Polycrystalline Solar Panels:
By the name, the polycrystalline are also called multi-crystalline. A polycrystalline panel is also called poly panel or simply blue panel. The poly panels are made of square silicon wafers. Their manufacturing process is simpler and cheaper with less silicon waste. Their manufacturing temperature is less than that of monocrystalline panels, and these effective in high operating temperatures. However, ploy panels are less efficient due to low silicon impurity thus need a larger footprint to achieve required energy demand.
Monocrystalline Solar Panels:
By the name, the monocrystalline are also called single-crystalline. A monocrystalline panel is also called mono panel or simply black panel. These are not actually black panels but are dark blue. The cells are made of cylindrical ingot instead of square blocks (as used for poly panels), cut into wafers and pass through several washing and cleaning processes to achieve high silicon impurity. Their manufacturing temperature is higher than poly panels, but these are less effective at higher operating temperatures. However, these do perform well at low irradiation and require smaller footprint than poly panels. Therefore, a smaller size mono panel could have higher watts compared to a poly panel of same size. Mono panels are slightly expensive than poly panels due to the higher manufacturing costs but are worth installing in low to moderate temperature areas.
Figure: Illustration image of various type of panels (courtesy diysolarhack.com)
Thin Film Solar Panels:
These are commonly known as amorphous silicon panels made in a similar way that newspapers are printed. The positive (cathode) and anode (negative) are formed by spraying the semiconductor material on both side of the think aluminium film. These panels are flexible and can be rolled themselves. The most common usage of these type of panels is outdoor campers and marine etc. Being delicate, these are less efficient (7-13%) and susceptible to high temperatures. These are light weight as easy to carry.
Flexible Solar Panels:
These are technically a type of mono panels that means cells are cut in further thinner slices from an ingot of semiconductor. These are also commonly used for outdoor activities. Their efficiency is like thin film panels (13%). These are light weight as easy to carry.
This topic is technical and sometimes difficult to understand, but we tried keeping the information simple for your understanding.
We hope this information would allow you to decide, depending upon your requirements and likeliness, which type of panels you would be looking to buy.