HomeEducationGraduate and Undergraduate ProgramsResearch Experience for Undergraduates (REU)REU 2017 ProjectsControlling Electronic Conductivity in Oxides by Manipulating Cation Site Disorder

Controlling Electronic Conductivity in Oxides by Manipulating Cation Site Disorder

Professor: Richard Robinson

Project Description

If we were able to control the electrical conductivity of oxides we could dramatically change how these materials are used in catalysis, batteries, and supercapacitors. What is known is that small tweaks to the cation site positions can greatly affect conductivity in oxides, but manipulating cation positions is a challenge in bulk materials due to kinetic limitations. In nanoparticles, however, we believe we can beat these limitations due to the accelerated kinetics provided by nanoparticle chemical transformation reactions. In this project, the student will test this hypothesis by creating nanoparticle oxides and manipulating the cation ordering.

The target system for this study is oxide spinels. Most spinel oxides conduct charge carriers through a mechanism called small polaron hopping. During this, the charges and lattice vibrations are coupled, and jump between octahedral cations.

In this project the student will study the effects of configurational disorder on polaron electronic transport in spinels by creating and characterizing nanoparticle films of spinels. The student will learn nanoparticle synthesis methods and characterize the particles to ensure purity, phase, and size dispersion – learning x-ray diffraction (XRD) and associated nano-characterization methods. The nanoparticles will be then built into a conducting thin film and measured as a device. The student will pursue Electrochemical Impedance Spectroscopy (EIS) as a further means to evaluate the electronic transport.

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