There are 3 types of photovoltaic (PV) panels. (These descriptions all relate to the type of solar panels that generate electricity – known photovoltaic panels.) The most common two are made up of cells of crystalline silicon. This type of PV panel needs to be mounted in a rigid frame to prevent any bending of the cells, as the cystalline silicon from which they are manufactured is quite brittle and breaks with very little flexing.
The most efficient kind are monocrystalline panels. So called because they use monocrystalline silicon as their base material. This type uses a single crystal of silicon. While they are the most expensive to produce, they are not considerably more expensive that the less efficient polycrystalline panels. Expected life of a monocrystalline panel is about 25 years.
Slightly less efficient that monocrystalline panels are the polycrystalline. They are also manufactured from crystalline silicon, but are made from slices of a conglomerate of crystals. They have a distinct speckled surface that looks somewhat like a piece of subtle mosaic art.
This type uses no crystalline at all. Instead, they use a substance called amorphous silicon. They are the cheapest to manufacture – and least efficient. They also have a “break in” period during their first few months of use, in which they lose some of their ability to generate power, whereas the crystalline types described above lose about the same amount of power, but very slowly over the entire life of the panels.