Solar panels are made by creating silicon wafers that are layered with dopant materials to create a p-n junction, which generates an electrical current when exposed to sunlight. This technology has been used in everything from calculators to spacecraft!
Solar cells were first discovered in 1884 by Charles Fritts, but it wasn’t until 1954 that scientists at Bell Labs invented the solar cell we know today. The first solar cell was about 1/4 inch thick and produced only 0.5 volts of electricity under ideal conditions – not enough for practical use.
Today’s photovoltaic cells can have up to twenty layers of electrodes and produce over 200 volts, making them more efficient than ever before! It takes about one hour for a solar cell to produce energy equal to that in one AA battery.
Read on to find out more about how solar panels are made.
Solar panels are made from silicon
Solar panels are made from silicon, a semiconductor material, which has properties useful for creating a photovoltaic cell – an object that converts light from the sun into electricity. In order to make a solar panel, you need to create silicon wafers composed of layers of semiconductor materials whose properties allow them to efficiently convert sunlight to energy.
The first step is growing crystals of pure silicon and carving them into thin wafers, or slices. Pure silicon is a semiconductor whose ability to conduct electricity can be limited by adding other materials called dopants. The most common dopant used in pure silicon is phosphorous.
Phosphorous has five electrons in its outer shell whereas elemental silicon only has four electrons available for bonding, so when phosphorous atoms are added, the extra electron from the phosphorous is donated to the silicon and a covalent bond is created between them.
Once a pure silicon wafer has been made, it must be treated with heat in order to expel any non-bonding electrons. Then a thin layer of metal is deposited on top of the wafer. A metal is used as a positive electrode, or anode. Since these metals have fewer electrons than the dopant-silicon wafer bond, they spontaneously donate them to the bond and a covalent chemical bond forms between the two materials.
The next step is adding a protective layer on top of the anode to stop corrosion from occurring. The most common material used is aluminum, which forms an extremely thin layer on top of the silicon wafer.
Then a very thin layer of silicon dioxide is deposited at the wafer surface to protect it from any corrosive effects that might occur when placing into contact with water or oxygen. It also helps keep dirt away from the cells when they are out in the elements.
The final step is adding a thin layer of plastic on top of everything to help protect it from damage or breakage. All together, this process produces an extremely thin solar cell!
Silicon is made from quartz, which is mined from the earth.
To make the wafers, pure silicon is heated until it melts and poured into a semiconductor material composed of small diamond-shaped wells. This entire structure is called a solar cell ribbon.
To make one solar cell, you must carve out three cells from one ribbon by slicing them apart with an extremely sharp knife that fits into the spaces between the cells.
Once the solar cell has been carved out, it must be treated with heat and chemicals to remove any non-bonding electrons and doped with phosphorus to make it a semiconductor capable of producing an electric current. This process is called diffusion.
The next step is adding a thin layer of aluminum on top of the wafer to act as the positive electrode.
After adding the aluminum electrode layer, it’s time to add a thin protective layer on top of everything. This is called the anti-reflective coating and is used to stop corrosion from occurring when exposed to moisture or oxygen in the air. Then an extremely thin sheet of plastic is added over this for protection. You can now see why solar panels are so fragile.
It is now time to test the cells! The electrical properties of each cell are measured by applying a potential across it and measuring the current that flows through it. Cells that do not produce any current or only produce very little are thrown out.
Now you have officially made your own solar cell!
The quartz is crushed and purified to remove any impurities
Silicon is extracted from the quartz by heating it in a furnace until it melts. Crystals of pure silicon are grown in large vats using methods based on how silicon naturally forms in the ground. Most solar cells are made with crystal ingots that are four inches wide and extremely long, up to 40 feet!
The wafers are sliced from the ingots using a circular saw that revolves around two sides of the crystal.
The solar cell ribbon is sliced apart to make individual cells by an extremely sharp knife.
After diffusion, the positive electrode is added in the form of an aluminum layer on top of the wafer. Then a thin protective layer is added for protection.
The purified silicon is then melted and poured into small molds called ingots.
These ingots are then sliced across their width to create the wafers used in solar cells. The wafers must be perfectly smooth and flat or else they will not produce electricity!
A thin layer of aluminum is deposited on top of the wafer to act as the positive electrode. This process is called sputtering, which uses high-powered magnets to target the wafer with molecules of aluminum.
Extremely thin protective and anti-reflective coatings are added on top of everything as well as a layer of plastic for protection.
The ingots are then sliced into thin wafers
The ingots are then sliced into thin wafers using a circular saw. The solar cells are now ready to be tested and sorted by their electrical properties. If they do not produce any current or only produce very little, the cell is thrown out and does not become part of a solar panel.
Only perfectly flat and smooth wafers can be used in solar panels!
The wafers are treated with a special coating that helps them absorb sunlight
The protective and anti-reflective coatings must be perfectly applied to ensure that all of the sunlight is absorbed by the panel, allowing for maximum electricity production!
Conclusion
Solar panels are made up of silicon wafers that are layered with dopant materials to create a p-n junction, which generates an electrical current when exposed to sunlight. By using this technology, we can create renewable energy devices that power everything from calculators to spacecraft!