Enzymatic Bioelectrocatalysis for Electrosynthesis.

Dr. Shelley Minteer, Dale and Susan Poulter Endowed Chair in Biological Chemistry, Department of Chemistry, University of Utah

Held at 3pm in G-3 Schrenk Hall 

Abstract: In the last 5 years, there have been extensive studies and new materials designed for interfacing biocatalysts with electrode surfaces for applications in energy storage and electrification of industry. This talk will discuss electroanalytical techniques for studying biocatalysis, including both mediated enzymatic bioelectrocatalysis and direct enzymatic bioelectrocatalysis. The talk will discuss electrode materials innovation for interfacing complex proteins with electrode surfaces as well as using them for electrosynthesis of ammonia as well as other value-added products (i.e. chiral amines, chiral imines, polymers, etc.) with a focus on sustainability in the chemical industry.  Finally, this talk will discuss the use of synthetic biology for microbial bioelectrosynthesis of ammonia and other value-added products, as an alternative to enzymatic bioelectrocatalysis.

Click to view the flyer for Dr. Shelley Minteer Seminar flyer (PDF)

Mechanochemistry: From Scientific Mystery to Scalable Materials Preparation and Recycling Technique.

Dr. Viktor P. Balema, CTO, ProChem Inc., Rockford, Illinois & Adjunct Professor, Clemson University, Clemson, South Carolina

Held at 3:15 pm in 303 Schrenk Hall

Abstract: The presentation addresses the Mechanochemical approach to the solid-state synthesis technique that enables solvent-free preparation of a great variety of molecular, ionic and hybrid inorganic – organic materials.  State of the art in the field of Mechanochemistry is briefly reviewed using authors and other researchers’ experimental results as examples, and possible mechanisms of mechanochemical transformations are highlighted.  Mechanochemical preparations of novel hybrid and complex materials such as 3D transition metal dichalcogenide heterostructures, high-entropy transition metal dichalcogenides (TMDCs) and rare earth-based metal organic frameworks (MOFs) are discussed, and the recently discovered mechanochemical depolymerization of an addition polymer, polystyrene, to monomeric styrene at room temperature under ambient atmosphere is presented. Transformation of research materials into commercial products and scaling up laboratory protocols will be highlighted using mechanochemical processes as examples.

Click to view the flyer for Dr. Viktor Balema’s seminar flyer

Introduction to Photolithography

Joyce Lowes, Director of Emerging Materials, Brewer Science’s Corporate R&D

Held at 3:15 pm in 303 Schrenk Hall

Abstract: Nearly all the electronic devices that make the world what we know today, from supercomputers, self-driving automobiles, and smart phones to children’s toys and musical greeting cards, rely on integrated circuits (ICs). IC manufacturing is based on a process called photolithography. Photolithography is used in combination with other techniques to build the billions of nanoscale transistors used in each one of today’s integrated circuits. In this session, we’ll review a quick history of ICs and introduce the processes used to make these devices, focusing on photolithography and how a small company in Missouri helps lead development of some of the most advanced devices in the world.

Joyce Lowes's seminar flyer

Extending Moore’s Law Through Advanced Packaging

Dr. Andrea Chacko, Program Manager of Packaging Solutions, Brewer Science’s Corporate R&D

Held at 3:15 pm in 303 Schrenk Hall

Abstract: For the past several decades, the semiconductor industry has been guided by Moore’s law toward continual miniaturization of devices. Advances in photolithography and the shrinking of transistors have traditionally been the primary means of achieving improved performance. Now however, in addition to continued improvements in lithography, the development of advanced packaging is widely considered an essential key to enabling still smaller and faster devices with added functionality and reduced cost of ownership. Many approaches for the packaging of semiconductors have been utilized, but all advanced packaging technologies rely on advanced materials to address the many challenges in achieving continued shrinking and improved performance of devices. This presentation will be an introduction to semiconductor packaging and highlight the advanced materials needed to address the growing challenges in the industry.

Andrea Chacko's seminar flyer

New Material Needs in the Semiconductor Industry

Dr. Reuben Chacko, Scientist/Team Lead in ELECTRO program, Brewer Science’s Corporate R&D

Held at 3:15 in 303 Schrenk Hall

Abstract: Big data is driving huge transformations across every industry. It’s talked about as the new currency of the economy. More advanced technologies, including smaller-feature devices and new technology approaches, are needed to meet the growing demands of big data. New materials with advanced performance are needed to enable these technologies. This presentation will provide an introduction into new material needs driven by technology trends in the semiconductor industry.

Reuben Chacko's seminar flyer

Materials Discovery through Machine Learning: Experimental Validation and Interpretable Models

Dr. Arthur Mar, Department of Chemistry, University of Alberta, Edmonton, AB, Canada

For more information, click here. 

Abstract: Machine learning algorithms have been applied successfully in many areas of materials chemistry. An ongoing challenge is to make accurate predictions of the crystal structures of inorganic solids, their site preferences, and their physical properties. We have previously developed machine learning models to predict structures within the large family of intermetallic compounds known as Heusler compounds (used as thermoelectric materials, ferromagnets, magnetocaloric materials, and catalysts), followed by experimental validation. Nevertheless, skeptics rightfully criticize many of these models as being too “black box,” with little chemical insight and explainability. We demonstrate our efforts to generate more interpretable machine learning models, using the structures of binary rare-earth intermetallics RX as an example, to illustrate that it is possible to gain insight and practical guidance to prepare new materials.

Click to view Dr. Mar's Colloquium Flyer.

From Stealth to Climate Change – the Pursuit of Propulsion-derived Particulate Matter Characterization at Missouri S&T.

Dr. Phillip D. Whitefield, Dept. of Chem., Missouri S&T. 

Held at 2:00 p.m. in Schrenk G3. 

Abstract: Propulsion-derived particulate matter (PM) characterization has been a major research area in physical/analytical chemistry at Missouri S&T since 1988. In this retrospective lecture the nature of this combustion by product and criteria pollutant, will be discussed, along with the research and regulatory methods developed to monitor and characterize it. By way of example, research related to engine type and operating conditions for both airborne and space flight will be presented as will the influence of fuel formulation. The desire to understand the influence on PM emissions arising from alternative, renewable aviation fuels relies heavily on the huge database that exists for conventional fuels much of which has resulted from the application of the methods and data interpretation developed at MS&T examples will be discussed.

