Large-Area MXene Electrode Array for Flexible Electronics

Abstract

MXenes, an emerging class of two-dimensional (2D) transition metal carbides and nitrides, have potential for application as high-performance, low-cost electrodes in organic field-effect transistors (OFETs) because of their water dispersibility, high conductivity, and work-function tunability. In this study, we successfully fabricated a large-scale, uniform Ti3C2T x MXene electrode array on a flexible plastic substrate for application in high-performance OFETs. The work function of the Ti3C2T x MXene electrodes was also effectively modulated via chemical doping with NH3. The fabricated OFETs with Ti3C2T x MXene electrodes exhibited excellent device performance, such as a maximum carrier mobility of ∼1 cm2·V–1·s–1 and an on–off current ratio of ∼107 for both p-type and n-type OFETs, even though all the electrode and dielectric layers were fabricated on the plastic substrate by solution processing. Furthermore, MXene-electrode-based complementary logic circuits, such as NOT, NAND, and NOR, were fabricated via integration of p-type and n-type OFETs. The proposed approach is expected to expand the application range of MXenes to other OFET-based electronic devices, such as organic light-emitting displays and electronic skins.

2D Transition Metal Carbides (MXenes): Applications as an Electrically Conducting Material

“…[79] The high electrical conductivity of Ti 3 C 2 T x MXene is extremely useful for electrodes in field-effect transistors (FETs). [118][119][120][121] Zhang et al reported spin-coated transparent Ti 3 C 2 T x MXene films with different thicknesses (t) and corresponding transmittances (T) by controlling the spinning speed and concentration of the MXene solution (Figure 5a-d). [32] The transmittance of the films decreases with an increase in the MXene thickness (from 93% at 4 nm thickness to 29% at 88 nm) (Figure 5e).…”

“…f) Output characteristics and h) transfer characteristics of n-type PTCDI-C8 OFETs with NH 3 -doped MXene (NMX) electrodes. a-h) Reproduced with permission [121]. Copyright 2019, American Chemical Society.…”

2D MXene–TiO2 Core–Shell Nanosheets as a Data‐Storage Medium in Memory Devices

“…MXenes are a class of 2D metal carbides, carbonitrides, or nitrides that have an elementary structure composed of 2–5 layers of early transition metals intercalated by carbon and/or nitrogen layers; they have been attracting increasing research attention because of their excellent physical and chemical properties such as metallic conductivity, [ 1 ] water dispersibility, [ 2 ] high optical transparency (>97% per nm), [ 3 ] tunable work function, [ 4,5 ] electromagnetic interference (EMI) shielding effect, [ 6 ] photothermal effect, [ 7 ] good mechanical properties, [ 8 ] and antibacterial activity. [ 9 ] Since the discovery of Ti 3 C 2 T x MXene by Gogotsi's group in 2011, this MXene and its derivatives have demonstrated outstanding performance in various applications, such as energy storage, electronics, EMI shielding, sensors, water purification, and desalination.…”

Organic Semiconductor Field-Effect Transistors Based on Organic-2D Heterostructures

“…Except for graphene (Di et al, 2008), MXene also shows great potential. Cho and coworkers employed two-dimensional Ti 3 C 2 T x MXene as electrodes to realize a high-performance OFETs array with both p-type and n-type OSCs, and flexible complementary logic circuits, such as NOT, NAND, and NOR, were fabricated via integration of p-type and n-type OFETs (Figures 6A,B; Lyu et al, 2019). In this work, the MXene not only exhibited its capability of acting as a highly conductive flexible electrode, but also played a crucial role in improving OFETs performance by lowering the carrier injection barrier.…”

“…The strategies to optimize the electronic structure of the conductive channel of OFETs devices presented in the above work can be summarized in the following manner: (i) employing 2D material nanosheets to construct charge transport pathways with higher conducting efficiency in the bulk of OSC layers (Liscio et al, 2011;Lyuleeva et al, 2018); (ii) establishing ambipolar OSC/2D hybrid FETs with parallel layers of OSC and 2D materials respectively working as n-type or p-type conductive channels (He X. et al, 2017;Yan et al, 2018); (iii) reducing the contact barriers between OSC channels and electrodes with proper 2D materials as source/drain electrodes (Di et al, 2008;Lyu et al, 2019). In addition, interface charge transfer doping between OSC and 2D layers is also of great potential to optimize the channel electronic structure and improve the OFETs performances.…”