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Currently, crystalline silicon is the semiconductive material most commonly used in commercial photovoltaic cells. Under normal conditions, a silicon molecule has four outer electrons (valence) that bond it together in a crystal. However, when a silicon molecule is exposed to the energy of the sun these electrons absorb the photon's energy and break loose from the solar crystal. The photovoltaic cell is designed to capture these freed electrons in an external circuit. As the freed electrons flow through the circuit they give up their energy as useful work (that can be stored in a battery). The electrons then flow back to the solar cell.

Other types of photovoltaic cells employ a thin film of semiconductive material such as amorphous silicon or cadmium telluride, or materials such as gallium arsenide and its alloys.