Method Development for the Synthesis of Colloidal Multimetallic Nanocrystals

• Applicant: Guillermo González-Rubio, Ph.D.
• Subject Area: Solid State and Surface Chemistry, Material Synthesis ; Synthesis and Properties of Functional Materials ; Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry
• Term: from 2021 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 460932591

• Final Report Year: 2023

Final Report Abstract

The main objective of the research project was to design a synthetic route for the fabrication of colloidal multimetallic nanocrystals (MM NCs) with different sizes, shapes, compositions, and elemental distributions. Notably, the envisaged route relied on the self-assembly of colloidal NCs into MM supraparticles (SPs). However, during the early stage of the project development, the co-assembly of different noble metal NCs in a controlled and reproducible manner became an unexpected and important challenge. Because the formation of SPs typically requires NCs dispersed in non-polar solvents, it is critical to cover NC surfaces with a dense shell of hydrophobic ligands. Unfortunately, commercially available surface ligands often used to form single-component SPs limit the project's scope to metal NCs with dimensions typically below 10 nm. Research efforts were then focused on the development of a synthesis route to obtain surface molecules capable of imparting sufficient colloidal stability to different metal NCs in non-polar solvents and thereby facilitate their coassembly into densely packed SPs (i.e., forming NC superlattices). The synthesized polymeric surface ligands have enabled us to stabilize large metal NCs in non-polar solvents such as hexadecane or the formation of binary highly ordered SPs from metal NCs with dimensions above 50 nm. Moreover, narrow-size dispersity SPs were obtained through the implementation of a microfluidic system. Overall, these results represent fundamental findings for the future success of the proposed MM NC synthesis method. Moreover, due to the critical role of surface ligands in colloidal NC technology, we believe our findings could be of interest to a broad spectrum of researchers in the field of colloidal nanomaterials.

Publications

• Engineering of plasmonic gold nanocrystals through pulsed laser irradiation. Applied Physics Letters, 121(20).
  González-Rubio, Guillermo & Albrecht, Wiebke
  
• Self-Assembly of Colloidal Nanocrystals into 3D Binary Mesocrystals. Accounts of Chemical Research, 55(12), 1599-1608.
  Ni, Bing; Gonzalez-Rubio, Guillermo & Cölfen, Helmut