Synthesis of platinum/reduced graphene oxide composite pastes for fabrication of cathodes in dye-sensitized solar cells with screen-printing technology

[Display omitted] •Platinum/reduced graphene oxide (Pt/rGO) composite pastes were successfully synthesized.•The annealing temperature of 450 °C was appropriate for fabrication of Pt/rGO cathodes.•Pt/rGO cathodes were fabricated with high electrochemical properties.•DSSCs fabricated from Pt/rGO cathodes demonstrated high conversion efficiencies. Platinum/reduced graphene oxide (Pt/rGO) composite materials with different mass ratios were fabricated by thermal decomposition method from H2PtCl6 and reduced graphene oxide (rGO) as precursors. The Pt/rGO composites were used for fabrication of Pt/rGO cathodes by the screen-printing method. The electrochemical properties of the fabricated cathodes were measured using cyclic voltammetry. The dye-sensitized solar cells (DSSCs) were assembled from fabricated cathodes and tested by current density–voltage (J-V) curves and electrochemical impedance spectroscopy (EIS). The results showed that the appropriate replacement amount of rGO for Pt was 20 wt%, with the efficiency of 6.42%, higher than that of commercial Pt cathode. The characterization of the appropriate Pt/rGO composite was investigated by Fourier-transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, and transmission electron microscopy. The characterization results demonstrated that Pt/rGO composite material was synthesized and the Pt nanoparticles with size of 10–30 nm were evenly distributed on the rGO sheets. These results indicated that Pt/rGO could be appropriated material to replace Pt in DSSCs in order to reduce the production cost and maintain efficiency.