Acoustic Vibrations in Bimetallic Au@Pd Core-Shell Nanorods

Area of Science:

• Nanotechnology
• Materials Science
• Physical Chemistry

Background:

• Gold nanorods are versatile nanomaterials with tunable optical and electronic properties.
• Coating gold nanorods with other metals, like palladium, can modify their characteristics for advanced applications.
• Understanding the mechanical and vibrational properties of such bimetallic nanostructures is crucial for their design and utilization.

Purpose of the Study:

• To investigate the acoustic vibrations of gold nanorods coated with palladium.
• To correlate vibrational modes with the amount of deposited palladium.
• To develop a novel method for characterizing bimetallic nano-objects.

Main Methods:

• Ultrafast pump-probe spectroscopy was employed to excite and detect coherent acoustic vibrations.
• Both extensional and breathing vibrational modes of the gold nanorods were analyzed.
• Experimental data were compared with numerical simulations.

Main Results:

• The periods of extensional and breathing vibrational modes exhibited opposite trends with increasing palladium deposition.
• Extensional mode periods decreased, while breathing mode periods increased with palladium coating.
• These changes are attributed to alterations in nanoparticle size and mechanical properties.

Conclusions:

• The study provides a precise method to determine the amount of deposited palladium on gold nanorods.
• This technique is effective for characterizing bimetallic nano-objects, even with low fractions of palladium (down to 5% Pd/Au atomic fraction).
• The findings offer a novel tool for analyzing the composition and properties of multicomponent nanomaterials.