Particle Shape Control via Etching of Core@Shell Nanocrystals

Abstract

The application of nanocrystals as heterogeneous catalysts and plasmonic nanoparticles requires fine control of their shape and chemical composition. A promising idea to achieve synergistic effects is to combine two distinct chemical and/or physical functionalities in bimetallic core@shell nanocrystals. Although techniques for the synthesis of single-component nanocrystals with spherical or anisotropic shape are well-established, new methods are sought to tailor multicomponent nanocrystals. Here, we probe etching in a controlled redox environment as a synthesis technique for multicomponent nanocrystals. Our Monte Carlo computer simulations demonstrate the appearance of characteristic non-equilibrium intermediate microstructures that are further thermodynamically tested and analyzed with molecular dynamics. Convex platelet, concave polyhedron, pod, cage, and strutted-cage shapes are obtained at room temperature with fully coherent structure exposing crystallographic facets and chemical elements along distinct particle crystallographic directions. We observe that structural and dynamic properties are markedly modified compared to the untreated compact nanocrystal.

Synthesis and Single-Particle Surface-Enhanced Raman Scattering Study of Plasmonic Tripod Nanoframes with Y-Shaped Hot-Zones

“…E vertex > E chem ), but oxidation of the Au edge occurs at the same time because E chem > E edge . In Figure f, the left vertical line indicates the standard redox potential of E vertex and E edge , assuming that Au atoms on the different crystalline facets have different standard redox potentials, − positioning E vertex higher than E edge . The right vertical line shows E chem , which can be tuned by experimental conditions such as temperature, pH, and concentration.…”

Efficient solution of particle shape functions for the analysis of powder total scattering data

“…Accurate structural information is the foundation for the development of materials for heterogeneous catalysis, semiand superconduction, sensing, and photonic and plasmonic applications (Chen et al, 2017;Luo & Guo, 2017;Billinge & Egami, 1993;Gong et al, 2015;Hajfathalian et al, 2016;Gamler et al, 2020;Leonardi & Engel, 2018). The synthesis of nanomaterials with fine microstructural features requires advances in powder scattering techniques to fully resolve the particle structure, microstructure and lattice distortion (Scardi et al, 2015;Solla-Gullon et al, 2015).…”

Whole pair distribution function modeling: the bridging of Bragg and Debye scattering theories

“…The synthesis of nanostructured materials with precise control of microstructural properties benefits from the use of powderscattering methods to fully resolve the structure of the millions to billions of crystals in a typical powder sample (Habas et al, 2007;Solla-Gullon et al, 2015;Gamler et al, 2019;Leonardi & Engel, 2018). The crystalline structure determines the emergence of diffraction peaks in the scattering profile.…”