Click to view the flyer for the 7th Annual Stoffer Lecture

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State of the S&T Department of Chemistry: Focus on the Graduate Program

Dr. Rainer Glaser, FACS, FRSC, FAAAS, Chair, Dept. of Chem., Missouri S&T

Abstract: The S&T Department of Chemistry is a dynamic organization with complex interactions between material infrastructure and staff support, a diverse population of undergraduate, graduate, and post-doctoral students, and an international faculty. Modern science is a global enterprise adding an exciting and mutually enriching cross-cultural component to the complexity. The department’s success depends on synergy across all of its components and active faculty participation with shared ethics, goals, and aspirations. The on-going global pandemic has been challenging and consequential with direct consequences on the practices of teaching and research and leading to a stronger focus on service and prosocial designs. Our scientific creed requires curiosity, energy, initiative, and excellence in interdisciplinary science and the development of skills, knowledge and abilities to optimize teamwork, responsible conduct of research, and the interrelations between the teaching, research and service missions. In this presentation, we will address strengths and challenges with regard to departmental infrastructure, chemistry instrumentation, faculty and scientific staff, digital communication, outreach activities, and the evolution of the undergraduate and graduate programs. Special focus will be placed on aspects of the Graduate Program and the roles of graduate students.

Due to inclement weather, the February 4th Colloquium has been rescheduled for February 18th.

Glucose regulation from corals to humans

Dr. Judith Klein-Seetharaman, School of Molecular Sciences, College of Health Solutions, Arizona State University, Phoenix, AZ

For more information, click here. 

Abstract: Once thought to be a unique capability of the Langerhans Islands in the pancreas of mammals, insulin production is now recognized as an evolutionarily ancient function going back to prokaryotes, ubiquitously present in unicellular eukaryotes, fungi, worm, Drosophila and of course human. While the functionality of the signaling pathway has been experimentally demonstrated in some of these organisms, it has not yet been exploited for pharmacological applications. To enable such applications, we need to understand the extent to which the structure and function of the insulin-insulin receptor system is conserved. To this end, we analyzed the insulin signaling pathway in corals through remote homology detection and modeling. By docking known insulin receptor ligands to a coral homology structure, we locate ligand binding pockets and demonstrate their conservation suggesting that it may be possible to exploit the structural conservation for pharmacological applications in non-model organisms. We also identified the coral homologues of the over 100 signaling proteins involved in insulin and its related signaling pathways, demonstrating their wide-spread conservation. Notable exceptions are glucagon and somatostatin. It is tempting to speculate that under high light conditions, when the algae synthetize excess sugars, the cnidarian host may experience insulin resistance, and that the cnidarian microbiome may be involved in manipulating the insulin signaling system. Implications of the findings for new areas for monitoring and regulating glucose concentrations will be discussed.

Neurobiology and Neuroimaging of COVID-19

Dr. Cyrus Raji, MD, PhD, School of Medicine, Washington University, St. Louis, MO. 

For more information, click here. 

Abstract: Anosmia, stroke, paralysis, cranial nerve deficits, encephalopathy, delirium, meningitis, and seizures are some of the neurological complications in patients with coronavirus disease-19 (COVID-19) which is caused by acute respiratory syndrome coronavirus 2 (SARS-Cov2). There remains a challenge to determine the extent to which neurological abnormalities in COVID-19 are caused by SARS-Cov2 itself, the exaggerated cytokine response it triggers, and/or the resulting hypercoagulapathy and formation of blood clots in blood vessels throughout the body and the brain. In this article, we review the reports that address neurological manifestations in patients with COVID-19 who may present with acute neurological symptoms (e.g., stroke), even without typical respiratory symptoms such as fever, cough, or shortness of breath. Next, we discuss the different neurobiological processes and mechanisms that may underlie the link between SARS-Cov2 and COVID-19 in the brain, cranial nerves, peripheral nerves, and muscles. Finally, we propose a basic “NeuroCovid” classification scheme that integrates these concepts and highlights some of the short-term challenges for the practice of neurology today and the long-term sequelae of COVID-19 such as depression, OCD, insomnia, cognitive decline, accelerated aging, Parkinson’s disease, or Alzheimer’s disease in the future. In doing so, we intend to provide a basis from which to build on future hypotheses and investigations regarding SARS-Cov2 and the nervous system.

TBD

Defining ChemEd Research and its Challenges

Dr. Diana Mason, Professor Emeritus, Department of Chemistry, University of North Texas, Denton, TX

Abstract: It can be argued that designing any study is as much of an art as it is a science, and this is certainly true when dealing with Chemistry Education Research (CER) protocols. Given our departmental status, CER is frequently compared to bench research and challenged by many who might see CER as questionable but is it truly that much different? The answer is Yes and No. The most unique challenge faced by CERers (and rarely faced by bench researchers) is the fact that people are almost always part of the protocol, and consequently several layers of approvals (IRB, consents and assents) are needed before the first question can be asked. The next challenges are that the starting and stopping points of an experiment are usually constrained by when students are available and acquiring a “mole” of students can be difficult when the DFW rate exceeds 40%! After the data are collected, then the real challenges begin—are the results repeatable, can they be generalized, do they add to or support the intended theoretical base, what are the limitations, and does the original question lend itself to further investigations? The similarities between the different types of research should now be more obvious: are not the last questions the same as those for any other research project? In this presentation, addressed will be the evolution of a data-driven CER career on the teaching and learning of chemistry, and how successful projects have led to a greater understanding of how students learn to learn chemistry.

For more information, click here. 

Science Ethics, Goals and Aspirations in Times of Change

Dr. Rainer Glaser, FACS, FRSC, FAAAS, Chair, Dept. of Chem., Missouri S&T

Abstract: The S&T Department of Chemistry is a dynamic organization with complex interactions between material infrastructure and staff support, a diverse population of undergraduate, graduate and post-doctoral students, and an international faculty. Modern science is a global enterprise adding an exciting and mutually enriching cross-cultural component to the complexity. The department’s success depends on synergy across all of its components and active faculty participation with shared ethics, goals, and aspirations. The on-going global pandemic has been challenging and consequential with direct consequences on the practices of teaching and research and leading to a stronger focus on service and prosocial designs. Our scientific creed requires curiosity, energy, initiative, and excellence in interdisciplinary science and the development of skills, knowledge and abilities to optimize teamwork, responsible conduct of research, and the interrelations between the teaching, research and service missions. In this presentation, we will address strengths and challenges with regard to departmental infrastructure and personnel, chemistry instrumentation, faculty and scientific staff, and the evolution of the undergraduate and graduate programs. Practical proposals will be presented to achieve both gradual and bold evolution towards our shared goals.

For more information, visit the webpage here. 

Alkaline and bipolar membrane electrolyzers: A route to scalable energy storage and conversion?

