Solar modules are made up of individual solar cells, each of which is made up of layers of silicon, boron and phosphorus. The boron layer provides a positive charge, the phosphorus layer provides a negative charge, and the silicon wafer acts as a semiconductor.
When the sun’s photons hit the surface of the panel, they knock out electrons from the silicon “sandwich” and enter the electric field generated by the solar cell. This creates a directional current that is converted into available power. Solar panels are also known as photovoltaic modules or PV modules because the entire process is called the photovoltaic effect.
The 3 major types of solar panels available on the market today are monocrystalline, polycrystalline and PERC solar panels.
Monocrystalline : They consist of a single pure silicon crystal sliced into several wafers. Made of pure silicone, it is dark black and easy to identify. The use of pure silicon also makes monocrystalline panels the most space-saving and durable of the three most common solar panel types.
Polycrystalline : They come from different silicon crystals instead of one. The silicon fragments are melted and poured into a square mold. Because it does not produce any wastage, this makes polycrystalline cells significantly cheaper. However, the purity and structure of silicon is lower than that of monocrystalline panels, whish also reduces efficiency in terms of energy conversion and space requirements. In addition, its low heat resistance reduces efficiency in high temperatures environments.
PERC solar panels : They are an improvement of the traditional monocrystalline cell. This relatively new technique adds a passivation layer to the back of the cell and improves 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 obstruct the flow of electrons in the system.
- It allows it to reflect light of longer wavelengths.