Large‐Scale Ultra‐Robust MoS₂ Patterns Directly Synthesized on Polymer Substrate for Flexible Sensing Electronics

Abstract

Synthesis of large-area patterned MoS 2 is considered the principle base for realizing high-performance MoS 2 -based flexible electronic devices. Patterning and transferring MoS 2 films to target flexible substrates, however, require conventional multi-step photolithography patterning and transferring process, despite tremendous progress in the facilitation of practical applications. Herein, an approach to directly synthesize large-scale MoS 2 patterns that combines inkjet printing and thermal annealing is reported. An optimal precursor ink is prepared that can deposit arbitrary patterns on polyimide films. By introducing a gas atmosphere of argon/hydrogen (Ar/H 2 ), thermal treatment at 350 °C enables an in situ decomposition and crystallization in the patterned precursors and, consequently, results in the formation of MoS 2 . Without complicated processes, patterned MoS 2 is obtained directly on polymer substrate, exhibiting superior mechanical flexibility and durability (≈2% variation in resistance over 10,000 bending cycles), as well as excellent chemical stability, which is attributed to the generated continuous and thin microstructures, as well as their strong adhesion with the substrate. As a step further, this approach is employed to manufacture various flexible sensing devices that are insensitive to body motions and moisture, including temperature sensors and biopotential sensing systems for real-time, continuously monitoring skin temperature, electrocardiography, and electromyography signals.

Printed Electronics Based on 2D Material Inks: Preparation, Properties, and Applications toward Memristors

“…Recently, Li et al demonstrated a novel MoS 2 inkjet printing flexible pattern by printing MoS 2 precursors, as shown in Figure 9. [142] Precursor patterns were first deposited onto flexible polyimide (PI) substrates through inkjet printing, followed by drying and thermal annealing (Figure 9a). The in situ patterns of MoS 2 were obtained on a large area of 150 mm × 150 mm flexible substrate (Figure 9b,c).…”

“…As shown in Figure 10d, the connection and disconnection of the metal filaments determine the low and high resistance states of the device (Figure 10d). [159] In addition, an ion migration/valence Small Methods 2023, 7, 2201156 [142] Copyright 2022, Wiley-VCH. Table 3.…”

“…Typical optical photographs of inkjet-printed precursor patterns (b) and annealed MoS 2 patterns (c) on PI substrates with an area of 150 mm × 150 mm under flat and rolling conditions. Reproduced with permission [142]. Copyright 2022, Wiley-VCH.…”

Recent progress in thermal management for flexible/wearable devices

“…The design and development of advanced wearable devices still pose challenges because of the need to integrate electronic, electrochemical, electro-optical, or multiple types of functionality on a platform that is soft, compact, lightweight, flexible, and stretchable [12,13] . To do so, various manufacturing technologies, such as laser processing [14][15][16][17] , transfer printing [18][19][20][21] , and inkjet printing [22][23][24][25][26] , have been used to fabricate a flexible/stretchable device platform. Ensuring long-term reliability and biocompatibility during human body motion, especially in outdoor activities involving external heat exposure and metabolic heat generation, adds to the challenges in material/structure development and device design.…”

Laser-assisted synthesis of two-dimensional transition metal dichalcogenides: a mini review

“…Flexible electronics is a disruptive science and technology based on a high degree of interdisciplinary integration, which provides novel opportunities for the development of the next generation of the information technology revolution and the era of intelligent manufacturing ( Zheng et al, 2022 ; Li et al, 2023 ). The two-dimensional materials, especially transition metal dichalcogenides have become trending research topics of flexible electronics due to their unique structure, mechanical flexibility, tunable bandgaps, and high mobility ( Mak et al, 2010 ; Fan et al, 2015 ; Kim et al, 2015 ; Leong, 2020 ; Yu et al, 2020 ; Liu et al, 2021 ; Wu et al, 2022 ).…”