An Unconventional Route to High-Efficiency Dye-Sensitized Solar Cells via Embedding Graphitic Thin Films into TiO2 Nanoparticle Photoanode

Graphitic thin films embedded with highly dispersed titanium dioxide (TiO2) 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 TiO2 dots embedded in carbon matrix were fabricated via UV-stabilization of polystyrene-block-poly(4-vinylpyridine) films containing TiO2 precursors followed by direct carbonization. For dye-sensitized TiO2 based solar cells containing carbon/TiO2 thin layers at both sides of pristine TiO2 layer, an increase of 40.6% in overall power conversion efficiency was achieved compared with neat TiO2-based DSSCs. Such a remarkably improved cell efficiency was ascribed to the superior electron conductivity and extended electron lifetime elucidated by cyclic voltamrnetry and impedance spectroscopy.