Keywords: nanocrystalline TiO2, photoelectrodes, dye–sensitised solar cells, DSSC, nanotechnology, gold nanoparticles, ITO glass substrate, indium tin oxide, titanium dioxide, titania
Effect of Au nanoparticles added in nanocrystalline TiO2 film on the photoelectrode of dye–sensitised solar cells
In this study, we used a citrate reduction method and electrophoretic deposition (EPD) to prepare hybrid nanocrystalline TiO2/Au films and applied it to the photoelectrode of dye–sensitised solar cell. The films and solar cells were investigated by field emission scanning electron microscopy (FE–SEM), energy dispersive X–ray analysis (EDX), X–ray diffraction (XRD), I–V characteristics and electrochemical impedance spectroscopy (EIS) analyses. In the FE–SEM analysis, TiO2/Au hybrid layers have the porous structure that is advantageous in the dye–loading capacity. The results of EDX reveal that the TiO2/Au hybrid layer contains 0.28 wt% gold nanoparticles. X–ray diffraction patterns show that the TiO2/Au hybrid films contain TiO2 anatase and rutile phase, and Au peaks. Under sunlight simulator (AM 1.5 100 mW/cm²) illumination, the conversion efficiency of dye–sensitised solar cell with TiO2/Au hybrid layer is obviously higher than that of TiO2 film. In the analysis of electrochemical impedance spectroscopy (EIS), the total impedance of hybrid TiO2/Au photoelectrode is 98.9 Ω, which is lower than that of TiO2 film photoelectrode. These results indicate that TiO2/Au hybrid layer can increase the conductivity and reduce the recombination of charges in the photoelectrode, resulting in the increase in conversion efficiency for DSSCs.