Types of solar panels: What you need to know

Three types of solar panels are primarily available today: monocrystalline, polycrystalline (also known as multi-crystalline), and thin film. These solar panels vary in appearance, performance, costs, and how they're made. Depending on the photovoltaic (PV) installation you're considering, one option may be more suitable than the others. In this article, we break down each type of solar panel by cost, materials, appearance, and efficiency to help you understand which is best.

There are three major types of solar panels: monocrystalline, polycrystalline, and thin-film. Each type has its own unique advantages and disadvantages – the solar panel type best suited for your installation will depend on your preferences and factors specific to your own property.

Major types of solar panels

Below, we'll break down some common questions and concerns about solar panels and how different types of panels have varying characteristics.

The manufacturing processes differ between monocrystalline, polycrystalline, and thin-film; as a result, each type of panel comes with a different price tag.

Monocrystalline solar panels: The most expensive

Monocrystalline panels are likely to be the most expensive option of all the solar panel types. This is mainly due to the manufacturing process – manufacturers must absorb the costs of making solar cells from a single crystal. This process, known as the Czochralski process, is energy-intensive and results in wasted silicon (that can later be used to manufacture polycrystalline solar cells).

Polycrystalline solar panels: Middle of the road

Polycrystalline solar panels are typically cheaper than monocrystalline solar panels. The cells are produced from silicon fragments rather than a single, pure silicon crystal. This allows for a much simpler cell manufacturing process, thus costing less for manufacturers and, eventually, end-users.

Thin-film solar panels: It depends!

What you pay for thin-film solar cells will largely depend on the type of thin-film panel; CdTe is generally the cheapest type of solar panel to manufacture, while CIGS solar panels are much more expensive to produce than CdTe or amorphous silicon.

Regardless of the panels' cost, the overall cost of a thin-film solar panel installation may be lower than installing a monocrystalline or polycrystalline solar panel system due to additional labor requirements. Thin-film solar panel installations are less labor-intensive because they're lighter and more maneuverable, making it easier for installers to carry panels onto rooftops and secure them. This means reduced labor costs, which can help contribute to an overall less expensive solar installation.

To produce electricity, solar PV cells are made from a semiconducting material that converts light into electricity. The most common material used as a semiconductor during the solar cell manufacturing process is silicon.

What are crystalline solar panels made out of?

Both monocrystalline and polycrystalline solar panels have cells made of silicon wafers. To build a monocrystalline or polycrystalline panel, wafers are assembled into rows and columns to form a rectangle, covered with a glass sheet, and framed together.

While both of these types of solar panels have cells made from silicon, monocrystalline and polycrystalline panels vary in the composition of the silicon itself. Monocrystalline solar cells are cut from a single crystal of silicon. Alternatively, polycrystalline solar cells are composed of fragments of silicon crystals that are melted together in a mold before being transformed into ingots and cut into wafers.

What are thin-film solar panels made out of?

Unlike monocrystalline and polycrystalline solar panels, thin-film panels are made from various materials. The most prevalent type of thin-film solar panel is made from cadmium telluride (CdTe). To make this type of thin-film panel, manufacturers place a layer of CdTe between transparent conducting layers that help capture sunlight. This type of thin-film technology also has a glass layer on the top for protection.

Thin-film solar panels can also be made from amorphous silicon (a-Si), which is similar to the composition of monocrystalline and polycrystalline panels. Though these thin-film panels use silicon layers in their composition, they are not made up of solid silicon wafers. Instead, they're composed of non-crystalline silicon placed on top of glass, plastic, or metal.

Lastly, Copper Indium Gallium Selenide (CIGS) panels are another popular type of thin-film technology. CIGS panels have all four elements between two conductive layers (i.e., glass, plastic, aluminum, or steel). Electrodes are placed on the material's front and back to capture electrical currents.

The differences in materials and production cause differences in appearance between each type of solar panel:

Monocrystalline solar panels: Black

If you see a solar panel with black cells, it's most likely a monocrystalline panel. These cells appear black because light interacts with the pure silicon crystal.

