New self-repairing solar cells could cut maintenance costs and increase overall service life

Researchers from Purdue University have developed self-repairing solar cells that could reduce maintenance costs and increase their overall service life. 

Jong Hyun Choi, study leader and an assistant professor of mechanical engineering at Purdue University, along with Purdue University students Benjamin A. Baker, Tae-Gon Cha, M. Dane Sauffer and Yujun Wu, have been working on new, self-repairing solar cells that are capable of mimicking plant-like natural photosynthetic processes. 

In conventional photoelectrochemical cells, sunlight is converted into electricity and an electrolyte is used to move electrons which creates a current. The problem is that these cells have chromophores, which are light-absorbing dyes that degrade after being exposed to sunlight.

But with self-repairing solar cells, this would no longer be an issue. To create these new solar cells, the Purdue research team utilized two crucial elements needed to make this technology imitate nature, which was molecular recognition and thermodynamic metastability. This allows the system to be dissolved and reassembled on a regular basis, replacing photo-damaged dyes continuously.

Carbon nanotubes and DNA were used to make such a system possible. The self-repairing solar cell design utilizes the single-wall carbon nanotubes' unusual electrical characteristics as "molecular wires in light harvesting cells." The carbon nanotubes then anchor strands of DNA, which are engineered to nucleotides  with specific sequences. This allows the strands to recognize and bind to the chromophores. When this occurs, the system will automatically self-assemble. 

As long as new chromophores are added, this new system could work continuously at full capacity. In nature, plants perform self-regeneration every hour, and this system closely resembles that process. The difference is that natural chromophores are difficult to obtain since they need to be isolated from bacteria, so instead, researchers are using synthetic chromophores made of porphyrins.

"We've created artificial photosystems using optical nanomaterials to harvest solar energy that is converted to electrical power," said Choi. "I think our approach offers promise for industrialization, but we're still in the basic research stage."

 dailytech.com