The intrinsic negative Poisson’s ratio effect at the level of molecule in two-dimensional nanomaterials, especially in the perfect planar nanostructures with a single atom thickness, is really rare and has attracted a lot of research interests because of its unique mechanical properties in the nanoscale and extensive applications in mechanical nanodevices. In this work, a novel ideal planar carbon nanostructure (PCNS) framework with a single atom thickness composed by carbon and hydrogen atoms is proposed and studied by means of first-principles density functional calculation. The results showed that the PCNS is, simultaneously, of excellent thermodynamic, molecular dynamic and mechanical stabilities. In addition, the electronic structure, mechanical characters, and optical-electronic characteristics of PCNS are also explored. Excitedly, it is found that the PCNS has a significant negative Poisson’s ratio effect in plane, and the maximum value of Poisson’s ratio is as high as − 2.094. Meanwhile, the material has a wide range of elastic mechanics. Moreover, the PCNS presents an ideal UV absorption performance. It is hoped that this work could be a useful structural design strategy for the development of the ideal 2D carbon-based nanomechanical devices with the intrinsic negative Poisson’s ratio effect and other electronic functions.

    Abstract
        Graphic abstract
    1 Introduction
    2 Computational methods
    3 Results and discussions
        3.1 Geometry and stability of PCNS
        3.2 Mechanical properties of PCNS
        3.3 Electronic structures of PCNS
        3.4 Optical and electronic properties
    4 Conclusions
    Acknowledgements 
    References

• Kun Yuan(School of Chemical Engineering and Technology, Key Laboratory for New Molecule Materials Design and Function of Gansu Universities, Tianshui Normal University)
• Yaoxiao Zhao(Institute for Chemical Physics, School of Chemistry, State Key Laboratory of Electrical Insulation and Power Equipment, Xi’an Jiaotong University)
• Mengyang Li(Institute for Chemical Physics, School of Chemistry, State Key Laboratory of Electrical Insulation and Power Equipment, Xi’an Jiaotong University)
• Yanzhi Liu(School of Chemical Engineering and Technology, Key Laboratory for New Molecule Materials Design and Function of Gansu Universities)