Effect of nitrogen doping on Raman spectra of multi‐walled carbon nanotubes

Bulusheva, L. G.; Okotrub, A. V.; Kinloch, Ian A.; Asanov, I. P.; Kurenya, A. N.; Kudashov, A. G.; Chen, X.; Song, Huaihe

doi:10.1002/pssb.200879592

Cited by 172 publications

(111 citation statements)

References 18 publications

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“…This effect could be caused by the nitrogen doping and variations in the degree of crystallinity. [ 35,36 ] In addition, the G-band exhibits a downshift that can be associated to the introduction of structural defects, which in this case includes nitrogen doping (Table 1 ). [ 37 ] Powder X-ray diffraction of all the samples showed refl ections around 2θ = 26 and 44 degrees, corresponding to the (002) and (100) planes of graphite ( Figure 4 a,b), respectively.…”

Section: Resultsmentioning

confidence: 99%

Controlling the Optical, Electrical and Chemical Properties of Carbon Inverse Opal by Nitrogen Doping

Morelos-Gómez

Mani-González

Aliev

et al. 2014

Adv Funct Materials

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Nitrogen-doped carbon inverse opal (CIO-N) is synthesized by a two-step process involving the infi ltration of carbon-nitrogen precursors within opals followed by the thermolysis and removal of the opal structure in hydrofl uoric acid (HF). Undoped samples exhibit a refl ection peak in the red region of the spectrum whereas N-doped samples display shifts to the blue region of the spectrum as the nitrogen content is increased. The degree of crystallinity of CIO-N strongly depends upon the nitrogen content and on the size of the precursor silica particles used to prepare the inverted opals. In addition, the introduction of nitrogen into the samples is able to increase the electrical conductivity by one order of magnitude from 2 to 30 S cm −1 (at room temperature). All samples are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), ultraviolet-visible (UV-Vis) spectroscopy, and electrical conductivity measurements. It is envisaged that CIO-N could have important applications in the fabrication of photonic crystals, photoconducting materials, molecular sensors, fi eld emission devices, capacitors, batteries, among many others.

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Section: Resultsmentioning

confidence: 99%

Controlling the Optical, Electrical and Chemical Properties of Carbon Inverse Opal by Nitrogen Doping

Morelos-Gómez

Mani-González

Aliev

et al. 2014

Adv Funct Materials

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“…and is also not sensitive to the nanotube alignment [32]. The intensity ratios D Q /D t and G Q /G t parallel/perpendicular to the flow direction were used to assess the degree of nanotube alignment.…”

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confidence: 99%

“…The D/G ratio is often used as a diagnostic tool for checking the degree of perfection of MWCNTs [32] or the degree of crystallinity in the nanotube structure [13]. A constant value of D/G,i nb o t h parallel and perpendicular geometries, then means that there is no change in the nanotube structure [40].…”

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confidence: 99%

Flow induced orientation of multiwalled carbon nanotubes in polycarbonate nanocomposites: Rheology, conductivity and mechanical properties

Abbasi

Carreau

Derdouri

2010

Polymer

218

202

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Flow induced orientation of multiwalled carbon nanotubes inWe investigated the effect of flow field and deformation rate on the nanotube alignment and on the properties of PC/multiwalled carbon nanotube nanocomposites. Samples of various MWCNT loadings were prepared by diluting a commercial masterbatch containing 15 wt% nanotubes using optimized melt mixing conditions. Different processing conditions were then used to systematically change the degree of nanotube alignment, from random orientation to highly aligned. Morphological studies and Raman spectroscopy analysis revealed that the nanotubes are preferentially aligned in the flow direction, particularly at large injection or compression rates. Rheological measurements corresponding to high shear rate conditions showed drastic changes in the viscoelastic behavior. The complex viscosity significantly decreased and percolation threshold notably rose. High degrees of nanotube alignment also resulted in a significant increase in the electrical percolation threshold. The mechanical properties of the nanocomposites for different nanotube loadings were also shown to depend on the processing conditions, and somehow improved when the material was processed at higher rates. Finally, we used a power-law type equation to correlate the percolation behavior and the nanotube alignment. The estimated percolation threshold and the power index, q, significantly increase with the degree of nanotube alignment as determined by Raman analysis.

