Although gold is the subject of one of the most ancient themes of investigation in science, its renaissance now leads to an exponentially increasing number of publications, especially in the context of emerging nanoscience and nanotechnology with nanoparticles and self-assembled monolayers (SAMs). We will limit the present review to gold nanoparticles (AuNPs), also called gold colloids. AuNPs are the most stable metal nanoparticles, and they present fascinating aspects such as their assembly of multiple types involving materials science, the behavior of the individual particles, size-related electronic, magnetic and optical properties (quantum size effect), and their applications to catalysis and biology. Their promises are in these fields as well as in the bottom-up approach of nanotechnology, and they will be key materials and building block in the 21st century. Whereas the extraction of gold started in the 5th millennium B.C. near Varna (Bulgaria) and reached 10 tons per year in Egypt around 1200-1300 B.C. when the marvelous statue of Touthankamon was constructed, it is probable that “soluble” gold appeared around the 5th or 4th century B.C. in Egypt and China. In antiquity, materials were used in an ecological sense for both aesthetic and curative purposes. Colloidal gold was used to make ruby glass 293 Chem. Rev. 2004, 104, 293−346

Gold nanoparticles: assembly, supramolecular chemistry, quantum-size-related properties, and applications toward biology, catalysis, and nanotechnology.

The interest in nanoscale materials stems from the fact that new properties are acquired at this length scale and, equally important, that these properties * To whom correspondence should be addressed. Phone, 404-8940292; fax, 404-894-0294; e-mail, mostafa.el-sayed@ chemistry.gatech.edu. † Case Western Reserve UniversitysMillis 2258. ‡ Phone, 216-368-5918; fax, 216-368-3006; e-mail, burda@case.edu. § Georgia Institute of Technology. 1025 Chem. Rev. 2005, 105, 1025−1102

Chemistry and properties of nanocrystals of different shapes.

This review focuses on the synthesis, protection, functionalization, and application of magnetic nanoparticles, as well as the magnetic properties of nanostructured systems. Substantial progress in the size and shape control of magnetic nanoparticles has been made by developing methods such as co-precipitation, thermal decomposition and/or reduction, micelle synthesis, and hydrothermal synthesis. A major challenge still is protection against corrosion, and therefore suitable protection strategies will be emphasized, for example, surfactant/polymer coating, silica coating and carbon coating of magnetic nanoparticles or embedding them in a matrix/support. Properly protected magnetic nanoparticles can be used as building blocks for the fabrication of various functional systems, and their application in catalysis and biotechnology will be briefly reviewed. Finally, some future trends and perspectives in these research areas will be outlined.

Magnetic nanoparticles: Synthesis, protection, functionalization, and application

Nanocrystals are fundamental to modern science and technology. Mastery over the shape of a nanocrystal enables control of its properties and enhancement of its usefulness for a given application. Our aim is to present a comprehensive review of current research activities that center on the shape-controlled synthesis of metal nanocrystals. We begin with a brief introduction to nucleation and growth within the context of metal nanocrystal synthesis, followed by a discussion of the possible shapes that a metal nanocrystal might take under different conditions. We then focus on a variety of experimental parameters that have been explored to manipulate the nucleation and growth of metal nanocrystals in solution-phase syntheses in an effort to generate specific shapes. We then elaborate on these approaches by selecting examples in which there is already reasonable understanding for the observed shape control or at least the protocols have proven to be reproducible and controllable. Finally, we highlight a number of applications that have been enabled and/or enhanced by the shape-controlled synthesis of metal nanocrystals. We conclude this article with personal perspectives on the directions toward which future research in this field might take.

Shape‐Controlled Synthesis of Metal Nanocrystals: Simple Chemistry Meets Complex Physics?

Core/Shell Nanoparticles: Classes, Properties, Synthesis Mechanisms, Characterization, and Applications

Synthesis of Monodisperse Ultrapure Gallium Nitride Nanoparticles by MOCVD

An experimental study of ion-induced nucleation using a drift tube ion mobility spectrometer/mass spectrometer and a cluster-differential mobility analyzer/Faraday cup electrometer

Size- and charge-controllable polystyrene spheres for templates in the preparation of porous silica particles with tunable internal hole configurations

Single route for producing organized metallic domes, dots, and pores by colloidal templating and over-sputtering

Online measurement of the effective density of both spherical aggregated and ordered porous particles was systematically investigated using differential mobility analyzer-aerosol particle mass analyzer (DMA-APM). Effective density was determined based on the relationship between electric mobility and mass; mobility and mass were measured using DMA and APM, respectively. The particles were prepared using a spray-drying method; a colloidal suspension of silica nanoparticles was used as the precursor, and both nanoparticles and polystyrene latex (PSL) particles were used to generate the aggregated and ordered porous particles. The effective density of aggregated particles decreased from 1916.0 to 1565.2 kg/m3 when the primary particle size was increased from 6 to 100 nm. The effects of pore size and fraction, which were controlled by PSL particle concentration and size, on the effective density of ordered porous particles were also investigated. The effective density of the ordered porous particles decreased...

https://www.tandfonline.com/doi/pdf/10.1080/02786820802530524

Kikuo Okuyama

Papers

Synthesis of Monodisperse Ultrapure Gallium Nitride Nanoparticles by MOCVD

An experimental study of ion-induced nucleation using a drift tube ion mobility spectrometer/mass spectrometer and a cluster-differential mobility analyzer/Faraday cup electrometer

Size- and charge-controllable polystyrene spheres for templates in the preparation of porous silica particles with tunable internal hole configurations

Single route for producing organized metallic domes, dots, and pores by colloidal templating and over-sputtering

Measurement of the Effective Density of Both Spherical Aggregated and Ordered Porous Aerosol Particles Using Mobility- and Mass-Analyzers