title: Gram-scale synthesis of single-crystalline graphene quantum dots with superior optical properties.
abstract: Graphene quantum dots (GQDs) have various alluring properties and potential applications, but their large-scale applications are limited by current synthetic methods that commonly produce GQDs in small amounts. Moreover, GQDs usually exhibit polycrystalline or highly defective structures and thus poor optical properties. Here we report the gram-scale synthesis of single-crystalline GQDs by a facile molecular fusion route under mild and green hydrothermal conditions. The synthesis involves the nitration of pyrene followed by hydrothermal treatment in alkaline aqueous solutions, where alkaline species play a crucial role in tuning their size, functionalization and optical properties. The single-crystalline GQDs are bestowed with excellent optical properties such as bright excitonic fluorescence, strong excitonic absorption bands extending to the visible region, large molar extinction coefficients and long-term photostability. These high-quality GQDs can find a large array of novel applications in bioimaging, biosensing, light emitting diodes, solar cells, hydrogen production, fuel cells and supercapacitors.
authors.affiliation: Institute of Nanochemistry and Nanobiology, Shanghai University, Shanghai 200444, P.R. China.
authors.forename: Liang
authors.initials: L
authors.lastname: Wang
authors.affiliation: Institute of Nanochemistry and Nanobiology, Shanghai University, Shanghai 200444, P.R. China.
authors.forename: Yanli
authors.initials: Y
authors.lastname: Wang
authors.affiliation: SEU-FEI Nano-Pico Center, Key Laboratory of MEMS of Ministry of Education, School of Electronic Science and Engineering, Southeast University, Nanjing 210096, P.R. China.
authors.forename: Tao
authors.initials: T
authors.lastname: Xu
authors.affiliation: Institute of Nanochemistry and Nanobiology, Shanghai University, Shanghai 200444, P.R. China.
authors.forename: Haobo
authors.initials: H
authors.lastname: Liao
authors.affiliation: Institute of Nanochemistry and Nanobiology, Shanghai University, Shanghai 200444, P.R. China.
authors.forename: Chenjie
authors.initials: C
authors.lastname: Yao
authors.affiliation: Institute of Nanochemistry and Nanobiology, Shanghai University, Shanghai 200444, P.R. China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Shanghai Applied Radiation Institute, Shanghai University, Shanghai 200444, P.R. China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Li
authors.affiliation: Shanghai Applied Radiation Institute, Shanghai University, Shanghai 200444, P.R. China.
authors.forename: Zhiwen
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Institute of Nanochemistry and Nanobiology, Shanghai University, Shanghai 200444, P.R. China.
authors.forename: Dengyu
authors.initials: D
authors.lastname: Pan
authors.affiliation: SEU-FEI Nano-Pico Center, Key Laboratory of MEMS of Ministry of Education, School of Electronic Science and Engineering, Southeast University, Nanjing 210096, P.R. China.
authors.forename: Litao
authors.initials: L
authors.lastname: Sun
authors.affiliation: Shanghai Applied Radiation Institute, Shanghai University, Shanghai 200444, P.R. China.
authors.forename: Minghong
authors.initials: M
authors.lastname: Wu