SYNTHESIS AND LUMINESCENT PROPERTIES OF FLUORENE BENZOTHIADIAZOLES-ANILINE COPOLYMERS

Narrow band-gap ( NBG) units DPABT and TPABT were incorporated into polyfluorene backbones by polycondensation, respectively. The luminescent properties of two series of copolymers PF-DPABT and PF-TPBAT were investigated comparatively.,The typical emission of NBG units increased with increasing their content in the copolymers, because to the efficient energy transfer from the fluorene segment to the NBG unit occurred. The saturated red emission of PF-DPABT was peaked at 650 - 680 rim, while the orange-red emission of PF-TPABT was peaked at 590 - 610 nm. The EL emission was exclusively from the NBG unit, even if the NBG content in the copolymers wits as low its 1 mol % which implied the energy transfer was more efficient during the EL process. The highest external quantum efficiencies were 1.3 % for the device of PF-DPABT-1 and 2.0 % for the PF-TPABT-1, respectively, with the device configuration of ITO/PEDOT : PSS/polymer/Ba/AI I indicating that it was a kind of promising candidate of the red light-emitting materials.