Self-Assembly of Quantum Dot-Gold Hetero-Dimer Nanocrystals with Orientational Order

• Published in: Nano letters 2018-07
• Main Authors: Chen, Ou, Zhu, Hua, Fan, Zhaochuan, Yuan, Yucheng, Wilson, Mitchell A, Hills-Kimball, Katie, Wei, Zichao, He, Jie, Li, Ruipeng, Gruenwald, Michael
• Format: Article
• Language: English
• ISSN: 1530-6992

Self-assembly of nanocrystals into ordered superlattices is a powerful strategy for the production of functional nanomaterials. Assembly of well-ordered target structures, however, requires control over the building blocks' size and shape, as well as their interactions. While nanocrystals with homogeneous composition are now routinely synthesized with high precision and assembled into various ordered structures, high-quality multi-component nanocrystals and their ordered assemblies are rarely reported. In this paper, we demonstrate the synthesis of quantum-dot-gold (QD-Au) hetero-dimers. These hetero-dimers possess uniform shape and narrow size distribution, and capped with oleylamine and dodecyltrimethylammonium bromide (DTAB). Assembly of the hetero-dimers results in a superlattice with long-range orientational alignment of dimers. Using synchrotron-based X-ray measurements, we characterize the complex superstructure formed from the dimers. Molecular dynamics simulations of a coarse-grained model suggest that anisotropic interactions between the quantum-dot and gold components of the dimer drive the superlattice formation. The high degree of orientational order demonstrated in this work is a potential route to nanomaterials with useful opto-electronic properties.