Atomic Structure and 3D Shape of a Multibranched Plasmonic Nanostar from a Single Spatially Resolved Electron...

Area of Science:

• Nanotechnology
• Materials Science
• Physical Chemistry

Background:

• Plasmonic nanoparticles (NPs) enhance optical sensor sensitivity.
• Characterizing complex nanostructures like nanostars (NS) is challenging.
• Understanding NP structure is key to optimizing their properties.

Purpose of the Study:

• To achieve detailed 3D structural determination of an individual complex nanostar.
• To investigate the atomic arrangement and growth mechanism of a 6-branched gold-silver nanostar.
• To demonstrate the utility of 4D-STEM for complex NP analysis.

Main Methods:

• Utilized scanning transmission electron microscope diffraction mapping (4D-STEM) on a single nanostar.
• Analyzed diffraction data to reconstruct the 3D shape and atomic positions.
• Employed low-dose imaging to preserve beam-sensitive materials.

Main Results:

• Determined the icosahedral core structure and decahedral rod legs of the AuAg nanostar.
• Revealed an anomalous anisotropic distribution of the nanostar legs.
• Identified the interplay between icosahedral symmetry and surfactant unzipping in leg formation.

Conclusions:

• 4D-STEM provides unprecedented detail on individual complex nanostructures.
• The study elucidates the growth mechanism of branched nanostars.
• This method is promising for analyzing diverse and beam-sensitive nanoparticles for advanced applications.