I want to know why peaks are shifted in GO, in general if I deconvolute it I used to get peaks at 283.3, 284, 285.7, 287.7. Why I am getting peaks in such wird position? any suggestion for me? I went through different articles found that 284 belong to sp2, 285,7 to sp3, 288 carboxy group. Help in figuring out why I am getting peak at 283.3 and what it may be?
Looks like you need to calibrate the binding energy scale; likely the lowest BE peak should be 284.8 for hydrocarbons. If you used charge neutralisation then this usually shifts peaks a little to lower BE.
You'll get a variety of peaks for C 1s, so looking at graphene is very difficult. The graphene species may be fittable with an assymetric peak, as used for metallic photoelectron peaks, due to the high conductivity of graphene. However, unless your sample was grown in vacuum and never exposed to atmosphere, you will have contamination with hydrocarbons and carbon oxides (single and double bonded usually at ~286 and ~288 eV). There are a tonne of literature on XPS of carbon, and the NIST XPS database will show you a lot of the older ones. The problem is that the graphene signal will likely be sat very close to the hydrocarbon contamination, making peak fitting very difficult. Likewise delineating the different species of the O 1s signal will be difficult.
Suggest you measure a piece of metal along with the GO sample, since you'll find the same contaminants of C-C, C-H, C-O, C=O. Then you can apply your fitting parameters to the GO samples, and hopefully the fit will be insufficient, requiring an extra peak at the right BE for graphene!
#Ben F. Spencer:-- Respected sir, I understand the effect of charge neutralisation but do you think that it led to peak shift of 1ev or more if sample is insulating like in my case (Graphene Oxide).
Secondly, I didn't get your idea of taking XPS on a metal sheet, For metals there will be no charge neutralisation effect which again will lead hydrocarbons peak to be at some different position than the insulator sample.
#Ben F. Spencer:-- Sir, I would like to ask one more question i.e every research group quote 284 or 284.5 as signature of carbon (Sp2). Kindly comment on this in reference to charge neutralization effect as carbon is of conducting nature.
- Badges
- Science topic
- Similar topics
- Physical Sciences
- Materials Science
- Material Characterization