Things you need
- A copper sheet (a half square foot will be enough)
- Two alligator clip leads
- A sensitive micro ammeter that is capable of reading currents between 10 and 50 microamperes. (Small surplus meter with a needle can be used).
- An electric stove(an 1100 watts burner should be used)
- A larger clear plastic bottle off whose cap could be cutt. You can use2 liter spring water bottle. A large mouth glass jar can also be used.
- Table salt (a couple of tablespoons).
- Tap water.
- Sand paper or a wire on an electric drill
- Sheet metal shears for cutting the copper sheet.
Building of solar cell
Cut a piece of the copper sheet same size of the burner on the stove. You must wash hands in order to avoid grease or oil on them. Wash the copper sheet with the help of soap or cleanser to get rid of grease or oil fromit. You should use the sand paper or wire brush to clean the copper sheating in detail so that the sulphide or other light corrosion is detached. It dries properly.
Place the dried copper sheet on the burner and set the burner on its highest point.
As the copper is heated beautiful orange red and purple oxidation patterns appear on it.
Keep on heating the copper the colors are replaced with a black coating. This black coating indicates that oxidation has take place and has resulted in the formation of cupric oxide. We don’t want the oxide but will peel it off later. The last spots of color will vanish as the burner starts to glow red making the copper into pure black sheet. When the burner glows red hot the sheet of copper will be covered fully with a black cupric oxide coat. At this stage we have to cook it for another half an hour, so that the black coating will be thick. It is important to have a thick coating because it will flake off easily as compared to a thin coating. This fixes to the copper.
After cooking for half an hour turn off the burner. Allow the burning copper cool slowly; cooling it quickly the black oxide will stay fixed to the copper.
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solar-cell system |
On cooling the copper reduce in size all along with the black cupric oxide but they both reduce at different rates which makes the black cupric flake off easily.
When the copper cools to room temperature (in 20 mints) most of the black oxide will flake off and the rest could be removed by light scrubbing with the hands under running water.
Slice another sheet of copper of the same size as the first one. Bend both pieces lightly in a way that they fix in the plastic bottle or jar without touching one another. The cuprous oxide coating which was faces the upper side of the burner is the best side to face outwards in the jar because it is smoother and cleaner surface.
Put together the two alligator clip directs to the new copper plate and the other to the cuprous oxide coated plate. Join the lead from the positive terminal of the meter at one end and with the clean copper plate to the other. Join the other leading from the cuprous oxide plate to the negatively charged terminal of the meter.
Mix a couple of tablespoon of salt into hot water. Stir the salt water until the salt is dissolved totally and mixture looks homogeneous. Pour the salt water into the bottle or jar carefully, make sure that clips don’t get wet. The salt water should not come over the plates there should be a gap of about an inch of plate on top of the water so that you can shift the cell around without getting the clip leads wet.
