Tuesday, January 21, 2014: MIT scientists are testing solar cells with a layer of carbon nanotubes, making it possible to take advantage of wavelengths of light that ordinarily go to waste. It’s tough to build solar cells that capture both heat and light. However, researchers at the Massachusetts Institute of Technology have blown past that limitation with a prototype chip.
MIT scientists have combined carbon nanotubes, hollow cylinders with walls that are one-atom thick, with photonic crystals to create an ‘absorber-emitter’. When the nanotubes absorb concentrated sunlight, their temperature rises, heating the device to as much as 962 degrees Celsius. The tubing heats up photonic crystals so much that they glow with an intense light, giving an attached solar cell more energy than it would collect through sunlight alone.
Standard polysilicon photovoltaic cells don’t respond to the entire spectrum of sunlight, limiting the amount of photons they’re able to convert into electricity. Standard polysilicon has a theoretical maximum efficiency of 33.7 per cent. However, the nanotube technology may be used to surpass that limit. The technology is already efficient enough to extract 3.2 per cent of the energy it gets, and MIT believes that it could reach 20 per cent with more development.
It might not be more effective than conventional technology, but it’s much easier to store heat than electricity; therefore a future nanotube-based panel could provide a lot more on-demand energy than we typically get today.
