In addition, the viruses make the nanotubes soluble in water, which makes it possible to incorporate the nanotubes into the solar cell using a water-based process that works at room temperature.
Prashant Kamat, a professor of chemistry and biochemistry at Notre Dame University who has done extensive work on dye-sensitized solar cells, says that while others have attempted to use carbon nanotubes to improve solar cell efficiency, "the improvements observed in earlier studies were marginal," while the improvements by the MIT team using the virus assembly method are "impressive."
"It is likely that the virus template assembly has enabled the researchers to establish a better contact between the TiO2 nanoparticles and carbon nanotubes. Such close contact with TiO2 nanoparticles is essential to drive away the photo-generated electrons quickly and transport it efficiently to the collecting electrode surface."
Kamat thinks the process could well lead to a viable commercial product: "Dye-sensitized solar cells have already been commercialized in Japan, Korea and Taiwan," he says. If the addition of carbon nanotubes via the virus process can improve their efficiency, "the industry is likely to adopt such processes."
Belcher and her colleagues have previously used differently engineered versions of the same virus to enhance the performance of batteries and other devices, but the method used to enhance solar cell performance is quite different, she says.
Because the process would just add one simple step to a standard solar-cell manufacturing process, it should be quite easy to adapt existing production facilities and thus should be possible to implement rel
|Contact: Caroline McCall|
Massachusetts Institute of Technology