STUDY OF LEAD-FREE PYROELECTRIC CERAMICS FOR INFRARED SENSORS

Abstract

Pyroelectric ceramics are important functional materials that have been widely utilized for infrared sensors. Bi0.5Na0.5TiO3-based (BNT) ceramics are promising lead-free candidates for pyroelectric applications and also possess attractive piezoelectric and ferroelectric characteristics. In the present research, the significantly improved pyroelectric and piezoelectric performances were achieved by various ion doping strategies with the optimal pyroelectric coefficient higher than 600 𝜇C/m2K and d33 higher than 200 pC/N. In the meanwhile, the increasing doping content can drive BNT from ferroelectric to relaxor ferroelectric state due to the rising disordering level, and the material performances can be further improved by introducing a ferroelectric and relaxor coexisted state for reduced energy barrier. Moreover, a synthesis method of porous ceramics with controllable dielectric constant and enhanced FOMs was developed. This study suggest that BNT-based ceramics are promising candidates to provide tunable properties in replacing lead-containing materials for the relevant applications.