Raman studies of MoS2 at high pressure

Bagnall, A.G.; Liang, W. Y.; Marseglia, E.; Welber, B.

doi:10.1016/0378-4363(80)90257-0

Cited by 75 publications

(58 citation statements)

References 7 publications

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“…As the annealing temperature is elevated, blueshift of the A 1 g peak was observed, while E 1 2g peak did not show any appreciable change (Figure a,b). It is previously reported that the peak shift of A 1 g is related to the number of MoS 2 layers; when the number of stacked layers decreases, atom vibration is activated by the decrease of van der Waals force between the layers, resulting in the redshift of A 1 g signal . Based on the trend observed in the frequency of Raman peaks, we confirm the number of MoS 2 layers increased as thermal annealing temperature was elevated (Figure c).…”

Section: Resultssupporting

confidence: 83%

Edge‐Terminated MoS₂ Nanoassembled Electrocatalyst via In Situ Hybridization with 3D Carbon Network

Chung

Yoo

Park

et al. 2018

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Transition metal dichalcogenides, especially MoS , are considered as promising electrocatalysts for hydrogen evolution reaction (HER). Since the physicochemical properties of MoS and electrode morphology are highly sensitive factor for HER performance, designed synthesis is highly pursued. Here, an in situ method to prepare a 3D carbon/MoS hybrid catalyst, motivated by the graphene ribbon synthesis process, is reported. By rational design strategies, the hybrid electrocatalysts with cross-connected porous structure are obtained, and they show a high HER activity even comparable to the state-of-the-art MoS catalyst without appreciable activity loss in long-term operations. Based on various physicochemical techniques, it is demonstrated that the synthetic procedure can effectively guide the formation of active site and 3D structure with a distinctive feature; increased exposure of active sites by decreased domain size and intrinsically high activity through controlling the number of stacking layers. Moreover, the importance of structural properties of the MoS -based catalysts is verified by controlled experiments, validating the effectiveness of the designed synthesis approach.

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Section: Resultssupporting

confidence: 83%

Edge‐Terminated MoS₂ Nanoassembled Electrocatalyst via In Situ Hybridization with 3D Carbon Network

Chung

Yoo

Park

et al. 2018

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“…It has been reported that the A 1g peak redshifted by 4 cm −1 and FWHM broadened by 6 cm −1 with an electron doping of 1.8 × 10 13 /cm 2 due to increased electronphonon interactions, [38] although interlayer interactions could as well cause the shift by changing the restoring force. [39] On the other hand, the E 1 2g peak has been shown to redshift with increasing strain or interlayer van der Waals force. [34,35] Position and FWHM changes of the E 1 2g and A 1g peaks upon annealing are summarized in Figure 3.…”

Section: Methodsmentioning

confidence: 99%

Changes in the Raman spectra of monolayer MoS₂ upon thermal annealing

Kim

Jung

et al. 2018

J Raman Spectroscopy

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Defects have crucial effects on the electronic and optoelectronic properties of two‐dimensional materials. In this work, we measured the changes in the Raman spectra and electrical conductance of monolayer molybdenum disulfide (MoS2) with increasing defects via thermal annealing in a reducing atmosphere. Raman spectra of the basal plane MoS2 on SiO2 differed from those of the edge and revealed intricate changes upon annealing up to 550°C due to the substitution of adsorbed molecules and the creation of highly concentrated defects. On the other hand, MoS2 on hexagonal boron nitride (h‐BN) presented homogenous Raman spectra over the entire area and showed no noticeable changes in its Raman spectra upon annealing. For MoS2 on h‐BN, the charge transfer between MoS2 and adsorbed molecules and the number of defects created by annealing up to 550°C are not sufficient to change the Raman spectra. The distinct behaviors of the two sample spectra are ascribed to different substrate‐induced doping and interfacial adhesion strengths.

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“…There are usually slight differences between frequencies of Raman lines in all [35] studies, including this study. Besides common calibration/ equipment differences, first and second-order Raman lines have been shown to undergo slight shifts due to differences in temperature [17], pressure [22], and crystal size [23,24], all of which are possible explanations for these variations in reported wavenumbers.…”

Section: Raman Spectroscopy Of Mosmentioning

confidence: 99%

A Raman Spectroscopic Study of MoS2 and MoO3: Applications to Tribological Systems

2011

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Molybdenum disulfide (MoS 2 ) and molybdenum trioxide are investigated using Raman spectroscopy with emphasis on the application to tribological systems. The Raman vibrational modes were investigated for excitation wavelengths at 632.8 and 488 nm using both micro-crystalline MoS 2 powder and natural MoS 2 crystals. Differences are noted in the Raman spectra for these two different wavelengths, which are attributed to resonance effects due to overlap of the 632.8 nm source with electronic absorption bands. In addition, significant laser intensity effects are found that result in laser-induced transformation of MoS 2 to MoO 3 . Finally, the transformation to molybdenum trioxide is explored as a function of temperature and atmosphere, revealing an apparent transformation at 375 K in the presence of oxygen. Overall, Raman spectroscopy is an useful tool for tribological study of MoS 2 coatings, including the role of molybdenum trioxide transformations, although careful attention must be given to the laser excitation parameters (both wavelength and intensity) when interpreting Raman spectra.

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Raman studies of MoS2 at high pressure

Cited by 75 publications

References 7 publications

Edge‐Terminated MoS₂ Nanoassembled Electrocatalyst via In Situ Hybridization with 3D Carbon Network

Edge‐Terminated MoS₂ Nanoassembled Electrocatalyst via In Situ Hybridization with 3D Carbon Network

Changes in the Raman spectra of monolayer MoS₂ upon thermal annealing

A Raman Spectroscopic Study of MoS2 and MoO3: Applications to Tribological Systems

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Raman studies of MoS2 at high pressure

Cited by 75 publications

References 7 publications

Edge‐Terminated MoS2 Nanoassembled Electrocatalyst via In Situ Hybridization with 3D Carbon Network

Edge‐Terminated MoS2 Nanoassembled Electrocatalyst via In Situ Hybridization with 3D Carbon Network

Changes in the Raman spectra of monolayer MoS2 upon thermal annealing

A Raman Spectroscopic Study of MoS2 and MoO3: Applications to Tribological Systems

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Product

Resources

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Edge‐Terminated MoS₂ Nanoassembled Electrocatalyst via In Situ Hybridization with 3D Carbon Network

Edge‐Terminated MoS₂ Nanoassembled Electrocatalyst via In Situ Hybridization with 3D Carbon Network

Changes in the Raman spectra of monolayer MoS₂ upon thermal annealing