Organic sensitizers containing julolidine moiety for dye-sensitized solar cells.
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.
Kim
Dong Wook
DW
Advanced Materials Division, Korea Research Institute of Chemical Technology, Daejeon 305-600, Korea.
Choi
Jin Joo
JJ
Kang
Man Ku
MK
Kang
Yongku
Y
Lee
Changjin
C