Gold Nanoparticles

Abstract

Gold nanoparticles (GNPs) have been the most extensively studied colloidal systems in the area of nanoscience and nanotechnology owing to their fascinating physical and chemical properties. Nanoscience and nanotechnology are often inseparable from advances in GNPs. Diversity in the modes of preparation, unique properties, unusual stability in comparison to related materials make GNPs ideal for a vast array of applications in chemistry, biology, engineering, and medicine. This article gives an overview of the fascinating area of GNPs. The rich history of GNPs is briefly reviewed in the beginning of the article followed by a concise description of various pioneering synthetic strategies and their properties. An overview of novel anisotropic gold nanostructures is described in the subsequent section. Because of the importance of assembled nanostructures in tuning the collective properties of nanomaterials, assemblies of diverse GNPs are briefly described. Furthermore, a few interesting aspects of supported GNPs have also been outlined. Toward the end of the article, we have highlighted important applications of GNPs and have given a special mention of a new category of ultra‐small materials of gold known as atomically precise clusters. The article ends with the new directions of GNPs and outlines the prospects of future applications.

New Routes for Multicomponent Atomically Precise Metal Nanoclusters

“…22,50−53 To understand the origin of optical and electronic properties of NCs, the substitution of metal atoms by another element is worthwhile. For example, the emission intensity of rod-like [Au 25 (PPh 3 ) 10 (SR) 5 Cl 2 ] 2+ can be enhanced 200-fold by substituting 13 Au atoms with Ag. 54 The doped NC, [Ag 13 Au 12 (PPh 3 ) 10 (SR) 5 Cl 2 ] 2+ , having the same structure and nuclearity exhibits 40% photoluminescence quantum yield.…”

“…For example, the emission intensity of rod-like [Au 25 (PPh 3 ) 10 (SR) 5 Cl 2 ] 2+ can be enhanced 200-fold by substituting 13 Au atoms with Ag. 54 The doped NC, [Ag 13 Au 12 (PPh 3 ) 10 (SR) 5 Cl 2 ] 2+ , having the same structure and nuclearity exhibits 40% photoluminescence quantum yield. An interesting change in the UV−vis spectrum of Au 25 (SR) 18 was seen after single Pd/Pt doping.…”

“…There is a rich and fascinating history for metals and their alloys. − Alloys have been known from ancient times; bronze (90% Cu and 10% Sn) was the first to be invented circa BC 3500. Nanoscience has provided a new direction to the subject of metals and their alloys. − The famous Lycurgus cup known since the 4th century AD is one of the earliest known applications of nanotechnology . It is found to be composed of nanoparticles of Ag, Au, and Cu of 50–100 nm in size, dispersed in a glass matrix .…”