Photovoltaics is a method of converting light into electricity. This involves the use of materials that exhibit the photovoltaic effect.
The photovoltaic effect was first observed by the French physicist, Edmund Bequerel, in 1839. He found out that certain materials could absorb light and produce a weak electric current. This happens when sunlight or any other light is absorbed by a photovoltaic material. The photons excite the electrons, creating a flow of electrons, which is then converted into electricity. In 1905, Albert Einstein published a paper describing the nature of the photovoltaic effect. This led to the quantum revolution. Einstein earned a Nobel Prize for his work.
Photovoltaics was not fully developed until the 1960s. The use of photovoltaic materials or solar cells, mainly made of silicon or platinum, was very expensive. The first application of photovoltaic technology was powering spacecrafts and satellites.
Today, there are numerous applications of photovoltaic technology. Devices such as calculators, GPS units and chargers are equipped with solar cells. There are also buildings and cars that are solar powered. Other applications of photovoltaics include traffic lights, water pumps, solar bulbs, emergency telephones and trash compactors.
Due to the increased demand for renewable energy, photovoltaic technology has improved dramatically. There are already numerous photovoltaic power stations worldwide which provide power at a utility level. They are sometimes called solar farms or solar ranches.
More than 100 countries have installed solar farms. Globally, at least 160 billion kWh is produced in 2014. This represents about 0.85% of the global electricity demand.