Significantly enhanced ferroelectric and pyroelectric properties in polyvinylidene fluoride induced by shear force with spin-coating

Ferroelectric polymers are widely used in wearable energy conversion electronics for their favorable flexibility and pyroelectric properties, such as infrared sensors and energy harvesting devices. In this work, we report a method to greatly enhance the pyroelectric properties of polyvinylidene fluoride (PVDF) by spin-coating. Under the shear stress induced by spin-coating, the crystallization behavior of PVDF has been distinctly improved. As a result, the crystallinity and relative content of β phase achieve 40% and 97% in PVDF and the polarization reaches up to 28.2 µC/cm² at 80 MV/m². Consequently, the pyroelectric coefficient of spin-coated PVDF film has been raised to as high as 0.92 × 10⁻⁸ C/cm² K at 35 °C, which is significantly superior to those of cast PVDF film, stretched PVDF film, P(VDF-TrFE) film and the PVDF-PZT composite film. This achievement will enable the practically potential for PVDF based pyroelectric polymers in wearable infrared sensors and energy harvesting devices.