Research Projects

Electrical energy consumption is rising daily because of changing lifestyles and an expanding global population. As a result, there is an increasing demand for creative ways to increase energy efficiency worldwide as well as reasonably priced, eco-friendly renewable energy sources. Particularly for portable electronics, hybrid electric vehicles, high-frequency inverters, flashlights for cameras, diesel engine starters, spacecraft, pulsed power weapons, and cardiac defibrillators, electrical energy storage is becoming a crucial enabler of sustainable renewable technologies within this framework. Research in electrical energy storage systems has focused on four energy storage systems: batteries, fuel cells, dielectric capacitors, and supercapacitors. Among them, dielectric capacitors have attracted global interest due to their high power density, fast charging-discharging ability, long-cycle life, higher working voltage, outstanding chemical stability, and low cost. Especially, dielectric thin film capacitors' tiny size, low weight, and effective storage capabilities allow them to meet the demands of sophisticated microelectronics devices and pulsed-discharge systems. Ferroics (ferroelectrics, relaxor ferroelectrics, antiferroelectrics) are the best materials to enhance the energy-storage capabilities of dielectric thin film capacitors. They can function as both DC and AC devices and exhibit increased dielectric constant and spontaneous polarization. Ferroelectrics' ability to store energy is hindered by their substantial hysteresis loss (huge Pr), thickness-dependent EBD, and critical thickness effect restricts their use in small electronic devices. Relaxor ferroelectrics are better than ferroelectrics for energy storage because of their minimal temperature dependency, low Pr, large Pmax, low coercive field, and slim P-E loops. Conversely, the antiferroelectrics are thought to be superior options for energy-storage than relaxor ferroelectrics. In this project, I will explore various lead-free ferroics (relaxor ferroelectrics and antiferroelectrics) such as Bi0.5Na0.5TiO3, NaNbO3, AgNbO3, BaTiO3 and will deposit their thin-films by RF/DC magnetron sputtering technique. To achieve better energy-storage performance, I will try to get a large Pmax, low Pr, low coercive field, slim PE hysteresis loops, high dielectric constant, low loss, low leakage current, and large breakdown strength in the thin-films by selecting appropriate compositions and dopants, tailoring microstructure, controlling the uniformity, density, crystallinity of the thin-films. I will attempt to decrease the grain size and increase band gap to to improve the electric breakdown strength of the capacitors. I will tailor the morphotropic phase boundary compositions and Curie temperature by doping to enhance energy-storage density and temperature stability. I will engineer polar nano-regions, local random field, multilayers, thickness, and orientation to obtain large Pmax.