Homemade Solar Panels
This shows a simple demonstration of how a homemade solar panel can be used to show the photoelectric effect making electricity from light. Making a solar panel this way would be no where near good enough to generate useful free energy for powering a home, but it great for demonstrating scientific principles.
One sheet of copper is given a coating of cupric oxide as this semiconductor will convert sunlight into electricity. To do this a copper sheet is heated over a hob for around 30 minuets. When the sheet has turned black it is allowed to cool. As it cools down the black copper oxide will start to crack up and come off. this is because the materials underneath are contracting at a different rate. it is usually necessary to finish removing some of the black copper oxide by hand.
The remaining layer is covered with cupric oxide which is the important material for producing the photoelectric effect.
If the copper sheets are placed in a strong salt solution in the arrangement shown above, a small voltage will appear between the two sheets. The salt water is really just meant as an electrical conductor, but it also has the effect of making the device operate like a battery. this means it still generates small amounts of electricity even in the dark.