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

Two NIR BODIPY dyes T′ 2 P 2 A and T′′ 2 P 2 A were synthesized and used as photosensitizers in dye sensitized solar cells (DSSCs). T′ 2 P 2 A and T′′ 2 P 2 A 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′ 2 P 2 A based DSSC. Furthermore, based on the complementary absorption spectra of TP 2 A and T′ 2 P 2 A, even more efficient co-sensitized DSSCs were fabricated. The DSSC based on TP 2 A + T′ 2 P 2 A shows an enhancement in the IPCE from 47% to 74% at 550 nm compared to that based on the single dye system T′ 2 P 2 A. Finally, a high PCE of 6.67% was obtained for the TP 2 A + T′ 2 P 2 A co-sensitized DSSC, which was higher than the performances of each individual dye. Two NIR BODIPY dyes T′ 2 P 2 A and T′′ 2 P 2 A were synthesized and used as photosensitizers in dye sensitized solar cells (DSSCs).