Piezoelectric Effect in PENG: Opposite Phases of Electric Output Signals with Electrode Polarity

Based on the piezoelectric theory, it can be inferred that when a piezoelectric device is subjected to force, the electric output signals will exhibit opposite phases depending on the polarities of the electrodes connected to the testing equipment. This characteristic is evident in the electrical signal output features depicted in Figure 3e-f and Figure S10. A detailed optimization analysis of incorporating different mass ratios of A-titanium dioxide, AR-titanium dioxide, and R-titanium dioxide into PVDF is presented in Figure S11-13. Both forward and reverse connection tests demonstrate that the electric output signals display opposite phases, indicating that the detected output is produced by the piezoelectric effect of the piezoelectric film in the PENG.