Nitrogen-doped graphene as transparent counter electrode for efficient dye-sensitized solar cells

Nitrogen-doped graphene sheets are prepared through a hydrothermal reduction of graphite oxide in the presence of ammonia and applied to fabricate the transparent counter electrode of dye-sensitized solar cells. The atomic percentage of nitrogen in doped graphene sample is about 2.5%, and the nitrogen bonds display pyridine and pyrrole-like configurations. Cyclic voltammetry studies demonstrate a much higher electrocatalytic activity toward I−/I3− redox reaction for nitrogen-doped graphene, as compared with pristine graphene. The dye-sensitized solar cell with this transparent nitrogen-doped graphene counter electrode shows conversion efficiencies of 6.12% and 5.23% corresponding to front-side and rear-side illumination, respectively. Meanwhile, the cell with a Pt counter electrode shows a conversion efficiency of 6.97% under the same experimental condition. These promising results highlight the potential application of nitrogen-doped graphene in cost-effective, transparent dye-sensitized solar cells.

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► NG sheets are prepared through a hydrothermal reduction of graphite oxide.
► The transparent NG counter electrodes of DSCs are fabricated at room temperature.
► Transparent NG electrode exhibits excellent catalytic activity for the reduction of I3−.
► The DSC with NG electrode achieves a comparable efficiency to that of the Pt-based cell.
► The efficiency of rear illumination is about 85% that of front illumination.