Graphene Bilayer Transfer Lamination for Clean Substrate Integration
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Solution Overview
Problem
The challenge of transferring graphene cleanly onto various substrates without residual metal residues or defects such as wrinkles or holes remains unsolved, hindering the full utilization of graphene's potential in diverse applications.
Innovation Solution
A method involving the application of continuous and discontinuous polymer layers to a graphene-metal bilayer, followed by selective etching and laminating, allows for the successful transfer of graphene to substrates, including medical devices, by using PMMA, PVA, PI, PET, and PEN polymer layers and etchants like acetone and water.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If CVD is used to grow graphene on metal catalysts, then graphene can be produced at scale, but residual metal and etching residues remain on the graphene
Solution Approach 1:
The patent segments the transfer process into multiple distinct steps: applying first and second polymer layers to opposite sides of the graphene-metal bilayer, selective etching of each polymer layer through perforations in discontinuous polymer layers, and sequential removal of sacrificial layers. This segmentation allows precise control over metal removal while preserving graphene integrity, resolving the contradiction between scalable production and clean transfer.
Solution Approach 2:
The patent introduces polymer layers (PMMA, PVA) and discontinuous polymer layers (PI, PET, PEN) as intermediary materials between the graphene-metal bilayer and the substrate. These intermediaries facilitate controlled metal removal through selective etching while protecting the graphene during transfer, enabling clean graphene transfer that maintains the benefits of scalable CVD production.
2Loss of time
If transfer methods are simplified, then processing time is reduced, but defects such as wrinkles or holes appear in the graphene
Solution Approach 1:
The patent applies polymer layers and creates perforations in discontinuous polymer layers before the actual metal removal process. This preliminary preparation establishes controlled pathways for etchant delivery and ensures uniform polymer distribution, enabling rapid selective etching without causing graphene defects like wrinkles or holes.
Solution Approach 2:
The patent uses discontinuous polymer layers with arrays of perforations that act as porous structures to control etchant flow. These perforations enable rapid and uniform delivery of etchants to the polymer layers, accelerating the metal removal process while maintaining precise control over the etching front, thus preventing graphene defects.
3Manufacturing precision
If selective etching is performed through discontinuous polymer layers, then metal removal is precise, but multiple layers and steps increase process complexity
Solution Approach 1:
The patent applies different polymer materials (PMMA, PVA) with distinct etching characteristics to opposite sides of the graphene-metal bilayer, and creates localized perforation patterns in discontinuous polymer layers (PI, PET, PEN). This local differentiation enables selective etching of metal through controlled pathways, achieving precise metal removal while the systematic arrangement of layers keeps the overall process manageable.
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
Enables clean and efficient transfer of graphene onto substrates, facilitating large-scale production and integration into electronic devices, particularly in medical devices like catheters, with reduced defects and metal residues.
Implementation Method 1
The first etching step includes selectively etching the first continuous polymer layer with a first etchant through the first discontinuous polymer layer, thereby removing the first sacrificial layer and reexposing the face of the graphene layer
Implementation Method 2
The second etching step includes selectively etching the second continuous polymer layer with a second etchant through the second discontinuous polymer layer, thereby removing the second sacrificial layer and reexposing the face of the metal layer
Implementation Method 3
The laminating step includes laminating the substrate by pressing the face of the graphene layer into a surface of the substrate
Data Source
AI summary
Methods for transferring graphene to substrates include at least a method for transferring a graphene-metal bilayer to a substrate to form a laminate thereof. The method can include applying a first continuous polymer layer to a graphene layer of the graphene-metal bilayer; applying a first discontinuous polymer layer to the first continuous polymer layer; applying a second continuous polymer layer to a metal layer of the graphene-metal bilayer; applying a second discontinuous polymer layer to the second continuous polymer layer; etching the first continuous polymer layer with a first etchant through the first discontinuous polymer layer; laminating the substrate by pressing the face of the graphene layer into a surface of the substrate; etching the second continuous polymer layer with a second etchant through the second discontinuous polymer layer, thereby transferring the graphene-metal bilayer to the substrate to form the laminate.