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 have better efficiency and power capacity.