Covalent Functionalization of Graphene by Nucleophilic Addition Reaction: Synthesis and Optical‐Limiting Properties

Abstract

Covalent functionalization of reduced graphene oxide (rGO) was performed by using conjugated polymers with different monomers through nucleophilic addition of nitrogen anions to rGO. Three conjugated polymers containing tetraphenylethylene, carbazole, and phenyl groups were used, and as a result of π-π interactions and the "polymer-wrapping" effect, the dispersion stability of rGO was improved. Even if the reaction site in the polymers was the same, there were great differences in the reactivities of the polymers, the dispersion stabilities of the resultant composites, and also the optical limiting (OL) performances of the resultant composites. The differences may be attributed to the π-conjugated structure and steric hindrance of the moiety in the polymer skeleton, which has scarcely been reported. Besides, the resultant rGO-P1 and rGO-P3 materials both showed excellent OL responses, even at 4 μJ. This behavior should enable their potential application in photonic and optoelectronic devices to protect human eyes or optical sensors from damage by intense laser irradiation.

Covalent functionalization of 1D and 2D sp2-carbon nanoallotropes – twelve years of progress (2011–2023)

“…Three conjugated polymers, each with different monomers, including tetraphenylethylene (TPE), carbazole, and phenyl groups, were used for the functionalization of rGO. 143 Sodium hydride was employed for the deprotonation of NH moieties in the monomer. Despite having the same reactive sites, each polymer displayed a difference in reactivities attributed to the different monomers used.…”

An Overview of Functionalized Graphene Nanomaterials for Advanced Applications

“…For instance, Xu et al [ 59 ] covalently functionalized RGO with three conjugated polymers containing carbazole, tetraphenylethylene, and phenyl moieties. They found an improved dispersion stability of RGO and, somehow unexpectedly, OL behavior strongly dependent on the type of polymer grafted onto nanoplatforms.…”

From single-layer graphene to HOPG: Universal functionalization strategy with perfluoropolyether for the graphene family materials

“…The product is usually highly stable and the linkage of a vast number of chemicals is allowed, from single atoms to polymers [18][19][20][21]. Some routes for the covalent functionalization of graphene are hydrogenation [22,23], fluorination [24,25], substitution of already present oxygenated groups, nucleophilic addition and electrophilic substitution [26,27], radical reactions [28] or controlled oxidation to give graphene oxide (GO) [29]. Fluorination and perfluoroalkylation of carbon-based polyaromatic materials have already been widely studied in order to enhance their chemical-physical stability [30][31][32].…”