Is the Chain of Oxidation and Reduction Process Reversible in Luminescent Graphene Quantum Dots?
Small
; 11(31): 3773-81, 2015 Aug.
Article
em En
| MEDLINE
| ID: mdl-25925604
ABSTRACT
Graphene-based quantum dots (QDs) have received a tremendous amount of attention as a new type of light-emitting materials. However, their luminescence origins remain controversial due to extrinsic states of the impurities and disorder structures. Especially, the function of oxygen-contents should be understood and controlled as a crucial element for tuning the optical properties of graphene-based QDs. Herein, a series of graphene oxide QDs (GOQDs) with different amounts of oxygen-contents are first synthesized via a direct oxidation route of graphite nanoparticle and thoroughly compared with a series of reduced GOQDs (rGOQDs) prepared by the conventional chemical reduction. Irreversible emission and different carrier dynamics are observed between the GOQDs and rGOQDs, although both routes show a similar tendency with regard to the variation of oxygen-functional components. Their luminescence mechanisms are closely associated with different atomic structures. The mechanism for the rGOQDs can be associated with a formation of small sp(2) nanodomains as luminescent centers, whereas those of GOQDs may be composed of oxygen-islands with difference sizes depending on oxidation conditions surrounded by a large area of sp(2) bonding. Important insights for understanding the optical properties of graphene-based QDs and how they are affected by oxygen-functional groups are shown.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
Small
Assunto da revista:
ENGENHARIA BIOMEDICA
Ano de publicação:
2015
Tipo de documento:
Article
País de afiliação:
Coréia do Sul