How Solar Panels Make Electricity

The Science of Photovoltaics

Also known as PV, photovoltaics is a process of generating electrical power by converting solar radiation from the sun, into electricity by using semiconductors. The photovoltaic effect is the production of an electric current in a material with light exposure. This effect is caused when light photons excite electrons to a higher energy state, which causes them to act as charge carriers for an electric current.

Silicon in Photovoltaics

Although other materials are also used in the production of solar modules, silicon is used in the majority of solar modules produced. Silicon is an abundant raw material found in sand. Silicon has four electrons in its outer shell, but it has the capacity to hold eight. When silicon atoms share these four electrons with other silicon atoms, the capacity of eight is filled. This causes silicon atoms to develop a strong, stable bond. This structure is known as pure, crystalline silicon.

Pure silicon is a poor conductor of electricity, because there are no free electrons available to act as carriers. Therefore, the silicon used in PV cells is combined with additional elements that have five electrons. These additional electrons, referred to as free carriers, carry an electrical current.

Solar Panel Construction

Solar panels are made up of electrically interconnected solar cells. The solar cells are thin slices of silicon which is a semiconductor material. The cells are connected to one another in a string which carries the electric current. The solar panel is usually made up of four different rows of cell strings. The entire panel is covered by non-reflective glass and robust backsheets in order to protect the delicate cells from environmental damage.

The electricity from the strings is then routed to the solar panel junction box, which is located on the back of the solar panel. After traveling through the junction box the power flows to the inverter, which transforms the power into AC electrical power that can be used in your home.