High molar extinction coefficient organic sensitizers for efficient dye-sensitized solar cells

Abstract

We have designed and synthesized highly efficient organic sensitizers with a planar thienothiophene-vinylene-thienothiophene linker. Under standard global AM 1.5 solar conditions, the JK-113-sensitized cell gave a short circuit photocurrent density (Jsc) of 17.61 m A cm-2, an open-circuit voltage (VOC,) of 0.71 V, and a fill factor (FF) of 72%, corresponding to an overall conversion efficiency (η) of 9.1%. The incident monochromatic photo-to-current conversion efficiency (IPCE) of JK-113 exceeds 80% over the spectral region from 400 to 640 nm, reaching its maximum of 93% at 475 nm. The band tails off toward 770 nm, contributing to the broad spectral light harvesting. Solar-cell devices based on the sensitizer JK-113 in conjunction with a volatile electrolyte and a solvent-free ionic liquid electrolyte gave high conversion efficiencies of 9.1% and 7.9%, respectively. The JK-113-based solar cell fabricated using a solvent-free ionic liquid electrolyte showed excellent stability under light soaking at 60°C for 1000 h. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.