Hyejin Jang
Seoul National University · 物理学・天文学
研究室紹介
Professor Hyejin Jang's research lab specializes in thermal transport properties of advanced two-dimensional and emerging functional materials, with a focus on understanding and engineering anisotropic thermal conductivity in materials such as black phosphorus, ReS₂, and halide perovskites. The lab employs advanced ultrafast optical techniques like time-domain thermoreflectance to probe nonequilibrium dynamics of electrons, phonons, and magnons, particularly in ultrathin films and heterostructures. A key research direction involves developing sustainable and biodegradable electronic systems using environmentally friendly materials and scalable fabrication methods. The lab also explores multifunctional, non-toxic antibiofilm coatings for long-term surface protection in biomedical and environmental applications.
Research Overview
Research Output Trend
Figures are computed from collected data and may differ slightly.
Selected Papers
15The anisotropic thermal conductivity of passivated black phosphorus (BP), a reactive two-dimensional material with strong in-plane anisotropy, is ascertained. The room-temperature thermal conductivity for three crystalline axes of exfoliated BP is measured by time-domain thermoreflectance. The thermal conductivity along the zigzag direction is ≈2.5 times higher than that of the armchair direction. Black phosphorus (BP), a stable phosphorus allotrope at ambient temperature and pressure,1 is a tw
ReS 2 represents a different class of 2D materials, which is characterized by low symmetry having 1D metallic chains within the planes and extremely weak interlayer bonding. Here, the thermal conductivity of single‐crystalline ReS 2 in a distorted 1 T phase is determined at room temperature for the in‐plane directions parallel and perpendicular to the Re‐chains, and the through‐plane direction using time‐domain thermoreflectance. ReS 2 is prepared in the form of flakes having thicknesses of 60–4
Halide perovskites have emerged as promising candidates for various applications, such as photovoltaic, optoelectronic and thermoelectric applications. The knowledge of the thermal transport of halide perovskites is essential for enhancing the device performance for these applications and improving the understanding of heat transport in complicated material systems with atomic disorders. In this work, the current understanding of the experimentally and theoretically obtained thermal transport pr
Nonequilibrium of electrons, phonons, and magnons in metals is a fundamental phenomenon in condensed-matter physics and serves as an important driver in the field of ultrafast magnetism. In this work, we demonstrate that the magnetization of a subnanometer-thick Co layer with perpendicular magnetic anisotropy can effectively serve as a thermometer to monitor nonequilibrium dynamics in adjacent metals, Pt and Ru, via time-resolved magneto-optic Kerr effect. The temperature evolutions of the Co th
Abstract The biodegradable electronics are on the rise, not just due to their role in medical implants, but also because of their eco‐friendly attributes. A variety of methods, including transfer printing, have been employed to integrate inorganic electronics onto biodegradable polymer substrates. However, the use of expensive materials, multiple intermediary steps, and labor‐intensive procedures can undermine their environment‐friendly benefits. Here, a straightforward yet efficient fabrication
In recent decades, extensive research has been directed toward mitigating microbial contamination and preventing biofilm formation. However, many conventional antibiofilm methods rely on hazardous and toxic substances, neglecting potential risks to human health and the environment. Moreover, these approaches often rely on single-strategy mechanisms, utilizing either bactericidal or fouling-resistant agents, which have shown limited efficacy in long-term biofilm suppression. In this study, we pro
Abstract Due to its small hole‐effective mass, flexibility, and transparency, copper iodide (CuI) has emerged as a promising p ‐type alternative to the predominantly used n ‐type metal oxide semiconductors. However, the lack of effective doping methods hinders the utility of CuI in various applications. Sulfur (S)‐doping through liquid iodination is previously reported to significantly enhance electrical conductivity up to 511 S cm −1 . In this paper, the underlying doping mechanism with various
This study was performed to analyze retrospectively outcomes of stimulated in vitro fertilization (IVF) cycles where the gonadotropin-releasing hormone (GnRH) antagonist was omitted on ovulation triggering day. A total of 92 consecutive IVF cycles were included in 65 women who are undergoing ovarian stimulation with recombinant FSH. A GnRH antagonist, cetrorelix 0.25 mg/day, was started when leading follicle reached 14 mm in diameter until the day of hCG administration (Group A, 66 cycles) or un
$\mathrm{Sr}\mathrm{Ru}{\mathrm{O}}_{3}$, a $p$-type metallic conductor with a small thermopower, and $\mathrm{Sr}\mathrm{Ti}{\mathrm{O}}_{3}$, a $p$-type insulator with a large thermopower in its hyperstoichiometric state, have been reported to make a complete solid solution. It is, thus, suggested that the thermoelectric power factor, conductivity times thermopower squared (\ensuremath{\sigma}\ensuremath{\theta}), may be best optimized by mixing these two extreme oxides. In order to explore th
Organic/inorganic hybrid composites are crucial in industrial applications for imparting the necessary physical properties. With the advancement of electronic components, managing heat dissipation has become vital. Research on thermal interface materials, particularly thermally conductive adhesives combining epoxy polymers, is gaining attention for their strong adhesion and thermomechanical properties. In these systems, curing agents like thiol are essential for enhancing properties due to their
Ultrathin two-dimensional (2D) transition metal dichalcogenides (TMDs) exhibit unique band structures, allowing promising thermoelectric properties. Achieving a high power factor ( PF ) for thermoelectric generators (TEGs) requires optimizing both the Seebeck coefficient ( S ) and electrical conductivity ( σ ). Conventional surface charge-transfer doping can be a solution to enhance σ by introducing additional electrons. However, residual organic dopants act as charged impurities, degrading char