https://scholarworks.bwise.kr/hanyang/handle/2021.sw.hanyang/173 2026-04-04T12:53:25Z 2026-04-04T12:53:25Z Umrao, Sima Shin, Hwansoo Jeong, Woojae Ko, Hwayoung Song, Sangwon Ngo, Ken A. Uzarski, Joshua R. Han, Tae Hee https://scholarworks.bwise.kr/hanyang/handle/2021.sw.hanyang/210409 2026-01-30T02:30:40Z 2026-03-01T00:00:00Z

Title: Fluoroalcohol-functionalized MXene for improved detection of sarin simulant Authors: Umrao, Sima; Shin, Hwansoo; Jeong, Woojae; Ko, Hwayoung; Song, Sangwon; Ngo, Ken A.; Uzarski, Joshua R.; Han, Tae Hee Abstract: Accurate and rapid detection of liquid-phase chemical warfare nerve agents (CWAs) such as Sarin remains a critical priority in environmental and defense applications. Two-dimensional MXenes comprising transition-metal carbides and nitrides have emerged as promising chemoresistive sensing materials owing to their metallic electronic properties and high density of pendant surface species. However, pristine MXenes exhibit limited specificity and adsorption capacity for effective organophosphates (OPs) detection. This study introduces diazonium hexafluoroisopropyl alcohol (HFIPA)-functionalized MXene (DHMX) for label-free electrochemical sensing of the Sarin simulant, dimethyl methylphosphonate (DMMP). The –(CF<inf>3</inf>)<inf>2</inf>C–OH moieties anchored on the MXene surface formed directional hydrogen bonds with the phosphoryl groups of DMMP, enabling enhanced molecular recognition. Owing to the synergistic effect of high surface area and tailored binding sites, DHMX exhibits significantly low detection limit (LOD = 0.012 pM), broad linear detection ranges (0.1–6 pM and 0.01 nM–1 µM), and high sensitivity (∼490 µA nM−1 cm−2), and outperforms pristine MXene (LOD ∼40 pM; sensitivity ∼165.9 µA nM−1 cm−2). This study presents the potential of surface-functionalized MXenes as a high-performance platform for liquid-phase electrochemical sensing of hazardous OPs.

2026-03-01T00:00:00Z Jung, Yeju Do, Kwanghyun Kim, Minjoong Choi, Minwoo Bansal, Neetu Salunkhe, Rahul R. Ahn, Heejoon https://scholarworks.bwise.kr/hanyang/handle/2021.sw.hanyang/210401 2026-01-21T04:30:21Z 2026-03-01T00:00:00Z

Title: Dispersion optimization of Si nanoparticles in Si@SiOC composites via ascorbic acid for high-performance Si-based Li-Ion batteries Authors: Jung, Yeju; Do, Kwanghyun; Kim, Minjoong; Choi, Minwoo; Bansal, Neetu; Salunkhe, Rahul R.; Ahn, Heejoon Abstract: Silicon is a promising anode material for lithium-ion batteries (LIBs) owing to its high theoretical capacity, but its practical application is hindered by low electrical conductivity and large volume expansion during cycling. Silicon oxycarbide (SiOC) serves as an effective buffering matrix for embedding Si nanoparticles (NPs); however, uncontrolled aggregation of Si NPs still induces structural degradation and limits cyclability. In this study, ascorbic acid (AA) was introduced as a dispersing agent to achieve uniform Si NP dispersion within the SiOC matrix. The improved dispersion effectively mitigated localized stress and suppressed SEI overgrowth, thereby preserving structural integrity during cycling. In addition, the incorporation of AA promoted the formation of free carbon domains (FCDs) during pyrolysis, enhancing the electronic conductivity of the composite. As a result, the optimized Si@SiOC-A5.0 electrode delivered a high initial capacity of 1057 mA h g−1 and maintained 93.3 % capacity retention after 200 cycles. This work demonstrates that controlling Si NP dispersion through AA-assisted synthesis is an effective and scalable strategy for improving the electrochemical stability and durability of Si-based composite anodes.

