Solar PV, or photovoltaic, panels convert the power of the sun’s light into electricity. They are made up of many individual solar cells, wired together to increase their power. Solar cells that are made for commercial production are fashioned out of specially prepared silicon wafers and glass. This process is too difficult and expensive for the amateur to replicate at home. However, you can build a different, simpler, though less-efficient one at home out of other materials for a science-fair project.
Things You'll Need
- 2 small flexible copper sheets
- Fine grit sandpaper
- Electric stove
- 2 liter plastic soda bottle
- 1 liter measuring cup
- Multimeter with alligator clip leads
Wash your hands to remove any dirt and grease. Scrub two small copper sheets with sandpaper to remove the thin layer of oxides that coat any metal that is in contact with air.
Put one of the copper sheets onto the burner of the electric stove. Turn the burner to its highest setting and let it heat up. It will first turn orange, red and purple, and then finally black. The black substance is cupric oxide. Heat the sheet for 30 minutes after it has turned black in order to thicken the coating of cupric oxide.
Turn off the burner and let the copper sheet cool to room temperature. As it cools it will shed much of the cupric oxide that had formed. Once it is cool, scrub it gently under running water to remove the rest of the cupric oxide. It is better to leave some black spots than scrub too hard. The sheet should now have a reddish color, which is cuprous oxide. It reacts to sunlight much as the silicon of the commercial cells does.
Cut a plastic bottle in half with a knife. Gently bend both of the copper sheets so that they can fit into the bottle. Put them in the bottle in such a way that they do not touch each other.
Pour about 1 liter of hot water into a measuring cup. Slowly pour salt into the water, mixing as you pour. Once the salt stops dissolving, the water is completely saturated. Pour this salt solution into the bottle with the copper sheets. Leave about an inch of the sheets protruding above the water.
Set a multimeter to read DC current at its lowest level. Clip the positive terminal lead of the multimeter to the top of the clean copper sheet. Clip the negative terminal lead to the other sheet. Place the cell in direct sunlight. The multimeter should show that your cell is generating as much as 50 microamps of current. Switch the multimeter to read DC voltage, and you should see approximately ¼ volt.
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