Engineers at the Massachusetts Institute of Technology (MIT) claimed to have developed an ultralight fabric solar cell that can turn any surface into a power source.

This research was funded, in part, by the MIT Energy Initiative, the U.S. National Science Foundation, and the Natural Sciences and Engineering Research Council of Canada.

These solar cells are considered durable, flexible, and even thinner than human hair, which can be glued to a strong, lightweight fabric, making them easy to install on a fixed surface.

On testing the device, the MIT team found it could generate 730W of power per kilogram when freestanding and about 370W per kilogram if deployed on the high-strength Dyneema fabric, which is about 18 times more power-per-kilogram than conventional solar cells.

On testing the device’s durability, it was found that even after rolling and unrolling a fabric solar panel more than 500 times, the cells retained more than 90% of their initial power generation capabilities.

The researchers claimed that lightweight solar technology could be easily integrated into built environments with minimal installation needs.

Made from semiconducting inks, these cells are one hundredth the weight of conventional solar modules and generate 18 times more power per kilogram, the researchers said.

The semiconducting ink printing process can be scaled in the future for large-area manufacturing.

Vladimir Bulović, leader of the Organic and Nanostructured Electronics Laboratory (ONE Lab) and director of MIT.nano, said that the metrics to evaluate a new solar cell technology are typically the power conversion efficiency, cost in dollars-per-watt and the technology’s integrability, meaning the ease with which the new technology can be adapted.

Bulovic added that the lightweight nature of the solar fabrics makes them adaptable.

Thin-Film Solar Cells

The researchers set out to develop thin-film solar cells that are entirely printable, using ink-based materials and scalable fabrication techniques.

The cells were produced using nanomaterials in the form of printable electronic ink, wherein they coat the solar cell structure using a slot-die coater, which deposits layers of the electronic materials onto a prepared, releasable substrate measuring three microns thick.

An electrode is deposited on the structure using screen printing to complete the solar module. The 15 microns thick printed module is then peeled off the plastic substrate, forming an ultralight solar device.

The MIT team identified fabrics as the optimal solution to find a high-strength substrate that could adhere to the solar cells, as they provide mechanical resilience and flexibility with little added weight.

They found an ideal material — a strong composite fabric that weighed only 13 grams per square meter, commercially known as Dyneema.

The researchers added a layer of UV-curable glue (only a few microns thick), and they adhered the solar modules to sheets of this fabric. This forms an ultra-light and mechanically robust solar structure.

While these cells are far lighter and much more flexible than traditional cells, they also 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,” the researchers said.

Currently, the team is working to remove as much of the non-solar-active material as possible while retaining the form factor and performance of these ultralight and flexible solar structures, to accelerate the translation of this technology into the market.

Early this year, researchers from MIT developed a method that uses static electricity to keep solar panels free of dust, removing the need for cleaning with water.

Previously, researchers from the National Renewable Energy Laboratory and the University of Wisconsin, Stout, claimed that glass-walled buildings could be made 40% more energy efficient by adding thermally efficient photovoltaic windows.

Image Source: MIT