Dr. Shannon Boettcher, Professor, Dept. of Chem. and Biochem., University of Oregon, Eugene, OR, 97403

Abstract: Commercialized membrane electrolyzers use acidic proton exchange membranes (PEMs). These systems offer high performance but require the use of expensive precious-metal catalysts such as IrO₂ and Pt that are nominally stable under the locally acidic conditions of the ionomer. I will present our efforts to study and develop alternative electrolysis platforms.

First, I will discuss alkaline-exchange-membrane (AEM) electrolyzers that, in principle, offer the performance of commercialized proton-exchange-membrane electrolyzers with the ability to use earth-abundant catalysts and inexpensive bipolar plate materials. I will present our fundamental work in understanding earth-abundant water-oxidation catalysts as well as progress in building high-performance AEM electrolyzers. To date, our best systems operate at 1 A·cm^-2 in pure water feed at < 1.9 V at a moderate temperature of 69 °C. These devices, however, degrade rapidly (~ 1 mV/h) compared to PEM electrolyzers. I will show how we assess chemical changes to the anode and cathode catalyst and ionomer that is correlated with this performance loss, as well as present strategies to mitigate degradation.

Second, I will introduce the use of bipolar membranes (BPMs) in electrolysis devices. BPMs consist of an AEM and PEM laminated together. Under the appropriate bias, they conduct ionic current by dissociating water into protons and hydroxide at the AEM/CEM junction. Commercially, BPMs are used in electrodialysis, but generally are limited to low current densities below 100 mA cm^-2 to avoid large losses in driving water dissociation. I will present our fundamental studies on how to accelerate water dissociation in BPMs (Science, 2020) and how that has enabled BPMs operating at > 3 A cm^-2 and with improved efficiency. BPMs limit crossover and enable operation of a cathode and anode in different pH conditions and are thus seeing substantial interest for CO₂ electrolysis, advanced electrodialysis systems, and water electrolysis.

For more information, visit the webpage here. 

Hyperpolarizing nuclear spins of atoms and molecules with light and parahydrogen

Dr. Boyd Goodson, Professor, Distinguished Scholar & Acting Associate Dean, Dept. of Agricultural, Life and Physical Sciences, SIUC, Carbondale, IL 62901

Abstract: NMR and MRI enjoy wide applicability but often suffer from poor detection sensitivity owing to low nuclear spin polarization. For example, MRI can provide exquisite anatomical images of soft tissues in the body – without ionizing radiation – but the MRI signal comes almost entirely from high-concentration 1H nuclei in the body’s water and fat molecules. It would be extremely informative to instead obtain MRI signals from various low-concentration species (e.g. metabolites in cancer or gases in lung space), but the resulting signals are normally just too weak to provide useful images. To combat this problem, we are pursuing two methods for generating high, non-equilibrium nuclear spin polarization – a.k.a. “hyperpolarization”: (1) spin-exchange optical pumping (SEOP); and (2) parahydrogen induced polarization (PHIP).  In SEOP, resonant circularly polarized light from a high-power laser is used to polarize the electron spins of an alkali vapor (usually Rb or Cs); the nuclear spins of a noble gas (e.g. xenon) may then become hyperpolarized over time as a result of spin exchange during gas-phase collisions.  We are particularly interested in both the study of fundamental phenomena underlying SEOP and the development of SEOP technology -- efforts that have led to new approaches for generating "clinical-scale" quantities of hyperpolarized xenon-129 for biomedical applications (including human lung imaging). Recently, we have also been working to hyperpolarize xenon-131 (a quadrupolar isotope that is far more difficult to polarize), with potential application in targets for polarized neutron scatting experiments in the search for new physics beyond the Standard Model.  In PHIP, the singlet state of parahydrogen--a spin isomer or ordinary molecular hydrogen gas--is utilized as the source of spin order to create hyperpolarization.  PHIP-based hyperpolarization approaches are attractive because they are rapid, ultra-cheap, easy, scalable, and have a low instrumentation / infrastructure burden.  In "traditional" PHIP, hyperpolarization is achieved by a permanent chemical reaction -- pairwise hydrogenative addition across asymmetric unsaturated (double or triple) chemical bonds.  However, in the newer approach called SABRE (signal amplification by reversible exchange), no permanent chemical change is required; instead, SABRE utilizes an organometallic catalyst that transiently binds both parahydrogen and the target substrate molecule, thereby allowing the target spins to be hyperpolarized through the scalar coupling network.  In collaboration with others, we are studying SABRE with heterogeneous catalysts, in aqueous environments, and in variable magnetic fields in order to create hyperpolarized agents for in vivo NMR and MRI. We are particularly interested in approaches that allow efficient separation of hyperpolarized molecules from PHIP/SABRE catalysts, and/or allow longer-lasting hyperpolarization – particularly in various heteronuclei (15N, 13C, etc.).

For more information, visit the webpage here. 

Electrodeposition of Transparent and Flexible Electronics

Dr. Jay Switzer, Chancellor’s Professor, Curators’ Distinguished Professor Emeritus, and former Donald L. Castleman FCR Missouri Endowed Professor of Discovery in Chemistry, Dept. of Chemistry, Missouri S&T

Abstract: Single-crystal silicon is the bedrock of semiconductor devices due to the high crystalline perfection that minimizes electron-hole recombination, and the dense SiO_x native oxide that minimizes surface states. One issue with the material is that it is both brittle and opaque. There is interest in moving beyond the planar structure of conventional Si-based chips to produce flexible and transparent electronic devices such as wearable solar cells, sensors, and flexible displays. In this talk we will discuss the electrodeposition of transparent, wide bandgap semiconductors such as ZnO, CuI, and CuSCN that can be produced as epitaxial films on single-crystal substrates. These epitaxial films have an orientation that is controlled by the substrate, with electronic properties that mimic those of single crystals. We also show that the epitaxial films can be removed by a simple lift-off procedure to produce single-crystal-like flexible foils of transparent semiconductors.

See the informational bifold here and the itinerary here. For more information, visit the webpage here.

Development and Fundamental Understanding of the World’s Most Versatile Polymers, Polybenzoxazine: From Smart to Extreme Properties

Dr. Hatsuo Ishida, Peter A. Asseff, PhD Professor of Organic Chemistry, Department of Macromolecular Science and Engineering,  Case Western Reserve University, Cleveland, Ohio 44106-7202

Abstract: We are now in the dark age of commercialization of new polymers. In the past 40 years, only a few new polymers have been commercialized. The subject of the lecture, polybenzoxazine, is one of them. It is an extremely versatile material that can be readily synthetized from off-the-shelf commercially available raw materials, and the material can be easily tailored to the desired properties. They can also be synthesized from many natural renewable raw materials, such as cashew nut shell oil, vanillin, chitosan, and furfural amine. Polybenzoxazines exhibit several unusual properties other polymers do not show, including surface free energy lower than Teflon without fluorine atoms, extremely high char yield, near-zero shrinkage upon polymerization, and property increase at low conversions. Polybenzoxazines defy the common wisdom of “the higher the properties, the more expensive and difficult to process,” It can be easily processed like an epoxy resin, and show an unusual “polymerization temperature << Tg” relationship. Utilizing these advantageous and very versatile properties, we have been developing a number of materials that can be applied to many potential fields, such as aerospace, electronic, automotive, coating, catalysis and many others. The lecture introduces fundamental unique chemistry of benzoxazine polymerization, and development of smart, high-performance and extreme performance materials.

