Optical, electrical and photoelectrochemical characterization of electropolymerized poly methylene blue on fluorine doped tin oxide conducting glass

Highlights: • PMB polymer was successfully electropolymerized on (FTO). • Thin and adherent layer of 100 nm and 103 S cm−1electrical conductivity order. • Absorption spectra of the polymer permit to estimate the gap. • HOMO and LUMO energetic levels were calculated. • PMB polymer films generate considerable photocurrents under monochromatic light. -- Abstract: This paper describes the poly methylene bleu (PMB) electrodeposition on fluorine doped tin oxide (FTO) conducting glass and its optical, electrical and photoelectrochemical characterization. The deposited film shows a good electric conductivity which is well confirmed by the low gap value determinated optically by UV–vis spectroscopy. Like all polymers the PMB presents an absorption difference in the visible range function of the polarization potential, it is expressed by the strong conjugation at oxidized state but is weakened with leucoform formation at reduced state. The electrochemical behaviour of the film allows us, to confirm the polymerization of the methylene blue (MB), to observe the oxidation and the reduction states of as prepared layer and to locate the energy levels HOMO and LUMO of this polymer. A photocurrent of some μA has been observed when the film is photosensitized with white light source