Silica-Conjugated Polymer Hybrid Fluorescent Nanoparticles: Preparation by Surface-Initiated Polymerization and Spectroscopic Studies

Organic/inorganic hybrid nanoscale materials possess fascinating optical, electronic, magnetic, and catalytic properties that are promising for a variety of practical applications. Such properties can be dramatically affected by the hierarchical structure and molecular organization in the nanomaterials. Herein, we employed surface-initiated Kumada catalyst-transfer polymerization to prepare hybrid materials consisting of shells of conjugated polymers (CPs)-polythiophene or poly(p-phenylene)-and their block copolymers covalently attached to the surface of silica nanoparticles. Because of the controlled chain-growth mechanism of surface-initiated polymerization, we obtained structurally well-defined CP blocks in the diblock copolymer shells, which produced distinct spectroscopic properties related to the intraparticle excitation energy transfer between the nanoscale polymer shell components, as well as the formation of interfacial exciplex states. The spectroscopic phenomena were further understood via time-resolved transient absorption spectroscopy studies. Overall, the surface-initiated polymerization provided an efficient tool to prepare structurally defined and highly stable organic polymer shell-inorganic core nanoparticles with tunable spectroscopic characteristics not achievable from corresponding single-component systems.