The raman spectrum of a sample (biomass derived carbon material) shows only two brooad peaks at about 1353 cm-1 and 1584 cm−1, assigned to D-band and G-band, respectively. The ID/IG ratio was found to be 1.05. What does this value indicate? According to literature, While G-band is characteristic of graphite, D-band is attributed to defects, curved graphite sheets and lattice distortions in the carbon structures (Li et al. 2007). Hence, the ratio of intensity of D-band to intensity of G-band (ID/IG) is an indication of defects or graphitic order. Does it mean that there is a fixed scale of ratio by which one can ascertain the nature of material (amorphous or crystalline)? If so, can I say my material is amorphous carbon since the ID/IG ratio is more than one? I have attached the specrtum for kind perusal.
The D-band in graphitic materials was originally mistakenly attributed to the edge plane, however a D-band was recorded for HOPG that had been doped with boron atoms [Chem. Rev., 2008, 108, 2646-2687]. The D-band indicates disorder in the graphitic structure, but does not necessarily indicate sp3 hybridization. A D/G of 1.05 surely indicates a high defect/disorder density but I will advice you to study your carbon material with XPS to understand further.
As for amorphous carbon, trace your G-band position and D/G on the Ferrari Amorphization Trajectory. See Figure 4 in reference below.
http://carbon.utsi.edu/downloads/raman_dlc_diamond.pdf
In origin, the D line is sp3 hybridised carbon and the G line is sp2 hybridised carbon, so I am not sure you can make any conclusions about graphitic content. At a glance, it looks like amorphous carbon.
In origin, the D line is sp3 hybridised carbon and the G line is sp2 hybridised carbon, so I am not sure you can make any conclusions about graphitic content. At a glance, it looks like amorphous carbon.
The D-band in graphitic materials was originally mistakenly attributed to the edge plane, however a D-band was recorded for HOPG that had been doped with boron atoms [Chem. Rev., 2008, 108, 2646-2687]. The D-band indicates disorder in the graphitic structure, but does not necessarily indicate sp3 hybridization. A D/G of 1.05 surely indicates a high defect/disorder density but I will advice you to study your carbon material with XPS to understand further.
As for amorphous carbon, trace your G-band position and D/G on the Ferrari Amorphization Trajectory. See Figure 4 in reference below.
http://carbon.utsi.edu/downloads/raman_dlc_diamond.pdf
Thank you Dr.Hugh J Byrne and Dr. Isaiah Owusu Gyan for interesting, helpful answers.
To qualify Isaiah's point..... disorder in an ideal graphene network is usually a disruption of the sp2 character of the carbon network, which introduces sp3 character!
I consider that the determination of amorphous or crystalline structure should not be dependent on the Raman spectrum, but should on XRD, HRTEM and SAED characterizations. Actually, the Raman spectra of oxygenated graphite and reduced graphene oxide are close to the one you provided. For detailed structural analyses, more characterizations are needed.
Thank you Dr.Huawen Hu for answer. If that is the point, what useful information can be obtained from Raman spectrum, as all carbon materials show the G and D bands? How can I ascertain that a particular type of carbon matrial was sucessfully synthesized using biomass (it's non-edible oil cake in this case) from hydrothermal carbonization followed by calcination in an inert atmosphere at 650 oC?
Dear Lakshminarayana,
I consider that if the carbon materials you fabricated has good exemplified applications such as environmental remediation, polymer composites, and catalysis, you achieve something more important. The structure of the material may be considered later.
Only using Raman, we cannot reach a definite information on the structure, as I have said before that many different kinds of carbons can be indexed to the similar Raman spectra.
Considering your synthetic process, many control samples also need a parallel test, such as the one obtained before the high-temperature treatment. As a result, you can get the information the effect of the high-temperature calcination. The calcination temperature can also be tried to change, so you can find a temperature-dependent behavior of the materials with respect to structure and properties.
We may ensure that your carbon materials have abundant defects due to the high intensity ratio of D band to G band.
The spectrum indeed indicates that the sample is amorphous in nature which can be further ascertained by XRD.
The following paper may help in interpreting what you have and understanding the underlying phenomena ...
https://www.researchgate.net/publication/224487145_Raman_spectroscopy_on_amorphous_carbon_films
Article Raman Spectroscopy on Amorphous Carbon Films
Thank you Dr. Nita Dilawar and Dr. S Ravi P Silva for interest shown. I will go through paper.
Some degree of amorphization is present in the structure, but the ratio D/G shows structure having a good percentage of crystalline. Also, no D' peak in the spectrum, you need to do XRD and TEM/SAEDP to confirm it.
The following paper may interrest you : https://www.researchgate.net/publication/233800422_Determination_of_crystallite_size_in_polished_graphitized_carbon_by_Raman_spectroscopy
Article Determination of crystallite size in polished graphitized ca...
You could check Prof. A C Ferrari's papers,
doi:10.1038/nnano.2013.46
http://dx.doi.org/10.1103/PhysRevLett.97.187401
Tahnk you all for providing useful references. I will refer them. Meanwhile looking forward to further value addition from RG colleagues.
what are the main settings required to scan carbon quantum dots by Raman? and what is the best form of the sample? carbon dots are water-soluble.... thanks
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