Characterizing core-shell nanostructures through photoacoustic response based on theoretical model in the frequency...

Area of Science:

• Nanotechnology
• Materials Science
• Acoustics

Background:

• Core-shell nanostructures are crucial for various applications, but their photoacoustic (PA) properties are not fully understood due to indirect theoretical models.
• Existing theoretical models primarily focus on the time domain, limiting a comprehensive understanding of the relationship between structural parameters and PA spectral characteristics.

Purpose of the Study:

• To develop a complete theoretical model in the frequency domain for analyzing the photoacoustic response of core-shell particles.
• To investigate the influence of structural parameters, such as shell thickness and core radius, on the photoacoustic modes of core-shell nanostructures.

Main Methods:

• Development of a novel frequency-domain theoretical model for core-shell particle photoacoustic response.
• Analysis of resonant modes and their dependence on core radius and shell thickness.
• Validation of the model using gold-silica nanospheres under single-pulse irradiation, comparing results with time-domain theories and experimental data.

Main Results:

• Core-shell particles exhibit pronounced resonant modes, similar to solid spheres.
• The photoacoustic mode is directly influenced by the shell thickness and core radius.
• Under multi-pulse irradiation, PA signal magnitude peaks when excitation frequency or its harmonic matches the PA mode, allowing for structural monitoring.

Conclusions:

• The developed frequency-domain model provides a comprehensive understanding of core-shell nanostructure photoacoustic properties.
• The findings demonstrate that structural parameters significantly dictate photoacoustic modes.
• This research enriches photoacoustic theory and offers potential for new noninvasive nanoparticle characterization techniques.