The Piezoelectric Sensing Properties of PAN/MoS<sub>2</sub> Flexible Composite Nanofiber Film
Authors: Zhang Hengbo  , Li Yinhui  , Li Weidong  , Gao Fei  , Yin Rongyan  , Liang Jianguo  , Zhao Peng  , Zhou Yunlei  , Li Pengwei  , Bian Guibin  ,   1 School of Electronic Information and Optical Engineering, Taiyuan University of Technology, Micro-Nano System Research Center, Taiyuan 030024, China;,   2 School of Integrated Circuits, Taiyuan University of Technology, Nano Energy and Devices, Taiyuan 030024, China;,   3 Hangzhou Institute of Technology, Xidian University, Hangzhou 311231, China
Published: February 2025

Flexible piezoelectric materials can convert mechanical energy into electrical energy to power micro/nano electronic devices. In recent years, research into piezoelectric technologies has revealed that molybdenum disulfide (MoS<sub>2</sub>) can enhance the piezoelectric properties of composite materials. This paper presents the fabrication of a PAN/MoS<sub>2</sub> flexible composite nanofiber film piezoelectric sensor via electrospinning. The influence of MoS<sub>2</sub> nanosheet content on the piezoelectric performance of the PAN/MoS<sub>2</sub> composite nanofiber films is systematically investigated, and the morphology and structure of the composite nanofiber films are characterized. The results show that MoS<sub>2</sub> is uniformly distributed in the composite nanofiber films, and the zigzag conformation of the PAN molecular was enhanced with the addition of MoS<sub>2</sub>. As the MoS<sub>2</sub> doping content increases, the performance of the PAN/MoS<sub>2</sub> composite nanofiber film sensor shows a trend of first increasing and then decreasing, reaching the maximum value when the MoS<sub>2</sub> content is 3.0 wt%. When the MoS<sub>2</sub> doping content increases from 0 wt% to 3.0 wt%, the open-circuit output voltage of the PAN/MoS<sub>2</sub> composite nanofiber film sensor increases from 1.92 V to 4.64 V, and the short-circuit output current increases from 1.03 μA to 2.69 μA. At 3.0 wt% MoS<sub>2</sub> doping, the maximum output power of the PAN/MoS<sub>2</sub> composite nanofiber film sensor reaches 3.46 μW, with an internal resistance of approximately 10 MΩ. The output voltage of the composite nanofiber film sensor increases with the applied external force. At a frequency of 10 Hz, when external forces of 2 N, 3 N, 4 N, 5 N, and 6 N are applied, the sensor output voltages are 2 V, 3.4 V, 5.9 V, 8.7 V, and 10.3 V, respectively. Compared with pure PAN, the piezoelectric constant <i>d<sub>33</sub></i> of the PAN/MoS<sub>2</sub> composite nanofiber film increases by 4.86 times. The PAN/MoS<sub>2</sub> composite nanofiber film sensor can efficiently charge commercial capacitors, and the discharged capacitors can successfully power a green LED. Additionally, it can monitor in real-time, under passive conditions, the bending state of the knee and the forward movement of the bicycle wheel during cycling. After 10,000 impact cycles, the PAN/MoS<sub>2</sub> composite nanofiber film sensor shows stable voltage output with no obvious fluctuations, demonstrating excellent stability. Overall, the PAN/MoS<sub>2</sub> flexible composite nanofiber film sensor exhibits outstanding flexibility, low cost, and self-powered capabilities, showing promising potential for applications in wearable/portable electronics, smart devices, and intelligent robotics.