Saturday, January 8, 2011

New Solar Cells Repair Themselves Like Plants

Purdue University researchers have designed solar cells that can repair themselves just like plants do.

"We've created artificial photosystems using optical nanomaterials to harvest solar energy that is converted to electrical power," said Jong Hyun Choi.

The design exploits the unusual electrical properties of structures called single-wall carbon nanotubes, using them as "molecular wires in light harvesting cells," Choi added.

Conventional photoelectrochemical cells contain light-absorbing dyes called chromophores, which degrade due to exposure to sunlight.

But the new solar cells overcome this problem just as nature does: by continuously replacing the photo-damaged dyes with new ones.

"This sort of self-regeneration is done in plants every hour," Choi said.

The carbon nanotubes work as a platform to anchor strands of DNA.

"The DNA recognizes the dye molecules, and then the system spontaneously self-assembles," Choi said.

However, using natural chromophores is difficult, and they must be harvested and isolated from bacteria, a process that would be expensive to reproduce on an industrial scale, Choi said.

"So instead of using biological chromophores, we want to use synthetic ones made of dyes called porphyrins," he said.

The findings were detailed in a November presentation during the International Mechanical Engineering Congress and Exhibition in Vancouver.


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