IN-SITU COMBINED ELECTROCHEMICAL SURFACE PLASMON RESONANCE STUDY OF ULTRA-THIN PRUSSIAN BLUE FILMS DEPOSITED ON GOLD ELECTRODES

摘要

This paper reports on the characterisation of ultra-thin Prussian Blue films using in-situ combined Electrochemical Surface Plasmon Resonance technique. Prussian Blue films were prepared, by potentiostatic method, on a gold-coated glass Surface Plasmon Resonance sensor. The electrochemical redox processes of Prussian Blue, i.e., the reduction of Prussian Blue to Prussian White and the oxidation to Berlin Green, are accompanied by a change of the refractive index. The changes in the Surface Plasmon Resonance signal, during potential cycling on Prussian Blue films, are more pronounced for the Prussian Blue/Prussian White system than for the Prussian Blue/Berlin Green system. Due to the strong absorbance of Prussian Blue film in the sensing region of the instrument, only a qualitative characterization has been achieved. The in-situ combined Electrochemical Surface Plasmon Resonance technique is capable of evidencing minute changes of the oxidation state of the film and adsorption processes on electrode surface.