Photovoltaics are devices that convert light into electricity throught the photoelectric effect -- a quantum phenomenon in which an electron is ejected from an atom or group of atoms upon absorbing a photon. The most common type of photovoltaics are cells made from thin slices of bulk silicon ingots. However, photovoltaics have been created from a variety of semiconductor materials using a number of different manufacturing processes.
The efficiency of a photovoltaic cell, module, or panel can be measured in the same way as the efficiency of any solar electric generating system that has a measurable footprint: by dividing the output power in kilowatts by the footprint area in square meters.
Currently-available photovoltaics range in efficiency from a few percent to just over fourty percent. 1
|Credit: Lawrence Kazmerski, Don Gwinner, Al Hicks, 11/11/07|