Mercouri G. Kanatzidis - US grants

This Presidential Young Investigator award from the Inorganic, Bioinorganic and Organometallic Chemistry Program will support the research of Dr. Mercouri Kanatzidis on the chemistry of sulfur and selenium compounds of heavy metals. One facet of the research program will focus on the chemistry of ruthenium/ sulfur compounds, with the aim of attaining new insights into heterogeneous catalytic processes such as the hydrodesulfurization of petroleum by ruthenium disulfide. The second facet of the research program involves research at the interface of inorganic chemistry and materials science. The techniques of synthetic inorganic chemistry will be used to produce precursors to new materials, such as low dimensional intermetallic alloys. Anionic soluble clusters containing late transition and main group metals bridged by either selenium or tellurium will be formed in solution and then precipitated with heavy metals such as cadmium to form new solid compounds. An example of a substance synthesized in this manner has the composition Cd:Hg:Te = 1:1:8, and has potential applications in the area of low energy detection. Also to be explored are syntheses of metal/sulfur and metal/selenium compounds at high temperatures with molten salts as solvents. Of particular interest are compounds containing S-S or Se-Se bonds which can be reductively (and reversibly) cleaved electrochemically or by reaction with alkali metals. Such materials may be useful as cathodes for high energy density rechargeable batteries.

The PI aims to intercalate conductive polymers into the intralamellar space of layered vanadium pentoxide xerogels. This is to be done by the in-situ oxidation intercalation of the monomers using the xerogel as the oxidant.

Molten polychalcogenide salt and hydrothermal techniques will be used to explore the synthesis of new chalcogenide materials at low and intermediate temperatures. Both synthetic techniques will use various A2Qx salts in reactions with late transition metals and main-group elements. Reactions at temperatures between 200-500 oC will be studied because this range has been little explored previously. It has been demonstrated that in this temperature range new materials with new structure types can form and crystallize. The remarkable ability of sulfur, selenium, and tellerium to bridge different sub-structures in two and three dimensions, and the relatively low temperatures provide a lucrative opportunity for synthesis of a very large number of new compounds. Physical properties of these new compounds to be explored include magnetic, sorption as a function of temperature, and redox properties. In order to probe unusual electronic phenomena, the charge transport properties of the new compounds will be studied in detail via variable temperature four-probe resistivity as well as thermoelectric power (Seebeck) measurements. The measurements will be primarily done on single crystal samples. This grant is jointly supported by the Division of Materials Research and Chemistry Division.

This award from the Chemistry Research Instrumentation Program will help the Department of Chemistry at Michigan State University to acquire Sparc II workstations and some ancillary equipment. The areas of chemical research that will be enhanced by the acquisition include: 1. Chemistry of Highly Reactive Mononuclear and Polynuclear Transition Metal Cations 2. The Study of the Molecular Basis of Procaryote/Eucaryote Interactions 3. Organic Ferromagnets and Odd-Electron Sigma Bonds 4. Chemistry of Soluble Metal Polychalcogenides %%% Chemists carrying out frontier research are relying more and more on computers that are capable of handling sophisticated simulations, data analysis and graphics software. The workstations which will be purchased with this grant are not only powerful and cost effective computers by themselves, but will serve also as communication links to allow transfer of data to and from other workstations and to provide access to remotely located more powerful computers.

9306385 Kanatzidis In the work, technologically significant conjugated and saturated polymers are intercalated into lamellar hosts. Studies on the (polymer) hydrated vanadium pentoxide and (polymer) iron oxychlorides will continue to better understand their structure and properties. Experiments to gain insights into the degree of polymerization of the conductive polymers in these materials are proposed. Based on the n-type to p-type transition which occurs as a function of x in (polymer) hydrated vanadium pentoxide, the behavior of p-n diodes will be studied. Single crystals of polyanaline/iron oxychloride will be explored by crystallographic analysis and charge transport measurements. In what constitutes a new research direction, new methodologies will be developed to include other layered hosts, which are not amenable to in-situ intercalative redox polymerization. A variety of new conjugated polymer/inorganic intercalation compounds will be prepared. These new hosts include uranyl phosphate, zirconium phosphates and phosphonates, molybnenum oxides and transition metal dichalcogenides. In addition to conjugated polymers, saturated polymers will be used to prepare novel molecular scale nano- composites with layered inorganic hosts. A full physico-chemical characterization of these materials is proposed. ***

9509249 Kanatzidis The proposed symposium is titled "Synthesis Reactivity and Properties of Non-Oxidic Solids". We chose this topic to highlight the significance of these materials to fundamental chemistry and to technology. Although the chemistry and significance of oxides is well known to the chemical community and well represented by a plethora of ACS and other symposia, in general non-oxides such as chalcogenides, halides, pnictides, borides, carbides and intermetallics have received very little attention, especially in ACS symposia. These materials impact both our understanding of fundamental chemical science and our technological progress in a major way. Little is known about these materials, and an ACS symposium will help in projecting the important issues and problems in this area to a broad chemistry audience and particularly to students and young researchers. The proposed symposium is very timely given the continuing strong interest in the properties of these compounds which include non- linear optics (chalcogenide, pnictides, superconductivity (borides), rechargeable batteries (hydrides), oxygen storage and transport (cyanides) and others. Emphasis will be given to new synthetic techniques, measurement and characterization and processing of non-oxidic solids. %%% To the best of our knowledge, this is the first symposium that focuses specifically on non-oxide solid state materials. ***

