Melissa Ann Hines - US grants

This Faculty Early Career Development (CAREER) project, supported in the Analytical and Surface Chemistry Program, focuses on the detailed microscopic, macroscopic, and computational characterization of etched silicon surfaces. In particular, the use of a new class of aqueous, fluorine-based etchants will be investigated. Professor Hines and her students at Cornell University will employ scanning tunneling microscopy to study the physical structure (quality) of the resultant etch patterns while etch rate measurements will give evidence of the kinetics of the process. Monte Carlo calculations will be incorporated to help simulate the observed chemistry. This CAREER project will improve the computational skills of undergraduates and graduates through the implementation of a `Numerical Analysis for Chemists` course. Professor Hines will also improve students' readiness for the workforce through seminars in writing and public speaking skills. The study and development of new chemistries which can be applied to semiconductor processing systems continues to be a very vibrant area of research. Professor Hines and her students at Cornell University are combining physical measurement techniques and computational simulations to evaluate the use of a new family of aqueous, fluorine-based etchants. Previous studies have suggested that atomically flat silicon surfaces could be produced by these methods. This CAREER project holds the promise of producing results of substantial technological importance. Professor Hines will enhance the development of scientists with skills in the important area of computational chemistry through the introduction of a new undergraduate/graduate student course in that area. Technical writing and public speaking skills will be developed through topical seminars and coursework.

Cornell University operates a Research Experience for Undergraduates (REU) Site affiliated with its NSF-funded Materials Research Science and Engineering Center. The REU Site offers research opportunities for undergraduate students in a wide variety of materials-related topics; the understanding and control of materials in the nanoscale is the common thread of the research programs. Twenty undergraduate students are recruited every year for a ten-week summer research experience. The REU Site actively promotes the participation of women and students from underrepresented groups and from predominantly undergraduate institutions.
In addition to participating in individual research projects, students attend weekly technical seminars and career workshops, and participate in collective social activities.

Through participation in the summer activities, students in the program are afforded a wider perspective on research than they might see as part of their regular undergraduate studies. This familiarity with different perspectives on scientific research helps them to understand the many different pathways leading to a career in science and engineering research.

This award from the Instrumentation for Materials Research program supports the acquisition of a Digital Instruments Dimension 3100 Scanned Probe Microscope (SPM) System with a NanoScope IV Controller. This instrument will be placed in a central facility to be employed in the research of dozens of undergraduate and graduate students from many departments at Cornell. It will also be used by Cornell nanotechnology classes, K-12 tours, and outside users. The microscope will enable new research directions dealing with nanoscale electrical devices, nanoscale chemical modification, polymer dynamics near surfaces, the development of new types of scanning microscopy, and biomaterials characterization. It will take the place of an older SPM that will be relocated to Simmons College, a women's college in Boston, to be used in undergraduate research aimed at developing polymer materials for organic light-emitting diodes.
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This award from the Instrumentation for Materials Research program supports the acquisition of a Digital Instruments Dimension 3100 Scanned Probe Microscope (SPM) System, which will be placed in a central facility for use by dozens of undergraduate and graduate students in projects that require imaging samples with nanometer-scale resolution. For example, it will be used to examine molecular-scale electronic devices while they are in operation, the atom-by-atom processes by which chemicals can sculpt surfaces, and the self-assembly of biological materials. The microscope will also be employed by Cornell nanotechnology classes, visiting high-school teachers and students, and outside users. It will take the place of an older scanned-probe microscope that will be relocated to Simmons College, a women's college in Boston, Massachusetts. This will provide students at Simmons and nearby colleges the opportunity to work with a research-quality instrument as they are encouraged to consider technical careers.

This research project, supported in the Analytical and Surface Chemistry Program, addresses the mechanism of etching of silicon surfaces. Using a combination of scanning probe microscopy and kinetic Monte Carlo simulation methods, Professor Hines and her colleagues in the Department of Chemistry at Cornell University are investigating the effect of etching conditions on the silicon surface morphology. Experiments are addressing the aqueous etching of the Si(111) surface by KOH solution, as well as the anodic etching of silicon surfaces used to create porous silicon materials. The effects of step orientation, step density, and silicon dopant, as well as etchant composition and concentration are being examined. Results of this work are important for the design of nanomaterial technologies, as well as for the development of electronic materials processing strategies.

