Symmetry control of nanorod superlattice driven by a governing force

Yujia Liang,Qian Liu,Fengyou Yang,Xiaochun Wu,Yong Xie,Ke Deng,Shuai Hou,Dongxue Chen,Tao Wen,Chuanfei Guo,Ivan I Smalyukh

doi:10.1038/s41467-017-01111-4

Abstract

Nanoparticle self-assembly promises scalable fabrication of composite materials with unique properties, but symmetry control of assembled structures remains a challenge. By introducing a governing force in the assembly process, we develop a strategy to control assembly symmetry. As a demonstration, we realize the tetragonal superlattice of octagonal gold nanorods, breaking through the only hexagonal symmetry of the superlattice so far. Surprisingly, such sparse tetragonal superstructure exhibits much higher thermostability than its close-packed hexagonal counterpart. Multiscale modeling reveals that the governing force arises from hierarchical molecular and colloidal interactions. This force dominates the interactions involved in the assembly process and determines the superlattice symmetry, leading to the tetragonal superlattice that becomes energetically favorable over its hexagonal counterpart. This strategy might be instructive for designing assembly of various nanoparticles and may open up a new avenue for realizing diverse assembly structures with pre-engineered properties.

Highlights

Nanoparticle self-assembly promises scalable fabrication of composite materials with unique properties, but symmetry control of assembled structures remains a challenge
Only hexagonal symmetry of gold nanorods (GNRs) superlattice has been achieved, which is determined by the principle of minimum potential energy
Using fully-covered GNRs (FC GNRs), a typical hexagonal GNR assembly obtained in quasi-equilibrium condition (Fig. 1a) is demonstrated, which is in agreement with the previous results[27, 29, 34, 35]

Summary

Introduction

Nanoparticle self-assembly promises scalable fabrication of composite materials with unique properties, but symmetry control of assembled structures remains a challenge. If we could introduce a strong force to dominate the assembly process, it might be possible to achieve a desired configuration with the minimum potential energy, and control the superlattice symmetry. We present an assembly strategy to achieve symmetry control of the GNRs superlattice.

Results

Conclusion