Solar Panels that Can Work at Night? by Duncan Graham-Rowe, via NewScientist.com A new breed of electronic solar cells that harvests power from heat could double the output of conventional panels. SOLAR cells that work at night. It sounds like an oxymoron, but a new breed of nanoscale light-sensitive antennas could soon make this possible, heralding a novel form of renewable energy that avoids many of the problems that beset solar cells. The key to these new devices is their ability to harvest infrared (IR) radiation, says Steven Novack, one of the pioneers of the technology at the US Department of Energy’s Idaho National Laboratory in Idaho Falls. Nearly half of the available energy in the solar spectrum resides in the infrared band, and IR is re-emitted by the Earth’s surface after the sun has gone down, meaning that the antennas can even capture some energy during the night. Lab tests have already shown that, under ideal conditions, the antennas can collect 84 per cent of incoming photons. Novack’s team calculates that a complete system would have an overall efficiency of 46 per cent; the most efficient silicon solar cells are stalled at about 25 per cent. What’s more, while those ideal conditions are relatively narrowly constrained for silicon solar cells—if the sun is in the wrong position, light reflects off a silicon solar cell instead of being absorbed – the antennas absorb radiation at a variety of angles. If the antennas can be produced cheaply, the technology could prove to be truly disruptive, says Novack. Unlike photovoltaic cells, which use photons to liberate electrons, the new antennas resonate when hit by light waves, and that generates an alternating current that can be harnessed. To build an array that could capture both visible and infrared radiation, researchers envision multiple layers of antennas, with each layer tuned to a different optical frequency. Click here to read the rest of this article at NewScientists.com.

Solar Panels that Can Work at Night?

by Duncan Graham-Rowe, via NewScientist.com

A new breed of electronic solar cells that harvests power from heat could double the output of conventional panels. SOLAR cells that work at night. It sounds like an oxymoron, but a new breed of nanoscale light-sensitive antennas could soon make this possible, heralding a novel form of renewable energy that avoids many of the problems that beset solar cells.

The key to these new devices is their ability to harvest infrared (IR) radiation, says Steven Novack, one of the pioneers of the technology at the US Department of Energy’s Idaho National Laboratory in Idaho Falls. Nearly half of the available energy in the solar spectrum resides in the infrared band, and IR is re-emitted by the Earth’s surface after the sun has gone down, meaning that the antennas can even capture some energy during the night.

Lab tests have already shown that, under ideal conditions, the antennas can collect 84 per cent of incoming photons. Novack’s team calculates that a complete system would have an overall efficiency of 46 per cent; the most efficient silicon solar cells are stalled at about 25 per cent. What’s more, while those ideal conditions are relatively narrowly constrained for silicon solar cells—if the sun is in the wrong position,light reflects off a silicon solar cell instead of being absorbed – the antennas absorb radiation at a variety of angles. If the antennas can be produced cheaply, the technology could prove to be truly disruptive, says Novack.

Unlike photovoltaic cells, which use photons to liberate electrons, the new antennas resonate when hit by light waves, and that generates an alternating current that can be harnessed.

To build an array that could capture both visible and infrared radiation, researchers envision multiple layers of antennas, with each layer tuned to a different optical frequency.

Click here to read the rest of this article at NewScientists.com.