Method for graphene functionalization that preserves characteristic electronic properties such as the quantum hall effect and enables nanoparticles deposition
Inventors
Lock, Evgeniya H. • Osofsky, Michael S. • Auyeung, Raymond C Y • Myers-Ward, Rachael L. • Gaskill, David Kurt • Prestigiacomo, Joseph
Assignees
Publication Number
US-11572281-B2
Publication Date
2023-02-07
Expiration Date
2038-01-29
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Abstract
A method for graphene functionalization that preserves electronic properties and enables nanoparticles deposition comprising providing graphene, functionalizing the graphene via non-covalent or covalent functionalization, rinsing the graphene, drying the graphene, and forming functionalized graphene wherein the functionalized graphene preserves electronic properties and enables nanoparticles deposition. A functionalized graphene wherein the graphene functionalization preserves electronic properties and enables nanoparticles deposition.
Core Innovation
This disclosure teaches a method to functionalize graphene to allow for modulation of graphene's electrical properties as well as for deposition of nanoparticles, such as oxides, metals, and quantum dots. The functionalization methods include both covalent and non-covalent approaches, with specific molecules used for each type to maintain graphene's structural and electronic integrity.
The problem addressed is the inert chemical nature of graphene, which necessitates chemical functionalization for integrating graphene with other materials, attaching biomolecules and catalysts, and allowing deposition of metals and dielectrics. Existing covalent functionalization methods often damage graphene's electrical properties, while non-covalent methods have been limited in their exploration on monolayer graphene. Preservation of graphene's characteristic electronic properties, such as the quantum Hall effect, while enabling functionalization and nanoparticle deposition, remains challenging.
The invention provides a unique covalent azide-based functionalization that does not introduce defects (no D peak in Raman spectroscopy), preserving the quantum Hall effect typical only for pristine graphene. Non-covalent functionalization with pyrene- and pyridine-based molecules is enabled through π-π stacking interactions. Both methods are tunable by adjusting molarity, incubation time, and in the covalent case, UV exposure. This preserves electronic properties while enabling nanoparticle attachment.
Claims Coverage
The patent claims 12 inventive features across 11 claims focusing on methods for graphene functionalization and nanoparticles deposition via covalent and non-covalent means, preserving graphene's electronic properties.
Non-covalent functionalization using specified molecules
Functionalizing graphene via non-covalent functionalization comprising providing one from the group consisting of 1-hydroxypyrene solution, 1 pyrenecarboxylic acid dissolved in methanol, and 4-aminomethyl pyridine, followed by incubation.
Incubation parameters for non-covalent functionalization
Incubating graphene for 1 hour when using 1-hydroxypyrene solution or 1 pyrenecarboxylic acid, and for 6 hours at 190° C. when using 4-aminomethyl pyridine.
Rinsing and drying steps for non-covalent functionalization
Rinsing the graphene using methanol and isopropyl alcohol and drying with nitrogen.
Nanoparticle deposition on functionalized graphene
Depositing nanoparticles comprising oxide nanoparticles on the functionalized graphene using a nanoparticle suspension, mixing with methanol, incubating with pyrene or TFPA solution, applying UV to activate attachment, then rinsing and drying.
UV activation parameters for nanoparticle attachment
Applying UV light to the nanoparticle and functionalized graphene for about 10-30 minutes.
Sequential graphene layer attachment
Attaching a sequential graphene layer onto the functionalized graphene in both covalent and non-covalent functionalization methods.
Attachment of two-dimensional materials
Attaching two-dimensional materials selected from MoS2, phosphorene, or boron nitride onto functionalized graphene.
Covalent functionalization using azide-containing molecules
Functionalizing graphene via covalent functionalization using molecules such as N-ethylamino-4-azidotetrafluorobenzoate (TFPA-NH2), TFPA-OH, TFPA-COOH, TFPA-SH, TFPA-NHS, or phosphorine-ethylamino-4-azidotetrafluorobenzoate (TFPA-PO3) in solvents including methanol, toluene, or dichloromethane, followed by incubation.
The claims cover methods for graphene functionalization using specified covalent and non-covalent molecules and conditions that preserve electronic properties, enable sequential graphene or 2D material attachment, and facilitate nanoparticle deposition, particularly oxides, with UV activation for attachment.
Stated Advantages
High degree of functionalization without deterioration of graphene's electrical properties, achieving over three orders of magnitude improvement in sheet resistance at low temperatures compared to plasma functionalization.
Synthesis of high mobility functionalized graphene samples (around 3000 cm2/Vs at low temperature) with p-doping effect compensating natural n-type doping in monolayer graphene.
Functionalization approach enables covalent one-step attachment of ZnO nanoparticles and can be extended to a wide range of nanoparticles and chemical molecules compatible with functional groups.
Facilitates scaffolding for deposition of thin dielectric films on epitaxial graphene without impacting electronic properties, enabling applications such as RF field effect transistors and mixers.
The method allows attachment of biomolecules like peptides, proteins, DNA, or antibodies, supporting biosensing applications.
Functionalization can be extended to other two-dimensional materials such as boron nitride and transition metal dichalcogenides, enabling heterostructure formation with preserved properties.
Documented Applications
Modulation of graphene's electrical properties.
Deposition of nanoparticles such as oxides (e.g., ZnO, TiO2, FeO2, CuO), metals, and quantum dots on graphene.
Attachment of sequential graphene layers and other two-dimensional materials including boron nitride, MoS2, and phosphorene.
Development of quantum Hall resistance standards based on graphene technology.
Use in sensors to enhance selectivity and sensitivity.
Attachment of biomolecules for biosensing applications.
Deposition of thin dielectric films for devices like RF field effect transistors and mixers.
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