School of Humanities and Sciences


Showing 51-100 of 382 Results

  • Xiaoke Chen

    Xiaoke Chen

    Associate Professor of Biology

    Current Research and Scholarly InterestsOur goal is to understand how brain circuits mediate motivated behaviors and how maladaptive changes in these circuits cause mood disorders. To achieve this goal, we focus on studying the neural circuits for pain and addiction, as both trigger highly motivated behaviors, whereas, transitioning from acute to chronic pain or from recreational to compulsive drug use involves maladaptive changes of the underlying neuronal circuitry.

  • Christopher Chidsey

    Christopher Chidsey

    Associate Professor of Chemistry, Emeritus

    Current Research and Scholarly InterestsThe Chidsey group research interest is to build the chemical base for molecular electronics. To accomplish this, we synthesize the molecular and nanoscopic systems, build the analytical tools and develop the theoretical understanding with which to study electron transfer between electrodes and among redox species through insulating molecular bridges

  • Ching Chieh Chou

    Ching Chieh Chou

    Basic Life Res Scientist

    Current Research and Scholarly InterestsI am interested in the cellular strategies to regulate protein folding, transport and aggregation, and the pathogenic pathways leading to proteome remodeling in age-related neurodegenerative diseases. I use molecular imaging, cell reprogramming and multi-omics technologies to address these questions with importance to the aging and neuroscience field.

  • Steven Chu

    Steven Chu

    William R. Kenan Jr. Professor, Professor of Molecular and Cellular Physiology and of Energy Science and Engineering

    Current Research and Scholarly InterestsSynthesis, functionalization and applications of nanoparticle bioprobes for molecular cellular in vivo imaging in biology and biomedicine. Linear and nonlinear difference frequency mixing ultrasound imaging. Lithium metal-sulfur batteries, new approaches to electrochemical splitting of water. CO2 reduction, lithium extraction from salt water

  • Sarah Church

    Sarah Church

    Professor of Physics
    On Leave from 01/01/2024

    Current Research and Scholarly InterestsExperimental & Observational Astrophysics and Cosmology

  • James Collman

    James Collman

    George A. and Hilda M. Daubert Professor of Chemistry, Emeritus

    BioProfessor Emeritus James Collman has made landmark contributions to inorganic chemistry, metal ion biochemistry, homogeneous catalysis, and transition metal organometallic chemistry. He pioneered numerous now-popular research tools to reveal key structural and functional details of metalloenzymes essential to respiration and energy, and hemoglobin and myoglobin, essential to oxygen transport in the blood.

    Born 1932 in Beatrice, Nebraska, James P. Collman studied chemistry at U. Nebraska–Lincoln (B.S. 1954, M.S. 1956). His doctoral work at U. Illinois at Urbana-Champaign (Ph.D., 1958) focused on Grignard reagents. As a faculty member at U. North Carolina, he demonstrated aromatic reactivity in metal acetylacetonates, and he developed metal complexes that hydrolyze peptide bonds under physiological conditions. He came to Stanford University as Professor of Chemistry in 1967. Among many honors, Prof. Collman’s was elected to the National academy of Sciences in 1975, and named California Scientist of the Year in 1983.

    At Stanford, Prof. Collman invented a new paradigm for studying biological systems using functional synthetic analogs of metal-containing enzyme systems, free from the protein coatings that can affect metalloprotein chemical properties. This strategy allowed him to elucidate the intrinsic reactivity of the metal center as well as the effects of protein-metal interactions on biological function.

    One focal point of this research has involved heme-proteins such as the oxygen (O2) carrier hemoglobin (Hb), and the O2-storing protein myoglobin (Mb). Prof. Collman was the first to prepare and characterize stable, functional analogues of the Hb and Mb active sites, which contain an iron derivative of the large flat “porphyrin” ligand. In his “picket fence” porphyrin, groups installed on the periphery block side reactions, which would otherwise degrade the structure. This protected iron complex manifests the unique magnetic, spectroscopic and structural characteristics of the O2-binding Hb and Mb sites, and exhibits very similar O2-binding affinities.

