Large-area potassium-doped highly conductive graphene films for electromagnetic interference shielding

Area of Science:

• Materials Science
• Condensed Matter Physics

Background:

• Graphene films (GF) possess excellent mechanical and electrical properties but suffer from low carrier density, limiting their electrical conductivity.
• Improving the electrical conductivity of graphene is crucial for expanding its functional applications.

Purpose of the Study:

• To develop a post-doping method for enhancing the electrical conductivity of large-area graphene films.
• To investigate the effects of potassium doping on the properties of graphene films.

Main Methods:

• A post-doping method was employed to create potassium-doped graphene films (GF-K).
• Doping concentration was optimized to achieve stage-2 GF-K (C24K).
• Electrical conductivity and electromagnetic interference (EMI) shielding effectiveness were measured.

Main Results:

• Potassium doping increased carrier density without degrading electronic quality, achieving conductivity of 1.49 × 10^7 S m^-1.
• GF-K exhibited superior specific electrical conductivity compared to copper.
• EMI shielding effectiveness increased from 70-85 dB for GF to over 130 dB for GF-K at 31 μm thickness.

Conclusions:

• Potassium-doped graphene films (GF-K) demonstrate significantly enhanced electrical conductivity and EMI shielding performance.
• The combination of high conductivity, flexibility, and lightweight makes GF-K suitable for high-end EMI applications in aerospace and wearables.