A 2D Titanium Carbide MXene Flexible Electrode for High‐Efficiency Light‐Emitting Diodes

Abstract

Although several transparent conducting materials such as carbon nanotubes, graphene, and conducting polymers have been intensively explored as flexible electrodes in optoelectronic devices, their insufficient electrical conductivity, low work function, and complicated electrode fabrication processes have limited their practical use. Herein, a 2D titanium carbide (Ti3C2) MXene film with transparent conducting electrode (TCE) properties, including high electrical conductivity (≈11 670 S cm−1) and high work function (≈5.1 eV), which are achieved by combining a simple solution processing with modulation of surface composition, is described. A chemical neutralization strategy of a conducting‐polymer hole‐injection layer is used to prevent detrimental surface oxidation and resulting degradation of the electrode film. Use of the MXene electrode in an organic light‐emitting diode leads to a current efficiency of ≈102.0 cd A−1 and an external quantum efficiency of ≈28.5% ph/el, which agree well with the theoretical maximum values from optical simulations. The results demonstrate the strong potential of MXene as a solution‐processable electrode in optoelectronic devices and provide a guideline for use of MXenes as TCEs in low‐cost flexible optoelectronic devices.

Improving oxidation stability of 2D MXenes: synthesis, storage media, and conditions

“…MXenes have attracted significant attention owing to their versatile intrinsic properties, such as an excellent metallic conductivity that originates from excess electron density at the Fermi level ( E F ) [ 9 ], hydrophilicity due to abundant water-loving polar surface terminations [ 10 ], and easy solution processability without any need of dispersing agents [ 11 ]. These unique properties render them favorable in various potential applications such as electromagnetic interference (EMI) shielding [ 12 – 15 ], terahertz shielding [ 16 , 17 ], electrochemical energy storage [ 18 – 20 ], optoelectronics [ 21 , 22 ], flexible and transparent electrodes [ 23 , 24 ], sensors [ 25 ], thermal heaters [ 26 ], light-emitting diodes (LEDs) [ 27 , 28 ], and antibacterial films [ 29 ].…”

Engineering Aggregation‐Resistant MXene Nanosheets As Highly Conductive and Stable Inks for All‐Printed Electronics

“…Transition metal carbides and nitrides with 2D layered morphologies, known as MXenes, constitute an intriguing new addition to the constellation of 2D materials owing to their excellent levels of mechanical strength and metallic conductivity, and due to the hydrophilicity of their surfaces. [3][4][5] MXenes constitute a large family of compounds and can be represented by the formula M n+1 X n T x (n = 1-4), where M stands for an early transition metal (Sc, Ti, Zr, Cr, etc. ), X denotes nitrogen or carbon, and T x represents terminal F, O, or OH functional groups on the basal surfaces of the MXenes.…”

Strain Engineering in 2D Material‐Based Flexible Optoelectronics

“…In addition to the 2D active layers with excellent performance, TCE with sufficient electrical conductivity is also very important in the fabrication of flexible LEDs. Soyeong et al [122] fabricated a single-layered Ti 3 C 2 -based LEDs with solutionprocessable MXene as electrodes (Figure 11m). Due to high electrical conductivity and high work function (5.1 eV) of MXene, the Ti 3 C 2 -based LEDs present high performance with a current efficiency of 102.0 cd A −1 , a power efficiency of 103.7 lm W −1 , and a EQE of 28.5% ph/el, approaching the theoretical maxima of this device structure.…”