Information about how chemical etchants remove material from the surface of a silicon wafer is important for the design of processes to make micro-electromechanical (MEMS) devices, and for the production of electronic and photonic devices. The work of this research project is directed to developing an understanding of the aqueous and electrochemical etching of silicon, with the goal of developing a microscopic understanding of what controls the atomic and nano-scale morphology of the etched surface. With the support of the Analytical and Surface Chemistry Program, Professor Hines and her colleagues at Cornell, are using a combination of microscopy and computer simulation to obtain this information.

This grant provides support for the acquisition of instrumentation for low temperature research and education on micro/nano-scale electromechanical resonators at Cornell University. This critical instrumentation will enable low temperature actuation and detection of ultra-small, high frequency resonant structures. Nanoscale mechanical structures have the potential to enable new functionalities and ultra sensitive sensor technology by taking advantage of their low mass. New designs that optimize devices are one of the foci of the research that will be enabled by this instrument. Access to low temperatures where intrinsic loss mechanisms are quenched should lead to a significant increase in the quality factor, a basis of new high-sensitivity devices. The new instrumentation will also enable parametric amplification at low temperatures via electromagnetic, optical, or other methods. The enhanced quality factor is critical in helping to expose non-intrinsic design and process dependent losses. The optimization of the low temperature properties of these structures will positively impact applicability, improve room temperature behavior, and provide significant educational opportunities.

The simultaneous exploration of these frontiers will present exciting research opportunities for graduate students and post-doctoral associates and will be a valuable introduction to nano-technology for undergraduates as well as high school teachers. The intuitive appeal of these ultra-small devices will attract students into the sciences at an early stage. Access to these diverse audiences is planned under our program. The instrument itself will be a challenge to complete, and will provide an outstanding training ground for researchers at all levels in the fundamental sciences, and advanced nano-technology that is vital to our future technological infrastructure.

Abstract
CHE-0515436
Hines/Cornell

Professor Hines and her coworkers in the Department of Chemistry at Cornell University are examining the fundamental mechanisms that control surface morphology of silicon during aqueous etching processes. With the support of the Analytical and Surface Chemistry Program, this group is using scanning probe microscopy coupled with kinetic Monte Carlo methods to study the surface morphology during the wet etching of silicon surfaces. They are focusing on the chemical factors that lead to specific morphologies, and are working to develop an etchant capable of producing atomically flat Si(100) surfaces. A fundamental understanding of the silicon wet etching process would strongly impact the commercial production of electronic devices. Students trained in this area will make important contributions to the semiconductor industry.

A fundamental understanding of the evolution of surface morphology during the wet chemical etching of silicon surfaces is the goal of this research project. Professor Hines and her group are using scanning probe microscopy and model calculations to examine the chemical effects of etchants on the morphology of the processed silicon surface. Information from this research is important for the development of efficient, directed processes in the semiconductor industry.

The major theme of the MRSEC research and education programs at the Cornell Center for Materials Research (CCMR) is Mastery of Materials at the Atomic and Molecular Level. The objective is to educate scientists and engineering students (largely PhD students) and postdoctoral researchers in the methods of research used to tackle cutting edge problems in materials research. At the same time CCMR manages and maintains a set of shared experimental facilities that enable this research to be carried out; these facilities are also actively used by a wide spectrum of researchers from across the campus, from other Universities, Government Laboratories and Industry. CCMR also has an expansive and effective educational outreach program that helps students and teachers from primary, secondary and local colleges to learn about materials sciences, recent advances and how to integrate this new knowledge into the classroom. Finally, CCMR's Industrial Partnerships program speeds the transition of new scientific discoveries into technologies that can promote economic growth and opportunities.

Our research is organized into teams focused on several specific topics, including: Controlling Electrons at Interfaces, "Building Blocks" for Photonic Systems, and the Study of the Dynamics of Growth of Complex Materials. CCMR also manages a "Seed Program" that supports smaller short term activities that explore high-risk/high-payoff areas and that integrates new faculty into our interdisciplinary culture. Our long term goal is to control materials systems at or near the level of atomistic precision (atom identity and geometric placement), as is possible in the synthesis of some organic molecules. Our vision is that such control will allow precision tuning of properties and is likely to uncover vast new areas of science, to facilitate the construction of a wide variety of novel devices, and to enable technologies not presently imagined. The proposed research capitalizes on unique science we recently developed, substantially extends the effort in new and ground breaking directions, and explores entirely new topics; all require new talents, new skills and new senior investigators.

