Table of Contents:
Key takeaways
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In simple terms, solar panels are made of protective layers mounted on a photovoltaic (PV) cell layer with adhesive layers and secured to a frame.
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PV cells are typically made from silicon crystals.
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There are several types of silicon crystal construction used in solar panels that vary in efficiency, application, and price.
Modern solar panels are made up of several layers, each with its own purpose. Combined, they create panels that can generate clean energy to power your home while standing up to decades of wind, weather, and debris—truly a marvel of modern engineering.
We created this guide to help you understand the different materials and components that are used in solar panel technology. You’ll also learn what choices you have when it comes to solar technology, and the distinct features of each one.
What are solar panels made of?
Home solar panels are made of several key materials that work together to convert sunlight into electricity. A solar panel contains silicon cells, which act as the main semiconductors. These cells are protected by a layer of tempered glass. Metal frames, usually aluminum, hold everything together. Wires connect the cells, while a plastic or polymer backing insulates and protects the panel.
Here’s a detailed overview of the different solar panel components:
| Component | Definition | Main purpose |
|---|---|---|
| Silicon Wafers | Thin slices of crystalline silicon that convert sunlight into electricity | Core PV material |
| Glass Layer | Tempered glass that protects the panel and lets light pass through | Structural protection |
| EVA (Encapsulant) | Transparent material that bonds and protects solar cells from moisture and UV | Encapsulation material |
| Backsheet | Rear layer that protects internal components and insulates electrically | Structural layer |
| Frame | Aluminum border that provides structural support and allows for mounting | Mechanical support |
| Solder and Busbars | Conductive materials connecting cells for electric current flow | Electrical conduction |
| Anti-Reflective Coating | Reduces light reflection to increase absorption | Efficiency enhancer |
| Junction Box | Housing for wiring and bypass diodes, located on the back of the panel | Electrical interface |
| Photovoltaic Cell | The active part of the panel that converts light into electricity | Energy generation component |
| TPT Backsheet | Common composite backsheet made for durability and weather resistance | Backsheet material |
| Adhesive Sealant | Bonds panel layers and seals against water and air intrusion | Assembly component |
| PERC Layer | Backside layer that improves electron reflection and cell efficiency | Cell design innovation |
Next, we’ll cover a few main components in detail.
Photovoltaic (PV) cell layer
The component of solar panels that is the site of the reaction that generates electricity is the PV cell layer. Photovoltaic cells have materials—usually silicon—that serve as their primary conductor, capturing sunlight and converting it to electricity through the photovoltaic effect.
While pure silicon can conduct electricity, it is not ideal for creating a strong electric field. To enhance its performance, manufacturers dope the silicon with trace amounts of other elements. One layer is doped with boron to create a p-type semiconductor with an excess of "holes" (positive charge carriers), and the other layer is doped with phosphorus to create an n-type semiconductor with extra electrons. When sunlight excites the electrons, they move across the p-n junction, generating an electric current.
Protective layers
Solar panels use protective layers on either side of the PV cell layer to shield it from the environment:
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Tempered glass (top layer): The side of the solar panel that faces the sun is covered with a layer of strong tempered glass that is resistant to scuffs and cracks while still allowing light to easily pass through to the PV layer.
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Ethyl vinyl acetate (EVA) encapsulant: Solar panels use a thin adhesive film made of EVA that sticks the PV layer to the other layers. This film also has the benefit of being UV-resistant, helping extend the lifetime of the PV layer.
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Backsheet: Most solar panels are monofacial panels, meaning they only capture light from the top side. On these panels, the backsheet that sits between the PV layer and the frame is opaque and typically metal. On bifacial panels that capture light from behind the panel, the backsheet is transparent—often the same tempered glass used on the top layer.
Frame and mounting hardware
The layered solar panel assembly sits on a metal—usually aluminum—frame that positions them at an angle facing the sun and secures them to the roof or other surface. As a system, this equipment is known as solar racking.
Junction box
Solar panel setups employ a plastic junction box that protects the electrical components from water, dirt, and other elemental hazards.
Types of solar cells and their differences
There are several different types of solar panels that employ varying types of solar cells. Each type has distinct features and its own advantages and disadvantages to consider.
Monocrystalline silicon solar cells
Monocrystalline cells are made from a single piece of silicon, which makes them more efficient at generating electricity and more durable than other types of solar cells. They are the most expensive type of PV cells. However, despite their high cost, they are the most popular type of solar cells used in residential solar panels in the U.S.
Polycrystalline silicon solar cells
Polycrystalline cells are made by fusing several smaller pieces of silicon together to create the PV layer. These are less efficient and don’t typically last as long as monocrystalline cells. However, they are significantly cheaper than monocrystalline cells, as well as more sustainable to produce.
Amorphous silicon solar cells
Also called thin-film solar technology, amorphous silicon (a-Si) solar cells are made by pressing a non-crystalline form of silicon onto a surface—typically made of glass, metal, or plastic. Compared to crystalline solar cells, amorphous silicon cells are more lightweight and more flexible, but less efficient. That makes them a popular choice for portable solar applications or small-scale use.
How solar panels work step by step
Don’t let the scientific terms scare you away—the PV effect that creates energy in solar panels is remarkably simple. We’ve outlined the steps in the PV process below to help you get a better understanding of how it works.
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Sunlight passes through the tempered glass and EVA layers and reaches the PV cell layer.
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As the silicon solar cell absorbs photons from the sunlight, it excites electrons within the doped silicon layers.
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The p-type layer (doped with boron) and the n-type layer (doped with phosphorus) form an electric field at the p-n junction, which drives the excited electrons toward the n-type side, creating direct current (DC) electricity.
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Electrical contacts, known as metal fingers, collect the electrons and direct them to conductive strips called busbars.
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The busbars transmit the DC electricity from the panel to a solar inverter.
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Housed in a protected junction box, the inverter converts the DC electricity into alternating current (AC) that can power your home.
Bottom line on solar panel construction
The layers that make up solar panel assemblies allow them to do their job of generating electricity through the PV effect while staying safe and secure in their location. Like most consumer goods, you have a range of choices when it comes to the type of solar panel you buy, the materials used to produce it, and the price you pay. You can use the information from this article to help you make a more informed decision about the equipment you go with for your solar energy system.
If you analyze the cost and decide solar isn’t worth it, that’s OK, too. Not all homes, energy markets, or climates are the best for solar panels.
FAQ about what solar panels are made of
Below are a few frequently asked questions about solar panel construction:
What materials are solar panels made of?
The materials used to make solar panels include silicon crystals for the photovoltaic (PV) cells, tempered glass for one or more protective layers, ethyl vinyl acetate (EVA) film for an adhesive layer, metal or plastic for the backsheet, and aluminum for the frame.
What metal is used in solar panels?
The metal used in solar panel frames is usually aluminum. Aluminum works well for its favorable ratio of weight to strength and durability.
Is there anything bad about solar panels?
One point of concern about solar panels is the sustainability issues with the silicon crystals used to make PV cells. There are questions about whether the mining of silicon and the manufacture of PV cells are sustainable as solar panels become more commonplace.
Where does silicon for solar panels come from?
The most popular source of silicon ore for solar panels is sand, but it is also mined from quartz, mica, and talc. China mines and refines an overwhelming majority of the silicon used in solar panels.