Seon Joon Kim

Achieving high sensitivity in solid-state gas sensors can allow the precise detection of chemical agents. In particular, detection of volatile organic compounds (VOCs) at the parts per billion (ppb) level is critical for the early diagnosis of diseases. To obtain high sensitivity, two requirements need to be simultaneously satisfied: (i) low electrical noise and (ii) strong signal, which existing sensor materials cannot meet. Here, we demonstrate that 2D metal carbide MXenes, which possess high

Miniaturization of electronics demands electromagnetic interference (EMI) shielding of nanoscale dimension. The authors report a systematic exploration of EMI shielding behavior of 2D Ti₃ C₂ T_x MXene assembled films over a broad range of film thicknesses, monolayer by monolayer. Theoretical models are used to explain the shielding mechanism below skin depth, where multiple reflection becomes significant, along with the surface reflection and bulk absorption of el

Abstract The main gas‐sensing mechanisms of 2D materials are surface charge transfer by analytes and Schottky barrier (SB) modulation at the interface between the metallic and semiconducting surfaces. In particular, dramatic differences in the gas‐sensing performances of 2D materials originate from SB modulation. However, SB sites typically exist only at the interface between the semiconducting channel material and the metal electrode. Herein, in situ formed multiple SBs in a single gas‐sensing

MXenes are a prominent family of two-dimensional materials because of their metallic conductivity and abundant surface functionalities. Although MXenes have been extensively studied as bulk particles or free-standing films, thin and transparent films are needed for optical, optoelectronic, sensing, and other applications. In this study, we demonstrate a facile method to fabricate ultrathin (∼10 nm), Ti₃C₂T_<i>x</i> MXene films by an interfacial assembly technique.

MXenes have recently attracted significant interest owing to their outstanding properties and performance. However, their hydrophilic and metastable surfaces make most MXenes prone to oxidation, which can greatly degrade their properties and hinder their practical applications. Here, we enhanced the stability of Ti3C2Tx MXene films by coating a continuous zeolitic imidazolate framework-8 (ZIF-8) layer. The high-density oxygen functional groups of MXene, which are crucial for inducing the nucleat

Developing a methodology to enhance long-term stability is one of the most important issues in MXene research, since they are prone to oxidation in the ambient environment. Although various approaches have been suggested to improve the stability of MXene, they have suffered from complicated processes and limited applicability to various types of MXene nanostructures. Herein, we report a simple and versatile technique to enhance the environmental stability of MXenes. Ti₃C₂T<

Abstract The positive effects of a lithiophilic substrate on the electrochemical performance of lithium metal anodes are confirmed in several reports, while the understanding of lithiophilic substrate‐guided lithium metal nucleation and growth behavior is still insufficient. In this study, the effect of a lithiophilic surface on lithium metal nucleation and growth behaviors is investigated using a large‐area Ti 3 C 2 T x MXene substrate with a large number of oxygen and fluorine dual heteroatoms

Among the various factors required for membranes in organic solvent separations, the stability of membrane supports is critical in the preparation of membranes with universal chemical stability, mechanical flexibility, and high flux. In this study, nanoporous freestanding carbon nanotube (CNT) films were fabricated and utilized as supports for enhanced permeation in organic solvents. The excellent chemical stability of the CNT support allowed it to withstand various organic solvents such as tolu

High conductivity and transparency and sheet-like two-dimensional morphology of MXenes make them attractive for use as functional transparent thin films. In addition, because of the dense surface functional groups and negative surface charge of the MXene sheet, cationic species can be easily intercalated into MXene interlayers to largely enhance the film properties and device performance. In this paper, for the first time, we demonstrate a spontaneous self-assembly method to efficiently intercal

• MXene/MOF hybrid nanosheets composed of ZIF-8 and ZIF-67 were synthesized in solvents. • Gradient-structured MXene/MOF/CNT hybrid films with inversely varied concentrations of MXene/MOF and CNT were fabricated. • Gradient-structured films showed good EMI shielding properties (40 dB) and EM wave absorption (42 %) at the Ka-band. • EMI shielding and absorption was achieved through dielectric loss, interfacial polarization, and multiple scattering. Increasing reliance on wireless electronic devic

In this study, a novel buckled structure of edge-oriented MoS2 films is fabricated for the first time by employing monolayer graphene as the substrate for MoS2 film growth. Compared to typical buckling methods, our technique has several advantages: (1) external forces such as heat and mechanical strain are not applied; (2) uniform and controllable buckling over a large area is possible; and (3) films are able to be transferred to a desired substrate. Dual MoS2 orientation was observed in the buc

Abstract MXenes are a promising class of two‐dimensional transition metal carbides, nitrides, and carbonitrides, widely utilized in diverse fields such as energy storage, electromagnetic shielding, electrocatalysis, and sensing applications. Their potential in chemical sensing is particularly noteworthy, where optimizing surface chemistry for strong interaction with target analytes and increasing surface area for efficient gas adsorption are crucial factors. In this study, a versatile and genera