Fluorene-based Statistical Copolymers

Light-emissive statistical copolymers were synthesized between 9,9'-dihexylfluorene and a mixture of meta- and para-divinylenephenylene by the Heck reaction. The copolymers were soluble in organic solvents and thermally stable. The absorption spectra of copolymers showed two peaks at 382 and 410 nm revealing the existence of both the alternating copolymers with the meta- and para-linkaged. However, the photoluminescence spectra showed the single emission peak at 482 nm of the lower energy state due to the electronic energy transfer. The highest PL quantum efficiency was observed from the copolymer with 30% of the para-linkaged. Light-emitting diodes of the copolymers and their blends sandwiched between aluminum and ITO coated glass emitted blue-light with the highest quantum efficiency of 0.1%.