Is perovskite ready for primetime?
About 90 percent of today’s solar panels are made from silicon —but some researchers believe a new class of materials called perovskites could be on the brink of taking the industry by storm.
Perovskite-based solar technology is still several years from maturity, says Homer Antoniadis, global technology director of DuPont's solar business, but the technology is evolving rapidly. Perovskite cells leapt from 3.8 percent efficiency in 2009 to over 20 percent efficiency by the end of 2014, and experts say efficiency rates of 31 percent or higher are technologically feasible. That’s an enticing prospect for an industry that in the past 15 years has seen silicon PV cells’ efficiency increase just 0.6 percentage points, to a current ceiling of 25.6 percent.
Combined with perovskite’s low cost, increased PV-cell efficiency could make the solar industry genuinely cost competitive with the fossil fuel sector. Unlike silicon panels, which must be painstakingly grown in a furnace at temperatures of around 2,500 degrees Fahrenheit, manufacturing perovskite involves little more than mixing cheap chemicals such as ammonia, iodine, and lead, and leaving them to dry. “The perovskite ingredients are cheaper than ink,” says leading perovskite researcher Tsutomu Miyasaka.
An added bonus: perovskites can be formed in thin films, allowing them to be deployed in places undreamed of for silicon PV panels. Some researchers foresee a future in which spray-on perovskites could be incorporated into smartphone screens, or applied as a see-through laminate on walls and windows. Others hope to create “tandem”cells, in which a layer of perovskite is applied over a standard silicon cell to exploit the two materials' relative strengths at absorbing different parts of the light spectrum. That could lead to the production of solar panels that are up to 50 percent more efficient than existing cells, according to researchers at Stanford University.
Some major hurdles remain — including, most troublingly, the fact that perovskite degrades when exposed to light and air. That raises questions about the validity of efficiency data gleaned from prototype panels, says Keith Emery, a solar energy researcher with the National Renewable Energy Laboratory. It also calls into question claims that perovskite will dramatically bring down the cost of solar energy. “Until the stability problem is solved, you do not know how much it is going to cost you,” Emery says.
Companies to watch
* Australia’s Dyesol is working with a Turkish partner to manufacture perovskite-based panels that could be incorporated into buildings’ facades. Dyesol has agreed a $1.9 million contract to fund prototyping, and could begin mass production as early as 2018.
* Perovskite startup Oxford Photovoltaics recently raised £8 million ($12.26 million) from investors including the University of Oxford, MTI Partners, and Longwall Venture Partners. The firm plans to bring tandem perovskite-silicon solar cells to market by the end of 2015.
* Warsaw-based startup Saule Technologies was founded in 2014 by a Polish grad student who won a European Commission prize for perovskite research. The privately backed venture recently turned down financing that would have valued the company at around $13 million.
* Pittsburgh-based vacuum products specialist Kurt J. Lesker Co. has won praise from solar researchers for its Mini-SPECTROS vapor deposition system, a piece of lab equipment that can be used to layer perovskites in thin films compatible with existing silicon PV technologies.
Ben Whitford is the US correspondent for The Ecologist. He has written for the Guardian, Newsweek, Mother Jones, Slate, and many other publications.