    The Collman Group also prepared functional mimics of the O2-binding/reducing site in a key respiration enzyme, cytochrome c oxidase, CcO, which converts O2 to H2O during biosynthesis of the energy storage molecule ATP. This enzyme must be very selective: partial O2 reduction products are toxic. Prof. Collman invented a powerful synthetic strategy to create analogs of the CcO active site and applied novel electrochemical techniques to demonstrate that these models catalyze the reduction of O2 to water without producing toxic partially-reduced species. He was able to mimic slow, rate-limiting electron delivery by attaching his CcO model to a liquid-crystalline membrane using “click chemistry.” He demonstrated that hydrogen sulfide molecules and heterocycles reversibly bind to the metal centers at CcO’s active site, connecting a synthetic enzyme model to simple molecules that reversibly inhibit respiration. These respiration inhibitors exhibit physiological properties, affecting blood clotting and controlling the effects of the hormone, nitric oxide, NO.

    In addition, Prof. Collman performed fundamental studies of organometallic reactions. He also prepared and characterized homodinuclear and heterodinuclear complexes having metal-metal multiple bonds, and made the first measurements of the rotational barriers found in multiple metal-metal bonds.

    Prof. Collman’s impactful textbook “Principles and Applications of Organotransition Metal Chemistry” has seen multiple editions. His book “Naturally Dangerous: Surprising Facts About Food, Health, and the Environment” explains the science behind everyday life, and received favorable reviews in Nature and The Washington Post.

  • Jonas Cremer

    Jonas Cremer

    Assistant Professor of Biology

    Current Research and Scholarly InterestsWe are a highly interdisciplinary research team, joined in our desire to better understand microbial life. To elucidate how bacterial cells accumulate biomass and grow, we work with the model organism Escherichia coli. We further focus on gut bacteria and their interactions with the human host. Our approaches combine quantitative experimentation and mathematical modeling.

  • Larry Crowder

    Larry Crowder

    Edward Ricketts Provostial Professor, Professor of Oceans, Senior Fellow at the Woods Institute for the Environment and Professor, by courtesy, of Biology

    Current Research and Scholarly InterestsEcology, conservation, fisheries, protected species, ecosystem-based management

  • Bianxiao Cui

    Bianxiao Cui

    Job and Gertrud Tamaki Professor of Chemistry

    Current Research and Scholarly InterestsOur objective is to develop new biophysical methods to advance current understandings of cellular machinery in the complicated environment of living cells. Currently, we are focusing on four research areas: (1) Membrane curvature at the nano-bio interface; (2) Nanoelectrode arrays (NEAs) for scalable intracellular electrophysiology; (3) Electrochromic optical recording (ECORE) for neuroscience; and (4) Optical control of neurotrophin receptor tyrosine kinases.

  • Yi Cui

    Yi Cui

    Fortinet Founders Professor, Professor of Materials Science and Engineering, of Energy Science and Engineering, of Photon Science, Senior Fellow at Woods and Professor, by courtesy, of Chemistry

    BioCui studies fundamentals and applications of nanomaterials and develops tools for their understanding. Research Interests: nanotechnology, batteries, electrocatalysis, wearables, 2D materials, environmental technology (water, air, soil), cryogenic electron microscopy.

  • Martha S. Cyert

    Martha S. Cyert

    Dr. Nancy Chang Professor

    Current Research and Scholarly InterestsThe Cyert lab is identifying signaling networks for calcineurin, the conserved Ca2+/calmodulin-dependent phosphatase, and target of immunosuppressants FK506 and cyclosporin A, in yeast and mammals. Cell biological investigations of target dephosphorylation reveal calcineurin’s many physiological functions. Roles for short linear peptide motifs, or SLiMs, in substrate recognition, network evolution, and regulation of calcineurin activity are being studied.

  • Hongjie Dai

    Hongjie Dai

    The J.G. Jackson and C.J. Wood Professor of Chemistry, Emeritus

    BioProfessor Dai’s research spans chemistry, physics, and materials and biomedical sciences, leading to materials with properties useful in electronics, energy storage and biomedicine. Recent developments include near-infrared-II fluorescence imaging, ultra-sensitive diagnostic assays, a fast-charging aluminum battery and inexpensive electrocatalysts that split water into oxygen and hydrogen fuels.

