Light in the darkness

There have been a number of intriguing developments in the news this week, notably a three-dimensional solar cell system that uses optical fibres to guide sunlight onto dye-sensitised solar cells.

There have been a number of intriguing developments in the news this week. In the cyberpunk, someone’s-been-reading-sci-fi again corner, we had NEC’s simultaneous translation lensless glasses, unveiled at a Tokyo technology show, which use a tiny projector to beam live subtitles to the wearer. The medical arena also threw up some interesting nuggets, particularly a nanoparticle-infused material for root canal treatment from the Fraunhofer Institute, and a laser-based imaging system from Johns Hopkins Medical School which could help surgeons locate brain tumours without the need for a biopsy. We were also quite struck by Michigan State University’s robot fish.

But it’s a development in solar power that caught our eye. Zhong Lin Wang of the Georgia Institute of Technology led a team which developed a three-dimensional solar cell system which uses optical fibres to guide sunlight onto dye-sensitised solar cells. The fibres also form the active part of the cell; zinc-oxide nanowires are grown on the surface of the fibre, and these are coated with the dye-sensitised material which converts light to electricity. Light bounces around inside the fibre, interacting with the nanowires on each reflection; according to Wang, this makes the system up to six times as efficient as a standard dye-sensitised cell.

This could be an important technology for building-integrated solar cells, because it would mean that you don’t need to use the surface of the building as a light-collecting area. Optical fibre bristles built into the walls and roof of the building would carry sunlight in to the converters themselves, which would be hidden away somewhere indoors.

The drawback is that this type of cell isn’t as efficient as conventional amorphous or monocrystalline silicon photovoltaics, but the use of optical fibres could eliminate a lot of the drawbacks of solar panels, extending solar power to applications where there just isn’t the room for a panel. Maybe the future’s bright after all.

Stuart Nathan
Special Projects Editor