This Integrative Graduate Education and Research Traineeship (IGERT) award supports a graduate training program at Cornell University in a highly interdisciplinary area of materials research that is central to advances in many areas of science and technology - the nanoscale control of surfaces and interfaces. This program provides doctoral students drawn from seven academic disciplines with hands-on, interdisciplinary training in the experimental and theoretical techniques necessary for forefront research at the nanoscale. The program is based on a dynamic, student-centric educational framework that transitions students from the coursework-based educational model typical of K-16 education to the self-directed learning necessary for professional R&D environments. As an integral part of their training, students perform interdisciplinary research on topics as diverse as the production of single molecule transistors, the design of non-volatile memory, the development of "plastic" electronics, and the fabrication of ultrasensitive chemical and biological sensors.
This program addresses the national workforce needs in materials research documented by a recent National Academies study. The study identified the field of nanomaterials - the focus of this traineeship - as the area of most rapid growth globally. By educating a new generation of nanomaterials researchers and performing fundamental research in this rapidly growing area, this program increases U.S. competitiveness. The program also addresses the underrepresentation of women and minorities in the field of materials through direct partnerships with two Historically Black Colleges/Universities, a substantial recruiting program and an extensive undergraduate research program. IGERT is an NSF-wide program intended to meet the challenges of educating U.S. Ph.D. scientists and engineers with the interdisciplinary background, deep knowledge in a chosen discipline, and the technical, professional, and personal skills needed for the career demands of the future. The program is intended to catalyze a cultural change in graduate education by establishing innovative new models for graduate education and training in a fertile environment for collaborative research that transcends traditional disciplinary boundaries.

The Analytical and Surface Chemistry (ASC) program of the Division of Chemistry supports the research project of Prof. Melissa Hines of the Department of Chemistry at Cornell University. Prof. Hines and her students will build upon their recent discovery of an anisotropic etchant that produces Si(100)surfaces with near-atomically flat morphologies and continue to develop new reactions and processes that enable the chemical control of surface morphology. They will study chemically etched Si(100) surfaces and the fundamental chemical mechanisms that control the evolution of Si(100) surface morphology during aqueous silicon etching using a combination of infrared absorption spectroscopy, scanning tunneling microscopy, and kinetic Monte Carlo simulations. The study will provide excellent training opportunities to graduate and undergraduate students in a cutting edge research field with direct relevance to high end applications in the semiconductor industry.

The Effect of Surfaces on the Strength of Nanoscale Structures

This collaboration between an engineering and a chemistry laboratory will develop an understanding of fracture at the atomic scale using a newly developed technique capable of accurately measuring the strength of tiny (nanoscale) samples of material. Previous research by the collaborators has shown that a single layer of molecules can significantly improve the strength of nanoscale silicon beams, whereas atomic-scale roughness can lead to strength degradation. A combination of experiments and computer simulations will be used to understand the origins of these effects. This understanding will enable the development of chemical coatings and processes for the production of very strong and very stable nanometer-scale mechanical devices.
By integrating research and education, this interdisciplinary project will educate undergraduate and graduate students in an area of increasing technological and economic importance the production of high strength, long-life micro- and nano-electromechanical devices (MEMS and NEMS) and will prepare these students for subsequent careers in education, industry and public service. The project will contribute to the advancement of technology by developing new commercially-viable processes. To attract more students to careers in science and technology, particularly students from traditionally underrepresented groups, members of the research team will participate in a variety of educational outreach activities to K-12 students and teachers. In addition to new activities, the researchers will continue their involvement with the Cornell Institute for Chemistry Teachers and Project High Jump two programs designed to improve high school education.

The Center of Excellence in Materials Research and Innovation* (CEMRI) at the Cornell Center for Materials Research (CCMR) will explore fundamental challenges in interdisciplinary materials research that will enable technological progress of a scope and complexity that requires the sustained contribution of researchers from multiple disciplines. In doing so, the Center will develop the experimental and theoretical tools and techniques necessary for further advances.

