A welding phenomenon of dissimilar nanoparticles in dispersion

Abstract

The oriented attachment of small nanoparticles (NPs) is recognized as an important mechanism involved in the growth of inorganic nanocrystals. However, non-oriented attachment of dissimilar NPs has been rarely observed in dispersion. This communication reports a welding phenomenon occurred directly between as-synthesized dispersions of single-component Au and chalcogenide NPs, which leads to the formation of asymmetric Au-chalcogenide hybrid NPs (HNPs). The welding of dissimilar NPs in dispersion is mainly driven by the ligand desorption-induced conformal contact between NPs and the diffusion of Au into chalcogenide NPs. The welding process can occur between NPs with distinct shapes or different capping agents or in different solvent media. A two-step assembly-welding mechanism is proposed for this process, based on our in situ electron spin resonance measurements and ab initio molecular dynamics simulation. The understanding of NP welding in dispersion may lead to the development of unconventional synthetic tools for the fabrication of hybrid nanostructures with diverse applications.

Heterostructures Built through Site‐Selective Deposition on Anisotropic Plasmonic Metal Nanocrystals and Their Applications

“…The welding process is driven by the instability of NCs and the diffusion of metal atoms on the common crystalline facets of neighboring NCs. [103,104] The early welding method based on oriented attachment is, however, largely limited to the same types of nanoparticles due to the requirement of lattice matching. [12,105,106] So far, there have been only a few works on welding of dissimilar nanoparticles through a nonoriented attachment mechanism.…”

“…For example, multicomponent Au-chalcogenide hybrid nanostructures with specific shapes and morphologies have been formed through welding of dissimilar Au and chalcogenide nanoparticles. [104] After the mixture of citrate/ PEG-functionalized Au nanoparticles with Ag 2 S nanoparticles that are modified with bovine serum albumin (BSA), Au-Ag 2 S oligomer-like hybrid nanostructures are formed through weak electrostatic attraction between the dissimilar nanoparticles and repulsion between the same types of nanoparticles (Figure 6a). During the process, atom diffusion between the Au and Ag 2 S domain occurs and the hybrid nanostructures are subsequently welded.…”

“…Therefore, local field enhancement that is strongly affected by the morphology of anisotropic plasmonic heterostructures can bring huge impact on the SERS enhancement factor. In addition, charge transfer resonance can also arise from the electronic interaction between the molecular orbital and the metal conduction band and couple to the vibrational states of adsorbed [104] Copyright 2019, Springer Nature. e) Schematic showing the surface etching method.…”

“…The hybrid nanostructures in (a)-(d) are obtained through welding of Au nanospheres, Au NRs, and Au nanowires with Ag 2 S nanoparticles, respectively. a-d) Reproduced with permission [104]. Copyright 2019, Springer Nature.…”

Controlled Synthesis of Au Nanocrystals-Metal Selenide Hybrid Nanostructures toward Plasmon-Enhanced Photoelectrochemical Energy Conversion

“…Many efforts have also been made to investigate the physical and chemical properties of the hybrid NCs [2,[35][36][37][38], and the results indicated that their properties are highly dependent on the size, shape, composition, and spatial distribution of each component [24,30,[39][40][41]. Therefore, a large number of schemes keep emerging towards synthesis of these hybrid nanostructures under the joint endeavours of the majority of scientific researchers [42][43][44][45][46]. Among them, seed-mediated selective growth of semiconductor shells based on metal nanocrystals has unique advantages, owing to abundant and controllable plasmon properties from the designed metal nanostructures [33,44,47,48].…”