Spectroscopy of Covalently Functionalized Graphene

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• 作者：Sandip Niyogi ; Elena Bekyarova ; Mikhail E. Itkis ; Hang Zhang ; Kristin Shepperd ; Jeremy Hicks ; Michael Sprinkle ; Claire Berger ; Chun Ning Lau ; Walt A. deHeer ; Edward H. Conrad ; Robert C. Haddon
• 刊名：Nano Letters
• 出版年：2010
• 出版时间：October 13, 2010
• 年：2010
• 卷：10
• 期：10
• 页码：4061-4066
• 全文大小：458K
• 年卷期：v.10,no.10(October 13, 2010)
• ISSN：1530-6992

文摘

In order to engineer a band gap into graphene, covalent bond-forming reactions can be used to change the hybridization of the graphitic atoms from sp² to sp³, thereby modifying the conjugation length of the delocalized carbon lattice; similar side-wall chemistry has been shown to introduce a band gap into metallic single-walled carbon nanotubes. Here we demonstrate that the application of such covalent bond-forming chemistry modifies the periodicity of the graphene network thereby introducing a band gap (0.4 eV), which is observable in the angle-resolved photoelectron spectroscopy of aryl-functionalized graphene. We further show that the chemically-induced changes can be detected by Raman spectroscopy; the in-plane vibrations of the conjugated π-bonds exhibit characteristic Raman spectra and we find that the changes in D, G, and 2D-bands as a result of chemical functionalization of the graphene basal plane are quite distinct from that due to localized, physical defects in sp²-conjugated carbon.

<h4>Keywords:h4> Graphene; covalent chemistry; band gap; ARPES; Raman