Dye-sensitized solar cells based on low cost carbon-coated tungsten disulphide counter electrodes

• Carbon-coated WS2 films are used as the counter electrode in dye-sensitized solar cells.
• The plastic carbon-coated WS2 counter electrodes are prepared at room temperature.
• The device with carbon-coated WS2 electrode exhibits comparable performance to that of the cell with Pt electrode.

Carbon-coated tungsten disulphide (WS2) is synthesized using a simple method and characterized with X-ray diffraction, field emission scanning electron microscopy and laser Raman spectrum. The WS2-based counter electrodes for dye-sensitized solar cells (DSSCs) are prepared at low temperature. The electrochemical catalytic activity of the WS2 counter electrodes is investigated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The DSSCs assembled with carbon-coated WS2 counter electrodes show a photovoltaic conversion efficiency of 5.5%, which is comparable to that of the DSSCs based on Pt electrode (5.6%). Plastic WS2 counter electrodes are also prepared which give a photovoltaic conversion efficiency of 5.0%. Our study indicates that carbon-coated WS2 is a good candidate to replace the Pt counter electrodes in DSSCs.