Both Monocrystalline and Polycrystalline Solar PV Panels are made from Silicon
The main difference between the two technologies is the type of silicon solar cell they use: monocrystalline solar panels have solar cells made from a single crystal of silicon, while polycrystalline solar panels have solar cells made from silicon fragments melted together.
Monocrystalline solar panels
The main advantages of monocrystalline solar panels are higher efficiencies.
Silicon is formed into bars and cut into wafers to manufacture the cells for monocrystalline solar panels. These panels are called “monocrystalline” to indicate that the silicon used is single-crystal silicon. Because cells are made of a single crystal, the electrons have more room to move to generate a flow of electricity. Therefore, monocrystalline PV panels are more efficient than polycrystalline PV panels.
Polycrystalline solar panels
Polycrystalline solar panels have lower efficiencies than monocrystalline panels but cost less. Polycrystalline solar panels tend to have a blue hue instead of the black hue of monocrystalline panels.
For polycrystalline solar panels, instead of using a single crystal of silicon, many fragments of silicon are melt together to form the wafers for the panel. Because there are many crystals in each cell, there is less freedom for the electrons to move. Therefore, polycrystalline solar panels have a lower efficiency than monocrystalline panels.
What other solar cell technologies are there?
There are other solar panel options available besides mono and polycrystalline PV panels, but they make up a small percentage of the solar panel market. One technology is thin-film solar, which includes panels made from a variety of materials that are more lightweight and flexible than typical silicon panels. However, they lag behind crystalline silicon technology in terms of efficiency and performance.
New solar cell technologies are being developed that could challenge both monocrystalline and polycrystalline solar panels in the near future. It is likely that within a few years there will be new cell types available that will use multiple different cell technologies within one cell to generate significantly improved efficiencies.
Panasonic PV panels use HIT cell technology – these solar cells are predominantly monocrystalline but also have layers of amorphous silicon to increase efficiency and improve performance at high temperatures.
The Key Facts about Each Type of Solar Cell
Monocrystalline Solar PV Panels
This is the oldest and most developed of the three technologies. Monocrystalline panels, as the name suggests, are created from a single continuous crystal structure. A monocrystalline panel can be identified by the solar cells, which all appear as a single, flat colour.
Monocrystalline solar PV panels are made through the Czochralski method, where a silicon crystal ‘seed’ is placed in a vat of molten silicon. The seed is then slowly drawn up with the molten silicon forming a solid crystal structure around the seed, called an ‘ingot’. The ingot of solid crystal silicon that is formed is then finely sliced into what is known as a silicon wafer. This is then made into a cell.
The Czochralski process results in large cylindrical ingots. Four sides are cut out of the ingots to make silicon wafers. A significant amount of the original silicon ends up as waste.
Polycrystalline Solar PV Panels
Polycrystalline (or multicrystalline), is a newer technology and its manufacturing process varies.
Polycrystalline panels also start as a silicon crystal ‘seed’ placed in a vat of molten silicon. However, rather than drawing the silicon crystal seed up as with monocrystalline, the vat of silicon is allowed to cool. The cooling forms the distinctive edges and grains within the solar cell.
Polycrystalline cells were thought to be inferior to monocrystalline cells because they were slightly less efficient. However, because of the cheaper method by which they are produced and only slightly lower efficiencies, they take up a significant market share in residential installations.
Polycrystalline cells, with continued quality improvements, are now very close to monocrystalline solar cell efficiencies.
Solar PV Panels Lifespan
Because both types of crystalline solar panels are made from crystalline silicon, a stable material, it is very likely that these solar panels will last much longer than their 25-year warranty life.