Spatially Resolved Bottom‐Side Fluorination of Graphene by Two‐Dimensional Substrate Patterning

Abstract

Patterned functionalization can, on the one hand, open the band gap of graphene and, on the other hand, program demanding designs on graphene. The functionalization technique is essential for graphene‐based nanoarchitectures. A new and highly efficient method was applied to obtain patterned functionalization on graphene by mild fluorination with spatially arranged AgF arrays on the structured substrate. Scanning Raman spectroscopy (SRS) and scanning electron microscopy coupled with energy‐dispersive X‐ray spectroscopy (SEM‐EDS) were used to characterize the functionalized materials. For the first time, chemical patterning on the bottom side of graphene was realized. The chemical nature of the patterned functionalization was determined to be the ditopic scenario with fluorine atoms occupying the bottom side and moieties, such as oxygen‐containing groups or hydrogen atoms, binding on the top side, which provides information about the mechanism of the fluorination process. Our strategy can be conceptually extended to pattern other functionalities by using other reactants. Bottom‐side patterned functionalization enables utilization of the top side of a material, thereby opening up the possibilities for applications in graphene‐based devices.

Recent Advances in Fluorinated Graphene from Synthesis to Applications: Critical Review on Functional Chemistry and Structure Engineering

“…However, the lacking of the structure engineering would limit the exploitative peculiarity and application of FG. [54,65,71,[93][94][95]141,149,184,220] Therefore, the elaborate structure engineering for customizing the structure and performances of FG is the most important research point in the past several years, which is also the urgent and significant avenue in its future development. The fluorine content is the simplest and fundamental character of FG, which has been introduced in the above intrinsic properties section.…”

“…[95] Thus, the targeted fluorination on the specified region on graphene sheet was realized, which effectively regulated the characters of the specified regions, such as surface energy, friction characteristic, electrical conductivity. [93][94][95][96] As another approach, one fluoropolymer was selected as a shielding layer to cover the surface of graphene. Subsequently, the laser was utilized and controlled to accomplish the selective radiation of the fluoropolymer.…”

“…Afterward, graphene was transferred onto the surface of the substrate, and its bottom surface was selectively fluorinated by the decomposed AgF under a raised temperature. [93] The abovementioned selective fluorinations of graphene sheets were mainly realized by defining the contact regions between graphene and the fluorine sources. In contrast, Deng et al operated the selective fluorination through regulating the reactivity of the specific graphene regions.…”

“…application. [92,93] Notably, the structure engineering is always closely dependent on the progress of fluorination chemistry and corresponding fluorination methods of FG. [33,84,239,240] Liu et al proved that the defect on graphene sheet possessed a higher fluorination reactivity through experiments and DFT calculations.…”

“…B) Illustrative image of the structured fluorination on graphene by 2D substrate patterning. Reproduced with permission [93]. Copyright 2020, The Authors, published by Wiley-VCH.…”