Raman nanodiamonds

Graphene has been prepared by different methods pyrolysis of camphor under reducing conditions (CG), exfoliation of graphitic oxide (EG), conversion of nanodiamond (DG) and arc evaporation of SiC (SG). The samples were examined by X-ray diffraction (XRD), transmission electron microscopy, atomic force microscopy, Raman spectroscopy and magnetic measurements. Raman spectroscopy shows EG and DG to exhibit smaller in-plane crystallite sizes, but in combination with XRD results EG comes out to be better. The CG, EG and DG samples prepared by us have BET surface areas of 46,... 

Eerrari AC, Robertson J (2004) Raman spectroscopy of amorphous, nanostructured, diamondlike carbon, and nanodiamond. Philos Trans R Soc Lond A 362 2477-2512... 

In situ Raman spectroscopy during heating in a controlled environment allows for a time-resolved investigation of the oxidation kinetics of carbon nanomaterials and can identify changes in material structure and composition during oxidation. In this chapter, we describe the application of in situ Raman spectroscopy to determine conditions for selective oxidation and purification of carbon nanotubes (CNT) and nanodiamond (ND). 

Raman analysis is performed using Raman microspectrometers in backscattering geometry. Analysis of nanodiamond requires the use of ultraviolet (UV) excitation and spectra were recorded using a Raman spectrometer with a 325-nm HeCd laser. Visible (VIS) Raman spectra were acquired using a 514-nm Ar-ion laser, a 633-nm HeNe laser, and a 785-nm semiconductor diode laser. 

Fig. 12.24 Raman spectra of carbon nanomaterials and corresponding optical images of (a) carbon black (514-rnn excitation) and (b) nanodiamond (325-nm laser excitation) before and after laser-induced light emission, recorded in Ar atmosphere. Carbon black is evaporated by the laser and redeposited as amorphous carbon around the excitation spot. ND is evaporated or transformed into graphitic carhon upon irradiation. The scale bar in the photograph is 15 pm...

Ferrari AC, Robertson J (2004) Raman spectroscopy of amorphous, nanostructured, dia-mond-like carbon, and nanodiamond. Phil Trans Roy Soc Lond A 362 2267-2565 Osswald S, Mochalin VN, Havel M, Yushin G et al (2009) Phonon confinement effects in the Raman spectrum of nanodiamond. Phys Rev B 80(7) 075419... 

Mochalin V, Osswald S, Gogotsi Y (2009) Contribution of functional groups to the Raman spectrum of nanodiamond. Chem Mater 21(2) 273-279... 

The Raman spectrum of the product of plasma spraying of nanodiamonds shows the formation of well-defined carbon onions (band at 1571 cm-1) and defective carbon onions (1592 cm-1).288 Raman spectroscopy was used to follow the effects of heavy-ion irradiation on nanocomposite carbon films.289 Laser-grown carbon microfibres were characterised by Raman microfibres,290 as were giant fullerene-like hollow spheres generated from C60 by compression at 57 GPa.291... 

Figure 5.16 Raman spectra of nanodiamond in dependence on the excitation wavelength (a) ( AlP 2005) and Raman spectmm of a macroscopic diamond (b) ( APS 1991).

A typical Raman spectrum of nanodiamond contains a number of signals that can be assigned to either sp - or sp -portions of the sample (Figure 5.16a). It apphes as a rule in doing so that all signals observed above 1360cm are related to the sp -portion as this value represents the band limit for sp -C-C-vibrations. 

Figure 33 shows spectra of natural, possibly interstellar, nanodiamond from the Or-gueil meteorite compared to a synthetic detonation diamond. They are very similar in displaying some p -like diamondlike character, which typically is manifested in Raman intensity at around 1330 cm as well as a sp -like disordered character around 1600 cm" the latter was attributed to the relatively large proportion of carbon atoms in disordered structural arrangements at the surface compared to those ordered inside these nanometer-sized minerals [51]. 

Figure 33 Raman spectra of interstellar nanodiamond from the Orgueil meteorite (above) and from a detonation diamond (below) both reveal a diamondlike sp character around 1330 cm and a disordered graphitelike sp character around 1600 cm attributed to surface effects. (After Ref. 51.)... 

HGM Hill, DC Smith, C Carabatos-Nedelec. The Raman spectra of interstellar and synthetic nanodiamonds. In GEORAMAN 99, Abstracts Volume, F Rull, ed. Valladolid, Spain University of Valladolid Press, 1999, pp 59-60. 

Figure 3.12 Raman spectra of carbon onions compared with those of nanodiamonds and graphite (X = 514.5 nm). The nanodiamond spectrum was plotted after suppression of the luminescence background approximated by a cubic polynomial...

Here, UV Raman spectroscopy is chosen in order to give a better Raman signal of diamond and to confirm its presence in the centre of the nanoparticles. As first shown by Sun et ai, the spectrum of nanodiamond excited by a visible radiation contains a luminescent background which should be removed [53]. Mykhaylyk et al. recently compared spectra obtained at 633, 488 and 244 nm (Figure 3.14) [16]. This comparison clearly demonstrated the advantage of using UV excitation, which also allows the intense diamond optic mode to generate in the spectrum. 

Spectra obtained at 244 nm are presented in Figure 3.15. This comparison clearly shows the presence of nanodiamond only in the carbon onions containing a diamond core. These results thus confirm observations made by TEM and EELS at the nano scale. It also proves the usefulness of UV Raman spectroscopy to characterize carbon compounds at the macroscopic scale. 

Figure 3.14 Multiwavelength spectra of nanodiamond. The Raman spectrum at 488 nm was plotted after subtraction of a luminescent background approximated by a cubic polynomial. This comparison clearly demonstrates the advantage of using UV radiation to analyse nanodiamond. Reproduced by permission of the American Institute of Physics from Mykhaylyk et al. [16], Figure 11, (2005) American Institute of Physics...

Figure 3.15 Raman spectrum of carbon onions compared with those of nanodiamonds (X = 244 ran)...

Mykhaylyk, O. O., Solonin, Y. M., Batchelder, D. N. and Brydson, R., Transformation of nanodiamond into carbon onions a comparative study by high-resolution transmission electron microscopy, electron energy-loss spectroscopy. X-ray diffraction, small-angle X-ray scattering, and ultraviolet Raman spectroscopy. Journal of... 

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