Abstract 9527347 Kanatzidis This research is concerned with the use of molten polychalcogenide salts as reactive media to explore the synthesis of new chalcogenide materials at low and intermediate temperatures (200-500 C). Various A2QX salts (A=alkali cation, Q=S, Se, Te) will be used in reactions with late transition metals and main-group elements. Emphasis will be given in the stabilization of quaternary phases. Three kinds of quaternary compounds will be explored in this stage. One kind involves the mixed-metal system A/M/M'/Q (M=late transition metal, M'=lanthanide, actinide). The second involves the mixed-chalcogen system A/M/S/Te. The synthetic approach will use binary alloy compounds as starting materials and mixed fluxes such as mixed A2TexSy. The third kind involves the use of the thio- and seleno-phosphate fluxes in materials synthesis. These fluxes are new and are designed to yield novel thiophosphate and selenophosphate solids containing the PxQy n- polyanions (where Q=S, Se). The physical properties of the new compounds, such as spectroscopic, thermal and magnetic will be studied as a function of temperature. In order to probe for unusual electronic phenomena, the charge transport properties of the new compounds will be studied in detail via variable temperature four-probe resistivity and thermoelectric power (Seebeck) measurements on single crystals. %%% This research is concerned with new methodologies to discover new solid state materials having various technologically important properties. Promising materials will be studied further and their potential for applications will be evaluated. The subject of this proposal is performing reactions using molten salts as solvents. Molten salts have been employed for well over 100 years for high- temperature single crystal growth. Although many salts are high melting species, eutectic combinations of binary salts and salts of polyatomic species often have melting points well below the te mperatures of classical solid-state synthesis, making possible their use in the exploration of new chemistry at intermediate temperatures. In some cases, such salts act not only as solvents, but also as reactants, providing species which can be incorporated into the final product. Such studies are important because polysulfide ligands have been implicated in the hydrodesulfurization of crude oil, where they are thought to be present at the surface of metal sulfide catalysts. Polychalcogenide glasses also are important as materials for non-linear optics, IR wave guides, optical switching, and optical information storage, but the structure/property relationships have not been well determined due to the amorphous nature of the compounds.

9817287
Kanatzidis
This research project will explore the synthesis of new solid-state chalcogenides using special low melting fluxes with an emphasis on understanding materials crystal structures and properties. A focus will be on controlling the stabilization of particular structrual building blocks, learning how to rationally stabilize quaternary and quinternary chalcogenide compounds, exploring new reaction types, and studying the nature of new charge density waves and superstructures occurring in some layered tellurides.
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The development of new solid-state synthetic tools often leads to exciting new materials with useful properties of high interest to the device physics community. The materials developed will be routinely screened for various important chemical and physical properties, and promising materials will be studied further and their potential applications evaluated.

This collaborative group award supporting the research of T.J. Pinnavaia, M.G. Kanatzidis, S.J.L. Billinge, S.D. Mahanti and M.F. Thorpe at Michigan State University is supported by the Chemistry Division. The focus of the research is the design, synthesis, characterization and computational simulation of disordered inorganic nanostructures. Two types will be explored, oxides, typically silica and alumina, and non-oxidic mesoporous structures, typically chalcogenides. Hydrothermally stable oxide mesostructures will be made by self-assembly using neutral surfactants as templates. Framework structures and heirarchal particle structures, i.e. vesicles, thin films, and porous clay heterostructures, will be made and characterized as a function of the surfactant and processing conditions. Characterization will be by small angle x-ray (SAXS) and neutron scattering (SANS), transmission electron microscopy and atomic pair distribution function (PDF) analysis of powder diffraction patterns. Pillared lamellar chalcogenides will be prepared by templating metal sulfides around thiol-ligated gold particles. Transition metal chalcogenide frameworks prepared by surfactant templating will combine semiconducting phenomena with accessibility by guest molecules. Modeling of porous networks and simulations of the surfactant self-assembly process and diffusion and access in the mesostructures of interest will complement experimental studies.

Disordered inorganic oxide mesostructures with highly accessible framework pores and having high hydrothermal stability will likely find applications in liquid-phase catalysis and separations not achievable with conventional zeolites.
Metal chalcogenide mesostructures may be active hydrodesulfurization catalysts, electronic materials and sensor materials.

