Thiophenol‐Modified Fluorographene Derivatives for Nonlinear Optical Applications

Abstract

The synthesis and characterization of two thiophenol‐modified fluorographene derivatives, namely methoxythiophenol‐and dimethylaminothiophenol‐modified fluorographenes, are reported, while their third‐order nonlinear optical response were thoroughly investigated under both visible (532 nm) and infrared (1064 nm) with 35 ps and 4 ns laser pulses. The graphene derivatives were obtained by partial nucleophilic substitution/reduction of fluorographene by the corresponding organic thiophenols, and were fully characterized by techniques including infrared/Raman spectroscopy, X‐ray photoelectron spectroscopy, atomic force spectroscopy, and high‐resolution transmission microscopy. This type of modification resulted in graphenic structures where the attached thiol groups, sp2 domains, and the residual fluorine groups act as donors, π bridges, and acceptors, respectively. Both derivatives exhibited large nonlinear optical response compared to fluorographene, and have potential applications in optical limiting as an alternative to fullerenes.

Diethylamino‐fluorographene: A 2D material with broadband and efficient optical limiting performance (from 500 to 1800 nm) with very large nonlinear optical response

“…To ease the comparisons of the effect of fluorographene functionalization on the change of the sign and the enhancement of fluorographene's NLO response, the corresponding NLO parameters of two thiophenol-modified fluorographenes, recently studied, are also included in this table. [24] As shown in Table 1, all fluorographene derivatives presented here exhibit much larger NLO response than pristine fluorographene for both excitation wavelengths. By contrast the diethylamino derivative was found to exhibit the largest NLO response, exceptionally larger than that of pristine fluorographene and significantly larger than that of the two thiophenol derivatives.…”

“…As can be seen CDEA's absorption spectrum is structureless, exhibiting the typical characteristics of graphenic materials, and is similar to the corresponding absorption spectra of pristine fluorographene and the other thiophenol-modified fluorographene derivatives. [24] In Figure 2 some representative "open-aperture" (OA) and "divided" Z-scans of a 0.02 mg ml −1 CDEA dispersion in acetone, obtained using visible and infrared excitation, are presented. The continuous lines represent the best fit of the experimental data (solid points) as discussed elsewhere.…”

“…In that respect, the selection of the diethyl-amino-group has been decided, which is known to possess a much stronger electron-donor property than the organic thiol groups previously employed. [24,25] So, the diethyl-aminofluorographene (CDEA) was prepared [25] and its NLO properties and optical limiting action are studied here under both visible (532 nm) and infrared (1064 nm), 4 ns laser excitation.…”

Electronic structure and second-order nonlinear optical properties of lemniscular [16]cycloparaphenylene compounds

“…The design and synthesis of materials with large nonlinear optical (NLO) performance have attracted considerable attention due to their potential applications in optical and optoelectronic devices. [1][2][3][4][5][6][7][8] However, second-order NLO properties can be characterized at the molecular level with second-order polarizability, which is the most important point in practical applications. The necessary requirement for second-order NLO materials is a non-centrosymmetric electronic structure.…”

Tunable one-step double functionalization of graphene based on fluorographene chemistry

“…However, the low reactivity of graphene and achieved low degree of functionalization remain obstacles against direct graphene functionalization. In the last decade, fluorographene 8,9 (FG) has been launched as an alternative precursor for the preparation of covalently functionalized graphene derivatives bearing hydrocarbyl (alkyl, alkenyl, alkynyl and aryl), [10][11][12][13] amino, [14][15][16] cyano and carboxylic, 17 hydroxyl, 18,19 and sulfhydryl [20][21][22][23] moieties. From a chemical point of view, FG behaves as an electrophile that reacts readily with nucleophiles, 14,24 usually under mild conditions.…”