Powering your dress

Ultra-thin solar cells flexible enough to bend around small objects, such as this 6-mm-diameter glass rod. Credit: Juho Kim, et al./APL

Researchers at the Gwangju Institute of Technology in South Korea have been able to create a solar cell panel that is so thin, 1µm, that it can easily be folded around a radium, of 1.4 mm. This makes it possible to bend it around objects like a wrist watch and even weaved into a dress fabric.

The thickness, or rather the thinness, of this solar cell is really what sets it apart from competition. A human hair is no thinner than 17µm, hence it is at least 17 times thicker and even the most thinner solar cells so far are at least 4 times thicker.

To reach such minimal thickness researchers have to invent a way to stick the silicon gallium arsenide on the surface without using glue whose thickness alone would have exceeded the 1µm. They heat up the substrata that serves as electrode at 170° and make the cell semiconductor stick through pressure. The electrode also acts as light reflector to increase the yield of the cell.

Notice that there are solar cells with the active layer just 1µm thick but these cells are obtained through etching, so although the active part is 1µm thick the whole cell is much thicker and this makes it unsuitable for several of the foreseen applications (like the weaving in a dress) and greatly diminishes the folding capabilities.

The researchers hint as possible use the integration of the solar cell in a glasses frame to power active devices embedded in the glasses, like hearing aids or a LCD screen, and the embedding in dress fabric to power wearables.

Author - Roberto Saracco

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