Influence of the Activation Time on the Piezoelectric Properties of Nitrogen-Doped Carbon Nanotubes

At present, there is an increasing need to create energy-efficient power supplies for wearable devices. In recent studies, we found that nitrogen-doped carbon nanotubes (N-CNTs), which exhibit anomalous piezoelectric properties, can be used as the basis for such devices. This paper presents the results of studying the effect of the activation time of catalytic centers during the growth of carbon nanotubes on the value of their piezoelectric strain coefficient and the value of the generated current. It is found that with an increase in the activation time of catalytic centers from 1 to 30 min, the value of the piezoelectric strain coefficient decreases from 19.78 to 4.49 pm/V, which is associated with a change in the geometric dimensions of the catalytic centers and, consequently, the structure of the N-CNTs. The results obtained can be used to create energy-efficient piezoelectric nanogenerators.