Carbon nanotubes hybrid carbon counter electrode for high efficiency dye-sensitized solar cells

We report a solution-based method to prepare a hybrid carbon materials consisted of carbon nanotubes modified graphite/carbon black as a low-cost platinum-free counter electrode for dye-sensitized solar cell (DSSC). The effects of carbon nanotube content on the performance of counter electrode are examined. The 25 wt% carbon nanotubes in carbon counter electrode exhibit high catalytic activity for the reduction of triiodide to iodide and low charge transfer resistance at the electrolyte-electrode interface. The DSSC based on this counter electrode achieves a high power conversion efficiency of 6.94 % under 100 mW cm(-2) illumination (AM 1.5), which is comparable to 7.06 % for the DSSC with Pt counter electrode. It is expected that this low cost hybrid carbon counter electrode with simple manufacturing process would make the carbon catalyst-based monolithic DSSC more efficient in practical application.