Triblock‐Terpolymer‐Directed Self‐Assembly of Mesoporous TiO₂: High‐Performance Photoanodes for Solid‐State Dye‐Sensitized Solar Cells

Abstract A new self‐assembly platform for the fast and straightforward synthesis of bicontinuous, mesoporous TiO₂ films is presented, based on the triblock terpolymer poly(isoprene‐b‐styrene‐b‐ethylene oxide). This new materials route allows the co‐assembly of the metal oxide as a fully interconnected minority phase, which results in a highly porous photoanode with strong advantages over the state‐of‐the‐art nanoparticle‐based photoanodes employed in solid‐state dye‐sensitized solar cells. Devices fabricated through this triblock terpolymer route exhibit a high availability of sub‐bandgap states distributed in a narrow and low enough energy band, which maximizes photoinduced charge generation from a state‐of‐the‐art organic dye, C220. As a consequence, the co‐assembled mesoporous metal oxide system outperformed the conventional nanoparticle‐based electrodes fabricated and tested under the same conditions, exhibiting solar power‐conversion efficiencies of over 5%.