0079578
Kanatzidis

Many of the research programs at the Michigan State University are in need of modern Transmission electron microscopy (TEM) imaging and analytical capabilities. This grant provides equipment, which will function in support of research as well as the university's teaching and undergraduate collaborative research mission. This grant provides for a JEOL 2010F field emission transmission electron microscope or equivalent. The microscope along with several requested accessories would provide TEM resolution of 0.19 nm, STEM resolution of 0.17 nm, electron holography, magnetic domain imaging, high angle annular darkfield imaging, convergent beam electron diffraction, energy dispersive x-ray spectroscopy, parallel electron energy loss spectroscopy, and energy filtered imaging. None of these techniques are presently available to University researchers. Numerous new scientific investigations would be enabled with the new equipment. The instrument will support research in a variety of material systems including semiconductors, ceramics, metals, polymers, new materials, biomaterials and mesoporous materials. The instrument will be housed at the Center for Advanced Microscopy, one of the University Core Facilities, that serves electron microscopy users from 49 different University departments. One staff academic position will be entirely devoted to the TEM to ensure adequate instrument supervision, user supervision, instruction, and technique development. Instruction on the TEM will be integrated into several existing electron microscopy courses that serve a broad range of users.
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Michigan State University is host to many scientific grants funded by NSF. Many of these programs are in need of a modern transmission electron microscope. These instruments are used to look at structure and interactions within matter. They are useful in many diverse fields such as chemistry, geology, materials science, physics, biology, and medicine. However, the present instruments at the University are in excess of 15 years old and do not have up-to-date capabilities. Many new imaging methods have been discovered in recent years that enable scientists to see structures never seen before and to determine information about matter never available before. Many of the scientists and students at the University could use this new equipment to make new discoveries. These discoveries have practical applications in electronics, sensor materials, catalysis, absorbent materials, materials for environmental clean-up, petroleum refining and understanding of global ecological changes. It will also significantly impact the discovery of new materials. Michigan State University has been given the funds to purchase a modern transmission electron microscope and to house it in the Center for Advanced Microscopy. This University Center will have one scientist in charge of this new microscope. That person will teach other scientists and students how to use it effectively in their research programs. Acquisition of this equipment will allow safe, effective training and research in electron microscopy of materials. The impact to the future education of students at MSU is expected to last for the next 15-20 years. Students from MSU will receive experience in using state-of-the-art instrumentation, whether they are bound for academics or a career in the private sector.

This renewal team award made to Michigan State University by the Advanced Materials Program in the Division of Chemistry is to study oxide and non-oxide mesoporous structured materials. With this award, Professor Pinnavaia and a team of other senior scientists with expertise in complementary research activities in synthetic inorganic chemistry, theoretical and experimental condensed matter physics, structural modeling and electronic structure calculations, and charge transport and thermal transport characterization will study the following: the oxide mesostructured materials; aluminosilicate mesostructure assembly from zeolite seeds and fragments with intrinsic acidic and hydrothermal stabilities; preparation of organofunctional mesostructures, wherein more than half of the framework metal atom centers are linked to accessible and reactive organic groups; mesostructure carbon replication for optically active monoliths using phase transfer assembly techniques with mesostructured silica as templates; and related experimental and theoretical studies for the assembly mechanisms and to elucidate the fundamental relationships between structure and performance properties of disordered oxidic mesostructures. This team will also study different chalcogenide mesoporous materials that act as the "inside-out" versions of array of quantum dots, narrow-gap semiconductors, biological iron sulfide clusters; and other electronically active, mesoporous chalcogenide solids with highly ordered pores yielding a variety of new materials with novel shape-selective redox, optical and electrical properties. The synthetic approaches will be complemented by characterization, modeling and theoretical calculations.

With this award, a team of scientists with expertise in synthetic inorganic chemistry, theoretical and experimental condensed matter physics, structural modeling and electronic structure calculations, and charge transport and thermal transport characterization will study oxide and non-oxide mesoporous materials. Active industrial collaborations for potential applications of these materials as catalysts will be part of these research activities. In addition, this highly collaborative effort will bring together materials scientists, chemists, condensed matter physicists and structural and theoretical scientists, and will provide educational and research opportunities for graduate and undergraduate students, postdoctoral associates and visiting scientists.

The goal of this project is to synthesize and characterize new solid-state materials in the metal thiophosphate and selenophosphate families. The metal thiophosphate and selenophosphates show a very rich chemistry that is based on anions that form in chalcophosphate fluxes by simple in-situ fusion, and these act as fundamental structural building blocks. Areas to be explored include alkali metal-free ternary metal-and rare-earth-metal- thiophosphates and selenophosphates, corresponding alkali metal quaternary derivatives and also glasses formed from the manipulation of these materials. Thioarsenate and selenoarsenate fluxes will also be explored to discover corresponding arsenic compounds. Characterization of the new materials will include structural determinations by single-crystal X-ray scattering methods and the measurement of physical properties such as optical absorption, thermal behavior and electrical conductivity. The structure of glasses will be probed with pair distribution function (PDF) analysis. The molten alkali poly-thiophosphate and poly-selenophosphate salts, which are the reactive solvents in this project, will be studied by Nuclear Magnetic Resonance spectroscopy in order to understand the identity, distribution, and chemistry of the anions that form in chalcophosphate fluxes. Eventually we wish to control the stabilization and incorporation of specified building blocks in synthetic target compounds. The ultimate goal of this research project is to enhance our knowledge of the chemistry of chalcogenides and render the
chemistry more controllable and predictable so useful new materials can be designed. This project has a very strong education component that aims to educate students in the advanced subject of solid state synthesis including non-oxide materials discovery and novel state-of the-art laboratory techniques.

