Enhancement of nonvolatile polarization and pyroelectric sensitivity in Lithium tantalate (LT)/ Poly (vinylidene fluoride) (PVDF) nano composite

TL;DR

This study enhances pyroelectric sensitivity in LT/PVDF nanocomposites by increasing ferroelectric polarization at low fields, making them suitable for flexible, large-area pyroelectric sensors.

Contribution

The paper introduces LT/PVDF nanocomposite films that significantly improve ferroelectric polarization and pyroelectric sensitivity at lower poling fields compared to pure PVDF.

Findings

Ferroelectric polarization increased from 0.014 to 2.06 μC/cm² with LT volume fraction.

Pyroelectric voltage sensitivity improved from 3.93 V/J to 18.5 V/J.

Enhanced properties enable better pyroelectric sensors at lower poling fields.

Abstract

For pyroelectric sensor application, materials having large ferroelectric polarization at low applied field and high pyroelectric sensitivity are required. PVDF is one of the ferroelectric polymers, which is being used for pyroelectric detector application. Following properties of PVDF such as low density, low acoustic impedance, wide bandwidth, flexibility, toughness, and ease of fabrication into complex patterns and arrays make it suitable for large area detector applications. But the PVDF has low value of pyroelectric coefficient (p). High field (above 1200kV/cm) is required to pole the PVDF film. To reduce poling field and to get high value of ferroelectric polarization at low poling field, nano composite films of LT/PVDF have been prepared. Since LT is ferroelectric (max. poling field ~ 200kV/cm and (p) ~ 2.3 * 10-8 C cm-2/ K) in nature, the nonvolatile polarization of composite increased from 0.014microC/cm2 to 2.06microC/cm2 at an applied field of 150kV/cm as the volume fraction of LT (fLT) nano particle increases from 0.0 to 0.17. Similarly the increase of fLT from 0.0 to 0.17 results in increase of pyroelectric voltage sensitivity from 3.93 V/J to 18.5V/J.