Three-dimensional controlled growth of monodisperse sub-50 nm heterogeneous nanocrystals.

Deming Liu,Dayong Jin,Wei Ren,Yuhai Zhang,Xiaogang Liu,Shixue Dou,Yi Du,Xian Qin,James A Piper,Chenshuo Ma,Shihui Wen,Xiaoxue Xu,Ewa M Goldys

doi:10.1038/ncomms10254

Abstract

The ultimate frontier in nanomaterials engineering is to realize their composition control with atomic scale precision to enable fabrication of nanoparticles with desirable size, shape and surface properties. Such control becomes even more useful when growing hybrid nanocrystals designed to integrate multiple functionalities. Here we report achieving such degree of control in a family of rare-earth-doped nanomaterials. We experimentally verify the co-existence and different roles of oleate anions (OA−) and molecules (OAH) in the crystal formation. We identify that the control over the ratio of OA− to OAH can be used to directionally inhibit, promote or etch the crystallographic facets of the nanoparticles. This control enables selective grafting of shells with complex morphologies grown over nanocrystal cores, thus allowing the fabrication of a diverse library of monodisperse sub-50 nm nanoparticles. With such programmable additive and subtractive engineering a variety of three-dimensional shapes can be implemented using a bottom–up scalable approach.

Highlights

The ultimate frontier in nanomaterials engineering is to realize their composition control with atomic scale precision to enable fabrication of nanoparticles with desirable size, shape and surface properties
We find that oleate anions (OA À ), the dissociated form of oleic acid molecules (OAH), have variable, dynamic roles in mediating the growth of AREF4 nanocrystals
This new method is based on a selective epitaxial core–shell growth process in the presence of oleic acid, commonly used as a surfactant during the synthesis of b-AREF4 nanocrystals[32]

Summary

Introduction

The ultimate frontier in nanomaterials engineering is to realize their composition control with atomic scale precision to enable fabrication of nanoparticles with desirable size, shape and surface properties. We identify that the control over the ratio of OA À to OAH can be used to directionally inhibit, promote or etch the crystallographic facets of the nanoparticles This control enables selective grafting of shells with complex morphologies grown over nanocrystal cores, allowing the fabrication of a diverse library of monodisperse sub-50 nm nanoparticles. We find that oleate anions (OA À ), the dissociated form of oleic acid molecules (OAH), have variable, dynamic roles in mediating the growth of AREF4 nanocrystals This allows us to introduce a molecular approach to tailoring the shape and composition of AREF4 nanocrystals. We demonstrate that the precise control over the shell thickness and the particle shape can be achieved by deliberately switching the passivation, additive and subtractive roles of these surfactants

Methods

Results

Conclusion