The discovery of new classes of solid state materials with novel composition and structure, as well as an understanding of their chemical behavior and physical properties such as optical and electronic behavior are important to industry. For example, the glass versions of the metal-thiophosphate and -selenophosphates show controllable amorphous to crystal phase changes and may have potential for memory storage applications. Students trained in these areas are well poised to exploit current and future academic and industrial job opportunities.

This NSE Nanoscience Interdisciplinary Research Team (NIRT) focuses on one of the central problems in nanoscience research: How to determine the atomic structure within nanosize particles. This is an important issue because conventional crystallographic techniques are often rendered useless by the nanometer range of the atomic order. This project will develop novel approaches, particularly the atomic pair distribution function (PDF) method, for the study of nano-scale structure. These methods will be integrated with modern x-ray and neutron facilities via fast computer algorithms. The techniques will be applied to nanocrystalline materials, many of which have potential for technological applications. A goal of the project is to use the structure data in a kind of feedback loop involving modeling and synthesis to improve the properties of the materials under study. These include V2O5 xerogels and nanotubes, MoS2 and WS2 nanotubes and nanocrystals, passivated gold nanoclusters in dense forms and synthesized in biomimetic scaffolds, mechanically prepared GdAl2 nanomagnets, pharmaceutical drugs in amorphous and nanocrystalline form, alkali metal catalyzed nanocrystalline carbon and electronic nano-phase-separation in correlated-electron oxides. Facilities and software will be developed and made available via workshops to the broad community with interests in the structural properties of nanoparticles. The research is integrated with education, from undergraduate to post-doctoral level. This training includes laboratory research as well as sophisticated on-site experiments at national user facilities for synchrotron x-ray and neutron research.

This NSE Nanoscience Interdisciplinary Research Team (NIRT) focuses on one of the central problems in nanoscience research: How to determine the atomic structure within complex, nanosize particles and materials. Here, conventional tools for measuring atomic structure, x-ray and neutron crystallography, often fail. This project will address this shortcoming by developing novel methods that make use of modern national facilities and advanced high-speed computing to to determine atomic arrangements in nano-materials. The national facilities provide the unprecedented power of x-rays and neutrons that is required. This NIRT combines researchers with the expertise in novel structure determination methods with synthetic chemists and chemical engineers. Knowledge gained from the structural studies will be fed back into the sample synthesis steps to engineer nanostructured materials that have improved functionalities. An important aspect of the project is to create infrastructure in the form of dedicated facilities and software that can be used by others who wish to carry out similar investigations. New researchers will be trained through hands-on workshops, collaboration on specific projects, and by training graduates and undergraduates. The students will broaden their research experience by spending periods working in different investigators' laboratories and collaborating on experiments at national facilities. This will prepare them for careers in nanoscience and engineering in academe, industry, and government.

The present research program aims to expand the boundaries of what is possible in the solid state by pursuing and developing new synthetic methodologies for metal chalcogenides. The project deals with the effectiveness of salt fluxes to discover new materials in the broad chalcogenide class of compounds as well as with the in-depth studies of these materials. The need to control chemical reaction systems and to discover new materials through developing general synthetic methodologies defines one of the main challenges to our understanding of the relationships between chemistry, crystal structures, and properties in complex solids. Many of the relationships are subtle and poorly understood. In particular, the project focuses on complex ternary and quaternary metal chalcophosphate and chalcoarsenate materials. This class continues to present marvelous scientific challenges and it is broadly relevant to many technological applications. An extensive and diverse set of characterization tools will be applied. Exciting new materials are anticipated with interesting and potentially useful physical properties such as semiconducting behavior, non-linear optical activity, glass formation, and reversible phase-change crystal to glass transitions. The project will explore (a) lithium polythiophosphate and poly-selenophosphate fluxes to discover new alkali metal-free phases and also lithium-containing phases; (b) the synthesis of low valent selenophosphates and tellurophosphates (i.e. compounds with phosphorous atoms in a low valent state); (c) alkali metal polythioarsenate and polyselenoarsenate fluxes to further develop this chemistry and discover new materials; (d) investigation and study of the properties of glass forming systems occurring in certain chalcogenide stoichiometries.. These are called phase-change materials and are relevant in non-volatile data storage and computer memory applications. The results obtained from this research will enhance our understanding of chalcogenide phase stability, structure, bonding and properties. This project will educate and expose students in a worthwhile intellectual discourse. The students working on the project will receive outstanding training in synthetic solid state chemistry and materials research. They will acquire a direct awareness of the relevance of their materials to science and technology. The proposed activity will strive to furnish a meaningful, coherent research and education program for students so they, as future independent scientists, are able to synthesize, handle and manipulate novel classes of solid-state materials. Relatively few laboratories in the US provide this type of synthesis training. Undergraduate students also participate in this type of research, which has a lasting impact on their college laboratory experience and future career choices.

