Graphene Foil Production via Iterative Layer Transfer
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Solution Overview
Problem
Current methods for producing graphene with a pre-defined number of layers are limited, as CVD growth on metallic substrates is self-limited to one layer, and transferring multiple layers onto elastic polymer substrates is uncontrolled and inefficient, often requiring rigid substrates that can be damaged and limiting further applications.
Innovation Solution
A method involving CVD graphene deposition on a metallic substrate, followed by transfer onto a polymer substrate, where the graphene/polymer stack is iteratively processed to achieve a pre-defined number of layers, allowing for the production of graphene foil with multiple layers on any flat substrate, reducing the number of iterations and substrate damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If CVD growth is performed on Cu substrate, then graphene layer quality is improved, but the number of layers is limited to one layer only
Solution Approach 1:
The process is segmented into distinct stages: first growing high-quality monolayer graphene on Cu substrate, then transferring it to PMMA substrate, and repeating the process to build up multiple layers. This segmentation allows each layer to be grown with optimal quality while achieving the desired number of layers through iterative transfer.
Solution Approach 2:
A PMMA layer is deposited on the Cu substrate before graphene growth. This preliminary action enables subsequent detachment and transfer of the graphene layer while preserving its quality, allowing the same Cu substrate to be reused for growing additional layers.
2Quantity of substance
If multiple graphene layers are transferred onto rigid substrates such as optical glass or quartz, then layer assembly is achieved, but substrate damage occurs and further transfer is limited
Solution Approach 1:
PMMA (polymethyl methacrylate) is used as a flexible polymer substrate instead of rigid glass or quartz. This flexible substrate can be repeatedly deformed and manipulated during the transfer process without damage, enabling multiple iterations of graphene layer assembly while maintaining substrate integrity.
Solution Approach 2:
The substrate material is changed from rigid (glass/quartz) to flexible polymer (PMMA). This parameter change in substrate properties allows the substrate to withstand repeated mechanical manipulation during transfer operations, preventing damage and enabling iterative layer assembly.
3Quantity of substance
If layer-by-layer transfer method is used, then multiple graphene layers are obtained, but the number of iterations increases and preparation time extends
Solution Approach 1:
Multiple graphene layers are grown simultaneously on separate Cu substrates, then transferred together onto a single PMMA substrate in one operation. This merging approach reduces the number of iterative transfer cycles needed, significantly decreasing preparation time compared to transferring one layer at a time.
Solution Approach 2:
Multiple graphene layers are pre-grown on Cu substrates before the transfer step. This preliminary preparation allows all layers to be ready for simultaneous transfer, eliminating the need for sequential growth and transfer operations, thus reducing total preparation time.
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 rapid production of graphene foil with a controlled number of layers, expanding application possibilities and reducing preparation time compared to traditional layer-by-layer transfer methods, while allowing for transfer onto various substrates and maintaining high layer quality.
Implementation Method 1
CVD graphene deposited on a metallic substrate
Implementation Method 2
a polymer layer, in particular a polymethyl methacrylate (PMMA) layer, is deposited on the graphene surface
Data Source
Figure 1a~1b
Figure 2
Figure 3~4
AI summary
The present invention relates to a production method of graphene foil with a pre-defined number of graphene layers covering the following stages: a) producing graphene on a metallic substrate; b) depositing a polymer layer on the graphene surface; c) separating the polymer/graphene stack from the metallic substrate characterized in that subsequently it comprises stages as follows: d) transferring the obtained polymer/graphene stack directly onto the metallic substrate with at least one graphene layer deposited on top; e) separating the polymer/graphene/graphene stack from the metallic substrate.