While new technologies are in development, there are three types of solar panels widely used on the market today.
- Polycrystalline (a.k.a. multi-crystalline)
These solar panels differ in appearance, performance, costs, use and prosses of installation. Each has its advantages and disadvantages, but which one is best depends on the solar power system application.
Monocrystalline & Polycrystalline Panels
Solar cells turn light into electricity by using a semiconductor, the most common material used for this is silicon.
Monocrystalline and Polycrystalline solar panels have solar cells made of silicon wafers, but the composition of the silicon varies in each panel. Monocrystalline cells are cut from a single crystal of silicon, this is known as Mono Silicon. Polycrystalline solar cells are composed of silicon crystal fragments melted together and then cut into wafers, this is known as Poly Silicon. Both types are then covered in a protective glass and mounted in an aluminum frame.
Despite their difference in silicon technology, monocrystalline and polycrystalline solar panels are relatively the same size. Both are commonly comprised of 60 silicon cells, with 72 and 96 cell variants for large-scale projects. However, monocrystalline panels are capable of producing more electricity.
Monocrystalline solar panels have black solar cells, they appear black because of how the light interacts with the pure silicon crystal. While the solar cells themselves are black, the back of a monocrystalline solar panel is most often black, silver or white, and the metal frame is typically black or silver.
Monocrystalline panels are between 15-20% efficient or even higher, and cost more.
Polycrystalline solar cells have a bluish tint because light reflects off the silicon fragments in a different way than it reflects off a pure monocrystalline silicon wafer. The back of the frame on a polycrystalline panel is most often silver or white, and the frame is usually silver.
Polycrystalline panels are known to be between 15-17% efficient, and cost less.
Thin-film solar panels
There are three mainstream thin-film photovoltaic (PV) technologies
- Cadmium Telluride (CdTe)
- Amorphous silicon (a-Si)
- Copper Indium Gallium Selenide (CIGS)
Cadmium Telluride (CdTe) For this type of thin-film panel a layer of CdTe is placed between transparent conducting layers that capture sunlight. A thin layer of glass is then placed on top for protection.
Amorphous silicon (a-Si) These thin-film panels are similar in makeup of the crystalline panels as they use silicon in their construction, but they’re not made up of solid silicon wafers. They’re composed of non-crystalline silicon placed on top of glass, plastic, or metal.
Copper Indium Gallium Selenide (CIGS) CIGS solar cells are made of a thin layer of Copper Indium selenide, Copper Gallium Selenide and a trace amount of Sodium. The thin-film cell is then deposited onto a substrate, such as soda-lime-silica glass, metal, or a polyamide film, to form a contact surface. Electrodes are then placed on the front and the back of the material to capture electrical current.
The biggest visual factor with thin-film solar panels is how thin and low-profile they are. As the name implies, thin-film panels are slimmer and thinner than crystalline panels.
While thin-film cells may be much thinner than silicon based solar cells, the panel itself can be similar in thickness to that of a crystalline panel if it includes a thick frame, however, some thin-film solar panels are made to lie flat, or close to flat, on the surface of a roof, but more durable thin-film panels have thicker frames.
Thin-film solar panels can be black or blue in color depending on what material they’re made of and unlike crystalline solar panels that come in 60, 72 and 96 cell variants, thin-film panels do not come in uniform sizes. Therefore, the power capacity of any given thin-film panel will depend on its actual size. Overall, the power capacity per square foot of crystalline solar panel will exceed thin-film panel technology.
Due to weight and maneuverability, thin-film panels are less labor-intensive to install. This means reduced labor costs, which can help contribute to an overall less expensive solar installation.
Thin-film panels vary in efficiency based on which material is used in the cells. On average a Thin-Film panel is around 11% efficient.
Which solar panel is best for me?
Each panel has its advantages and disadvantages. Which one to use is largely determined by the end goal of your solar project. Your property and unique situation may play a part in this decision as well. If you have plenty of space for solar panels, you can cut cost by installing polycrystalline panels, they’re less efficient than monocrystalline but also cost less. If you’re limited on space for panel installation and aim to maximize savings on your electric bill, monocrystalline panels may be a better choice.
While thin-film panels are a great solution for portable solar systems, generators, RVs, campers and boats, they’re also a common choice for large commercial roof installations when weight may be a concern. In addition, large roof projects can often afford the lower efficiency thin-film panels because they have enough area to place more panels, allowing business to cut cost upfront in materials and labor.
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