Novel oligomers based on fluorene and 2,4-difluorobenzene: Correlation between the structures and optical properties

The correlation between the structures and optical properties of novel oligomers based on fluorene and 2,4-difluorobenzene is analyzed. The fine difference in the photoelectric properties of fluorene-containing oligomers with branched structures were also investigated. The synthesis of fluorene oligomers was implied by the grafting of different substituents with specific functions on parent skeletons of fluorene. The photophysical characteristics of the oligomers were investigated by PL and ultraviolet-visible absorption in both dilute THF solutions and thin films. To evaluate the difference between the photophysical properties of oligomers in terms of light-emitting ability, APQEs were determined with films in an integrated sphere at room temperature. Y-shaped fluorene-based oligomer was designed and synthesized on the basis of parent oligomers. It was found that the optical properties of the oligomers could be strongly correlated with the molecular frameworks.