title: Organic sensitizers containing julolidine moiety for dye-sensitized solar cells.
abstract: We prepared organic sensitizers (S1 and S2) containing julolidine moiety as a donor, phenyl or phenylene thiophene units as a conjugation bridge, and cyano acetic acid as an acceptor for dye sensitized solar cells. S1 exhibited two absorption maxima at 441 nm (epsilon = 26,200) and 317 nm (epsilon = 15,500) due to the pi-pi transition of the dye molecule. S2 dyes with an additional thiophene unit showed the absorption maximum extended by 18 nm. DSSCs based on S1 dye achieved 2.66% of power conversion efficiency with 8.3 mA cm(-2) of short circuit current, 576 mV of open circuit voltage, and 0.56 of fill factor. DSSCs using S2 dye with a longer conjugation attained only 1.48% of power conversion efficiency. The 0.21 V lower driving force for regeneration of the S2 dye compared to the Si dye is one of the reasons for low conversion efficiency of the S2 dye.
authors.affiliation: Advanced Materials Division, Korea Research Institute of Chemical Technology, Daejeon 305-600, Korea.
authors.forename: Dong Wook
authors.initials: DW
authors.lastname: Kim
authors.forename: Jin Joo
authors.initials: JJ
authors.lastname: Choi
authors.forename: Man Ku
authors.initials: MK
authors.lastname: Kang
authors.forename: Yongku
authors.initials: Y
authors.lastname: Kang
authors.forename: Changjin
authors.initials: C
authors.lastname: Lee