    Born in 1966 in Shaoyang, China, Hongjie Dai began his formal studies in physics at Tsinghua U. (B.S. 1989) and applied sciences at Columbia U. (M.S. 1991). He obtained his Ph.D. from Harvard U and performed postdoctoral research with Dr. Richard Smalley. He joined the Stanford faculty in 1997, and in 2007 was named Jackson–Wood Professor of Chemistry. Among many awards, he has been recognized with the ACS Pure Chemistry Award, APS McGroddy Prize for New Materials, Julius Springer Prize for Applied Physics and Materials Research Society Mid-Career Award. He has been elected to the American Academy of Arts and Sciences, National Academy of Sciences (NAS), National Academy of Medicine (NAM) and Foreign Member of Chinese Academy of Sciences.

    The Dai Laboratory has advanced the synthesis and basic understanding of carbon nanomaterials and applications in nanoelectronics, nanomedicine, energy storage and electrocatalysis.

    Nanomaterials
    The Dai Lab pioneered some of the now-widespread uses of chemical vapor deposition for carbon nanotube (CNT) growth, including vertically aligned nanotubes and patterned growth of single-walled CNTs on wafer substrates, facilitating fundamental studies of their intrinsic properties. The group developed the synthesis of graphene nanoribbons, and of nanocrystals and nanoparticles on CNTs and graphene with controlled degrees of oxidation, producing a class of strongly coupled hybrid materials with advanced properties for electrochemistry, electrocatalysis and photocatalysis. The lab’s synthesis of a novel plasmonic gold film has enhanced near-infrared fluorescence up to 100-fold, enabling ultra-sensitive assays of disease biomarkers.

    Nanoscale Physics and Electronics
    High quality nanotubes from his group’s synthesis are widely used to investigate the electrical, mechanical, optical, electro-mechanical and thermal properties of quasi-one-dimensional systems. Lab members have studied ballistic electron transport in nanotubes and demonstrated nanotube-based nanosensors, Pd ohmic contacts and ballistic field effect transistors with integrated high-kappa dielectrics.

    Nanomedicine and NIR-II Imaging
    Advancing biological research with CNTs and nano-graphene, group members have developed π–π stacking non-covalent functionalization chemistry, molecular cellular delivery (drugs, proteins and siRNA), in vivo anti-cancer drug delivery and in vivo photothermal ablation of cancer. Using nanotubes as novel contrast agents, lab collaborations have developed in vitro and in vivo Raman, photoacoustic and fluorescence imaging. Lab members have exploited the physics of reduced light scattering in the near-infrared-II (1000-1700nm) window and pioneered NIR-II fluorescence imaging to increase tissue penetration depth in vivo. Video-rate NIR-II imaging can measure blood flow in single vessels in real time. The lab has developed novel NIR-II fluorescence agents, including CNTs, quantum dots, conjugated polymers and small organic dyes with promise for clinical translation.

    Electrocatalysis and Batteries
    The Dai group’s nanocarbon–inorganic particle hybrid materials have opened new directions in energy research. Advances include electrocatalysts for oxygen reduction and water splitting catalysts including NiFe layered-double-hydroxide for oxygen evolution. Recently, the group also demonstrated an aluminum ion battery with graphite cathodes and ionic liquid electrolytes, a substantial breakthrough in battery science.

  • Barnabas Daru

    Barnabas Daru

    Assistant Professor of Biology and Center Fellow, by courtesy, at the Woods Institute for the Environment

    BioBarnabas Daru is an Assistant Professor of Biology. He is interested in the ecology and biogeography of plants across ecological scales. He studied botany in Johannesburg, and was a postdoctoral researcher at Harvard, where he worked on new uses of herbarium specimens for understanding plant ecology and evolution in the Anthropocene, the epoch of profound human impact on Earth. Current research in the Daru lab addresses the role of phylogeny in: 1) understanding how species are distributed, 2) conserving unique communities, and 3) understanding changing distributions in the Anthropocene.

  • Laura M.K. Dassama

    Laura M.K. Dassama

    Assistant Professor of Chemistry and of Microbiology and Immunology

    BioLaura Dassama is a chemical biologist who uses principles from chemistry and physics to understand complex biological phenomena, and to leverage that understanding for the modulation of biological processes. Her current research focuses on deciphering the molecular recognition mechanisms of multidrug transporters implicated in drug resistance, rational engineering and repurposing of natural products, and control of transcription factors relevant to sickle cell disease.

