Tunable synthesis of single-crystalline-like TiO2 mesocrystals and their application as effective scattering layer in dye-sensitized solar cells

Single-crystalline-like TiO2 mesocrystals (TMCs) with spherical and spindle-like shapes were selectively prepared in acetic acid system using benzoic acid as structural directing regent. It was found that the intermediate butyl-benzoic acid could interval the oriented assembly of the primary nanoparticles as porogen and shape regulator, which results in spherical TMCs with greater pore size distribution compared with the spindle-like TMCs. When used as scattering layer in dye sensitized solar cells (DSSCs), the spherical TMCs with long-range ordered stacking pattern results in characteristic photonic reflection, which enhances the scattering effect of the photoanode and leads to a high short circuit current density of 16.6 mA cm(-2). Therefore, Cell-spherical TMCs demonstrated a high power conversion efficiencies of 8.10%, indicating substantial improvements compared with Cell-spindle-like TMCs (7.58%) and Cell-nanoparticle (6.59%).