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 silicon-based panels could begin in 2018.
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 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. Though conventional solar cells are still more efficient at about 25 percent, they’ve been stuck at that level for about 15 years, according to the World Economic Forum.
“All of a sudden you got about 10,000 researchers switching over to this field overnight,” Green said.
Perovskite cells could one day be placed on top of cars, windows, and walls. Oxford Photovoltaics Ltd., 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 8.1 million pounds ($10 million) of additional funding from investors including Statoil ASA.
“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.”
Challenges remain. For one, researchers must still come up with a way to ensure the material remains stable outdoors for long periods of time. Methods for painting the material on large surfaces must also be improved, said Masanori Iida, an official at the technology and design sector at Panasonic. “It is difficult to continuously make the coating even,” Iida said by email.
Oxford PV is targeting a high-speed production concept — the manufacture of cells at 3,200 substrates an hour — to sharpen the technology’s commercial pitch. But only to sell it on. Interestingly, the company wants to design cells for customers — the major module makers — rather than trying to manufacture and sell its own modules.
A first pilot line should be turning out Oxford PV perovskite-silicon cells “in the 2017-18 time frame”, says Case. “We’re really getting there.”
Another perovskite solar company Dyesol
Dyesol chief technology officer Damion Milliken tells Recharge. “But the development of this technology has really intensified in recent times: what was evolutionary for many years has become revolutionary. It’s come as far in the last 18 months as it took [the sector] to advance it in the last decade.”
For Dyesol, which started life as a dye-sensitised PV specialist, 2015 tells the tale of perovskite’s changing fortunes.
A distribution deal for its perovskite solar cell (PSC) with Tata Steel and technical tie-up with semiconductor outfit Cristal in the UK, along with a commercialisation agreement with Nesli DSC in Turkey, have put the company in a position to scale-up its “small module” prototype to a 1.2 metre x 0.6 metre demonstrator by early next year.
If all goes to plan, a piloting stage in which “around 20,000 metres of our PSC could be carved up for ‘demonstrator farms’” will be under way by 2018-19, “hopefully in Australia”, says Milliken.
“You don’t know if a technology has legs until you try to turn it into a product,” he explains. “Our first module we’d like to have been bigger, but it is a credible, meaningful size. Assuming we get the kind of power outputs we are expecting, we’ll quickly move on to prove the technology at array size and get the automated manufacturing going.”
The Dyesol technology — which layers a hybrid organic-inorganic halide-based perovskite light absorber and nanoporous titanium oxide — is targeted to reach a “highly competitive” levelised cost of energy (LCoE) of A$0.09-0.12 ($0.06-0.09) per watt.
Dyesol is concentrating on “solution coating” techniques to get away from mechanical and vapour-phase manufacturing processes, says Milliken. “It is definitely a challenge to uniformly process those large areas we desire to — but works out rather well once you get your head around it — whether it is washing, coating, printing, it’s all solution-based in the end.”