A solar cell is an electrical device which converts sunlight into electricity by a method called the photovoltaic effect. A solar cell is made up of semiconductor materials of which silicon is the most commonly used. Solar cells are being extensively used today in calculators, satellites and for power generation.

 

When sunlight consisting of energised particles called photons hit surface of a solar cell, they transfer their energy to the valence electrons in the silicon cell. Due to the electric field existing in the cell between the 2 different types of silicon, N-type (which has an excess of electrons) and P-type (which misses electrons and hence have holes in their place), there is a flow of electrons which constitute a current. This is how a solar cell produces electricity.

The process of solar energy conversion can be explained as follows:

Solar cells can be classified broadly into two types:

1.Crystalline Solar Cells, made mainly from silicon. These can in turn be of two types:

• Monocrystalline
• Multicrystalline (also called Polycrystalline)

2.Thin Film Solar Cells

• Thin film cells are made from a variety of semiconductor materials, including Silicon, CIGS (Copper Indium Gallium Selenide), CIS (Copper Indium Selenide), and CdTe (Cadmium Tellurium)

Today, monocrystalline silicon cells are the considered the most efficient. But in order to reduce costs, polycrystalline silicon is being increasingly used in spite of a reduction in efficiency.