Materials Day 2025

10:55 - 11:05 AM

Extended Lattice Defects Evolution in Coupled Extreme Environments

Structural materials such as stainless steel and nickel-based alloys deployed in nuclear reactors are exposed to extreme environments comprising temperature, irradiation, stresses, and corrosive – corrosion, radiolysis and hydriding media, which poses significant challenges that demand immediate attention for the life extension of current light water reactors (LWRs) and the successful realization of next generation of nuclear reactors. This talk will discuss the use of in situ coherent X-ray diffraction imaging techniques to investigate corrosion and radiolytic processes in model nickel alloy. We will examine how corrosion-induced lattice defects evolve over time in both pristine and irradiated Ni under simulated LWR conditions. 

Ericmoore Jossou
Assistant Professor, Department of Nuclear Science and Engineering, MIT

Keynote Speaker

Material-Driven Innovation for Large-Scale Manufacturing of High-Precision Devices

In industrial applications, the term extreme materials carries a divergent meaning compared to its academic counterpart. Rather than referring to theoretical properties, extreme materials in our context are those that enable exceptionally high yield, rapid processing, and robust reliability under demanding conditions. 

These materials are not just desirable—they are essential for next-generation product performance. This talk will explore the real-world challenges driving the need for such materials across LG Innotek’s key domains: Camera modules, advanced semiconductor substrates, and more.

Mobile camera miniaturization is achieved through advanced optics and high-density packaged actuators, enabling thinner and smaller components for slimmer devices. High-performance semiconductor packaging demands the reliable integration of over one million sub-micrometer precision through vias, robust metallization, and stress mitigation to support high I/O counts on large-area substrates.

We will present our ongoing R&D efforts aimed at addressing these challenges through a materials science. Unlike academic research, our approach is grounded in industrial constraints and performance metrics, requiring solutions that bridge the gap between scientific innovation and manufacturable reality. This presentation will highlight the demands of industrial R&D and the scientific breakthroughs needed to meet them.

S. David Roh
Chief Technology Officer & Senior Vice President, LG Innotek Co. Ltd.

Computing with Protons, and How to Find Better Proton Conductors

Discovery of fast proton conductors can significantly advance a wide range of technologies, including hydrogen fuel cells, electrolyzers, electrosynthesis of fuels, batteries as well as brain-inspired computing devices. Using ions, in particular protons in inorganic materials, allows for low-energy brain inspired computing. We have demonstrated that, battery-like devices called electrochemical random access memories (ECRAM) achieve synaptic potentiation, as well as non-linear dynamics involved in local learning rules at synapses, and can serve as building blocks to enable bio-plausible and energy-efficient AI hardware. In particular this application of proton conductors need inorganic, fast proton conductors at room temperature to improve speed, energy and programming voltage needed.
A quantitative understanding of the physical traits of a material that regulate proton conduction is necessary for accelerating the discovery of fast proton conductors. While electronic and structural descriptors have been found to facilitate proton conductivity, the role of lattice dynamics remain unexplored quantitatively, albeit hypothesized to be important in affecting proton conduction. 
In this work, we have mapped the structural, chemical and dynamic properties of solid acids and ternary oxides to the elementary steps of the Grotthuss mechanism of proton diffusion. Our approach combines ab initio molecular dynamics simulations, analysis of phonon spectra and atomic structure calculations. The found physical descriptors of proton conduction also provide paths for increasing the conductivity at low temperature. With the rapid growth of material databases, our approach lays ground for physically informed search of fast proton conductors and enlarges the chemical space of materials to power the green revolution.

Bilge Yildiz
Professor, Department of Nuclear Science and Engineering, MIT

From Giant Optical Changes to Extreme Endurance: Phase Change Materials for Photonics

Phase change materials (PCMs) exemplify extreme materials by combining exceptionally large, reversible optical property changes with the capacity to withstand harsh thermomechanical cycling during repeated switching. Our recent work shows that by identifying and mitigating failure mechanisms under such extreme conditions, photonic devices can achieve tens of millions of reliable cycles, a breakthrough compared to the thousand-cycle limit of earlier demonstrations. This resilience under intense thermal and mechanical stress paves the way for robust photonic technologies including reconfigurable circuits, programmable metasurfaces, neuromorphic photonics, and adaptive infrared systems. By linking fundamental materials insights with device-scale engineering, PCMs are emerging as a new class of extreme materials capable of sustaining demanding applications while delivering transformative optical performance.

Juejun Hu
Professor, Department of Materials Science and Engineering, MIT

Polymer Materials for Bioelectronics

In this talk, I will share recent progress from my research group, the Laboratory of Organic Materials for Smart Electronics (OMSE Lab), on designing polymer-based electronic components for bioelectronic devices. These devices are central to the next generation of "smart" electronics for healthcare and consumer applications. Our research focuses on addressing the unique demands of such systems, which require a combination of mechanical flexibility, environmental stability, reliable signal processing, and functional adaptability. In particular, I will highlight our recent efforts to engineer mechanically deformable electrodes through an exponential stacking strategy. This method overcomes a major limitation of traditional stretchable electronics, which often require a tradeoff between mechanical compliance and electronic performance. With exponential stacking, increasing the number of layers simultaneously enhances both electrical conductivity and strain tolerance without compromising device functionality. This scalable approach has enabled the development of soft electronics capable of recording electrophysiological signals in vivo from the small intestines—a first for this application. Additionally, these materials support electrical stimulation, making them suitable for both biosensing and neuromodulation. Notably, this method is compatible with a wide variety of metals, including highly reactive ones like, which are typically not stretchable when deposited on elastomeric substrates. As a result, we are developing a versatile platform for bioelectronics with the potential to address key challenges in biosensing and biomedical device engineering. I will also share our work on using polymer composites in synaptic transistors. These composites enable a balance between ionic permeability and efficient electronic charge transport, which is essential for creating high-performance materials needed in stimulus-responsive and adaptive electronics, particularly for bioelectronic applications.

Aristide Gumyusenge
Assistant Professor, Department of Materials Science and Engineering, MIT

Capturing Light Induced Phase Transitions with Femtosecond Movies

Materials typically undergo phase changes as a function of external parameters such as temperature, pressure or magnetic field. Light can also be used to both switch between equilibrium phases and to create new photo-induced states that may have no equilibrium counterparts. Even though there are fascinating examples of photoinduced phase transitions, the detailed microscopic mechanisms and overarching principles that govern these are still not known. In this talk, I will present two recent examples of this phenomena. First, I will describe how we used ultrashort laser pulses to capture light induced melting and recovery of a charge density wave phase with femtosecond time resolution. During this process, a new state that does not exist in equilibrium is also transiently created. Secondly, I will show experiments in which high field THz pulses are used to induce metastable magnetization in a layered antiferromagnet. Understanding light induced phase transitions could pave the way for optical engineering of new quantum states of matter.

Nuh Gedik
Professor, Department of Physics, MIT