Researchers at New Jersey Institute of Technology (NJIT) have developed an inexpensive solar cell that can be painted or printed on flexible plastic sheets.

“Someday, homeowners will even be able to print sheets of these solar cells with inexpensive home-based inkjet printers. Consumers can then slap the finished product on a wall, roof or billboard to create their own power stations,” said Somenath Mitra, Ph.D., lead researcher, professor and acting chair of NJIT’s Department of Chemistry and Environmental Sciences.

Harvesting energy directly from abundant solar radiation using solar cells is increasingly emerging as a major component of future global energy strategy, Mitra said. Yet, when it comes to harnessing renewable energy, challenges remain.

Expensive, large-scale infrastructures, such as windmills or dams, are necessary to drive renewable energy sources, such as wind or hydroelectric power plants. Purified silicon, also used for making computer chips, which continue to rise in demand, is a core material for fabricating conventional solar cells. However, the processing of a material such as purified silicon is beyond the reach of most consumers.

“Developing organic solar cells from polymers, however, is a cheap and potentially simpler alternative,” Mitra said. “We foresee a great deal of interest in our work because solar cells can be inexpensively printed or simply painted on exterior building walls and/or rooftops. Imagine some day driving in your hybrid car with a solar panel painted on the roof, which is producing electricity to drive the engine. The opportunities are endless.”

The solar cell developed at NJIT uses a carbon nanotubes complex, which is a molecular configuration of carbon in a cylindrical shape. Although estimated to be 50,000 times smaller than a human hair, just one nanotube can conduct current better than any conventional electrical wire.

Mitra and his research team took the carbon nanotubes and combined them with tiny carbon fullerenes (sometimes known as buckyballs) to form snake-like structures. Buckyballs trap electrons, although they can’t make electrons flow. Add sunlight to excite the polymers, and the buckyballs will grab the electrons. Nanotubes, behaving like copper wires, then will be able to make the electrons or current flow.

“Someday, I hope to see this process become an inexpensive energy alternative for households around the world,” Mitra said.  EC