Dye-sensitized solar cells based on hierarchically structured porous TiO2 filled with nanoparticles

Abstract

A new morphology of TiO₂ photoanodes for N-719 dye-sensitized solar cells (DSCs) has been developed with enhanced power conversion performance. Strategies for the synthesis of hierarchically structured three-dimensionally ordered macroporous (HS-3DOM) TiO₂ with controlled macropore sizes (ca. 85–155 nm) by using well-arrayed polymethyl methacrylate with different diameters as well as two kinds of photoanode films based on hierarchically structured porous TiO₂ filled with nanoparticles have been demonstrated. DSCs based on a special TiO₂ photoanode with a macropore size of 105 nm exhibited a current density (J_sc) of 20.6 mA cm⁻² and a high photo-to-electrical energy conversion efficiency (η) of 9.7%. This high power conversion efficiency is ascribed to the special morphology of the TiO₂ photoanode with high dye adsorption due to its ordered and open structures, and also its light scattering and charge collection efficiency.