Author
Agnieszka Kuc
Other affiliations: Leipzig University, Dresden University of Technology, Jacobs University Bremen ...read more
Bio: Agnieszka Kuc is an academic researcher from Helmholtz-Zentrum Dresden-Rossendorf. The author has contributed to research in topics: Band gap & Exciton. The author has an hindex of 40, co-authored 104 publications receiving 5773 citations. Previous affiliations of Agnieszka Kuc include Leipzig University & Dresden University of Technology.
Papers published on a yearly basis
Papers
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TL;DR: In this article, it was shown that quantum confinement in layered d-electron dichalcogenides results in tuning the electronic structure at the nanoscale, and the properties of related TmS2 nanolayers (Tm = W, Nb, Re) were studied.
Abstract: Bulk MoS2, a prototypical layered transition-metal dichalcogenide, is an indirect band gap semiconductor. Reducing its size to a monolayer, MoS2 undergoes a transition to the direct band semiconductor. We support this experimental observation by first principles calculations and show that quantum confinement in layered d-electron dichalcogenides results in tuning the electronic structure at the nanoscale. We further studied the properties of related TmS2 nanolayers (Tm = W, Nb, Re) and show that the isotopological WS2 exhibits similar electronic properties, while NbS2 and ReS2 remain metallic independent on size.
1,532 citations
TL;DR: In this article, the nonequlibrium Green's functions method combined with the Landauer-Buttiker approach for ballistic transport together with the density-functional-based tight binding method was used for conductance calculations on mechanically deformed monolayers of MoS and WS.
Abstract: Quantum conductance calculations on the mechanically deformed monolayers of MoS${}_{2}$ and WS${}_{2}$ were performed using the nonequlibrium Green's functions method combined with the Landauer-B\"uttiker approach for ballistic transport together with the density-functional-based tight binding method. Tensile strain causes significant changes in the electronic structure of transition-metal dichalcogenide single layers and eventually the semiconductor-metal transition occurs for elongations as large as 11$%$ for the 2D-isotropic deformations in the hexagonal structure. This transition enhances the electron transport in otherwise semiconducting materials.
270 citations
TL;DR: The stacking orders in layered hexagonal boron nitride bulk and bilayers are studied using high-level ab initio theory and it is shown that both electrostatic and London dispersion interactions are responsible for interlayer distance and stacking order, with AA' being the most stable one.
Abstract: The stacking orders in layered hexagonal boron nitride bulk and bilayers are studied using high-level ab initio theory [local second-order M\o{}ller-Plesset perturbation theory (LMP2)]. Our results show that both electrostatic and London dispersion interactions are responsible for interlayer distance and stacking order, with $A{A}^{\ensuremath{'}}$ being the most stable one. The minimum energy sliding path includes only the $A{A}^{\ensuremath{'}}$ high-symmetry stacking, and the energy barrier is 3.4 meV per atom for the bilayer. State-of-the-art density functionals with and without London dispersion correction fail to correctly describe the interlayer energies with the exception of a Perdew-Burke-Ernzerhof functional intended for solid state and surface systems that agrees very well with our LMP2 results and experiment.
255 citations
TL;DR: It is shown that the stacking of 2D COFs are considerably more stable if their stacking arrangement is either serrated or inclined, and layers are shifted with respect to each other by ~1.4 Å compared with perfect AA stacking.
Abstract: Covalent-Organic Frameworks (COFs) are a new family of 2D and 3D highly porous and crystalline materials built of light elements, such as boron, oxygen and carbon. For all 2D COFs, an AA stacking arrangement has been reported on the basis of experimental powder XRD patterns, with the exception of COF-1 (AB stacking). In this work, we show that the stacking of 2D COFs is different as originally suggested: COF-1, COF-5, COF-6 and COF-8 are considerably more stable if their stacking arrangement is either serrated or inclined, and layers are shifted with respect to each other by ∼1.4 A compared with perfect AA stacking. These structures are in agreement with to date experimental data, including the XRD patterns, and lead to a larger surface area and stronger polarisation of the pore surface.
182 citations
TL;DR: How valleytronics is possible in these materials by selective interaction of electrons in the different valleys using polarized light is discussed, and for some structures semiconductor-metal transitions could be possible.
