A University of Oxford professor can boost efficiency of silicon solar panels by a third

Henry Snaith, a professor at the University of Oxford has found a way to boost the efficiency of solar panels

Henry Snaith claims he can boost the efficiency of commercial silicon solar panels by almost a third. Even better: he says he can do it for £1 per metre. The trick? Applying a thin film of a crystalline structure called perovskite.
"The best available silicon modules are still around 22 per cent efficient and cost around $85 [£60] per metre," explains Snaith, a physics professor at the University of Oxford. "This increases the cost by ten per cent for an increased output of up to 30 per cent."
 
Snaith has worked to increase the standalone efficiency of perovskite from four per cent to 20 per cent, the fastest ever efficiency increase in solar technology since its photovoltaic properties were first tested in 2009. The strength of perovskite is that its band gap - the range of the spectrum from which it absorbs energy - is adjustable, unlike the band gap of silicon, which is fixed at one electron volt.

"This is the same as infrared, so all the excess energy from the light that's at a higher energy is lost," explains Snaith, 38. By tuning the lab-grown perovskite crystals to a higher band gap for visible light and combining it with a silicon panel for infrared, Snaith's two-part solar cell splits the spectrum to absorb more energy. Such multi-bandwidth cells have been produced before, but the prohibitive cost of manufacture has restricted their use to small-scale, high-value applications such as aerospace.

Snaith aims to have the panels available in three years through his company, Oxford Photovoltaics. Founded in 2010, it is developing a production line with a £12.6 million funding round in 2015. The end goal, however, is to get rid of silicon panels completely.

"Perovskite is a better material," Snaith explains. "You need only half a micron of perovskite instead of 200 microns of silicon. It's easier to process, and it should be more efficient. We're close to a tipping point where conventional power becomes not just un-environmental, but economically unfeasible."