The key part of any solar panels are solar cells. They are made of photovoltaic material, which allows them to produce current under the sun. Almost all solar cells are made of silicon, a component of beach sand. First, silica sand is exposed to high temperatures in the furnace. Once you have a pot of melted silicone, the process starts to differ for monocrystalline and polycrystalline panels.
To make polycrystalline solar cells, hot silicon is poured into a square mould. As it cools down, it forms many rocks or so called crystals. Then this silicone ingot gets sliced into thin wafers. They are of a perfect square shape: when they are laid up into a panel, there is no wasted space.
The process of making monocrystalline solar cells is more complicated. First, manufacturers grow a single large crystal from melted silicone. This process is called Czochralski and reminds of making cotton candy. In the end, they get a big silicon cylinder. If it were sliced as it is, wafers would be round discs, which couldn't be efficiently packed into a solar panel. There would be gaps between the cells, leaving parts of the solar panel surface inactive. So the cylinder is first cut along its length on four sides to get wafers of a square shape with rounded corners (pseudo-square). The remnants of the manufacturing process are later used for making polycrystalline cells.
The wafers, both poly- and monocrystalline, are usually polished to remove saw marks. However, it increases their reflectivity up to around 40%, which means a lot of sunlight is wasted. Anti-reflective coating used for polycrystalline panels lowers it down to 6% and gives solar modules their distinctive blue hue. A special modern technology
is used to make "black silicone", the standard for monocrystalline panels. Their reflectivity goes even further down to 1.5%.
Solar cells are the most important, but aren't the only component of PV modules. If you want to know more about the manufacturing process of solar panels and how they work, check out our article
Now let's look at each type of solar panels closer to figure out which situations they suit the best.