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.