Photochemistry for the Synthesis of Noble Metal Nanoparticles

The synthesis of metal nanoparticles is an interdisciplinary subject that is attracting intense research and development owing to the fundamental scientific value of nanometer-sized metal, as well as the broad range of potential applications of metal nanoparticles. Photochemistry plays an important role in various aspects of this research area. It is a unique tool for synthesizing metal nanoparticles, as well as an important technique for investigating the formation mechanism. Metal nanoparticles formation triggered by photochemical reaction is effective for investigating formation mechanisms. We succeeded in observing the formation of metal nanoparticles and clusters by using spectroscopic methods. In addition, single-molecule fluorescent spectroscopy provided important insights into the photochemical reactivity of metal clusters. This photochemical reactivity offers a promising possibility with regard to metal clusters. We developed strategies for constructing metal nanoparticles using a series of photochemical techniques. In situ photochemical synthesis is an effective method for the fabrication of metal nanoparticles, as well as composite materials. A multicolor excitation-induced photochemical reaction resulted in the reduction of metal ions with a highly negative reduction potential, recyclable photosensitization, and 3-D direct laser writing of metal nanoparticles. These new strategies will expand the possible applications of photochemistry for metal nanoparticles synthesis.