Piezoelectric materials are found in a wide variety of applications as they can be used as components in both actuators and sensors. The industry standard and most commonly studied piezoelectric is Pb(Zr,Ti)O3 (PZT). A major concern in PZT is the lead, which puts manufacturing workers at risk and, introduces hazardous waste into the environment upon disposal of PZT-based components. The necessity for new piezoelectric materials clearly exists, but there is currently no good substitute for PZT. Many studies of PZT have led to a detailed understanding of how the crystal structure contributes to the enhanced properties, but little is known about the structures of its lead-free counter parts, slowing their development for use in applications. The aim of this study is to investigate the fundamental structure-property relationships in two key lead-free piezoelectric materials. The research provides a fundamental understanding that aids in the development of benign piezoelectric materials to improve the sustainability of electronic devices. This project is also strongly committed to expanding the opportunities available in student education and works to recruit and retain young scientists in science and engineering fields.
TECHNICAL DETAILS: This research advances the fundamental understanding of structure-property relationships in piezoelectric ceramics. The goal of this project is to assess the local distortions from the average structure of two well-known lead-free piezoelectric materials at their morphotropic phase boundary (MPB) and correlate the structural information to observations of the measured properties. Ba,Ca(Zr,Ti)O3, the most promising lead-free piezoelectric material to date, and BaTiO3-BiInO3, a system with a non-traditional MPB are being investigated. Systems are being studied both poled and unpoled to examine the structural changes under real conditions. These detailed structural studies utilize X-ray and neutron diffraction as well as EXAFS, with analysis using the Pair Distribution Function method and Reverse Monte Carlo modelling. In addition, this project aims to recruit and retain young scientists in STEM fields and train graduate students to excel in their careers. Graduate students are participating in the Lens of the Market® program to learn how to translate their sustainable research ideas to innovation with the purpose of solving market problems. Freshman and sophomore undergraduates will be given the opportunity to work in the lab and gain the early research experiences that result in increased retention in the STEM fields. High school women and minority students in the Summer Experience in Science and Engineering for Youth (SESEY) summer program will participate in sustainable piezoelectric research to become engaged in the nation's science and engineering enterprise.
