Study on adsorption and desorption of ammonia on graphene

Zhang, Zhengwei; Zhang, Xinfang; Luo, Wenhua; Yang, Hang; He, Yan-Lan; Liu, Yixing; Zhang, Xueao; Peng, Gang

doi:10.1186/s11671-015-1060-7

Cited by 49 publications

(40 citation statements)

References 24 publications

(33 reference statements)

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“…The position of SPR dip in transmission spectrum depends upon many factors such as size, shape of AuNC and dielectric constant of the surrounding material. The position observed in the present case is similar to the earlier observed SPR position by Zhang et al . for Au/graphene structure.…”

Section: Resultssupporting

confidence: 92%

Au concentration‐dependent quenching of Raman 2D peak in graphene

Ranjan

Tulika²,

Laha

et al. 2017

J Raman Spectroscopy

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We investigate the effect of sputtered gold nanoclusters (AuNCs) on the Raman spectra of graphene. The two prominent Raman peaks of graphene – 2D and G – show drastically different behaviour with AuNC introduction. The Raman 2D peak intensity decreases with gold coverage and finally is quenched for moderate gold nanoparticle coverage, while the G peak shows a AuNC size‐dependent enhancement in peak intensity. The quenching of the 2D peak is attributed to the hybridization of graphene's 2pz orbital with the 5d orbitals of Au. The G peak enhancement is due to the surface‐enhanced Raman scattering induced by the surface plasmons created in the AuNC by the incident laser beam (He–Ne laser, wavelength = 632.8 nm). The existence of surface plasmons is independently confirmed by UV‐visible spectrophotometry measurements. Copyright © 2017 John Wiley & Sons, Ltd.

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Section: Resultssupporting

confidence: 92%

Au concentration‐dependent quenching of Raman 2D peak in graphene

Ranjan

Tulika²,

Laha

et al. 2017

J Raman Spectroscopy

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“…Past efforts include using dielectric spacers, made with SiO 2 and Al 2 O 3 of controlled thickness, as well as graphene . The existing fabrication techniques to realize these strategies often involves multi‐step microfabrication processes involving expensive patterning techniques such as e‐beam lithography, nano‐sphere lithography, nanoimprint lithography or vacuum based deposition techniques.…”

Section: Introductionmentioning

confidence: 99%

Directed Microwave‐Assisted Self‐Assembly of Au–Graphene–Au Plasmonic Dimers for SERS Applications

Ghosh

Paria

Balasubramanian

et al. 2019

Adv Materials Inter

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photodetection [5,6] and photocatalysis. [7] While random aggregates of silver nano particles can result in very high enhance ment, thereby facilitating the detection of single molecules through Raman scat tering; [8] for technological applications, a greater control and reproducibility over the junction dimensions and therefore enhancements will be necessary. Past efforts include using dielectric spacers, made with SiO 2 [9,10] and Al 2 O 3 [11] of con trolled thickness, as well as graphene. [5,[12][13][14] The existing fabrication techniques to realize these strategies often involves multi step microfabrication processes involving expensive patterning techniques such as ebeam lithography, [15,16] nanosphere lithography, [17] nanoimprint lithography [18] or vacuum based deposition [19] techniques.Among various spacer layers, single layer graphene provides an attractive platform due to its atomic layer thickness, broadband photo responsivity and ease of integration over large areas. This was recently demonstrated by Paria et al., [5] who used a graphene monolayer as a separator between 70 nm Ag spheres. The field enhancement at the junction was calculated to be very large, and this was confirmed through Raman measurements of the graphene layer. In addition, the graphene photoresponsivity was found to be significantly enhanced, and found to be much larger than other plasmonically sensitized graphene photo detectors. [5,6,20,21] Li et al. have developed Cu NPs-graphene-Cu film system by directly depositing Cu nanoparticles on the CVD grown graphene which showed strong nearfield coupling between Cu NPs and Cu films. [22] Enhancement dependence on the laser incident angle was demonstrated and an optimum incident angle of 60° was identified for maximum enhance ment. Similarly, there have been other efforts to use graphene as separators between nanowires, [14] nanodimers, [12,23] photonic nanocrystals, and nanocavities for a multitude of applications. These graphenebased hybrids [13,18,22,24] show excellent Raman signal enhancement and hence have created a new pathway in the field of biosensing through surfaceenhanced Raman spectroscopy.In this paper, we report a new fabrication strategy involving selfassembly that exploits selective heterogenous nucleation to create graphene separated Au dimers. The most important observation is the existence of a window in the growth condi tions that yields preferential heterogeneous nucleation of a Noble metal dimers with sub-nanometer separation support strong electromagnetic field enhancement which has practical applications in surface enhanced Raman scattering (SERS), photodetection, and photocatalysis. Monolayer graphene is an excellent spacer material to practically realize uniform separation between the dimers. Here, directed microwave-assisted self-assembly of Au nanoparticle dimers is reported, separated by graphene monolayer over 1 cm 2 substrates. Detailed analytical models of Au particle formation kinetics explain the experimentally observed control of the density and sel...

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“…Thus, the oxygen plasma treated graphene facilitates adsorption of NH3 molecules on its surface, and when coupled with water vapor (from ambient as well as at the graphene/SiO2 interface due to wet processing) they subsequently interact with graphene and transfer charges. [22] Indeed for H2 plasma treated graphene, which led to a decrease in adsorbed oxygen (see above discussion) the carrier concentration was reduced leading to only slightly higher sensing performance (20% change in 10 min, 32% change in 30 min; refer to Fig. 3) compared to that of the pristine graphene (10% change in 10 min, 19% change in 30 min).…”

Section: Figmentioning

confidence: 91%