Solar cells are commonly characterized by the percentage of the incident solar light that they can convert into electrical power. Thus, the efficiency is given as a percentage. In general, the efficiency is determined by the material from which it is made and by the technology used to construct the solar cell. Efficiencies for commercially available solar cells range from about 5% to about 17%. Although inorganic-based solar cells have reached a maximum efficiency of up to 40%, these are expensive to produce and polluting when thrown away. The maximum efficiency reached for an organic-based solar cell is around 6% as of 2007. Therefore, there is still a lot of work to be done to improve them.
If researchers could find an organic-based solar cell whose efficiency reached 10%, these would be commercially feasible and would revolutionize the field of solar materials. Additionally, if these cells covered 0.16% of the surface of the planet, they would produce about an additional 20 TW (Terawatts, a trillion Watts), which will make up for the estimated increase in energy for the year 2050.