Structure, bandgap and photoluminescence of fluorinated reduced graphene oxide

Fluorinated graphene has been widely studied and its nonstoichiometric structure is considered as defective. However, the impact of structural defects on optical properties was generally neglected. Here, fluorinated reduced graphene oxide (F-rGO) was prepared by annealing rGO and XeF2, and its structure, bandgap and optical properties are investigated. The results show that there are plenty of vacancies modified by CF2 on the basal plane of F-rGO sheets. With the increasing of the fluorine concentrations from 0.29 to 0.98 at.%, F-rGO exhibits broad tunable gap from 0.42 to 3.0 eV. Interestingly, it shows obviously band-tail absorption and broader PL emission peak due to the fluorinated vacancies. Theoretical calculations show that CF2 group on C mono-vacancy can increase the bandgap. This study provides a new insight into the bandgap opening and PL emission in F-rGO. [Display omitted] •Fluorinated reduced graphene oxide exhibits tunable bandgap from 0.42 to 3.0 eV.•Fluorinated reduced graphene oxide exhibits vacancies modified by CF2.•Vacancies modified by CF2 lead to band-tail absorption.•Fluorinated reduced graphene oxide shows broader PL emission peak.•Theoretical calculations show that CF2 group on C vacancy can increase the bandgap.