There are three major types of solar PV modules.
- Poly-crystalline (also known as multi-crystalline)
Each solar PV module type has its own unique features. These PV modules also vary based on how they’re manufactured, their appearance, performance, costs each are best suited for.
Mono-crystalline and Poly-crystalline solar PV modules
Both mono-crystalline and poly-crystalline solar PV modules have cells made of silicon wafers. To build a mono-crystalline or poly-crystalline module, wafers are assembled into rows and columns covered with a glass sheet, and framed together. Poly-crystalline cells are square-shaped whereas mono-crystalline cells are square with missing corners.
While both of these types of solar PV modules have cells made from silicon, mono-crystalline and poly-crystalline modules vary in the composition of the silicon itself. Mono-crystalline solar cells are cut from a single, pure crystal of silicon. Alternatively, poly-crystalline solar cells are composed of fragments of silicon crystals that are melted together in a mold before being cut into wafers. Mono-crystalline modules typically have the highest efficiencies and power capacity.
Thin-film solar PV modules
Unlike mono-crystalline and poly-crystalline solar PV modules, thin-film modules are made from a variety of materials. The most prevalent type of thin-film solar module is made from cadmium telluride (CdTe).
To make this type of thin-film module, manufacturers place a layer of CdTe between transparent conducting layers that help capture sunlight. This type of thin-film technology also has a glass layer on the top for protection.
Other materials used to manufacture a thin-film PV module are amorphous silicon (a-Si) and Copper Indium Gallium Selenide (CIGS). Thin-film solar modules are thin and often slimmer than other solar PV module types. Thin-film solar modules also tend to have lower efficiencies and power capacities than mono-crystalline or poly-crystalline modules.