A solar cell is an electrical device that converts light (photons) energy into electrical energy. The operating principle behind this is the diode action or photovoltaic effect. Many solar cells are generally connected to form a solar panel. These panels are designed to give a certain voltage and current ratings and associated power. The type of interconnections within the panel determines the total voltage or current based on the required application.

Solar cells are made of various semiconductor materials. Semiconductors are crystalline materials that conduct electricity when subjected to light or even heat. Semiconductor’s ability to conduct (conductivity) is known to be much lower than metals and higher than insulators. This conductivity can be controlled by adding trace amounts of impurities. The amount of impurities determine how conductive the material will be.

To generate diode action or photovoltaic effect a p-n junction is required. Adding trace amounts of impurities is also known as doping. Certain types of impurities produces n-type characteristic, and other types of impurities produce p-type materials.

When light falls onto the p-n junction semiconductor sandwich, free positive (holes or absence of electrons) and negative charge (electrons) carriers are created due to the photoelectrical effect. If the p-n junction sandwich is connected to an external circuit current flows through the circuit because of the free charges.

To read how solar cells work please click on the arrow.