Tiny solar cells that power tiny microelectromechanical systems (MEMS) could be sprayed onto a soldiers backpack, uniform or military vehicle possibly eliminating the use of heavy portable batteries carried by soldiers for their electrical requirements.
The US Army are looking into a wide variety of low-power sensors that when integrated with other technologies, could provide real-time data that monitors and records the soldier's body and environment. The devices required to do this, need batteries which are carried on a soldier's back and can weigh between 30 - 40 pounds - contributing to around half the weight they carry on their back. These batteries are estimated to cost around $57,000 a year per soldier.
A project part funded by U.S. Army Medical Research and Materiel Command is being carried out by researchers at the University of South Florida who have developed solar cells that are so small - a quarter of the size of a 12-point font letter 'o' - that they can be sprayed or painted on a flexible backing where they can capture sunlight and convert it to electrical power.
The team explained in an earlier press release that, unlike conventional silicon solar cells, the tiny cells they devised are made of an organic polymer (long organic molecules strung together in repeating units). The polymer has the same electrical properties as silicon, the material of which computer chips are fabricated, and could be sprayed on any surface that is exposed to sunlight, such as a uniform, a car or a house.
The cells developed as a power source to run MEMS were fashioned into an array of 20 tiny solar cells (see top image) that can be used in devices such as microsensors made of carbon nanotubes and used to detect dangerous toxins or chemical leaks. Such devices need a 15-volt power source to work and the USF researchers have managed to get their solar cells delivering up to 7.8 volts. It is just a matter of time, they say, before the voltage is optimized.
"The world's next generation of microelectronics may be dominated by 'plastic electronics' and organic solar cells are expected to play an important role in these future technologies," writes physics professors Xiaomei Jiang of USF.
Their work has been published in the Journal of Renewable and Sustainable Energy, published by the American Institute of Physics.
Top image: USF