2024-02-21 11:37:00
The ultra-thin modules are printed with semiconductor inks and can be adhered to the fabric
No more cold in winter and unbearable heat in summer. No more wondering how long your drone battery will last.
Scientists are creating ultra-thin flexible photovoltaic panels that can use light from the sun even where until recently it seemed impossible – to extend the range of drones or to heat and cool clothes depending on the weather and our needs. Science fiction? No! Clothing and applications based on ultra-light flexible “movable” solar panels may become a reality sooner than you think. Some of the recent developments in this direction are quite promising.
Engineers at the Massachusetts Institute of Technology (MIT) recently reported that they have developed ultra-thin flexible solar cells that can adhere to healthy tissues and thus turn them into a source of energy. According to the information of the scientists, the innovative solar cells developed by them are
thinner than a human hair, lighter than conventional solar panels and generate 18 times more power per kilogram
The creators explain that the secret is in the technology – the solar cells are created by printing from semiconductor inks.
Because they are thin and light, they can be laminated onto previously unused surfaces, the MIT engineers explain. For example – to be integrated into the sails of a boat to provide power while the sailboat is at sea, to be stuck on tents and tarps or placed on the wings of drones to extend and extend the range of flights.
“This lightweight solar technology can be easily integrated with minimal installation needs,” summarize the innovators.
Until now, measurements used to evaluate new solar cell technologies have typically been limited to its energy conversion efficiency and cost per watt. “However, just as important is the possibility of integration, that is, the ease with which the new technology can be adapted,” explains Vladimir Bulovich of the Research Laboratory of Electronics at MIT in Small Methods. Therefore, the team has been working in this direction for several years now.
It is known that
traditional silicon solar cells are fragile
To be well protected, they are covered with glass and housed in a heavy thick frame. This limits their deployment options, MIT says. So in 2016, the ONE Lab team produced ultrathin solar cells using a new class of thin-film materials. They are so light they can stand on a soap bubble, MIT innovators at Organic Electronics have demonstrated.
However, the technology requires complex processes that can be expensive and challenging for more mass production. Then they came up with an alternative – thin solar cells printed with a special ink that could be used for larger scale production.
Nanomaterials are used in the form of printed electronic inks. The experiments are carried out at MIT’s special laboratory for nanotechnology research MIT.nano.
The coating on the solar panel is only 3 microns thick
and is made with a special machine. Then, using a screen-printing-like technique that prints on silk surfaces, an electrode is deposited that completes the thin solar module. After peeling off the printed module from the plastic substrate, an ultralight solar device with a thickness of about 15 microns is obtained.
However, the innovators are aware that such thin solar modules can easily break if there is nothing to attach them to. To address this challenge, the MIT team decided that fabrics were a good solution for bonding the solar cells. This can provide stability and flexibility with little added weight.
So they discovered a fabric that weighs only 13 grams per square meter, known commercially as Dyneema. “This fabric is made of fibers that are so strong that they were used as ropes to raise the sunken cruise ship Costa Concordia from the bottom of the Mediterranean Sea,” MIT explains. The solar modules are adhered to this fabric with a thin layer of UV-curable adhesive only a few microns thick.
“It may seem simpler to print the solar cells directly onto the fabric, but this would limit the choice of possible fabrics to only those that are chemically and thermally compatible with the entire manufacturing step. Therefore, our approach is to separate the production of solar cells from their final integration into another material”, explains one of the researchers – Meioran Saravanapavanantham.
The tests showed that
the ultra-thin photovoltaic can generate 730 watts of power per kilogram when free-standing, and about 370 watts per kilogram if placed on solid tissue,
such as Dyneema. That’s about 18 times more power per kilogram than conventional solar cells.
“A typical Massachusetts rooftop solar installation is about 8,000 watts. To generate the same amount of energy, our fabric photovoltaics would only add about 20 kilograms to the roof of a house,” says Saravanapavanantham.
The researchers also tested durability and found that even after winding and unrolling the flexible solar panel more than 500 times, the cells retained more than 90% of their original power-generating capabilities.
However, the scientists found that in order to protect their creation from negative natural influences, such as moisture, for example, they had to wrap it in another material. Since currently known casings are too heavy, researchers are trying to develop ultra-thin packaging solutions that do not drastically increase the weight of the innovative material.
“We work for
to remove as much material as possible that is not solar active,
while maintaining the form and performance of ultralight and flexible solar structures.
We already know that the manufacturing process can be streamlined by printing loose substrates, similar to the process we use to fabricate the other layers. This would accelerate the path of this technology to the market,” says Jeremiah Muaura of the Electronics Research Laboratory at MIT.
This is not the only time scientists are trying to use solar energy outside the usual spheres – where lightness and flexibility are needed.
Engineers, chemists and materials specialists at Nankai University describe in detail in the journal Science a system of flexible solar-powered mini-panels that can be “embedded” in tissue. The secret is in several components integrated in microfiber, which provide all-day thermoregulation of the body temperature when the external temperatures change.
What the scientists are proposing is a two-way thermoregulation system that is powered by sunlight. The technology combines flexible solar mini-cells made of organic materials with a special device that can heat or cool. As a result, the energy received from the sun powers the device, which adapts to changes in ambient temperature. In other words, the energy obtained from the solar cells in the clothing warms when it’s cold, but can also cool when it’s hot outside.
The researchers build on a previous innovation to create microfiber-based metafabrics that can provide cooling during the day. What’s new is that they combine flexible solar cells with electrocaloric technology to create a microfiber-based fabric that can be used en masse.
At the heart of the new fabric is an organic photovoltaic module combined with a bidirectional electrocaloric device. Because both are flexible, the resulting device could be integrated into fabric used to make clothing. The bidirectionality of the device ensures that the clothes can provide warmth or coolness depending on the weather.
Test garments made with the new technology are promising, the researchers say. They report that the innovative fabrics respond quickly to changes in ambient temperature. Measurements have shown that clothes made from them are able to provide the person wearing them with about 10 calories of cooling and over 3 calories of heating. The clothes themselves are able to maintain the skin temperature in a thermal range of 32°C to 36°C, even when the outside temperature changes from 12.5°C to 37.6°C.
The innovative development attracts with its “self-sufficiency”. It draws energy only from the light of the sun, without the need for external sources. This will overcome the shortcomings of thermoregulatory garments that use passive and active systems. Passive systems rely on materials that offer unidirectional temperature regulation. Active systems try to add heating or cooling elements, but most such products need a lot of power or are otherwise bulky, making them impractical for everyday use.