Direct visualization of ligands on gold nanoparticles in a liquid environment.

The interactions between gold nanoparticles, their surface ligands and the solvent critically influence the properties of these nanoparticles. Although spectroscopic and scattering techniques have been used to investigate their ensemble structure, a comprehensive understanding of these processes at the nanoscale remains challenging. Electron microscopy makes it possible to characterize the local structure and composition but is limited by insufficient contrast, electron beam sensitivity and the requirement for ultrahigh-vacuum conditions, which prevent the investigation of dynamic aspects.

Spatially reconfigurable antiferromagnetic states in topologically rich free-standing nanomembranes.

Antiferromagnets hosting real-space topological textures are promising platforms to model fundamental ultrafast phenomena and explore spintronics. However, they have only been epitaxially fabricated on specific symmetry-matched substrates, thereby preserving their intrinsic magneto-crystalline order. This curtails their integration with dissimilar supports, restricting the scope of fundamental and applied investigations.

Observation of grain boundary plasmon and associated deconvolution techniques for low-loss electron energy-loss (EEL) spectra acquired from grain boundaries.

Spatially resolved valence electron energy-loss spectroscopy (VEELS) was used to acquire low-loss EEL spectra from Al grain boundaries (GBs) with different GB energies. The loss signal from the GB is highly delocalized and is mixed with the bulk loss, therefore requiring separation. Three different separation techniques, i.

All-Dielectric Nanostructures with a Thermoresponsible Dynamic Polymer Shell.

We suggest a new strategy for creating stimuli-responsive bio-integrated optical nanostructures based on Mie-resonant silicon nanoparticles covered by an ensemble of similarity negatively charged polyelectrolytes (heparin and sodium polystyrene sulfonate). The dynamic tuning of the nanostructures' optical response is due to light-induced heating of the nanoparticles and swelling of the polyelectrolyte shell. The resulting hydrophilic/hydrophobic transitions significantly change the shell thickness and reversible shift of the scattering spectra for individual nanoparticles up to 60 nm.

Binary Chiral Nanoparticles Exhibit Amplified Optical Activity and Enhanced Refractive Index Sensitivity.

Metallic chiral nanoparticles (CNPs) with a nominal helical pitch (P) of sub-10 nm contain inherent chirality and are promisingly applied to diverse prominent enantiomer-related applications. However, the sub-wavelength P physically results in weak optical activity (OA) to prohibit the development of these applications. Herein, a facile method to amplify the CNPs' OA by alloying the host CNPs with metals through a three-step layer-by-layer glancing angle deposition (GLAD) method is devised.

Chirality Transfer in Galvanic Replacement Reactions.

Demand for the transfer of chirality from a pre-engineered nanoparticle to any other metal is of fundamental importance for developing a wide range of chirality-related applications. Herein, we show that binary alloy chiral nanoparticles (CNPs) with an engineerable composition can be formed from metallic CNPs with intrinsic structural chirality serving as sacrificial templates (STs), via a galvanic replacement reaction (GRR). This GRR-mediated chirality transfer is a general phenomenon and results in the formation of Cu-Ag CNPs with solid morphology and mesoporous CNPs made of Ag-Au, Ag-Pt, and Ag-Pd.

Determining the Volume Expansion at Grain Boundaries Using Extended Energy-Loss Fine Structure Analysis.

Grain boundaries (GBs) play an important role in material behavior, so considerable effort has gone into determining their structure and properties. Studies of GBs have revealed a correlation between the GB energy and expansion of the planes normal to the GB, or the so-called normal volume expansion. In this investigation, the volume expansion at several GBs was experimentally determined using extended energy-loss fine structure (EXELFS) analysis in a scanning/transmission electron microscope, allowing changes in the nearest-neighbor (n.