Spray-on solar cells getting closer to reality

Researchers working toward possibility of commercial application on cars, windows, walls

Imagine a future when solar cells can be sprayed or printed onto the windows of skyscrapers or atop sports utility vehicles — and at prices potentially far cheaper than today’s siliconbased panels.

It’s not as far-fetched it seems. Solar researchers and company executives think there’s a good chance the economics of the $42 billion industry will soon be disrupted by something called perovskites, a range of materials that can be used to harvest light when turned into a crystalline structure.

The hope is that perovskites, which can be mixed into liquid solutions and deposited on a range of surfaces, could play a crucial role in the expansion of solar energy applications with cells as efficient as those currently made with silicon. One British company aims to have a thin-film perovskite solar cell commercially available by the end of 2018.

“This is the front-runner of low-cost solar cell technologies,” said Hiroshi Segawa, a professor at the University of Tokyo who’s leading a five-year project funded by the Japanese government that groups together universities and companies such as Panasonic Corp. and Fujifilm Corp. to develop perovskite technology.

The buzz has grown, thanks to research showing perovskite can convert sunlight more efficiently than initially thought. The big breakthrough came in 2012 when the material’s conversion efficiency — the portion of sunlight that can be converted into electricity — rose above 10 percent for the first time.

Passing that threshold attracted the attention of researchers toiling away on different types of solar cells that were then yielding lower efficiency, according to Martin Green, a professor at the University of New South Wales who also studies perovskite.

The efficiency of perovskite cells has improved further — exceeding 20 percent in the lab — to reach a level that took silicon cells years to achieve.

The efficiency improvements keep coming. In December, engineers at Green’s University of New South Wales announced they achieved a record 12.1 percent efficiency rating on a cell measuring 16 square centimeters. That’s the highest efficiency on a largesize perovskite solar cell to date, according to the university’s website. Higher efficiency ratings have been reported on smaller surfaces.

The advances have raised the possibility that perovskite cells could one day be placed on top of cars, windows, and walls. Oxford Photovoltaics, a spin-off from the University of Oxford, says it’s developing thin-film perovskite solar cells able to be printed directly onto silicon solar cells. In December, Oxford PV said it got $10 million of additional funding from investors including Statoil.

“We expect to have a product that meets industry requirements by the end of 2017,” Frank Averdung, chief executive officer at Oxford PV said by email. “Adding some time for qualification, certification and production, our first product could be commercially available towards the end of 2018.”