Comparisons between bare carbon (CPs) and nitrogen-doped carbon nanoparticles (N-CPs) synthesised using hydrothermal reaction are carried out. It was found that hydrothermal reaction of citric acid yields graphene-like sheets, while the nitrogen doping using ethylenediamine resulted in amorphous polymeric ball-like hydrocarbons devoid of any aromatic rings. Although the Fourier transform infrared spectroscopy, Raman spectroscopy and nuclear magnetic resonance spectroscopy indicate the presence of carbon–carbon double bonds (C=C), and the ground states of both materials are very deep (> 7.8 eV) as measured by ultraviolet photoelectron spectroscopy. This indicates the conjugation is very short. This is supported by the fact that both materials are UV blue emitting peaking at 375 nm probably originating from C=C.

Structural, chemical and electronic differences between bare and nitrogen-doped carbon nanoparticles
    Abstract
    1 Introduction
    2 Experimental
        2.1 Materials
        2.2 Synthesis of bare carbon and N-doped carbon nanoparticles
        2.3 Characterisations
        2.4 Results and discussion
    3 Conclusions
    Acknowledgements 
    References

• H. L. Lee(Nanomaterials Research Group, School of Chemical Sciences, Universiti Sains Malaysia)
• K. L. Woon(Department of Physics, Low Dimensional Materials Research Centre, University of Malaya)
• S. Tan(Nanomaterials Research Group, School of Chemical Sciences, Universiti Sains Malaysia)
• W. S. Wong(Department of Physics, Low Dimensional Materials Research Centre, University of Malaya)
• A. Ariffin(Department of Chemistry, University of Malaya)
• N. Chanlek(Synchrotron Light Research Institute)
• H. Nakajima(Synchrotron Light Research Institute)
• T. Saisopa(NANOTEC‑SUT Center of Excellence on Advanced Functional Nanomaterials and School of Physics, Suranaree University of Technology)
• P. Songsiriritthigul(NANOTEC‑SUT Center of Excellence on Advanced Functional Nanomaterials and School of Physics, Suranaree University of Technology)