Cationic surfactant promoted reductive electrodeposition of nanocrystalline anatase TiO2 for application to dye-sensitized solar cells

A new strategy involving the introduction of the common cationic surfactant cetyltrimethylammonium bromide (CTAB) for the cathodic deposition of titanium dioxide from hydrolyzed TiCl4 and TiCl3 solutions by cyclic voltammetry has been developed. Crack-free and non-transparent anatase TiO2 films were obtained for the first time and characterized with the aid of Raman spectra and SEM. Selection of TiCl4 as the precursor for the electrodeposition is quite a novel approach for the research in the area of dye-sensitized solar cells (DSSCs). It is noted that NO3− ion is essential for such a deposition. Under the same conditions, a thicker TiO2 film was obtained by adding CTAB into KNO3 electrolyte, compared with the case without it. The CTAB-promoted film led to an increased energy conversion efficiency of the corresponding DSSC. Mechanisms are proposed for the electrochemical deposition and the beneficial role of CTAB.