Methods and Structures for Self-assembly of Anisotropic 1D Nanocrystals

Abstract

In the nanoscience and nanotechnology, the study of nanocrystal selfassembly has been regarded as a key technology in leading future industrial development. The colloidal self-assembly techniques, particularly for one-dimensional (1D) building blocks, have been widely adopted for the systematic fabrication of functional nanocrystals and received an extensive research attention. However, the increase in the building blocks' anisotropy, e.g. from sphere to rod/ wire, has dramatically leveled up the difficulty in organizing them into ordered structures. To realize tailored 1D nanocrystal self-assembled structures, a profound understanding and detailed design of self-assembly mechanism and procedures are much needed. Here, a thorough review over 1D nanocrystal self-assembly methods and alignments are present to achieve large-scale functional structures. Through different techniques, such as evaporation, template, electric field, LangmuirBlodgett film and chemical bonding, nanocrystals with various shapes can be selfassembled on substrates, at interfaces and in solutions. These assembled structures that have been achieved so far, can exhibit different degrees of alignments, such as stripe pattern as non-close-packed structure, horizontal, vertical alignments as close-packed monolayers, nematic, semectic alignments, AB stacking of vertical alignments, three-dimensional (3D) assembly as close-packed multilayers. In general, these self-assembly techniques can reach much small dimension and create microstructures that possess unique properties different from their individual building blocks.