LAUSR

In this article, energy recovery based on PVDF doped with HfO2 is proposed. The free energy of CH2=CF2 is determined in different base with the B3LPY functional. The basis set LanL2DZ was chosen because it takes into account the atom of hafnium of atomic number $${\text{Z}} = 72$$ which exceeds the extension of some basis sets. In addition, LanL2DZ gives an accurate result and a reasonable computing time. The geometries of the molecules were optimized with B3LPY/LanL2DZ. The motivation of this study is the improvement of the optoelectronic, dielectric and piezoelectric properties of PVDF by introducing HfO2 into its matrix. We determined the parameters of $$\left( { {-} {\text{CH}}_{2} {-} {\text{CF}}_{2} {-} } \right)_{3} \cdot {\text{xHfO}}_{2}$$ and identified the effect of HfO2 on the PVDF. It appears that the permittivity of the modified PVDF increases. When the PVDF is doped once or twice, a fluorine atom is captured by the hafnium. The migration of fluorine towards HfO2 considerably favors the electric polarization of the molecule. It then results in an important dipole moment with a polar phase undoubtedly favored. Our results show that the molecule $$\left( { {-} {\text{CH}}_{2} {-} {\text{CF}}_{2} {-} } \right)_{3} \cdot {\text{HfO}}_{2}$$ is a good dielectric material ( $${\text{E}}_{\text{g}} = 5.90\;{\text{eV}}$$ ) and can be a good piezoelectric material. The electronic affinity of the modified PVDF is significantly higher than that of virgin PVDF. This demonstrates that HfO2-doped PVDF is more stable than virgin PVDF. The piezoelectric properties are significantly improved. The piezoelectric coefficient varies between 13.111 and 25.635 pC N−1 for the modified PVDF compared to $$11.979\;{\text{pC N }}^{-1}$$ for the virgin PVDF. In conclusion, HfO2 improves the dielectric, optoelectronic and piezoelectric properties of PVDF.