Crystalline silicon provides efficient but costly conductor for PV cells

Photovoltaic systems convert sunlight directly into electricity. The solar energy knocks electrons loose from their atoms, allowing the electrons to flow through a semiconducting material to produce electricity.

Crystalline silicon was the original semiconductor material used by the PV industry and is still used in 90 percent of solar cells. Silicon's orderly atomic structure allows electrons to shoot rapidly through the crystal to the electrodes. Organic materials like light-absorbing polymers are cheaper and easier to process, but their atomic structure does not conduct electrons as efficiently as silicon.

Despite substantial advances in PV production technology, the cost of crystalline PV modules remains high because of high materials costs and because many processing steps are needed to manufacture the modules. Conventional crystalline silicon solar cells are fabricated in a step-and-repeat batch process from small wafers of single crystal or polycrystalline silicon semiconductor materials.