Pure blue-light emissive poly(oligofluorenes) with bifunctional poss in the main chain.

Emission of conjugated polymers is known to undergo bathochromic shift from solution to film formation due to π-π stacking in the solid state. In this report, a series of pearl-necklace-like hybrid polymers is designed via the hydrosilylation condensation between bifunctional polyhedral oligomeric silsesquioxanes (B-POSS) and oligofluorene segments. Optoelectronic analyses unequivocally show that the presence of these interconnecting B-POSS can effectively reduce red-shift in photoluminescence and electroluminescence during film formation. These hybrid poly(oligofluorenes) display stable blue emission with high color purity. Thermal analyses also indicate that they are vitrified polymers with high glass transition temperature (up to 125 °C). We believe that this strategy can be extended to other conjugated systems to control color purity in electroactive materials and holds promise as new emissive materials for various applications.