Company considers nanowire to be used in photovoltaic cells

Conventional solar cells are made of slabs of crystalline silicon — where a greater thickness allows better light absorption but presents difficulties for electrons trying to escape and create charge.

This trade-off is largely overcome with nanowires, since their length maximises absorption, but their nanoscale width permits a much freer movement and collection of electrons.

‘They have a so-called direct band gap, which means their absorption coefficient is so much higher than that of silicon,’ said Lars Samuelson, chief scientific officer and co-founder of Sol Voltaics. ’So where you need 100 microns of silicon to absorb all the photons, you need just a couple of microns to absorb all the photons [with nanowires], so you can have very thin layers and multiple layers.’

While the potential of nanowires in PVs has been recognised for the better part of a decade, they have proved difficult to produce, requiring expensive reactors. Now Sol Voltaics believes it has found a solution to create nanowires that can be stored as a dry powder or liquid for later use by customers.