What is a Photovoltaic?

Photovoltaic array

Photovoltaics is the base science  behind how we harness solar energy. It is the process that converts sunlight into electricity. First observed in 1839, the photovoltaic effect wasn’t understood until 1954 when scientists at Bell Telephone discovered that silicon (an element found in sand) created an electric charge when exposed to sunlight.

Traditional solar cells are made from silicon, are usually flat-plate, and generally are the most efficient. In a photovoltaic cell, sunlight detaches electrons from their host silicon atoms. Tiny packets of light energy called photons are captured by electrons, and impart enough energy to kick the electron free of its host atom. Near the upper surface of the cell is a “one way membrane” called a pn-junction. The pn-junction is formed by diffusing tiny quantities of phosphorus to a depth of about one micrometre into a thin wafer of silicon.

When a free electron crosses the pn-junction it cannot easily return, causing a negative voltage to appear on the surface facing the sun (and a positive voltage on the rear surface). The front and rear surfaces can then be connected together via an external circuit in order to extract current, voltage and power from the solar cell.

Second-generation solar cells are called thin-film solar cells because they are made from amorphous silicon or non-silicon materials such as cadmium telluride. Thin film solar cells use layers of semiconductor materials only a few micrometers thick. Because of their flexibility, thin film solar cells can double as rooftop shingles and tiles, building facades, or the glazing for skylights.

 

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  1. […] to achieve carbon neutrality on its energy use and will have all of its energy needs met by solar photovoltaics (solar […]

  2. […] Currently uses solar photovoltaic systems in 100 warehouses in Arizona, California, Colorado, Hawaii, New Jersey, New Mexico, New […]

  3. […] Photovoltaics is the base science  behind how we harness solar energy. It is the process that converts sunlight into electricity. First observed in 1839, the photovoltaic effect wasn’t understood until 1954 when scientists at Bell Telephone discovered that silicon (an element found in sand) created an electric charge when exposed to sunlight. […]

  4. […] owners for the electricity they add to the grid. For example, if a residential customer has a photovoltaic (PV) system on the home’s rooftop, it may generate more electricity than the home uses during […]

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