Question

Explain the construction and working of the solar cell.

Answer 1

Hint: A solar cell is a device which converts light energy into electrical energy. It is a semiconductor device which allows conduction of current when light is shown on it, due to its p-n junction.

Complete step by step answer:
A solar cell can also be known as a photovoltaic cell. It can be defined simply as a device which allows the conversion of light energy to electrical energy through the photovoltaic effect. In essence the solar cell is a pn junction diode in which its current voltage and other characteristics may vary when exposed to light.
Construction of a solar cell – usually a somewhat thick layer of n-type semiconductor is layered by a thin layer of p-type semiconductor. Then electrodes are placed on the top of the p-type semiconductor. Another electrode for collecting current is attached to the bottom of the n-type semiconductor. Then a thin glass is used to enclose the setup to prevent direct mechanical stress to the semiconductor.
Working principle, when light strikes the surface of the cell, it penetrates to the pn junction created by the fusion p-type semiconductor and the n-type semiconductor. The photons are able to create electron-hole pairs. Free electrons in the depletion region will then migrate to the n-type semiconductor, similarly, the holes from the depletion region will migrate to the p-type. Two charges build up on the opposite side of the junction, we have a potential difference across the junction. Hence if load is connected across them, current will flow through it.

Note:
For clarity, when the n-type and p-type conductors are building charges, these charges will tend to repel each other to the opposite side. However, either charges will be unable to cross due to the barrier potential.