Synthesis of polyhedral oligomeric silsesquioxane-functionalized polyfluorenes: Hybrid organic–inorganic π-conjugated polymers

Polyfluorenes with appended polyhedral oligomeric silsesquioxanes (POSSs) were successfully synthesized through Ni(0)-mediated polymerization. The resulting copolymers exhibit good solubility in common organic solvents such as chloroform, chlorobenzene, etc. and good thermal stability. The PL quantum yields of the copolymers were drastically enhanced compared to PDHF because the POSS-functionalized PFs strongly suppressed intermolecular aggregation and/or thermal oxidation and crosslinking. This effective dilution effect and the higher stability of the POSS showed a deep blue emission in electroluminescent devices. LED devices with these polymers showed low turn-on voltage of near 4.0 V and brightness of 260–460 cd/m2.