Study of dye-sensitized solar cells by scanning electron micrograph observation and thickness optimization of porous TiO2electrodes

Abstract

In order to improve the photoenergy conversion efficiency of dye-sensitized solar cells (DSCs), it is important to optimize their porous TiO2 electrodes. This paper examines the surface and cross-sectional views of the electrodes using scanning electron micrography. Two types of samples for cross-sectional viewing were prepared by mechanically breaking the substrate and by using an Ar-ion etching beam. The former displays the surface of the TiO2 particles and the latter shows the cross-section of the TiO 2 particles. We found interesting surface and cross-sectional structures in the scattering layer containing the 400nm diameter particles, which have an angular and horned shape. The influence of TiO2 particle size and the thickness of the nanocrystalline- TiO2 electrode in DSCs using four kinds of sensitizing dyes (D149, K19, N719 and Z907) and two kinds of electrolytes (acetonitrile-based and ionic-liquid electrolytes) are discussed in regards to conversion efficiency, which this paper aims to optimize. © 2009 Seigo Ito et al.