Synthesis and optical properties of poly(thiophene-fluorene) copolymers with benzothiazole moiety

Poly[9,9-dihexylfluorene-co-(benzothiazol-2-yl)thiophene-co-9,9′-spirobifluorene] (PF_xB_yS_z) were synthesized by palladium-catalyzed Suzuki coupling reaction. PF_xB_yS_z were characterized by FT-IR, elemental analysis, and ¹H NMR. All the copolymers showed decomposition temperatures above 400 °C and glass transition points above 180 °C, suggesting that these materials had excellent thermal stability. As the benzothiazolylthiophene content in copolymers was increased, the band gaps of copolymers decreased. All the copolymers exhibited fluorescence peaks in the visible region, and the energy transfer from fluorene to benzothiazolylthiophene units were observed.