  • Giulio De Leo

    Giulio De Leo

    Professor of Oceans, of Earth System Science, Senior Fellow at the Woods Institute for the Environment and Professor, by courtesy of Biology

    Current Research and Scholarly InterestsI am a theoretical ecologist mostly interested in investigating factors and processes driving the dynamics of natural and harvested populations and on how to use this knowledge to inform practical management. I have worked broadly on life histories analysis, fishery management, dynamics and control of infectious diseases and environmental impact assessment.

  • Joseph M. DeSimone

    Joseph M. DeSimone

    Sanjiv Sam Gambhir Professor of Translational Medicine, Professor of Chemical Engineering and, by courtesy, of Chemistry, of Materials Science and Engineering, and of Operations, Information and Technology at the Graduate School of Business

    BioJoseph M. DeSimone is the Sanjiv Sam Gambhir Professor of Translational Medicine and Chemical Engineering at Stanford University. He holds appointments in the Departments of Radiology and Chemical Engineering with courtesy appointments in the Department of Chemistry and in Stanford’s Graduate School of Business.

    The DeSimone laboratory's research efforts are focused on developing innovative, interdisciplinary solutions to complex problems centered around advanced polymer 3D fabrication methods. In Chemical Engineering and Materials Science, the lab is pursuing new capabilities in digital 3D printing, as well as the synthesis of new polymers for use in advanced additive technologies. In Translational Medicine, research is focused on exploiting 3D digital fabrication tools to engineer new vaccine platforms, enhanced drug delivery approaches, and improved medical devices for numerous conditions, with a current major focus in pediatrics. Complementing these research areas, the DeSimone group has a third focus in Entrepreneurship, Digital Transformation, and Manufacturing.

    Before joining Stanford in 2020, DeSimone was a professor of chemistry at the University of North Carolina at Chapel Hill and of chemical engineering at North Carolina State University. He is also Co-founder, Board Chair, and former CEO (2014 - 2019) of the additive manufacturing company, Carbon. DeSimone is responsible for numerous breakthroughs in his career in areas including green chemistry, medical devices, nanomedicine, and 3D printing. He has published over 350 scientific articles and is a named inventor on over 200 issued patents. Additionally, he has mentored 80 students through Ph.D. completion in his career, half of whom are women and members of underrepresented groups in STEM.

    In 2016 DeSimone was recognized by President Barack Obama with the National Medal of Technology and Innovation, the highest U.S. honor for achievement and leadership in advancing technological progress. He has received numerous other major awards in his career, including the U.S. Presidential Green Chemistry Challenge Award (1997); the American Chemical Society Award for Creative Invention (2005); the Lemelson-MIT Prize (2008); the NIH Director’s Pioneer Award (2009); the AAAS Mentor Award (2010); the Heinz Award for Technology, the Economy and Employment (2017); the Wilhelm Exner Medal (2019); the EY Entrepreneur of the Year Award (2019 U.S. Overall National Winner); and the Harvey Prize in Science and Technology (2020). He is one of only 25 individuals elected to all three branches of the U.S. National Academies (Sciences, Medicine, Engineering). DeSimone received his B.S. in Chemistry in 1986 from Ursinus College and his Ph.D. in Chemistry in 1990 from Virginia Tech.

  • Trithep Devakul

    Trithep Devakul

    Assistant Professor of Physics

    BioI am a theoretical condensed matter physicist. My general research interests lie in exploring all the exotic states of matter that can arise in quantum systems.

    I am currently interested in studying topological states that can arise in a class of 2D quantum materials known as moiré materials.

    I did my bachelor's at Northeastern, a PhD at Princeton, and a postdoc at MIT, before joining Stanford as an assistant professor. I grew up in Bangkok, Thailand.

  • Persi Diaconis

    Persi Diaconis

    Mary V. Sunseri Professor in the School of Humanities and Sciences and Professor of Mathematics

    Current Research and Scholarly InterestsResearch Interests:
    PROBABILITY THEORY
    BAYESIAN STATISTICS
    STATISTICAL COMPUTING
    COMBINATORICS

  • Savas Dimopoulos

    Savas Dimopoulos

    Hamamoto Family Professor

    BioWhat is the origin of mass? Are there other universes with different physical laws?

