Enhanced Photoelectrochemical Performance of Nanocomposite Film Fabricated by Self-Assembly of Titanium Dioxide and Polyoxometalates

Abstract

In order to fabricate photoelectrochemical devices, multilayer films composed of positively charged titanium dioxide (TiO2) colloids and anionic tungsto(molybdo)phosphate (PW12 and P2Mo18) or poly(styrenesulfonate) (PSS) have been prepared by the layer-by-layer (LbL) self-assembly method. These films were characterized by UV−vis spectroscopy, IR spectra, and atomic force microscopy. Photocurrent transient measurement suggested that the photocurrent response of the PW12/TiO2 composite film was highly dependent on film thickness (viz., the deposited number of layers). Both current−voltage curves and photocurrent transient measurement demonstrate that the photocurrent and power conversion efficiency of the PW12/TiO2 composite film were markedly enhanced in comparison with that of the P2Mo18/TiO2 film and the PSS/TiO2 film. Furthermore, the PW12/TiO2 composite film also exhibited the most significant photoelectrooxidation activity for methanol. These results provide valuable information for photovoltaic and photoelectrochemical applications.