Hello.
I have some strange problem during large area CVD polycrystalline graphene transfer by using polymer(polycarbonate(PC)).
When I rinsed PC+graphene on SiO2 to remove PC, the graphene was dissolved in acetone....
I know it looks strange but some times it did not happen, many times...
Also, when I do same thing with microscale, small graphene, it never happened.
It does not look like graphene itself was dissolved in acetone.
Maybe, it was polycrystalline, large size (few mm scale).
So if I put strain on grapehen, the graphene could be removed with PC?
I changed the time and temperature of annealing process to make good contact between substrate and transferred graphen, but It did not work.
Only with Polycrystalline, large size grapehen(not just graphene. Many other semi materials also), and some time it was fine, sometimes not.
Thank you for listening.
Dear friend Seunghyo Park
Alright, let's dive into this graphene mystery with my spirit. Now, graphene, the superhero of the materials world, dissolving in acetone? That's a head-scratcher, but let's unravel this enigma.
Firstly, acetone is a fairly benign solvent when it comes to graphene. It shouldn't dissolve it easily. But, in the world of large-scale, polycrystalline graphene transfers, things might get a bit unpredictable.
Here are some musings:
1. **Contaminants**: Check for contaminants. Anything on the graphene layer, be it residues from the transfer process or impurities, could react with acetone in weird ways.
2. **Strain-induced Delamination**: You Seunghyo Park mentioned strain. Large, polycrystalline graphene might have more areas susceptible to delamination under strain. If there are microscopic defects or weak points, strain could cause the graphene to lift off or disintegrate.
3. **Transfer Quality**: Large-area transfers are tricky. Even a slight imperfection in the transfer process could leave weak points. If the graphene isn’t uniformly adhered to the substrate, it might behave unpredictably during the acetone rinse.
4. **Annealing**: Annealing is your ally, but it's a tricky one. The temperature and time need to be just right to ensure a good bond between graphene and the substrate. Too little, and you Seunghyo Park might not get a strong bond; too much, and you Seunghyo Park might introduce defects or weaken the interface.
5. **Polycrystalline Structure**: Polycrystalline structures might have grain boundaries that behave differently under stress or during chemical interactions. These boundaries could be more susceptible to dissolution.
6. **Time Variability**: The variability you're seeing could be due to subtle changes in the transfer process—humidity, temperature, even minute differences in the graphene itself.
Remember, we're venturing into the realms of material science where the nuances can be quite intricate. It might be worth consulting with peers in your field, running controlled experiments, and, if all else fails, maybe even giving your graphene a stern talking-to. After all, I dont shy away from a challenge!
My coming publication might be of your interest:
Preprint Hierarchical NiMn Double Layered/Graphene with Excellent Ene...
It seems like you are experiencing some variability in the dissolution of graphene during the transfer process using polycarbonate (PC) as a polymer support. This phenomenon occurs inconsistently, with the dissolution happening sometimes but not always.
One possibility could be the presence of impurities or defects in the polycrystalline graphene film. These defects could make the graphene more susceptible to dissolution in acetone. Additionally, the large size of the polycrystalline graphene grains might lead to a higher likelihood of defects, making it more prone to dissolution. Another potential factor could be the strain or stress applied during the transfer process. If there is significant strain on the graphene film, it could cause the wea adhesion between the PC and the graphene, resulting in the dissolution of the graphene when immersed in acetone.
To overcome this issue, you can consider the following suggestions:
- Optimize the surface treatment of the SiO2 substrate before the transfer process to ensure good adhesion between the substrate and the polycarbonate graphene film.
- Investigate alternative support materials with higher mechanical strength and chemical stability that are compatible with the transfer process.
- Implement a two-step transfer process, where an additional layer or bonding step is introduced to enhance the adhesion between the polycarbonate support and the graphene film.
- Explore different solvents for the rinsing step to find one that does not dissolve the polycarbonate or the graphene film.
- Perform additional characterization techniques, such as Raman spectroscopy, to evaluate the quality and structural integrity of the transferred graphene films.
It is important to note that graphene transfer processes can be intricate and highly dependent on several parameters. Therefore, it might require some experimentation and optimization to achieve consistent and reliable results.
Seunghyo Park The phenomenon you're experiencing, where large-area CVD polycrystalline graphene dissolves in acetone during the transfer process with PC, is indeed unusual and requires further investigation.
The graphene dissolution issue in acetone rinses can be attributed to incomplete polymer removal, adsorption of impurities, graphene defects, strain-induced detachment, and solvent intercalation. The film should be analyzed, transfer processes optimized, CVD growth controlled, and surface energy investigated.
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