Photoelectrochemical cells that convert sunlight into electricity contain light-absorbing dyes called chromophores, similar to chlorophyll molecules in plants, that degrade due to exposure to sunlight. "The critical disadvantage of conventional photoelectrochemical cells is this degradation," Choi said.
The new technology gets around this problem in the same way 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.
Strands of DNA anchored to a platform of carbon nanotubes are engineered to recognize and attach to the chromophores. "The DNA recognizes the dye molecules, and then the system spontaneously self-assembles," Choi said.
The new technology could lead to photoelectrochemical cells that can operate at full capacity indefinitely as long as new chromophores are added, the researchers say.