Preparation Of Wideband TiO₂ And Its Application In Tandem DSSC

Dye sensitized solar cells ?DSSCs? have received considerable attention as a cost-effective technology for photon-to-electron energy conversion. However, the utilization of longer wavelength sunlight is limited in traditional DSSC to a large degree. In this study, we incorporated Au NRs@SiO₂ with TiO₂ and designed tandem structure DSSC for expanded light harvesting.An effective strategy is to incorporate Au NRs@SiO₂ into TiO₂. As well-known, titania is one of the most important semiconductors and has been extensively studied for a variety of applications ranging from photocatalysis, photovoltaics to biological sciences by virtue of its low toxicity, biological compatibility, chemical and thermal stability, resistance to pho1ocorrosion, and relative abundance. However, the photocatalytic activity of titania is greatly limited to the ultraviolet region. The incorporation of Au NRs@SiO₂ into TiO₂, DSSC photoelectrodes has afforded enhanced performance through amplification of light absorption of the dye sensitizer and localized surface plasmon resonance ?LSPR?. The optimal properties were obtained in the 2.0 wt% Au NRs doped TiO₂.Another way toward improved power conversion efficiency is the utilization of tandem structure solar cell. Tandem-structured dye sensitized solar cells have been investigated to expand the photo-response into the near-IR region by introducing near-IR-responsive DSSCs as a bottom cell. TiC>2 sensitized with a red dye and the lower compartment was made of black dye-sensitized TiO₂ for the corresponding absorption of the shorter and longer wavelength regions of sunlight.In this thesis, we combined two methodology for improvement in light harvesting. The efficiency of tandem DSSCs increased from 9.02% to 10.71% upon the incorporation of 2.0% Au NRs@SiO₂.