Outstanding Piezoelectric Sensitivity of Poly (Vinylidene-Trifluoroethylene) for Acceleration Sensor Application

As one type of the sensors, piezoelectric accelerometer may transform the acceleration signal into the electric signal, which are widely utilized for measurement, monitoring, or controlment. The mostly utilized piezoelectric materials are piezoelectric ceramics [e.g., PZT, ((1 –
x
)Pb(Mg
_1/3
Nb
_2/3
)O
₃
– xPbTiO
₃
) (PMN-PT)] for their large piezoelectric stress constant (
${d}_{{33}}$
). However, their high dielectric permittivity (
$\varepsilon _{r}$
) leads to the relatively small piezoelectric voltage constant (
${g}_{{33}}$
), thus the low response sensitivity. In an effort to meet the demand of sensors with high sensitivity, low weight, and small size, in this work, a series of poly(vinylidene-trifluoroethylene) (P(VDF-TrFE)) films are annealed at elevated temperature and fabricated into sensors. Thanks to its rather low permittivity, P(VDF-TrFE) sensor exhibits much larger
${g}_{{33}}$
and sensitivity than that of PMN-PT. Its sensitivity closely depends on the annealing temperature and film thickness. On a hand-made touch sensing instrument, about 10%–20% larger output voltage is obtained in P(VDF-TrFE) sensor than that of PMN-PT under the same stimulating force, although the thickness of P(VDF-TrFE) is only one twenty-fifth of PMN-PT. The results show the excellent piezoelectric sensing performance and great commercial potential of P(VDF-TrFE) for not only its excellent sensitivity but also the feasible processability for thin film in large scale.