Covalent modification of graphene and graphite using diazonium chemistry : Tunable grafting and nanomanipulation

Greenwood, J. and Phan, T.H. and Fujita, Y. and Li, Z. and Ivasenko, O. and Vanderlinden, W. and Van Gorp, H. and Frederickx, W. and Lu, G. and Tahara, K. and Tobe, Y. and Uji-I, H. and Mertens, S.F.L. and De Feyter, S. (2015) Covalent modification of graphene and graphite using diazonium chemistry : Tunable grafting and nanomanipulation. ACS Nano, 9 (5). pp. 5520-5535. ISSN 1936-0851

Abstract

We shine light on the covalent modification of graphite and graphene substrates using diazonium chemistry under ambient conditions. We report on the nature of the chemical modification of these graphitic substrates, the relation between molecular structure and film morphology, and the impact of the covalent modification on the properties of the substrates, as revealed by local microscopy and spectroscopy techniques and electrochemistry. By careful selection of the reagents and optimizing reaction conditions, a high density of covalently grafted molecules is obtained, a result that is demonstrated in an unprecedented way by scanning tunneling microscopy (STM) under ambient conditions. With nanomanipulation, i.e., nanoshaving using STM, surface structuring and functionalization at the nanoscale is achieved. This manipulation leads to the removal of the covalently anchored molecules, regenerating pristine sp2 hybridized graphene or graphite patches, as proven by space-resolved Raman microscopy and molecular self-assembly studies. © 2015 American Chemical Society.