Significant enhancement of power conversion efficiency of dye-sensitized solar cells by the incorporation of TiO2-Au nanocomposite in TiO2 photoanode

In this report, the effect of incorporation of hydrothermally prepared TiO2–Au nanocomposites in the photoanode of dye-sensitized solar cells (DSSCs), prepared from commercially available TiO2 nanoparticles, has been investigated. Electrophoretic deposition technique has been utilized for nanocompositedoped photoanode preparation. The formation of hydrothermally prepared TiO2–Au nanocomposites has been confirmed by the X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), UV–Vis spectroscopy. The HRTEM images establish that the particle size of Au nanoparticles dispersed in TiO2 matrix varies from 2 to 45 nm. TiO2–Au photoelectrode has been characterized by XRD, field emission scanning electron microscopy, Raman spectroscopy and photoluminescence spectroscopy in order to confirm the successful preparation of plasmonic photoanodes. Measurement of current– voltage characteristics of the plasmonic dye-sensitized solar cells under the solar simulator illumination (100 mW/cm2, AM 1.5) shows enormous enhancement of power conversion efficiency. The PCE of plasmonic DSSCs is 10.1%, which is 134% greater than the DSSCs with pristine TiO2 photoanode of the same thickness. Electro-impedance spectroscopy reveals that the back electron transfer from the conduction band of Au–TiO2 photoanode to either dye or electrolyte has been significantly suppressed in the DSSC with plasmonic photoelectrode.