Anomalous Raman and photoluminescence blue shift in mono- and a few layered pulsed laser deposited MoS2 thin films

Pradhan, Gobinda; Sharma, Ashwini Kumar

doi:10.1016/j.materresbull.2018.03.001

Cited by 28 publications

(14 citation statements)

References 37 publications

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“…40 The slight blueshift (approximately 1 cm −1 ) of E 2g 1 and A 1g shifts attributed to the strain from lattice distortion. 41 The Raman shifts were consistent with the AFM and TEM results (Figures 1 and 2).…”

Section: ■ Results and Discussionsupporting

confidence: 87%

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Nanoholes Regulate the Phytotoxicity of Single-Layer Molybdenum Disulfide

Tong

Feng

Hou

et al. 2019

Environ. Sci. Technol.

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Single-layer molybdenum disulfide (SLMoS2) are applied as a hot 2D nanosheet in various fields involving water treatments. Both intentional design and environmental or biological processes induce many nanoholes in SLMoS2. However, the effects of nanoholes on the environmental stability and ecotoxicity of SLMoS2 remain largely unknown. The present work discovered that visible-light irradiation induced nanoholes (diameters, approximately 20 nm) in the plane of SLMoS2, with irregular edges and increased interplanar crystal spacing. The ratios of Mo to S in pristine and transformed SLMoS2 were 0.53 and 0.33, respectively. After 96 h exposure at concentrations from 0.1 to 1 mg/L, the above nanoholes promoted algal division, induced a stress-response hormesis, decreased the generation of •OH, and mitigated the cell shrinkage and wall rupture of Chlorella vulgaris induced by SLMoS2. In terms of stress response, the nanohole-bearing SLMoS2 induced fewer vacuoles and polyphosphate bodies of Chlorella vulgaris than the pristine form. Metabolomic analysis revealed that nanoholes perturbed the metabolisms of energy, carbohydrates, and fatty acids. This work proposes that nanoholes cause obvious effects on the environmental fate and ecotoxicity of SLMoS2 and that the environmental risks of engineered nanomaterials should be reevaluated using nanohole-bearing rather than pristine forms for testing.

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Section: ■ Results and Discussionsupporting

confidence: 87%

“…N-SLMoS 2 presented a higher A 1 g / E 2 g 1 ratio (2.11) than P-SLMoS 2 (2.06), supporting a greater extent of disorder . The slight blueshift (approximately 1 cm –1 ) of E 2 g 1 and A 1 g shifts attributed to the strain from lattice distortion . The Raman shifts were consistent with the AFM and TEM results (Figures and ).…”

Section: Resultssupporting

confidence: 83%

Nanoholes Regulate the Phytotoxicity of Single-Layer Molybdenum Disulfide

Tong

Feng

Hou

et al. 2019

Environ. Sci. Technol.

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“…The samples are fitted at 1.8, 2.0 and 2.2 eV, which correspond to the A-trions, A-exciton and B-exciton of MoS 2 PL emission, respectively. 21,47 The A-exciton and B-exciton are associated with the excitonic transition at the K -point of the Brillouin zone. Meanwhile, the A-trion peak was attributed to the transition resulting from charge impurities in the MoS 2 layer.…”

Section: Resultsmentioning

confidence: 99%

“…Meanwhile, the direct band gap of single or few layers thick MoS 2 exhibit a peak at 1.8-1.9 eV, which makes it a highly suitable semiconductor oxide to be activated within the visible light region [20]. Moreover, with such a narrow band gap, MoS 2 possess a rapid transfer of charge carriers along with a wide absorption in the range of visible light, making it as a promising and valuable photocatalyst candidate [20,21].…”

Section: Introductionmentioning

confidence: 99%

The improved photocatalytic activity of highly expanded MoS₂ under visible light emitting diodes

et al. 2021

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“…There, the integral ratio of E 2g /A 1g , denoted as I (E 2g )/ I (A 1g ), is always used to monitor the change of interlayer bonding as the thickness of the 2D materials is decreased. It has been found that there is a good linear relationship between the I (E 2g )/ I (A 1g ) ratio and the number of layers in few‐layered TaSe 2 , MoS 2 , and WSe 2 . It then becomes a reliable strategy to estimate the number of layers of these 2D materials, including graphene .…”

