In the latest issue of Science, researchers from Lund University in Sweden have shown how nanowires could pave the way for more efficient and cheaper solar cells.
"Our findings are the first to show that it really is possible to use nanowires to manufacture solar cells", says Magnus Borgstrm, a researcher in semiconductor physics and the principal author.
Research on solar cell nanowires is on the rise globally. Until now the unattained dream figure was ten per cent efficiency but now Dr Borgstrm and his colleagues are able to report an efficiency of 13.8 per cent.
The nanowires are made of the semiconductor material indium phosphide and work like antennae that absorb sunlight and generate power. The nanowires are assembled on surfaces of one square millimetre that each house four million nanowires. A nanowire solar cell can produce an effect per active surface unit several times greater than today's silicon cells.
Nanowire solar cells have not yet made it beyond the laboratory, but the plan is that the technology could be used in large solar power plants in sunny regions such as the south-western USA, southern Spain and Africa.
The Lund researchers have now managed to identify the ideal diameter of the nanowires and how to synthesise them. "The right size is essential for the nanowires to absorb as many photons as possible. If they are just a few tenths of a nanometre too small their function is significantly impaired", explains Magnus Borgstrm.
The silicon solar cells that are used to supply electricity for domestic use are relatively cheap, but inefficient because they are only able to utilise a limited part of the effect of the sunlight. The reason is that one single material can only absorb part of the spectrum of the light.
Research carried out alongside that on nanowire technology therefore aims to combine different types of semiconductor material to make efficient use of a broa
|Contact: Magnus Borgstrm |