Photochemical fabrication of silver nanostructures at the solid―liquid interface using a recyclable photosensitized reduction process

Photochemical synthesis of metal nanostructures through photosensitized reduction of metal sources is a powerful method in a wide variety of environments, because light can selectively promote the desired reaction without damaging the surrounding environment. A drawback of the method is that most organic photosensitizers are disposable and consumed during the photochemical reactions and as a consequence a much larger amount of photosensitizer than that of the metal source is usually required, and therefore, the photosensitized reduction method is wasteful in terms of the sensitizer. In the present work, we propose a new photochemical synthetic method using a recyclable photosensitizer and applied it to fabricate Ag nanostructures at the solid-liquid interface. The photosensitized reduction of Ag ion at the solid-liquid interface resulted in the formation of unique Ag nanostructures (nanowires or plates) without the use of templates or stabilizing agents. The relation between the morphology and several external contributing factors, such as solvent polarity and interaction between the substrate and crystal phase, was discussed.