Adsorption Dynamics of Redox Active Species onto Polarized Surfaces of Sensitized NiO

Mesoporous NiO films were deposited by means of a screen printing technique onto fluorine-doped tin oxide transparent electrodes and consequently sensitized with Erythrosin B (EryB) dye. The obtained colored NiO material was used as a working electrode in a three-electrode cell to study the evolution of the triple semiconductor/dye/electrolyte interface upon electrochemical polarization in dark conditions. The electrolyte was a solution of I3–/I– in acetonitrile, with the redox couple representing the typical redox shuttle of dye-sensitized solar cells (DSCs). The adopted electrochemical conditions were devised in order to simulate the actual electrical environment of the NiO/dye photocathode in a light-soaked DSC. The use of a benchmark sensitizer EryB and of the most widely used redox mediator I3–/I– is particularly meaningful for the study of the adsorption dynamics and the determination of possible degradative phenomena on the basis of the behavior of numerous analogue systems. Therefore, for the firs...