This article presents an overview of current research activities that center on monodispersed colloidal spheres whose diameter falls anywhere in the range of 10 nm to 1 mm. It is organized into three parts: The first part briefly discusses several useful methods that have been developed for producing monodispersed colloidal spheres with tightly controlled sizes and well-defined properties (both surface and bulk). The second part surveys some techniques that have been demonstrated for organizing these colloidal spheres into two-and three-dimensionally ordered lattices. The third part highlights a number of unique applications of these crystalline assemblies, such as their uses as photonic bandgap (PBG) crystals; as removable templates to fabricate macroporous materials with highly ordered and three-dimensionally interconnected porous structures; as physical masks in lithographic patterning; and as diffractive elements to fabricate new types of optical sensors. Finally, we conclude with some personal perspectives on the directions towards which future research in this area might be directed.

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This paper discusses the potential use of non‐spherical colloids (see Figure) as the building blocks in self‐assembly to fabricate three‐dimensional photonic crystals with bandgaps located in the optical regime. The methods of producing non‐spherical colloids as monodisperse samples, and with well‐defined shapes and tightly controlled dimensions are presented, and the methods employed to organize these non‐spherical colloids into 3D crystalline lattices are discussed.

It has been our greatest pleasure to put together this special issue that is intended to cover all major aspects of research devoted to the chemistry, physics, and materials science associated with nanowires. Nanostructures (i.e., structures with at least one dimension in the range of 1±100 nm) have attracted steadily growing interest due to their peculiar, fascinating properties, as well as their unique applications complementary to the bulk materials. The ability to generate such small structures is central to the advance of many areas in modern science and technology. There are a large number of opportunities that could be realized by making new types of nanostructures, or by down-sizing currently existing structures into the nanoscale regime. In comparison with zero-dimensional (0D) nanostructures (or the so-called quantum dots or nanoparticles), 1D nanostructures (including wires, rods, belts, and tubes) provide a better model system for investigating the dependence of electronic transport, optical, and mechanical properties on size confinement and dimensionality. Nanowires, in particular, should play an important role as both interconnects and active components in fabricating nanoscale electronic and photonic devices. Until very recently, the advance in the utilization of nanowires had been relatively slow, probably due to difficulties associated with the synthesis of such nanostructures with well-controlled size, phase purity, crystallinity, and chemical composition. Solutions to these synthetic challenges require a detailed, fundamental understanding and good control of the nucleation and growth processes at the nanometer scale, whether it is in the solution or vapor phase. Due to the lack of nanowires with excellent monodispersity, it has also been difficult to draw conclusions on the structure±property correlations for this class of nanostructures, and to fully exploit their potential in fabricating new types of functional devices. These challenges and opportunities have motivated many groups to launch research projects specifically focused on the synthesis, characterization, and utilization of nanowires.This special issue includes contributions from many leading figures in this area. Xia and Yang give a comprehensive review on recent research activities that involve the synthesis, characterization, self-assembly, physical properties, and applications of nanowires. The rest of the articles cover four important research themes: i) vapor-phase routes to the synthesis of nanowires; ii) solution-based methods for forming nanowires; iii) templated-directed synthesis of nanowires; and iv) self-assembly with nanowires as the building blocks and new physics associated with 1D nanostructures.In the first theme, involving vapor phase growth, Yang and co-workers discuss how several simple processes could be adopted to grow nano-and microscale hierarchical structures based on ZnO nanorods; Wang presents a brief overview of recent work related to the synthesis of metal oxide nanobelts and nanowires; Liu and co-work...