Piezoelectric Effect in PENG: Opposite Phase Output Signals with Polarity Reversal

According to the piezoelectric theory, it can be concluded that when a piezoelectric device is subjected to force, it generates electrical output signals. These signals will have opposite phases when the electrodes of the device are connected in different polarities to the testing equipment. This characteristic is evident in the electrical signal output features shown in Figure 3e-f and Figure S10. \n\nThe detailed optimization analysis of the addition of different mass ratios to PVDF's A-titanium dioxide, AR-titanium dioxide, and R-titanium dioxide is presented in Figure S11-13. Both forward and reverse connection tests are conducted, and in both cases, the electric output signals exhibit opposite phases. This indicates that the detected output is generated by the piezoelectric effect of the piezoelectric film in the PENG.