For more information, visit the website here. 

Unraveling molecular interconnections between circadian rhythms and lipid metabolism

Dr. Xuemin (Sam) Wang, E. Desmond Lee and Family Fund Endowed Professor, Dept. of Biology, UMSL, St. Louis, MO

Abstract: Misalignments and disruption of the circadian clock lead to metabolic and physiological dysfunctions. The clock regulates metabolism whereas metabolic activities feedback to influence circadian rhythms. This interplay between the clock and metabolism is expected to strengthen both processes and coordinate physiology. However, one major knowledge gap is the limited understanding of the mechanism by which metabolism affects clock function. One of our ongoing projects is to investigate interconnections between the circadian clock and lipid metabolism using the model organism Arabidopsis. The study has identified specific molecular interactions between the clock and lipid mediators. Manipulation of those interactors perturbs lipid accumulation and circadian rhythms. The results suggest that the molecular interaction may function as a cellular conduit to help integrate the circadian clock, lipid metabolism, and organismal response to environmental changes. Further elucidation of the interplay will unveil new regulatory mechanisms for the circadian clock and lipid metabolism. The information has the potential for future strategies to understand and mitigate metabolic and physiological disorders associated with clock disruptions.

For more information, visit the webpage here. 

Vibrational State Specific Rates of HCCCN Formation in Dissociation of CH₂CCN

Dr. Kirill Prozument, Chemist, Experimental Physical Chemistry, Argonne National Laboratory, Lemont, IL 60439

Abstract: Predictive models describing complex reaction networks in the gas phase require the knowledge of thousands of elementary reaction processes occurring over a range of conditions. These elementary processes are coupled together in ways that lead to significant deviations from standard thermal assumptions. For example, in the phenomenon of “prompt” non-thermal reactions the products passing through the transition state often proceed down the hill on the potential energy surface and are formed with considerable amount of translational, vibrational, and rotational energy. That energy may be sufficient to further dissociate the product molecule to smaller fragments. Alternatively, the molecule may be stabilized or react. Vibrational state-resolved kinetic measurements of the products provide an intriguing window into understanding and quantifying these non-thermal effects. In this work we observe the reaction product HCCCN arising from the two stage photo-induced dissociation of vinyl cyanide in various vibrational states (ground state, ν₇ and ν₆ bending modes) and measure the HCCCN formation rates in each of those states. These measurements are performed with the Time-Resolved Kinetic Chirped-Pulse experiment. The precursor CH₂CHCN molecules in the flow reactor are dissociated with a 193 nm laser and probed by a 260–290 GHz chirped-pulse rotational spectrometer. The cyanovinyl radical CH₂CCN is prepared near its barrier to HCCCN + H dissociation. The observed propensity for higher energy bending vibrational state HCCCN to form faster presents is analyzed. The temperature dependence of the vibrational state specific rates provides an addition benchmark for the dynamic picture.

For more information, visit the webpage here. 

Materials with Multi-Scale Structure for Biomedical Applications

Dr. Parisa Abadi, Assistant Professor, Dept. of Mechanical Eng.; Affiliated Assistant Professor, Dept. of Biomedical Eng. & Dept. of Materials Sci. & Eng., Michigan Technological University, Houghton, MI

Abstract: Materials with multi-scale structure have many applications. In this presentation, two of the applications will be shown: nano-bioactuators and cardiomyocyte tissue engineering. In the first part, microfibers composed of hyaluronic acid hydrogel and single-wall carbon nanotubes are developed for biocompatible electrochemical microactuators and supercapacitors. Mechanically robust, flexible, and electrically conductive microfibers are obtained by wet-spinning and crosslinking of the hybrid fiber. The obtained hybrid microfibers show excellent conductivity, capacitance, and actuation behavior under low potential in a biological environment. In the second part, PDMS substrates with 3D topography at the micron and sub‐micron levels are developed and used as cell‐culture substrates to mimic the biophysical and biomechanical complexity of the native in vivo environment during the differentiation and maturation process of cardiomyocytes derived from induced pluripotent stem cells. The resulting cardiomyocytes are more similar to mature cardiomyocytes than control groups in shape, orientation, and function. New technologies such as 3D printing and new materials such as MXenes will also be discussed for the two applications.

For more information, visit the webpage here. 

Spring 2021 Schedule (PDF)

Spring 2021 Flyer (PDF)

Brochure, 5th Annual James O. Stoffer Lecture in Chemistry (digital version, PDF); Program (PDF)

Chemistry, Structure and Applications of 2D Carbides and Nitrides (MXenes) 

Dr. Yury Gogotsi, Charles T. and Ruth M. Bach Distinguished Professor of Materials Science & Engineering, Director, A.J. Drexel Nanomaterials Institute, Drexel University, Philadelphia, PA

Abstract: 2D carbides and nitrides, known as MXenes, are among the most recent, but quickly expanding material families. The field is experiencing very fast growth with the number of papers on MXenes doubling every year. Major  breakthroughs have been achieved in the past 2-3 years, including the discovery of 2D M₅C₄ carbides with the twinned layers and CVD synthesis of MoSi₂N₄, representing a new family of 2D nitrides. Synthesis of dozens of predicted MXenes, demonstration of superconductivity in MXenes with specific surface terminations, stronger interactions with electromagnetic waves compared to metals, metallic conductivity combined with hydrophilicity and redox activity, led to numerous applications. Reversible redox activity of transition metal atoms in the outer layers of MXene flakes combined with high electronic conductivity led to applications in a variety of batteries and electrochemical capacitors. MXenes are promising candidates for energy storage and related electrochemical applications, but applications in optoelectronics, plasmonics, electromagnetic interference shielding, electrocatalysis, medicine, sensors, or water purification are equally exciting.

For more information, visit the webpage here. 