Non-Technical Abstract

New materials are at the core of many advanced technologies and products. This project seeks to discover new materials using novel synthesis techniques and to train students in the discourse of this type of research. The materials belong to the broader class of semiconductors and are expected to possess potentially useful physical properties and economic value. These include controllable electrical conductivity, photoactivity, glass forming properties and phase-change properties. In this project will investigate new phase-change materials which are relevant in non-volatile data storage and computer memory applications and in the sensing of chemicals in the environment. The methodology developed and the insights gained during this work, about the formation, chemistry and properties of unusual solids, could enable or facilitate useful technologies and thus could make an important contribution to science and could have a significant impact in a number of technologies and by extension on the US economy. Graduates and undergraduate students participate in this type of research, which is expected to have a lasting impact on their college laboratory experience and future career choices. The results of this research will be open to the public and will undergo peer-review before being published. The broad dissemination of scientific results and knowledge through the communications media, the web and journal publications will help enhance the public's awareness in the new knowledge being generated as well as its scientific understanding and appreciation of science.

Non-technical abstract:

A holy grail of nanotechnology is to design and build a material with some desirable property by engineering the atomic structure at the nanoscale. A huge impediment to this is the nanostructure problem: the fact that the established quantitative methods for determining atomic structure fail for nano-sized objects. This project addresses this problem with a collaboration of experiment and theory. The experiments utilize the intense beams of x-rays and neutrons available at US national user facilities combined with novel computational approaches for extracting reliable structural information from the data. In addition the local structure of intermediate states will be studied using ultra-fast femtosecond time-resolved electron diffraction, coupled to the same computational infrastructure, allowing us for the first time to probe quantitatively the local structure of excited states of nanoparticles. In this study a number of scientifically and technologically interesting materials will be studied, including quantum-dot nanoparticles and phase-change materials used in writable CD and DVDs. However, the theoretical and methodological developments will be made available to the wider scientific and educational community in the form of freely available software so the methods can be widely applied. In addition to training graduate and undergraduate students in state-of-the-art research, nanotechnology will be taken to the classroom in grades 6-12 and new hands-on nanotechnology modules will be built in collaboration with Everett High School, an inner city Lansing high school. A new curriculum and course content for an AP course will be developed with their active participation. This project is co-supported by the Condensed Matter Physics and Solid State Chemistry programs.

Technical abstract:

A holy grail of nanotechnology is to design and build a material with desirable properties by engineering the atomic structure at the nanoscale. A huge impediment to this is the nanostructure problem: the fact that the established quantitative methods for determining atomic structure fail for nano-sized objects. This collaborative project addresses this by using novel approaches for analyzing and modeling x-ray and neutron scattering data from nanomaterials. The data will be Fourier transformed to obtain the atomic pair distribution function (PDF) which will be modeled using novel approaches that will be developed such as encoding chemical information as geometrical constraints in the model. The analysis will be extended to electron diffraction data and combined with ultrafast techniques to study local structure quantitatively on femtosecond time-scales. The systems under study include novel electronic and optical materials such as low-dimensional charge-density wave tellurides, quantum-dot nanoparticles and phase change materials that are used in writable CDs and DVDs. The methods developed here will be made available to the broad community of nanotechnology scientists through training and free software. In addition to training graduate and undergraduate students in state-of-the-art research, nanotechnology will be taken to the classroom in grades 6-12 and new hands-on nanotechnology modules will be built in collaboration with Everett High School, an inner city Lansing high school. A new curriculum and course content for an AP course will be developed with their active participation. This project is co-supported by the Condensed Matter Physics and Solid State Chemistry programs.

This project investigates the use of novel materials specially designed for high resolution room-temperature identification of ã-rays emitted from fissile materials. This effort will enhance the state of the science and body of knowledge for highly dense, heavy element semiconductors with relatively wide energy gaps. The proposed project has the potential to be transformative in nature because it will identify new materials for sensitive ã-ray detection using a new idea for materials design based on the concept of ?dimensional reduction? of covalent frameworks. Using crystal growth techniques, we will grow and survey a variety of semiconducting compounds to validate their energy gaps and their resistivity. A minimum room temperature resistivity of ~108 Ohm-cm is required in the desired materials in order to allow for larger biases to be applied, resulting in faster carrier drift velocities and deeper depletion depths in the detection device. For the highest Z materials, the so-called Fano noise can also be substantially decreased (and thus energy resolution improved), by choosing compounds such as the chalcogenides proposed here. The materials will be characterized and tested in both crystal and device form for ã-ray detection. Theory-based materials design will depend strongly on knowledge-based optimization of the desirable properties of high Z wide gap semiconductors. The selection process and experimental approach will also rely closely on theoretical guidance. This is a close interdisciplinary collaboration between synthesis, measurement and theory involving groups with complementary skills.

