An unconventional route to high-efficiency dye-sensitized solar cells via embedding graphitic thin films into TiO ₂ nanoparticle photoanode

Graphitic thin films embedded with highly dispersed titanium dioxide (TiO ₂) nanoparticles were incorporated for the first time into the conventional dye-sensitized solar cells (DSSCs), resulting in a remarkably improved cell efficiency due to its superior electron conductivity. Massively ordered arrays of TiO ₂ dots embedded in carbon matrix were fabricated via UV-stabilization of polystyrene-block-poly(4-vinylpyridine) films containing TiO ₂ precursors followed by direct carbonization. For dye-sensitized TiO ₂ based solar cells containing carbon/TiO ₂ thin layers at both sides of pristine TiO ₂ layer, an increase of 40.6% in overall power conversion efficiency was achieved compared with neat TiO ₂-based DSSCs. Such a remarkably improved cell efficiency was ascribed to the superior electron conductivity and extended electron lifetime elucidated by cyclic voltammetry and impedance spectroscopy.