Electrochemical Synthesis and Characterization of Poly(Rhodamine B) Coating on FTO

Abstract

In this paper we describe the conditions of electrochemical synthesis of a homogeneous and highly adherent pink film of poly(Rhodamine B) (PRhB) on a conducting glass substrate, which facilitates and enables its optical characterization. The electrosynthesis was performed by cyclic voltammetry, galvanostatic and potentiostatic techniques in 0.1 M KCl as supporting electrolytes and 1 mM Rhodamine B (RhB) as monomer on fluorine doped tin oxide (FTO) samples. The anodic peak associated with the RhB oxidation appears at 0.977 V during the first scan and shifts to 1.059 V in the following cycles, indicating the increase in the electrical resistance of the polymer coating until it reaches the overpotential to overcome the resistance. Chronopotentiometry and chronoamperometry show that the PRhB is obtained at applied current densities and potentials higher than 10 μA cm-2 and 0.8 V, respectively and the polymer coating become thicker and darken with increasing the applied current and potential. Electrochemical methods show that the polymer growth is controlled by the maximum oxidation potential applied. The physico-chemical properties of generated PRhB film has been characterized by different microscopic and spectroscopic techniques such as scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and UV–visible spectrophotometry (UV-vis). The produced modified electrode would offer a promising candidate for future applications such as sensors and dye synthesized solar cell.