Question

Which of the following elements is used in making solar cells?
A. Gold.
B. Carbon.
C. Silicon.
D. Silver

Answer 1

Hint: The device used to convert solar energy into electrical energy is known as solar cell. It is based on photovoltaic effects. Photoelectric effect is defined as the generation of voltage due to the bombardment of light photons. Pure silicon which is crystalline in nature is a poor conductor of electricity as it is a semiconductor material at its core.

Complete step by step answer:
Solar cells contain a p-n junction diode which is usually made of Si and GaAs.
The element used in making solar cells is silicon.
The correct option is C.

So, the correct answer is “Option C”.

Additional Information:
Material used in fabrication of solar cells.
The material with band gap 1.5 e.V are ideal material for this purpose.
The important criteria for the selection of a material for solar cell fabrication are:
1. Band gap
2. High optical absorption
3. Electrical conductivity
4. Availability of the raw material.
5. Cost factor.
Advantages of solar cells are:
1. Pollution free.
2. Long lasting.
3. Maintenance free.
They can be used anywhere as a self-generating source of electricity. But solar cells have a high cost of installation and low efficiency.

Note:
When light photons reach the silicon junction, they excite electrons from the valence band to conduction band, leaving behind equal no. of holes in the valence band. These electrons –holes pairs generated in the depletion region move in opposite directions due to the barrier field. Photo generated electrons move towards the n side and holes towards the p side. The collection of these charge carriers makes p-side a positive electrode and a n side a negative electrode. Hence a photo voltage is set up across the junction.

Uses of solar cells:
We can use the solar cells to charge the batteries for power during light.
Spacecrafts make use of arrays of solar cells or solar panels to provide electrical energy.