The Multi-crystalline silicon is also called as Poly-crystalline silicon and Polysilicon. Multi-crystalline silicon is solid silicon composed of many crystallites/grains of varying size and orientation. It is of high purity grade and used extensively in manufacture of polycrystalline solar panels and electronics. The efficiency of poly-crystalline-based solar panels is typically 13-16%. Because of lower silicon purity, poly-crystalline solar panels are not quite as efficient as mono-crystalline solar panels. Multi-crystalline panels need to cover a larger surface to output the same electrical power as you would with a solar panel made of mono-crystalline silicon.