Idaho National Laboratory (INL) reports that research conducted in conjunction with partners at Microcontinuum Inc. (Cambridge, MA) and Patrick Pinhero of the University of Missouri is promising a method for developing cheap solar energy technology that could be imprinted on flexible materials and still draw energy after the sun has set.

The technology uses a special manufacturing process to stamp tiny square spirals, or “nanoantennas”, of conduction metal onto a sheet of plastic and the team estimates individual nanoantennas can absorb close to 80 percent of the available energy in comparison to current commercial solar panels which usually transform less that 20 percent of the usable energy that strikes them into electricity – this is even more impressive than the 30 per cent conversion rate offered by the recently discussed development of nano flakes.

Due to their size – each interlocking spiral nanoantenna is as wide as 1/25 the diameter of a human hair - the nanoantennas absorb energy in the infrared part of the spectrum, just outside the range of what is visible to the eye. Since the sun radiates a lot of infrared energy, some of which is soaked up by the earth and later released as radiation for hours after sunset, nanoantennas can take in energy from both sunlight and the earth’s heat, with higher efficiency than conventional solar cells. The new approach, which garnered two 2007 Nano50 awards, was made possible by the boom in nanotechnology, but finding an efficient way to stamp out arrays of atom-scale spirals took a number of years.

The INL team says that the antennas might one day be produced like foil or plastic wrap on roll-to-roll machinery and so far they have demonstrated the imprinting process with six-inch circular stamps, each holding more than 10 million antennas.

Article taken from gizmag