Spray-on solar cells a step closer
Researchers have developed some of the tiniest solar cells ever made and believe the organic material could potentially turn any surface into a power source.
In research published in the Journal of Renewable and Sustainable Energy, Assistant Professor Xiaomei Jiang of the University of South Florida and colleagues have managed to draw several volts of electricity from a small array of the cells, each a quarter of the size of a grain of white rice.
Solar cells, which convert energy from the sun into electricity, are in increasing demand amid unstable oil prices and concerns over global warming.
Most conventional solar cells are made up of silicon wafers, a brittle substance that limits where they can be placed.
Many teams of scientists are working on different ways to make solar cells more flexible in the hopes of taking better advantage of energy from the sun.
The tiny cells createrd by Jiang and colleagues are made from an organic polymer that has the same electrical properties of silicon wafers but can be dissolved and applied to flexible materials.
"The main components are carbon and hydrogen - materials that are present in nature and are environmentally friendly," says Jiang.
She believes the material could be sprayed on any surface that is exposed to sunlight.
"Because it is in a solution, you can design a special spray gun where you can control the size and thickness. You could produce a paste and brush it on," says Jiang.
Eventually, Jiang envisions the solar cells being used as a coating on a variety of surfaces, including clothing.
They might generate energy to power small electronic devices or charge a cell phone.
The solar array they developed, consisted of 18 cells and measuring 2.2 square centimetres, and was able to generate 7.8 volts of electricity, with a current as high as 55 microamps.
Her team is now refining the manufacturing process with the hope of doubling that output to 15 volts. "It's a matter of months," Jiang says.