There are three main types of solar panels. The key difference between them is the silicon wafers they are made with. The three main types are Polycrystalline (sometimes called multi crystalline), Mono Crystalline & Thin Film. We will discuss the differences between the three and also when it is better to use each type. There are also some other types of solar panels available but these are mainly for more specific purposes and are not so common.
Polycrystalline Solar Panels are made by melting many fragments of silicon together to form the wafers. Polycrystalline solar panels are generally less efficient than monocrystalline solar panels, but the are also cheaper to buy. This is due to the simpler manufacturing process. Both polycrystalline and monocrystalline solar panels reduce their efficiency the hotter they get. Poly crystalline solar panels are a good choice when being used in sunny climates or when budget is a key consideration. In sunny climates both monocrystalline and polycrystalline solar panels operate with around the same efficiency, so its more economical to use the cheaper polycrystalline panels.
Monocrystalline solar panels are made from a single cut of silicon. This makes them more efficient. This also mean that these solar panels are more expensive to buy. Monocrystalline solar panels are the most common panels used in the UK, this is because the also work better in lower light conditions. Like the polycrystalline solar panels they are also less efficient in sunny climates as they lose efficiency when they get hot. Some people still choose the monocrystalline panels for installations in sunny climates as the tend to work a little better on duller days.
Thin film solar panels )also known as amorphous solar panels) are the least efficient of the solar panels. With this inefficiency they are also the cheapest to manufacture. These are not so common however, and at times we don't benefit from the cheaper manufacturing cost. This is because they are not produced at the same scale as the poly and mono solar panels. One of the key benefits of the thin film solar panels is that they don't really lose their efficiency when they get hot. So for some applications these can be a good fit. For example a large solar array in the desert, where its rather hot and space is not a concern. It should however be noted that as more of these panels would be needed, there would also be additional costs in mounting hardware.
For more information on the types of solar panels you could read the post from Solar Reviews.