An interesting effect has been observed in silicon nanocrystals. It’s called “Multiple Exciton Generation” or (MEG). It results in the formation of more than one electron per absorbed photon.
The MEG effects have been previously observed in non-commercial silicon products, which are environmentally harmful (such as those containing lead). However, this new discovery would allow the traditional silicon-based solar cell makers to integrate a new facet to their manufacturing process to take advantage. This is a key component in making the solar cell industry a viable alternative to the “more traditional” sources of energy. If they can use the tools that they have, while increasing the efficiency, it would be wonderful.
Silicon solar cells with efficiencies in the low 40% range are readily made today. It is anticipated that 63% efficiencies would be found within 12 years. One of the biggest limitations today is that about 50% of the received sunlight energy is lost as heat. With MEG, some of that heat energy can be converted into electricity at the 420 nm (and below) wavelengths.
Plastic solar cell technologies have also been discovered recently, which are expected to achieve 15% efficiencies in 2010. The advantages plastic solar cells have over silicon are a much lower manufacturing expense, they’re far more durable, more flexible, and are capable of being more readily integrated into permanent structures in an eye appealing manner.
Read more at NREL Newsroom, and post your thoughts below.