Scale Effects of Low-Dimensional Relaxor Ferroelectric Single Crystals and Their Application in Novel Pyroelectric Infrared Detectors

摘要

Pyroelectric devices exhibit great advantages of wide wavelength response, uncooled operation, high sensitivity, compact structures and very low cost, which enable a variety of applications such as temperature sensing, flame and fire detection, gas monitoring, energy harvesting, night vision, and thermal imaging. Traditional pyroelectric materials, including triglycine sulfate (TGS), lithium tantalite (LiTaO_3) and barium strontium titanate (BST) have been utilized for detector applications, but their deliquescent properties, low pyroelectric coefficient or needing bias voltage and thermostatic apparatus could not meet the demand of high-end applications. Since large size single crystals of (1-x)Pb(Mg_(1/3)Nb_(2/3))O_3-xPbTiO_3 (PMN-xPT) were successfully grown by modified Bridgman technique, the corresponding studies on microstructure-properties relation, composition/ orientation dependent performances of this system have been extensively carried out. In particular, superior performances of ultra-high pyroelectric coefficient, high Curie temperature and relative low dielectric loss have been observed, indicating their capabilities to the next-generation advanced pyroelectric devices.