Oct 07, 2019 PERC solar cells Solar cell technology is always evolving and improving. PERC solar cells are a relatively new innovation in the solar industry – in this article, we’ll dive into what PERC solar cells are and how they impact solar panel technology. What are PERC solar cells? PERC can stand for either Passivated Emitter and Rear Cell or Passivated Emitter and Rear Contact. At its core, a PERC solar cell is simply a more efficient solar cell, meaning that solar panels built with PERC cells can convert sunlight into usable electricity more easily. Solar panels made from PERC solar cells typically perform better than traditional panels in both low-light conditions and high temperatures. PERC technology boosts efficiency through the addition of a layer to the back of a traditional solar cell, which provides several benefits to the cell’s production. One of the advantages of this technology is that moving to PERC manufacturing doesn’t require a lot of modifications to existing cell manufacturing processes. It’s a relatively easy shift for manufacturers to start producing higher efficiency PERC cells at a low cost. How are PERC solar cells different from standard solar cells? A PERC solar cell is not much different in construction from a typical photovoltaic solar cell. Both types of solar technology use silicon wafers to generate a flow of electrons using incoming solar radiation, and the overall construction of the cell types is very similar. The main difference between PERC cells and typical monocrystalline photovoltaic cells is the integration of a back surface passivation layer, which is a layer of material on the back of the cells that provides three main benefits that boost cell efficiency : 1. Reflection of light back through the cell A back surface passivation layer reflects light that passes through the silicon cell without being absorbed back into the silicon, giving the solar cell a second absorption attempt. This reflection of light means that more incoming solar radiation will end up being absorbed by the silicon cell, thus the cell generates more energy. 2. Reduced electron recombination The addition of a back surface passivation layer reduces “electron recombination” in the solar cell. Simply put, electron recombination is the tendency of electrons to recombine, which causes a blockage in the free movement of electrons through the solar cell. This inhibition of free electron movement leads to less-than-optimal cell efficiencies. In a PERC solar cell, electron recombination is reduced in order to bump up efficiency. 3. Reduced heat absorption The third benefit of a PERC solar cell is the reflection of certain wavelengths of light. A silicon wafer in a solar cell can only absorb light in wavelengths up to 1180 nanometers (nm), and higher wavelength light waves pass through the silicon and are absorbed by the solar panel’s metal back sheet, creating heat. When solar cells are heated, they operate at lower efficiencies. The back surface passivation layer in PERC solar cells is specially designed to reflect light with a wavelength above 1180 nm, reducing the heat energy in the solar cell and consequently increasing efficiency. PERC solar cell manufacturing One of the biggest reasons why PERC technology can be so powerful is the minimal investment it takes to begin manufacturing PERC solar cells instead of standard monocrystalline solar cells. In order to produce a PERC cell, there are two additional manufacturing steps needed: Application of the back surface passivation layer Laser/chemical etching to open small pockets in the passivation layer These two steps don’t add significant costs to the solar cell manufacturing process and result in a higher quality, more energy-dense solar cell. A classic barrier to new solar cell technology is the cost of new equipment production, and PERC solar cells require very little monetary investment to upgrade to a better product.