1048622 / 1048621 / 1048728
Heremans / Lu / Kanatzidis

This project involves researchers from Ohio State University, Northwestern University, and Virginia Polytechnic Institute and State University, with input from industries. Working together, the researchers hope to solve major scientific barriers to commercializing thermoelectric waste heat recovery technology. The goal of project is the creation of a viable system to convert automotive waste heat into usable electrical power using thermoelectric (TE) devices.

Intellectual Merit: The research proposed here will advance work in TE by focusing on five key elements. Materials research (led by OSU and NU) will develop advanced TE materials made from earth-abundant, geographically dispersed elements and compounds, specifically PbSe and Mg2Si-Mg2Sn. Thermal management system design (led by BSST) will create new thermal designs to minimize losses by minimizing the number of interfaces, minimizing the amount of TE material used; these designs will maximize the durability of the product. Work on interfaces, led by VPI&SU and ZTPlus, will focus on the metallization of the TE materials and device interconnection and the flexible bonding of the metallized elements to the heat spreaders to increase durability and reduce device level performance losses. The team will expand capabilities in metrology to measure electrical and thermal contact resistances, and develop a comprehensive and redundant measurement loop system with self-consistent error checking. Durability will be the inherent design criterion in every invention.

This project has the potential to transform progress in TE materials. We will improve the fundamental understanding of the effect of resonant levels on the transport properties of solids, and make it applicable to large classes of semiconductors. The development of matrix encapsulation techniques for Mg2X will expand the repertoire of creative solid-state chemistry approaches in creating nanostructured thermoelectrics. New strong and flexible high-temperature bonding techniques will impact the assembly of semiconductor die. The project will advance understanding on the efficiency of TE generators, TE material durability at high temperatures, and cycle life durability of TE materials, all of which are critical to successful commercialization.

Broader Impacts: This project will create potentially transformative research that promises to save up to 800,000 barrels of oil daily and reduce carbon emissions. Results of the research will be incorporated into classes taught by project investigators in the physics of transport phenomena, materials synthesis and electronic component assembly. The academic PI's will also integrate this research into participation in multidisciplinary collaborative groups. The significance of energy efficiency and usage that this research addresses will be integrated into the well established outreach programs at all three universities. Involvement of corporate partners ensures large scale commercialization, as BSST is the world leader in commercial applications of TE's in automotive and other key industries.

TECHNICAL SUMMARY

The primary goals of this research supported by the Solid State and Materials Chemistry program are to discover and characterize new types of metal chalcogenide compounds and to develop and understand their structures, chemical bonding and physical properties. An important question of this synthesis program is whether we can guide the fundamental reaction chemistry occuring in salt fluxes at intermediate temperatures in order to suppress the formation of undesirable compounds and favor the crystallization of new ones. The project employs alkali metal polychalcogenide flux syntheses to afford materials containing condensed chalcogenide units. Well-defined building blocks are present in the flux reactions and their formation is guided by tuning the flux composition and temperature, which controls Lewis basicity and redox potential. In addition, the salt fluxes can sustain tunable dynamic equilibria that are important for the synthesis to be directed towards new metal chalcogenide materials. It is hypothesized that manipulation of these flux properties will allow the control of the synthetic routes toward a variety of new structures. The metals employed in this chemistry are primarily main group and rare earth metals and in select cases, transition metals. New materials of the chalcogenide class are expected with attractive chemical and physical properties such as ion-exchange, semiconductor (with a wide range of energy band gaps from 0.5-3.0 eV depending on structure and composition), metallic, phase-change and nonlinear optical properties (particularly very strong second harmonic generation in the infrared region). It is anticipated that many of the physical properties of the new materials will have significant potential for technological impact and further development in applications.

NON-TECHNICAL SUMMARY

Synthesis and crystal growth of new materials is increasingly recognized as an important underpinning of research that strongly impacts the physical sciences and thus programs such as the proposed one are both relevant and timely. Under this Solid State and Materials Chemistry funded program new chalcogenide materials are anticipated with useful chemical and physical properties such as ion-exchange, semiconductor (with a wide range of energy band gaps from 0.5-3.0 eV depending on structure and composition), metallic, phase-change and nonlinear optical properties (particularly very strong second harmonic generation in the infrared region). A wide variety of experimental characterization tools are employed in this project including single crystal and powder X-ray crystallography using in-house and synchrotron radiation, solid state optical, infrared and Raman spectroscopy, scanning and transmission electron microscopy, differential thermal analysis and scanning calorimetry, and measurements of electrical conductivity as well as optical second harmonic generation. It is anticipated that many of the physical properties of the new materials will have significant potential for technological impact and further development in applications.

