Since it is my first time in Boston, bunch of my friends and previous colleagues are very excited to show me their favorite cafes and food places around the town. One of my good friends who works for Boston Dynamics across the bridge invited me to his workplace, and I got to see and drive the famous Quadruped robot! I truly have to admit, engineering rocks!
MRS TV heads back to Symposium X to see Giulia Grancini's lecture about hybrid perovskite solar cells and their role in creating a sustainable future.
Rachel Egan, University of Cambridge, United Kingdom
Polymer-modified 3D Electrode Interfaces for Efficient Charge Extraction from Photosynthetic Microorganisms
Written by Birgul Akolpoglu
Rachel Egan of the University of Cambridge addresses the challenge of low current generation in photosynthetic microorganisms, specifically cyanobacteria, for three-dimensional (3D) electrodes. Egan proposed a solution using 3D electrode scaffolds, focusing on hierarchically structured inverse opal indium tin oxide electrodes to increase surface area. Employing conductive and redox-active polymers like PEDOT (conductive, biocompatible) and osmium-based redox polymer, she optimized interfacial chemistry for efficient charge extraction. PEDOT-coated electrodes demonstrated a 20-fold increase in photocurrent output compared to non-coated ones, though light penetration posed a limitation. Transitioning to an osmium-based redox polymer, fully encapsulating cells, resulted in a 70-fold increase in photocurrents. Egan explored the significance of osmium density in the polymer, achieving a 70-fold increase of photocurrents with an iterated version that has higher osmium density. Electrostatic interactions between the extracellular polymeric substances on algal surfaces and polymer played a crucial role in facilitating effective wiring. Egan emphasized a comparison between osmium redox polymer and PEDOT, considering factors such as light management, onset potential, and scalability as essential aspects in advancing sustainable electrode technologies using photosynthetic microorganisms.
Nicholas Glavin, Air Force Research Laboratory, USA
Laser Induced Oxidation and Defect Formation in 2D Materials
Written by Ankita Mathur
Nicholas Glavin of the US Air Force Research Laboratory developed different phases of molybdenum oxides on a single crystal thin film using laser induction on α- MoS2. To make the presentation more interesting, he started with the results, and later proceeded toward the motivation and introduction. The laser of different powers were induced on the thin film of α- MoS2 for varying times, which resulted in development of a colorful phase diagram representing various oxides and sulfides form of molybdenum, along with multiple defects and vacancies. It gives rise to multifunctional properties and a wide range of applications, including pathogen detection and in sensors. Glavin also demonstrated that the same procedure can be adopted for developing different phases in TiS2. In addition, roll-to-roll manufacturing of these thin films is also possible.
Matteo Seita, University of Cambridge
From Complex Geometries to Complex Microstructures: New Opportunities for Materials Design
Written by Corrisa Heyes
Matteo Seita, head of the Additive Microstructure Engineering (AME) Laboratory at the University of Cambridge, showcases a process for the manipulation of material properties of structures constructed via additive manufacturing (AM), specifically in laser powder bed fusion. Similar to the way metalsmiths have been affecting the texture, phases, and strain in their macroscale products for thousands of years, the AME Lab is experimenting with microscale “surrogate” thermomechanical processing for AM structures. Furthermore, due to the nature of the layer-by-layer AM process, the materials properties of each layer can be variably tuned. As an example, Seita presents their work to develop site-specific recrystallization control in stainless steel 316L. This is achieved through the variation of scanning speed and hatch spacing during the manufacturing process and are demonstrated to lead to the possible application of bulk AM “heterostructured” materials with enhanced materials properties.
Michael J. Aziz, Harvard John A. Paulson School of Engineering and Applied Sciences, USA
Electrochemically-Driven Solution-Phase CO2 Capture
Written by Ankita Mathur
CO2 capture is one of the ways to reduce global warming and reduce the amount of CO2 emission in the environment, and Michael J. Aziz of Harvard University focuses on one of the methods for achieving this goal. He demonstrated the wide scale applications of quinone materials in capturing CO2. Quinone molecules absorb CO2 and converts it into different carbonate forms. But the presence of O2 kills the columbic efficiency of the reaction by reducing the electrolyte. Aziz also talked about an organic molecule called 1,8 ESP which can be used for CO2 capture as well as for energy storage and is resistant to atmospheric O2. These molecules absorb CO2 and store energy during charging, and release CO2 and delivers energy upon discharging. These molecules capture CO2 based on pH swing cycles driven through proton-coupled electron transfer mechanisms.
