Towards graphane field emitters

Ding, Shuyi; Cole, Matthew T.; Li, Chi; Zhou, Yecheng; Collins, Clare M.; Kang, Man-Su; Parmee, Richard; Lei, Wei; Zhang, Xiaobing; Dai, Qing; Milne, W. I.; Wang, Baoping

doi:10.1039/c5ra20771a

Cited by 8 publications

(3 citation statements)

References 67 publications

(84 reference statements)

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“…This is because hydrogen atoms donate electrons to the structure, shifting the Fermi level by up to 0.25 eV. Similar results have been reported in the experimental literature, where the work function of hydrogenated carbon is decreased [27,28].…”

Section: Work Function Of Defective Graphenesupporting

confidence: 87%

Tailoring the work function of graphene via defects, nitrogen-doping and hydrogenation: A first principles study

Dimov¹,

Staykov²,

Kusdhany‬³

et al. 2023

Nanotechnology

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The effect of defects, nitrogen doping, and hydrogen saturation on the work function of graphene is investigated via first principle calculations. Whilst Stone–Wales defects have little effect, single and double vacancy defects increase the work function by decreasing charge density in the π-electron system. Substitutional nitrogen doping in defect-free graphene significantly decreases the work function, because the nitrogen atoms donate electrons to the π-electron system. In the presence of defects, these competing effects mean that higher nitrogen content is required to achieve similar reduction in work function as for crystalline graphene. Doping with pyridinic nitrogen atoms at vacancies slightly increases the work function, since pyridinic nitrogen does not contribute electrons to the π-electron system. Meanwhile, hydrogen saturation of the pyridinic nitrogen atoms significantly reduces the work function, due to a shift from pyridinic to graphitic-type behavior. These findings clearly explain some of the experimental work functions obtained for carbon and nitrogen-doped carbon materials in the literature, and has implications in applications such as photocatalysis, photovoltaics, electrochemistry, and electron field emission.

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Section: Work Function Of Defective Graphenesupporting

confidence: 87%

Tailoring the work function of graphene via defects, nitrogen-doping and hydrogenation: A first principles study

Dimov¹,

Staykov²,

Kusdhany‬³

et al. 2023

Nanotechnology

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“…To confirm the SEM observation of no damage on the steel substrate, profiler scans were taken and interferograms were constructed which are presented in Supplemental Information Figure S3 . In stark contrast, other state of the art GO based coatings were observed to show significant wear in the range of 1–30 × 10 −6 mm 3 /N m 25 , 33 , 34 on the discs. The estimated Archard wear rate for the respective counterface balls in both ambient and dry N 2 conditions shown in Fig.…”

Section: Resultsmentioning

confidence: 77%

“…On the other hand, layer level encapsulation/composites have also been demonstrated to be equally effective. Zhang et al 25 have demonstrated the lowering of friction by developing a hybrid MoS 2 –rGO structure via chemical synthesis route. Friction recorded against a metal matrix composite with the hybrid lubricant and commercial alumina ceramic ball was in the range of 0.21–0.35 over a broad range of temperatures.…”

Section: Introductionmentioning

confidence: 99%

Towards developing robust solid lubricant operable in multifarious environments

Ayyagari

Mutyala

Sumant

2020

Sci Rep

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Conventional solid lubricants such as MoS2, graphite, or diamond-like carbon films demonstrate excellent tribological performance but only in specific environments due to their inherent materials properties. This limitation prohibits using these solid lubricants in environments that change dynamically. This study presents the results of a novel solid lubricant that was developed using a combination of solution-processed 2D-molybdenum disulfide and graphene-oxide (GO) that can be deposited on to stainless steel substrates using a simple spray-coating technique and show exceptional performance in multifarious environments namely, ambient (humid) atmosphere, dry nitrogen, and vacuum. The tribological performance of the coatings was evaluated using a ball-on-disc sliding test and demonstrated an excellent wear/friction performance in all environments and coating survived even after 44 km of linear sliding. Transmission electron microscopy and Raman spectroscopy analysis of the tribolayers suggested in-operando friction-induced re-orientation of MoS2 layers that were protected by GO layers and, an absence of MoOx peaks indicate a strong resistance to intercalation with moisture and oxygen. The simplicity and robustness of the hybrid MoS2–GO solid lubricant in mitigating wear-friction behavior of steel-on-steel tribopair in a multifarious environment is a game-changing and is promising for various applications.

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