The performance of printed electronics is largely dictated by the nature of the ink materials and the printing process. Atomically thin 2D semiconductors [7][8][9][10][11][12][13][14] have emerged as potential ink materials for solution-processable van der Waals (vdW) thin films with few interfacial traps, ideally suited for highperformance and ultrathin printed electronics. However, currently printed 2D semiconductor devices are still limited by their unsatisfactory electronic properties, thick semiconductor layers, and large pattern dimensions (millimeter scale), [4,[15][16][17][18][19] primarily due to the difficulty of highprecision printing of ultrathin continuous patterns with low void ratios, especially single-layer or double-layer continuous and uniformly flat stacking, and lowquality nanosheets with a rather broad thickness distribution and interfacial impurities/trapping states between grain boundaries, [15][16][17][19][20][21][22] thus making it difficult to achieve highly compact thin films with optimum vdW interfaces essential for excellent electron transport and ultrathin structures. Additionally, most 2D material inks use highboiling-point solvents, such as N,N-dimethylformamide (DMF) and N-methyl-2-pyrrolidone (NMP), assisted by additional surfactants. [23] In contrast, 2D materials have lower boiling points and toxicity in alternative solvents without additional surfactants, such as water, acetone, isopropyl alcohol (IPA), and ethanol, often making it difficult to achieve robust and uniform 2D semiconductor crystals offer the opportunity to further extend Moore's law to the atomic scale. For practical and low-cost electronic applications, directly printing devices on substrates is advantageous compared to conventional microfabrication techniques that utilize expensive photolithography, etching, and vacuum-metallization processes. However, the currently printed 2D transistors are plagued by unsatisfactory electrical performance, thick semiconductor layers, and low device density. Herein, a facile and scalable 2D semiconductor printing strategy is demonstrated utilizing the interface capture effect and hyperdispersed 2D nanosheet ink to fabricate high-quality and atomic-thick semiconductor thin-film arrays without additional surfactants. Printed robust thin-film transistors using 2D semiconductors (e.g., MoS 2 ) and 2D conductive electrodes (e.g., graphene) exhibit high electrical performance, including a carrier mobility of up to 6.7 cm 2 V −1 s −1 and an on/off ratio of 2 × 10 6 at 25 °C. As a proof of concept, 2D transistors are printed with a density of ≈47 000 devices per square centimeter. In addition, this method can be applied to many other 2D materials, such as NbSe 2 , Bi 2 Se 3 , and black phosphorus, for printing diverse high-quality thin films. Thus, the strategy of printable 2D thin-film transistors provides a scalable pathway for the facile manufacturing of high-performance electronics at an affordable cost.
