MechE Colloquium: Electrochemically Active Metasurfaces for Multispectral Radiative Heat Management

Abstract: 

Electrochemistry is a powerful tuning knob for inducing drastic optical property changes. By applying an electrical bias while using counterions to maintain charge neutrality, electrochemistry can vary the carrier density or even trigger a phase transformation in an electrically addressable manner, which is particularly desirable in many applications where tunable range, scalability, or non-volatility is crucial. Meanwhile, metamaterials provide additional degrees of freedom to boost performance and achieve multifunctional control. However, electrochemically active metasurfaces are still largely underexplored, partly due to the lack of intrinsic property databases for newly developed materials. More co-development is needed among fundamental materials science, metasurface design, and electrochemical device engineering. In this talk, I will present two types of electrochemically active materials: (i) Conducting polymers for near-perfect dynamic thermal emitter. We conducted infrared ellipsometry to measure the potential-dependent optical property and designed a tunable metal-dielectric-metal near-perfect absorber for wearable variable emittance (WeaVE) devices for personal thermoregulation. (ii) Reversible metal electrodeposition for multispectral solar and mid-infrared control. The potential, electrolyte, and interfacial properties dictate the metal morphology, allowing reversible switching between a solar adsorber and a radiative cooler for all-year-round renewable thermoregulation for net-zero-energy buildings.


Biography: 

Po-Chun Hsu is an Assistant Professor at the Pritzker School of Molecular Engineering at the University of Chicago. He earned his PhD degree in Materials Science and Engineering and was a postdoctoral researcher in Mechanical Engineering, both at Stanford University. Prior to joining the University of Chicago, he was an Assistant Professor of Mechanical Engineering and Materials Science at Duke University from 2019 to 2022. He is a recipient of the NSF CAREER Award, shortlist for the Falling Walls Science Breakthrough of the Year 2023, Ralph E. Powe Junior Faculty Enhancement Awards, MIT Technology Review Innovators Under 35 (China), Clarivate Analytics Highly Cited Researchers, and Sony Faculty Innovation Award. His project in cooling textiles was selected as Top Ten World-Changing Ideas by Scientific American