Light Sustained and Frequency Entrained Photoelectrochemical Oscillations Generated with CuInS2 and CuInSe2 Electrodes

Current oscillations, which can be observed during photoelectrochemistry reduction of hydrogen peroxide at synthetic chalcopyrites (CuMeX2 with Me = Fe, In, X = S, Se) have been induced at p-CuInSe2 by photoexcitation of electrons. It is possible to switch on and off and to gradually control this cooperative phenomenon by varying photon density. The generation of photoelectrochemical oscillations could be triggered and synchronized by means of periodic light or small potential modulation (entrainment of oscillations). It is shown that the controlling factor is the concentration of photogenerated minority carriers (electrons), which, as a thermodynamic force, is determining the distance from equilibrium and bifurcation.