Selecting High-Performance Gold Nanorods for Photothermal Conversion

Area of Science:

• Nanotechnology
• Materials Science
• Biomedical Engineering

Background:

• Photothermal applications rely on metallic nanostructures for efficient light absorption and heat generation.
• Optimizing nanostructure design is crucial for maximizing photothermal conversion efficiency.

Purpose of the Study:

• Establish a new paradigm for identifying optimal arbitrarily shaped metallic nanostructures for photothermal applications.
• Appraise crucial thermo-optical parameters governing plasmonic heating.
• Explore nanoparticle size-dependence for optimization.

Main Methods:

• Investigated thermo-optical parameters influencing plasmonic heating.
• Employed a nanoparticle size-dependence approach.
• Evaluated gold nanorods as a case study for infrared photothermal conversion in water.

Main Results:

• Identified two distinct figures of merit (FoM) for optimizing metallic nanoheaters under femtosecond and continuum laser excitation.
• Found efficient photothermal conversion for small-volume gold nanorods under femtosecond pulses.
• Determined optimal gold nanorod dimensions for continuous wave excitation: 90 × 25 nm (800 nm) and 150 × 30 nm (1064 nm).
• Observed up to 700% FoM variations for structures with the same peak wavelength.

Conclusions:

• Quantifying FoM enables rational design of high-performance plasmonic nanoparticles for localized photothermal applications.
• The study provides a framework for optimizing nanostructure design based on specific excitation conditions and desired outcomes.