High performance dye anchored counter electrodes with a SPSQ2 sensitizer for dye sensitized solar cell applications

Abstract

High performance counter electrodes (CEs) based on dye anchoring have been developed via a low cost spray gun. Their performance was further optimized using PEDOT:PSS over the dye anchored counter electrode (DACE). Here we demonstrate DACE based devices using a near-infrared unsymmetrical squaraine sensitizer (SPSQ2) and commercially available N719 dye. The electrochemical impedance spectroscopy (EIS) results reveal that the charge transfer activity of the DACE devices shows a more optimal performance than those without DACEs. A significant increase in photoconversion efficiency was observed for the PEDOT:PSS sprayed DACE (5.75%) as the counter electrodes associated with low series resistance, low electrolyte diffusion impedance, high open circuit voltage and fill factor when compared to the simple DACE and normal counter electrode DSSCs. The enhanced efficiency could be due to the charge carriers generated in the test cells associated with SPSQ2 dye on the counter electrode and an additional PEDOT:PSS layer on the DACE.