This study presents, for the first time, a piezoelectric nanogenerators (PENG) model based on the nitrogen-doped carbon nanotubes (N-CNTs) array and demonstrates the ability of N-CNT to convert external oscillations into electrical energy. Molybdenum was proved to be a preferred material for the upper electrode due to its high corrosion resistance and the formation of ohmic contact at the interface with N-CNT. It was shown the operation of the PENG model in constant and pulsed modes. It was found that the output voltage of the PENG model increased linearly from 3 to 60 mV with an increase in the amplitude of the external mechanical influence from 3.5 to 95 μm and decreased from 54 to 26 mV with an increase in the frequency of external influence from 15 to 120 Hz due to an excess of the natural resonant frequency of the nanotubes. The experiments demonstrated that the power density of the N-CNT-based PENG model reached 12.63 μV/cm2. It was exhibited that the PENG model can be used not only as a nanogenerator for autonomous power supply of wearable electronic devices, but also as a highly sensitive deformation sensor. In addition, the clamping force of the upper electrode determines the frequency range of the PENG model. The obtained results open wide opportunities for practical application of vertically aligned N-CNTs for autonomous power supply of wearable electronic devices.

Development of a nitrogen-doped carbon nanotube nanogenerator for mechanical energy harvesting
    Abstract
    1 Introduction
    2 Experimental part
        2.1 Model making
        2.2 Measuring stand
    3 Results and discussion
        3.1 Characterization of the N-CNT sample
        3.2 Influence of the upper electrode material on the value of the output parameters
        3.3 Effect of the amplitude and frequency of the external influence on the output parameters
        3.4 Research into stability of the PENG model
    4 Conclusion
    Acknowledgements 
    References

• M. V. Il‵ina(Institute of Nanotechnologies, Electronics and Equipment Engineering, Southern Federal University, Taganrog, Russian Federation) Corresponding author
• O. I. Soboleva(Research Laboratory of Functional Nanomaterials Technology, Southern Federal University, Taganrog, Russian Federation) Corresponding author
• M. R. Polyvianova(Research Laboratory of Functional Nanomaterials Technology, Southern Federal University, Taganrog, Russian Federation)
• N. N. Rudyk(Research Laboratory of Functional Nanomaterials Technology, Southern Federal University, Taganrog, Russian Federation)
• D. N. Khomlenko(Research Laboratory of Functional Nanomaterials Technology, Southern Federal University, Taganrog, Russian Federation)
• O. I. Il‵in(Research Laboratory of Functional Nanomaterials Technology, Southern Federal University, Taganrog, Russian Federation)
• I. V. Pankov(Institute of Physical and Organic Chemistry, Southern Federal University, Rostov‑on‑Don, Russian Federation)