Overview of Thin-Film Solar Cell Technologies

Abstract After 35 years of continuous research and development, thin-film photovoltaic materials like amorphous silicon in various combinations and the compound polycrystalline semiconductors Cu(In,Ga)(Se,S)2 (CIGS) and CdTe have shown continuous progress and all of them have started major industrial activities since the beginning of this century. Fundamental R&D has shown exciting progress in recent years for CIGS and CdTe, whereas amorphous silicon laboratory solar cell efficiencies are still below 15%, despite 10 years of intensive research activities worldwide. CIGS champion efficiencies approaching 21% have been shown by several groups and CdTe recently also showed champion cell efficiencies in the same range. Both materials have already shown cost leadership in few large volume production lines and have the ability to reach production costs well below 0.4 US$/W in medium term.