Optical Properties of Triangular Molybdenum Disulfide Nanoflakes

Wendumu, Tsegabirhan Berhane; Seifert, Gotthard; Lorenz, Tommy; Joswig, Jan‐Ole; Enyashin, Andrey N.

doi:10.1021/jz501604j

Cited by 38 publications

(34 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, the number of peaks and their intensities show varying trend as the size is increased. The induced electron densities of the low-energy peaks have a substantial contribution from the edge analogously to S-terminated MoS 2 flakes [28]. In contrast, the main contribution to the prominent 3.23 eV excitation originates from the central region of the flake, in agreement with its coincidence with the absorption peak of the infinite monolayer.…”

Section: A Size-dependent Trends In the Optical Responsesupporting

confidence: 62%

“…As the flake size is increased, the spectrum starts to resemble that of the infinite monolayer with the exception that the low-energy peaks remain below the absorption onset of the monolayer. The low-energy peaks show a general redshifting trend as the flake size is increased, analogously to the low-energy peaks in S-terminated MoS 2 flakes [28]. However, the number of peaks and their intensities show varying trend as the size is increased.…”

Section: A Size-dependent Trends In the Optical Responsementioning

confidence: 65%

“…Depending on the growth conditions, the flakes favor different edge terminations or shapes [16,[25][26][27]. However, for alternative S-terminated edges, the 1D plasmons are expected to couple weaker to light [19] and they have not been reported in previous computational studies of Sterminated triangular flakes [28,29].…”

Section: Introductionmentioning

confidence: 94%

See 2 more Smart Citations

Effect of edge plasmons on the optical properties of MoS2 monolayer flakes

et al. 2017

View full text Add to dashboard Cite

Finite MoS 2 nanoparticles are known to support metallic edge states that are responsible for their catalytic activity. In this work we employ time-dependent density-functional theory (TDDFT) to study the influence of such edge states on the optical properties of triangular MoS 2 monolayer flakes. We find that the edge states support collective plasmon-like excitations that couple strongly to the optical field leading to pronounced absorption peaks below the onset of interband transitions on the basal plane. Additionally, structural relaxation of the flakes can significantly distort the edge states. Thus, we observe that while an evenly-spaced edge configuration supports one-dimensional (1D) plasmon modes similar to those of an ideal 1D electron gas, the relaxed structures show mixed plasmon and single-electron excitations in the low-energy response. Our findings illustrate the sensitivity of the optical response of MoS 2 nanostructures to the details of the edge configuration.

show abstract

Section: A Size-dependent Trends In the Optical Responsesupporting

confidence: 62%

Section: A Size-dependent Trends In the Optical Responsementioning

confidence: 65%

See 1 more Smart Citation

Effect of edge plasmons on the optical properties of MoS2 monolayer flakes

et al. 2017

View full text Add to dashboard Cite

show abstract

“…4,5,17,31 We will add some new aspects here from a very recent study of the optical absorption in such nanoflakes. 57 Figure 2 displays the calculated optical absorption spectra of triangular MoS 2 nanoflakes in the visible range of the electromagnetic spectrum. With increasing edge length, d, the absorption peaks are red-shifted, which illustrates the quantum confinement in such systems.…”

Section: Optical Excitations In Triangular Mosmentioning

confidence: 99%

Optics, Mechanics, and Energetics of Two-Dimensional MoS₂ Nanostructures from a Theoretical Perspective

