Synthesis of an Efficient Counter Electrode Material for Dye-Sensitized Solar Cells by Pyrolysis of Melamine and Graphene Oxide.

An efficient counter electrode material for dye sensitized solar cells (DSSCs) was synthesized by pyrolysis of melamine and graphene oxide. The synthesized samples were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy and scanning electrode microscopy, which show that nitrogen doped reduced graphene oxide (NRGO) was obtained by this synthesis method. In the synthesized NRGO, graphitic structure was kept and the nitrogen was existence as pyrrolic, pyridinic, graphitic, and oxidized nitrogen species in the samples. After deposited as counter electrode films for DSSCs, it shows lower charge-transfer resistance at the electrode/electrolyte interface and higher electrocatalytic activity towards reduction of triiodide (I₃) than that of reduced graphene oxide (RGO) prepared also by this method without adding melamine. Consequently, the DSSCs based on NRGO counter electrodes achieve an energy conversion efficiency of 4.60%, which is higher than that of RGO counter electrode (2.35%). Although the photovoltaic performance of NRGO counter electrode was lower than that of Pt counter electrode (5.70%), it is still a promising counter electrode to replace noble metal Pt due to its low cost and simple synthesis process.