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“…It is possible that the increase in the nanoparticle density on the nanotube surface is due to an increase in imperfec tion on their surface, because the nitrogen containing CNT with more defect structures were used in this experi ment. 16 The procedure developed for CdS precipitation makes it possible to synthesize nanoparticles on the silicon plate surface and on the CNT surface. The size of the CdS nanoparticles is controlled by the duration and tempera ture of precipitation.…”

Section: Rusults and Discussionmentioning

confidence: 99%

Synthesis of a hybrid material from CdS nanoparticles and carbon nanotubes

et al. 2010

Self Cite

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A method for synthesis of a hybrid material from CdS nanoparticles and carbon nanotubes (CNT) by the precipitation of CdS nanoparticles on the CNT surface from an aqueous solution containing the Cd II salt, thiourea, and ammonia was developed. The dependences of the size of particles formed on the CNT on the temperature of the solution and the duration of precipita tion were observed. The degree of imperfection of the CNT surface exerts a substantial effect on the density of the precipitated CdS particles.The development and use of nanoparticles of semicon ductors is of interest for the preparation of photoabsorbing and photoemitting cells. The range of absorption and lu minescence frequencies depends on the nanoparticle size. Hybrid nanosystems combining the properties of one di mensional carbon nanotubes (CNT) and quantum dots of semiconducting materials are being actively developed presently. It is expected that the interaction of semicon ducting nanoparticles with light would result in the elec tron photocurrent through the nanotube and localization of the hole on the nanoparticle. This would allow one to desigh new types of photogalvanic devices. 1 Recently it was repeatedly reported the precipitation of various types of nanoparticles of metal sulfides and selenides, such as CdSe (see Ref.2), Cu 2 S (see Ref.3), and CdS (see Refs 4-6) on the CNT. In particular, modified CdS nano particles were pre prepared and then precipitated from solution on the CNT surface, which made it possible to use such systems as biosensors. 7 During the electrochemical precipitation of CdS nanoparticles ∼15 nm in diameter on bamboo like nanotubes 100 nm in diameter, the CNT were pre oxidized with nitric acid for better precipitation. 8 The photoconductivity of the hybrid CdS/CNT materials was enhanced. The precipitation of CdSe nanoparticles on bundles of double wall CNT was described. 9 The CNT were pre fluorinated to provide a more uniform distribu tion of nanoparticles on the surface. A more complicated multistep approach to the formation of CdS nanoparticles on the nanotube surface is known. 6 By oxidizing the CNT surface with a mixture of acids the surface was firstly func tionalized with carboxyl groups and then Cd 2+ ions were "cross linked" to these groups. As a result of the interac tion with Na 2 S, CdS nanoparticles ∼8 nm in size were formed on the CNT surface.Hydrogen sulfide is often used for the synthesis of CdS. Hydrogen sulfide should be replaced by less toxic organic sulfur containing compounds capable of acting as a sup plier of sulfur atoms. One of the most available sulfur containing reagents of this type is thiourea (NH 2 ) 2 CS (Thio). For example, CdS films were obtained 10,11 from aqueous solutions containing Thio, Cd II salts, ammonia, and NaOH. A possibility to prepare CdS nanoparticles by this reaction was described. 12 The purpose of the present work is to study the forma tion of CdS nanoparticles on the surface of an array of multiwalled CNT aligned perpendicularly to the silicon support using the thio...

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Effect of nitrogen doping on Raman spectra of multi‐walled carbon nanotubes

Cited by 172 publications

References 18 publications

Controlling the Optical, Electrical and Chemical Properties of Carbon Inverse Opal by Nitrogen Doping

Controlling the Optical, Electrical and Chemical Properties of Carbon Inverse Opal by Nitrogen Doping

Flow induced orientation of multiwalled carbon nanotubes in polycarbonate nanocomposites: Rheology, conductivity and mechanical properties

Synthesis of a hybrid material from CdS nanoparticles and carbon nanotubes

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