The new cell captures energy from the near-infrared region of the spectrum and is built entirely out of carbon nanotubes.
The possibility of incorporating this technology into existing solar systems is what sets it apart and makes it rather interesting. Being able to add even a few percentage points to a standard system would amount to a significant boost in efficiency – especially as existing systems deteriorate over time. The key, of course, will be improving their production techniques while keeping costs to a minimum.
The MIT solar cells use single-walled nanotubes constructed from C60 arranged symmetrically. They are transparent to visible light, which would allow them to be placed on top of conventional silicon solar cells (which are unable to harvest near-infrared). The nanotubes are stable in air, so they do not require a polymer layer to hold them in place – a crucial part in the production process of other nano-tube-based solar cells.
At this point, the technology is at the proof of concept stage and results have not been especially impressive. The 0.1 percent efficiency will need to improve rather dramatically if they are ever to see production – but the team believes that they have identified sources of inefficiency and will be able to improve on that figure.