It's a Small World After All

TAMPA, Fla. (Nov. 18, 2008) - The big question about how to power tiny microelectronic machines (MEMS) has found a small but significant answer through the research of University of South Florida physics professors Xiaomei Jiang and Jian Zhang and USF graduate student Jason Lewis.

The research team, specialists in organic electronic materials, solar cells and carbon nanotubes, has 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 exploit solar energy and convert it to electrical power.

Publishing their work in the inaugural issue of the Journal of Renewable and Sustainable Energy, published by the American Institute of Physics, the research team explained that 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.

“These materials have a lot more potential than traditional silicon,” explained Jiang. “They could be sprayed on any surface that is exposed to sunlight, such as a uniform, a car or a house.”

The cells they developed as a power source for running MEMS were fashioned into an array of 20 tiny solar cells 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 gotten their solar cells delivering up to a 7.8 volt zap. It’s just a matter of time, they say, before the voltage is optimized.

“The combination of miniaturization and using flexible polymers in these solar cells represents a significant scientific and technological step forward in converting solar energy for a host of applications,” Pritish Mukherjee, chair of the USF Department of Physics. “Their work is timely because of the critical need to develop sustainable alternative energy sources and we look forward to their other significant developments in the future.”

Jiang and colleagues were funded in part with the support of the Integrated Functional Materials initiative funded at USF Physics through a $1.6 million grant from the U.S. Army Medical Research and Materiel Command.

The University of South Florida is one of the nation's top 63 public research universities and one of 39 community-engaged, four-year public universities as designated by the Carnegie Foundation for the Advancement of Teaching. USF was awarded more than $360 million in research contracts and grants in FY 2007/2008. The university offers 219 degree programs at the undergraduate, graduate, specialist and doctoral levels, including the doctor of medicine. The university has a $1.8 billion annual budget, an annual economic impact of $3.2 billion, and serves more than 46,000 students on campuses in Tampa, St. Petersburg, Sarasota-Manatee and Lakeland. USF is a member of the Big East Athletic Conference.

– USF–

News release by Randolph Fillmore