et al. 2014

Self Cite

View full text Add to dashboard Cite

CONSPECTUS: Nanostructures based on molybdenum disulfide (MoS2) are by far the most common and well-studied systems among two-dimensional (2D) semiconducting materials. Although still being characterized as a "promising material", catalytic activity of MoS2 nanostructures has been found, and applications in lubrication processes are pursued. Because exfoliation techniques have improved over the past years, monolayer MoS2 is easily at hand; thus, experimental studies on its electronic properties and applicability are in scientific focus, and some MoS2-based electronic devices have been reported already. Additionally, the improvement of atomic force microscopy led to nanoindentation experiments, in which the exceptional mechanical properties of MoS2 could be confirmed. In this Account, we review recent results from density-functional based calculations on several MoS2-based nanostructures; we have chosen to follow several experimental routes focusing on different nanostructures and their specific properties. MoS2-based triangular nanoflakes are systems that are experimentally well described and studied with a special focus on their optical absorption. The interpretation of our calculations fits well to the experimental picture: the absorption peaks in the visible light range show a quantum-confinement effect; they originate from excitations into the edge states. Additionally, delocalized metallic-like states are present close to the Fermi level, which do not contribute to photoabsorption in the visible range. Additionally, nanoindentation experiments have been simulated to obtain mechanical properties of the MoS2 material and to study the influence of deformation on the system's electronics. In these molecular-dynamics simulations, a tip penetrates a MoS2 monolayer, and the obtained Young's modulus and breaking stress agree very well with experimentally obtained values. Whereas the structural properties, such as bond lengths and layer contraction, vary locally differently upon indentation, the electronic structure in terms of the density of states, the gap between occupied and unoccupied states, or the quantum transport change only slightly. The robustness of the material with respect to electronic and mechanical properties makes monolayer MoS2 special. However, it is important to note that this robustness refers to a local disturbance through deformation and still seems to be dependent on the defect concentration. Finally, we present a comparison of the thermodynamic stabilities of different MoS2-based nanostructures with a focus on nanoflakes, fullerene-like nanooctahedra, and smaller Chevrel-type and non-Chevrel-type clusters (nanowires). All studied systems are stable in comparison to MoS2, Mo bulk, and the S8 crown, but only the studied nanoflakes and nanowires show specific stoichiometries, either sulfur-rich or sulfur-poor, whereas the nanooctahedra may adopt both. From the thermodynamic stabilities, it should be possible to deliberately choose specific nanostructures by thoughtful choices of the synthesis c...

show abstract

“…The self‐consistent density‐functional tight‐binding (SCC‐DFTB) method is developed and is attracting attentions more than ever since it can give reasonable accuracy results at a remarkably reduced computational cost . It has already been successfully used in the studies of nano‐system properties related to biological and nanomedicine applications . The SCC‐DFTB method is extended to the time‐dependent density‐functional based tight‐binding method (TD‐DFTB) to study the optical properties of large systems .…”

Section: Introductionmentioning

confidence: 99%

Density‐functional theory study of the interaction mechanism and optical properties of flavonols on the boron nitride nanotubes

Fan

Zhu

2017

Int J of Quantum Chemistry

View full text Add to dashboard Cite

The flavonols are natural pigments with multiple colors. They are found ubiquitously in plants and are relevant to flower colors and the UV protection in plants. Their antioxidant, anticancer, and anti‐allergic features attract researchers much attention to explore their potential applications in biological and nanomedical areas. In this study, the interaction mechanism and optical properties of four representative flavonols, on both the surface and confined in the single‐walled boron nitride nanotubes (BNNTs), have been explored comparatively by self‐consistent density‐functional based tight‐binding method (SCC‐DFTB) and density‐functional theory (DFT). The results indicate a stronger binding when flavonols are confined inside the BNNTs. The influence of mutual interaction between flavonols and BNNTs on the excited properties and UV/vis feature of the complex structure was studied by time‐dependent DFT. Due to the interaction of flavonols with BNNTs and the weakness of the intramolecular hydrogen bond, our results indicate a red‐shift of the flavonol spectra when they are outside or inside the tube. The study concludes that the properties of flavonols can be fine‐tuned by the interaction with BNNTs.

show abstract

Optical Properties of Triangular Molybdenum Disulfide Nanoflakes

Cited by 38 publications

References 22 publications

Effect of edge plasmons on the optical properties of MoS2 monolayer flakes

Effect of edge plasmons on the optical properties of MoS2 monolayer flakes

Optics, Mechanics, and Energetics of Two-Dimensional MoS₂ Nanostructures from a Theoretical Perspective

Density‐functional theory study of the interaction mechanism and optical properties of flavonols on the boron nitride nanotubes

Contact Info

Product

Resources

About

Optical Properties of Triangular Molybdenum Disulfide Nanoflakes

Cited by 38 publications

References 22 publications

Effect of edge plasmons on the optical properties of MoS2 monolayer flakes

Effect of edge plasmons on the optical properties of MoS2 monolayer flakes

Optics, Mechanics, and Energetics of Two-Dimensional MoS2 Nanostructures from a Theoretical Perspective

Density‐functional theory study of the interaction mechanism and optical properties of flavonols on the boron nitride nanotubes

Contact Info

Product

Resources

About

Optics, Mechanics, and Energetics of Two-Dimensional MoS₂ Nanostructures from a Theoretical Perspective