Bell Labs’ first practical solar cell, demonstrated in 1954, was made from silicon.
Researchers Daryl Chapin, Calvin Fuller, and Gerald Pearson developed the device in New Jersey. Their cell converted sunlight into electricity at an efficiency of about 6%, a major improvement over earlier selenium cells. The work helped establish photovoltaic power as a practical technology rather than merely a laboratory curiosity.
Silicon became dominant because it is abundant, stable, and has useful semiconductor properties. Modern crystalline-silicon cells are usually either monocrystalline or polycrystalline, although thin-film technologies use materials such as cadmium telluride and copper indium gallium selenide.
A common mix-up is confusing the first practical silicon cell with the first observation of the photovoltaic effect, which dates to Alexandre-Edmond Becquerel’s 1839 experiment. Bell Labs’ achievement was the creation of a useful silicon device capable of producing meaningful electrical power.