Efficiency of piezoelectric materials

[ryanuser]

I was told that "piezoelectric materials can become more efficient if they were made to reduce their elasticity (the ones such as PVDF films that are flexiable).This is because the external energy is used to force the film back to its original shape just like when a spring is squashed; so most of the mechanical energy is stored and then released instead of being transformed to electricity. The internal efficiency of the materials is actually about 40% but because the energy is used to push the film back to its original shape reduces the efficiency to about 2%." (The material here is assumed to be in form of a thin screen printed film sensor).

To what extend is this true? Would Polyvinylidene fluoride (PVDF) films become more efficient if they were made so that they were less elastic?
Please leave comments for further elaborations.

Thanks

 

[Bystander]

https://en.wikipedia.org/wiki/Q_factor