Synthesis of Spirobifluorene-alt-Carbazole Copolymers with Oxadiazole Pendants and their Thermal, Electrochemical, and Photoluminescent Properties

摘要

Two new carbazole derivatives with the oxadiazole moiety substituted at the 9 position of carbazole have been facilely synthesized by an aromatic nucleophilic substitution reaction of arylamine and fluoroarenes. Alternating copolymers with spirobifluorene were then prepared by a Suzuki coupling reaction. Spirobifluorene units together with the bulky oxadiazole pendant significantly enhance the morphological stability of the copolymers. An increased pi-electron delocalization in P2 with 2,7-coupling of carbazole results in a decrease of absorption and phosphorescence emission energies as compared to P1 with 3,6-coupling of the carbazole. The bandgaps and energy levels of the polymers can be tuned by different coupling positions between carbazole and the spirobifluorene moieties.