While analysing the XPS spectrum of one newly synthesized carbon material, I have observed a peak at 288 eV which is deconvoluted into three peaks at 284.6 eV, 286 eV and 288 eV. I was expecting 2 major peaks for binding energy corresponds to C-C (sp) and C-C (sp2). Can anyone explain this discrepancy in the spectrum?
The above-mentioned spectrum is attached to this.
Dear Dr. Arya J S,
could it be possible that the analyzed sample was contaminated with carbonate-like compounds present in the atmosphere? If yes, you can try to reduce/remove by argon sputtering. In this case, use lowest energy argon beam available (e.g. 200eV or 500eV) or argon clusters to prevent/minimize chemical damage to the underlying material.
For more details please see the following note/paper:
-Thermo-Scientific XPS: https://xpssimplified.com/elements/carbon.php
-Binding Energy Referencing for XPS in Alkali MetalBased Battery Materials Research (II): Application to Complex Composite Electrodes
Steffen Oswald, Franziska Thoss, Martin Zier, Martin Hoffmann, Tony Jaumann, Markus Herklotz, Kristian Nikolowski, Frieder Scheiba, Michael Kohl, Lars Giebeler, Daria Mikhailova and Helmut Ehrenberg
Batteries, 4, 36 (2018); doi:10.3390/batteries4030036
Best regards, Pierluigi Traverso
Can you provide some more info about the intensity ratios of your components? It sounds like your major component is 288eV, but how about the others?
If one is really low, that might be a contaminant and you can follow Pierluigi Traverso 's strategy, if both have the same height, it's more likely it's something about your process.
If it isn't some kind of data you need to keep secret due to evil competitors, you could also show us the spectrum.
Dear Jürgen Weippert ,
The compound contains sp C-C and sp2 C-C. So, I was expecting the corresponding XPS peaks at 285.2 and 284.3 eV respectively. However, the spectrum obtained does not contain these peaks. Instead, a major peak at 288 eV is present. I want to know generally a peak at 288 eV corresponds to which type of carbon bonding.
The obtained spectra are attached above.
OK, assuming your sample is not charging [and since you have a decent narrow signal I'd say it is that way], a 288eV peak could represent various kind of electron-rich carbonyls, both M-CO and -CHO bonding situations. Since you also have a significant O1s signal you could check if the position of that peak matches the position of carbonyls.
You can get reference spectra from the NIST database:
https://srdata.nist.gov/xps/EngElmSrchQuery.aspx?EType=PE&CSOpt=Retri_ex_dat&Elm=C
Based on the survey spectrum your sample contains, I would say, about 10 at. % of oxygen. This means that the C1s spectrum presented is an artifact. I can suggest two reasons:
1. Charging issues, as it was already mentioned.
2. Something went wrong during data export, which reversed and shifted the binding energy axis.
- Badges
- Science topic
- Similar topics
- Physical Sciences
- Materials Science
- Materials
- Carbon Materials