Solar cell sets efficiency record

Research sponsored by the American military has resulted in a high-performance solar cell that has smashed the previous record for efficiently converting the sun's rays into electricity.

The US Defence Advanced Research Projects Agency (DARPA) has part-funded the development of a Very High Efficiency Solar Cell (VHESC) with the eventual goal of producing affordable solar battery chargers to fit out troops.

At the moment, 20% of the weight of a soldier’s pack is made up of batteries which can power their equipment for three days.

A reliable, efficient solar cell could significantly reduce that weight.

The University of Delaware has teamed up with chemical company DuPont to produce a crystalline silicon solar cell with an efficiency of 42.8% from sunlight – over 2% higher than the previous record of 40.7%.

The success has led to the military authorising further funding, thought to be worth up to US$100 million over three years, to continue development of the cells.

The consortium’s goal is to create mass-produced solar cells that operate at 50%.

It is expected new high efficiency solar cells could be in production by 2010.

Previous high-efficiency cells have relied on lens up to a foot thick to concentrate the sun’s rays, making them impractical for powering hand-held gear.

The Delaware cell is much thinner – at about a centimetre thick.

While the immediate applications for the high-tech military environment are obvious, the research is expected to have wider civilian benefits in the longer term.

David Gibbs

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