In a PV module, a solar cell serves as a crucial semiconductor element responsible for promptly converting light into electrical energy, producing direct current voltage and current.
Silicon solar cells are built by connecting silicon atoms to form a crystal lattice, providing a well-structured framework that enhances the efficiency of converting light into electricity.
Solar cells, also known as photovoltaic cells, are primarily designed to convert light into electricity. While they are not typically used to detect other electromagnetic radiation or measure light intensity, their primary function is to generate electrical energy from sunlight.
Solar cells are commonly grouped together to create solar modules, and these modules are further combined to form larger units like solar panels and solar arrays, which enable the generation of significant electrical power from sunlight.
Types of Solar Cells
There are three distinct types of solar cells, each possessing unique features.
1. 1st Generation Solar Cells
Approximately 90 percent of the world’s solar cells are manufactured using crystalline silicon wafers (c-Si). These wafers are obtained by slicing large ingots grown in meticulously clean laboratories, with the entire process taking up to a month to complete. The ingots can be in the form of single crystals, known as monocrystalline or mono-Si, or they may consist of multiple crystals, referred to as polycrystalline, multi-Si, or poly c-Si.
2. 2nd Generation Solar Cells
Classic solar cells are relatively thin wafers, usually measuring a fraction of a millimeter in depth (about 200 micrometers or 200μm). However, second-generation cells, also known as thin-film solar cells or thin-film photovoltaics, are incredibly thin, being about 100 times thinner again, with a depth of several micrometers or millionths of a meter.
While some of these cells are still made from silicon, they use a different form called amorphous silicon (a-Si), where atoms are randomly arranged instead of having a regular crystalline structure. Additionally, other materials such as cadmium-telluride and copper indium gallium diselenide are also used to make second-generation solar cells.
3. 3rd Generation Solar Cells
The latest solar cell technologies combine the advantageous features of both first and second-generation cells. Similar to first-generation cells, they exhibit relatively high efficiencies, reaching 30 percent or more. However, like second-generation cells, they are more likely to be manufactured using materials other than conventional silicon. These materials include amorphous silicon, organic polymers, perovskite crystals, and feature multiple junctions.