Size, Composition, and Phase-Tunable Plasmonic Extinction in Au-Sn Alloy Nanoparticles

Area of Science:

• Nanotechnology
• Materials Science
• Physical Chemistry

Background:

• Tailoring nanoparticle optical properties is crucial for advanced applications.
• Controlling localized surface plasmon resonances (LSPR) in alloy nanoparticles remains a challenge.

Purpose of the Study:

• To explore the synthesis of Au-Sn nanoparticles with tunable LSPR.
• To investigate the influence of size, composition, and phase formation on LSPR.
• To provide insights into the structure-property relationships of Au-Sn nanoparticles.

Main Methods:

• Synthesis of Au-Sn nanoparticles from Au seeds (5-30 nm).
• UV-visible spectroscopy for LSPR analysis.
• X-ray diffraction (XRD) for phase identification.
• Elemental analysis (EDS, TXRF, ICP-OES) for composition.

Main Results:

• Controllable LSPR blueshifting from 520 to 460 nm with increased Sn.
• Formation of Au₅Sn and AuSn intermetallic phases, dependent on size and Sn content.
• Different phases (Au_xSn_1-x, Au₅Sn, AuSn) exhibit distinct LSPR behaviors (blueshifting, broadening, damping).

Conclusions:

• Precise control over Au-Sn nanoparticle size, structure, and optical properties is achievable.
• Understanding intermetallic phase formation impacts LSPR, enabling tailored plasmonic materials.
• This work facilitates the development of Au-Sn nanoparticles for sensing, imaging, and catalysis.