title: Spectroscopic Investigation of Plasma-Fluorinated Monolayer Graphene and Application for Gas Sensing.
abstract: Large-area monolayer fluorinated graphene (FG) is synthesized by a controllable SF6 plasma treatment. The functional groups of FG are elucidated by various spectroscopies, including Raman spectroscopy, X-ray photoemission spectroscopy (XPS), and near edge X-ray absorption fine structure (NEXAFS) spectroscopy. Raman results suggest that the defects are introduced into the monolayer graphene during the fluorination process. The fluorine content can be varied by the plasma treatment and can reach the maximum (∼24.6 atom % F) under 20 s of plasma treatment as examined by XPS measurement. The angle-dependent NEXAFS results reveal that the fluorine atoms interact with the graphene matrix to form covalent C-F bonds, which are perpendicular to the basal plane of FG. FG is applied as a gas-sensing material and owns much better performance for ammonia detection compared to pristine graphene. On the basis of our density functional theory simulation results, the fast response/recovery behavior and high sensitivity of the FG gas sensor are attributed to enhanced physical absorption due to the C-F covalent bonds on the surface of FG.
authors.affiliation: Jiangsu Key Laboratory for Carbon Based Materials and Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University , Suzhou, Jiangsu 215123, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Jiangsu Key Laboratory for Carbon Based Materials and Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University , Suzhou, Jiangsu 215123, China.
authors.forename: Liwei
authors.initials: L
authors.lastname: Fan
authors.affiliation: Jiangsu Key Laboratory for Carbon Based Materials and Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University , Suzhou, Jiangsu 215123, China.
authors.forename: Huilong
authors.initials: H
authors.lastname: Dong
authors.affiliation: Jiangsu Key Laboratory for Carbon Based Materials and Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University , Suzhou, Jiangsu 215123, China.
authors.forename: Pingping
authors.initials: P
authors.lastname: Zhang
authors.affiliation: Jiangsu Key Laboratory for Carbon Based Materials and Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University , Suzhou, Jiangsu 215123, China.|Advanced Light Source, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
authors.forename: Kaiqi
authors.initials: K
authors.lastname: Nie
authors.affiliation: Jiangsu Key Laboratory for Carbon Based Materials and Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University , Suzhou, Jiangsu 215123, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Zhong
authors.affiliation: Jiangsu Key Laboratory for Carbon Based Materials and Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University , Suzhou, Jiangsu 215123, China.
authors.forename: Youyong
authors.initials: Y
authors.lastname: Li
authors.affiliation: Advanced Light Source, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
authors.forename: Jinghua
authors.initials: J
authors.lastname: Guo
authors.affiliation: Jiangsu Key Laboratory for Carbon Based Materials and Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University , Suzhou, Jiangsu 215123, China.
authors.forename: Xuhui
authors.initials: X
authors.lastname: Sun
keywords: NEXAFS; ammonia; fluorination; gas sensor; graphene