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

摘要

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 nanocomposite-doped 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/cm(2), 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.