Nature controls the assembly of complex architectures through self-limiting processes, however few artificial strategies to mimic these processes have been reported to date. Here, we demonstrate a system comprised of two types of nanocrystals (NCs), where the self-limiting assembly of one NC component controls the aggregation of the other. Our strategy uses semiconducting InP/ZnS core-shell NCs (3 nm) as effective assembly-modulators and functional nanoparticle surfactants in cucurbit[n]uril-triggered aggregation of AuNCs (5-60 nm)
Corrosion is a significant problem for the stability of structural metals and potentially for functional nanomaterials in operating environments. When two metals with different electrochemical potentials form a junction, galvanic corrosion occurs, resulting in the sacrificial dissolution of the metal with a higher oxidation potential (lower electrode potential). Here, it is shown that bimetallic hetero-nanostructures composed of phase-segregated metals undergo galvanic corrosion in aqueous environments. Such selective etching of the sacrificial metal in heterojunction particles leads to the formation of unusual and kinetically stabilized half-spheroid particles. By using a fluid cell and in situ scanning transmission electron microscopy, a two-stage corrosion process can be observed where the Cu experiences a fractal breakdown before the Ag corrodes due to the lack of a protective oxide layer. However, when treated with a mild Ar plasma, the stability of these structures against corrosion is enhanced due to the conversion of the amorphous native oxide to a denser, thin layer of CuO on the Cu surface. Taken together, this work highlights the importance of considering the effects of galvanic corrosion on the stability of multicomponent nanoparticles, and it shows how mass transport in a nanoscale system is influenced by redox processes.
Solid‐state single photon emitters (SPEs) within atomically thin transition metal dichalcogenides (TMDs) have recently attracted interest as scalable quantum light sources for quantum photonic technologies. Among TMDs, WSe2 monolayers (MLs) are promising for the deterministic fabrication and engineering of SPEs using local strain fields. The ability to reliably produce isolatable SPEs in WSe2 is currently impeded by the presence of numerous spectrally overlapping states that occur at strained locations. Here nanoparticle (NP) arrays with precisely defined positions and sizes are employed to deterministically create strain fields in WSe2 MLs, thus enabling the systematic investigation and control of SPE formation. Using this platform, electron beam irradiation at NP‐strained locations transforms spectrally overlapped sub‐bandgap emission states into isolatable, anti‐bunched quantum emitters. The dependence of the emission spectra of WSe2 MLs as a function of strain magnitude and exposure time to electron beam irradiation is quantified and provides insight into the mechanism for SPE production. Excitons selectively funnel through strongly coupled sub‐bandgap states introduced by electron beam irradiation, which suppresses spectrally overlapping emission pathways and leads to measurable anti‐bunched behavior. The findings provide a strategy to generate isolatable SPEs in 2D materials with a well‐defined energy range.
A versatile approach for synthesizing Yb 3+ -and Er 3+ -doped NaYF 4 upconversion nanoparticle (UCNP) arrays is presented. The nanoparticles are positioned at precisely defined locations through the tip-directed deposition of polyol nanoreactors and subsequent thermal conversion. This method is based on conducting a solution-phase polyol synthesis in nanometerscale reactors, which provide isolated and confined reaction vessels for the thermal decomposition of a fluoride precursor and the coarsening of fluoride nanoparticles. When the nanoreactors are annealed at 350 °C, the polyol degrades, and the nanoparticles, which exhibit upconversion properties, crystallize. Single nanoparticles are attained in each nanoreactor by tuning the precursor concentration, nanoreactor size, and temperature ramping rate. This strategy enhances the scope of nanostructures that can be synthesized by tip-directed routes and, when combined with massively parallel pen approaches such as polymer pen lithography, provides a generalizable platform for the high-throughput synthesis, screening, and discovery of nanomaterials for photonics and other applications.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.