Nanostructural adsorption of vanadium oxide on functionalized graphene: a DFT study

Area of Science:

• Materials Science
• Nanotechnology
• Computational Chemistry

Background:

• Vanadium oxide (VO2) nanocrystals exhibit rutile-monoclinic phase transitions relevant to applications.
• Understanding the adsorption and growth mechanisms of VO2 on graphene substrates is crucial but theoretically unexplored.

Purpose of the Study:

• To theoretically investigate the adsorption and growth mechanisms of VO2 nanocrystals on graphene-based substrates.
• To determine binding energies and predict growth directions for VO2 nanostructures on pure and functionalized graphene.

Main Methods:

• Density Functional Theory (DFT) calculations were employed.
• Investigated adsorption on various sites of pure graphene (top, bridge, hollow) and functionalized graphene nanoribbons (epoxy, alcohol, carboxylate).
• Analyzed charge density maps, electronic local potentials, and partial density of states (PDOS).

Main Results:

• VO2 nanostructures prefer physical adsorption on hollow sites of pure graphene and chemical adsorption on carboxylate sites of functionalized graphene nanoribbons (FGNRs).
• Charge transfer mechanisms were elucidated through charge density maps.
• Rutile VO2 showed vertical growth tendencies, while M1-monoclinic VO2 exhibited horizontal growth tendencies.

Conclusions:

• The study provides insights into the controlled and oriented growth of VO2 nanocrystals on graphene.
• Findings facilitate the development of VO2-based applications, such as light regulation utilizing the metal-insulator transition (MIT).