    Professor Dimopoulos has been searching for answers to some of the deepest mysteries of nature. Why is gravity so weak? Do elementary particles have substructure? What is the origin of mass? Are there new dimensions? Can we produce black holes in the lab?

    Elementary particle physics is entering a spectacular new era in which experiments at the Large Hadron Collider at CERN will soon shed light on such questions and lead to a new deeper theory of particle physics, replacing the Standard Model proposed forty years ago. The two leading candidates for new theories are the Supersymmetric Standard Model and theories with Large Extra Dimensions, both proposed by Professor Dimopoulos and collaborators.

    Professor Dimopoulos is collaborating on a number of experiments that use the dramatic advances in atom interferometry to do fundamental physics. These include testing Einstein’s theory of general relativity to fifteen decimal precision, atom neutrality to thirty decimals, and looking for modifications of quantum mechanics. He is also designing an atom-interferometric gravity-wave detector that will allow us to look at the universe with gravity waves instead of light, marking the dawn of gravity wave astronomy and cosmology.

  • José R. Dinneny

    José R. Dinneny

    Professor of Biology

    Current Research and Scholarly InterestsThe biology of root systems is governed by both micro-scale and systemic signaling that allows the plant to integrate these complex variables into growth and branching decisions that ultimately determine the efficiency resources are captured. Research in my lab is aimed at understanding the response of roots to water-limiting conditions and is exploring this process at different organizational scales from the individual cell type to the level of the whole plant.

  • Rodolfo Dirzo

    Rodolfo Dirzo

    Associate Dean for Integrative Initiatives in Environmental Justice, Bing Prof in Environmental Science, Professor of Earth System Science and Senior Fellow at the Woods Institute for the Environment

    Current Research and Scholarly InterestsEcological and evolutionary aspects of plant-animal interactions, largely but not exclusively, in tropical forest ecosystems.
    Conservation biology in tropical ecosystems.
    Studies on biodiversity.
    Education, at all levels, on scientific practice, ecology and biodiversity conservation.

  • Scott Dixon

    Scott Dixon

    Associate Professor of Biology

    Current Research and Scholarly InterestsMy lab is interested in the relationship between cell death and metabolism. Using techniques drawn from many disciplines my laboratory is investigating how perturbation of intracellular metabolic networks can result in novel forms of cell death, such as ferroptosis. We are interested in applying this knowledge to find new ways to treat diseases characterized by insufficient (e.g. cancer) or excessive (e.g. neurodegeneration) cell death.

  • Sebastian Doniach

    Sebastian Doniach

    Professor of Applied Physics and of Physics, Emeritus

    Current Research and Scholarly InterestsStudy of changes in conformation of proteins and RNA using x-ray scattering

  • David Donoho

    David Donoho

    Anne T. and Robert M. Bass Professor in the School of Humanities and Sciences

    BioDavid Donoho is a mathematician who has made fundamental contributions to theoretical and computational statistics, as well as to signal processing and harmonic analysis. His algorithms have contributed significantly to our understanding of the maximum entropy principle, of the structure of robust procedures, and of sparse data description.

    Research Statement:
    My theoretical research interests have focused on the mathematics of statistical inference and on theoretical questions arising in applying harmonic analysis to various applied problems. My applied research interests have ranged from data visualization to various problems in scientific signal processing, image processing, and inverse problems.

  • Persis Drell

    Persis Drell

    Provost, Emerita, James and Anna Marie Spilker Professor, Professor of Materials Science and Engineering and of Physics

    BioPersis Drell is the James and Anna Marie Spilker Professor in the School of Engineering, a professor of materials science and engineering, and a professor of physics. From Feb 1, 2017 to Sept. 30, 2023, Drell was the provost of Stanford University.

    Prior to her appointment as provost in February 2017, she was dean of the Stanford School of Engineering from 2014 to 2017 and director of U.S. Department of Energy SLAC National Acceleratory Laboratory from 2007 to 2012.

    She earned her bachelor’s degree in mathematics and physics from Wellesley College and her PhD in atomic physics from UC Berkeley. Before joining the faculty at Stanford in 2002, she was a faculty member in the physics department at Cornell University for 14 years.

