As much as we would like it, solar energy still isn’t competitive with fossil fuels, mostly because one of the main materials used in their production is the incredibly expensive metal indium.

But that might change in the near future as Duke University researchers have found a way to replace indium with copper nanowires. And the nanowires will decrease the cost of touchscreens to boot.

Indium

The most efficient solar cells currently in use are thin-film photovoltaics. Most of these solar cells are made of a thin layer of copper indium gallium selenide (CIGS) on top of a layer of glass.

Although not much of the material is needed (it isn’t called thin-film for nothing), it is indium that makes such solar cells expensive since the metal goes for around $800 per kilogram.

It’s this same material that makes touchscreens in mobile phones and tablet PCs so expensive. They are made of indium tin oxide (ITO) which has another rather annoying property. It breaks easily, which obviously isn’t the best quality for a touchscreen.

Copper nanowires

The new copper nanowires, presented in Advanced Materials share all the useful properties of ITO and CIGS, like transparency and conductivity, but eliminate their drawbacks.

At $9 dollars per kilogram they are almost a hundred times cheaper than indium and at least a thousand times more resistant to breaking. In fact they are so resistant to it, they might be a good basis for foldable electronics. On top of that they are a lot easier and faster to produce.

So who needs more efficient solar cells when you can get cheaper ones? Well in fact for solar energy to beat fossil fuels we probably will need them, but at least this development has the potential to put solar energy and fossil fuels on par in cost.

© Jorn van Dooren | www.bitsofscience.org