficiency by later incorporating aluminum oxide nanoparticles, which “scattered” incoming light and caused it to reach more of the microwires. This made the Si wire arrays as efficient as some solar panels now being used on roofs, and researchers speculated that a matrix made out of such wire could be woven into cloth.

Some saw, in effect, curtains, or drapes. Being a child of the sixties, I saw the ubiquitous beaded curtains of my youth. Silly, of course, given the fact that the wires, or rods, are about 100 times smaller than a human hair.

However they might be used, it would mean a new generation of truly environmentally-friendly fabrics, which could send electricity to the house’s junction box to supplant electricity delivered from the utility companies via coal-fired generation plants.

The wire or string styling is also reminiscent of the tubular solar panels manufactured by Solyndra, whose cylindrical shape makes them more effective at capturing solar insolation not merely from the “top”, but from the sides, and even from the bottom, since the tubular panels are mounted about a foot to 18 inches above the surface of the roof on white, “cool roof” membranes that reflect light onto the undersides of the tubes.