Solar Cells
A solar cell, also known as a photovoltaic cell, is an electronic device that converts the energy of light directly into electricity through the photovoltaic effect. It is a form of photoelectric cell, and multiple solar cells in an integrated group constitute a solar photovoltaic panel or module. Solar cells are typically made of semiconducting materials, such as silicon, that have been fabricated into a p–n junction. When light shines on a solar cell, the semiconductor material absorbs the sunlight, dislodging electrons from the materials atoms. This creates an imbalance of electrical charge between the cells front and back surfaces, which in turn creates a voltage potential. When the conductors on the cell absorb the electrons and are connected in an electrical circuit to an external load, such as a battery, electricity flows through the circuit.
The majority of solar cells are fabricated from silicon, with increasing efficiency and lowering cost as the materials range from amorphous to polycrystalline to crystalline silicon forms. Silicon is the most common semiconductor material used in solar cells, representing approximately 95% of the modules sold today. Solar cells made out of silicon provide a combination of high efficiency, low cost, and long lifetime. Additionally, there are thin-film solar cells made by depositing one or more thin layers of PV material on a supporting material such as glass, plastic, or metal. These cells use materials like cadmium telluride (CdTe) and copper indium gallium diselenide (CIGS) .
Solar cells can be arranged into large groupings called arrays, which can function as central electric power stations, converting sunlight into electrical energy for distribution to industrial, commercial, and residential users. Solar cell panels are also used to provide electric power in many remote terrestrial locations where conventional electric power sources are either unavailable or prohibitively expensive to install. The material requirements for solar cells are feasible, as silicon is the second most abundant element in Earth’s crust. These factors have led to the envisioning of a future "solar economy" in which practically all of humanity’s energy requirements are satisfied by cheap, clean, renewable sunlight.
