Edge-nitrogenated graphene nanoplatelets as high-efficiency counter electrodes for dye-sensitized solar cells.
Edge-nitrogenated graphene nanoplatelets (ENGNPs) are prepared by a simple and eco-friendly mechanochemical pin-grinding process using flake graphite as the precursor in the presence of nitrogen and investigated as the counter electrodes of dye-sensitized solar cells (DSCs). SEM images and nitrogen adsorption analysis indicate an effective and spontaneous delamination of the pristine graphite into small graphene nanoplatelets by a mechanochemical pin-grinding process. The mechanochemical cracking of the graphitic C-C bond generates activated carbon sites that react directly with nitrogen at the broken edges. The resultant ENGNPs are deposited on a fluorine-doped tin oxide (FTO) substrate by spray coating, and their electrocatalytic activities are investigated systemically in the I(-)/I3(-) redox electrolyte. Electrochemical measurements show that the ENGNP electrode possesses excellent electrocatalytic activity for the redox reaction of I(-)/I3(-) as evidenced by the low charge-transfer resistance at the interface of the electrode and electrolyte. Under 100 mW cm(-2) illumination, the DSC with the optimized ENGNP counter electrode achieves a conversion efficiency of 7.69%, which is comparable to that of the device with Pt counter electrode.
School of New Energy, Bohai University, Jinzhou 121013, China. wgqiang@bhu.edu.cn.
Guiqiang
G
Wang
School of Chemical Engineering, Shandong University of Technology, Zibo 255049, China.
Juan
J
Zhang
School of New Energy, Bohai University, Jinzhou 121013, China. wgqiang@bhu.edu.cn.
Shuo
S
Hou
School of New Energy, Bohai University, Jinzhou 121013, China. wgqiang@bhu.edu.cn.
Wei
W
Zhang
School of Chemical Engineering, Shandong University of Technology, Zibo 255049, China.
Zengdian
Z
Zhao