In the future, power suits may do more than command attention and exude confidence. They may actually charge your electronic devices.
A team of scientists led by John Badding, a chemistry professor at Pennsylvania State University has made a solar cell into the shape of a fiber, which can be woven into
fabric. That fabric could be turned into a garment that harnesses energy from the sun and turns it into renewable electricity.
The researchers combined glass optical fibers with traditional photovoltaics normally used for rooftop solar panels. Both of these components are typically rigid and stiff. But Pier Sazio, a
research fellow in optoelectronics at the University of Southampton and
one of the co-authors, told Discovery News that silicon becomes flexible
when it's very thin, while also retaining its strength.
To make the fiber, they mixed silicon with other elements, including boron and helium and then turned it into a hot, high-pressure gas. Next, they filled a thin, hollow fiber optic with the gas mixture. As it cooled, the silicon mixture formed three concentric layers.
The innermost layer, called the "p" layer, was positively charged and accepted electrons. The outermost layer, called the "n" layer, was negatively charged and had an excess of electrons. A middle layer between the two, called the "i" layer, was neutral.
As sunlight hits the fiber, photons knock electrons from the outermost "n" layer and send them into the "p" layer. That generates current, just like an ordinary solar celm, except this one is cylindrical rather than flat.
By attaching two small electrodes, one to the "p" layer and the other on the "n" layer, one would be able to extract the charge for power.
Because the fiber is round, it's able to pick up sunlight from any angle. The thinness of the fiber — on the order of 15 micrometers, which is about the same as acrylic — allows it to be woven and twisted and turned into clothing that could power or charge a small electronic device. No surprisingly, the military has been interested: modern soldiers carry a lot of electronic gear and batteries are heavy.
The work appeared online on Dec. 4 and wil be in an upcoming print issue of Advanced Materials.
Credit: Badding, et. al, Pennsylvania State University