MIT researchers have developed a scalable fabrication technique to produce ultrathin, lightweight solar cells that can be stuck onto any surface. Credit: Melanie Gonick, MIT
Key Points:
- Researchers have developed a scalable fabrication technique to produce ultra-thin, lightweight solar cells that can be seamlessly added to any surface.
- The work relies on a composite fabric that weighs only 13 grams per square meter, commercially known as Dyneema.
- In tests, the resulting device generated 18 times more power-per-kilogram than conventional solar cells.
MIT engineers have developed ultralight fabric solar cells that can quickly and easily turn any surface into a power source.
Six years ago, the ONE Lab team produced solar cells using an emerging class of thin-film materials that were so lightweight they could sit on top of a soap bubble. But these ultrathin solar cells were fabricated using complex, vacuum-based processes, which can be expensive and challenging to scale up. In this work, they set out to develop thin-film solar cells that are entirely printable, using ink-based materials and scalable fabrication techniques.
To produce the solar cells, they use nanomaterials that are in the form of a printable electronic inks. Working in the MIT.nano clean room, they coat the solar cell structure using a slot-die coater, which deposits layers of the electronic materials onto a prepared, releasable substrate that is only 3 microns thick. Using screen printing, an electrode is deposited on the structure to complete the solar module. The researchers can then peel the printed module, which is about 15 microns in thickness, off the plastic substrate, forming an ultralight solar device.
But such thin, freestanding solar modules are challenging to handle and can easily tear, which would make them difficult to deploy. So, the MIT team searched for a lightweight, flexible, and high-strength substrate they could adhere the solar cells to.
They found an ideal material—a composite fabric that weighs only 13 grams per square meter, commercially known as Dyneema. By adding a layer of UV-curable glue, which is only a few microns thick, they adhere the solar modules to sheets of this fabric. This forms an ultra-light and mechanically robust solar structure.
When they tested the device, the MIT researchers found it could generate 730 watts of power per kilogram when freestanding and about 370 watts-per-kilogram if deployed on the high-strength Dyneema fabric, which is about 18 times more power-per-kilogram than conventional solar cells.
“A typical rooftop solar installation in Massachusetts is about 8,000 watts. To generate that same amount of power, our fabric photovoltaics would only add about 20 kilograms (44 pounds) to the roof of a house,” said Jeremiah Mwaura, a research scientist in the MIT Research Laboratory of Electronics.
They also tested the durability of their devices and found that, even after rolling and unrolling a fabric solar panel more than 500 times, the cells still retained more than 90 percent of their initial power generation capabilities.
While the solar cells are far lighter and much more flexible than traditional cells, they would need to be encased in another material to protect them from the environment.
“Encasing these solar cells in heavy glass, as is standard with the traditional silicon solar cells, would minimize the value of the present advancement, so the team is currently developing ultrathin packaging solutions that would only fractionally increase the weight of the present ultralight devices,” said Mwaura.
Information provided by MIT.