Energy-level structure of nitrogen-doped graphene quantum dots

The doping of carbon-based materials is of great importance due to its ability to modulate their optical, electrical and optoelectronic properties. Nitrogen-doped graphene quantum dots (N-GQDs) have received significant attention due to their superior electrocatalytic activity, optical properties and biocompatibility. The energy-level structure of N-GQDs remains unknown, which hinders the development of N-GQDs for various applications. Here, we report a one-pot synthesis method to prepare large-quantity N-GQDs at room temperature and atmospheric pressure under a prolonged reaction time. Using this approach, we can effectively dope N into the N-GQDs. As revealed by electron energy loss spectroscopy, N-doping introduces a new energy level into the electronic structure, which is responsible for tuning the optical properties of the N-GQDs.

[1]  SonBinh T. Nguyen,et al.  Aqueous Suspension and Characterization of Chemically Modified Graphene Sheets , 2008 .

[2]  Yi Lin,et al.  Electrochemical Tuning of Luminescent Carbon Nanodots: From Preparation to Luminescence Mechanism , 2011, Advanced materials.

[3]  Yang Liu,et al.  One-step ultrasonic synthesis of fluorescent N-doped carbon dots from glucose and their visible-light sensitive photocatalytic ability , 2012 .

[4]  Hyun Joon Shin,et al.  Nitrogen-doped graphene for high-performance ultracapacitors and the importance of nitrogen-doped sites at basal planes. , 2011, Nano letters.

[5]  M. Oehzelt,et al.  Nitrogen-doped graphene: efficient growth, structure, and electronic properties. , 2011, Nano letters.

[6]  Li Xueming,et al.  Bottom-up synthesis of large-scale graphene oxide nanosheets , 2012 .

[7]  Mukul Kumar,et al.  Tailoring the field emission property of nitrogen-doped carbon nanotubes by controlling the graphitic/pyridinic substitution , 2010 .

[8]  Gui Yu,et al.  Synthesis of N-doped graphene by chemical vapor deposition and its electrical properties. , 2009, Nano letters.

[9]  Lin Shao,et al.  Catalyst-free synthesis of nitrogen-doped graphene via thermal annealing graphite oxide with melamine and its excellent electrocatalysis. , 2011, ACS nano.

[10]  Kai Xiao,et al.  n-Type field-effect transistors made of an individual nitrogen-doped multiwalled carbon nanotube. , 2005, Journal of the American Chemical Society.

[11]  Jianhua Hao,et al.  Deep ultraviolet photoluminescence of water-soluble self-passivated graphene quantum dots. , 2012, ACS nano.

[12]  Liangti Qu,et al.  Nitrogen-doped graphene quantum dots with oxygen-rich functional groups. , 2012, Journal of the American Chemical Society.

[13]  C. N. R. Rao,et al.  Synthesis, Structure, and Properties of Boron‐ and Nitrogen‐Doped Graphene , 2009, 0902.3077.

[14]  Identification of electron donor states in N-doped carbon nanotubes , 2000, cond-mat/0011318.

[15]  Guonan Chen,et al.  Blue luminescent graphene quantum dots and graphene oxide prepared by tuning the carbonization degree of citric acid , 2012 .

[16]  Liang Li,et al.  N‐Doped Graphene‐SnO2 Sandwich Paper for High‐Performance Lithium‐Ion Batteries , 2012 .

[17]  S. M. Mominuzzaman,et al.  Nitrogen doping and structural properties of amorphous carbon films deposited by pulsed laser ablation , 2002 .

[18]  M. Antonietti,et al.  Phosphorus-doped carbon nitride solid: enhanced electrical conductivity and photocurrent generation. , 2010, Journal of the American Chemical Society.

[19]  M. Antonietti,et al.  A detailed view on the polycondensation of ionic liquid monomers towards nitrogen doped carbon materials , 2010 .

[20]  J. J. Lander,et al.  Low‐Energy Electron Diffraction Study of Graphite , 1964 .

[21]  Lipeng Zhang,et al.  Mechanisms of Oxygen Reduction Reaction on Nitrogen-Doped Graphene for Fuel Cells , 2011 .

[22]  B. Alemán,et al.  Transfer-free batch fabrication of large-area suspended graphene membranes. , 2010, ACS nano.

[23]  Hui‐Ming Cheng,et al.  Synthesis and upconversion luminescence of N-doped graphene quantum dots , 2012 .

[24]  Lufeng Yang,et al.  One-step preparation of nitrogen-doped graphene quantum dots from oxidized debris of graphene oxide. , 2013, Journal of materials chemistry. B.

[25]  Sang Ouk Kim,et al.  Highly efficient vertical growth of wall-number-selected, N-doped carbon nanotube arrays. , 2009, Nano letters.

[26]  Y. Kawazoe,et al.  Spin and band-gap engineering in doped graphene nanoribbons , 2008 .

[27]  Richard W. Siegel,et al.  Selective Attachment of Gold Nanoparticles to Nitrogen-Doped Carbon Nanotubes , 2003 .

[28]  C Durkan,et al.  Single Crystals of Single-Walled Carbon Nanotubes Formed by Self-Assembly , 2001, Science.

[29]  Lei Fu,et al.  Synthesis of Nitrogen‐Doped Graphene Using Embedded Carbon and Nitrogen Sources , 2011, Advanced materials.

[30]  R. Asahi,et al.  Optically Tunable Amino‐Functionalized Graphene Quantum Dots , 2012, Advanced materials.

[31]  Y. Liu,et al.  Nitrogen-doped graphene as efficient metal-free electrocatalyst for oxygen reduction in fuel cells. , 2010, ACS nano.

[32]  P. Ajayan,et al.  Synthesis of nitrogen-doped graphene films for lithium battery application. , 2010, ACS nano.

[33]  Li Xueming,et al.  Size‐Dependent Structural and Optical Characteristics of Glucose‐Derived Graphene Quantum Dots , 2013 .

[34]  Minghong Wu,et al.  Hydrothermal Route for Cutting Graphene Sheets into Blue‐Luminescent Graphene Quantum Dots , 2010, Advanced materials.

[35]  B. K. Gupta,et al.  Graphene quantum dots derived from carbon fibers. , 2012, Nano letters.

[36]  L. Dai,et al.  Nitrogen-doped colloidal graphene quantum dots and their size-dependent electrocatalytic activity for the oxygen reduction reaction. , 2012, Journal of the American Chemical Society.

[37]  Yanglong Hou,et al.  Facile preparation of nitrogen-doped few-layer graphene via supercritical reaction. , 2011, ACS applied materials & interfaces.

[38]  Z. Lei,et al.  Structural evolution and electrocatalytic application of nitrogen-doped carbon shells synthesized by pyrolysis of near-monodisperse polyaniline nanospheres , 2009 .