Materials Research Lecture

My talk will consist of two parts. The first one will focus on heat-to-electricity and solar-to-electricity energy converters that are based on evaporation of electrons from solid surfaces (thermionic effect).

Microfabrication is the optimal manufacturing approach for thermionic energy converters because the optimal cathode-anode gap for TECs is in the range of 1-10 μm, which is highly suitable for MEMS-based fabrication processes. Our structures were optimized to sustain extremely high temperatures (above 2000 K) even when operating just a few microns from the room-temperature substrate.

The second part of the talk will focus on novel ultra-lightweight plate materials recently developed in my group. Using a periodic three-dimensional patterning, we have fabricated free-standing plates up to 2 cm in size out of aluminum oxide (alumina) films as thin as 25 nm. They weigh as little as 0.1 gram per square meter, and have the ability to "pop-back" to their original shape, without damage, even after undergoing multiple sharp bends by more than 90 degrees. I will briefly discuss the mechanical properties and possible applications of these plate mechanical metamaterials.

More about the speaker: Igor Bargatin received the B.S. degree in theoretical physics from the  Lomonosov Moscow State University, and the Ph.D. degree in physics and electrical engineering from the California Institute of Technology, Pasadena. After postdoctoral appointments at LETI/Minatec (Grenoble, France) and Stanford University, he became the Class of 1965 Term Assistant Professor in the Department of Mechanical Engineering and Applied Mechanics (MEAM), University of Pennsylvania. Prof. Bargatin's research interests are focused on micro- and nanoelectromechanical systems (MEMS/NEMS) for new applications in energy conversion and ultra-lightweight materials.