High efficiency dye sensitized solar cells employing the Cr/Pt bilayered catalytic layer

摘要

In order to improve energy conversion efficiency by applying a Cr/Pt bilayer on a flat glass substrate of a counter electrode (CE), we prepared a 0.45 cm~2 dye-sensitized solar cell (DSSC) device with glass/FTO/blocking Iayer/TiO_2/N719 (dye)/electrolyte/50 nm Pt/50 nm Cr/FTO/glass. For comparison, a 100 nm-thick Pt counter electrode on a FTO substrate was also prepared using the same procedure. The photovoltaic properties, the short circuit current density, open circuit voltage, fill factor, energy conversion efficiency, and impedance, were characterized using a solar simulator and potentiostat. The phase and microstructure of the bilayer were examined by X-ray diffraction and transmission electron microscopy. The measured energy conversion efficiencies of the dye-sensitized solar cell devices with Pt only and Cr/Pt bilayer counter electrodes were 6.33% and 8.66%, respectively. The increase in the efficiency of Cr/Pt was attributed to the enhanced catalytic activated Pt layer by the compressive strain field due to the introduction of a Cr layer. This suggests that the use of a Cr/Pt bilayered catalytic layer improves the efficiency of dye-sensitized solar cells over those with a conventional Pt only layer.