Progress on the Applications of Piezoelectric Materials in Sensors

Piezoelectric materials, which can couple electrical and mechanical displacements, are one of the most important functional materials nowadays. They comprises piezoelectric monocrystals, piezoelectric polycrystals (piezoelectric ceramics), piezoelectric polymers, and piezoelectric composites. Sensors made of these materials can convert pressure, acceleration, flow rate, etc. to surface charge (voltage) that can be easily processed, and at the same time generate their own energy instead of consuming it. Compared to other electromechanical transduction technologies, piezoelectric sensors have the advantages of high environmental and chemical stability, broad temperature and frequency band, as well as self-sufficiency. Piezoelectric materials can also be used in various applications such as energy harvesters, actuators, transducers, and capacitors. This paper reviews the piezoelectric materials and their recent application progress on sensors and others. These published results show the developing trend of piezoelectric sensors to become lead-free, flexible, and with high performance.