A near-infrared thienyl-BODIPY co-sensitizer for high-efficiency dye-sensitized solar cells

Abstract

Two NIR BODIPY dyes T′₂P₂A and T′′₂P₂A were synthesized and used as photosensitizers in dye sensitized solar cells (DSSCs). T′₂P₂A and T′′₂P₂A were designed by incorporation of bis-thienyl vinyl and thienothiophene vinyl side-arms in the structure. This leads to a red shift in the absorption spectra leading to an enhancement in the incident photon to current conversion efficiency (IPCE). A high IPCE value of 64% at 750 nm and a power conversion efficiency (PCE) of 6.06% were observed for the T′₂P₂A based DSSC. Furthermore, based on the complementary absorption spectra of TP₂A and T′₂P₂A, even more efficient co-sensitized DSSCs were fabricated. The DSSC based on TP₂A + T′₂P₂A shows an enhancement in the IPCE from 47% to 74% at 550 nm compared to that based on the single dye system T′₂P₂A. Finally, a high PCE of 6.67% was obtained for the TP₂A + T′₂P₂A co-sensitized DSSC, which was higher than the performances of each individual dye.