While the solar cells are black, monocrystalline solar panels have a variety of colors for their back sheets and frames. The back sheet of the solar panel will most often be black, silver, or white, while the metal frames are typically black or silver.

Polycrystalline solar panels: Blue

Unlike monocrystalline solar cells, polycrystalline solar cells tend to have a bluish hue due to the light reflecting off the silicon fragments in the cell in a different way than it reflects off a pure monocrystalline silicon wafer.

Like monocrystalline, polycrystalline panels have different colors for back sheets and frames. Most often, the frames of polycrystalline panels are silver, and the back sheets are either silver or white.

Thin-film solar panels: Low-profile

The most significant differentiating aesthetic factor in thin-film solar panels is how thin and low-profile the technology is. As their name suggests, thin-film panels are often slimmer than other panel types. This is because the cells within the panels are roughly 350 times thinner than the crystalline wafers used in monocrystalline and polycrystalline solar panels.

It's important to remember that while the thin-film cells themselves may be much thinner than traditional solar cells, an entire thin-film panel may be similar in thickness to a monocrystalline or polycrystalline solar panel if it includes a thick frame. There are adhesive thin-film solar panels that lie as-close-as-possible to the surface of a roof, but there are more durable thin-film panels with frames up to 50 millimeters thick.

As far as color goes, thin-film solar panels can come in both blue and black hues, depending on what they're made from.

Each type of solar panel varies in the amount of power it can produce. We break down the energy efficiency of each type of solar cell below:

Crystalline solar panels

Of all panel types, monocrystalline panels typically have higher efficiency and power capacity. Monocrystalline solar panels can reach efficiencies of over 20%, while polycrystalline solar panels' efficiency is usually between 15 to 17%.

Monocrystalline solar panels tend to generate more power than other types of modules not only because of their efficiency but because they often have higher capacity as well. Most monocrystalline solar panels provide over 300 watts (W) of power capacity, some even exceeding 400 W. Polycrystalline solar panels, on the other hand, tend to have lower wattages. Monocrystalline solar panels also tend to outperform polycrystalline models regarding temperature coefficient – a measure of a panel's performance in warm temperatures. Essentially, this means that monocrystalline panels typically perform better in high temperatures.

This doesn't mean that monocrystalline and polycrystalline solar panels aren't physically the same size. Both types of solar panels tend to come in 60, 72, and 96 silicon cell variants. But even with the same number of cells, monocrystalline panels can produce more electricity.

Thin-film solar panels

Thin-film solar panels have lower efficiencies and power capacities than monocrystalline or polycrystalline varieties. Efficiencies will vary based on the specific material used in the cells, but thin-film solar panels tend to be around 11% efficiency.

Unlike monocrystalline and polycrystalline solar panels that come in standardized 60, 72, and 96-cell variants, thin-film technology does not come in uniform sizes. As such, the power capacity from one thin-film panel to another will largely depend on its physical size. Generally, the power capacity per square foot of monocrystalline or polycrystalline solar panels will exceed the technology of thin-film panels.

As you choose the type of solar panel you'd like for your system, much of your decision will come down to the specifics of your property and situation. Monocrystalline, polycrystalline, and thin-film panels each have advantages and disadvantages, and the solution you should move forward with depends on your property and your goals for the solar project.

Homeowners with a lot of space for solar panels can save money upfront by installing lower-efficiency, lower-cost polycrystalline panels. If you have limited space available and want to maximize your electric bill savings, you can install high-efficiency, monocrystalline solar panels.

As far as thin-film panels go, it's most common to choose this type of solar panel if you're installing a large, commercial roof that can't handle the additional weight of traditional solar equipment. These roofs can also afford the lower efficiencies of thin-film panels because they have more roof space to place them on. Additionally, thin-film panels can sometimes be useful for portable solar systems, like on RVs or boats.

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