Fully Sprayed Metal Oxide Transistors Utilizing Ti₃C₂T_x MXene Contacts

Printable large-area electronics continue to attract increasing interest from the scientific and industrial communities, owing to their potential for cost-efficient manufacturing. However, the exerted efforts primarily focus on processing semiconductors and dielectrics, with relatively limited attention toward printable electrode materials. In this respect, the family of two-dimensional (2D) transition metal carbides/nitrides, so-called MXenes, have emerged as promising electrode materials owing to their metal-like conductivity and solution processability. Despite their advantageous characteristics, however, to date, the application of MXene electrodes in the area of printed electronics has been marginally explored. Herein, we develop all-solution-processable In₂O₃/ZnO heterojunction metal oxide thin-film transistors (TFTs) utilizing Ti₃C₂T_x MXene as the gate and the electron-injecting contacts, entirely spray-coated under ambient conditions. We show that the manufacturing of these fully spray-coated devices can be scaled-up to 4 in. substrates without compromising their operating characteristics. The fabricated TFTs exhibit electron mobility of 3 cm² V^-1 s^-1 with an on/off ratio of >10⁴. Our findings demonstrate the possibility of replacing conventional metal contacts with spray-coated MXene electrodes for application in large-area electronics.