Solar cells use a semiconductor to convert the solar energy of sunlight into electricity via the photovoltaic effect. Individual cells are assembled in order to form solar panels and arrays. First observed by French physicist Alexandre-Edmond Becquerel, son of electricity pioneer Antoine Cesar Becquerel, as a teenager in 1839, the photovoltaic effect is the process by which voltage or electric current is created in a material that has been exposed to electromagnetic radiation (such as light). The first solar cell was built in 1883 by American inventor Charles Fritts, who coated selenium (a semiconductor) with a thin layer of gold. The solar cell worked but had an efficiency of only about 1 percent, making it impossible to generate enough electricity to recover the cost of ...