Solar has entered the mainstream as the world’s cheapest energy source, leaving many people wondering how solar PV can be so efficient and inexpensive while still providing “green” energy. Answering that question means understanding how solar panels work and what exactly they’re made of. Most solar panels available on the market are made of monocrystalline, polycrystalline, or thin film (“amorphous”) silicon. In this article, we’ll explain the different ways solar cells are made and what materials are required to manufacturer a solar panel.
Mono vs. poly vs. thin film: how different solar cells are made
Solar photovoltaics are made with a number of components, the most important of which are silicon cells. Silicon, atomic number 14 on the periodic table, is a nonmetal with conductive properties that give it the ability to convert sunlight into electricity. When light interacts with a silicon cell, it causes electrons to be set into motion, which initiates a flow of electricity. This is known as the “photovoltaic effect.”
However, silicon cells alone can’t provide electricity for your home. They are paired with a metal casing and wiring, which allow the solar cell’s electrons to escape and supply useful power. Silicon comes in a number of different cell structures: single cell (mono-crystalline), polycrystalline or amorphous forms, most commonly associated with thin film solar panels.
Mono-crystalline solar panels are produced from one large silicon block and are produced in silicon wafer formats. The manufacturing process involves cutting individual wafers of silicon that can be affixed onto a solar panel. Mono-crystalline silicon cells are more efficient than polycrystalline or amorphous solar cells. However, producing individual monocrystalline wafers is more labor-intensive, and consequently, they are also more expensive to manufacture than polycrystalline cells. Mono cells have a distinct black aesthetic and are often associated with the sleek look of SunPower’s premium panels.
Polycrystalline solar cells are also silicon cells, but rather than being formed in a large block and cut into wafers, they are produced by melting multiple silicon crystals together. Many silicon molecules are melted and then re-fused together into the panel itself. Polycrystalline cells are less efficient than monocrystalline cells, but they are also less expensive. They have a blueish hue that is often associated with the aesthetic of SolarWorld solar panels.
Finally, amorphous silicon cells create flexible panel materials that are often used in thin film solar panels. Amorphous silicon cells are non-crystalline and instead are attached to a substrate like glass, plastic or metal. For this reason, thin film solar panels are true to their name: they are lean and bendable, unlike a standard panel. Though an ideal use case for versatility, amorphous solar cells are very inefficient compared to mono or polycrystalline cells. First Solar is best known for manufacturing thin film panels in the U.S.
List of solar panel materials
The materials used to manufacture the cells for solar panels are only one part of the solar panel itself. The solar panel manufacturing process brings together six different components. If you are DIY-minded and curious about solar panel materials, it may even be a question of wanting a hypothetical “ingredients” list to produce one on your own. Here are the common materials required for a standard PV panel:
- Silicon solar cells
- Metal frame (typically aluminum)
- Glass sheet for casing
- Standard 12V Wire
- Bus wire
In addition to the solar cells themselves, a standard solar panel includes a glass casing at the front of the panel to add durability and protection for the silicon PV. Under the glass exterior, the panel has a casing for insulation and a protective back sheet, which helps to limit heat dissipation and humidity inside the panel. The insulation is particularly important because temperature increases will lead to a decrease in efficiency, resulting in a lower solar panel output. Thus, PV manufacturers must go extra lengths to ensure that light is being captured without the technology being overheated.
Should you make your own solar panels?
For anyone wanting to install solar who is considering a do-it-yourself route, there are a number of factors to consider such as warranties, longevity of output, efficiency and overall cost. To get a full sense of this breakdown, check out our article on the pros and cons of DIY solar. If you’re looking for a personalized estimate for what a solar installation would cost based on your specific location and roof type, try our Solar Calculator. For homeowners interested in receiving quotes from local, pre-screened installers, check out the EnergySage Solar Marketplace.