Abstract: Transition-metal dichalcogenides TX2 (T = W, Mo; X = S, Se, Te) are layered materials that are available in ultrathin forms such as mono-, bi- and multilayers, which are commonly known as two-dimensional materials. They have an intrinsic band gap in the range of some 500 meV to 2 eV, depending on the composition and number of layers, and giant intrinsic spin–orbit splittings for odd layer numbers, and, in conjunction with their high chemical and mechanical stability, they qualify as candidate materials for two-dimensional flexible electronics and spintronics. The electronic structure of each TX2 material is very sensitive to external factors, in particular towards electric and magnetic fields. A perpendicular electric field reduces the band gap, and for some structures semiconductor–metal transitions could be possible. Moreover, the electric field triggers the spin–orbit splitting for bilayers. A magnetic field applied normal to the layers causes the Hall effect, which in some cases may result in a quantum (spin) Hall effect and thus in magnetic switches. Finally, we discuss how valleytronics is possible in these materials by selective interaction of electrons in the different valleys using polarized light.
177 citations
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28 Jul 2005
TL;DR: PfPMP1）与感染红细胞、树突状组胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作�ly.
Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。
18,940 citations
TL;DR: This work reviews the historical development of Transition metal dichalcogenides, methods for preparing atomically thin layers, their electronic and optical properties, and prospects for future advances in electronics and optoelectronics.
Abstract: Single-layer metal dichalcogenides are two-dimensional semiconductors that present strong potential for electronic and sensing applications complementary to that of graphene.
13,348 citations
TL;DR: This Review describes how the tunable electronic structure of TMDs makes them attractive for a variety of applications, as well as electrically active materials in opto-electronics.
Abstract: Ultrathin two-dimensional nanosheets of layered transition metal dichalcogenides (TMDs) are fundamentally and technologically intriguing. In contrast to the graphene sheet, they are chemically versatile. Mono- or few-layered TMDs - obtained either through exfoliation of bulk materials or bottom-up syntheses - are direct-gap semiconductors whose bandgap energy, as well as carrier type (n- or p-type), varies between compounds depending on their composition, structure and dimensionality. In this Review, we describe how the tunable electronic structure of TMDs makes them attractive for a variety of applications. They have been investigated as chemically active electrocatalysts for hydrogen evolution and hydrosulfurization, as well as electrically active materials in opto-electronics. Their morphologies and properties are also useful for energy storage applications such as electrodes for Li-ion batteries and supercapacitors.
7,903 citations
TL;DR: This critical review starts with a brief introduction to gas separation and purification based on selective adsorption, followed by a review of gas selective adsorbents in rigid and flexible MOFs, and primary relationships between adsorptive properties and framework features are analyzed.
Abstract: Adsorptive separation is very important in industry. Generally, the process uses porous solid materials such as zeolites, activated carbons, or silica gels as adsorbents. With an ever increasing need for a more efficient, energy-saving, and environmentally benign procedure for gas separation, adsorbents with tailored structures and tunable surface properties must be found. Metal–organic frameworks (MOFs), constructed by metal-containing nodes connected by organic bridges, are such a new type of porous materials. They are promising candidates as adsorbents for gas separations due to their large surface areas, adjustable pore sizes and controllable properties, as well as acceptable thermal stability. This critical review starts with a brief introduction to gas separation and purification based on selective adsorption, followed by a review of gas selective adsorption in rigid and flexible MOFs. Based on possible mechanisms, selective adsorptions observed in MOFs are classified, and primary relationships between adsorption properties and framework features are analyzed. As a specific example of tailor-made MOFs, mesh-adjustable molecular sieves are emphasized and the underlying working mechanism elucidated. In addition to the experimental aspect, theoretical investigations from adsorption equilibrium to diffusion dynamics via molecular simulations are also briefly reviewed. Furthermore, gas separations in MOFs, including the molecular sieving effect, kinetic separation, the quantum sieving effect for H2/D2 separation, and MOF-based membranes are also summarized (227 references).
7,186 citations
TL;DR: Ultraensitive monolayer MoS2 phototransistors with improved device mobility and ON current are demonstrated, showing important potential for applications in MoS 2-based integrated optoelectronic circuits, light sensing, biomedical imaging, video recording and spectroscopy.
Abstract: A very sensitive photodector based on molybdenum disulphide with potential for integrated optoelectronic circuits, light sensing, biomedical imaging, video recording or spectroscopy is now demonstrated.
4,212 citations