Ultrathin Metal Film on Graphene for Percolation-Threshold-Limited Thermal Emissivity Control.

Area of Science:

• Materials Science
• Nanotechnology
• Optics

Background:

• Controlling thermal emission is crucial for various technological applications.
• Graphene's unique properties offer potential for modifying material optical and thermal characteristics.

Purpose of the Study:

• To investigate the effectiveness of translucent gold/graphene hybrid films in reducing thermal emission.
• To determine the impact of graphene on the critical gold deposition thickness and optical properties.

Main Methods:

• Fabrication of gold/graphene hybrid films with varying gold deposition thicknesses on silicon substrates.
• Characterization of optical properties (absorptivity) and thermal emission.
• Evaluation of film stability under high temperatures and mechanical strain.

Main Results:

• A significant reduction in critical gold deposition thickness for emissivity change was observed with graphene (8.5 nm vs. 15 nm).
• Graphene incorporation drastically increased infrared absorptivity with minimal impact on visible absorptivity.
• The hybrid films demonstrated stable thermal emission performance up to 300 °C and 4% mechanical strain.

Conclusions:

• Gold/graphene hybrid films are effective for thermal emission reduction, especially near the gold percolation threshold.
• Graphene facilitates the formation of a thin, crystalline gold layer, lowering the critical thickness.
• These films offer a versatile platform for thermal management, including anti-counterfeiting applications.