Solar4Scholars: Make Your Own Solar Cell
You will need:
- A small (2' x 1') sheet of copper flashing (available at your local hardware store)
- An electric stove (a propane torch may also be used)
- A large clear plastic bottle
- Table salt
- Tap water
- Sandpaper (or steel wool)
- Sheet metal shears (also called "tin snips")
- Two alligator clip leads
- A micro-ammeter (available from Radio Shack or other electronics store)
Instructions: How to build a solar cell
- Cut the piece of copper sheeting, so that it fits the stove burner. Clean it first, so that there is no corrosion or other materials. Use the sandpaper.
- Heat the copper sheeting until it is red hot. This will create two kinds of copper oxide: cuprous oxide is the one you are interested in. It will be red or tinges of orange or pink. This will be found underneath the black cupric oxide (which is no use to us). These copper oxides will begin to form after only a few minutes, but let the copper 'fry' for up to half an hour, forming a fairly thick coat of cupric oxide.
- Turn off the stove and let the copper flashing cool slowly. The copper will shrink as it cools, and some or most of the black cupric oxide will actually pop off. Remove the copper from the stove element, once it has cooled (after about 20 minutes).
- Lightly clean or rub the copper flashing with the sandpaper, under running tap water if you wish. Remove the cupric oxide but be sure to not remove much of the cuprous oxide.
- Cut another piece of copper about the same size as the first. Bend both pieces of copper and set them inside the jar or bottle, making sure they are not touching. Connect the two plates to the ammeter. Connect the plate with cuprous oxide to the negative terminal and the clean plate to the positive terminal. You now have a solar cell, with a charge being read on the micro-ammeter.
Test your panel
Take your solar cell out into the sunlight and watch the micro-ammeter jump. In shade, you will get very low micro-amperage, but in the sunlight, it should jump to 50 or higher.
Alternate method: use silvering to cover one side of the copper sheeting, after you have created a side with cuprous oxide. Instead of using alligator clips, solder a wire to each side of the panel, one on the oxidized side and the other on the silvered side.