Monolayer MXene Delamination Using Mixed-Solvent Etching
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Solution Overview
Problem
When MAX phase is treated with hydrofluoric acid, an element A that bonds between MXenes remains, resulting in the generation of multilayer MXene that cannot be delaminated into a single layer, which affects the conductivity of thin films formed using these MXenes.
Innovation Solution
A method involving a treatment solution with a polar solvent, an organic solvent, and tetramethylammonium salt is used to remove the element A from MAX phase or multilayer MXene, thereby delaminating monolayer MXene.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If hydrofluoric acid is used to remove element A from MAX phase, then element A removal is achieved, but multilayer MXene that cannot be delaminated into single layer is generated
Solution Approach 1:
The patent changes the chemical parameters of the treatment solution by replacing pure hydrofluoric acid with a mixed solution containing hydrofluoric acid and organic solvent (such as dimethyl sulfoxide, dimethylformamide, or N-methyl-2-pyrrolidone). This parameter change modifies the interaction between the treatment solution and MAX phase, enabling effective element A removal while preventing multilayer aggregation, thus achieving both high delamination precision and reliable conductivity.
Solution Approach 2:
The patent creates a composite treatment solution by combining hydrofluoric acid with organic solvents. This composite approach leverages the etching capability of hydrofluoric acid while the organic solvent components prevent multilayer aggregation through their specific chemical properties, resulting in successful single-layer delamination and maintaining high conductivity.
2Quantity of substance
If element A remains between MXene layers, then multilayer MXene is formed, but preferable conductivity is not obtained
Solution Approach 1:
The patent modifies the treatment solution parameters by adding organic solvents to hydrofluoric acid, creating an optimized chemical environment that completely removes element A from between MXene layers. This complete removal eliminates the barrier to charge transport, achieving both high MXene yield and preferable conductivity.
3Ease of manufacture
If multilayer MXene is used to form thin film, then film formation is achieved, but preferable conductivity is not obtained
Solution Approach 1:
The patent changes the treatment solution composition to include organic solvents, which produce monolayer MXene that can be easily processed into thin films. The resulting films exhibit both ease of manufacture and preferable conductivity due to the single-layer structure and complete element A removal.
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
This method efficiently produces monolayer MXene, which can be used to form conductive thin films with reduced sheet resistance, achieving preferable conductivity.
Implementation Method 1
bringing a starting material containing MAX phase having a chemical formula of Mn+1AXn or multilayer MXene in which a plurality of monolayer MXenes having a chemical formula of Mn+1Xn are bonded to each other by an element A into contact with a treatment solution so as to remove the element A from the starting material
Implementation Method 2
a treatment solution containing a first solvent as a polar solvent, a second solvent as an organic solvent, and tetramethylammonium salt so as to remove the element A from the starting material to produce delaminated monolayer MXene
Data Source
AI summary
A method for generating MXene includes: bringing a starting material containing MAX phase 10 having a chemical formula of Mn+1AXn or multilayer MXene 16 in which a plurality of monolayer MXenes 20 having a chemical formula of Mn+1Xn are bonded to each other by an element A into contact with a treatment solution containing a first solvent as a polar solvent, a second solvent as an organic solvent, and tetramethylammonium salt so as to remove the element A from the starting material to produce delaminated monolayer MXene 20.