Fluorescent nanodiamonds: fabrication, characterization and applications in biology

Dr. Philipp Reineck I, ARC DECRA Fellow, ARC Centre of Excellence for Nanoscale BioPhotonics, RMIT University, Melbourne, Australia

Abstract: Fluorescent nanodiamonds have unique physical, chemical and optical properties that make them highly attractive for applications from nanocomposites to quantum sensing in biology. Many different types of fluorescent nanodiamonds exist: from high-pressure high-temperature (HPHT) nanodiamonds containing engineered fluorescent defects to detonation nanodiamonds that exhibit various forms of fluorescence depending on their processing. This presentation will focus on our recent progress in areas including the creation and characterization of nitrogen, silicon and nickel-based fluorescent defects in macroscopic and nanoscale HPHT diamond, the effect of surface chemistry on nanodiamond fluorescence and the use of fluorescent nanodiamonds in composite materials and biological imaging and sensing applications. Current challenges and opportunities regarding the application of nanodiamonds in several technologies will be critically discussed.

For more information, visit the webpage here.  

Electrochemical desalination: synergy of energy storage, water remediation, and elemental recovery

Dr. Volker Presser, Professor and Chair of Energy Materials, Saarland University & INM – Leibniz Institute for New Materials, Saarbrücken, Germany

Abstract: The growing population, our increased impact on the environment, and mounting environmental impact call for a different way of storing energy and using/interacting with water resources. Reversible electrochemical processes are a promising technology for energy-efficient water treatment. Electrochemical desalination is based on the compensation of electric charge by ionic species, through which the ions are immobilized. Thereby, ions are being removed from a feed-water stream flowing through a desalination cell. For decades, electrochemical desalination has focused on using carbon electrodes, but their salt-removal ability is limited by ion electrosorption mechanism at low molar concentrations and low charge-storage capacity. Recently, charge-transfer materials, often found in batteries, have demonstrated much larger charge-storage capacities and energy-efficient desalination at low and high molar strengths. Such desalination batteries also allow for ion-specific separation, for example, to recover lithium from hydrothermal or mine water sources.

For more information, visit the webpage http://www.presser-group.com.

Self-organization and communication processes: collective response and emergence in molecular and active matter

Dr. Jerome Delhommelle, Dept. of Chem., University of North Dakota, Grand Folks, ND

Abstract: Self-organization and assembly processes are nonequilibrium phenomena that take place over a wide range of length scales and time scales. For instance, phase transitions often proceed through the nucleation of nano-sized nucleus of a new phase - a key feature for, e.g., atmospheric processes or polymorph selection in pharmaceuticals. Similarly, active, self-propelled, objects can form unexpected structures such as colloidal rotors on the micron scale or bacterial biofilms on the macroscopic scale. While recent advances in experimental, theoretical & computational methods have allowed for unprecedented insights into the behavior of nonequilibrium systems, a complete understanding of how the onset of order, change in symmetry and cooperative behavior has remained elusive. For example, it is still impossible to predict which crystal structure forms when a liquid crystallizes. This complexity arises from the interplay between different types of orders and structures. In this case, accurately sampling the underlying high-dimensional free energy surface is a formidable task. In this talk, I discuss how recent advances in statistical mechanics and algorithmic developments in numerical simulations have shed light on assembly pathways, notably through the use of novel entropy-based reaction coordinates that efficiently sample the free energy surface. I also show how data science and machine learning methods provide a way to accelerate discovery, identify novel collective variables and uncover new physics to elucidate the unexpected behaviors and emergent dynamics in these fascinating systems.

US Editor for Molecular Simulation 

Textbook Author:  A Mole of Chemistry 

Networking with faculty on April 16, 2021 at 2 - 3 pm via Zoom

James Stoffer Lecture Webinar with In-Person Audience in Leach Theatre on April 16, 2021

• Pre-registration required for in-person audience (instructions to be posted here by March 25)
• Doors open at 3:30 pm at Leach Theatre
• Stoffer Lecture begins at 4 pm;  Introductions, Lecture, Q&A
• Link to Webinar: https://umsystem.zoom.us/j/94628802660

The Origins of the Lithium Battery and Future Chemistry and Materials Challenges 

Dr. Stanley Whittingham, SUNY Distinguished Professor & 2019 Nobel Laureate, Binghamton University

Abstract: The success of lithium-ions arose from a fundamental understanding of what controls fast ion transport in solids. Intercalation reactions have been the basis of all rechargeable lithium batteries since their inception 50 years ago, because usually these result in less structural change and the compounds show high solubility for lithium ions, as in Li_xTiS₂ , where 0≤x≤1. However, 40+ years later, commercial cells attain only 25% of their theoretical energy densities. The dominant NMCA cathodes can now attain over 200 Wh/kg commercially at the cell level, and the Battery500 consortium has attained around 350 Wh/kg in full cells, out of a theoretical 1000 Wh/kg. The scientific challenges to improving the energy density will be discussed; these include the need for higher ionic and electronic conductivities, as well as greater stability of the solid materials and the liquid or solid electrolytes.

For more information, visit the webpage here. To view the recording of the event, click here. 

Fall 2020 (PDF)

Science Ethics, Goals and Aspirations in Times of a Pandemic

Dr. Rainer Glaser, Chair, Dept. of Chemistry, Missouri S&T

Abstract: The S&T Department of Chemistry is a dynamic organization with complex interactions between material infrastructure and staff support, a diverse population of undergraduate, graduate and post-doctoral students, and an international faculty. Modern science is a global enterprise adding an exciting and mutually enriching cross-cultural component to the complexity. The department’s success depends on synergy across all of its components, common ethics, shared goals, and shared aspirations. The global pandemic presents an added challenge and reinforces the need for clarity on ethics. Our scientific creed requires curiosity, energy, initiative, and excellence in interdisciplinary science and the development of skills, knowledge and abilities to optimize teamwork, responsible conduct of research, and the interrelations between the teaching, research and service missions. In this presentation, we will address some of the strengths and some of the challenges with regard to departmental infrastructure and personnel, chemistry instrumentation, faculty and scientific staff, and the evolution of the undergraduate and graduate programs. Practical proposals will be presented to facilitate the gradual evolution towards our shared goals.

For more information, visit the webpage here. 

Networking with faculty and students at 1:45 – 3 pm at the Colloquium ZOOM link

Ozone Reaction Problems in Modern Aquariums

Dr. Michael D. Stafford, DVM, American National Fish and Wildlife Museum

Abstract: There are over 200 aquariums worldwide with the largest being over 14 million gallons. Wonders of Wildlife in Springfield Missouri has 1.5 million gallons and Bass Pro shops has over 230 individual systems comprising 1.7 million gallons. Modern aquariums typically use multiple systems to maintain water quality and clarity. Ozone, a powerful oxidizer, has been added to the arsenal to flocculate and remove organics thereby enhancing water clarity. This has created an issue with the health of the animals. In freshwater systems with ozone, we are seeing epithelial erosion over the bony plates and lateral line. We are trying to determine what this process is. Essentially, are we creating an irritant or are we stripping away an essential nutrient? This lecture will present the problem with the hopes of collaborating with an interested individual(s) in solving the issue.

