What Are Solar Panels Made Of?
A typical solar panel is a sandwich of six main parts: silicon photovoltaic cells, tempered glass, EVA encapsulant, a polymer backsheet, an aluminium frame, and a junction box. Over 95% of the panel by mass is silicon, aluminium, and glass — all recyclable materials.
Quick Answer
Solar panels are made of silicon cells (the part that generates electricity), tempered glass on top, EVA plastic encapsulant, a polymer backsheet, an aluminium frame, and a junction box. A typical 440W panel contains around 2–3 kg of silicon, 15 kg of glass, and 2 kg of aluminium.
The 6 layers of a solar panel
Tempered glass (top layer)
3.2mm thick low-iron tempered glass protects the cells from hail, rain, UV, and debris. Low-iron lets more light through (92%+ transmission) than standard glass. Weighs around 7–8 kg/m².
EVA encapsulant (top)
Ethylene-vinyl acetate film seals the cells between the glass and backsheet, prevents moisture ingress, and transmits light to the cells. Typically 0.45mm thick.
Silicon photovoltaic cells
The active layer. Typically 144 half-cut monocrystalline silicon cells, each about 182mm × 91mm. Modern cells use N-type TOPCon technology for higher efficiency (22%+) and lower degradation than older P-type PERC.
EVA encapsulant (bottom)
Second EVA layer below the cells, sealing them against the backsheet.
Polymer backsheet
Three-layer fluoropolymer film (typically Tedlar or similar) provides electrical insulation and weatherproofing. Some premium panels use a second glass sheet instead — called "glass-glass" or bifacial panels.
Aluminium frame + junction box
Anodised aluminium frame (around 2 kg per panel) provides structural rigidity and mounts to roof rails. A sealed junction box on the back contains bypass diodes and the output wires with MC4 connectors.
What kind of silicon is used?
The silicon in solar panels starts as purified silicon — the same element as sand (silicon dioxide), but refined to 99.9999% purity ("six-nines" or solar-grade silicon). It is then cast into ingots and sliced into thin wafers around 180 microns thick.
Modern UK panels use monocrystalline silicon, where the entire cell is grown from a single crystal. This produces the highest efficiency (22%+). Older polycrystalline panels (darker blue colour, made of multiple crystals) are now rarely sold — they top out around 18% efficiency and are being phased out.
See our solar panel types guide for a full comparison of monocrystalline, polycrystalline, and thin-film technologies.
Are solar panel materials recyclable?
Yes — over 95% of a solar panel by mass is recyclable:
- Glass (~75% of panel weight): easily recycled into new glass products
- Aluminium frame (~10%): fully recyclable and high-value
- Silicon cells (~5%): can be stripped and reprocessed into new wafers
- Copper wiring (~1%): high-value recyclable
- Silver conductive paste (~0.05%): recoverable, though the volume is small
- EVA encapsulant + backsheet (~7%): harder to recycle; typically incinerated or landfilled
In the UK, panels fall under the WEEE (Waste Electrical and Electronic Equipment) Directive. Installers are legally required to take back end-of-life panels for recycling. See our solar panel recycling guide.
Frequently Asked Questions
What is the main material in solar panels?
Silicon. The photovoltaic cells that generate electricity are made of ultra-pure silicon wafers. By mass, glass is the largest component (around 75%), with silicon contributing around 5% of total weight but 100% of the electrical output.
Are solar panels made of glass?
The top layer is tempered glass — typically 3.2mm of low-iron glass that lets 92%+ of light through. "Glass-glass" panels use a second glass sheet on the back instead of a polymer backsheet.
Do solar panels contain rare earth elements?
No. Silicon solar panels do not contain rare earth elements. They contain silicon, aluminium, glass, copper, and small amounts of silver — all widely available materials. Rare earths are used in some wind turbines and EVs but not in PV panels.
Are solar panels toxic?
Standard silicon panels are not toxic and can be safely installed and disposed of. Some older thin-film panels (CdTe, CIGS) contain small amounts of cadmium, which requires controlled disposal — but these are rarely used for UK residential installations.
What is the lifespan of solar panel materials?
Modern panels last 25–30 years with less than 0.5% annual output degradation. The aluminium frame and glass can last 50+ years. The EVA encapsulant is the first to age — yellowing after 25–30 years can reduce transmission.
Related technical guides
Related Guides
Solar Panel Types
Monocrystalline, polycrystalline, thin film, bifacial, and IBC panels compared.
How Solar Panels Work
Plain-English guide to solar PV technology.
Solar Panel Lifespan
How long solar panels last, degradation rates, and warranties.
Solar Panel Recycling
WEEE regulations, recycling centres, disposal costs, and material recovery.
Sources
- IEA PVPS — End-of-Life Management of PV Modules — iea-pvps.org
- Fraunhofer ISE — Photovoltaics Report — ise.fraunhofer.de
Last updated: April 2026
Fact-checked by John Rooney, Solar Energy Editor. Editorial policy
John Rooney is the founder of Solar Info and has been covering the UK solar energy market since 2023. He fact-checks all content against official MCS and Ofgem data and maintains relationships with MCS-certified installers across the UK.
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