At a grassroots level, the solid state and materials chemistry community recognizes the grand challenge of developing rational materials discovery strategies. This project helps address this challenge by developing new synthesis methodologies. For the class of chalcogenides, a rational, science-driven foundation is set to extract maximum scientific and technological benefit.

The specific focus is on training and teaching graduate students in solid state and materials chemistry who understand the importance of developing new materials as drivers for new technologies. The project provides important opportunities for graduate and undergraduate students to learn research investigative skills that are needed for contemporary materials chemistry research. The students are also exposed to a broad battery of physical property characterization tools. Student training in the synthesis and crystal growth of novel materials has a positive impact on our national competitiveness in key materials and addresses a growing national need. Students also benefit from high impact interdisciplinary collaborations. Finally, the broad dissemination of scientific results and knowledge through publication will enhance scientific understanding and hopefully stimulate further research activity elsewhere.

Non-technical Summary
New materials impact not only the physical sciences but also economic growth. At a grassroots level, the solid state and materials chemistry community recognizes the grand challenge of developing rational materials discovery strategies and identifying materials that are transformative in our understanding of physicochemical properties and in technological progress. With support from the Solid State and Materials Chemistry Program in the Division of Materials Research, this project help address this challenge by developing the chemistry of metal chalcogenides. In this context, the research team is building a rational, science-driven foundation to extract maximum scientific and technological benefit. The primary goals of this projecct are to discover and characterize new types of metal chalcogenide compounds, and to understand their structures, chemical bonding and physical properties. If successful, new materials enabling new applications or enhancing the effectiveness of existing technological applications will emerge. The project employs molten salts as powerful reaction media in which to seek formation of new materials with unusual physical properties. The project contributes significantly to the training and teaching of graduate students in the field of solid state and materials chemistry and helps to create a future workforce that understands the importance of new materials as drivers for new phenomena and technologies.

Technical Summary
The primary goals of this research are to discover and characterize new types of metal chalcogenide compounds, and to understand their structures, chemical bonding and physical properties. The project employs salt flux syntheses to seek new materials with novel structure and compositions. Well-defined building blocks are present in the flux reactions and their formation is guided by tuning the flux composition and temperature, which controls Lewis basicity and redox potential. An important question in this synthesis program is whether, using intermediate temperatures, one can guide the fundamental reaction chemistry occurring in molten salts to suppress the formation of undesirable compounds and favor crystallization of new ones. The project is based on the general theme of structure-composition-property relationships with the following question being central: How does one develop the tools and concepts, both intellectual and experimental, to discover new functional materials. Focusing on the chalcogenide class the project has the following directions: (a) synthesis in polychalcogenide fluxes focusing on early transition and main group metals, mixed metal systems and also on thio and telluro-arsenate and antimonate chemistry; (b) synthesis using mixed chalcogenide fluxes incorporating oxide salts; (c) creation of novel glasses from the crystalline compounds and their phase change behavior and (d) dissolution studies of selected promising chalcogenide phases to assess their potential for processing into more useful forms. The project is expected to enrich the knowledge of unusual and diverse chalcometallate building blocks and role they play in creating new compounds. Experimental characterization tools to be employed include X-ray crystallography optical, infrared and Raman spectroscopy, scanning and transmission electron microscopy, differential thermal analysis and scanning calorimetry, and measurements of electrical conductivity as well as optical second harmonic generation.

PART 1:   NON-TECHNICAL SUMMARY
Research in discovering new solid state materials addresses the grand challenge of moving towards rational materials synthesis that transforms our understanding of materials properties and advances new technologies. This project, which is funded by the Solid State and Materials Chemistry Program in the Division of Materials Research, focuses on discovering and characterizing new types of metal chalcogenide compounds using molten metal salts as solvents. Chalcogenides are used in a broad variety of scientific investigations and technologies. This project studies how important physical properties change as a function of composition and crystal structure of the metal chalcogenide. This leads to exciting new materials, which are expected to spark new applications or enhance the effectiveness of existing technological applications. Thereby new materials impact both the physical sciences as well as economic growth. Furthermore, this project contributes significantly to the training and teaching of graduate students in the field of solid state and materials chemistry and helps to create a future workforce that understands the importance of new materials as drivers for new phenomena and technologies. The project provides important opportunities for graduate and undergraduate students to learn research investigative skills that are needed for successful contemporary scientific research, which in turn has a positive impact on our national competitiveness.


