Photogenerating Silver Nanoparticles and Polymer Nanocomposites by Direct Activation in the Near Infrared

This work reports on an improvement of the photochemically assisted synthesis of silver nanoparticles by direct photoreduction of AgNO3 with a laser source emitting in the near infrared range (NIR). For this, polymethine dyes were used as the photoactive agents. Both the effects of central chain structure and activation intensity were investigated. The reduction kinetics was followed up by UV-Vis spectroscopy, and the particles size was evaluated by transmission electron microscopy. The results showed that light intensity affects both the average size and size distribution of Ag nanoparticles generated through this process. The particles can also be generated in situ in a photopolymerizable formulation so that metal/polymer nanocomposites become available through a one-step photoassisted process on the basis of NIR activation. The process described herein is very fast (seconds to a few minutes), and it readily lends itself to automatization for mass production of micro-optical elements implemented directly onto integrated NIR sources.