Graphene Liquid Cell Assembly Without Polymer Transfer Films
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Solution Overview
Problem
Current methods for fabricating graphene liquid cells (GLCs) suffer from poor reproducibility and contamination issues due to the use of polymer support films, which hinder high-resolution, dynamic imaging of biological processes.
Innovation Solution
A method for fabricating GLCs using loop-assisted transfer (LAT) of graphene, which eliminates the need for polymer support films and induces minimal stress on the graphene, thereby improving the integrity and flexibility of the graphene films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polymer support films are used in GLC fabrication, then graphene can be supported through the sample assembly procedure, but polymer support films leave trace contaminations visible during TEM imaging and reduce graphene flexibility
Solution Approach 1:
The invention extracts and removes the polymer support film from the GLC fabrication process, transferring graphene directly onto the TEM grid without polymer intermediaries. This eliminates polymer trace contaminations while maintaining graphene integrity through a simplified assembly procedure.
Solution Approach 2:
The invention introduces water as a temporary intermediary medium to facilitate graphene transfer and assembly. Graphene is manipulated and positioned using water-based techniques, allowing support-free assembly that prevents polymer contamination while ensuring reliable graphene placement.
2Stability of the object's composition
If multilayer graphene is used, then superior stability is achieved, but the graphene is more rigid and often contaminated by preparation procedures
Solution Approach 1:
The invention extracts and eliminates the need for multilayer graphene stacking procedures that cause contamination. By using single-layer graphene with water-based assembly techniques, the method achieves stable GLC formation without the rigidity and contamination issues associated with multilayer preparation.
Solution Approach 2:
The invention changes the assembly parameters from mechanical stacking of multiple layers to a water-based single-layer transfer process. This parameter change maintains the stability needed for GLC formation while avoiding the contamination and rigidity problems of multilayer preparation.
3Ease of manufacture
If the scooping method is used to transfer graphene, then assembly is achieved, but mechanical stress is induced to the free-floating graphene film
Solution Approach 1:
The invention replaces the mechanical scooping action with a water-based transfer mechanism. Graphene is transferred and assembled using water flow and surface tension forces rather than mechanical contact, eliminating stress induction while maintaining effective assembly capability.
4Quantity of substance
If silicon-based liquid cells are used, then water can be confined between membranes, but significant electron scattering is induced through the SiN and water
Solution Approach 1:
The invention uses ultra-thin graphene films (single atomic layer) as confining shells instead of thicker SiN membranes. This reduces the total path length for electron transmission from approximately 100nm in SiN cells to just 0.34nm in graphene, dramatically reducing electron scattering while maintaining effective water confinement.
Data Source
AI summary
A thin film liquid cell suitable for transmission electron microscopy at room temperature is fabricated as follows. A thin film floating on a liquid is prepared. A droplet of the liquid with the thin film floating thereon is transferred to a support by means of a loop. The loop carries the droplet and the droplet carries the thin film during this transfer. Sufficient liquid from the droplet on the support is removed to form the thin film liquid cell.