There are many different types of solar cells, which are the small, light harnessing devices that convert the sun’s rays into usable electricity. Solar panels are in fact sheets composed of large arrangements of different types of solar cells.
The most common material used among the different types of solar cells is a substance known as crystalline silicon. In the context of solar energy, this material is often referred to as “solar grade silicon.” Silicon-based solar cells can be further divided into three separate categories.
Monocrystalline or single-crystal silicon is among the most common of the different types of solar cells. These cells are manufactured through a detailed process of purifying, melting, and crystallizing the silicon into solid ingots, or bars. With the purified silicon crystallized, it is cut into thin discs which are laid out over the surface of a solar panel. Like other types of silicon solar cells, the cells are activated when photons strike the surface of the cell. Photons are the small particles of energy which constitute sunlight. Photons striking the solar cells causes a disruption and directional flow of electrons, a phenomenon which constitutes electrical current, and in this case, the basis of solar power.
Polycrystalline or multicrystalline silicon cells are another type of solar cell which make solar energy possible. These cells are manufactured in a process similar to that of monocrystalline silicon cells. However, multicrystalline silicon cells utilize lower cost silicon, resulting in diminished efficiency. Despite this drawback, the reduced cost of these types of solar cells may outweigh the resulting loss of harnessing solar energy.
A third type of of silicon solar cells is known as ribbon silicon. Rather than crystallizing the silicon into a solid bar, these solar cells are made by drawing molten silicon into a long ribbon and eliminates the processing of cutting silicon into discs. Although ribbon silicon is less efficient than polycrystalline solar cells, costs are greatly reduced, as the silicon used is a lower grade. Furthermore, since this process does not involve cutting of the material, there is little to no waste of silicon, further reducing production costs.
In contrast to crystalline silicon solar cells, thin film solar cells are assembled with several layers of different types of solar power-producing materials. This type of solar cell is also referred to as “amorphous silicon,” as it lacks the crystal-like structure present in crystalline silicon solar cells. There are several different types of thin film solar cell materials, including amorphous silicon, cadmium telluride, copper indium gallium selenide, and dye-sensitized solar cells.
This variation of solar cells allows portions of light to pass through the first layer, where it can be absorbed in subsequent layers. Because sunlight exists in different wavelengths, the different layers of a thin film solar cell can be adjusted to absorb different wavelengths of light and convert them in to solar energy. Thin film solar cells are much less efficient than other types, but are also much less expensive. A great deal of research is being dedicated to improving the efficiency of thin film solar cells. Of all the different types of solar cells, these have tremendous promise as a large-scale, cost effective solar power option.