9 - Barium zirconate—A simple perovskite with multidimensional applications

Abstract

The chapter focuses on the synthesis, physical properties, and applications of multifunctional barium zirconate. The crystallographic arrangement of atoms inside the unit cell, defect chemistry, and thermal and chemical stability of this simple perovskite material has been introduced. A dedicated review of the synthesis techniques used for the preparation of nano and bulk barium zirconate has been presented. A detailed mechanism of oxygen vacancy formation, proton incorporation, and conduction mechanism in acceptor rare-earth-doped barium zirconate is explained. The proton conductivity of several rare-earth-substituted barium zirconate (RE-BZO) under different conditions of pH2O (g) has been tabulated. The RE-BZO compositions with the highest proton conductivity (10−2Scm−1) are used as an electrolyte in solid oxide fuel cells. The peak power density of some of the selected RE-BZO samples in SOFC configuration has been summarized. In the following part, the dielectric properties of doped barium zirconate ceramics such as the dielectric constant and temperature coefficient (τf) in the microwave regime are listed. The photophysical/optical properties of perovskite BZO have been discussed extensively, which gives signature for different colored light emissions. RE-BZO can be used in color tunable display devices. The suitable band gap of BZO favoring photocatalytic applications for H2O splitting is elaborated. The structural flexibility, chemical, mechanical, and thermal stability of barium zirconate make it a unique simple perovskite with multidimensional applications.