A low-cost bio-inspired integrated carbon counter electrode for high conversion efficiency dye-sensitized solar cells

A novel bio-inspired Pt- and FTO-free integrated pure carbon counter electrode (CE) for dye-sensitized solar cells (DSSCs) has been designed and fabricated using a porous carbon sheet as a conducting substrate and ordered mesoporous carbon (OMC) as the catalytic layer. A rigid, crustose lichen-like, integrated carbon-carbon composite architecture with a catalytic layer rooted in a porous conducting substrate was formed by a process of polymer precursor spin coating, infiltration and pyrolysis. The integrated pure carbon CE shows very low series resistance (R-s), owing to the high conductivity of the carbon sheet (sheet resistance of 488 m Omega square(-1)) and low charge-transfer resistance (R-ct), due to the large specific surface area of the OMC layer that is accessible to the redox couple. The values of R-s and R-ct are much lower than those of a platinized fluorine-doped thin oxide glass (Pt/FTO) electrode. Cells with this CE show high solar-to-electricity conversion efficiencies (8.11%), comparable to that of Pt/FTO based devices (8.16%).