Electrochemical treatment of CuInS2

We present a novel method to remove the unwanted covellite (CuS) in Cu-rich prepared CuInS2-CdS-ZnO photovoltaic cells by a combined chemical/electroc hemical procedure. Our treatment results in a solid state transformation by electrochemical reduction in an alkaline electrolyte with subsequent chemi cal dissolution. The reduction is carried out in the potential range betwee n - 1.1 and - 0.85 V vs. a saturated calomel electrode (SCE). In situ atomi c force microscopy (AFM) confirms a distinct change in morphology. The chem ical and electrochemical reactions leading to the dissolution are discussed . After completion of the treatment a pronounced photoeffect is observed. X -Ray diffraction (XRD) shows the complete removal of CuS, (C) 2001 Elsevier Science B.V. All rights reserved.