How a Photovoltaic cells Works - Electrical Engineering Gate

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Wednesday, January 2, 2019

How a Photovoltaic cells Works

Photovoltaics (or Solar Cells) are solid-state semiconductor devices that convert light into direct-current electricity. These semi-conductors are most commonly made out of silicon crystal, which are used in many electronics and computer components. The top layer of the silicon portion of a solar panel is made from a mixture of this silicon and a small amount of phosphorous, which gives it a negative charge. The inner layer, which constitutes the majority of the panel, is a mix of silicon and a little bit of boron, giving it a positive charge. The place where these two layers meet creates an electric field called a junction. When light (or photons) hits the solar cell, before it gets to the silicon crystal to make electricity it passes through a glass cover on the panel and an anti-reflective coating, which stops photons from reflecting off of the panel and being

 side view of a solar cell

lost. The photons are absorbed into the junction, which pushes electrons in the silicon out of the way (See illustration below). If enough photons are absorbed, the electrons are pushed past the junction and flow freely to an external circuit. When converted to Alternating Current electricity using what is called an inverter, this energy can be used to power anything that uses electricity.

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