Quantitative analysis of nanoparticle growth through plasmonics

Area of Science:

• Surface science
• Nanoparticle synthesis
• Optical spectroscopy

Background:

• Plasmon excitation is a powerful tool for in situ monitoring of metal nanoparticle growth.
• Existing models for optical profiles have limitations in realistically modeling particle shape due to temperature effects and broadening sources.

Purpose of the Study:

• To report on the growth of silver nanoparticles on alumina at various temperatures (190-675 K).
• To develop and validate a model for analyzing plasmonic response, considering temperature effects and finite-size impacts.

Main Methods:

• Surface differential reflectivity spectroscopy (SDRS) in the UV-visible range.
• Modeling nanoparticles as truncated spheres within the quasi-static approximation.
• Utilizing interface susceptibilities and Fresnel reflection coefficient calculations.

Main Results:

• Demonstrated the critical role of the thermal variation of the metal dielectric constant.
• Accounted for finite-size effects and introduced a convolution method for experimental broadening due to aspect ratio distribution.
• Showcased the physical meaning of parameters related to sticking probability, growth, and wetting for model validation.

Conclusions:

• The proposed modeling approach enhances the quantitative study of metal nanoparticle growth using plasmonics.
• This method offers new perspectives for understanding the growth dynamics of noble metal nanoparticles.
• Accurate modeling requires considering thermal variations and physical parameters beyond just fitting quality.