[60]Fulleropyrrolidines Bearing pi-Conjugated Moiety for Polymer Solar Cells: Contribution of the Chromophoric Substituent on C-60 to the Photocurrent

作者：Saravanan Chinnusamy; Liu Che Liang; Chang Yi Min; Lu Jan De; Hsieh Yen Ju; Rwei Syang Peng; Wang Leeyih^*

来源：ACS Applied Materials & Interfaces, 2012, 4(11): 6133-6141.

DOI：10.1021/am301773t

• fulleropyrrolidines
• C-60
• electron acceptor
• polymer solar cells
• morphology
• thermal stability

Two fullerene-terthiophene dyads without heicyl chains (3T-C-60) and with hexyl chains (3TH-C-60) on the terthiophene substituent are synthesized by 1,3-dipolar cycloaddition of corresponding azomethine ylides to C-60. The cyclic voltammetry studies indicate no apparent electronic communication between the terthiophene pendent group and the fulleropyrrolidine core in the ground state. However, a significant florescence quenching is observed for 3T-C-60 and 3TH-C-60, compared to their fluorescent terthiophene (3T) and 3TH precursors, respectively, suggesting the occurrence of strong intramolecular electron/energy transfers in the photo-excited state. Furthermore, these new fulleropyrrolidine derivatives are applied as electron acceptors to fabricate poly(3-hexylthiophene) (P3HT) based bulk heterojunction solar cells. The incident photon-to-current efficiency (IPCE) value of the P3HT/3T-C-60 device is significantly higher than that of the P3HT/PCBM cell in wavelengths of 350-420 nm. This finding provides direct evidence for the contribution of 3T excitons to the photocurrent. Replacing 3T-C-60 with 3TH-C-60 effectively improves the morphology of the photoactive layer and widens the window of optimal D/A ratios, raising the power conversion efficiency (PCE) from 2.14% to 2.54%. Importantly, these devices exhibit superior stability of PCE against high-temperature aging.

• 出版日期2012-11