| Summary: | 碩士 === 國立臺灣師範大學 === 化學系 === 97 === A series of 2,2'-bipyridine derivatives, incorporating 2- or 3-substituted carbazole, or fluorene unit, have been synthesized via Wittig-Horner reaction and Suzuki coupling. These compounds have been successfully used as ligands for Grätzel-type ruthenium dyes. The metal-to-ligand charge-transfer bands in these complexes appeared in the range of 530~550 nm. A prominent red shift of the MLCT band was observed as an olefinic entity was inserted between the 2,2'-bipyridine and the carbazole or fluorene unit to increase the effective conjugation length. Dye-sensitized solar cells based on these sensitizers exhibited good performance. Among them, Ru-vinyl-fluorene-based cell had the best performance ：η (power conversion efficiency), 4.90%；VOC (open-circuit voltage), 0.63 V；JSC (short-circuit current), 11.14 mA/cm2；FF (fill factor), 0.70. The conversion efficiency reaches ~69% of the standard device (η=7.11%) based on N719 (cis-bis(isothiocyanato)bis(2,2'-bipyridyl-4,4'-dicarboxylato)-ruthenium (II) bis-tetrabutylammonium) fabricated and measured under similar condition. The more effective light-harvesting and higher dye density on TiO2 may be the main reasons for better efficiency of Ru-vinyl-fluorene-based cell.
|
|---|
