Whitney Palmer

RALEIGH — Researchers at N.C. State University have created mechanical leaves that mimic photosynthesis, nature’s perfect process of clean energy conversion.

By infusing a water-based gel with light-sensitive dyes, chemical and bioelectrical engineering professor Orlin Velev has developed bendable artificial “leaves” that function like solar cells.

The gel sits between graphite or carbon nanotube-coated anodes and cathodes – the points at which electric

Scientists at NCSU have created small artificial 'leaves' that convert sunlight into energy. Photo courtesy of North Carolina State University

currents flow into and out of electrical devices. When introduced to light, the light-sensitive particles become excited and produce electricity. 

“These ‘leaves’ naturally generate energy out of solar radiation,” Velev said. “And, because they don’t contain any silicon, they’re more environmentally friendly, and they’re easier to dispose of at the end of their life cycle.”

Velev refers to the method used to create the water-based gel as “kitchen science.” He dissolves the light-sensitive particles in agar, a gel that creates solid surfaces for scientific tests, and boils the mixture on the stove. The resulting gel is 98 percent water and is flexible.

The leaves can work with both synthetic light-sensitive molecules and natural ones, such as chlorophyll, the green pigment that allows plants to absorb and convert sunlight into energy. Currently, the leaves still produce a low amount of electricity, but with further study, Velev said, they could improve to become an affordable alternative to silicon-based solar cells.

For example, soft sheets of artificial leaves could one day cover house roofs as a method for generating electricity, he said.

But researchers must demonstrate that water-based solar cells can mass produce energy before the technology can be a feasible power source, said officials with the National Renewable Energy Laboratory at the U.S. Department of Energy.

“Identifying solar cell structures that are inexpensive and environmentally benign is important and useful,” said Sarah Kurtz, principal scientist at NREL. “This particular approach will need to demonstrate higher efficiencies before being useful.”

To read the Raleigh News & Observer article online: http://www.newsobserver.com/2010/11/29/831407/a-leaf-from-the-lab-makes-energy.html

To read the Charlotte Observer article online: http://www.charlotteobserver.com/2010/11/28/1872887/a-leaf-from-the-lab-makes-energy.html