On the role of functional groups in the formation of diazonium based covalent attachments: dendritic vs. layer-by-layer growth

Multilayered growth is often observed upon electrografting aryl diazonium derivatives on graphitic substrates due to the reactive nature of aryl radicals. The mechanism of the multilayer formation has been investigated either by measuring the thickness of the grafted layer, the charge transfer, or via simulations. Spectroscopy and in particular microscopy approaches are underrepresented. Herein, we demonstrate a comparative characterization of the multilayer growth of two diazonium derivatives on highly oriented pyrolytic graphite using a combination of cyclic voltammetry, atomic force microscopy, and scanning tunneling microscopy. While dendritic growth is observed for 4-nitro phenyl diazonium (4-NBD), 4-carboxy phenyl diazonium (4-CBD) shows layer-by-layer growth upon increasing the molecular concentration, revealing the impact of the functional groups on the growth mechanism.

Automated summary

Multilayered growth is commonly seen when aryl diazonium derivatives are electrografted onto graphitic substrates. The mechanism of this growth has been studied through various methods, including measuring layer thickness, charge transfer, and simulations. However, spectroscopy and microscopy approaches have been underrepresented. This study presents a comparative characterization of multilayer growth using cyclic voltammetry, atomic force microscopy, and scanning tunneling microscopy, showing the influence of functional groups on the growth mechanism.