Effect of nanocrystalline TiO<inf>2</inf> scattering layer on the photoelectrode of dye-sensitized solar cells

Abstract

The study is to investigate that the effects of nanocrystalline TiO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> scattering layer on the photoelectrode of the dye-sensitized solar cells (DSSCs). In the analysis of field emission scanning electron microscopy (FE-SEM), TiO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> thin films prepared by electrophoresis deposition (EPD) have the porous nanocrystalline structure. The analysis of UV-Vis spectrophotometer indicates that the absorption wavelength of electrode with scattering layer can be obviously promoted from ultraviolet to visible light. In the analysis of electrochemical impedance spectroscopy (EIS), the value of T <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">eff</inf> (lifetime of an electron in TiO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> ) increases from 0.0395 to 0.0515 and R <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</inf> (charge transfer resistance related to recombination of electrons) decreases from 32 □ to 20.9 □ while TiO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> scattering layer added in photoelectrode. Form the results of I-V characteristic, the conversion efficiency of dye-sensitized solar cell with scattering layer is obviously higher than that without scattering layer. These results indicate that added scattering layer in photoelectrode can increase the path length of the incident light in the nanocrystalline TiO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> photoelectrode, and has great help for the increase on the conversion efficiency of DSSCs.