Piezoelectric materials (that includes all pyroelectrics and ferroelectrics) are used by industry in a very large range of applications. These include ultrasonic detectors, cleaners, imaging systems and sonar devices; ink-jet printer heads, diesel and gasoline fuel injectors for automobiles, trucks and vans; electronic memory devices such as Ferroelectric RAM; micro and nano positioning actuators, valves, motors, and translators; RF filters, resonators, and VCOs; among many other applications.
There are many excellent books and reviews detailing the significance of this class of material – which can be polymer or ceramic; in bulk and thin film form; as 1D nano rods or wires to nanotubes and may also be processed as quantum dots. The properties of the materials have been shown, in some cases, to be dependent on their scale and dimension (as with many nanoscale material in fact) and perhaps, more importantly, the properties are highly non-linear with regards excitation voltage, mechanical stress and temperature. These factors make the development of measurement good practice and ultimately setting that down into documentary standards rather difficult.