Photoacoustic characterization of highly porous, polycrystalline TiO{sub}2 electrodes fabricated with different applied voltage treatments

摘要

We report the effect of voltage on a concentrated KCI electrolyte applied to highly porous, polycrystalline TiO{sub}2 films on the photoacoustic (PA) and photoelectrochemical (PEC) current spectra. The PA signal intensities of the TiO{sub}2 films with the different applied voltage treatments are higher than that without the treatments below the band-gap region, suggesting an inner-band transition due to an increase of carrier concentration by the voltage treatments. The PA intensity below the band-gap region increases with the increase of the applied voltage, indicating the increase of the carrier concentration. The PEC spectra for the applied voltage treatments with -1.5 V and without the treatments show broad bands at approximately around 3.31 eV. The PEC spectra for the applied voltage treatments over -1.5 V show two peaks at approximately around 3.31 eV and 3.88 eV. The intensities of the each peak positions increase rapidly above the applied voltage of -1.5 V. The increase of the PEC intensity with the different applied voltage treatments implies an increase carrier concentration due to donor levels formation by the treatments.