Technological status of Cu(In,Ga)(Se,S)2-based photovoltaics

This report presents a selective overview of the technological status of thin film photovoltaics based on chalcopyrite compound Cu(In,Ga)(Se,S)2 (CIGSSe, or CIGSe if the material does not contain any sulphur) absorber layers. It is not intended to provide a complete list of all active research laboratories or companies in the field, but rather to show the exemplary state of the art of different approaches that are currently pursued to produce low-cost, highly efficient CIGSe or CIGSSe solar cells and modules. For an academic perspective and to assess the potentials, we concentrated on deposition processes leading to highest conversion efficiencies or of special technical interest. On the industrial side, the absorber deposition method was chosen as main differentiator. Highest efficiency values are given to the best of our knowledge and no claim is made for the completeness of the review of all important activities in the field.