fotowoltik

Fotowoltik, or photovoltaics, is a method for converting sunlight directly into electricity using semiconducting materials that exhibit the photovoltaic effect. The most common material is silicon, and solar cells are assembled into modules that are then combined into larger arrays for rooftop systems, solar farms, or off-grid installations.

Photons from sunlight excite electrons in a semiconductor, creating electron-hole pairs. In a solar cell with a p-n junction, an internal electric field separates these charges, producing a direct current. A solar module provides a voltage and current, and an inverter converts DC to alternating current suitable for homes and the grid. Systems may include mounting hardware, wiring, grid interconnection equipment, and sometimes energy storage such as batteries.

Crystalline silicon technologies dominate, including monocrystalline and polycrystalline cells. Thin-film approaches (such as cadmium telluride, CIGS, and amorphous silicon) offer lower material use and different form factors. Module efficiencies commonly range from about 15% to 23% for commercial products, with higher-efficiency laboratory and specialized modules available. Performance declines at higher temperatures and under partial shading. Applications span residential rooftops, commercial installations, large-scale solar farms, and remote off-grid sites.

The photovoltaic effect was first described in the 19th century, with practical PV cells developed in the mid-20th century. Since the 2000s, global PV costs have fallen dramatically, contributing to competitive electricity prices in many regions. Economic metrics such as the levelized cost of energy (LCOE) are commonly used to compare projects. Operation emits no direct greenhouse gases, though manufacturing, transportation, and end-of-life recycling carry environmental impacts.