Studies on the electrochemical stability of CIGS in H2SO4

In this work, we investigated the performance of Cu(In,Ga)Se-2 (CIGS) based photo-electrodes in a solid-liquid electrochemical system. The stability studies related to photocorrosion and dissolution of the photo-electrode in 0.5 M sulfuric acid medium were carried out using electrochemical methods based on linear and cyclic voltammetry. The stability of the CIGS-PVD/H2SO4 system like the semiconductor/electrolyte interface was investigated as a function of time. It is an alternative procedure instead of the usual Tafel slope analysis. A small external signal with a low value of scan rate was applied in the electrochemical interface for promoting redox reactions on the surface of the semiconductor. The semiconductor/electrolyte system was analyzed for 12 days. The samples were analyzed using SEM and EDS. The results showed morphological changes on the sample surface but without substantial change in the chemical composition. It is likely that Cu2+/Cu+ is dissolving in the electrolyte and then re-adsorbed by the semiconductor surface. (C) 2004 Elsevier B.V. All rights reserved.