Research in the Center will be pursued through three Interdisciplinary Research Groups (IRGs) as well as a number of smaller Seed research projects. The theme of IRG-1 is to understand and control complex electronic materials that have spectacular electronic and magnetic properties, including high temperature superconductivity, huge electric field effects, and many forms of nanoscale electron self-organization. Starting from materials that are reasonably well described by existing theory, the group will systematically perturb the targeted materials through experimentally-accessible parameters such as electron overlap and carrier density, using observed changes in materials properties to drive new advances in understanding. The goal of IRG-2 is to understand and apply new mechanisms to manipulate electron spins in both ferromagnetic and non-ferromagnetic materials. This research will potentially enable nonvolatile magnetic memory technologies that are much smaller, more energy efficient, more reliable, faster, and less expensive than competing strategies, possibly leading to the replacement of silicon-based memories in many applications. IRG-3 will explore atomic membranes an exciting new class of two-dimensional, free-standing materials only one atom thick yet mechanically robust, chemically stable, and virtually impermeable. Applications for these membranes loom in almost every technological sector from electronics to chemical passivation to high-resolution imaging, but major materials challenges must first be addressed. The timely exploration of novel ideas, higher-risk and potentially transformative projects will be enabled by a Seed research program that will pursue limited-term, exploratory research projects. This program will nucleate new interdisciplinary, materials-focused research projects, integrate new faculty into the Center, and refresh the Center's portfolio of research. National and international collaborations will augment and enable the Center's research by providing access to one-of-a-kind facilities, specialized instrumentation, new techniques, and world-leading expertise.

The research program will educate a diverse cadre of undergraduates, graduate students, and postdoctoral scholars in areas of national need and importance. To further improve the national supply of science and engineering students, Center researchers will partner with K-12 teachers to improve student interest and achievement in science, technology, and mathematics. These activities will be complemented by a summer research program that will provide undergraduate students with an introduction to materials research. The Center will enhance the local and national materials research infrastructure by offering both routine and state-of-the-art Shared Facilities, offering fabrication, analysis, and characterization and consultation to all users (on a fee-per-use basis). Knowledge transfer to industry and other sectors will be stimulated by extensive collaborations with international, industrial, academic, and national lab researchers, as well as by a multifaceted industrial partnerships program.

* An NSF Materials Research Science and Engineering Center (MRSEC)

In this project, funded by the Macromolecular, Supramolecular and Nanochemistry Program of the Chemistry Division, Prof. Melissa A. Hines of Cornell University and her students will use solution-based chemical reactions and surface science techniques to create, understand, and control the performance of high-reactivity titanium dioxide surfaces in technologically relevant environments, including air and solution. This project will develop solution-based chemical techniques for producing well-controlled anatase surfaces in a laboratory environment, for removing growth-directing agents from the surfaces, and for preparing clean, reproducible anatase surfaces suitable for surface-science-based studies of chemical and photochemical reactivity. By correlating the atomic-scale structure of the grown surfaces with the amount of shape-controlling chemicals in the growth solution or the amount of surface-removing chemicals in the etching solution, researchers will obtain quantitative understanding of the surface-site-specific chemical reactions that control the growth and chemical structure of anatase surfaces. The knowledge and techniques garnered from this study will provide new understanding of anatase surfaces under technologically relevant conditions, will lead to the development of new chemical reactions for the production of high-reactivity anatase surfaces and nanocrystals, and will produce a platform for further surface-science studies of anatase reactivity.

This study will enable the rational improvement of nanoscale surfaces necessary for emerging sustainable technologies. The project will develop the substrates, the expertise, and the processing protocols necessary for understanding and controlling the performance of high-reactivity surfaces under technologically relevant conditions, including air and solution. By integrating research and education, this project will train postdoctoral, graduate, and undergraduate students in areas of national need. The project is expected to increase student interest and achievement in science, technology, engineering, and mathematics (STEM fields) through a variety of activities targeting K-12 students and their teachers. Particular attention will be placed on increasing the involvement of historically underrepresented groups, such as women and racial and ethnic minorities.

Nontechnical: This award supports the acquisition of a first-of-its-kind electron microscope that allows materials to be studied in their natural environment using an electron beam that can be focused down to a subatomic spot, producing three-dimensional images of their structure and chemistry. While traditional electron microscope studies are limited to only materials that can survive in a hard vacuum comparable to that of outer space, this new instrument will, for the first time, allow researchers to take snapshots of both solids and liquids, and more importantly see the processes that occur at interfaces between solids and liquids stabilized by snap freezing. Understanding such interfaces has a wide-ranging impact, from enabling scientists and engineers to design more durable batteries, more efficient catalysts for automotive fuel cells, to better retain nutrients in soil. To meet the huge demand for this capability both across campus, and also from industries and universities across the country, this instrument will be available as part of Cornell Center for Materials Research (CCMR) to researchers and students across campus as well as from other universities, industry and national labs. The microscope will also provide hands-on research opportunities for undergraduates, particularly under-represented minorities and women as part of the CCMR Research Experience for Undergraduates program, offer middle school girls the opportunity to experience the excitement of science as part of the Expanding Your Horizons program, and support K-12 teachers development through CCMR's Research Experience for Teachers program, and through MicroWorld, a microscopy-based activity that will be adapted to meet the challenges of the Next Generation Science Standards. This instrument will have broad impacts on science research and training by providing unique characterization capabilities of materials and devices and by educating a new generation of electron microscopists, which will lead to major scientific and technical advances in broad areas of research that are critical to the fulfillment of the nation?s research agenda, and the maintenance of the country's competitive position in critically important fields of science and technology.


