Deep-UV Plasmonics with Stable In2Au Alloy (Blue Gold) Nanoparticles

Area of Science:

• Nanotechnology
• Materials Science
• Plasmonics

Background:

• Surface plasmon resonances (SPRs) in nanoparticles are crucial for studying material properties and enhancing local electric fields.
• Conventional noble metal nanoparticles lack SPRs below 400 nm, limiting applications in the deep ultraviolet (UV) spectrum.

Purpose of the Study:

• To fabricate and characterize novel alloy nanoparticles with deep UV plasmon resonances.
• To explore the potential of these nanoparticles for advanced applications.

Main Methods:

• Fabrication of surfactant-free indium-gold (In2Au) nanoparticles (5-10 nm).
• Characterization of crystalline and chemical structure using ensemble-averaged and single-particle techniques.
• Machine-learning assisted analysis of scanning transmission electron microscopy-electron energy loss spectroscopy (STEM-EELS) data.

Main Results:

• Successfully synthesized In2Au nanoparticles exhibiting metallic properties and high crystallinity in the blue gold structure.
• Demonstrated plasmon resonances extending into the deep UV range, down to 280 nm.
• Machine learning enabled precise separation of plasmonic signals from background noise and identification of chemical phases in individual nanoparticles.

Conclusions:

• In2Au nanoparticles offer a new platform for creating tailored UV-plasmonic nanostructures.
• The ability to measure plasmonic signals in <10 nm particles advances nanoalloy nano-optics.
• These findings open avenues for applications in photocatalysis, biosensing, and hot carrier generation.