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.