MXene-tailored CNT cold cathodes and self-powered electron emitters toward plasma generation

The fabrication of carbon nanotube (CNT) field emitters usually involves a complicated process and shows poor adhesion to the substrate, which leads to inferior electron emission. Taking advantage of Ti3C2 MXene in film-forming, we have prepared CNT/MXene field emitters on various substrates. The emitter on stainless steel achieves an outstanding continuous emission density of 125 mA cm−2 and a pulse emission up to 750 mA cm−2. In addition, the arrayed CNT/MXene emitter on structured polydimethylsiloxane displays a current density of 73.9 mA cm−2 at a low field of 2.5 V µm−1, as well as good stability for 13.8 h. Meanwhile, the CNT/MXene emitter could operate when powered by a triboelectric nanogenerator, and the result indicates that CNT/MXene emitter can be used as a generator for producing plasma in air. The work opens a strategy to fabricate superior CNT cathodes on various substrates and holds great promise for practical applications in cold electron vacuum electronics and self-powered devices.