Polycrystalline Solar Panels are the most common because they are often the least expensive. They are the middle choice in the marketplace … almost as good as single cell monocrystalline silicon panels but generally with a better efficiency than thin film solar panels.
Polycrystalline cells can be recognized by a visible grain, a “metal flake effect”. The solar cells are generally square in shape, and may have a surface that looks somewhat like a mosaic. That’s because of all the different crystals that make up the module.