ContaCt - Soltecture GmbH

14 | 15 TECHNOLOGYPhotovoltaics of the futureSulfurcell produces thin-film solar modulesbased on semiconductors from the CIS familyIn recent years the number of photovoltaic absorbermaterials has grown and grown. The conventional crystallinesilicon modules have been joined by thin-film solarmodules, which bring benefits for many applications.The thin-film technologies include solar modules madeof CIS semiconductors, like the ones Sulfurcell has beenproducing for years. The Berlin company helped toresearch and develop this groundbreaking photovoltaictechnology and patented it.Thin-film technology based on CIS semiconductors differsfrom other solar modules in that it is environmentallyfriendly from the very outset, i.e., no high-temperatureprocesses have to be applied in production, so the energyconsumption is low and is recaptured during the firstoperating year via the sunlight used. Toxic process gasesand chlorine chemicals are spared. But most important ofall, the production of the modules uses natural resourcessparingly: the glass is coated with a razor-thin layer ofsemiconducting material which converts sunlight intoelectricity. It is thinner than a hair, and a hundred timesthinner than the silicon wafers used for conventionalmodules. The few concerns that the element indium, as ispresent in CIS semiconductors, was too scarce to be usedfor mass production have been scientifically refuted. 1)Indium exists in sufficient quantities in the Earth’s crustand is even found more often than silver.Sulfurcell is working hard to enhance its technologicaledge. To this end, it collaborates with leading researchinstitutes such as the Helmholtz-Zentrum Berlin andthe University of Oldenburg. Under laboratory conditionsCIS semiconductors already reach the highest degree ofefficiency of all the materials used for thin-film modules.CIS technology, a competitive comparisonSemiconductor materialPolycrystallinesilicon moduleModules (wafers)Polycrystalline siliconCIS modulefrom SulfurcellThin-filmCISCuInS 2 , Cu(In,Ga)Se 2 ,Cu(In,Ga)(S,Se) 2Cadmium tellurideCdTe1)See “Indium: Geology, Mineralogy, and Economics”by Ulrich Schwarz-Schampera and Peter M. Herzig,Springer, Berlin (2002).2)Solar efficiency tables, Progress in Photovoltaics,Vol. 15, 425-430 (2007)Amorphous/microcrystalline silicona-Si/µ-Si