Probing planar defects in nanoparticle superlattices by 3D small-angle electron diffraction tomography and real space...

Area of Science:

• Materials Science
• Nanotechnology
• Crystallography

Background:

• Characterizing mesoscale structural features in nanomaterials is crucial for understanding their properties.
• Self-assembled nanoparticle superlattices exhibit complex structural arrangements.
• Lattice distortions can significantly impact the performance of nanostructured materials.

Purpose of the Study:

• To extend 3D electron diffraction data acquisition and processing for mesoscale structural characterization.
• To quantify lattice distortions in superlattices of self-assembled spherical palladium nanoparticles.
• To investigate the nature and origin of planar defects in these superlattices.

Main Methods:

• Three-dimensional small-angle electron diffraction tomography (3D SA-EDT) was employed.
• Transmission electron microscopy (TEM) real-space imaging was utilized.
• Analysis focused on quantifying lattice distortions and identifying defect structures.

Main Results:

• 3D SA-EDT successfully quantified lattice distortions in palladium nanoparticle superlattices.
• A high density of stacking faults was observed, linked to competing fcc and hcp packing during assembly.
• The orientation of stacking faults was determined, allowing comparisons with metallic systems.

Conclusions:

• 3D SA-EDT is a powerful technique for mesoscale structural analysis of nanoparticle assemblies.
• Stacking faults in these superlattices share similarities with Shockley partial dislocations in metals.
• Understanding these defects provides insights into nanoparticle self-assembly mechanisms.