Inkjet Printing of Self‐Assembled 2D Titanium Carbide and Protein Electrodes for Stimuli‐Responsive Electromagnetic Shielding

Abstract

2D titanium carbides (MXene) possess significant characteristics including high conductivity and electromagnetic interference shielding efficiency (EMI SE) that are important for applications in printed and flexible electronics. However, MXene-based ink formulations are yet to be demonstrated for proper inkjet printing of MXene patterns. Here, tandem repeat synthetic proteins based on squid ring teeth (SRT) are employed as templates of molecular self-assembly to engineer MXene inks that can be printed as stimuli-responsive electrodes on various substrates including cellulose paper, glass, and flexible polyethylene terephthalate (PET). MXene electrodes printed on PET substrates are able to display electrical conductivity values as high as 1080 ± 175 S cm −1 , which significantly exceeds electrical conductivity values of state-of-the-art inkjet-printed electrodes composed of other 2D materials including graphene (250 S cm −1 ) and reduced graphene oxide (340 S cm −1 ). Furthermore, this high electrical conductivity is sustained under excessive bending deformation. These flexible electrodes also exhibit effective EMI SE values reaching 50 dB at films with thicknesses of 1.35 µm, which mainly originate from their high electrical conductivity and layered structure.

Ultrathin and Flexible CNTs/MXene/Cellulose Nanofibrils Composite Paper for Electromagnetic Interference Shielding

“…A novel family of 2D early transition metal carbides and/ or nitrides, MXenes (M n+1 X n T x , where M represents an early transition metal, X represents C and/or N, n = 1, 2, or 3, and T is a terminating group, such as O, OH, and/or F), were firstly discovered in 2011 by the selective etching and delamination of their layered MAX phase [15][16][17][18][19]. With large specific surface area and high electrical conductivity [20][21][22][23][24][25], Ti 3 C 2 T x MXene has recently been extensively reported as a remarkable shielding material [26][27][28][29][30][31][32][33][34][35][36][37][38][39]. For example, Gogotsi and his co-workers firstly reported a metallically conductive Ti 3 C 2 T x -based film with excellent conductivity (4665 S cm −1 ) and superior EMI shielding effectiveness (> 92 dB, 45 µm) [3].…”

Fabrication of Nonwetting Flexible Free‐Standing MXene‐Carbon Fabric for Electromagnetic Shielding in S‐Band Region

“…Thus, the presence of TiO 2 NP was furthermore reduced the passing of the electromagnetic waves. MXene film comprises basic mechanism of reflection, absorption, and multiple reflection, and scattering was an additional advantage of the fabric (Figure (d)).…”

MXene Printing and Patterned Coating for Device Applications

“…Vural et al inkjet printed Ti 3 C 2 T x MXene inks into large‐area (≈2 cm) stimuli‐responsive electrodes on various substrates including cellulose paper, glass, and flexible PET. [ 107 ] To tackle the problems of poor jetting stability, and the formation of the “coffee ring effect” that results from the low viscosity of pure MXene ink, MXene nanosheets were dispersed in a high‐viscosity solvent, i.e., DMSO with synthetic structural proteins as a binder ( Figure a). The excellent dispersion quality of the MXene suspensions was preserved by limiting the concentration of the synthetic binders to 1 mg mL −1 , a value above which instant sheet aggregation started to take place (Figure 12b).…”

“…a–g) Reproduced with permission. [ 107 ] Copyright 2018, Wiley‐VCH. h) Thickness‐dependent attenuation versus frequency obtained using different MXene waveguides.…”