Title: "Dynamic Matter and Devices: Tuning Physical Functionalities via Light and Electrochemistry."

Abstract
Development of civilization requires materials. Starting from late 40ies, these developments were based on semiconductors, supporting purely electronic functionalities. Subsequently, the attention of community was captured by materials exhibiting ferromagnetic and ferroelectric functionalities. In the last 20 years, research focus worldwide shifted towards materials exhibiting coupled physical behaviors, including magnetoelectrics and multiferroics. However, the continuous emergence of new computing architectures including memristive and neuromorphic devices and development of internet of things technologies necessitate development of materials that combine chemically tunable physical functionalities, bridging classical physics and electrochemistry.

I am interested to explore and understand novel functionalities emerging in dynamic materials with mobile disorder, i.e. short- and long range ionic motion, enabling strong coupling between physical and (electro) chemical functionalities. In this talk I will discuss a class of organic-inorganic hybrid perovskites as a system model of dynamic matter. As an example, I will demonstrate that by tuning ion migration via light stimuli we were able to obtain giant current amplification in a hybrid perovskite photodetector. Next, I will focus on the interaction of environment with surface, interface and bulk in this materials system. It is revealed that coupling the redox chemistry of hybrid perovskites with the redox chemistry of gaseous (or liquid) environment via suitable electrocatalytic system may enable new classes of chemical and optical sensors and neuromorphic devices. I will then focus on exploring the nature of local phenomena at the surface and interfaces, including formation of double layers and bulk and surface ion migration and the interplay between atmosphere and ionic/electronic by probing spatially resolved phenomena using Kelvin Probe Force Microscopy (KPFM). I will also share my recent research on exploring the effect of ionic disorder on polarization and structural phenomena. Finally, I will discuss a novel functionality of these materials for potential applications as dual gamma-ray neutron sensors.

Bio
Mahshid Ahmadi is a co-principal investigator and a research assistant professor in Department of Materials Science and Engineering at UT, since 2017. Her present work includes synthesis and development of solution processable hybrid materials, electronic and ionic transport in semiconductors, probing time-resolved dynamics with nanoscale spatial information of charge transport phenomena in dynamic materials with ionic disorder and development of high radiation energy sensors. She received her BS and MS in industrial metallurgy from Shiraz University, Iran, and a PhD in Materials Science and Engineering from Nanyang Technological University, Singapore in 2013. Prior to UT, she worked as a research and technology consultant in a start-up solar cell company in Dallas, Texas, in 2014-2015. She then moved to UT as a postdoctoral researcher in 2015. Currently she has active research collaborations with CNMS, and SNS scientists in ORNL, Charles University, Prague and CBE and Nuclear Engineering at UTK. She has authored and co-authored around 30 published and submitted papers in recognized scientific journals. Her recent project was covered in the spring edition, Tennessee Engineer (2018).