In this lecture, we are going to learn about the photovoltaic cell, its working, construction, principle of photovoltaic cell, advantages, and applications.
What is Photovoltaic Cell?
A photovoltaic cell is a specialized semiconductor device that operates on the principle of the photovoltaic effect.
What is Photovoltaic effect?
The photovoltaic effect is a process in which a light-sensitive semiconductor converts the visible light into a voltage or into a direct current.
- Some photovoltaic cells convert even infrared r ultraviolet radiation into direct current.
- The photovoltaic cells (PV) are usually made of silicon doped with other elements. New materials such as copper indium diselenide (CIS), gallium arsenide(GaAs), and cadmium telluride (CdTe) have also been developed for use in photovoltaic cells.
Circuit symbol of Photovoltaic Cell
Principle of Photovoltaic cell
- It is based on the principle of the photovoltaic effect.
- The photovoltaic effect is a process in which a light-sensitive semiconductor converts the visible light (sun light) into voltage. This action occurs in all semiconductors that are constructed to absorb energy.
Construction and working of Photovoltaic Cell
- In the construction of a photovoltaic cell (PV), two separate semiconductors are sandwiched together forming a p-n junction at the interface. In the device, although both materials are electrically neutral, n-type has excess electrons and p-type silicon has excess holes.
- The device is constructed in such a way that when the junction is exposed to visible light, a voltage difference is produced between the p-type and n-type materials. This is due to the flow of excess electrons from the n-type material to the p-type material, and the holes thereby vacated from p-type material flow towards n-type material.
- Due to these electrons and hole fowl, the two semiconductors act as a battery creating an electric field at the junction.
- Electrodes connected to the semiconductor layer, allow current to be drawn from the device which is proportional to the intensity of incident light.
Advantages of Photovoltaic Cells
- The photovoltaic cell does not require any external battery for its own operation, i.e. it is self-generating.
- Since solar energy is unlimited, once the photovoltaic system is installed, it can produce energy years together.
- The maintenance cost is minimum.
- It is non-polluting.
Application of photovoltaic cell
- The photovoltaic cells are used in low-power devices such as light meters.
- They are used in solar-powered scientific calculators.
- A large set of photovoltaic cells can be connected together to form solar modules, panels, or arrays.