Definition of solar cell Solar cell is that cell which converts light energy to electrical energy. Working principal of solar cell is related to emission of light or absorption. It is an electronic device. Actually solar cell is p-n junction device which convert solar energy to electrical energy.
How solar cell work
A figure shown of the construction of solar cell. It is a p-n junction. N-type substrate is the base or foundation. On the top a thin layer of p-type semiconductor is formed by diffusion process. A window of glass or plastic remains with p-type layer. From this light can enter into p-type layer. P-type layer is made as so thin as the light can easily pass into upper surface most of light is gone through the p type layer and small amount of light reflects from the surface. Light photons reach the p-n junction. Due to collision of these photons with the valence electrons, the valence electrons acquire sufficient energy and these electrons are ejected from the parent atoms. Such way holes and electrons are generated on both the sides of the junction and flowing of them creates current. The generated current amount depends on the width of the illuminated region and the energy of light. A solar panel contains series-parallel combinations of solar cell.
Uses of solar cell
(i) It is used in calculators which requires small current.
(ii) Solar cells are used for supplying power to different electrical and electronic equipment in a satellite.
(iii) Solar cell works in home which is larger and can supply huge electrical energy.
(iv) At remote places, sensors are used for measuring different quantities like temperature, humidity etc. A solar panel supplies necessary power to the equipment and circuits.