How do solar cells work ?
Solar cells convert light energy into electrical energy either indirectly (by first converting it into heat) or through a direct process known as the photovoltaic effect. The most common types of solar cells are based on the photovoltaic effect. This happens when light falls on a two-layer semiconductor material and results in a potential difference, or voltage, between the two layers. The voltage produced in the cell is capable of driving a current through an external electrical circuit that can be utilised to power electrical devices. Solar cells are usually made from silicon, which is treated to release electrons-thereby generating an electric current-when light strikes it. Solar cell production increased by 50% in 2007, to 3,800 megawatts, and has been doubling every two years.
Solar cells are solid-state devices in which photons (or packets of light) collide with atoms. This process transforms the resulting energy into electrons. These electrons flow into wires connected to the cell, thus providing electrical current to appliances, lighting systems or other electrical loads; and all of the power comes directly from the sun.
