Seen as an alternative energy solution to oil for a number of decades, solar panels dot roadside signs, stretch through miles of solar farms, cover rooftops, and help power the International Space Station. But how do they work?
Solar panels work by allowing light particles, or photons, to separate electrons from atoms, creating a flow of electricity. The panels themselves are made of many, smaller groups called photovoltaic cells. (Simply put, they make sunlight into electricity.) A collection of those cells joined together form a solar panel.
Photovoltai cells are typically made of silicon, the materials used in microelectronics. To work, these cells need to create an electric field. Just like a magnetic field works using opposite polls, the separation of opposite charges create and electric field. In order to achieve this field, other materials are mixed with the silicon by manufacturers, giving each “sandwich slice” a negative or positive electrical charge.
Negatively charged phosphorous is added to the top layer of silicon, adding extra electrons, to that layer. Concurrently, positively charge boron is added to the bottom layer, resulting in fewer electrons. All of this creates an electrical field between the silicon layers. Once sunlight hits the panel it sets an electron free and the electrical field created by the silicon layers pushes that electron out of the junction.
A few other pieces of the cell turn electrons into power usable by the electrical company. Conductive metal plates on the sides of the cell gather electrons and move them to wires. Electrons can flow like any other source of electricity at this point.
There are, of course, other kinds of solar power technology – including concentrated solar power (CSP) and solar thermal – that promote panels different than the typical photovoltaic cell panels, but still convert sunlight into either heat air or water or create electricity.