A solar panel is a collection of photovoltaic cells, and is also known by the moniker photovoltaic module. In turn, a collection of solar panels is called a solar or photovoltaic array. The cells in a solar panel are comprised of an encapsulate (typically glass or clear plastic), a conducting contact grid, and two semiconductors.
A solar panel produces electricity through the photo-voltaic effect. The embedded solar cells in the solar panel convert the energy from the photons of light that strike the panel into usable DC current. Photons that contact the panel have different wavelengths along the solar spectrum, and solar panels are designed to absorb the energy of photons across specific wavelengths.
Solar panels are composed of layered semiconductors. When a photon of light energy is absorbed by the solar panel and enters an atom located on the surface of one of the solar cells, the newfound energy of the atom permits the atom's electron to flow. Specifically, the electrons diffuse across the solar panel's p-n junction, the point between a p-type semiconductor (base) and an n-type semiconductor (emitter). As the solar panel collects energy, a negative charge is generated in the emitter because of the increased electron count, and a positive charge is generated in the base because of the increased electron hole count. As freed electrons from the emitter and electron holes from the base cross the junction, an electrical field applied to the solar panel sweeps them away to an external load, generating direct current.
For more information on how solar panels are made, see our section concerning Solar Panel Production.
In this solar panel diagram, electrons from the emitter and electron holes from the base are diffused into the electric field, which when attached to an external load, generates current.
A Solar Panel installation can generate electricity for both on and off-grid projects. Solar panels can be placed wherever there is an abundance of direct sunlight. Solar panels are often mounted on RV's, watercraft, residential rooftops, and in urban areas larger commercial arrays are becoming increasingly common. If you want to learn more about installing your solar panel, see our installation section.