Genetically Modified Virus Improves Solar Cell Efficiency With Carbon Nanotubes
By James Mulroy
PCWorldApr 29, 2011 9:50 am PDT
Solar cells are about to get cheaper! Using a genetically modified virus called M13, researchers from MIT were able to make carbon nanotubes self-assemble allowing the solar cells to collect electrons at a more efficient rate. Scientists already know that single-walled carbon nanotubes have a high electron mobility, meaning that electrons can move through them very fast. Using this knowledge, researchers could in theory improve the efficiency of photovoltaic devices (like solar panels) using these nanotubes.
But there is one problem–carbon nanotubes, when they are formed, usually come in a mix of two types: Some of them act like semiconductors and some of them act like metals. If you know your chemistry, then you know that conductivity increases in metals when the temperature decreases, while conductivity actually increases in semiconductors as temperature increases (to a certain point, anyway). Because of this, the two types of nanotubes basically cancel each other out, making them less effective as a means of increasing solar cell efficiency.
The MIT researchers came up with a way to separate the two types so that they might be applied to a solar cell more effectively. The researchers used the M13 virus to rearange the carbon nanotubes on a surface. The virus also kept the tubes separated so they don’t cause circuits to, well, short-circuit.
You read that correctly. A virus rearranged the nanotubes. According to MIT, using this new process increased the solar cells’ efficiency by almost one third. Impressive! Check out Nature and MIT for the full details.