Actually, I want to know why the graphene can absorb the light during 220-1000 nm wavelength, but oxide graphene can not.
Thanks very much for your time.
Dear Mr. Lkiu,
this is a electromagnetic field problem of the matching of the field impedance to the material impedance in this frequency range. At my opinion is the oxide graphene not matched with his impedance to the field impedance of the near impedance field of the infrared field.
If we have a mismatch, then we have a great reflection and not absorption.
Sincerely Yours
F. Gräbner
The band gap of graphene oxide is larger than the band gap of graphene. In adsorption mechanism, photons with energy equal to the band gap energy can adsorbed. These photons have enough energy to exited electrons to the higher level. The band gap of graphene is in the range of infrared light but the band gap of graphene oxide is in the range of photons with higher energy.
The size of conjugated structure is much smaller in graphene oxide (GO) than in reduced graphene oxide (rGO). Consequently, GO adsorbs light at much smaller wavelengths. In our recent work, we found that the color of freeze-dried GO is lighter when it is oxidatively functionalized at a higher degree.
Please see our recent paper published in Chem. Sci.
http://pubs.rsc.org/en/content/articlelanding/2015/sc/c5sc03828f
Feel free to contact me if you have any further questions.
Best,
Ji
http://pubs.rsc.org/en/content/articlelanding/2015/sc/c5sc03828f
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