Graphene Quantum Dots: Syntheses, Applications, Sustainability, and Industrial Challenges

Jean-Jacques Gaumet

Université de Lorraine, LCP-A2MC, EA4632, F-57070, Metz, France

Graphene quantum dots (GQDs) are new fascinating carbon nanomaterials that are attracting particular interest due to their exceptional features and their potential use in many applications. GQDs emerged about 15 years ago with very fascinating traits such as a non-zero band gap, biocompatibility and tunable characteristics making them very competitive with usual organic dyes and heavy metals-based quantum dots. GQDs display chemical inertness, low photobleaching, low cytotoxicity, wavelength-tunable luminescence, electronic conductivity and a large surface area. As a consequence, GQDs are useful in many applications such as biosensors, solar cells, electrochemical devices, optical sensors and energy storage/conversion devices [1]. Non-exhaustively, the use of GQDs can be extend to the medical sector, the environmental remediation applications [2-3]. However, to date, none of these applications reached the industrial level since there is still no chemical process allowing to prepare GQDs at a large scale and low costs and in a sustainable approach [4].

In this talk, we will firstly review the different methods to produce GQDS and the versatile uses of that new material. Then, in a context of scale-up necessary for moving to a wider utilization, we have developed a sustainable approach to synthesize GQDs at the multigram scale from various biomass wastes (e.g., banana peels, date pits, orange peels, compost...) that are abundant in our modern society. Our procedure affords GQDs with good homogeneity (in terms of size, chemical constitution and photophysical properties). The GQDs show excitation-dependent photoluminescence ranging from blue to orange emission wavelength in solution. Interestingly, dry films of pure GQDs display white light emission under UV excitation, while aggregation-induced quenching is usually observed in the solid state, opening the way toward OLED applications.

References

[1] a) A. Ghaffarkhah, E. Hosseini, M. Kamkar, A. A. Sehat, S. Dordanihaghighi, A. Allahbakhsh, C. Van Der Kuur, M. Arjmand, Small, 2020, 210268; b) Y. Yan, J. Gong, J. Chen, Z. Zeng, W. Huang, K. Pu, J. Liu, P. Chen, Adv. Mater. 2019, 31, 1808283.

[2] M. H. M. Facure, R. Schneider, L. A. Mercante, D. S. Correa, Environ. Sci. Nano, 2020,7, 3710-3734.

[3] V. Kansara, S. Tiwari, Mitali Patel, Colloids and Surfaces B: Biointerfaces, 2022, 217, 112605.

[4] B Lyu, H.J. Li, F. Xue, L. Sai, B. Gui, D. Qian, X. Wang, J. Yang, Chem. Eng. J. 2020, 388, 124285.