Technical: Recent advances in electron microscopy design have opened a new era of atomic resolution imaging and spectroscopy inside solids. Liquid/solid interfaces have yet to be imaged at high spatial resolution, but play a critical role in a range of biological, chemical and physical processes from catalysis to electrochemical energy storage to the formation of biominerals. With the ability to study liquids snap-frozen in a vitreous state, this cryo-STEM, combining the low-vibration cryo-stages from biology with the resolution-enhancing aberration-correctors from materials science, will enable presently unfeasible structural and spectroscopic studies of electrode/electrolyte interfaces in batteries and fuel cells, organic/mineral interfaces in breast cancer tumors and calcified aortic valves, and liquid/mineral complexes in soils. More generally, this class of "hard/soft" interfaces between minerals and liquids or soft tissue has not been explored at high spatial resolution, as the methods for studying the "hard" and "soft" components have been incompatible. Operating at cryogenic temperatures will also allow users to gain unprecedented insights into the macromolecular organization of cellular environments at nanometer resolution and to access a new range of emergent electronic states and phases in artificially engineered materials and strongly-correlated systems. With the ability to capture the early stages of nucleation at interfaces, long unanswered questions in fields across multiple disciplines from biomineralization to energy conversion and storage, complex electronic materials and carbon sequestration using soils can be addressed.

Nontechnical Abstract: The Cornell Center for Materials Research (CCMR), a Materials Research Science and Engineering Center, is enhancing national capabilities in science, technology, engineering, and mathematics fields and materials research at all levels through an integrated research and education program. The central mission of the Center is to explore and advance the design, control, and fundamental understanding of materials through collaborative experimental and theoretical studies. The Center focuses on forefront scientific challenges of a scope and complexity requiring the combined expertise of interdisciplinary teams of researchers and collaborators. In doing so, the Center is developing the underlying science needed, for example, to advance next-generation computer memories, to enable information processing with light, and to realize a new class of self-folding devices based on atomically-thin, paper-like materials. Through these research activities, the Center is educating a diverse cadre of undergraduates, graduate students, and postdoctoral scholars to become leaders in the field of materials research at industrial, academic, and government organizations, while also developing pedagogical materials for K-12 classrooms that excite and inspire the next generation of scientists and engineers. The CCMR Shared Facilities enable frontier research while enhancing the nation's infrastructure for advanced research and development.

Technical Abstract: The goal of the Mechanisms, Materials, and Devices for Spin Manipulation IRG is to discover, understand, and apply new mechanisms for controlling spins in magnetic devices. The Interdisciplinary Research Groups (IRG's) research aims to provide the scientific foundations for energy-efficient nonvolatile memories with revolutionary capabilities as well as frequency-agile nanoscale microwave sources and signal-processing devices. The goal of the Structured Materials for Strong Light-Matter Interactions IRG is to understand, create, and harness exceptionally strong and unconventional light-matter interactions for scientific discoveries and future photonic information processing technology. The IRG aims to enhance the nonlinear effects that enable photon-photon and photon-matter interactions and to efficiently create and control the emission of high-quality single photons for quantum optical technology. The IRG is designing, fabricating, and testing "structured materials:" high-performance optical materials that are sculpted on the nano- or mesoscale to enhance their optical properties, enabling stronger photon-photon and photon-material interactions. The goal of the 2D Atomic Membranes for 3D Systems IRG is to explore the fundamental challenges associated with transducing small local signals into global observable changes at nanoscale dimensions in a targeted design structure. To do this, the group is combining recent advances in two-dimensional atomic membranes growth with the scale-invariant properties of the centuries-old art forms of origami ("ori" = fold) and kirigami ("kiri" = cut). Their aim is to take miniaturization to its ultimate limit, creating atomically thin "paper" materials that self-fold into incredibly responsive structures with lateral features at the micron to nanometer scale. Through a series of integrated educational activities, the CCMR is impacting K-12 teachers and students; undergraduate, graduate and postdoctoral scholars; and faculty.

