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.

Nanomaterials, such as metal or semiconductor nanoparticles and nanorods, exhibit similar dimensions to those of biomolecules, such as proteins (enzymes, antigens, antibodies) or DNA. The integration of nanoparticles, which exhibit unique electronic, photonic, and catalytic properties, with biomaterials, which display unique recognition, catalytic, and inhibition properties, yields novel hybrid nanobiomaterials of synergetic properties and functions. This review describes recent advances in the synthesis of biomolecule-nanoparticle/nanorod hybrid systems and the application of such assemblies in the generation of 2D and 3D ordered structures in solutions and on surfaces. Particular emphasis is directed to the use of biomolecule-nanoparticle (metallic or semiconductive) assemblies for bioanalytical applications and for the fabrication of bioelectronic devices.

Integrated Nanoparticle–Biomolecule Hybrid Systems: Synthesis, Properties, and Applications

Advances in the development of novel cobalt Fischer-Tropsch catalysts for synthesis of long-chain hydrocarbons and clean fuels.

Structure and nanostructure in ionic liquids.

Titanium oxide thin film could be prepared from (NH4)2TiF6 aqueous solution with addition of boric acid by Liquid Phase Deposition (LPD) process. The aspect and chemical composition of the deposited films were different according to the concentration range of (NH4)2TiF6 and H3BO3 in the treatment solution. The deposition rate of transparent TiO2 film increased with increasing concentration of added H3BO3.

Titanium(IV)Oxide Thin Films Prepared from Aqueous Solution

Preparation and characterization of polymer thin films containing silver and silver sulfide nanoparticles

Luminescent properties of the Eu(dinic) complex, where dinic is dinicotinic acid, were examined in the presence of silver nanoparticles in N,N-dimethylformamide. The formation of particle aggregates was observed upon mixing the particle solution with the complex solution, in which the complexes behaved like linker molecules. Luminescent intensity of the complexes was enhanced in the presence of silver nanoparticles, but at only a limited particle concentration region. The observed particle concentration dependences of the luminescent intensity were regarded as the result of a delicate balance between an enhancing and a quenching effect of the silver nanoparticles. In addition to the change in intensity, silver nanoparticles also affected the asymmetric ratio (or monochromaticity) of the europium luminescence. These changes in the luminescent properties of the complex were discussed in terms of the effects of particle aggregates and consequent modifications of the local electromagnetic field, refractive in...

Enhancing and Quenching Functions of Silver Nanoparticles on the Luminescent Properties of Europium Complex in the Solution Phase

Titanium oxide powder and thin films were prepared from an (NH4)2TiF6 aqueous solution upon addition of boric acid in a process denoted as liquid phase deposition (LPD). In this process, titanium oxide powder and films were formed by the chemical equilibrium reaction between titanium fluoro-complex ions and metal oxide in the aqueous solution. The prepared powder and deposited films showed some features which differed from titanium oxide prepared from titanium alkoxide. The prepared powder and the deposited films included anatase (TiO2) and showed photocatalytic activity without prior calcination. The decomposition rate of CH3CHO reached a maximum when the powder or films were calcined at 300 °C. The LPD process enabled a uniform layer of TiO2 film to form homogeneously on the entire surface of glass wool. The prepared TiO2 contained fluorine and nitrogen. The amount of these impurities was reduced upon calcination.

Shigehito Deki

Papers

Titanium(IV)Oxide Thin Films Prepared from Aqueous Solution

Preparation and characterization of polymer thin films containing silver and silver sulfide nanoparticles

Enhancing and Quenching Functions of Silver Nanoparticles on the Luminescent Properties of Europium Complex in the Solution Phase

Photocatalytic activity of titanium oxide prepared by liquid phase deposition (LPD)

Strong Ultra‐Broadband Near‐Infrared Photoluminescence from Bismuth‐Embedded Zeolites and Their Derivatives