Photoluminescence mechanism in graphene quantum dots: Quantum confinement effect and surface/edge state

• Published in: Nano today 2017-04, Vol.13, p.10-14
• Main Authors: Zhu, Shoujun, Song, Yubin, Wang, Joy, Wan, Hao, Zhang, Yuan, Ning, Yang, Yang, Bai
• Format: Article
• Language: English
• Subjects: Carbon dots; Graphene quantum dots; Photoluminescence mechanism; Quantum confinement effect; Surface state
• ISSN: 1748-0132; 1878-044X
• DOI: 10.1016/j.nantod.2016.12.006

[Display omitted] GQDs can be prepared by cutting different carbon resources or carbonization from small molecules or polymers. The dominant photoluminescence mechanism of GQDs contained quantum confinement effect of conjugated π-domains, surface/edge state in GQDs as well as the synergistic effect of these two factors. •The synthesis of GQDs can be divided into “top-down” splitting methods and “bottom-up” organic approaches.•Both quantum confinement effect of conjugated π-domains and surface/edge state exist in GQDs.•The surface state also contains triplet carbenes at the zigzag edges, attached chemical groups, surface defects, heteroatom doping in carbon lattice, and giant red-edge effect. As a new class of fluorescent carbon materials, graphene quantum dots (GQDs) have drawn increasing attention due to their outstanding properties and potential applications. Herein, GQDs prepared by chemical synthetic strategies, which mainly contain cutting different carbon resources and carbonization from small molecules or polymers, are discussed. Although the photoluminescence (PL) mechanism of GQDs can be explained by the size of the GQDs, surface chemical groups, and doping atoms, there is no universal agreement on the specific PL mechanism. The dominant PL mechanism of GQDs consists of the quantum confinement effect of conjugated π-domains, the surface/edge state in GQDs, as well as the synergistic effect of these two factors.