Ultra-light solar cells can turn surfaces into power sources

The new battery developed by the MIT research team is as thin as paper and can turn any surface into a power source. Image source: Physicists Organization Network

Engineers from the Massachusetts Institute of Technology (MIT) published a paper in the latest issue of the journal Small Methods, saying that they have developed an ultra-light solar cell that can quickly and easily turn any surface into a power source. This solar cell, which is thinner than a human hair and is attached to a piece of fabric, weighs only one hundredth of a traditional solar panel, but generates 18 times more electricity per kilogram. It can be integrated into sails, disaster relief tents and tarpaulins, drone wings, and various building surfaces.

To produce solar cells, the MIT Organic and Nanostructured Electronics Laboratory team used nanomaterials in the form of electronic ink. In a nano clean room, they used an extrusion coater to deposit a layer of nanoelectronic materials onto a 3-micron-thick substrate, then used screen printing to print electrodes and complete the solar module, and then peeled the printed module, which was about 15 microns thick, from the plastic substrate to form an ultra-light solar device module.

But this thin and independent solar module is difficult to handle and easily torn, making it difficult to deploy. To this end, the research team needed to find a lightweight, flexible substrate to which the solar cells were attached, and they eventually found a composite material called Dyneema, which weighs only 13 grams per square meter. By adding a layer of curing glue only a few microns thick, they attached the solar modules to Dyneema, ultimately forming an ultra-light and strong solar structure.

Test results show that stand-alone solar cells can generate 730 watts of power per kilogram. If they are attached to high-strength "Dyneema" fabric, they can generate about 370 watts of power per kilogram, which is 18 times that of traditional solar cells. Moreover, even after the fabric solar cells are rolled up and unfolded more than 500 times, they still maintain more than 90% of their initial power generation capacity. This battery production method can be expanded to produce flexible batteries with larger areas.

However, the researchers stressed that although their solar cells are lighter and more flexible than traditional batteries, the carbon-based organic materials used to make the batteries will interact with moisture and oxygen in the air, which may reduce the performance of the batteries. Therefore, another material is needed to protect the batteries from environmental influences. They are currently developing ultra-thin packaging solutions.