In a study published in Applied Physics Letters, researchers at Tohoku University introduced a mild fluorination method to address graphene’s zero-bandgap limitation.
Most electronic materials have a bandgap, or “gate,” that controls the flow of electricity by either allowing or blocking it. This mechanism enables the operation of devices like computers and smartphones. Graphene, however, lacks a bandgap, causing it to conduct electricity continuously and making it unsuitable for switching applications.
To overcome this, scientists have frequently added small amounts of fluorine atoms to graphene. This approach slightly alters its structure, creating a bandgap while retaining its key properties. However, conventional fluorination methods rely on toxic chemicals, making them hazardous and impractical for large-scale use.
We developed an environmentally friendly approach, one where we utilized fluoropolymers under controlled conditions to achieve selective fluorination. This advancement also enables enhanced photoluminescence and tunable transport properties while maintaining high carrier mobility, making graphene more applicable for use in optoelectronic and energy devices.
Dr. Yaping Qi, Assistant Professor, Tohoku University
The research team, led by Qi, used advanced techniques such as photoluminescence (PL) mapping and Raman spectroscopy to study how fluorination affects graphene’s structure and optical properties. Their experiments showed that fluorinated graphene exhibits improved light-emitting properties, making it a promising material for LEDs, sensors, and other energy-related technologies.
This work is also connected to developments in van der Waals (vdW) heterostructures, which involve stacking different 2D materials to achieve multifunctionality. These structures have potential applications in memory storage, artificial intelligence, and photoelectric devices.
The integration of fluorinated graphene into vdW heterostructures opens up exciting possibilities, especially for flexible electronics and systems that can perform multiple tasks at once.
Dr. Xichan Gao, Study Co-Author and Assistant Professor, Advanced Institute for Materials Research, Tohoku University
Qi added, “This research demonstrates how environmentally friendly processing can significantly improve the functional properties of graphene. Combining fluorination with strain engineering opens new possibilities for the development of scalable, high-performance 2D materials, providing a pathway to enhance graphene’s practical utility while maintaining a focus on safe and scalable material processing techniques.”
Journal Reference:
Xue, Y., et. al. (2024) Photoluminescence and transport properties of fluorinated graphene via a weak fluorination strategy. Applied Physics Letters. doi.org/10.1063/5.0197942
