ABSTRACT
Unlike semiconductor-based nanoparticles, noble metal particles are not a recent innovation. They have been used as pigments in exotic paints and glasses for centuries, although the physics behind their optical properties have only recently become well understood. This chapter introduces one of the most widely implemented noble metal nanoparticles, gold, including a brief description of the relationship between particle size, morphology, and photophysical properties, as well as suggestions as to how to use them in varying light microscope conformations. Gold particles are probably the simplest nanomaterials to synthesize. Investigations of the interactions of light with matter have been ongoing for over three centuries, with major developments as recently as the late 1940s. While the earliest known applications of gold nanoparticle date back several centuries, direct correlations between synthesis conditions and nanoparticle geometry were not possible until many years later. Particle growth is controlled by the relative concentration of metal ions and reducing agent, temperature, and in some cases, mixing.
