A second-generation process for high-efficiency large-area Cu(In,Ga)(Se,S)(2) thin film (CIGSSe) solar modules has been developed applying controlled sodium doping and rapid thermal processing for absorber formation. The pilot line delivers aperture area efficiencies of 12.2% +/- 0.5% (average) for 30 x 30 cm(2) modules and a certified champion efficiency of 13.1 % for an unencapsulated 60 x 90 cm 2 demonstrator module. The stability of the frameless pilot line modules with a low-cost package against humidity is confirmed externally by passing the damp heat test sequence according to IEC 61646. Substitution of CBD-CdS by CBD-Zn(S, OH) buffer layers yields efficiencies up to 12% on 30 x 30 cm2 circuits. First CIGSSe-cells on flexible substrates were also developed applying 30 mu m thin titanium foils, 8 x 8 cm(2) in size. Average cell efficiencies on a substrate up to 12.4% were achieved. (c) 2006 Published by Elsevier B.V.