New material for 'bendable' solar cells

Sept. 27, 2011 - upi.com

EVANSTON, Ill., Sept. 27 (UPI) -- A new material for solar cells -- a transparent conductor made of carbon nanotubes -- could revolutionize the way solar power is harvested, U.S. scientists say.

The material could be an affordable and flexible alternative to current technology, which is mechanically brittle and reliant on a relatively rare mineral, a release by Northwestern University said Tuesday.

Northwestern researchers said the material's mechanical flexibility could allow solar cells to be integrated into fabrics and clothing, creating portable energy for everything from personal electronics to military operations.

Solar cells require a transparent conductor layer that allows light to pass into the cell and electricity to pass out, so the conductor must be both electrically conductive and optically transparent. Indium tin oxide, the material predominantly in use currently, is mechanically brittle and relies on the relatively rare and expensive element indium.

The Northwestern team has created an alternative to indium tin oxide using single-walled carbon nanotubes, tiny, hollow cylinders of carbon just one nanometer in diameter.

Because carbon nanotubes are flexible they could lead to new applications in solar cells such as military tents incorporating the flexible solar cells into tent material to provide power directly for soldiers in the field, or the cells could be integrated into clothing, backpacks or purses for wearable electronics.

"With this mechanically flexible technology, it's much easier to imagine integrating solar technology into everyday life, rather than carrying around a large, inflexible solar cell," materials scientist Mark C. Hersam said.