Solar Panel

A solar panel is a device that converts sunlight into electricity, built from an assembly of individual photovoltaic cells wired together into a module and grouped further into larger panel arrays. Each photovoltaic cell is made of a light-sensitive semiconductor material that releases energized electrons when struck by sunlight, and those electrons flow through an external circuit as direct current, which can power a device directly or charge a battery. The underlying photovoltaic effect was first observed in 1839, but the technology only became commercially practical in 1954, when Bell Labs built the first viable silicon solar cell, building on cell designs developed between 1939 and 1941. Solar panels are now deployed at every scale, from residential rooftops to vast utility-scale solar farms, and in many regions have become cost-competitive with fossil-fuel generation, though their output still depends on available sunlight.