Paper Thin Solar Cells Turn Any Surface Into A Power Source

Researchers have developed thin solar cells, measuring microns, that generate 730 watts of power per kilogram.

Photovoltaic cells are designed to power most of our everyday devices, and they also respond to our needs. But this does not prevent us from creating a more sustainable technology and developing the concept of photovoltaics.

MIT researchers have designed an ultralight fabric solar cell that can quickly and easily turn any surface into a power source. These strong, flexible solar cells are thinner than a human hair. They can provide energy while walking as a wearable power cloth or be portable and rapidly deployed to remote locations for assistance in emergencies. It is one hundredth the weight of conventional solar panels, generating 18 times more energy per kilogram. Because these solar cells are thin and light they can be laminated to many different surfaces.

The researchers used nanomaterials in the form of printable electronic inks to make these solar cells. It is then coated using a slot-die coater, which deposits layers of electronic materials onto a ready, releasable substrate just 3 microns thick. Using screen printing, an electrode is placed on the structure to complete the solar module. The researchers can peel the printed module, which is about 15 microns thick, from the plastic substrate, which will become an ultralight solar device.

The problem with deploying these solar cells is that they are thin and tear easily. To solve this problem the MIT team searched for a light, flexible, and high strength substrate that they could adhere the solar cells to. They identified fabrics as the best solution, because they provide mechanical strength and flexibility with little extra weight. They found a good material—a composite fabric weighing 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 the sheets of this fabric. This forms an ultra-light and mechanically strong solar structure.

When the device was tested, the researchers found that the device generated 730 watts of power per kilogram when freestanding and about 370 watts-per-kilogram when deployed on high-strength Dyneema fabric, which is about 18 times the power- per kilogram than conventional solar cells. The research plan to remove as much non-solar active area as possible will reduce the form factor and improve the performance of these ultralight and flexible solar structures.

References: Mayuran Saravanapavanantham et al, Printed Organic Photovoltaic Modules on Flexible Ultra-thin Substrates as Additive Power Sources, Small Methods (2022). DOI: 10.1002/smtd.202200940