Renkun Chen, University of California, San Diego, La Jolla
High-Temperature Thermal Energy Transport and Conversion using Photonic Nanostructures and Metamaterials
Written by Corrisa Heyes
Renkun Chen of the Mechanical and Aerospace Engineering Department at the University of California, San Diego highlighted the crucial role of high-temperature thermal energy transport and management in various energy processes. These areas included thermochemical, solar-thermal, thermophotovoltaic, thermal energy storage, and industrial heating. Chen described how the physics of heat transfer at elevated temperatures differs significantly from that at room temperature, involving stronger phonon-phonon scattering and a more dominant role of radiation heat transfer. Chen emphasized the challenges posed by high temperatures on materials, particularly thermal and chemical stability. He presented two recent studies: one explores the influence of surface phonon polaritons in polar dielectric nanostructures on thermal radiation and conduction, demonstrating the manipulation of nanostructure geometry for engineered heat conduction. The second focuses on developing high-temperature, stable, selective emitters based on metamaterials, offering efficient conversion of optical and electrical energy into thermal energy for thermophotovoltaic and infrared heating applications.
Kevin Kit Parker, Harvard University, USA
Arts & Crafts or Engineering? Tissue Engineered Hearts
Written by Birgul Akolpoglu
Kevin Kit Parker says the heart is his favorite organ. He defines the heart as a biochemically powered, electrically activated, pressure and volume regulated, two-state, tandem mechanical pump. Building a heart from scratch is a hierarchical problem, he says, as he then poses the question to the audience: are we supposed to be building form or function as we are building a heart?
Focusing on nanoscale extracellular matrix (ECM) networks, Parker’s research team uses methods such as pull spinning and rotary jet spinning to create centimeter-scale networks with nanoscale features. Drawing inspiration from marine life, particularly fast and responsive muscles in marine creatures including jellyfish, Parker explores bio-synthetic models. He highlighted the creation of a medusoid, mimicking the swimming strokes of wild-type jellyfish. Notably, the team constructed a biohybrid stingray with curved tissues, showcasing untethered navigation. Incorporating human-induced pluripotent stem cell-derived cardiac muscle cells and optogenetics, the research team engineered a self-swimming fish. Parker’s innovative approach combines biology and engineering for advancements in tissue engineering and artificial muscular pumps.
Moungi Bawendi, Massachusetts Institute of Technology
Indistinguishable Single Photons from Colloidal Quantum Dots
Written by Birgul Akolpoglu
Moungi Bawendi, recipient of the 2023 Nobel Prize in Chemistry for his groundbreaking work on quantum dots, shared insights into his latest research on indistinguishable single photons. Having received the prestigious prize only last month, he was very humbled, and he attributed the prize to his scientific community and dedicated research group, emphasizing their three decades of hard work in the field of quantum dots. Bawendi marveled at the ever-expanding applications of quantum dot technology, from light-emitting diode displays to lasers and solar cells.
Acknowledging the diverse background of his audience, Bawendi transitioned to foundational concepts, illustrating the famous double-slit electron experiment. This experiment highlights the dual nature of particles, exhibiting both wave-like and particle-like behavior. He then moved on to discuss the Hong-Ou-Mandel (HOM) effect in quantum optics, elucidating how indistinguishable photons become entangled at a beam splitter, consistently emerging together in one of the output ports.
Concluding his talk, Bawendi outlined future directions and open questions in colloidal quantum dots research. These include exploring exciton dephasing, optimizing synthetic design for enhanced performance, and advancing the fundamental understanding of structure-function relationships. His group at the Massachusetts Institute of Technology is actively engaged in a broad spectrum of topics, from nanomaterials synthesis, and spectroscopy to various applications in bioimaging and solar energy harvesting.
The 2023 MRS Von Hippel Award, the society’s highest honor, is awarded to Reshef Tenne, Weizmann Institute of Science, for spearheading modern research on nano-2D materials through the discovery of nanotube- and fullerene-like inorganic layered compounds.
MRS TV talks to Dr. Tenne about his discoveries in nanoparticles.