Tuning flexoelectricty and electronic properties of zig-zag graphene nanoribbons by functionalization
arXiv:2009.06948 · doi:10.1016/j.carbon.2020.09.028
Abstract
The flexoelectric and electronic properties of zig-zag graphene nanoribbons are explored under mechanical bending using state of the art first principles calculations. A linear dependence of the bending induced out of plane polarization on the applied strain gradient is found. The inferior flexoelectric properties of graphene nanoribbons can be improved by more than two orders of magnitude by hydrogen and fluorine functionalization (CH and CF nanoribbons). A large out of plane flexoelectric effect is predicted for CF nanoribbons. The origin of this enhancement lies in the electro-negativity difference between carbon and fluorine atoms, which breaks the out of plane charge symmetry even for a small strain gradient. The flexoelectric effect can be further improved by co-functionalization with hydrogen and fluorine (CHF Janus-type nanoribbon), where a spontaneous out of plane dipole moment is formed even for flat nanoribbons. We also find that bending can control the charge localization of valence band maxima and therefore enables the tuning of the hole effective masses and band gaps. These results present an important advance towards the understanding of flexoelectric and electronic properties of hydrogen and fluorine functionalized graphene nanoribbons, which can have important implications for flexible electronic applications.
9 pages, 8 figures. To appear in Carbon
References in corpus (9)
- Energy Gaps in Graphene Nanoribbons
- Control of graphene's properties by reversible hydrogenation
- Evidence of structural strain in epitaxial graphene layers on 6H-SiC(0001)
- Atomically-Precise, Custom-Design Origami Graphene Nanostructures
- Quantum Flexoelectricity in Low Dimensional Systems
- Intrinsic bending flexoelectric constants in two-dimensional materials
- First-principles study of mechanical and electronic properties of bent monolayer transition metal dichalcogenides
- High flexoelectric constants in Janus transition-metal dichalcogenides
- Exploration of mechanical, thermal conductivity and electromechanical properties of graphene nanoribbon springs