Photovoltaic cells consist of several thin films made of semiconductors. Worldwide the silicon is almost always (98%) used as a basis material for solar cells manufacture. Silicon offers the advantage of being the second most frequent available element on the earthcrust and environmentally friendly. According to the manufacture procedure, one distinguishes three types of silicon photovoltaic cells: monocristallin, multicristallin and amorphous photovoltaic cells.

While for cristallin cells usually a pulled and/or poured silicon crystal is sawed and then in disks processed, amorphous cells are steamed up on a carrier material with less material and energy cost . Generally these less materially costly cells are named thin film photovoltaic cells. Non -silicon cells are made as well by semiconductors as for exemple copper-Indium-Diselenid (CIS) cells.

The functional method of a photovoltaic cell under solar radiation is schematically represented in the following picture. For all kind of photovoltaic cells the same tension respectively same current is always produced.

(Solar Power Box, TNC Consulting AG, 8703 Erlenbach, www.tnc.ch)