Photovoltaic (PV) devices generate electricity directly from sunlight through an electronic process that occurs naturally in certain types of materials, called semiconductors. The electrons in these materials are released by solar energy and can be induced to travel through an electrical circuit, powering electrical devices or returning electricity to the grid.
PV devices can be used to power small appliances such as calculators, to homes and large commercial buildings.
How does PV technology work?
The photons strike and ionize the semiconductor material in the solar panel, releasing the protons from their atomic bonds. Due to the structure of semiconductors, electrons are forced in one direction, causing electric current to flow. Solar cells are not 100% effective in crystalline silicon solar cells, partly because only certain light within the spectrum can be absorbed. Some light is reflected, infrared is too weak to generate electricity and ultraviolet creates thermal rather than electrical energy.
History of photovoltaic technology
The PV effect was observed in 1839 by Alexandre Edmund Becquerel and was the subject of scientific research during the early 20th century. In 1954, Bell Laboratories, USA, introduced the first PV device that produced a useful amount of electricity and by 1958, solar cells were being used in a variety of scientific and commercial applications.
For years, the high cost of the technology made large-scale application impractical, but advances in industry and research in more recent times have made PV devices more feasible, and even today we continue to experience a cycle of increasing production and decreasing prices.
Today there are thousands of panel models available from hundreds of companies.