Automatic Fast Friction Preparation of Gallium-Based Liquid Metal Transparent Conductive Films

Transparent conductive films (TCFs) are the core functional layer of rigid electronic devices, whose preparation simplicity and performance stability directly impact downstream industrial costs. The mainstream indium tin oxide (ITO) is limited by scarce resources and high-energy preparation, while gallium-based liquid metals with room-temperature liquidity and high conductivity are potential alternatives. However, their high surface tension causes droplet agglomeration during film formation, hampering uniform transparent films and practical use. To address this bottleneck, this study proposes friction printing via an automated biaxial platform: integrating a polished quartz rod and precisely regulating friction speed enabled uniform gallium-based film deposition on glass, solving agglomeration. Subsequent 400 °C oxygen annealing converted opaque films into gallium-based transparent conductive (GBTC) films. Tests show annealed Galinstan oxide films perform best: visible transmittance >80%, sheet resistance ∼160 Ω/□, and X band (8.2–12.4 GHz) shielding efficiency ∼30 dB, meeting low-end and even some high-end rigid electronic needs. Further experiments demonstrate the transparent films’ electromagnetic shielding performances and patterned heating effects. This fast and low-cost approach breaks barriers of film formation, clarifies annealing’s modulation mechanism, offers a route for high-performance gallium-based film design and scaling, and has broad prospects in transparent electromagnetic shielding windows and stable sensors.