title: [60]Fulleropyrrolidines bearing π-conjugated moiety for polymer solar cells: contribution of the chromophoric substituent on C₆₀ to the photocurrent.
abstract: Two fullerene-terthiophene dyads without hexyl chains (3T-C₆₀) and with hexyl chains (3TH-C₆₀) on the terthiophene substituent are synthesized by 1,3-dipolar cycloaddition of corresponding azomethine ylides to C₆₀. 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-C₆₀ and 3TH-C₆₀, compared to their fluorescent terthiophene (3T) and 3TH precursors, respectively, suggesting the occurrence of strong intramolecular electron/energy transfers in the photoexcited 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-C₆₀ 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-C₆₀ with 3TH-C₆₀ 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.
authors.affiliation: Centre for Condensed Matter Sciences, National Taiwan University, Taipei, Taiwan.
authors.forename: Chinnusamy
authors.initials: C
authors.lastname: Saravanan
authors.forename: Che-Liang
authors.initials: CL
authors.lastname: Liu
authors.forename: Yi-Min
authors.initials: YM
authors.lastname: Chang
authors.forename: Jan-De
authors.initials: JD
authors.lastname: Lu
authors.forename: Yen-Ju
authors.initials: YJ
authors.lastname: Hsieh
authors.forename: Syang-Peng
authors.initials: SP
authors.lastname: Rwei
authors.forename: Leeyih
authors.initials: L
authors.lastname: Wang
mesh_terms: D011211:Electric Power Supplies; D004579:Electron Transport; D004867:Equipment Design; D019544:Equipment Failure Analysis; D037741:Fullerenes / Q000737:chemistry* / Q000528:radiation effects; D008027:Light; D016566:Organoselenium Compounds / Q000737:chemistry*; D011759:Pyrrolidines / Q000737:chemistry* / Q000528:radiation effects; D012993:Solar Energy
chemical_list: D037741:Fullerenes; D016566:Organoselenium Compounds; D011759:Pyrrolidines; C526212:poly(3-hexyl)selenophene; C069837:fullerene C60