Honeycomb‐Like Organized TiO 2 Photoanodes with Dual Pores for Solid‐State Dye‐Sensitized Solar Cells

A solid‐state dye‐sensitized solar cell (ssDSSC) with 7.4% efficiency at 100 mW/cm 2 is reported. This efficiency is one of the highest observed for N719 dye. High performance is achieved via a honeycomb‐like, organized mesoporous TiO 2 photoanode with dual pores, high porosity, good interconnectivity, and excellent light scattering properties. The TiO 2 photoanodes are prepared without any TiCl 4 treatment via a one‐step, direct self‐assembly of hydrophilically preformed TiO 2 nanocrystals and poly(vinyl chloride)‐ g ‐poly(oxyethylene methacrylate) (PVC‐ g ‐POEM) graft copolymer as a titania source and a structure‐directing agent, respectively. Upon controlling the secondary forces between the polymer/TiO 2 hybrid and the solvent by varying the amounts of HCl/H 2 O mixture or toluene, honeycomb‐like structures are generated to improve light scattering properties. Such multifunctional nanostructures with dual pores provide good pore‐filling of solid polymer electrolyte with large volume, enhanced light harvesting and reduced charge recombination, as confirmed by reflectance spectroscopy, incident photon‐to‐electron conversion efficiency (IPCE), and electrochemical impedance spectroscopy (EIS) analysis.