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

Abstract

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.