Solar panel is a component of a photovoltaic system that is made out of a series of photovoltaic cells arranged to generate electricity using sunlight.

The 4 Main Types of Solar Panels

1) Monocrystalline,

2) Polycrystalline,

3) PERC

4) Thin-film panels.

Monocrystalline solar panels

Also known as single-crystal panels, these are made from a single pure silicon crystal that is cut into several wafers. Since they are made from pure silicon, they can be readily identified by their dark black color. The use of pure silicon also makes monocrystalline panels the most space-efficient and longest-lasting among all three solar panel types. However, this comes at a cost — a lot of silicon is wasted to produce one monocrystalline cell, sometimes reaching over 50%. This results in a hefty price tag.

Polycrystalline solar panels

As the name implies, these come from different silicon crystals instead of one. The silicon fragments are melted and poured into a square mold. This makes polycrystalline cells much more affordable since there is hardly any wastage, and gives them that characteristic square shape. However, this also makes them less efficient in terms of energy conversion and space, since their silicon purity and construction are lower than monocrystalline panels. They also have lower heat tolerance, which means they are less efficient in high-temperature environments.

Passivated Emitter and Rear Cell (PERC) panels

PERC solar panels are an improvement of the traditional monocrystalline cell. This relatively new technology adds a passivation layer in the rear surface of the cell that enhances efficiency in several ways:

• It reflects light back into the cell, increasing the amount of solar radiation that gets absorbed.
• It reduces the natural tendency of electrons to recombine and inhibit the flow of electrons in the system.
• It allows greater wavelengths of light to be reflected. Light waves over 1,180nm can’t be absorbed by silicon wafers and simply pass through, so they end up heating the cell’s metal back sheet and reduce its efficiency. The passivation layer reflects these higher wavelengths and stops them from heating up the back sheet.

Thin-film solar panels

Thin-film panels are characterized by very fine layers that are thin enough to be flexible. Each panel does not require a frame backing, making them lighter and easier to install. Unlike crystalline silicon panels that come in standardized sizes of 60, 72, and 96-cell counts, thin-film panels can come in different sizes to suit specific needs. However, they are less efficient than typical silicon solar panels.

Solar Panel Types by Efficiency

Among all panel types, crystalline solar panels have the highest efficiency.

• Monocrystalline panels have an efficiency rating over 20%.
• PERC panels add an extra 5% efficiency thanks to their passivation layer. 
• Polycrystalline panels hover somewhere between 15-17%.

In contrast, thin-film panels are usually 2-3% less efficient than crystalline silicon. On average:

• CIGS panels have an efficiency range of 13-15%.
• CdTe ranges between 9-11%.
• a-Si have the lowest efficiency at 6-8%.