Abstract
A Mo/Pt bilayered catalytic layer on a flat glass substrate was used as a counter electrode to improve the energy conversion efficiency of a dye-sensitized solar cell device with the structure of effective area of $0.45cm^2$ glass/FTO/blocking layer/$TiO_2$/N719(dye)/electrolyte/50 nm Pt/50 nm Mo/glass. For comparison, 100 nm-thick Pt and Mo counter electrodes on flat glass substrates were also prepared using the same procedure. The photovoltaic properties, such as the short circuit current density, open circuit voltage, fill factor, energy conversion efficiency, and impedance, were characterized using a solar simulator and potentiostat. The phases and microstructures of the catalytic layers were examined by X-ray diffraction and field emission electron microscopy. The measured energy conversion efficiency of the dye-sensitized solar cell devices with only Pt and Mo/Pt bilayer counter electrodes was 4.60% and 6.30%, respectively. The interface resistance at the interface between the counter electrode and electrolyte decreased when a Mo/Pt bilayer thin film was used. The new phase of $Pt_3Mo$ led to an increase in catalytic activity. This suggests that the Mo/Pt bilayered catalytic layers may provide better efficiency in the dye-sensitized solar cells than the conventional Pt layers.
