Photovoltaic cells or solar cells generate a voltage when radiant energy falls on the boundary between dissimilar substances. A solar panel, also called a photovoltaic panel, is a group of photovoltaic cells that are enclosed to keep the cells safe and so that the voltage obtained from each cell can be combined.
Photovoltaic cells are semiconductor devices that have a large-area photo cell diode that is capable of generating electric energy from sunlight. This conversion is called the photovoltaic effect. Photovoltaic cells are made from a semiconducting material, generally silicon crystal. When sunlight hits the photovoltaic panel, the light is absorbed by the silicon crystal. This absorption loosens the electrons from their atoms, causing the electrons to flow through the silicon crystal and generate electricity.
There are three basic types of photovoltaic cells: mono-crystalline cells, polycrystalline cells, and amorphous cells. A mono-crystalline cell is the most efficient, but also the most costly photovoltaic cell. A polycrystalline cell is more common and less expensive, but also less efficient. An amorphous cell is relatively inexpensive, but produces much less power. As such, the solar panels made from these photovoltaic cells must be larger to produce the same amount of energy. A UV sensitive photo cell converts UV radiation to electrical energy.
A photovoltaic system contains individual solar panels that can convert the solar energy into usable direct current (DC) electricity that can then be distributed through an inverter to the electric grid or the utility panels at industrial sites or even in houses. Photovoltaic cells are generally connected to form solar panels. Solar panels can also be combined to produce currents that can be used in a variety of applications.
Photovoltaic power is reliable, creates no pollution, and can be quickly installed. A photovoltaic cell manufacturer or a solar cells manufacturer can produce photovoltaic cells for many applications, ranging from calculators to satellites to telephones and vehicles. The expected lifetime for photovoltaic cells can be up to 40 years. The time to recoup the cost of a solar panel averages five years, but can range between one to thirty years depending on the type of solar panel and its larger photovoltaic system.