Ultrafast Thermometry of Gold Nanoparticles: Resolving Particle and Medium Temperature Dynamics via Transient...

Area of Science:

• Nanotechnology
• Physical Chemistry
• Spectroscopy

Background:

• Metal nanoparticles exhibit localized heating upon ultrafast pulsed illumination.
• Plasmon resonance enables spatiotemporal temperature control for various applications.
• Understanding nanoparticle and medium temperature dynamics is crucial for optimizing these processes.

Purpose of the Study:

• To propose and validate experimental methods for time-resolved measurement of particle and medium temperatures.
• To investigate the heating dynamics of gold nanoparticles in different media.
• To establish a methodology for simultaneous temperature determination under transient heating.

Main Methods:

• Utilized transient absorption spectroscopy to probe gold nanoparticles (23.5 and 39 nm) in water and DMF:water mixtures.
• Developed methods to disentangle particle and medium temperature contributions from absorbance spectra.
• Performed consistency checks between independent measurement approaches.

Main Results:

• Demonstrated simultaneous determination of particle and medium temperatures with high temporal resolution.
• Observed significant particle heating (~80 K) and moderate medium heating (5-15 K) under specific excitation conditions.
• Correlated temperature decay rates with particle size and medium thermal diffusivity.

Conclusions:

• The proposed methodology accurately determines simultaneous particle and medium temperatures under spatiotemporal gradients.
• This technique is valuable for studying transient heating phenomena involving nanoparticles.
• The findings support the use of nanoparticles as sensors in dynamic thermal environments.