Abstract: The present invention provides strategies for making high quality CIGS photoabsorbing compositions from sputtered precursor film(s). The precursors are converted into CIGS photoabsorbing material via a chalcogenizing treatment (also referred to as “post-chalcogenization,” including, e.g., “post-selenization” when Se is used and/or “post-sulfurization” when S is used) using techniques that allow the post-chalcogenizing treatment to occur under atypically low pressure conditions. Consequently, the strategies of the invention are readily incorporated into batch processes or continuous processes such as roll-to-roll process occurring under vacuum. The present invention is useful at lab, pilot plant, and industrial scales.

Abstract: A multi junction photovoltaic device is disclosed. In certain examples, the device includes an upper photovoltaic cell comprising a first plurality of layers of films, including a first active layer of a chalcogenide having a first lattice constant and first energy band gap, and a lower photovoltaic cell disposed below the upper photovoltaic cell and adapted to receive photon radiation passing through the upper photovoltaic cell, and comprising a second plurality of layers of films, including an active second layer of a IB-IIIA-chalcogenide having a second lattice constant and a second energy band gap. The first lattice constant differs from the second lattice constant by no more than about 10%. The first energy band gap can be greater than the second energy band gap by at least about 0.5 eV, or 0.6 eV, or 0.7 eV.