Graphene Quantum Dots Derived from Carbon Fibers

Juan Peng†‡, Wei Gao§, Bipin Kumar Gupta†, Zheng Liu†, Rebeca Romero-Aburto†, Liehui Ge†, Li Song#, Lawrence B. Alemany§, Xiaobo Zhan†, Guanhui Gao†, Sajna Antony Vithayathil, Benny Abraham Kaipparettu, Angel A. Marti§, Takuya Hayashi+, Jun-Jie Zhu*‡, and Pulickel M. Ajayan*†§

^† Mechanical Engineering and Materials Science Department, Rice University, Houston, Texas 77005, United States

^‡ State Key Lab of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China

^§ Department of Chemistry, Rice University, Houston, Texas 77005, United States

 National Physical Laboratory (CSIR), Dr K S Krishnan Road, New Delhi 110012, India

 Department of Molecular Pathology, The University of Texas, MD. Anderson Cancer Center, Houston Texas 77054, United States

^# Research Center for Exotic Nanocarbons, Shinshu University, 4-17-1 Wakasato, Nagano 380-8553, Japan

 Institute of Materials Science and Engineering, Ocean University of China, Qingdao, 266003, P.R. China

 Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, United States

 Department of Chemistry and Bioengineering, Rice University, Houston, Texas 77005, United States

⁺ Faculty of Engineering, Shinshu University, 4-17-1 Wakasato, Nagano 380-8553, Japan

Nano Lett., Article ASAP

DOI: 10.1021/nl2038979

Publication Date (Web): January 4, 2012

Graphene quantum dots (GQDs), which are edge-bound nanometer-size graphene pieces, have fascinating optical and electronic properties. These have been synthesized either by nanolithography or from starting materials such as graphene oxide (GO) by the chemical breakdown of their extended planar structure, both of which are multistep tedious processes. Here, we report that during the acid treatment and chemical exfoliation of traditional pitch-based carbon fibers, that are both cheap and commercially available, the stacked graphitic submicrometer domains of the fibers are easily broken down, leading to the creation of GQDs with different size distribution in scalable amounts. The as-produced GQDs, in the size range of 1–4 nm, show two-dimensional morphology, most of which present zigzag edge structure, and are 1–3 atomic layers thick. The photoluminescence of the GQDs can be tailored through varying the size of the GQDs by changing process parameters. Due to the luminescence stability, nanosecond lifetime, biocompatibility, low toxicity, and high water solubility, these GQDs are demonstrated to be excellent probes for high contrast bioimaging and biosensing applications.