fotovoltaic

Photovoltaic energy, or photovoltaic power, refers to the conversion of sunlight directly into electricity using semiconductor devices known as solar cells. The term photovoltaic is standard in English, though the spelling fotovoltaic is used in some languages. When light strikes a PV cell, photons excite electrons, creating electron-hole pairs that are separated by an internal electric field at a p-n junction or a similar structure. The resulting flow of electrons through an external circuit provides electric current.

Most PV devices are made from silicon, arranged in cells, modules, and arrays. Crystalline silicon comes in monocrystalline and polycrystalline forms, while thin-film technologies use materials such as cadmium telluride, amorphous silicon, and copper indium gallium selenide. Emerging technologies include perovskite cells and tandem configurations that stack layers to exceed single-junction efficiency.

PV systems range from small rooftop installations to large utility-scale plants. Key components include modules (collections of cells), inverters to convert direct current to alternating current, mounting structures, and balance of system equipment. PV is widely used for residential, commercial, and industrial electricity, as well as remote or off-grid power.

The photovoltaic effect was first observed in 1839 by Alexandre-Edmond Becquerel. Practical silicon solar cells were developed in the 1950s, and costs have fallen dramatically since the 2000s due to manufacturing advances and economies of scale. Today PV is a major source of new electricity capacity in many regions, aided by policy incentives and market competition.

PV generation is clean at the point of use, but it is intermittent and requires integration with storage or grid management. Lifecycle considerations include land use, manufacturing energy, and end-of-life recycling. The levelized cost of energy for PV has declined substantially, improving competitiveness with conventional power.