Exploratory Chemistry of Oxide Based Compounds

Oregon State University, Corvallis OR

Investigators

Abstract

Non-technical: New materials are drivers of new phenomena and technologies. New materials discovery research and understanding of crystal structure property relationships of functional materials are critically important for the advancement of science and economic growth. With support from the Solid State and Materials Chemistry program in the Division of Materials Research, this project focuses on the discovery of new sustainable materials with crystal structures that can simultaneously exhibit multiple properties useful for designing efficient devices that can revolutionize energy, environment and electronics areas. The primary goals of the project are to discover and characterize new types of metal oxide compounds, and to understand their crystal structures, chemical bonding and physical properties. This project significantly contributes to education and research training for graduate and undergraduate students in the field of solid state and materials chemistry. This interdisciplinary project provides students with intellectual challenge of understanding complex properties of newly synthesized materials. It forges links between chemistry, physics and materials science and prepares them well for career in industrial and academic environment. High school students participating in this project gain valuable hands-on research experience and learn about the pursuit of advanced education and careers in science and technology. Technical: The primary goals of this research are discovery, synthesis and characterization of new types of metal oxides and understanding of their crystal structures, chemical bonding and physical properties. The project is based on the general theme of structure-property relationships with the aim of developing scientific concepts and experimental protocols leading to new functional materials. Focusing on the oxide class of materials, the project has the following directions: (a) Designing functional materials based on transition metal oxides with unusual structural features where metal cations occupy trigonal bipyramidal coordination. The resulting structural instability and allowed d-d electronic transitions are leveraged to create new ferroelectric materials including multiferroics and durable color pigments respectively. (b) Discovering new mixed metal oxides of tin and bismuth where Sn 5s and Bi 6s bands situated above the O 2p band leading to compounds with vivid yellow, orange and red colors for environmentally benign, durable inorganic pigments. (c) Designing superconducting oxides with square planar palladium and adjusting their carrier concentration to a region where high temperature superconductivity normally occurs in copper oxides. Various synthesis methods are used to create materials in the form of powders, sintered pellets and single-crystals. Experimental characterization tools employed include X-ray and neutron diffraction, UV/Vis/Infrared spectroscopy, scanning and transmission electron microscopy, differential thermal analysis, and measurements of electrical conductivity, dielectric and magnetic properties.