title: Investigating the surface state of graphene quantum dots.
abstract: A universal route to GQDs is developed based on "solution phase-based scissor" methods. The PL centers of the GQDs are systematically studied and are proved to be the surface state. This is related to the hybridization structure of the edge groups and the connected partial graphene core. Through experiment and analysis, we have preliminarily proved that the efficient edge groups for green emission are mainly carboxyl, carbonyl and amide. This is indicated by the following three factors: firstly, the PL of GQDs is enhanced by UV exposure, during which partial -OH groups are converted into carboxyl groups; secondly, the PL properties of GQDs can be further improved by one-step solvothermal treatment, in which partial carboxyl groups are converted to amide groups and the surface state of the GQDs is enhanced; thirdly, reduced m-GQDs possess more -OH groups compared with reduced GQDs, resulting in more blue PL centers (the carboxyl, carbonyl and amide-based green centers are converted to -OH-based blue centers). The present work highlights a very important direction for the understanding of the PL mechanism of GQDs and other related carbon-based materials.
authors: State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, China. byangchem@jlu.edu.cn.
authors: Shoujun
authors: S
authors: Zhu
authors: Jieren
authors: J
authors: Shao
authors: Yubin
authors: Y
authors: Song
authors: Xiaohuan
authors: X
authors: Zhao
authors: Jianglin
authors: J
authors: Du
authors: Lei
authors: L
authors: Wang
authors: Haiyu
authors: H
authors: Wang
authors: Kai
authors: K
authors: Zhang
authors: Junhu
authors: J
authors: Zhang
authors: Bai
authors: B
authors: Yang