Nanoparticles enhance plastic solar cell efficiency
Researchers all over the world are racing to bump up the efficiency of plastic solar cells, and, thus far, physicist David Carroll of Wake Forest University appears to be in the lead.
Last year, Carroll and his team approached 5% efficiency with these cells, nearly 2% more than other cells at the time. Now, Carroll and his team report online, on April 19 in Applied Physics Letters, that they have achieved another 20% increase, bringing the total efficiency to more than 6%.
Photovoltaic or solar cells—devices that convert solar energy into electricity—have powered everything from wristwatches and calculators to satellites and space probes for several decades. Made mostly from silicon crystals, they are energy-efficient. However, they are expensive, and their production is complicated. Consequently, researchers have been turning to plastics for their low cost, flexibility, and light weight. But plastic solar cells are inefficient and, until now, were far away from the minimum of 8% efficiency required for commercial use.
Previous research revealed that embedding carbon nanoparticles into plastic solar cells can enhance their photoabsorption and electrical conductance. Carroll and colleagues kept tweaking the conditions under which the nanoparticles were introduced into the plastic to see how they changed the efficiency of the cells. By using a temperature at which the nanoparticles form tiny crystals (as opposed to large ones), they were able to form "nanowhiskers" inside the plastic, which boosted the efficiency to 6.1%. Carroll hopes to hit the 10% efficiency mark in another 2 years.
