Noble metal-free Co@N-doped carbon nanotubes as efficient counter electrode in dye-sensitized solar cells

We report the synthesis of efficient noble metal-free counter electrode materials, Co@N-doped carbon nanotubes by one-step direct pyrolysis of ZIF-67 metal-organic framework under hydrogen atmosphere. It has been demonstrated that the dye-sensitized solar cell using Co@N-doped carbon nanotubes as counter electrode exhibits the best power conversion efficiency of 8.18% than that of 7.54% using Pt counter electrode due to its excellent electrocatalytic activity towards the reduction of I−/I3−. The results indicate the enormous potential of Co@N-doped carbon nanotubes in commercialization of low cost DSSCs.