Title: Effect of Au nanoparticles added in nanocrystalline TiO2 film on the photoelectrode of dye-sensitised solar cells

Authors: T.H. Meen; C.J. Huang; S.M. Chao; N.Y. Lin; W.R. Chen; J.K. Tsai; T.C. Wu

Addresses: Department of Electronic Engineering, National Formosa University, Yunlin 632, Taiwan ' Department of Applied Physics, National University of Kaohsiung, Kaohsiung 811, Taiwan ' Department of Electrical Engineering, Hsiuping University of Science and Technology, Taichung 412, Taiwan ' Institute of Electro-Optical and Materials Science, National Formosa University, Yunlin 632, Taiwan ' Department of Electronic Engineering, National Formosa University, Yunlin 632, Taiwan ' Department of Electronic Engineering, National Formosa University, Yunlin 632, Taiwan ' Department of Electronic Engineering, National Formosa University, Yunlin 632, Taiwan

Abstract: 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.

Keywords: nanocrystalline TiO2; photoelectrodes; dye-sensitised solar cells; DSSC; nanotechnology; gold nanoparticles; ITO glass substrate; indium tin oxide; titanium dioxide; titania.

DOI: 10.1504/IJNT.2014.065134

International Journal of Nanotechnology, 2014 Vol.11 No.12, pp.1081 - 1087

Published online: 14 Oct 2014 *

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