A Photovoltaic (PV) solar cell generates electricity from sunlight through the photovoltaic effect, a process that converts light energy into electrical energy. PV solar cells are typically made from semiconductor materials, such as silicon, that have specific electronic properties.
Here's how the photovoltaic solar cell works:
Absorption of Sunlight: When sunlight (photons) strikes the surface of the solar cell, it is absorbed by the semiconductor material. The sunlight provides energy to the electrons within the semiconductor.
Generation of Electron-Hole Pairs: The absorbed energy causes some of the electrons in the semiconductor's valence band to gain enough energy to break free from their atoms, leaving behind positively charged "holes" in their place. These free electrons and holes can move independently within the material.
Separation of Charge Carriers: Due to the internal electric field present within the semiconductor material (which is usually created by the specific design of the cell), the free electrons are pushed towards the n-type (negative) side of the cell, while the holes are pushed towards the p-type (positive) side.
Electric Current Generation: The separated charge carriers create an electric potential difference between the two sides of the solar cell, which leads to the flow of electrons from the n-type side to the p-type side through an external circuit. This flow of electrons is what we know as an electric current.
Capturing Electricity: As the electric current flows through the external circuit, it can be harnessed to power electrical devices, charge batteries, or even feed electricity back into the grid.
Recombination: To maintain the photovoltaic effect, it's crucial to prevent the recombination of electrons and holes. This is achieved through the careful design and construction of the solar cell to minimize losses caused by recombination.
It's important to note that a single solar cell typically produces a relatively small amount of electrical power. To generate more significant amounts of electricity, multiple solar cells are connected to form a solar panel, also known as a PV module. These panels can be combined into larger arrays to meet the power requirements of residential, commercial, or industrial applications.
Photovoltaic solar cells are a crucial technology in harnessing renewable energy from the sun and play a vital role in sustainable energy production.