Chemical Stability of Graphene Fluoride Produced by Exposure to XeF₂

Abstract

Fluorination can alter the electronic properties of graphene and activate sites for subsequent chemistry. Here, we show that graphene fluorination depends on several variables, including XeF2 exposure and the choice of substrate. After fluorination, fluorine content declines by 50-80% over several days before stabilizing. While highly fluorinated samples remain insulating, mildly fluorinated samples regain some conductivity over this period. Finally, this loss does not reduce reactivity with alkylamines, suggesting that only nonvolatile fluorine participates in these reactions.

Solvent‐Based Soft‐Patterning of Graphene Lateral Heterostructures for Broadband High‐Speed Metal–Semiconductor–Metal Photodetectors

“…We find that after fluorination of CVD graphene on Ni/ Cu substrates, its subsequent transfer by traditional poly(methyl methacrylate) (PMMA) method [21] and patterning alter its insulating properties. XPS measurement on the transferred FG ( Figure 1c) shows a strong decrease in the intensity of F1s peak, indicating a loss of F content [18] (from 24.5% in as-prepared FG on Cu foil to 4.4%). We attribute this to the loss of the insulating properties of transferred FG.…”

“…[12] The binding of F radicals to graphene leads to surface activation and band gap opening, [11][12][13] rendering the resultant FG useful for applications ranging from as a seed layer for dielectric deposition [14,15] to as a growth precursor for synthesis of new 2D materials [16] and a building block for 2D heterostructures. [17] While FG, like some of the other functionalized graphene forms, holds great promises as a complementary material for next generation graphene-based electronics, it can readily defluorinate under humid conditions or when in contact with acetone [7,18] Such a phenomenon, considering acetone an important solvent for FG transfer and patterning process, can seriously undermine the potential of FG for widespread applications. This is because even a marginal change in the degree of fluorine coverage on graphene can turn FG from an insulator to a semiconductor or even a conductor, drastically changing the function and performance of electronic devices.…”

Two‐Dimensional Fluorinated Graphene: Synthesis, Structures, Properties and Applications

“…[[qv: 4a]],[[qv: 12a]],[[qv: 22c]] The removal of both C and F atoms in fluorographene was observed by a prolonged annealing time at high temperature (≈450 °C). [[qv: 4a]] In addition, according to XPS data, fluorinated graphene, prepared using XeF 2 gas on SiO 2 , Au, and Cu substrates, lost approximately 50–80% of the initial F/C ratios over 10 days until the F/C ratios were not changed 61. The change in C‐F bonds by annealing at different temperatures was also demonstrated by an increase in electrical conductivity (Figure 10b).…”

Homoepitaxial graphene tunnel barriers for spin transport

“…20 However, fluorine adatoms on graphene are not very stable and any fluorinated areas must be capped to prevent decomposition. 21 Hydrogenation of graphene, accomplished using a wet chemical Birch reduction process, discussed elsewhere in detail, 22 is much more stable. Although hydrogenation can also be accomplished using low energy hydrogen plasmas, 23,24 the Birch reduction process does not introduce defects.…”