Single and double carbon vacancies in pyrene as first models for graphene defects: A survey of the chemical reactivity toward hydrogen

Author(s)

Nieman, Reed ; Das, Anita ; Aquino, Adelia J. A. ; Amorim, Rodrigo G. ; Machado, Francisco B. C. ; Lischka, Hans

• Document type: Journal article
• Source: Chemical Physics; v. 482, p. 9-pg., 2017-01-12.

Abstract

Graphene is regarded as one of the most promising materials for nanoelectronics applications. Defects play an important role in modulating its electronic properties and also enhance its chemical reactivity. In this work the reactivity of single vacancies (SV) and double vacancies (DV) in reaction with a hydrogen atom Hr is studied. Because of the complicated open shell electronic structures of these defects due to dangling bonds, multireference configuration interaction (MRCI) methods are being used in combination with a previously developed defect model based on pyrene. Comparison of the stability of products derived from C-H-r, bond formation with different carbon atoms of the different polyaromatic hydrocarbons is made. In the single vacancy case the most stable structure is the one where the incoming hydrogen is bound to the carbon atom carrying the dangling bond. However, stable C-H-r bonded structures are also observed in the five-membered ring of the single vacancy. In the double vacancy, most stable bonding of the reactant Hr atom is found in the five-membered rings. In total, C-H-r bonds, corresponding to local energy minimum structures, are formed with all carbon atoms in the different defect systems and the pyrene itself. Reaction profiles for the four lowest electronic states show in the case of a single vacancy a complex picture of curve crossings and avoided crossings which will give rise to a complex nonadiabatic reaction dynamics involving several electronic states. (C) 2016 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 15/50018-9 - High-level quantum chemical investigations of defect structures in model graphene systems
• Grantee: Francisco Bolivar Correto Machado
• Support Opportunities: Regular Research Grants
• FAPESP's process: 14/24155-6 - Study of electronic states in polycyclic aromatic hydrocarbons and their properties as models of electronic graphene structures
• Grantee: Francisco Bolivar Correto Machado
• Support Opportunities: Regular Research Grants