For more information about the American National Fish and Wildlife Museum, please visit wondersofwildlife. 

Exploring Chemical Physics in Transient Plasma by Broadband Rotational Spectroscopy

Dr. Nick Walker, Senior Lecturer at Newcastle University at Newcastle upon Tyne, UK

Abstract: Rotational spectroscopy provides unrivaled precision for the determination of molecular structure in isolated, gas phase species. Electronics capable of digitizing waveforms at gigahertz frequencies now allows chirped-pulse Fourier transform microwave spectroscopy¹ to be performed at high resolution, high bandwidth and with minimal or no cost to sensitivity. Two approaches are possible. Specific molecules or complexes can be targeted and selectively generated for study through a careful choice of appropriate precursors. Alternatively, a survey of chemical products generated under selected environmental conditions can be performed in an approach termed “broadband reaction screening”.² Each of these approaches will be described during this presentation.

One focus will be experiments that have applied broadband rotational spectroscopy to probe interactions between isolated, metal-containing molecules and simple hydrocarbons such as ethene, ethyne and cyclopropane.³ The complexes are generated through laser vaporization of a metal target in the presence of an expanding gas sample containing the hydrocarbon precursor. Precise changes in the geometry of the hydrocarbons on their attachment to copper, silver and gold atoms will be described. The products of chemical reactions between platinum, palladium and hydrocarbons following laser vaporization of the metal in the presence of a hydrocarbon precursor have also been characterized. It will be shown that many choices of hydrocarbon allow the efficient generation⁴ of linear PtC₃ or PdC₃ units within the transient plasma. It will also be shown that the method provides a new and powerful approach through which to explore the gas phase chemistry between platinum, palladium and hydrocarbons.   

For more information, visit the webpage here. 

Coherent population transfer in chiral molecules using tailored microwave pulses

Dr. Melanie Schnell, Professor of Physical Chemistry, Christian-Albrechts-Universität zu Kiel;  Leading Scientist at Deutsches Elektronen-Synchrotron of the “Spectroscopy of Molecular Processes” group, Germany

Abstract: Most molecules of biochemical relevance are chiral. Even though the physical properties of two enantiomers are nearly identical, they can exhibit completely different biochemical effects, such as different odor in the case of carvone. In nature and as products of chemical syntheses, chiral molecules often exist in mixtures with other chiral species. The analysis of these complex mixtures to identify the molecular components, to determine which enantiomers are present, and to measure the enantiomeric excesses (ee) remains a challenging task for analytical chemistry.

In collaboration with Dave Patterson (UCSB) and John Doyle (Harvard University), we recently experimentally demonstrated a new method of differentiating enantiomeric pairs of chiral molecules in the gas phase. It is based on broadband rotational spectroscopy and is a three-wave mixing process that involves a closed cycle of three rotational transitions. The phase of the acquired signal bares the signature of the enantiomer, as it depends upon the product of the transition dipole moments, and the signal amplitude is proportional to the ee. A unique advantage of our technique is that it can also be applied to mixtures of chiral molecules, even when the molecules are very similar. It also bears the potential for enantiomer separation, as was recently shown in experiments on enantiomer-selective population transfer. In my lecture, I will introduce the technique and give an update on the recent developments.

For more information, visit the webpage here. 

Networking with faculty at 9 - 10 am via Zoom.

Carboline:  Global Supplier of Industrial Coatings, Linings and Passive Fire Protection

Mary Roley, Technical Director, Innovation; Jeff Anderson, Vice President, Research, Development and Innovation; Steve Bockhold, Carboline Company, Saint Louis

Abstract: The presentation will discuss our career paths from undergrad to our current position. A discussion of industrial chemistry as well as types of jobs. Overview of Carboline, products we produce, and chemistry we apply. Internship opportunities at Carboline.

For more information, visit the webpage here. 

 Spring 2020 (PDF)

Using Direct Analyte Probe Nanoextraction (DAPNe) and Nanoparticle Deposition-coupled to MALDI to exact chemical information from one cell and one organelle 

Dr. Guido Verbeck, IV, Prof. of Chemistry and Biochemistry, Univ. of North Texas

Abstract: Typical cellular chemical analysis employs the application of lysing groups of cells to observe biomolecules of interest in their roles of metabolic processes. This approach destroys the cells analyzed and does not allow for true one-cell chemistry to be determined. Individual cells have unique physiologies and produce different metabolites even within cells of the same tissue. As such, a method for investigating a single cell without destroying it or surrounding cells is desired to further understand these unique cellular processes. Recently, the application of directing femtosecond laser pulses at cell membranes to create sub-micron dissections has been accomplished. This novel method leaves cellular chemistry unaltered, and in combination with nanomanipulation and Raman microscopy, a novel bioworkstation was developed, capable of providing accurate and localized one-cell chemical analysis. Our group has demonstrated the capabilities of this workstation via nanoextraction of adipocytes from tumorous and healthy breast tissue with the nanomanipulator and utilizing nanoparticle deposition for MALDI small molecule analysis. Preliminary data suggests that the triglyceride make-up appears to be influenced by the cellular location within a tissue, evident by the ratios of three triglyceride peaks identified in each cell. The lipid heterogeneity identified here supports the notion that specific fatty acids may play a role in tumor cell proliferation, however the mechanism is currently unknown thus further investigation is warranted.

•Create a clinical/pathology tool for more accurate precancer screening

•True one-cell biomarker discovery

•Explore biochemical pathways and one-cell life cycles

•Understanding accurate one-cell nature in a heterogeneous tissue sample

•Ability to extract the metabolome with the RNA for upregulation in true one-cell

•Ability to extract both lipophilic and hydrophilic metabolites in drugs in one extraction

For more information, visit the webpage here. Find the itinerary of the visit here. 

Green chemistry to the rescue of materials synthesis 

Dr. Jerome Claverie, Dept. of Chemistry, University of Sherbrooke

Abstract:  Green chemistry has recently revolutionized the way we think about synthesis. However, most common organic materials have been conceived at times when environmental concerns and green chemistry concepts were often overlooked. In this lecture, we will present our efforts to design novel materials with usage properties that equal or surpass those existing, by strictly adhering to the principles of green chemistry. We will first present our efforts to prepare functional polymers by catalytic means, and using biosourced raw materials. We will then present an aqueous encapsulation process that is very versatile for the preparation of nanocomposites. The resulting nanocomposites are excellent catalysts for artificial photosynthesis and the oxygen reduction reaction (ORR).

