Band edge shifts of p-type copper indium diselenide electrodes in aqueous electrolytes

Impedance measurements were used to evaluate the relative band edge positions of single crystal p-CuInSe2 electrodes in various aqueous electrolytes, by measuring the extrapolated flatband potentials, Vfb. We find that Vfb can be shifted, depending on the extent of the potential scan and on the pH of the electrolyte used, over a range of up to 1.7 V (between pH 0–pH 14). In the pH range 0–6, Vfb can be fixed at intermediate values, which, in their turn, are determined by the pH of the electrolyte.