THERMEFLEX: THERMALLY MEDIATED FLEXOELECTRICITY

Abstract

This thesis project was successful in thermally mediated the flexoelectric effect by using a bilayer material device made up of single crystalline Strontium titanate (STO) and titanium (Ti) 10x5x0.5mm substrates connected with conductive epoxy. Heating the device with a 100 second period sine wave between -20° and 100° Celsius generated outputs from 20pA up to 100pA. Polishing allowed for device thickness variations from 1000 microns down to 400 microns. Finite Element Analysis approximations of our device deflection corresponded to within an order of magnitude to deflection measurements; however, no trend was observed concerning device thickness variation and flexoelectric output, likely due to device fabrication complications. Two separate theoretical models were developed to predict the device deflection and thus output from first principles, however both of these models failed to predict results accurately. In summary, this thesis project successfully proves the existence of thermally mediated flexoelectricity, for which the calculated efficiency was 5.8e-15. Although not likely applicable for energy harvesting at larger length scales, such an effect could be used as thermal sensor.