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Improvement of the piezoelectricity of PVDF-TrFE by carbon black

In order to prepare PVDF-TrFE films with high piezoelectric performance, carbon black (CB), in the range of 0.0 wt% to 0.8 wt%, was added into PVDF-TrFE/DMF solutions. To investigate the effects of CB on the power generation capability, various fabricated films were attached on a vibrating plate, and then the output voltages and harvested power density were measured. The composite film was optimized with a calibrated open circuit voltage of 10.09 V when the CB content was at 0.8 wt%, which was about 79% higher than that of the pure PVDF-TrFE films (5.63 V). Meanwhile, the energy harvesting capability was enhanced by 164%. Fourier transform infrared spectroscopy and other characterization techniques show that the addition of CB resulted in the easier formation of β-phase (piezoelectric) rather than α-phase (non-piezoelectric) due to the nucleate role of CB during the preparation process of the composite films.