What is Photovoltaic or Solar Cell? – Construction, Working and Advantages

An electrical device which converts light energy into electrical energy through the photovoltaic effect is known as photovoltaic cell or PV cell or solar cell. A photovoltaic cell is basically a specially designed p-n junction diode.

Construction and Working of Photovoltaic Cell

The construction of a photovoltaic cell is shown in the following figure.

A photovoltaic cell consists of a base metal plate and it is made of either steel or aluminum over which a metallic selenium layer is situated which is light sensitive and acts as the positive terminal.

An electrically conducting layer of cadmium oxide is applied by sputtering over the selenium layer. This cadmium oxide layer is sufficiently thin in order to allow light to reach the selenium and as it is electrically conducting, hence acts as the negative terminal. A strip of metal sprayed on the edge of the top surface which forms the negative contact.

The transparent varnish layer is used to protect the front surface of the photovoltaic cell.

When light falls on the surface of selenium layer through the layer of cadmium oxide, the selenium compound releases the electrons that are sufficient to maintain the flow of current through the external circuit connected between the positive and negative terminals.

Advantages of Using Photovoltaic Cells

The advantages of using photovoltaic cells are listed below −

• Photovoltaic cells do not cause pollution while producing electricity.

• The operating cost of photovoltaic cells is low as source of energy is natural light.

• The maintenance cost of PV cells is also minimum as they need little maintenance.

• Photovoltaic cells have long lifespan. They are highly reliable.

• PV cells are the best renewable energy sources.

Disadvantages of Photovoltaic Cell

Following are some of the disadvantages of using photovoltaic cells −

• The operation of photovoltaic cells depends upon the light energy of the Sun, thus their operation depends upon the weather.

• Storage of electricity produced by the photovoltaic cells is expensive and complicated.

• They require more space for installation.

Applications of Photovoltaic Cell

The applications of photovoltaic cells include the following −

• Remote lighting systems

• Emergency power

• For Satellites power supplies

• In photometric measurements

• As portable power supplies such as solar car, etc.