For all their promise, solar cells have frustrated scientists in one crucial regard – most are rigid. They must be deployed in stiff and often heavy fixed panels, limiting their applications. So researchers have been trying to get photovoltaics to loosen up. The ideal: flexible, decal-like solar panels that can be peeled off like band-aids and stuck to virtually any surface, from papers to window panes.
Now the ideal is real. Stanford researchers have succeeded in developing the world’s first peel-and-stick thin-film solar cells.
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.
The new process involves a unique silicon, silicon dioxide and metal “sandwich.” First, a 300-nanometer film of nickel (Ni) is deposited on a silicon/silicon dioxide (Si/SiO2) wafer. Thin-film solar cells are then deposited on the nickel layer utilizing standard fabrication techniques, and covered with a layer of protective polymer. A thermal release tape is then attached to the top of the thin-film solar cells to augment their transfer off of the production wafer and onto a new substrate.
The solar cell is now ready to peel from the wafer. To remove it, the wafer is submerged in water at room temperature and the edge of the thermal release tape is peeled back slightly, allowing water to seep into and penetrate between the nickel and silicon dioxide interface.
The solar cell is thus freed from the hard substrate but still attached to the thermal release tape. Zheng and team heat the tape and solar cell to 90°C for several seconds, and the cell can then be applied to virtually any surface using double-sided tape or other adhesive. Finally, the thermal release tape is removed, leaving just the solar cell attached to the chosen substrate.
While others have been successful in fabricating thin-film solar cells on flexible substrates before, those efforts have required modifications of existing processes or materials, notes the researcher.
Moreover, peel-and-stick technology isn’t necessarily restricted to thin-film solar cells, the researcher said. The researchers believe the process can also be applied to thin-film electronics, including printed circuits, ultra thin transistors and LCDs.
This story is reprinted from material from Stanford University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.