How to use high-energy ion irradiation to create nanoporous graphene
|Graphene has remarkable physical and chemical properties, and one of its most exciting potentials lies in the development of nanoporous graphene—graphene embedded with tiny, nanometer-sized pores, which can be engineered for a variety of applications. A way to create a controlled distribution of nanopores in graphene is through high-energy ion beam irradiation (with energies ranging from 1–10 MeV), even if at these energies only tiny nanopores are predicted to form.
The study of defect formation and nanopore morphology at these higher energies is crucial for controlling the size, distribution, and number of defects in graphene, which affects their properties, and functionality. That’s why Dr Kristina Tomić Luketić, Dr Andreja Gajović and Dr Marko Karlušić (Ruđer Bošković Institute, in Zagreb) used Raman Spectroscopy to study the changes in morphology of single-layered supported graphene sheets irradiated by iodine, copper, silicon, and oxygen ions in the MeV energy range at the ToF-ERDA instrument, available at the CERIC Croatian Partner Facility.
Interestingly, an inverse correlation was observed: as ion velocity increases, the size of the nanopores decreases. Additionally, scientists discover that damage accumulation is heavily influenced by electronic stopping (that happens when ions deposit their energy to the electronic subsystem of the target): in cases where it dominates over nuclear stopping (in which energy deposition occur through elastic collisions with the target nuclei) by two orders of magnitude, graphene experiences substantial defect formation.
The findings coming from this systematic investigation enalble custom-made production of nanoporous graphene using high-energy heavy ion beam for a variety of applications, including the development of nanomembranes for gas separation, sensors, or even separators Li-ion batteries and supercapacitors.
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