Fabrication of one-dimensional nanostructures standing vertically on a substrate through layer-by-layer deposition

Layer-by-layer deposition has been widely used to prepare heterogeneous nanocomposites with controllable properties, where the controllability of nanocomposite properties can be further enhanced by combining the self-assembly of hard materials, such as nanocrystals, and soft materials, such as polymer matrices. However, the self-assembled structure of nanocrystals in a polymer matrix is limited by thermodynamics. Herein, we introduced the strong interaction between nanocrystals and a substrate to generate a thermodynamically unfavorable one-dimensional nanostructure standing vertically on the substrate. Two different shapes-"wire-like" and "steeple-like" or "antenna-like"-of one-dimensional nanostructures standing vertically on the substrate can be obtained using cube-like nanocrystals as building blocks and carefully controlling their size in each deposited layer. This low-cost and massively parallel scale synthesis method to generate one-dimensional nanostructures standing vertically on a substrate can be used to replace the expensive and time-consuming "lithography" synthesis method. This synthesis method also provides a simple way to design and fabricate one-dimensional nanostructures with desired properties standing vertically on a substrate by controlling nanocrystal properties in each deposited layer. LBL deposition has been widely used to prepare nanocomposites with controllable properties, where the controllability of nanocomposite properties can be further enhanced by combining the self-assembly of hard materials in soft materials.