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confidence: 99%

Flexible Foil of Hybrid TaS₂/Organic Superlattice: Fabrication and Electrical Properties

Zong

Yoo

Zhang

et al. 2019

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2D transitional metal dichalcogenide (2D-TMDC) materials, as inorganic graphene analogs (IGAs), have been intensively investigated for their novel chemical and physical properties when the thickness is reduced to a few atomic layers, such as MoS 2 , WS 2 , among others. [1] Tantalum disulfide, TaS 2 , one of the TMDC materials, has attracted growing attention recently. In the bulk state, TaS 2 occupies 2H or 1T structure, which is composed of covalently bonded STaS layers. 1T-TaS 2 with Ta in octahedral coordination with S atoms exhibits semiconducting behavior, and it has a commensurate charge density wave (CCDW) phase under 180 K. Adjusted by pressure, the superconductivity of 1T-TaS 2 develops in the CCDW state and survives to very high pressure. [2][3][4] 2H-TaS 2 with Ta in trigonal prismatic coordination with S atoms exhibits metallic behaviors with CDW phase transition (T CDW = 75 K) and superconductivity (T c = 0.8 K). [5][6][7][8] The electrical conductivity of single-crystal 2H-TaS 2 can reach 6.8 × 10 4 S m −1 at room temperature. [9] When the thickness is reduced to a few layers, interesting phenomena have been found, such as gate-tunable phase transition [10] and enhanced superconductivity, [11] which are promising properties for applications like electrical oscillators, [12] fast memories, [13] hydrogen evolution catalyst. [14] Until now, 2D TaS 2 has been mainly synthesized by the mechanical exfoliation method, [15] which is time consuming and of poor reproductivity and low yield. It has been noticed that the exfoliation of TaS 2 seems rather difficult and the atomically thin layers are unstable in ambient environments due to easy oxidation. [16] Complex encapsulation techniques are therefore required to help preserve the samples in air. [16] The chemical vapor deposition method [17] proves to be swift and effective in fabrication of high-quality 2D materials, but large-area synthesis of full-coverage atomically thin material is still in progress. For device applications, solution-based chemical synthesis is particularly important, as the product can be easily integrated into electronic devices.There is a new solution-based strategy to synthesize 2D materials in the form of inorganic/organic superlattice, in which the inorganic layers may get close to the low-dimensional state due to the spatial separation by the organic molecules. In our previous papers, we synthesized a hybrid superlattice with alternating 2D [TiS 2 ] monolayers and organic cations through an electrochemical reaction process. [18] The isolation of the [TiS 2 ] TaS 2 nanolayers with reduced dimensionality show interesting physics, such as a gate-tunable phase transition and enhanced superconductivity, among others. Here, a solution-based strategy to fabricate a large-area foil of hybrid TaS 2 /organic superlattice, where [TaS 2 ] monolayers and organic molecules alternatively stack in atomic scale, is proposed. The [TaS 2 ] layers are spatially isolated with remarkably weakened interlayer bonding, resulting in lattice vibration ...

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Anomalous Raman and photoluminescence blue shift in mono- and a few layered pulsed laser deposited MoS2 thin films

Cited by 28 publications

References 37 publications

Nanoholes Regulate the Phytotoxicity of Single-Layer Molybdenum Disulfide

Nanoholes Regulate the Phytotoxicity of Single-Layer Molybdenum Disulfide

The improved photocatalytic activity of highly expanded MoS₂ under visible light emitting diodes

Flexible Foil of Hybrid TaS₂/Organic Superlattice: Fabrication and Electrical Properties

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Anomalous Raman and photoluminescence blue shift in mono- and a few layered pulsed laser deposited MoS2 thin films

Cited by 28 publications

References 37 publications

Nanoholes Regulate the Phytotoxicity of Single-Layer Molybdenum Disulfide

Nanoholes Regulate the Phytotoxicity of Single-Layer Molybdenum Disulfide

The improved photocatalytic activity of highly expanded MoS2 under visible light emitting diodes

Flexible Foil of Hybrid TaS2/Organic Superlattice: Fabrication and Electrical Properties

Contact Info

Product

Resources

About

The improved photocatalytic activity of highly expanded MoS₂ under visible light emitting diodes

Flexible Foil of Hybrid TaS₂/Organic Superlattice: Fabrication and Electrical Properties