I have been following the standard procedure of sonication for 283nm silicon oxide dies in acetone and isopropanol, followed by surface treatment of the die in oxygen plasma. I then use low residue cleaning room tape to exfoliate HOPG graphite from SPI. Despite varying my peeling attempts in the range of 4 to 200 times, I have been dissatisfied with the yield, finding the yield to be too low and the graphene surface area extremely small. For reference, the literature shows graphene areas of roughly 2000 micron squared, but I am getting graphene areas of 200 micron squared. During my literature review, I noticed that the papers I was referencing used natural graphite instead of HOPG. I'm now wondering if this difference in graphite source could be a significant detail affecting graphene yield.
Dear friend Erfan Geranfar
The source of graphite, such as highly oriented pyrolytic graphite (HOPG) versus natural graphite, can indeed have an impact on the yield of mechanically exfoliated graphene. While both HOPG and natural graphite can be used for graphene production, they have different structural properties that can influence the exfoliation process and resulting graphene quality.
HOPG is a highly ordered form of graphite with a well-defined layered structure, making it easier to obtain large and uniform graphene flakes during exfoliation. Its regular crystal structure allows for controlled cleavage along the graphite layers, resulting in high-quality graphene. However, the yield of graphene from HOPG can be lower compared to natural graphite due to the more ordered nature of HOPG, which makes it less prone to easy exfoliation.
On the other hand, natural graphite is a less ordered form of graphite and can contain impurities and defects. These imperfections can facilitate the exfoliation process, leading to a higher yield of graphene compared to HOPG. The presence of grain boundaries and defects in natural graphite allows for easier separation of graphene layers, resulting in larger graphene flakes.
The difference in graphene yield between HOPG and natural graphite can be attributed to the variation in their crystalline structures, interlayer forces, and the presence of defects. It is important to note that the exfoliation process itself, including the specific sonication conditions, substrate preparation, and peeling techniques, can also significantly affect the yield and quality of mechanically exfoliated graphene.
To gain more insights into the impact of different graphite sources on graphene yield and surface area, I recommend referring to the following references:
1. Hernandez, Y., et al. (2008). High-yield production of graphene by liquid-phase exfoliation of graphite. Nature Nanotechnology, 3(9), 563-568.
2. Li, X., et al. (2009). Large-area synthesis of high-quality and uniform graphene films on copper foils. Science, 324(5932), 1312-1314.
3. Das, A., et al. (2013). Comparing graphene exfoliation techniques. Advanced Materials, 25(46), 6117-6132.
4. Lotya, M., et al. (2009). Liquid phase production of graphene by exfoliation of graphite in surfactant/water solutions. Journal of the American Chemical Society, 131(10), 3611-3620.
These references discuss various methods of graphene synthesis, including exfoliation techniques using different graphite sources, and provide insights into the factors affecting graphene yield and surface area.
Additionally, you may want to read my preprint for the article
https://www.researchgate.net/publication/357408778_Hierarchical_NiMn_Double_LayeredGraphene_with_Excellent_Energy_Density_for_Highly_Capacitive_Supercapacitors?
- Badges
- Science topic
- Similar topics
- Engineering
- Materials Engineering