Thermodynamically induced in Situ and Tunable Cu Plasmonic Behaviour

Area of Science:

• Materials Science
• Nanotechnology
• Optics

Background:

• Copper nanoparticles (Cu NPs) are crucial for plasmonic applications.
• Controlling NP size and distribution is key to tuning optical properties.
• Glass matrices offer a stable platform for embedding NPs.

Purpose of the Study:

• To investigate the synthesis of Cu NPs in a soda-lime glass matrix.
• To study the effect of thermal annealing on Cu NP size and plasmonic behavior.
• To analyze the thermodynamic mechanisms governing Cu NP growth.

Main Methods:

• Cu⁺ ↔ Na⁺ ion exchange followed by thermal annealing.
• Optical absorption spectroscopy to study localized surface plasmon resonance (SPR).
• High-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDX), grazing incidence X-ray diffraction (GIXRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and secondary ion mass spectrometry (SIMS) for structural and chemical analysis.

Main Results:

• Tunable localized surface plasmon resonance (SPR) observed with a blue shift from 570 to 560 nm as temperature increased from 550 to 650°C.
• A relationship between Cu NP size, SPR, and full width half maxima (FWHM) was established.
• Crystalline nature of Cu NPs confirmed, along with their embedding within the glass matrix.
• Thermodynamic parameters (enthalpy, entropy, Gibbs free energy) elucidated the in situ thermal growth mechanism.

Conclusions:

• The study successfully synthesized size-tunable Cu NPs in a glass matrix via ion exchange and annealing.
• Thermal annealing provides control over Cu NP size, influencing SPR and optical properties.
• Thermodynamic analysis offers insights into the growth mechanism and efficient NP distribution.