Photothermal nonlinearity in plasmon-assisted photocatalysis.

Area of Science:

• Nanophotonics and Plasmonics
• Materials Science
• Photocatalysis

Background:

• Understanding the interplay between light and heat in metallic nanoparticles is vital for plasmon-enhanced processes.
• Previous research indicated host thermal conductivity dominates temperature rise in nanoparticle ensembles.
• Photocatalysis and other light-driven reactions are sensitive to temperature variations.

Purpose of the Study:

• To investigate the influence of host thermal conductivity's temperature dependence on the nonlinear photothermal response of metallic nanoparticle systems.
• To explain experimental observations in plasmon-assisted photocatalysis using the proposed photothermal nonlinearity.
• To assess the contribution of thermal emission to photothermal nonlinearity.

Main Methods:

• Theoretical analysis of photothermal effects in metallic nanoparticle ensembles.
• Modeling the temperature dependence of host thermal conductivity.
• Comparison of theoretical predictions with experimental data from photocatalysis studies.

Main Results:

• The temperature dependence of host thermal conductivity leads to a strongly sublinear temperature rise, often exceeding tens of percent.
• This photothermal nonlinearity can explain experimental outcomes in plasmon-assisted photocatalysis.
• Thermal emission can also contribute to photothermal nonlinearity under specific conditions.

Conclusions:

• The nonlinear photothermal response is primarily governed by the host material's thermal conductivity.
• This mechanism must be considered before attributing plasmon-assisted photocatalysis effects to non-thermal electrons.
• Accurate modeling of photothermal effects is crucial for understanding light-matter interactions in nanomaterials.