Dye-sensitized solar cells based on hierarchically structured porous TiO 2 filled with nanoparticles

A new morphology of TiO 2 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) TiO 2 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 TiO 2 filled with nanoparticles have been demonstrated. DSCs based on a special TiO 2 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 TiO 2 photoanode with high dye adsorption due to its ordered and open structures, and also its light scattering and charge collection efficiency.