Ever felt thwarted with your typical solar cells with only limited power supply and limited applications? Researchers at Stanford University have been working on to shake off such frustration and finally come up with a solution.

Scientists at Stanford University in collaboration with the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) have developed Peel-and-Stick versions of solar cells that can charge your cell phones, change the tint on windows and any other battery-powered products.

“These cells have been used before for nanowire based electronics, but the Stanford-NREL partnership has conducted the first successful demonstration using actual thin film solar cells,” said Qi Wang, principal scientist at NREL.

As the name says “Peel-and-Stick”, these cells can be attached to almost any surface from papers to window panes and then peeled off like band-aids. But, to acquire these properties, a silicon substrate is used from which one-micron thick thin-film solar cells are removed and later fabricated by dipping them in water at room temperature and heat at about 90 degree celsius.

“NREL’s cells could be made easily on Stanford’s peel off substrate. NREL’s amorphous silicon cells were fabricated on nickel-coated Si/SiO2 wafers. A thermal release tape attached to the top of the solar cell serves as a temporary transfer holder. An optional transparent protection layer is spin-casted in between the thermal tape and the solar cell to prevent contamination when the device is dipped in water. The result is a thin strip much like a bumper sticker: the user can peel off the handler and apply the solar cell directly to a surface. The cells’ ability to adhere to a universal substrate is unusual; most thin-film cells must be affixed to a special substrate. The peel-and-stick approach allows the use of flexible polymer substrates and high processing temperatures. The resulting flexible, lightweight, and transparent devices then can be integrated onto curved surfaces such as military helmets and portable electronics, transistors and sensors.” NREL said in a post on their official site.

Figure 1: Procedures of the peel-and-stick process.

(a) As-fabricated TFSCs on the original Si/SiO2 wafer. (b) The TFSCs are peeled off from the Si/SiO2 wafer in a water bath at room temperature. (c) The peeled off TFSCs are attached to a target substrate with adhesive agents. (d) The temporary transfer holder is removed, and only the TFSCs are left on the target substrate.
(a) As-fabricated TFSCs on the original Si/SiO2 wafer. (b) The TFSCs are peeled off from the Si/SiO2 wafer in a water bath at room temperature. (c) The peeled off TFSCs are attached to a target substrate with adhesive agents. (d) The temporary transfer holder is removed, and only the TFSCs are left on the target substrate. | Credit: Stanford University

Figure 2: TFSCs at different stages of the peel-and-stick process.

(a) As-fabricated TFSCs on the original Ni coated Si/SiO2 wafer (left). The donor Si/SiO2 wafer is clean and reusable after the peeling-off step (middle). The TFSCs are held by a temporary transfer holder (right). (b) TFSCs on cell phone (left), business card (middle), and building window (right).
(a) As-fabricated TFSCs on the original Ni coated Si/SiO2 wafer (left). The donor Si/SiO2 wafer is clean and reusable after the peeling-off step (middle). The TFSCs are held by a temporary transfer holder (right). (b) TFSCs on cell phone (left), business card (middle), and building window (right). | Credit: Stanford University

Figure 3: Comparisons of the TFSC performances before and after the peel-and-stick process.

The representative I–V characteristics (below average performance) of the as-fabricated TFSCs (green lines with stars) are the same as those after transferring the TFSCs (red lines with dots) to stainless steel (left) and soda-lime glass (right).
The representative I–V characteristics (below average performance) of the as-fabricated TFSCs (green lines with stars) are the same as those after transferring the TFSCs (red lines with dots) to stainless steel (left) and soda-lime glass (right). | Credit: Stanford University

Figure 4: Mechanical flexibility of the transferred TFSCs.

(a) The I–V characteristics of the TFSCs remain the same after bending the flexible sheet with a range of bending radius from ∞ down to 7 mm. (b) The flexible TFSCs show no performance change over 3000 cycles of bending with bending radius about 10 mm. Note that all the I–V characteristics are measured when the TFSCs are flat to prevent any damage from the sharp tungsten probe tips during the measurements.
(a) The I–V characteristics of the TFSCs remain the same after bending the flexible sheet with a range of bending radius from ∞ down to 7 mm. (b) The flexible TFSCs show no performance change over 3000 cycles of bending with bending radius about 10 mm. Note that all the I–V characteristics are measured when the TFSCs are flat to prevent any damage from the sharp tungsten probe tips during the measurements. | Credit: Stanford University

See the complete report about Peel-and-Stick Solar Panels at Scientific Reports and NREL.