  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.
