New solar cell would self-repair like natural plant systems
January 5, 2011
Researchers are creating a new type of solar cell designed to self-repair like natural photosynthetic systems in plants by using carbon nanotubes and DNA, an approach aimed at increasing service life 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 Univ.
The design exploits the unusual electrical properties of structures called single-wall carbon nanotubes, using them as "molecular wires in light harvesting cells," said Choi, whose research group is based at the Birck Nanotechnology and Bindley Bioscience centers at Purdue's Discovery Park.
"I think our approach offers promise for industrialization, but we're still in the basic research stage," he said.
Photoelectrochemical cells convert sunlight into electricity and use an electrolyte to transport electrons and create the current. The cells contain light-absorbing dyes called chromophores, chlorophyll-like molecules that degrade due to exposure to sunlight.
"The critical disadvantage of conventional photoelectrochemical cells is this degradation," Choi said.
The new technology overcomes 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 new concept could make possible an innovative type of photoelectrochemical cell that continues operating at full capacity indefinitely, as long as new chromophores are added.
The carbon nanotubes work as a platform to anchor strands of DNA. The DNA is engineered to have specific sequences of building blocks called nucleotides, enabling them to recognize and attach to the 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 might be removed by using chemical processes or by adding new DNA strands with different nucleotide sequences, kicking off the damaged dye molecules. New chromophores would then be added.
Two elements are critical for the technology to mimic nature's self-repair mechanism: molecular recognition and thermodynamic metastability, or the ability of the system to continuously be dissolved and reassembled.
The research is an extension of work that Choi collaborated on with researchers at the Massachusetts Institute of Technology and the Univ. of Illinois. The earlier work used biological chromophores taken from bacteria.
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.
September 5, 2014
Purdue University marked the opening of new Discovery Park interdisciplinary research facilities in drug development and cancer, key components of the Purdue Moves initiative, during a dedication ceremony on Friday (Sept. 5).Read Full Story
September 3, 2014
Purdue University is planning a ceremony to mark the opening of a nearly $29 million facility that will consolidate drug research centers at the school and a $16 million expansion of a cancer research center.Read Full Story
July 9, 2014
Moments after Dr. Jeff Crecelius completes a surgery, hopeful family members typically want to know if he was able to "get it all," or remove all of the cancerous tumor from the brain of a loved one. It's their emotional plea for reassurance. They want to know that the ordeal is completed and that the brain tumor has met its match — the hands of a skilled surgeon.Read Full Story