PART 2:   TECHNICAL SUMMARY
This project, funded by the Solid State and Materials Chemistry Program in the Division of Materials Research, investigates the class of metal chalcogenides which occupies a vital place in chemistry, physics and materials science. These compounds exhibit remarkably diverse compositions, structures and physical properties which are at the core of many fundamental studies. Specifically, the project investigates (a) study the synthesis of Li containing chalcogenide phases to meet the challenge of incorporating this light alkali ion in a variety of structures; (b) the synthesis of complex alkali chalcophosphates with low-valent phosphorus to observe new bonding motifs and (c) the study of how metal chalcogenide ion-exchangers bind heavy metals. The fields of science and technology impacted by chalcogenides are important and continue to expand. Examples include nonlinear optics, energy conversion, information storage, batteries, topological insulators, catalysis, and superconductivity. The project focuses on ternary and quaternary chalcogenides because they promise very attractive or even unique chemical and physical properties. The main objective of this program is to further develop the ability to control chemical reaction systems by developing the general synthetic strategies that lead to new chalcogenide materials. New horizons in chalcogenide chemistry that pose great challenges are being explored.

This award is supported by the Major Research Instrumentation and the Chemistry Instrumentation Programs. Professor Mercouri Kanatzidis from Northwestern University and colleagues Kenneth Poeppelmeier, Sossina Haile, Steven Jacobsen and Danna Freedman are acquiring a single crystal X-ray diffractometer equipped with a silver micro-source, goniometer, and an efficient detector optimized for silver-radiation. In general, an X-ray diffractometer allows accurate and precise measurements of the full three-dimensional structure of a molecule, including bond distances and angles, and provides accurate information about the spatial arrangement of a molecule relative to neighboring molecules. The studies described here impact many areas, including organic and inorganic chemistry, materials chemistry and biochemistry. This instrument is an integral part of teaching as well as research and research training of undergraduate and graduate students in chemistry and biochemistry at this institution where students receive hands-on access to the diffractometers and collect data on their own experimental samples. The new diffractometer is also used for the biannual international Summer School co-organized with the American Crystallographic Association and Northwestern University. Collaborations are in place with other research institutions such as the University of Chicago, the Ohio State University, Illinois Institute of Technology, Loyola University Chicago, Lake Forest College and Roosevelt University.

The award is aimed at enhancing research and education at all levels. It is especially used for exploring solid state chemistry of chalcogenides and analyzing solid-state-related electrochemical processes. The diffractometer is also utilized for the analyses of synthesized compounds and minerals as well as synthesized oxides and oxide-fluorides. The instrument is employed in projects with applications in sustainable energy, geology, planetary sciences, ceramics and nanomaterials.

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.

PART 1: NON-TECHNICAL SUMMARY
The continued advancement of society on many levels relies on the steady use of new materials that can enable new functions or solve long-standing problems and challenges. Solid state materials underpin many products and processes on which our modern society depends. This project deals with the broader question: How do we discover and synthesize new solid state materials? It develops the fundamental science and principles of synthesis and how they can be used as tool to design and synthesize useful new materials. Specifically, the project, supported by the Solid State and Materials Chemistry program within the Division of Materials Research, focuses on developing the chemistry of metal chalcogenides. Chalcogenides are compounds of sulfur, selenium and tellurium and they are important in a broad variety of scientific investigations and technologies. The project pursues chalcogenide materials discovery as a science coupled with the study of crystal structure, physical properties including ion-exchange, charge transport and photo-response of the new materials. The primary goals are to learn how reactions leading to solid state chalcogenides can be controlled so known materials can be avoided and new materials can be accessed. This research activity enhances, as well as challenges, our scientific understanding. It will also enhance the effectiveness of existing technological applications and impact new applications. Possible technological impact could be via new semiconductors, materials with high Li mobility, quantum materials and ion-exchange sorbent materials for environmental remediation. The project provides diverse opportunities for graduate and undergraduate students, including those from underrepresented groups, to learn critical thinking skills that will help advance future scientific research. Additionally, the educational program encompasses outreach to high schools on ion exchange materials and dissemination of YouTube videos on safe use of the advanced synthetic methods used in the project.

PART 2: TECHNICAL SUMMARY
This project pursues chalcogenide materials discovery as a science coupled with the study of crystal structure, physical properties including ion-exchange, charge transport and photo-response of the new materials. Within an overarching theme of contributing to fundamental understanding of synthesis, particularly using flux-based methods, the project studies: (a) the understanding the synthesis of complex Li-containing chalcogenide phases; (b) the formation of stable boron clusters as building blocks in chalcogenides; (c) the understanding of the synthesis routes that lead to subchalcogenides with low-valent metals; (d) the rational design of ion-exchangers. The expected benefits are: i) broad new insights regarding the reactivity and stability of lithium-containing chalcogenide phases; ii), expansion of the small class of the little-known boron cluster-based chalcogenides; iii) new chemistry and bonding in subchalcogenides and their impact on physical and chemical properties, and iv) delineation of the factors involved in the selective binding of heavy soft metal ions by metal sulfides ion-exchangers and use of this knowledge to create novel compositions using ion-exchange chemistry. Possible technological impact of these materials could be new semiconductors for radiation detection, materials with high Li mobility, topological quantum materials, open framework systems, and ion-exchange sorbent materials for environmental remediation. This project is supported by the Solid State and Materials Chemistry program within the Division of Materials Research.

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.