Time-resolved in situ nanoparticle size evolution during magnetron sputtering onto liquids.

Area of Science:

• Materials Science
• Nanotechnology
• Physical Chemistry

Background:

• Magnetron sputtering of metals onto liquids (SoL) presents open questions on nanoparticle (NP) nucleation, growth mechanisms, and liquid property influences.
• Understanding NP formation is crucial for controlling material properties in liquid-phase synthesis.

Purpose of the Study:

• To investigate the in situ, real-time particle size evolution of silver nanoparticles (Ag NPs) during and after magnetron sputtering onto silicone oil.
• To analyze the effects of deposition rate and stirring speed on the particle size distribution (PSD) and growth kinetics of Ag NPs.

Main Methods:

• In situ Light Extinction Spectroscopy (LES) for real-time particle size distribution (PSD) measurement.
• Ex situ Transmission Electron Microscopy (TEM) and in situ time-resolved absorption spectra for PSD validation.
• Analysis of De Brouckere mean diameters to monitor Ag NP size evolution over time.

Main Results:

• Ag NPs larger than 20 nm were detected, exhibiting poly-disperse size distributions.
• NP aggregation and growth occur at the plasma-liquid interface and within the silicone oil.
• Higher deposition rates lead to larger Ag NPs, while stirring aids disaggregation and promotes smaller NPs (<20 nm).
• Observed low colloidal stability of Ag NPs in silicone oil.

Conclusions:

• The study provides novel insights into Ag NP formation dynamics in silicone oil via the SoL process.
• Deposition rate and stirring speed are critical parameters influencing Ag NP size and aggregation.
• The findings highlight challenges in controlling Ag NP size and stability in silicone oil for potential applications.