A 3D-printed, alternatively tilt-polarized PVDF-TrFE polymer with enhanced piezoelectric effect for self-powered sensor application

This work reports a 3D-printed PVDF-TrFE piezoelectric film (PF) coated with one pair of dislocated interdigital electrode (ID) to produce multiple, alternatively tilt-polarized regions in the cross-sectional area, which exhibits quite high sensitivity to an external stress stimulation. The theoretical analysis further reveals that the enhanced piezoelectric effect of the film can be attributed to the larger electric dipole moment due to tilt dipole orientation in PVDF-TrFE polymer. The experimental measurements show that the ID tilt-polarized PVDF-TrFE film (ID-TPPF) can produce a stable peak voltage of 73.5 V under dynamic compression stress of 50 kPa at 1 Hz, corresponding to a pressure sensitivity of 1.47 V/kPa, which are 14.7 times and 3.6 times those of a PVDF-TrFE film with conventional thickness-polarization and in-plane polarization, respectively. Correspondingly, the peak power density of ID-TPPF is as high as 478 μW/cm2, while at a load of 3 MΩ, the load power is still 207 μW/cm2, which even instantly lights up eight LEDs connected in series without using any charging capacitor. This work confirms that the 3D-printed ID-TPPF shows great potential in self-powered tactile sensors and artificial skin applications in the future.