By Katie Kramon
A team of Stanford researchers has collaborated with scientists at the Department of Energy’s National Renewable Energy Laboratory (NREL) to produce the first successful demonstration of peel-and-stick solar cells, which can be attached to almost any surface or object.
Qi Wang, an NREL scientist who has done extensive work with solar cells, first met Assistant Professor of Mechanical Engineering Xiaolin Zheng at a conference last year. The two decided to form a partnership after realizing that peel-and-stick technology developed at Stanford could be applied to solar cells.
The research team also included NREL research engineer William Nemeth, Dong Rip Kim, an assistant professor in the division of mechanical engineering at Hanyang University in Seoul, South Korea, and doctoral students Chi Hwan Lee and In Sun Cho.
According to Zheng, the ability to attach lighter and thinner solar cells to more surfaces and objects, “from cars to light posts,” will expand the energy source’s potential uses. The cells could even be affixed to items like backpacks that are too small to accommodate large and unwieldy solar panels.
While other researchers have previously made flexible solar cells, the team’s work is unique for the cells’ creation on a nickel-silicon wafer, from which the cells are then peeled off when dipped in water. The wafer can subsequently be reused to fabricate new solar cells.
After the cell is peeled from the wafer, it is exposed to heat for approximately 90 seconds before it can be stuck to any surface. This method preserves the integrity of the cells, which maintain the same level of performance even after being dipped in water, peeled off of the wafer and heated.
Though a study detailing the preliminary stages of the team’s results was published in December in the online version of Scientific Reports, Zheng said that work with the peel-and-stick cells has continued as researchers try to improve the technology.
“We proved the idea works, and that’s really exciting,” Zheng said. “We have two ultimate goals. One is to lower the cost of the solar cells by lowering the weight of substrate they are mounted on. The second is to make the substrate lighter and more flexible.”
Lee, a co-author of the study, agreed that the research team is now “mainly focused on how to put the cells on more flexible substrates.”
According to Lee, several companies—both within and outside the solar technology industry—have approached the team in the hope of collaboration.
“They want to apply our method to attach the solar cells on the surface of cars and boats—unusual applications of solar cells,” Lee said.
Zheng said that interested customers have also contacted the researchers about when the technology will reach the commercial market.
“The team receives a lot of inquiries on where this product is available,” Zheng said. “But we need more money to get it on the market sooner. Our next step is to scale this up, to apply the technology on a larger scale.”
While the researchers expressed satisfaction with their work so far, they plan to expand the project by recruiting more people for the research team and raising additional funds.
“This is really a demonstration—applications will be decided later,” Wang said. “Right now we have a good start.”