How Solar Cells convert Sunlight into Electricity ???

Looking into the history Alexandre-Edmond Becquerelin 1839 witnessed the first observation of Photovoltaic effect. Russel Ohl in 1946 invented the first modern solar cell made up of silicon. “Photo” means pertaining to light and “Voltaic” means producing voltage. After 100 years of research, the conversion of sunlight to electricity is not just an experiment but much more. Latest PV technologies are based on the electron-hole creation principle in each cell having two different material layers (P-type and N-type) semiconductor which are separated by a junction. As seen in the figure, when a photon from sunlight strikes the semiconductor, free electrons and holes with higher energies are created. An electric field is required for inducing these higher energy electrons and holes to flow out of the semiconductor and do the useful work. In solar cells, this is done by using p-n junction as it is known that an electric field exists across p-n junction and by this electrons are swept in one direction and holes in another.