Synthesis, characterization and properties of fluorenyl phenyl, based conjugated organic materials

Fluorene and its derivatives are important conjugated organic materials for electronic devices. Their oligomers and polymers are the promising blue light-emitting materials with extremely high photoluminescence, quantum yields, and thermal and oxidative stability. The substitutes and stereo of the conjugated compounds play an important role on their electronic properties. In this paper, two kinds of fluorenyl-phenyl oligormers with thiomethyl group such as 2, 7-bis-(4-methylsulfanyl-phenyl)-9, 9-dihexyl- fluorene(a) and 2, 7-bis-(2, 6-dimethyl-4-methylsulfanyl-phenyl)-9, 9-dihexyl-fluorene(b) were synthesized via the double Suzuki-Miyaura cross-coupling in the presence of palladium catalysts. The theory and property investigation show that compound a is more conjugated than compound b. The maximum absorption and fluorescence emission wavelength of compound a are at 351 and 410 nm, respectively. In the contrast, the corresponding absorption and emission of compound b are blue-shift of 38 and 43 nm, respectively. In addition, the synthesized fluorenyl-phenyl oligormers a and b have high fluorescence quantum yields of 59% and 65%, respectively. The superior properties of the fluorenyl-phenyl oligormers make these compounds be candidates of organic light-emitting materials.