Doping graphene by adsorption of polar molecules at the oxidized zigzag edges

TL;DR

This study theoretically explores how polar molecules like water and ammonia adsorb onto oxidized zigzag edges of graphene, enabling controllable p-doping by charge transfer influenced by molecular positioning.

Contribution

It introduces a theoretical framework for doping graphene via adsorption at oxidized edges, highlighting controllable charge transfer based on molecule type and placement.

Findings

Adsorbed molecules form clusters along oxidized edges due to oxygen interaction.

Graphene donates charge to adsorbates, affecting electronic properties.

p-doping can be gradually controlled by selecting appropriate adsorbates.

Abstract

We have theoretically investigated the electronic and magnetic properties of graphene whose zigzag edges are oxidized. The alteration of these properties by adsorption of $\mathrm{H_{2}O}$ and $\mathrm{NH_3}$ molecules have been considered. It was found that the adsorbed molecules form a cluster along the oxidized zigzag edges of graphene due to interaction with the electro-negative oxygen. Graphene tends to donate a charge to the adsorbates through the oxygen atoms and the efficiency of donation depends on the intermolecular distance and on the location of the adsorbed molecules relative to the plane of graphene. It was found that by appropriate selection of the adsorbates, a controllable and gradual growth of $p$-doping in graphene with a variety of adsorbed molecules can be achieved.