Video: MIT engineers develop paper-thin solar cells that can power any surface

The ultralight solar cells are made of semiconducting inks using printing processes that can be scaled in the future to large-area manufacturing.

A group of engineers at MIT have developed a rather interesting solution to be deployed in remote locations or for assistance in emergencies: solar cells made of ultralight fabric that can turn any surface into a power source.

Thinner than human hair, the durable, flexible solar cells are stuck on a strong, lightweight fabric that makes them very easy to affix to a surface, just like a sticker.

The research is published in Small Methods.

The solar cells can be laminated onto many surfaces.

"The metrics used to evaluate a new solar cell technology are typically limited to their power conversion efficiency and their cost in dollars-per-watt. Just as important is integrability — the ease with which the new technology can be adapted," Vladimir Bulović, the Fariborz Maseeh Chair in Emerging Technology, leader of the Organic and Nanostructured Electronics Laboratory (ONE Lab), director of MIT.nano, and senior author, said in a statement.

"The lightweight solar fabrics enable integrability, providing impetus for the current work. We strive to accelerate solar adoption, given the present urgent need to deploy new carbon-free sources of energy," he continued.

Applications are aplenty; these ultralight solar cells can be easily integrated onto the sails of a boat to provide power while at sea, adhered onto tents and tarps that are deployed in disaster recovery operations, or applied onto the wings of drones to extend their flying range, as per the release.

The ultralight solar cells is one hundredth the weight of regular ones.

The thin-film solar cells weigh about 100 times less than conventional solar cells.

The paper-thin solar cells are made of semiconducting inks using printing processes that can be scaled in the future to large-area manufacturing. One-hundredth the weight of conventional solar cells, the former generates 18 times more power per kilogram, which is quite impressive.

The solar cells were glued on a composite fabric that weighs only 13 grams per square meter, known as Dyneema. This fabric is known to be sturdy; adhering the solar modules to sheets of this fabric only resulted in a mechanically robust solar structure.

"While it might appear simpler to just print the solar cells directly on the fabric, this would limit the selection of possible fabrics or other receiving surfaces to the ones that are chemically and thermally compatible with all the processing steps needed to make the devices. Our approach decouples the solar cell manufacturing from its final integration,” Mayuran Saravanapavanantham, electrical engineering and computer science graduate student at MIT, explained.

The device can generate 730 watts of power per kilogram.

The MIT researchers found that the device 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," he said.

These solar cells, however, need to be encased in a material that can 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 Jeremiah Mwaura, a research scientist in the MIT Research Laboratory of Electronics.

Study Abstract:

Thin-film photovoltaics with functional components on the order of a few microns, present an avenue toward realizing additive power onto any surface of interest without excessive addition in weight and topography. To date, demonstrations of such ultra-thin photovoltaics have been limited to small-scale devices, often prepared on glass carrier substrates with only a few layers solution-processed. We demonstrate large-area, ultra-thin organic photovoltaic (PV) modules produced with scalable solution-based printing processes for all layers. We further demonstrate their transfer onto lightweight and high-strength composite fabrics, resulting in durable fabric-PV systems ∼50 microns thin, weighing under 1 gram over the module area (corresponding to an area density of 105 g m−2), and having a specific power of 370 W kg−1. Integration of the ultra-thin modules onto composite fabrics lends mechanical resilience to allow these fabric-PV systems to maintain their performance even after 500 roll-up cycles. This approach to decoupling the manufacturing and integration of photovoltaics enables new opportunities in ubiquitous energy generation.

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