Researchers at Stanford University have developed a thin-film solar cell that can be applied to surfaces like a sticker or decal, opening up a wide variety of surfaces that could generate electricity.
Stanford University says, "Unlike standard thin-film solar cells, peel-and-stick thin-film solar cells do not require any direct fabrication on the final carrier substrate. This is a far more dramatic development than it may initially seem. All the challenges associated with putting solar cells on unconventional materials are avoided with the new process, vastly expanding the potential applications of solar technology."
Conventional solar cells are placed on rigid substrates like glass or silicon, which limits their potential use, and while thin-film solar cells offer flexibility, placing them on unconventional substrates has also brought a host of problems.
“Nonconventional or ‘universal’ substrates are difficult to use for photovoltaics because they typically have irregular surfaces and they don’t do well with the thermal and chemical processing necessary to produce today’s solar cells,” explains Xiaolin Zheng, a Stanford assistant professor of mechanical engineering and senior author of the paper. “We got around these problems by developing this peel-and-stick process, which gives thin-film solar cells flexibility and attachment potential we’ve never seen before, and also reduces their general cost and weight.”
The peel-and-stick cells have proven to be a major breakthrough. The researchers were able to peel them off and place them on window glass, paper, plastic and various other materials, all without losing any of the cell's original efficiency.
The cells are made of a unique silicon, silicon dioxide and metal “sandwich" that is topped off with a thermal release tape that allows it to be removed and then applied to a new surface. The cell can be removed from its silicon wafer after being submerged in room temperature water, which releases the adhesive. Heat is applied to the cell for 90 seconds and then its ready to be affixed to any surface using double-sided tape or adhesive.
The applications for these flexible, peel-and-stick solar cells could include bike helmets, cell phones, curved roofs, convex windows and clothing -- basically anything you can imagine.
Even cooler is that the peel-and-stick technology could be be used for things other than solar cells like thin-film electronics, including printed circuits, ultra thin transistors and LCDs.
“Obviously, a lot of new products – from ‘smart’ clothing to new aerospace systems – might be possible by combining both thin-film electronics and thin-film solar cells,” observes Zheng. “And for that matter, we may be just at the beginning of this technology. The peel-and-stick qualities we’re researching probably aren’t restricted to Ni/SiO2. It’s likely many other material interfaces demonstrate similar qualities, and they may have certain advantages for specific applications. We have a lot left to investigate.”