Using different glass substrate types the Na content in sequentially and Cu-rich prepared CuInS2 films and corresponding CuInS2/CdS/ZnO thin-film solar cells is varied. The purpose was to investigate the influence of different Na concentrations on absorbers and devices. While the morphology of the absorbers seems not to be affected by this variation, corresponding PL spectra differ significantly. The properties of the solar cells, however, show no dependence on the Na concentration. This implies that even though the defect chemistry of CuInS2, sequentially prepared under Cu excess, is changed by the presence of Na this influence has no impact on properties of corresponding solar cells. (C) 2001 Elsevier Science B.V. All rights reserved.