Noble metal nanoparticles

Noble metal nanoparticles noble metal (NM) nanoparticle in general and their gold and silver analogs in particular are attracting huge interest from the scientific community owing to their fabulous properties and diversity of applications. Mankind has been fascinated by gold and silver gold and silver since prehistoric times, and applications of their nanoparticles have attracted attention for millennia, although understanding phenomena at the nanoscale is very recent. Nanoscale analogs are being explored due to their unusual functional attributes quite unlike the bulk. As research in this area moves forward, scientists are discovering novel application possibilities. Tunability of properties by varying size, shape, composition, or local environment presents them with unusual capabilities. By manipulating the chemical composition of the materials at the nanoscale, their electrical, chemical, optical, and other properties can be manipulated precisely. In this chapter, an overview of their history, diversity, strategies of synthesis, and optical properties is presented. The specialized methods employed for synthesis of anisotropic nanosystems are also discussed. Approaches to modulate the properties of these systems postsynthetically either through chemical reactions or by the formation of superstructures via assembly are also covered. Methodologies for fabricating functionalized nanomaterials are also discussed. Various proposed applications of such materials are pointed out. A glimpse into a newly emerging category of noble metal nanosystems called quantum clusters is also given.