title: Effect of Lateral Size of Graphene Quantum Dots on Their Properties and Application.
abstract: Well-defined graphene quantum dots (GQDs) are crucial for their biological applications and the construction of nanoscaled optoelectronic and electronic devices. However, as-synthesized GQDs reported in many works assume a very wide lateral size distribution; thus, their apparent properties cannot truthfully reflect intrinsic properties of the well-defined GQDs, and more importantly, the applications of GQDs will be affected and limited as well. In this work, we demonstrated that different sized GQDs with a narrow size distribution could be obtained via gel electrophoresis of the crude GQDs prepared through a photo-Fenton reaction of graphene oxide (GO). It is illustrated that the photoluminesce (PL) emissions of the well-defined GQDs originated mainly from the peripheral carboxylic groups and conjugated carbon backbone planes through fluorescence and UV-vis spectroscopies. More importantly, our findings challenge the notion that the excitation wavelength dependent PL property of the as-synthesized GQDs is the intrinsic property of the size-defined GQDs. Preliminary data at the cellular level indicated that the small sized GQDs exhibit weaker quenching DNA dye ability but higher toxicity to the cells compared to that of the as-synthesized GQDs. This discovery is essential to explore applications of the GQDs in pharmaceutics and to understand the origin of the optoelectronic properties of GQDs.
authors.affiliation: Department of Electronic Engineering, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University , Shanghai 200240, P. R. China.
authors.forename: Fangwei
authors.initials: F
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Bioreactor Engineering, Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology , Shanghai 200237, P. R. China.
authors.forename: Fei
authors.initials: F
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Bioreactor Engineering, Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology , Shanghai 200237, P. R. China.
authors.forename: Chong
authors.initials: C
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Bioreactor Engineering, Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology , Shanghai 200237, P. R. China.
authors.forename: Xiaozhen
authors.initials: X
authors.lastname: Xin
authors.affiliation: State Key Laboratory of Bioreactor Engineering, Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology , Shanghai 200237, P. R. China.
authors.forename: Jingyuan
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Electronic Engineering, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University , Shanghai 200240, P. R. China.
authors.forename: Shouwu
authors.initials: S
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Bioreactor Engineering, Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology , Shanghai 200237, P. R. China.
authors.forename: Jingyan
authors.initials: J
authors.lastname: Zhang
mesh_terms: D004587:Electrophoresis, Agar Gel; D006108:Graphite / Q000737:chemistry*; D006801:Humans; D049449:Luminescence; D061986:MCF-7 Cells; D010316:Particle Size; D045663:Quantum Dots / Q000737:chemistry* / Q000648:ultrastructure; D012996:Solutions; D013056:Spectrophotometry, Ultraviolet
chemical_list: D012996:Solutions; D006108:Graphite
keywords: gel electrophoresis; graphene quantum dot; lateral size; photoluminescence