Stone–Wales Defect and Vacancy-Assisted Enhanced Atomic Orbital Interactions Between Graphene and Ambient Gases: A First-Principles Insight

Abstract

Graphene has magnificent fundamental properties for its application in various fields. However, these fundamental properties have been observed to get perturbed by various agents like intrinsic defects and ambient gases. Degradation as well as p-type behavior of graphene under an ambient atmosphere are some of the properties that have not yet been explored extensively. In this work, interactions of different ambient gases, like N2, O2, Ar, CO2, and H2O, with pristine and defective graphene are studied using density functional theory (DFT) computations. It is observed that while the pristine graphene is chemically and physically inert with ambient gases, except for oxygen, its interaction with these ambient gases increases significantly in the presence of carbon vacancies and Stone–Wales (SW) defects. We report that Ar and N2 are apparently not inert with defective graphene, as they also influence its fundamental properties like band structure, mid gap (trap) states, and Fermi energy level. We have also found that while oxygen makes pristine graphene p-type, the phenomenon amplifies in the presence of SW defects. Besides, in the presence of carbon vacancies, N2, H2O, and CO2 also make the graphene monolayer p-type. Among ambient gases, oxygen is the real performance and reliability killer for graphene. Its reaction is seeded by a carbon vacancy, which initiates its degradation by local formation of graphene oxide.

A Roadmap for Disruptive Applications and Heterogeneous Integration Using Two-Dimensional Materials: State-of-the-Art and Technological Challenges

“…Notably, 2D TMDCs offer a plethora of sensing possibilities due to their ability to introduce physical defects (vacancy or interstitial) and create unique midgap states through chemical functionalization of the surface, which offers distinct electrical responses to a range of volatile organic compounds (VOCs). Among various 2D materials, graphene , and MoS 2 have been the most explored materials demonstrating their ability to sense a range of VOCs. A few groups have also demonstrated the sensing ability of WS2, WSe2, PtSe2, SnS2, h-BN, and phosphorene.…”

Ozone Decomposition on Defective Graphene: Insights from Modeling

“…37 Although the SW defect alone is stable, it is more reactive than the pristine sheet in bonding gaseous species. 48 Our results show that the SW defect lowers the O 3 chemisorption barrier to 0.58 eV (0.61 eV from the blue in Figure 3) compared to 0.97 eV on pristine graphene. By searching the possible reaction pathways (Figure 3), we find that there are two competing routes that lead to the ozonide formation (SW-2 or SW-2″).…”

“…Once the defect is formed under nonequilibrium conditions (e.g., rapid quenching from high temperature or under irradiation), the 5 eV barrier for the reverse transformation should warrant its stability at room temperature . Although the SW defect alone is stable, it is more reactive than the pristine sheet in bonding gaseous species . Our results show that the SW defect lowers the O 3 chemisorption barrier to 0.58 eV (0.61 eV from the blue in Figure ) compared to 0.97 eV on pristine graphene.…”

First-Principles Molecular Dynamics Insight into the Atomic Level Degradation Pathway of Phosphorene

“…Defects, especially point vacancies, are an integral part of any natural, synthesized, or grown material. Although phosphorous vacancy defect is relatively stable in phosphorene, 31 it may become critical in the presence of reactive gases, like other two-dimensional (2D) materials, 32 due to unsaturated phosphorous atoms near the vacant sites. To investigate this aspect, MD studies were performed after adding an oxygen molecule over the vacant site of the phosphorene surface ( Figure 10 a).…”