For more information, visit the webpage here.  Find the itinerary of the visit here. 

Sensitization of Oxide Single Crystals with Quantum Confined Semiconductors 

Bruce Parkinson, Professor of Chemistry & Energy Resources, Univ. of Wyoming

Abstract:  We study the fundamentals of electron injection by molecules, quantum dots, quantum confined nanoplatelets and semiconducting nanotubes into large bandgap metal oxide semiconductors and gallium phosphide. We have been testing a theoretical model that predicts that the photocurrent yields and photocurrent-voltage behavior are controlled by the doping density that then determines the field gradient of the Schottky barrier at the electrode/electrolyte interface. The model was shown to be applicable to sensitization by both thiacyanine and ruthenium based sensitizing dyes with the difference of the behavior between the two classes of dyes being attributed to the different distance of the photogenerated hole on the dye from the injected electron that influences the rate of the back reaction. We have extended these studies to monolayers of adsorbed CdSe quantum dots (QDs) of various sizes on well- characterized TiO 2 single crystals with varying doping densities. We are also building on our previous work where we were able to observe sensitized photocurrent quantum yields >1 from multiple exciton generation and collection from PbS quantum dots adsorbed on single crystal anatase electrodes and are working on preparation of InSb QDs that may be capable of producing 3 excitons per high energy photon.

For more information, visit the webpage here. Find the itinerary of the visit here. 

Two-dimensional Transition Metal Carbides and Carbonitrides for Electrochemical Energy Storage and Conversion 

Michael Naguib, Asst. Prof. of Physics and Engineering, Tulane University

Abstract: MXenes are large family of two-dimensional (2D) transition metal carbides and nitrides of M _n+1X _nT _z composition; where M is an early transition metal (e.g. Ti, V, Mo, Nb) and X is either carbon or nitrogen, “T _z ” stands for a mixture of surface terminations (e.g. O, OH, F, Cl), and n can be 1, 2, or 3. So far, about two dozens of MXenes have been produced experimentally (e.g. Ti₃C₂ , V₂C, Nb₂C, Mo₂C, (V_0.5 ,Cr_0.5 )₃C₂ , Ti₃CN, Ta₄C₃ , and Nb₄C₃ ). In addition, ab initio calculations predicted many others to be stable. Combining the metallic conductivity of transition metal carbide/nitrides with the hydrophilic nature of their terminated surfaces place MXenes in a unique position among all other 2D materials. MXenes can be intercalated by a wide range of intercalants from mono- and multi-valent ions to organic and inorganic molecules. Since their discovery, intercalation has been of a critical importance for MXenes processing and applications including electrochemical energy storage, water purification and sensing. However, very little has been known for the nature of intercalant and the bonding between MXenes surface and the intercalant. Using various neutron scattering techniques, we studied MXenes intercalation for two systems: Ti₃C₂ /ion/water and Ti₃C₂/urea/water. In this presentation, the recent fundamental findings and understanding for the complexity of intercalations in MXenes, will be discussed. In addition, the performance of MXenes as electrode materials hosting ions for batteries and supercapacitors and their performance as electrocatalyst will be presented.

For more information, visit the webpage here.

Organic Chemistry in Harsh Reaction Environments 

Robert McMahon, Prof. of Chemistry, Univ. of Wisconsin-Madison

Abstract:  Our research efforts focus on elucidating the chemistry and spectroscopy of organic species that are postulated to play a role in harsh environments (e.g. combustion, planetary atmospheres, interstellar space). These environments contain a remarkable diversity of organic functionality, including reactive intermediates such as anions, radicals, and carbenes. We have drawn on our knowledge of mechanistic and structural organic chemistry to identify chemically-significant targets for detection and characterization. Many of these investigations are made possible through our ability to prepare specific chemical precursor molecules via synthetic organic chemistry. I will present case studies that exemplify how modern physical-organic chemistry spans the disciplines of organic chemistry, chemical physics, and astronomy.

For more information, visit the webpage here. 

Development and Fundamental Understanding of the World’s Most Versatile Polymers, Polybenzoxazine: From Smart to Extreme Property  

Hatsuo Ishida, Distinguished Research Professor of Macromolecular Science and Engineering, Case Western Univ.

Abstract: We are now in the dark age of commercialization of new polymers. In the past 40 years, only a few new polymers have been commercialized. The subject of the lecture, polybenzoxazine, is one of them. It is an extremely versatile material that can be readily synthetized from off-the-shelf commercially available raw materials, and the material can be easily tailored to the desired properties. They can also be synthesized from many natural renewable raw materials, such as cashew nut shell oil, vanillin, chitosan, and furfural amine. Polybenzoxazines exhibit several unusual properties other polymers do not show, including surface free energy lower than Teflon without fluorine atoms, extremely high char yield, near-zero shrinkage upon polymerization, and property increase at low conversions. Polybenzoxazines defy the common wisdom of “the higher the properties, the more expensive and difficult to process,” It can be easily processed like an epoxy resin, and show an unusual “polymerization temperature; Tg” relationship. Utilizing these advantageous and very versatile properties, we have been developing a number of materials that can be applied to many potential fields, such as aerospace, electronic, automotive, coating, catalysis and many others. The lecture introduces fundamental unique chemistry of benzoxazine polymerization, and development of smart, high-performance and extreme-performance materials.

For more information, visit the webpage here.

Fall 2019 (PDF)

Science Ethics, Goals and Aspirations

Dr. Rainer Glaser, Chair, Dept. of Chemistry, MS&T

Abstract: The S&T Department of Chemistry is a dynamic organization with complex interactions between material infrastructure and staff support, a diverse population of undergraduate, graduate and post-doctoral students, and an international faculty. Modern science is a global enterprise adding an exciting and mutually enriching cross-cultural component to the complexity. The department’s success depends on synergy across all of its components, common ethics, shared goals, and shared aspirations. Our scientific creed requires curiosity, energy, initiative, and excellence in interdisciplinary science and the development of skills, knowledge and abilities to optimize teamwork, responsible conduct of research, and the interrelations between the teaching, research and service missions. In this presentation, we will address some of the strengths and some of the challenges with regard to departmental infrastructure and personnel, chemistry instrumentation, faculty and scientific staff, and the evolution of the undergraduate and graduate programs. Practical proposals will be presented to facilitate the gradual evolution towards our shared goals.

For more information, visit the webpage here.

