Scientists develop self-repairing solar cell -

Scientists have developed a new form of solar cell which is able to mimic the photosynthetic systems found naturally in plants in order to self-repair.

By using carbon nanotubes and DNA, researchers at Purdue University in Lafayette have developed an approach that is aimed at increasing the life span of solar panels and reducing cost.

"We've created artificial photosystems using optical nanomaterials to harvest solar energy that is converted to electrical power," said Jong Hyun Choi, an assistant professor of mechanical engineering at Purdue University.

Commonly used petroelectrochemical cells convert sunlight into electricity and use a liquid electrolyte, transporting electrons in order to create the current.  However as these contain dyes known as chromophores which are affected by sunlight and are subject to degredation after usage.

"The critical disadvantage of conventional photoelectrochemical cells is this degradation," Choi said.

However the new technology, which utilises the unusual electrical properties that are found in single-wall carbon nanotubes, is able to overcome this problem in precisely the way that mother nature does by constantly replacing the photo-damaged dyes with new ones. "This sort of self-regeneration is done in plants every hour," explained Choi.

It is thought that the new development could make it possible for a new type of photoelectrochemical that would be able to continue to repair itself forever, as long as new chromophores are added.

The carbon nanotube structures essentially function as anchors for strands of DNA acting as "molecular wires in light harvesting cells".  The strands are engineered so as to be able to recognize and attach themselves to chromophores.

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

When the chromophores are ready to be replaced they can be removed before being replaced by synthetic chromophores, as natural ones would prove tricky to isolate.

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

"I think our approach offers promise for industrialization, but we're still in the basic research stage," he said.