Using Patterned Self-Assembled Monolayers to Tune Graphene–Substrate Interactions

Negrito, Maelani; Elinski, Meagan B.; Hawthorne, Nathaniel; Pedley, Mckenzie P.; Han, Ming; Sheldon, Matthew; Espinosa‐Marzal, Rosa M.; Batteas, James D.

doi:10.1021/acs.langmuir.1c01136

Cited by 6 publications

(7 citation statements)

References 58 publications

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“…Depositing Graphene. The deposition of graphene on our substrates employed a method developed in-lab, 46 which was initially adapted from Song et al 47 Briefly, CVD-grown graphene on Cu was purchased (LG), and polystyrene (PS− MW 13 000, Sigma-Aldrich) at 31.5 mg/mL in toluene was spin-coated onto the surface at 300 rpm for 2 min as a selfreleasing layer. It was heated to 85 °C for 5 min to remove the solvent.…”

Section: Fabrication Ofmentioning

confidence: 99%

Studies of the Reactivity of Graphene Driven by Mechanical Distortions

et al. 2022

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In mechanochemistry, the application of controlled forces is key to altering reaction rates and pathways to direct product yields and selectivity. However, a fundamental knowledge gap exists between what is occurring on the atomic scale in mechanically driven reactions and the resulting macroscale outcomes. Two-dimensional (2D) materials, such as graphene, proffer a model system to study the impact of mechanical forces, such as strain, on chemical reactivity, as force distributions may be applied across a well-organized atomic-scale structure comprising a single layer of C atoms. Here, using Raman micro-spectroscopy and first-principles calculations, we have investigated the reaction of graphene, under varying degrees of strain, with 4-nitrobenzenediazonium tetrafluoroborate (4-NBD). We find that only with increased out-of-plane distortion (shifting the C atoms of graphene from sp 2 toward sp 3 electronic states) would the reactivity be increased, with larger out-of-plane distortions yielding greater reactivity. Density functional theory (DFT) calculations reveal that increasing the curvature of graphene decreases the activation barrier of 4-NBD functionalization and enhances the thermodynamic favorability of the reaction. Furthermore, we find that curvature affects the orientation of the graphene 2p z orbitals, and we then relate the thermodynamic feasibility of 4-NBD functionalization with the orbital orientation. These studies point to how the precise application of forces can be used to direct the functionalization of graphene for C−C bond forming reactions, which has significant implications for controlling its corresponding electronic structure in a well-defined fashion.

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Section: Fabrication Ofmentioning

confidence: 99%

Studies of the Reactivity of Graphene Driven by Mechanical Distortions

et al. 2022

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“…Our studies point to the ability to direct molecular migration experimentally as a means of tuning the physicochemical properties of 2D materials. We have previously shown that spatially controlled functionalization of graphene with azides can yield localized scattering of the graphene plasmon, and thus by depositing graphene on patterned substrates with controlled localized curvature, one can envision tracking migration to locations of high localized curvature using spatially resolved vibrational spectroscopies, , near-field scattering, or high-resolution optical fluorescence measurements …”

Section: Resultsmentioning

confidence: 99%

“…This can be realized by bonding a terminal N group across the CC bond network of graphene, forming an aziridine ring, − with individual molecule–graphene bonds breaking and reforming as the molecule moves. This class of functionalization has been reported to locally open a band gap in graphene, , and therefore it provides a way to tailor nanomaterials for optoelectronic purposes . Migration of a functionalized center on graphene provides a way to spatially control the local frontier energy levels as well as the carrier (electron/hole) concentrations and defect states.…”

Section: Introductionmentioning

confidence: 99%

“…This class of functionalization has been reported to locally open a band gap in graphene, 48,52 provides a way to tailor nanomaterials for optoelectronic purposes. 53 Migration of a functionalized center on graphene provides a way to spatially control the local frontier energy levels as well as the carrier (electron/hole) concentrations and defect states. Moreover, understanding how a ring moves on curved graphene can be crucial for driving cyclization reactions and facilitating the movement of such rings on curved graphene, which has been a key area of interest.…”

Section: ■ Introductionmentioning

confidence: 99%

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Two-Legged Molecular Walker and Curvature: Mechanochemical Ring Migration on Graphene

Banerjee,

Hawthorne,

Batteas

et al. 2023

J. Am. Chem. Soc.

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“…A discussion on surface passivation of graphene with PDs has been reported elsewhere . To reach at least about 90% surface coverage by a monolayer of PDs and to avoid the formation of dimers or trimers, surfaces of the sensors were rinsed with a compatible solvent. , Table shows the specific information on the PDs and corresponding solvents used in this work.…”

Section: Materials and Experimental Designmentioning

confidence: 99%

Defect Engineering of Graphene to Modulate pH Response of Graphene Devices

Angizi

Dalmieda

et al. 2021

Langmuir

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Graphene-based pH sensors are a robust, durable, sensitive, and scalable approach for the sensitive detection of pH in various environments. However, the mechanisms through which graphene responds to pH variations are not well-understood yet. This study provides a new look into the surface science of graphene-based pH sensors to address the existing gaps and inconsistencies among the literature concerning sensing response, the role of defects, and surface/solution interactions. Herein, we demonstrate the dependence of the sensing response on the defect density level of graphene, measured by Raman spectroscopy. At the crossover point (ID/IG = 0.35), two countervailing mechanisms balance each other out, separating two regions where either a surface defect induced (negative slope) or a double layer induced (positive slope) response dominates. For ratios above 0.35, the pH-dependent induction of charges at surface functional groups (both pH-sensitive and nonsensitive groups) dominates the device response. Below a ratio of 0.35, the response is dominated by the modulation of charge carriers in the graphene due to the electric double layer formed from the interaction between the graphene surface and the electrolyte solution. Selective functionalization of the surface was utilized to uncover the dominant acid–base interactions of carboxyl and amine groups at low pH while hydroxyl groups control the high pH range sensitivity. The overall pH-sensing characteristics of the graphene will be determined by the balance of these two mechanisms.

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Using Patterned Self-Assembled Monolayers to Tune Graphene–Substrate Interactions

Cited by 6 publications

References 58 publications

Studies of the Reactivity of Graphene Driven by Mechanical Distortions

Studies of the Reactivity of Graphene Driven by Mechanical Distortions

Two-Legged Molecular Walker and Curvature: Mechanochemical Ring Migration on Graphene

Defect Engineering of Graphene to Modulate pH Response of Graphene Devices

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