2026-03-01T00:00:00Z Jeong, Woojae Kang, Dong-Jun Lee, Junho Ko, Hwayoung Han, Tae Hee Sung, Jaeuk https://scholarworks.bwise.kr/hanyang/handle/2021.sw.hanyang/210454 2026-02-02T06:31:13Z 2026-02-01T00:00:00Z

Title: FWCNT-templated carbon fibers from a high carbonization yield, solution-processable p-phenylene Authors: Jeong, Woojae; Kang, Dong-Jun; Lee, Junho; Ko, Hwayoung; Han, Tae Hee; Sung, Jaeuk Abstract: Current carbon fiber manufacturing relies heavily on polyacrylonitrile (PAN) precursors, which suffer from energy-intensive processing and limited carbon yields (∼50 %). Here, we demonstrated a solution-processable poly(benzophenone) (PBP) precursor system that bypasses oxidative stabilization while achieving exceptional carbonization yields of 74 % at 1000 °C. The rigid-rod aromatic structure of PBP provides thermodynamic favorability toward graphitic transformation, while benzophenone linkages enable solubility in aprotic solvents for continuous wet-spinning. Strategic incorporation of few-walled carbon nanotubes (FWCNTs) at 0.25–1.0 wt % creates a templated carbonization pathway through non-covalent π-π interactions between aromatic polymer chains and nanotube sidewalls. This FWCNT-guided structural evolution enhances graphitic ordering (ID/IG ratio changed from 0.89 to 0.71), promotes anisotropic carbon domain growth, and delivers concurrent improvements in mechanical, electrical, and thermal properties. Optimized PBP precursor with 1 wt % FWCNT (P-CNT-1.00) derived carbon fibers achieved tensile strength of 397 MPa, Young's modulus of 93 GPa, electrical conductivity of 207 S cm−1, and thermal conductivity of 19.5 W m−1 K−1, which represents a 1.3, 3.4, 1.7, and 4.8-fold improvements over pristine PBP, respectively. This molecularly engineered approach demonstrates the feasibility of solvent processable aromatic polymer as a practical carbon fiber precursor that not only shows higher carbonization yield and energy efficiency, but also can be further enhanced via FWCNT incorporation.

2026-02-01T00:00:00Z Jeong, Bumho Kim, Hakjun Lee, Cheongbeom Park, Hansol Kim, Jieon Kim, Kyeounghak Park, Hui Joon https://scholarworks.bwise.kr/hanyang/handle/2021.sw.hanyang/209864 2026-02-05T03:00:38Z 2026-02-01T00:00:00Z

Title: Template-assisted crystallization for tin halide perovskite transistors Authors: Jeong, Bumho; Kim, Hakjun; Lee, Cheongbeom; Park, Hansol; Kim, Jieon; Kim, Kyeounghak; Park, Hui Joon Abstract: Tin (Sn) halide perovskites are promising lead-free semiconductors for next-generation electronics, yet their susceptibility to oxidation, rapid crystallization, and high defect densities hinder their application in high-performance thin-film transistors (TFTs). Here, we present a template-assisted crystallization strategy that enables two-dimensional (2D) metal halide perovskite TFTs—valued for their stability but intrinsically limited by poor charge transport—to achieve performance compatible to that of high-performance three-dimensional (3D) perovskite TFTs. Confinement within periodic nanograting grooves simultaneously enhances crystallinity—thereby suppressing trap formation—and induces near-surface compressive lattice strain that lowers the carrier effective mass. The resulting TFTs achieve a record-high field-effect mobility of 24.08 cm2V−1s−1 among 2D Sn halide perovskites, with on/off ratios exceeding 107, a subthreshold swing of 0.95 V dec−1, and minimal hysteresis. The devices exhibit exceptional operational stability under cyclic bias, prolonged bias stress, and dynamic switching, as well as prolonged air and thermal stability. This work establishes nanoscale crystallization control as a powerful approach for unlocking the performance and stability potential of lead-free perovskite electronics.

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