Fabrication of Silver Nanoparticle-Embedded Polymer Promoted by Combined Photochemical Properties of a 2,7-Diaminofluorene Derivative Dye

A one step method for the fabrication of silver nanoparticle-embedded polymer is detailed from the mechanistic aspects to the structural analysis of the material. A 2,7-diaminofluorene derivative is employed both as a photoreductant agent of silver precursors and as a free radical photoinitiator to produce silver nanoparticles in a poly(ethylene glycol) matrix at the same time. Each photophysical mechanism is separately investigated and quantified by steady state and time-resolved spectroscopy. The analysis confirms the key role the dye radical cation in the photopolymerization. Moreover, the addition of an amine co-initiator induces a clear acceleration of the photopolymerization rate and leads to a new distinctive mechanism. As a consequence, the morphology of the resultant silver nanocomposite exhibits different size distributions characterized by transmission electron microscopy. This structural observation was also correlated by an unexpected metal-enhancement fluorescence process arising from residual dyes entrapped in the metal-polymer.