"Organics are generating lots of excitement because of the possibility that they could be manufactured at very low cost from abundant materials," says Ginger, whose paper was co-authored by Washington researchers Liam Pingree and Obadiah Reid, and appeared online last month at the American Chemical Society journal Nano Letters.
Despite their projected low cost, the efficiency of solar cells made from organic thin films have a long way to go to catch with other technologies in use and under development. Some silicon-based solar cells have achieved greater than 40 percent efficiency in the lab.* Meanwhile, University of California, Los Angeles, researchers report having achieved 9.13 percent efficiency using solar cells made from copper indium gallium selenide (CIGS), and are optimistic that they will reach their goal of 15 percent or 20 percent.
Massachusetts Institute of Technology mechanical engineering professor Emanuel Sachs claims to have found incremental ways to boost the amount of electricity that common photovoltaics generate from sunlight without increasing the costs. A year ago, he said he raised the conversion efficiency of test cells made from multicrystalline silicon from the typical 15.5 percent to nearly 20 percent—on par with pricier single-crystal silicon cells.
Such improvements could bring the cost of PV power from the current $1.90 to $2.10 per watt down to $1.65. With additional tweaks, Sachs anticipated creating within four years solar cells that could produce electricity at a dollar per watt, a feat that would make electricity from the sun competitive with that from coal-burning power plants.
* Note (8/07/09): National Renewable Energy Laboratory researchers in Colorado were able to achieve 40.7 percent efficiency, but this required the use of light-concentrating devices, such as miniature plastic lenses and mirrors. More conventional silicon chips do not exceed 30 percent efficiency.