Functionalised Graphene Oxide for Stable Electronic Dispersions
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Solution Overview
Problem
Current methods for producing graphene sheets are substrate-specific, require high temperature processes, and result in unstable, ion-dependent dispersions unsuitable for electronic applications, limiting their scalability and flexibility for use in electronic devices.
Innovation Solution
Controlled oxidation of graphite to form sub-stoichiometric graphene oxide, followed by surface functionalization with solubilizing groups to create stable, high-concentration dispersions in organic or water-based solvents, allowing for room temperature deposition on various substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If mechanical exfoliation or epitaxial growth methods are used to produce graphene sheets, then single-layer and few-layer graphene can be obtained, but the methods are substrate-specific and require high temperature post-anneal steps
Solution Approach 1:
The patent changes the chemical parameters of graphene by oxidizing it to graphene oxide, which fundamentally alters its solubility and processing characteristics. This allows graphene to be processed in solution at room temperature rather than requiring high-temperature epitaxial growth on specific substrates
Solution Approach 2:
Graphene oxide serves as an intermediary form between graphite and functionalized graphene. The oxidation process creates a soluble intermediate that can be processed in solution, and subsequent reduction restores the conductive properties while maintaining the solution-processable advantage
2Manufacturing precision
If high temperature processes are used to produce graphene sheets, then crystallinity and structure can be improved, but the application to organic electronic devices is limited
Solution Approach 1:
The patent changes the thermal parameters by replacing high-temperature thermal annealing with chemical oxidation and reduction processes that occur at room temperature or mild heating conditions, enabling compatibility with organic electronic devices
Solution Approach 2:
The patent substitutes thermal energy with chemical energy by using chemical oxidants and reductants to achieve the structural transformations that previously required high-temperature thermal processes
3Quantity of substance
If graphite oxide is used to produce graphene dispersions, then exfoliation can be achieved, but the dispersions are unstable and ion-dependent
Solution Approach 1:
The patent creates composite structures by functionalizing graphene oxide with organic molecules, creating a composite material that combines the exfoliation benefits of graphene oxide with the stability and solubility benefits of the organic functional groups
Solution Approach 2:
The patent applies local functionalization to specific sites on the graphene oxide surface, adding functional groups at strategic locations to provide both steric stabilization and electrostatic repulsion, preventing aggregation without requiring high ion concentrations
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Achieves stable, high-concentration dispersions of graphene sheets that can be easily processed into thin films for electronic applications, enabling scalable and flexible use in electronic devices without the need for high-temperature processes or ion-rich environments.
Implementation Method 1
exfoliating and in-situ functionalising the graphite oxide surface
Implementation Method 2
functional groups which improve the solubility of the graphene oxide in organic solvents or water
Data Source
AI summary
A functionalised graphene oxide and a method of making a functionalized graphene oxide comprising: (i) oxidizing graphite to form graphite oxide wherein the graphene sheets which make up the graphite independently of each other have a basal plane fraction of carbon atoms in the sp2-hybridised state between 0.1 and 0.9, wherein the remainder fraction comprises sp3-hybridised carbon atoms which are bonded to oxygen groups selected from hydroxyl and/or epoxy and/or carboxylic acid; and (ii) exfoliating and in-situ functionalizing the graphite oxide surface with one or more functional groups such that fictionalization of the surface is effected at a concentration greater than one functional group per 100 carbon atoms and less than one functional group per six carbon atoms. The functionalized graphene oxide is dispersible at high concentrations in appropriate solvents without aggregating or precipitating over extended periods at room temperature.