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The solar cell is a part of semiconductor physics.   You may be very well aware of the p-n junction diode working. Then how LED works? With the help of the different LED’s, you had also determined the Planck’s constant.

Solar Cell an Introduction

In a layman language, you can say that solar cell converts sunlight into the electricity. This solar cell made by a p n-junction diode. To construct the Solar cells silicon, gallium arsenide, cadmium sulphide are mainly used. As you know that silicon shows the thermal properties. What is it means?

Thermal property means of the silicon material;  when electron and hole recombination takes place energy release in terms of the heat. Because of its silicon diode or any other device starts to heat up and you feel hot after some time.

On the other hand, gallium arsenide shows the optical properties when electron-hole recombinations take places. It means when electron-hole recombination takes place a photon emits. The principle of light-emitting diode (LED).

So, the solar cell also a p-n junction diode on which when sunlight falls it behaves like a battery, but how it works?  

Solar Cell Working

When sunlight falls on the p-n junction diode, photons are absorbed and electron-hole pairs are generated in p and n side of the diode.  The electron-hole pairs that are produced near to to the junction reach the space-charge region by the diffusion process.

Across the space-charge region, there is a strong barrier field that makes separated electrons and holes from a pair. So the electrons from p region move towards the n-region and same are true for the holes. They also move from the n-region towards the p-region.

By this process electron and holes accumulated across the junction and gives rise to a voltage. If any load is connected with the diode, a current will flow in the circuit. The current depends on the sunlight intensity directly.

Applications of Solar Cells

1. In satellites and space vehicles
2. Power supply for the household items