Titanium dioxide (TiO2) is an inexpensive crystalline material that has long been used as white coloring in applications ranging from paint to powdered doughnuts. When the titanium dioxide particle size is on the order of 0.00000005 inches, TiO2 exhibits enhanced catalytic activity, a chemical phenomenon in which the TiO2 increases the efficiency and selectivity of chemical processes by providing alternative reaction pathways. In recent years, the low cost and non-toxic properties of titanium dioxide nanocatalysts have led to their commercialization for solar water purification in third-world countries, for flexible solar cells fabricated by roll-to-roll printing, and for self-cleaning building materials. While chemists have long known that the reactivity of these nanocrystals depends critically on their shape and structure, there is little fundamental understanding of these dependencies and thus no rational means for improving their performance. In this research project, Prof. Melissa Hines and her graduate students at Cornell University are using atomic-scale microscopy to study the structure and reactivity of a variety of small molecules during their interaction with titanium dioxide surfaces. Using insights gained from these experiments, she and her students are developing new methods to improve the performance of these crystals, including the growth of surface-supported, nanoscale networks. The fundamental understanding gained from these experiments will help future applications, such as new types of batteries or solar cells with improved performance. To share their enthusiasm about science with school children, she and her group are developing hands-on science lessons for middle school students, visiting schools to perform these experiments, and contributing these lessons to an online lending library of science experiments for teachers nationwide.

In this project, funded by the Macromolecular, Supramolecular, and Nanochemistry (MSN) Program of the Chemistry Division, Prof. Melissa A. Hines of Cornell University and her students are using solution-based chemical reactions and surface science techniques to produce the fundamental understanding necessary for the development of sustainable, non-toxic, earth-abundant nanocatalysts, photocatalysts, photovoltaic devices, and energy-storage materials. The research uses solution-deposited, self-assembled monolayers of molecular exemplars to study the atomic-scale structure of seven of the most commonly used organic linkages to metal oxide surfaces. These monolayers are deposited on the surfaces of well-controlled rutile (110) single crystals and epitaxial anatase (001) films and studied with a combination of experimental and computational techniques, including scanning tunneling microscopy, infrared and x-ray photoemission spectroscopies, and first-principles modeling. This research is producing the understanding necessary for the rational development of high strength and/or high conductivity organic coatings on metal oxide nanocatalysts and thin films, while also developing the high quality self-assembled monolayers necessary for electronic characterization of molecule-titanium dioxide linkages. The organic linkage chemistries are being explored for use in a new class of surface-supported, highly porous, conducting nanoscale networks. Coupled with this research, Hines and her group are developing new hands-on science experiments that are aligned with the Next Generation Science Standards and suitable for the middle school classroom. The group field tests these activities in K-12 classrooms and through teacher development programs. The finished experiments are made available to any teacher in the nation through an online lending library.

With the support of the Macromolecular, Supramolecular, and Nanochemistry Program in the Division of Chemistry, Dr. Melissa Hines of Cornell University will investigate the reactivity and photoreactivity of fluorinated and fluorine-doped titanium dioxide using scanning tunneling microscopy, x-ray photoelectron spectroscopy, and density functional theory. The resulting atomic-scale understanding of these surfaces is expected to contribute to the development of sustainable, non-toxic, earth-abundant nanocatalysts and photocatalysts. Dr. Hines and the research team are advancing discovery in nanocatalysis, sustainable chemistry, and surface science. This research is also training the next generation of scientists in a field that is important to maintaining US economic competitiveness. To increase the number and diversity of students entering science and technology fields, they are developing modules for middle school students that focus on quantitative measurements and scientific experiments that engage both students and faculty.

This research involves the development of chemical reactions and an ultraclean reactor to study the solution-phase chemistry and photochemistry of fluorinated titanium dioxide. This includes the determination of the primary mechanisms that lead to fluorine-functionalized titanium dioxide surfaces and the role of photogenerated charge carriers in these mechanisms, identification of new fluorination agents for preparing atomically flat fluorinated titanium dioxide surfaces, and assessment of the impact of fluorination on the photoreactivity of titanium dioxide. This research will also address the photo-fluorination of organic acids in aqueous solution. Developing an atomic-scale understanding of these surfaces and their reactivity has the potential to enable the production of passivated, contamination-resistant metal oxide surfaces and high reactivity photofluorination catalysts that operate under more environmentally friendly conditions than current catalysts.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.