Nanoconfined water vapour as a probe to evaluate plasmonic heating

Area of Science:

• Nanotechnology
• Materials Science
• Physical Chemistry

Background:

• Plasmonic materials enable photothermal effects crucial for applications like cancer therapy and chemical synthesis.
• Accurate nanoscale temperature evaluation is challenging, often requiring complex equipment and sensitive probes.
• Existing methods for measuring plasmonic heating are limited in simplicity and accessibility.

Purpose of the Study:

• To introduce a straightforward method for evaluating local temperatures around plasmonic nanoparticles.
• To utilize water vapor as a sensitive probe for nanoscale thermal effects.
• To demonstrate the feasibility of this technique on a plasmonic colloidal film with nanoporosity.

Main Methods:

• Employing water vapor to probe local heating around plasmonic nanoparticles.
• Exploiting liquid-vapor phase transitions of water within a nanoporous medium.
• Utilizing spectroscopic ellipsometry to analyze structural and optical changes in the film.
• Triggering phase transitions with external stimuli like heating or irradiation.

Main Results:

• Demonstrated the concept on a bi-modal nanoporous plasmonic colloidal film.
• Observed structural and optical variations in the film due to water phase transitions.
• Successfully estimated local temperatures using spectroscopic ellipsometry data.
• Validated water vapor as an effective nanoscale temperature probe.

Conclusions:

• The proposed method offers a simple and general approach for determining local temperatures.
• It requires only a nanoporous material and water vapor (e.g., environmental humidity).
• The technique is adaptable to various materials, vapor molecules, and optical methods for broader applicability.