One-dimensional assemblies of nanoparticles: Preparation, properties, and promise

Nanoparticle (NP) assemblies are of considerable interest for both fundamental research and applications, since they provide direct bridges between nanometer-scale objects and the macroscale world. Unlike two-dimensional or three-dimensional NP assemblies, which have been extensively studied and reviewed, reports on one-dimensional (1D) NP assemblies are rather rare, even though these assemblies are likely to play critical roles in the improvement of the efficiencies of various electronic, optoelectronic, magnetic, and other devices based on single NPs or their composites. Additionally, 1D assemblies of NPs, i.e., chains, can significantly help in the understanding of a number of biological processes and fundamental quantum mechanics of nanometer-scale systems. The difficulties are very evident when one wants to realize anisotropic 1D assemblies from presumably isotropic, zero-dimensional NPs. In this context, the authors present a systemic review of current research on 1D NP assemblies. Their preparation methods are classified and novel characteristics of NP chains, such as collective properties and directional transfer of photons, electrons, spins, etc., are elucidated. Current problems underlying the fundamental research and practical applications of 1D NP assemblies are also addressed.