What Are Solar Panels Made of?
You might know what solar panels can do – convert sunlight into energy, save money, create energy independence, increase your home’s resale value – but how do they do it? What are solar panels made of?
Silicon: Number 14 on the Periodic Table, Number 1 in Solar Panels
After oxygen, silicon is the second most abundant element in the Earth’s crust. This is good news for us, considering around 90 to 95% of solar panels on the market are made of crystalline silicon (c-Si).
Silicon has a number of benefits, including its:
- Sheer abundance on the planet, which helps to keep the cost of panels low.
- High conversion efficiency that allows more sunlight to become electricity.
- Nontoxic composition, which makes it a green technology.
- Long lifetime, which in turn allows most warranties for panels to exceed 20 years.
There are two forms of crystalline silicon panels: monocrystalline and polycrystalline. Monocrystalline solar cells consist of wafers cut from one large, pure crystal, and tend to have higher levels of effiency. Polycrystalline solar cells are made by melting multiple crystals together in a vat and are less efficient and less expensive than monocrystalline panels. You can find out more about mono- and polycrystalline panels on our blog post here.
Silicon’s Supporters: Wiring, Glass, and Other Hardware
Where silicon is the powerhouse of the panel, multiple other components are needed to convert and transfer electricity. Busbar ribbon – wiring typically made of aluminum – allows electricity to flow between silicon solar cells. The more busbar ribbon, the greater the efficiency of the panels. High-transmittance glass casing protects the front of the cells, while a backsheet provides electric insulation on the underbelly of the module. A metal frame, usually made of aluminum, holds the panel together, protects the edge of the glass, and allows the modules to be mounted.
Thin Film Panels
Many utility-scale projects use thin film panels, which consist of multiple thin films of semiconductors layered on top of plastic, glass, or metal. Thin film panels are more flexible and about 20 times lighter than crystalline silicon panels. However, they are also generally less efficient. For the average home with limited roof space, crystalline silicon panels’ higher efficiencies make them a more suitable choice.