The story of solar cells goes back to an early observation of the photovoltaic effect in 1839. French physicist Alexandre-Edmond Becquerel, son of physicist Antoine Cesar Becquerel and father of physicist Henri Becquerel, was working with metal electrodes in an electrolyte solution when he noticed that small electric currents were produced when the metals were exposed to light, but he couldn’t explain the effect.
Bell Labs announced the invention on April 25, 1954 in Murray Hill, New Jersey. They demonstrated their solar panel by using it to power a small toy Ferris wheel and a solar powered radio transmitter.
Those first silicon solar cells were about 6 percent efficient at converting the energy in sunlight into electricity, a huge improvement over any previous solar cells.
According to wikipedia