Structural reordering in monolayers of gold nanoparticles during transfer from water surface to solid substrate

Area of Science:

• Materials Science
• Nanotechnology
• Surface Science

Background:

• Monolayers of gold nanoparticles (AuNPs) are crucial in nanotechnology.
• Understanding their structural dynamics during transfer is key for device fabrication.

Purpose of the Study:

• To investigate the structural reordering of gold nanoparticle monolayers during transfer from water to a solid substrate.
• To elucidate the dynamics of in-plane and out-of-plane structural changes.

Main Methods:

• Utilized synchrotron X-ray scattering techniques, including Grazing Incidence Diffraction (GID) and Grazing Incidence X-ray Off-specular Scattering (GIXOS).
• Performed time-resolved measurements to track structural evolution.
• Supported findings with microscopy measurements.

Main Results:

• Initial Grazing Incidence Diffraction (GID) data suggested lattice expansion.
• Grazing Incidence X-ray Off-specular Scattering (GIXOS) and microscopy revealed in-plane compactification and out-of-plane movement.
• Observed a transition from a triangular to a square-like lattice structure over time.
• Electron density changes correlated with the lattice transition.

Conclusions:

• A model of two-dimensional short-range structural reordering from triangular to square-like symmetry explains the observed phenomena.
• The structural transition significantly alters the electron density distribution within the gold nanoparticle monolayers.