Graphene Film Production via Molten Metal Substrate Phase Transition
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Solution Overview
Problem
Current methods for producing high-quality graphene films often result in unwanted surface topography such as wrinkles and ripples due to thermodynamic instability and differences in thermal expansion coefficients between the metal substrate and graphene, which affect mechanical, electronic, and chemical properties.
Innovation Solution
A continuous method involving a roll-to-roll system where a metal substrate is heated to form a molten metal layer, contacted with a carbon source gas to form a graphene layer, and then solidified, reducing surface imperfections and enhancing the quality of the graphene film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If continuous roll-to-roll production methods are used to manufacture graphene, then production cost is reduced and productivity is improved, but surface topography quality deteriorates due to wrinkles and ripples
Solution Approach 1:
The patent changes the physical state parameter of the metal substrate from solid to liquid (molten) during the graphene growth process. By heating the copper substrate above its melting point (1085°C), the metal transitions to a liquid state, which fundamentally alters the growth dynamics and suppresses ripple formation while maintaining continuous production capabilities
Solution Approach 2:
The patent utilizes phase transition of the metal substrate (solid→liquid→solid) as a core mechanism. The copper substrate is melted during graphene deposition and then rapidly solidified afterward. This phase transition process eliminates thermal expansion coefficient differences between substrate and graphene, thereby preventing ripple formation and improving surface topography quality
2Ease of manufacture
If standard CVD methods are used on solid metal substrates, then manufacturing process is simple, but surface topography deteriorates due to thermal expansion coefficient differences between substrate and graphene
Solution Approach 1:
The patent changes the temperature parameter beyond the normal CVD range by melting the metal substrate. This extreme temperature parameter change (above melting point) transforms the substrate state and eliminates the thermal expansion mismatch problem that causes ripples in conventional CVD processes
Solution Approach 2:
The patent introduces a phase transition step (melting and solidification of metal substrate) that is not present in standard CVD. This phase transition resolves the thermal expansion coefficient difference issue by ensuring both substrate and graphene experience the same thermal history, thereby preventing ripple formation
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 produces high-quality, large surface area graphene films with reduced surface topography, improving mechanical, electronic, and chemical properties while lowering production costs.
Implementation Method 1
heating the metal substrate to form a molten metal layer on a first surface of the metal substrate
Implementation Method 2
contacting the molten metal layer with a carbon source gas, such as a gas comprising hydrocarbon, to form a graphene-comprising layer
Implementation Method 3
solidifying the molten metal layer
Data Source
AI summary
A continuous method for manufacturing graphene films using a metal substrate, wherein a first surface of the metal substrate is heated such that a top layer of the first surface melts to form a molten metal layer, and devices for carrying out the same.