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?

On the Controllable Soft-Templating Approach to Mesoporous Silicates

Ordered mesoporous materials in catalysis

Gold nanorods have been receiving extensive attention owing to their extremely attractive applications in biomedical technologies, plasmon-enhanced spectroscopies, and optical and optoelectronic devices. The growth methods and plasmonic properties of Au nanorods have therefore been intensively studied. In this review, we present a comprehensive overview of the flourishing field of Au nanorods in the past five years. We will focus mainly on the approaches for the growth, shape and size tuning, functionalization, and assembly of Au nanorods, as well as the methods for the preparation of their hybrid structures. The plasmonic properties and the associated applications of Au nanorods will also be discussed in detail.

Gold nanorods and their plasmonic properties

A review of NIR dyes in cancer targeting and imaging.

Gold nanorods (NRs) have received much attention due to their size-dependent surface plasmon-related optical properties. A seed-mediated approach has recently been developed for the synthesis of Au NRs with varying length-to-diameter aspect ratios. With the introduction of silver ions in the growth solution, Au NRs of narrow size distributions can be produced in high yields. Herein we describe an approach for the continuous and selective shortening of Au NRs synthesized by the silver ion-assisted seed-mediated method through oxidation with environmentally benign oxygen at slightly elevated temperatures. UV−visible extinction measurements indicate that the longitudinal surface plasmon band of Au NRs decreases in intensity and blue-shifts as a function of the oxidation time. Transmission electron microscopy (TEM) imaging shows that the length of Au NRs decreases with oxidation and their diameter stays almost constant, which suggests that oxidation starts at the ends of Au NRs. The size distributions of shor...

Selective shortening of single-crystalline gold nanorods by mild oxidation.

Rapid‐Setting, Mesoporous, Bioactive Glass Cements that Induce Accelerated In Vitro Apatite Formation

Well-ordered mesostructured/mesoporous silica nanofibers have been synthesized in a quiescent dilute aqueous cationic surfactant/silica precursor reaction mixture under strong acidic conditions. These nanofibers have diameters ranging from 50 to 300 nm and lengths up to millimeters. Transmission electron microscopy (TEM) studies show that the nanofibers exhibit either a circular architecture with the pore channels running in a circular direction around the fiber axis or a longitudinal architecture with the pore channels running parallel to the fiber axis. The pore channels in both arrangements are hexagonally packed. The circular or longitudinal architecture can be selectively obtained during synthesis by varying reaction temperature or using inorganic salts as additives.

Structure-Selective Synthesis of Mesostructured/Mesoporous Silica Nanofibers

Stable TiVCTx/poly-o-phenylenediamine composites with three-dimensional tremella-like architecture for supercapacitor and Li-ion battery applications

The roles of gold and silver nanoparticles on ZnIn2S4/silver (gold)/tetra(4-carboxyphenyl)porphyrin iron(III) chloride hybrids in carbon dioxide photoreduction.

Jinping Zhang

Papers

Selective shortening of single-crystalline gold nanorods by mild oxidation.

Rapid‐Setting, Mesoporous, Bioactive Glass Cements that Induce Accelerated In Vitro Apatite Formation

Structure-Selective Synthesis of Mesostructured/Mesoporous Silica Nanofibers

Stable TiVCTx/poly-o-phenylenediamine composites with three-dimensional tremella-like architecture for supercapacitor and Li-ion battery applications

The roles of gold and silver nanoparticles on ZnIn2S4/silver (gold)/tetra(4-carboxyphenyl)porphyrin iron(III) chloride hybrids in carbon dioxide photoreduction.