  • Justin Du Bois

    Justin Du Bois

    Henry Dreyfus Professor of Chemistry and Professor, by courtesy, of Chemical and Systems Biology

    BioResearch and Scholarship

    Research in the Du Bois laboratory spans reaction methods development, natural product synthesis, and chemical biology, and draws on expertise in molecular design, molecular recognition, and physical organic chemistry. An outstanding goal of our program has been to develop C–H bond functionalization processes as general methods for organic chemistry, and to demonstrate how such tools can impact the logic of chemical synthesis. A second area of interest focuses on the role of ion channels in electrical conduction and the specific involvement of channel subtypes in the sensation of pain. This work is enabled in part through the advent of small molecule modulators of channel function.

    The Du Bois group has described new tactics for the selective conversion of saturated C–H to C–N and C–O bonds. These methods have general utility in synthesis, making possible the single-step incorporation of nitrogen and oxygen functional groups and thus simplifying the process of assembling complex molecules. To date, lab members have employed these versatile oxidation technologies to prepare natural products that include manzacidin A and C, agelastatin, tetrodotoxin, and saxitoxin. Detailed mechanistic studies of metal-catalyzed C–H functionalization reactions are performed in parallel with process development and chemical synthesis. These efforts ultimately give way to advances in catalyst design. A long-standing goal of this program is to identify robust catalyst systems that afford absolute control of reaction selectivity.

    In a second program area, the Du Bois group is exploring voltage-gated ion channel structure and function using the tools of chemistry in combination with those of molecular biology, electrophysiology, microscopy and mass spectrometry. Much of this work has focused on studies of eukaryotic Na and Cl ion channels. The Du Bois lab is interested in understanding the biochemical mechanisms that underlie channel subtype regulation and how such processes may be altered following nerve injury. Small molecule toxins serve as lead compounds for the design of isoform-selective channel modulators, affinity reagents, and fluorescence imaging probes. Access to toxins and modified forms thereof (including saxitoxin, gonyautoxin, batrachotoxin, and veratridine) through de novo synthesis drives studies to elucidate toxin-receptor interactions and to develop new pharmacologic tools to study ion channel function in primary cells and murine pain models.

  • John Duchi

    John Duchi

    Associate Professor of Statistics, of Electrical Engineering and, by courtesy, of Computer Science

    Current Research and Scholarly InterestsMy work spans statistical learning, optimization, information theory, and computation, with a few driving goals: 1. To discover statistical learning procedures that optimally trade between real-world resources while maintaining statistical efficiency. 2. To build efficient large-scale optimization methods that move beyond bespoke solutions to methods that robustly work. 3. To develop tools to assess and guarantee the validity of---and confidence we should have in---machine-learned systems.

  • Bradley Efron

    Bradley Efron

    Max H. Stein Professor and Professor of Statistics and of Biomedical Data Science, Emeritus

    Current Research and Scholarly InterestsResearch Interests:
    BOOTSTRAP
    BIOSTATISTICS
    BAYESIAN STATISTICS

  • Paul Ehrlich

    Paul Ehrlich

    Bing Professor of Population Studies, Emeritus

    Current Research and Scholarly InterestsThe role of the social sciences in dealing with global change

  • Barbara Elizabeth Engelhardt

    Barbara Elizabeth Engelhardt

    Professor (Research) of Biomedical Data Science and, by courtesy, of Statistics

    BioBarbara E Engelhardt is a Senior Investigator at Gladstone Institutes and Professor at Stanford University in the Department of Biomedical Data Science. She received her B.S. (Symbolic Systems) and M.S. (Computer Science) from Stanford University and her PhD from UC Berkeley (EECS) advised my Prof. Michael I Jordan. She was a postdoctoral fellow with Prof. Matthew Stephens at the University of Chicago. She was an Assistant Professor at Duke University from 2011-2014, and an Assistant, Associate, and then Full Professor at Princeton University in Computer Science from 2014-2022. She has worked at Jet Propulsion Labs, Google Research, 23andMe, and Genomics plc. In her career, she received an NSF GRFP, the Google Anita Borg Scholarship, the SMBE Walter M. Fitch Prize (2004), a Sloan Faculty Fellowship, an NSF CAREER, and the ISCB Overton Prize (2021). Her research is focused on developing and applying models for structured biomedical data that capture patterns in the data, predict results of interventions to the system, assist with decision-making support, and prioritize experiments for design and engineering of biological systems.

