New Solar Panels Made Thinner Than Human Hair, 18 Times More Power Capacity

In comparison to today's glass and silicon-based solar panels, MIT researchers have created solar panels that are 18 times more poer capacity per kilogram and are thinner than a human hair. In actuality, the weight of these solar cells is one hundredth that of traditional photovoltaics.

Ready to Roll

The implications could be significant if this technology could ever be scaled up. The American countryside is covered in tens of thousands of warehouses.

Vladimir Bulović, an MIT professor of electrical engineering and computer science, said that although expansive roofs would be ideal locations for solar power installations, they couldn't support the weight of today's silicon solar panels. Lighter solar panels would make it possible to electrify those roofs much more quickly than is currently possible.

Bulović imagines a day when solar carpets the size of a roof could be purchased and easily unrolled.

Solar Panels Thinner than Human Hair

Additionally, tents, drone wings, and boat sails could all be laminated with incredibly thin solar cells. They could be particularly useful for providing electricity in off-the-grid areas and for relief operations in the event of a disaster.

According to Bulović, silicon solar panels' weight has prevented solar power from being deployed more quickly than it has thus far. Thin-film solar cells, like those produced by First Solar, are lighter, as well as simpler, and less expensive to manufacture. However, they are still placed on a piece of glass, making the finished modules just as heavy as regular ones.

The scientist claims that solar panel manufacturers would be able to produce much larger solar panels, and installation would be significantly less expensive. According to World-Energy, the few attempts to create ultra-thin solar cells embedded in flexible plastic films have so far resulted in very small experimental devices, fragile products, or products that don't perform well enough for everyday use.

Parylene, Printable Inks, Silver Nanowires

A layer of parylene that was a few micrometers thick was applied by the MIT team to a sheet of plastic. Electrical insulation and resistance to chemical and moisture corrosion are all properties of parylene. On top of that, the researchers used printable inks using a variety of materials to deposit various solar-cell layers. It takes up to three micrometers to cover the entire solar-cell structure. The active light-to-electricity conversion layer was made up of an organic semiconductor, and the transparent electrodes were made up of silver nanowires and a conductive polymer. According to Bulović, perovskites could also be used for light conversion, but while those materials would have a higher efficiency, they degrade in oxygen and moisture.

The team then applied a thin layer of glue to the finished solar cells' edges and managed to bring them into contact with a durable, thin, readily available performance fabric. Then, as they pulled off the fabric, the solar stack on top and the incredibly thin parylene substrate peeled off with it, transferring the solar modules onto the fabric.

18 Times Power per Kilogram, Scalable Tech

The fabric modules weighed 0.1 kilograms per square meter and had an energy capacity of 370 watts per kilogram. Comparatively, thin-film solar modules made of cadmium-telluride placed on glass substrates have a power density of 13 W/kg and weigh 14 kg/m2, while commercial residential silicon solar panels have a power density of 20 W/kg and weigh as much as 10.7 kg/m2.

Although the roughly 10 x 10-centimeter laboratory-scale devices Bulović's team has created, he claims that everything they have shown can be scaled up without any obstacles.

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More Testing, Better Packaging

For use in the real world, the paper-thin solar cells will have to be stable. The scientists intend to conduct more thorough testing and create a thin, weather-resistant encapsulation layer to protect the solar cells for many years.

Bulović claims that, without packaging, the cells as-is could last one or two years. However, packaging could extend its life to five to ten years, which is more than enough.

According to IEEE Spectrum, Bulović has already founded three businesses, including the transparent solar cell manufacturer Ubiquitous Energy and the quantum-dot electronics company QD Vision, which Samsung purchased. Through a recently established startup called Active Surfaces, he now intends to further develop and commercialize the novel ultrathin solar cells.

The research presented by Bulović and his colleagues on their new device was recently published in the journal Small Methods.

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