Over 95 % of all the solar cells produced in the world consist of the semiconductor material silicon (Si). Silicon has the advantage of being available in sufficient amounts as it is the second most common element in the Earth’s crust. Moreover, the crystal can be processed in an environmentally compatible way.

There are three cell types, depending on the type of crystal: monocrystalline, polycrystalline and amorphous. The different cell types differ in terms of their production costs and the different efficiency values. The efficiency values of amorphous cells ("thin-film cells") are below those of the other two cell types; but then they are cheaper due to the less cost-intensive manufacturing process.