High-Performance Field Emission of Free-Standing Carbon Nanotube Films Prepared via Electrophoresis

Carbon nanotubes (CNTs), owing to their high aspect ratio and excellent electrical conductivity, are promising candidates for field electron emission (FE) applications. Fabricating them into free-standing carbon nanotube films, also known as buckypapers, can significantly enhance emission current and operational stability. However, conventional fabrication methods such as vacuum filtration suffer from limitations including nonuniform deposition, prolonged processing time, and residual impurities, which restrict their large-scale application in FE devices. In this work, we propose an efficient electrophoretic deposition (EPD) approach to fabricate uniform, mechanically robust, and thickness-tunable (3–50 μm) single-walled carbon nanotube (SWCNT) buckypapers and systematically evaluate their field emission characteristics. The EPD-derived films exhibit smooth and dense morphology, reduced impurity and defect content, and excellent mechanical strength. The 3 μm-thick free-standing film achieves an ultralow turn-on field of 0.81 V/μm and delivers a remarkably high current density of 18.4 A/cm2 at 1.52 V/μm. Annealing at 450 °C further enhances FE performance, yielding a maximum current density of 122.8 A/cm2. The EPD-fabricated SWCNT buckypapers exhibit exceptional performance, high processing efficiency, and remarkable structural stability, highlighting their significant potential for flexible vacuum microelectronic applications.