Size-Focusing of Au Nanoparticles through Dissolution-Renucleation Process Imaged with In Situ TEM

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Engineering

Background:

• Nanoparticle (NP) size and morphology control is crucial for their applications.
• Post-synthesis ligand addition is a common method for tuning NP characteristics.
• The underlying mechanism of ligand-induced NP transformation remains poorly understood.

Purpose of the Study:

• To elucidate the mechanism of nanoparticle transformation induced by ligand addition.
• To provide mechanistic insights into the synthesis of monodisperse nanoparticles.
• To highlight the utility of in situ liquid-phase transmission electron microscopy (TEM) for studying nanoscale liquid-phase processes.

Main Methods:

• In situ liquid-phase transmission electron microscopy (TEM) was employed.
• The transformation of large polydisperse nanoparticles upon ligand addition was directly observed.
• Real-time imaging captured the dynamic changes at the nanoscale.

Main Results:

• The transformation proceeds via complete dissolution of initial nanoparticles.
• New, smaller, monodisperse nanoparticles subsequently nucleate and grow.
• Direct imaging revealed the dissolution-renucleation-growth pathway.

Conclusions:

• The study clarifies the mechanism of ligand-induced nanoparticle size and morphology tuning.
• Understanding this mechanism is vital for controlled synthesis of monodisperse nanoparticles.
• In situ liquid-phase TEM is a powerful tool for investigating dynamic nanoscale phenomena in liquids.