  • Shanhui Fan

    Shanhui Fan

    Joseph and Hon Mai Goodman Professor of the School of Engineering and Professor, by courtesy, of Applied Physics

    BioFan's research interests are in fundamental studies of nanophotonic structures, especially photonic crystals and meta-materials, and applications of these structures in energy and information technology applications

  • Michael Fayer

    Michael Fayer

    David Mulvane Ehrsam and Edward Curtis Franklin Professor of Chemistry

    BioMy research group studies complex molecular systems by using ultrafast multi-dimensional infrared and non-linear UV/Vis methods. A basic theme is to understand the role of mesoscopic structure on the properties of molecular systems. Many systems have structure on length scales large compare to molecules but small compared to macroscopic dimensions. The mesoscopic structures occur on distance scales of a few nanometers to a few tens of nanometers. The properties of systems, such as water in nanoscopic environments, room temperature ionic liquids, functionalized surfaces, liquid crystals, metal organic frameworks, water and other liquids in nanoporous silica, polyelectrolyte fuel cell membranes, vesicles, and micelles depend on molecular level dynamics and intermolecular interactions. Our ultrafast measurements provide direct observables for understanding the relationships among dynamics, structure, and intermolecular interactions.

    Bulk properties are frequently a very poor guide to understanding the molecular level details that determine the nature of a chemical process and its dynamics. Because molecules are small, molecular motions are inherently very fast. Recent advances in methodology developed in our labs make it possible for us to observe important processes as they occur. These measurements act like stop-action photography. To focus on a particular aspect of a time evolving system, we employ sequences of ultrashort pulses of light as the basis for non-linear methods such as ultrafast infrared two dimensional vibrational echoes, optical Kerr effect methods, and ultrafast IR transient absorption experiments.

    We are using ultrafast 2D IR vibrational echo spectroscopy and other multi-dimensional IR methods, which we have pioneered, to study dynamics of molecular complexes, water confined on nm lengths scales with a variety of topographies, molecules bound to surfaces, ionic liquids, and materials such as metal organic frameworks and porous silica. We can probe the dynamic structures these systems. The methods are somewhat akin to multidimensional NMR, but they probe molecular structural evolution in real time on the relevant fast time scales, eight to ten orders of magnitude faster than NMR. We are obtaining direct information on how nanoscopic confinement of water changes its properties, a topic of great importance in chemistry, biology, geology, and materials. For the first time, we are observing the motions of molecular bound to surfaces. In biological membranes, we are using the vibrational echo methods to study dynamics and the relationship among dynamics, structure, and function. We are also developing and applying theory to these problems frequently in collaboration with top theoreticians.

    We are studying dynamics in complex liquids, in particular room temperature ionic liquids, liquid crystals, supercooled liquids, as well as in influence of small quantities of water on liquid dynamics. Using ultrafast optical heterodyne detected optical Kerr effect methods, we can follow processes from tens of femtoseconds to ten microseconds. Our ability to look over such a wide range of time scales is unprecedented. The change in molecular dynamics when a system undergoes a phase change is of fundamental and practical importance. We are developing detailed theory as the companion to the experiments.

    We are studying photo-induced proton transfer in nanoscopic water environments such as polyelectrolyte fuel cell membranes, using ultrafast UV/Vis fluorescence and multidimensional IR measurements to understand the proton transfer and other processes and how they are influenced by nanoscopic confinement. We want to understand the role of the solvent and the systems topology on proton transfer dynamics.

  • Benjamin Ezekiel Feldman

    Benjamin Ezekiel Feldman

    Assistant Professor of Physics

    Current Research and Scholarly InterestsHow do material properties change as a result of interactions among electrons, and what is the nature of the new phases that result? What novel physical phenomena and functionality (e.g., symmetry breaking or topological excitations) can be realized by combining materials and device elements to produce emergent behavior? How can we leverage nontraditional measurement techniques to gain new insight into quantum materials? These are some of the overarching questions we seek to address in our research.

    We are interested in a variety of quantum systems, especially those composed of two-dimensional flakes and heterostructures. This class of materials has been shown to exhibit an incredible variability in their properties, with the further benefit that they are highly tunable through gating and applied fields.