MXene-Contacted Carbon Nanotube Thin-Film Transistors Using Aerosol Jet Printing

MXenes have garnered significant attention for electronics applications due to their facile synthesis, tunable properties, and exceptional optical and electrical characteristics. Their stable aqueous suspension without additional surfactants enables compatibility of MXenes with various low-cost, additive manufacturing techniques, including spin coating, spraying, and direct-write printing. In this work, we investigate the aerosol jet printing of water-based Ti₃C₂T_x MXene on surfaces with different wettability, achieving printed thin films with sheet resistance as low as ∼7 Ω/□ within three printing passes on both hydrophilic and hydrophobic substrates. Furthermore, we present MXene-contacted carbon nanotube thin-film transistors (CNT-TFTs) with various device geometries, finding a tradeoff between on- and off-state performance when selecting between bottom and top contacts, respectively. Devices with MXene contacts exhibited performance (on-state current up to 16.9 μA/mm and on/off-current ratio of 10⁶) comparable to printed CNT-TFTs contacted by graphene and silver nanowires; meanwhile, the lower unit price of MXene ink makes it a more attractive candidate for low-cost, large-area fabrication.