MXene Printing and Patterned Coating for Device Applications

Abstract

As a thriving member of the 2D nanomaterials family, MXenes, i.e., transition metal carbides, nitrides, and carbonitrides, exhibit outstanding electrochemical, electronic, optical, and mechanical properties. They have been exploited in many applications including energy storage, electronics, optoelectronics, biomedicine, sensors, and catalysis. Compared to other 2D materials, MXenes possess a unique set of properties such as high metallic conductivity, excellent dispersion quality, negative surface charge, and hydrophilicity, making them particularly suitable as inks for printing applications. Printing and pre/post-patterned coating methods represent a whole range of simple, economically efficient, versatile, and eco-friendly manufacturing techniques for devices based on MXenes. Moreover, printing can allow for complex 3D architectures and multifunctionality that are highly required in various applications. By means of printing and patterned coating, the performance and application range of MXenes can be dramatically increased through careful patterning in three dimensions; thus, printing/ coating is not only a device fabrication tool but also an enabling tool for new applications as well as for industrialization.devices. This is because solution processes such as liquid-phase exfoliation is crucial for the dispersion formation and mass production, as well as for the postsynthesis treatments on the 2D nanosheets such as sorting in terms of flake size and thickness, functionalization, compositing, etc., all of which are crucial for the ink formulation process required by printing. [6] Printed electronics technology has acquired considerable interest from both academia and industry recently. [7][8][9] Unlike traditional methods such as vacuum deposition and photolithography, printing technologies hold great promise for fast, high-volume, and low-cost manufacturing, especially for the fabrication of flexible devices. [10][11][12][13][14][15] The combination of 2D materials with printing started as early as 2012 when liquid-phase-exfoliated graphene dispersion was inkjet-printed to fabricate field-effect transistors. [16] It has since progressed from directly using the unoptimized dispersion obtained from the solution processing as inks to making formulated inks targeted toward specific printing methods and target applications (e.g., conductive tracks, transparent electrodes, transistors, photodetectors, energy storage devices such as supercapacitors, batteries, sensors, etc.). [17][18][19][20][21] As a new member to the 2D nanomaterials family, transition metal carbides, nitrides, and carbonitrides, also known as MXenes, possess outstanding electrochemical, electronic, optical, and mechanical properties, and thus have shown great promise in applications including energy storage, electronics, optoelectronics, biomedicine, sensors, and catalysis. [22][23][24][25] Research on MXenes dates back to 2011 when single-layered titanium carbide Ti 3 C 2 was synthesized and separated for the first time, [26] and has since evol...

Flexible Electronics: Status, Challenges and Opportunities

“…Metal oxides like indium tin oxide and fluorine-doped tin oxide are vastly utilized for optoelectronic applications due to their transparency and conductivity, however they offer limited flexibility due to their brittle nature (Jin et al, 2018). Thin layers of nanomaterials like graphene, carbon nanotubes, silver nanowires, and Ti 3 C 2 (MXene), as well as conductive polymers like PEDOT:PSS have been fabricated through solution processing techniques and have demonstrated favorable Young's modulus while maintaining high degrees of transparency, thus becoming a viable alternative for printed optoelectronic devices (Gao, 2017;Kim et al, 2017;Kim and Alshareef, 2020;Zhang et al, 2020). In terms of interconnections, there has been a huge demonstration of metallic nanoparticles that have been dispersed in many solvents to produce printable inks for the fabrication of conductive tracks and patterns.…”

MXene hydrogels: fundamentals and applications

“…MXenes have the general advantages of 2D materials including ultrathin structures, large specific surface area, and mechanical robustness. [7][8][9][10] However, MXenes possess several other properties that make them particularly attractive as reinforcements for hydrogels, providing a plethora of multi-responsive functionalities.…”

“…The negatively charged MXene surfaces associated with the abundant hydrophilic terminal moieties along with intercalated cations, increase the capacity of MXenes to interact with water molecules in a hydrogel network. 8,9,14 With such rich surface chemistry, MXenes not only exhibit excellent electrical conductivity but also have a large number of free charge carriers, i.e., larger than that of other 2D materials, 50 that can interact with the incident electromagnetic (EM) waves and reflect part of them before being absorbed. 47 However, the local dipoles originating from the abundant surface functional groups were found to help with the absorption of the unreflected EM waves.…”

“…Among the existing 2D nanomaterials, the thriving family of transition metal carbides, nitrides, or carbonitrides (MXenes) stand out for their unique combination of metallic conductivity, solution processability, high-aspect-ratio, and widely tunable properties. [7][8][9][10] Generally, MXenes have the chemical formula M n+1 X n T x (n = 1-4), where M and X stand for early transition metals (e.g., Ti, V, Nb, Mo, etc. ), and carbon and/or nitrogen, respectively.…”

“…Thus far, MXenes have already demonstrated very good performance in a gamut of applications spanning energy storage, sensing, optoelectronics, catalysis, and biomedicine. 7,[11][12][13] Furthermore, concerning hydrogel-based applications, MXenes are of particular interest owing to their excellent mechanical strength, 14 exceptional hydrophilicity, 8,15 and rich surface chemistry that provides another level of versatility. 10 Thus, when MXenes are incorporated in hydrogel systems, they bring about both improved properties and exciting novel functionalities for enhanced performances in various applications.…”