Quantitative NMR to Measure Drug Release from Pharmaceutical Formulations

Dr. Nathan Oyler, Assoc. Prof. of Chemistry, UMKC

Abstract: Accurately assaying the amount of drug released (as a function of time) in human bodily fluids is a crucial requirement of the drug formulation development process (i.e. developing the matrix to enclose the drug).  Classically, a method combining dialysis (to separate the released drug from the bodily fluid) and HPLC (to quantify the amount of drug) is commonly used due, in part, to its high sensitivity, but here we demonstrate a more direct, while still accurate method to determine the real-time release using quantitative NMR.  The fundamental NMR concepts that makes the method possible will be discussed, and directly detected real-time drug release profiles of drug formulations dissolved in simulated bodily fluids will be presented. Additionally, the extensibility of the methods to other drugs/formulations will be discussed.

For more information, visit the webpage here. Find the itinerary of the visit here. 

The Challenge of Organic Radical Design for Materials, Biomedicine, and Biophysics

Dr. Andrzej Rajca, Charles Bessey Professor of Chemistry, University

Abstract: Open-shell organic molecules and polymers, with well-defined spin-spin interactions, are becoming more prominent building blocks for materials, as well as for applications in biomedicine and biophysics. Stability of organic radicals at room temperature and above is essential for their applications, and for biomedical applications and for emerging biophysical applications, the radicals should be highly resistant to the reduction in vivo. Design of organic paramagnetic compounds that require optimization of multiple properties has proven to be a challenge. This lecture will describe the design of organic radicals with well-defined structures that are tailored to specific target properties for organic magnets, contrast agents for magnetic resonance imaging, dynamic nuclear polarization (DNP) NMR enhancement agents, and spin labels for distance measurements in proteins.

For more information, visit the webpage here. Find the itinerary of the visit here. 

Repairing the Body with Glass

Dr. Delbert Day, Curator’s Professor Emeritus Of Ceramic Engineering, S&T

Abstract: As I thought about a topic for this lecture, I immediately thought of the material we call glass and how mankind has benefited from this remarkable and fascinating material for thousands of years.  We all benefit from the glass windows and insulation in our homes, sky scrapers, vehicles and airplanes.  We use a wide range of glass containers (bottles) of all sizes and shapes.  Glass is an important component of electronic devices such as cell phones, radios, and flat screen TV’s.

Fortunately, new and surprising uses for glass also are constantly being found.  Thus, the title of my lecture today is “Repairing the Body with Glass.”  I would like to share with you two examples of how glasses of special composition are being used to repair medical conditions in the human body.  The first example describes how bioinert glass microspheres are now being used world-wide to treat patients with inoperable liver cancer.  The second example shows how bioactive glass fibers are being used to treat patients with chronic, non-healing wounds.

For more information, visit the webpage here. 

Nuclear Magnetic Resonance (NMR) Strategies for Understanding Nanoparticle Surface Interactions 

Dr. Leah Casabianca, Assoc. Prof. of Chemistry, Clemson University

Abstract: Nanotechnology is becoming increasingly prevalent in our everyday lives. Nanoparticles that are used as lubricants, in drug delivery, and as antibacterial agents are finding their way into the body and into the environment, where they interact with biological macromolecules such as proteins. Understanding the nature of the interactions between nanoparticles and absorbed
molecules is therefore increasingly relevant in fields such as drug delivery, nanoparticle catalysis, and nanoparticle toxicity. In this talk, I will discuss several recent studies in my lab that are aimed at developing solution-state Nuclear Magnetic Resonance (NMR) techniques for studying noncovalent nanoparticle surface interactions.

NMR is an incredibly powerful characterization technique, capable of providing atomic-level structural as well as dynamic information. However, NMR is not ideally suited for surface studies due to the inherent low sensitivity of this technique. One way of improving the sensitivity of NMR is Dynamic Nuclear Polarization (DNP). DNP relies on the transfer of polarization from a nearby unpaired electron to nuclei of interest in NMR. My group has recently 1 developed Highly-effective Polymer/Radical Beads (HYPR-Beads), which are organic nanoparticles that have been doped with radicals for use as DNP polarization agents. Using HYPR-beads, we were able to hyperpolarize nuclei in small molecules that are located near the beads in an aqueous environment.

We are also using Saturation Transfer Difference (STD)-NMR Spectroscopy to identify small molecules that interact noncovalently with the surface of functionalized organic nanoparticles in solution. 2 STD-NMR was originally developed to identify small-molecule ligands that bind to a protein receptor. Since this technique does not require the receptor to be seen by solution-state NMR, there is no upper limit to the size of the receptor that can be studied. This makes the STD-NMR technique an ideal one to study small molecules adsorbed on the surface of nanoparticles. We have used STD-NMR to examine the binding between small molecules and
solvent water on the surface of nanoparticles, 2 to screen individual amino acids for binding to the nanoparticle surface, 3 and to determine the binding epitopes of a fluorescent dye associating with the nanoparticle surface. 4 This work has future applications in determining the structure of proteins adsorbed on the surface of nanoparticles, and in the development of dual-use (for example fluorescence and magnetic resonance) imaging contrast agents.

For more information, visit the webpage here.  Find the itinerary of the visit here. 

Charge Carrier Dynamics in Nanostructures Studied by Femtosecond Laser Spectroscopy 

Dr. Jinjun Liu, Assoc. Prof. of Chemistry, University of Louisville

Abstract: Ultrafast laser spectroscopy is a powerful tool for the investigation of charge and energy transfer processes in molecules and condensed-phase materials. Our research group uses femtosecond transient absorption (TA) technique to study charge carrier dynamics in nanomaterials. In this talk, I will first introduce the principles of the ultrafast TA spectroscopy. Results from two recent projects will be presented to illustrate the effectiveness and limits of the spectroscopic technique. In the first, femtosecond TA spectroscopy was employed to investigate photoinduced exciton dynamics in three novel CH 3 NH 3 PbBr 3 perovskite nanostructures: nanocrystals (0D), nanowires (1D), and nanoplatelets (2D). Time scales of different charge carrier processes were determined in the experiment. It has been found in our work that the excition recombination process obeys the rate law of a second-order reaction, but the rate constant depends strongly on the initial charge carrier desnitry and the morphology of the nanostructures. In the second experiment, excited-stat dynamics of molecule-like ligand-passivated (CdSe) 34 nanoclusters (d=1.6 nm) was monitored by femtosecond TA spectroscopy. In addition, sub-picosecond hole transfer from a nanocluster to its strongly bound ligand shell was observed. A second sub-picosecond process in the TA spectra was attributed to "hot" electron transfer to interfacial states created by charge separation. THe critical role of energy level alignment between the semiconductor nanocluster and its passivating ligands has been confirmed in a series of control experiments. Understanding charge carrier dynamics in nanostructures and on their interfaces can aid in the design of high-efficiency photovoltaic and light-emitting devices.

For more information, visit the webpage here. Find the itinerary of the visit here.