Enhanced and Spectrally Selective Near Infrared Photothermal Conversion in Plasmonic Nanohelices

TL;DR

This paper investigates plasmonic nanohelices made from metals like cobalt and nickel, demonstrating their highly efficient, spectrally selective near-infrared photothermal conversion with temperature rises up to 1000 K, suitable for various applications.

Contribution

It reveals the spectrally selective photothermal properties of metal nanohelices near their plasmon resonances, especially in the near-infrared range, highlighting their potential for advanced applications.

Findings

Temperature rise up to 1000 K at resonance wavelengths

Spectrally selective photothermal conversion in near-infrared

Potential applications in solar energy, desalination, catalysis, nanomedicine

Abstract

We study the photothermal conversion in plasmonic nanohelices, unveiling how helical nanostructures made from metals with a notable interband activity, such as cobalt (Co) and nickel (Ni), exhibit a remarkable temperature rise $\Delta$T up to $\approx$1000 K under illumination. Such outstanding $\Delta$T values exclusively occur at wavelengths close to their localised plasmon resonances ($\Delta$T is significantly lower off resonance), and therefore the photothermal conversion of these nanoparticles is spectrally selective. The exceptional and spectrally selective temperature rise is demonstrated at near infrared wavelengths, which prompts the use of Co and Ni helical nanoparticles in a wide range of photothermal applications including solar energy conversion, seawater desalination, catalysis, or nanomedicine.