Separation of Nanoparticle Seed Pseudoisomers via Amplification of Their Crystallographic Differences

Zhihua Cheng; Matthew R Jones

doi:10.1021/jacs.3c09945

Separation of Nanoparticle Seed Pseudoisomers via Amplification of Their Crystallographic Differences

J Am Chem Soc. 2023 Dec 20;145(50):27702-27707. doi: 10.1021/jacs.3c09945. Epub 2023 Dec 6.

Authors

Zhihua Cheng¹, Matthew R Jones^{1

2}

Affiliations

¹ Department of Chemistry, Rice University, MS 6000, Main Street, Houston, Texas 77005, United States.
² Department of Material Science and Nanoengineering, Rice University, MS 6000, Main Street, Houston, Texas 77005, United States.

PMID: 38055680
DOI: 10.1021/jacs.3c09945

Abstract

Seed-mediated syntheses rely on small nanoparticle (NP) precursors that act as templates for growth but are often inhomogeneous with respect to their internal twinning structures (e.g., single crystalline, multiply twinned), leading to nonuniform product morphologies. To address this, we developed a method for separating seed NPs of the same approximate size (∼ 10 nm) but with different interior twinning (i.e., NP "pseudoisomers") by exaggerating their crystallographic differences through heteroexpitaxial metal overgrowth. Specifically, single crystalline and pentatwinned Au seeds that are natively inseparable via traditional methods exhibit drastically different Ag shell morphologies that allow for their selective precipitation through colloidal depletion forces. Oxidation of the Ag shell from separated particles results in seeds that are both size uniform and crystallographically pure (>99%), allowing for the controlled synthesis of a library of O_h- and D_5h-symmetric gold NPs bearing {111}, {110}, {730}, {310}, {720}, and {100} facets, several of which have no precedent in the literature. These results lay the foundation for precision nanosynthesis by establishing a new paradigm for the purification of NP precursors.