Abstract
Nanoclustered TiO2 networks were synthesized hydrothermally one-step in 0.45 M tetramethylammonium hydroxide (TMAOH) aqueous solution directly on pure polished Ti substrate for 12-hour growth. Polypyrrole (PPy) nanofilm was subsequently electropolymerized with galvanostatic photo-anodization on the nanostructured TiO2 sheet as the working electrode. Tafel polarization curve was employed to determine galvanostatic condition. Investigations of SEM, cyclic voltametry, potential-time growing curves, photo-response currents, UV-vis spectroscopy and Fourier Transform Infra-red (FTIR) spectroscopy revealed that photo-anodic polymerized pyrrole film could thoroughly change properties of nanoclustered TiO2 electrode. The networks of nanoclustered TiO2 was covered with homogeneous PPy nanofilm, the cyclic voltammetry revealed two reduction peaks, suggesting a compact and a porous layer of PPy. Moreover, PPy could enhance the photo-response by over 100 times compared with that of bare TiO2 nanonetworks. Optical absorbance visualized the full spectral absorptive feature of PPy, and FTIR further confirmed the vibrations of chemical bonds from PPy. This demonstrated that PPy infiltration in TiO2 nanonetworks could be successfully achieved via photo-anodic polymerization, and TiO2 nanonetworks/photo-anodic polymerized PPy are promising in applications of polymer-inorganic solar cell.