--- title: "What is a Solar panel made of?" description: "Doped silicon wafers with silver contacts, sealed between low-iron glass and a plastic backsheet in an aluminium frame. Every component, the material it uses, and th" url: https://atoneplace.net/made-of/solar-panel/ site: "At One Place" --- # What is a Solar panel made of? **What is a Solar panel made of?: Doped silicon wafers with silver contacts, sealed between low-iron glass and a plastic backsheet in an aluminium frame.** By mass a panel is mostly glass and aluminium, and the silicon is a small fraction — which is why panels are heavy, why they are cheap, and why recycling them recovers a lot of low-value material and a little high-value silver. Output degrades slowly and predictably, typically a few tenths of a per cent a year, and warranties are written around 80-85% of rated output at 25 years. The other thing worth knowing is that panels lose efficiency as they get hot: rated power is measured at 25 °C cell temperature, and a roof panel in summer sun routinely runs 20-30 °C above ambient, so a cold bright day can outproduce a hot one. ## Component by component *Every material is a choice, and the third column is the constraint that drove it.* | Part | Material | Why that material | | --- | --- | --- | | cells | crystalline silicon wafers doped with boron and phosphorus | The junction between the two doped layers is what separates light-generated charge; silicon is abundant and its bandgap suits sunlight well. | | contacts | screen-printed silver paste fingers and busbars | Silver is the best conductor and prints finely, and it is the material cost the whole industry works hardest to reduce. | | encapsulant | ethylene vinyl acetate film, laminated under vacuum | It bonds the stack and keeps moisture off the cells; when it yellows or delaminates, output falls and the panel is finished. | | front glass | low-iron tempered glass, 3-4 mm | Iron gives ordinary glass a green tint that absorbs useful light; low-iron glass transmits a couple of per cent more. | | backsheet and frame | a fluoropolymer-PET laminate or a second glass sheet, in an anodised aluminium frame | The frame carries the wind and snow load; glass-glass panels last longer but weigh considerably more. | | junction box | a sealed box with bypass diodes | Without bypass diodes, one shaded cell would throttle the whole string and heat up dangerously as a resistor. | ## Other electronics objects - [Alkaline battery](https://atoneplace.net/made-of/alkaline-battery/) — Zinc powder and manganese dioxide either side of a potassium hydroxide paste, in a steel can. - [Smartphone screen](https://atoneplace.net/made-of/smartphone-screen/) — Chemically strengthened aluminosilicate glass over a touch layer and an OLED or LCD panel, with an oil-shedding coating on top. - [LED bulb](https://atoneplace.net/made-of/led-bulb/) — Blue LED chips under a yellow phosphor, plus a driver circuit and a heat sink — and it is the driver that dies. - [Touchscreen](https://atoneplace.net/made-of/touchscreen/) — A grid of transparent electrodes measuring the tiny capacitance your finger adds — which is why gloves fail. - [Computer keyboard](https://atoneplace.net/made-of/keyboard/) — ABS or PBT keycaps over either a silicone rubber dome on printed film, or individual mechanical switches. - [Headphones](https://atoneplace.net/made-of/headphone/) — A neodymium magnet, a coil of copper wire and a thin plastic diaphragm — a loudspeaker shrunk to fit an ear. - [Loudspeaker](https://atoneplace.net/made-of/speaker/) — A paper or plastic cone hung on a rubber surround, driven by a coil in a magnet gap. - [Computer mouse](https://atoneplace.net/made-of/computer-mouse/) — An ABS shell around a tiny camera taking thousands of pictures a second, plus two clicky microswitches and PTFE feet. ## Common questions ### What is a Solar panel made of? Doped silicon wafers with silver contacts, sealed between low-iron glass and a plastic backsheet in an aluminium frame. ### What is the cells of a Solar panel made of? Crystalline silicon wafers doped with boron and phosphorus. The junction between the two doped layers is what separates light-generated charge; silicon is abundant and its bandgap suits sunlight well. ### What is the contacts of a Solar panel made of? Screen-printed silver paste fingers and busbars. Silver is the best conductor and prints finely, and it is the material cost the whole industry works hardest to reduce. ## Related pages - [Alkaline battery](https://atoneplace.net/made-of/alkaline-battery/) - [Smartphone screen](https://atoneplace.net/made-of/smartphone-screen/) - [LED bulb](https://atoneplace.net/made-of/led-bulb/) - [Touchscreen](https://atoneplace.net/made-of/touchscreen/) - [Computer keyboard](https://atoneplace.net/made-of/keyboard/) - [Headphones](https://atoneplace.net/made-of/headphone/) - [Loudspeaker](https://atoneplace.net/made-of/speaker/) - [Computer mouse](https://atoneplace.net/made-of/computer-mouse/) - [Pencil](https://atoneplace.net/made-of/pencil/) - [Tennis ball](https://atoneplace.net/made-of/tennis-ball/) - [Banknote](https://atoneplace.net/made-of/banknote/) - [Golf ball](https://atoneplace.net/made-of/golf-ball/) - [Paper](https://atoneplace.net/made-of/paper/) - [Glass](https://atoneplace.net/made-of/glass/) ## Sources - Typical range compiled from manufacturer specifications — At One Place (/about/)