Photovoltaics, or PV for short, is a solar power technology that uses solar cells or solar photovoltaic arrays to convert energy from the sun into electricity. Photovoltaics is also the field of study relating to this technology.

Solar arrays are increasingly incorporated into new domestic and industrial buildings as a principal or ancillary source of electrical power. Typically, an array is incorporated into the roof or walls of a building, roof tiles can now even be purchased with an integrated PV cell. Arrays can also be retrofitted into existing buildings; in this case they are usually fitted on top of the existing roof structure. Alternatively, an array can be located separately from the building but connected by cable to supply power for the building.

The largest installations are grid-connected systems. These systems are connected to the utility grid through a direct current to alternating current (DC-AC) inverter. When the load required in the building is more than that supplied by the PV array then electricity will be drawn from the grid; conversely when the PV array is generating more power than is needed in the building then electricity will be exported to the grid. Batteries are not required and standard AC electrical equipment may be used.

There are many research institutions and departments at universities around the world who are active in photovoltaics research. Countries which are particularly active include Germany, Spain, Japan, Australia, China, and the USA. 

A solar cell (or a "photovoltaic" cell) is a device that converts photons from the sun (solar light) into electricity. In general, a solar cell that includes the capacity to capture both solar and nonsolar sources of light (such as photons from incandescent bulbs) is termed a photovoltaic cell. Fundamentally, the device needs to fulfill only two functions: photogeneration of charge carriers (electrons and holes) in a light-absorbing material, and separation of the charge carriers to a conductive contact that will transmit the electricity. This conversion is called the photovoltaic effect, and the field of research related to solar cells is known as photovoltaics.

Solar cells have many applications. Historically solar cells have been used in situations where electrical power from the grid is unavailable, such as in remote area power systems, Earth orbiting satellites or space probes , consumer systems, e.g. handheld calculators or wrist watches, remote radiotelephones and water pumping applications. Recently solar cells are particularly used in assemblies of solar modules (photovoltaic arrays) connected to the electricity grid through an inverter, often in combination with a net metering arrangement. 

Solar cells are regarded as one of the key technologies towards a sustainable energy supply.The term solar panel is best applied to a flat solar thermal collector, such as a solar hot water or air panel used to heat water, air, or otherwise collect solar thermal energy. But 'solar panel' may also refer to a photovoltaic module which is an assembly of solar cells used to generate electricity. In all cases, the panels are typically flat, and are available in various heights and widths.

An array is an assembly of solar-thermal panels or photovoltaic (PV) modules; the panels can be connected either in parallel or series depending upon the design objective. Solar panels typically find use in residential, commercial, institutional, and light industrial applications.

Some universities and institutes which have a photovoltaics research department:

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Deployment of solar power depends largely upon local conditions and requirements. But as all industrialised nations share a need for electricity, it is clear that solar power will increasingly be used to supply a cheap, reliable electricity supply. In 2004 the worldwide production of solar cells increased by 60% but silicon shortages reduced growth afterwards.Every technology causes some amount of harm to the environment. Unlike fossil fuel based technologies, solar power does not lead to any harmful emissions during operation, but the production of the panels leads to some amount of pollution. 

Renewable energy (Non-Conventional Energy) is defined as "energy derived from resources that are regenerative or for all practical purposes can not be depleted." Renewable energy sources contribute approximately 29.3% of human energy use worldwide. The prime source of renewable energy is solar radiation, i.e. sunlight. The Earth-Atmosphere system supports approximately 5.4 x 1024 joules per year in the solar radiation cycle (Sorensen, 2004). Non-renewable is the opposite of renewable.

Mankind's traditional uses of wind, water, and solar power are widespread in developed and developing countries; but the mass production of electricity using renewable energy sources has become more commonplace only recently, reflecting the major threats of climate change due to pollution, exhaustion of fossil fuels, and the environmental, social and political risks of fossil fuels and nuclear power. Many countries and organizations promote renewable energies through taxes and subsidies. Varying definitions of the term renewable energy have been adopted to define eligibility under these policies.