Non-vacuum processing of CuIn1−xGaxSe2 solar cells on rigid and flexible substrates using nanoparticle precursor inks

Abstract A novel non-vacuum process in which water based inks formulated using nanoparticles of mixed oxides of Cu, In and Ga are used to deposit a precursor layer of fixed Cu/(In+Ga) ratio on a rigid or a flexible substrate of choice using printing techniques. The precursor layer is converted to a CuIn 1− x Ga x Se 2 (CIGS) absorber layer of uniform composition via two sequential gas solid reactions of reduction and selenization. Solar cells fabricated in CIGS films prepared by this technique have conversion efficiency approaching 13.6% on glass substrate and over 10% on Mo foil. Compositional uniformity, high materials’ utilization and the use of low-cost equipment make this process suitable for large-scale production of low-cost CIGS modules.