Max Shtein, Ph.D. - US grants

0523986
Shtein

Near-field Scanning Optical Microscopy (NSOM) has demonstrated sub-wavelength spatial resolution and has been applied to a broad range of systems. However, a combination of illumination geometry, absorption losses in the tip, and photobleaching in purely optical NSOM techniques results in low signal-to-noise ratios, severe tip heating, sample degradation, and unpredictable response. A different means of localized, on-demand photon generation is needed to further improve the measurement.

The proposed research addresses these challenges by studying the effects of nanometer scale confinement of charges and excitons in organic semiconductors. A multifunctional scanning nano-probe tool will be fabricated, consisting of an electrically pumped organic light emitting diode (OLED) deposited inside of a nanoscale cylindrical cavity in the vertex of a scanning probe cantilever.

Intellectual Merit: The proposed nano-OLED probe will be 100 times smaller than individually addressable OLEDs made to date, providing a powerful platform for investigating surface interactions that influence the performance of other nano-scale devices. This will result in greater understanding of the fundamental mechanisms and scaling laws of charge and energy transport in functional organic materials. This will in turn enable improvements in the performance characteristics of large-area organic optoelectronic devices. The ability to electrically pump the probe will allow the study of sensitive biological materials, photonic devices, and materials. The proposed research will also examine fundamental issues of molecular transport in highly confined geometries, as well as organic deposition techniques having broader applications in nano-fabrication.

Broader Impact: As a new NSOM technique with electrical pumping and tunability, the nano-OLED probe can become the optical equivalent of STM, enabling new applications such as a read-write head for nanoscale optical bit storage elements and tunable nanosensor arrays. Studying the confinement of light and charge carriers, as well as nanofabrication using organic materials, can impact the development of electrically pumped organic lasers, and the integration of tunable light sources and sensors with nano-scale electronic circuits. The nano-OLED probe will enhance research and education infrastructure by providing novel instrumentation for the study of nanosystems. Through its interdisciplinary nature, this project will train students in the emerging fields of organic electronics and nano-fabrication. The research results will be integrated into the curricula of at least two departments, promoting teaching and training that will enable further and collaborative studies in the state-of-the-art nanoscale characterization and processing tools.

The objective of this research is to develop a novel, organic-based electrically pumped plasmonic amplifier, utilizing the strong coupling of surface plasmons and excited molecules observed only at nanoscale distances. The approach is to build resonant plasmon cavities with nanoscale metallic patterns. The cavities will serve as a basis for two devices that enable the conversion of signals between the electrical and plasmonic domains.


The intellectual merit of the proposed work consists of: 1) characterizing the coupling of electrically pumped molecular excitations to guided surface plasmons in nanostructured metal films, 2) demonstrating nanopatterned ring structures for high-quality in-plane plasmon resonators, 3) achieving gain in these plasmon resonators, and 4) investigating the potential of utilizing surface plasmon gain to achieve electrically-pumped stimulated emission of plasmons.


The broader impact of this work will be the realization of either an electrically-pumped plasmon amplifier or an electrically-controlled plasmon source. These may enable a radically new type of integrated circuit that can help extend Moores law beyond the limitations of current integrated circuit technology. Tailoring the decay mechanisms of electrically excited molecules in resonant cavities can contribute to the realization of organic lasers and the general field of molecular electronics. The PIs will involve graduate students as well as undergraduate students and high school students in their research though a recently established program with Green Hills High School, encouraging female and underrepresented minority participation. Past participation in this program has demonstrated high levels of interest among K-12 teachers and students.

Technical Abstract:
Organic semiconductors comprise a scientifically and technologically important class of materials, in-tensively researched for applications in electronic and optoelectronic devices. This class of materials of-fers tunable electronic/optical properties which exhibit remarkable physical properties, and can be depos-ited as high quality thin films on a variety of substrates, including low cost glass and plastic, potentially enabling cost-effective, large-area electronics and energy conversion devices. In the course of research involving organic semiconductors, exotic molecules are engineered and synthesized, and subsequently incorporated into devices. Unfortunately, exploratory synthesis yields are often low (resulting in < 10-3 g quantities), and costs of device fabrication are high (> $105 for equipment). Moreover, the materials utili-zation efficiency of currently employed thin-film deposition techniques is often less than 0.01%, leading to a range of practical limitations on the pace of experimental exploration and increasing potential health hazards to the researchers.
To address these problems, we will develop a Guardflow-enhanced Organic Vapor Jet Printing (G-OVJP) deposition system that allows compact and cost-effective deposition with much higher (50%+) source material utilization. The vapor jet technique employs a carrier gas to deliver source molecules onto a substrate, increasing materials utilization by bringing the sample into close proximity of a collimated source. The specially designed guard flow shields the stream of the source material from the surround-ings, thereby allowing the deposition to take place in a highly localized inert environment, potentially enabling device printing in atmosphere.
The potential impact of the proposed work includes greatly reducing the cost-of-entry for organic op-toelectronics research, facilitating cross-disciplinary collaborations, enabling access to materials and mor-phologies not available via existing deposition techniques, and an accelerated pace of discovery in the realm of scientifically and technologically important organic semiconductors.

Non-technical Abstract:
A relatively novel class of carefully engineered organic materials derived from pigments is becoming increasingly important in science and technology. The accelerated pace and volume of research directed towards molecular organic semiconductors is motivated in large part by the ability to span a vast range of properties by means of chemical synthesis, and by the potential ability to cost-effectively fabricate futur-istic devices (e.g. ultra-thin bendable displays, efficient lighting wallpaper, plastic solar cells, health-monitoring devices, and others).
Unfortunately, present research activities are severely limited by the high costs of processing equip-ment, waste of exotic new materials due to inherent inefficiencies of the laboratory-scale processing methods employed, and the serial and slow nature of experimentation imposed by the current crop of processing equipment and methods.
The proposed research apparatus - Guardflow-enhanced Organic Vapor Jet Printer - will increase ma-terials utilization efficiency by orders of magnitude, free up laboratory space, reduce capital costs, im-prove safety, speed up laboratory-scale fabrication and testing of novel devices, and enhance scientific collaborations across traditional disciplinary boundaries. The benefits of this proposed work will extend beyond the research community, to undergraduate and K-12 education, by providing greatly simplified and more rewarding hands-on experiences in science and technology at the cutting edge of research in organic semiconductors and energy conversion devices.

This project is based on a partnership between three research groups, one at the Science and Analysis of Materials (SAM) Department at the G. Lippmann Research Center in Luxembourg and two at the Materials Science Department of the University of Michigan (UM). This partnership merges resources that are not available to each participant individually. The purpose of this research is to investigate the shape, compositional definition, and energetics of interfaces in vapor-deposited multi-layer organic semiconductor thin films and devices fabricated by one of the UM groups. The increasing sophistication of optoelectronic devices requires molecular-level dimensional control in the fabrication of multi-layered structures with specifically engineered interfaces. However, the effectiveness of growth and doping strategies devised to achieve the desired device structures oftentimes remains unverified due to the lack adequate characterization techniques. This is particularly true for devices based on conjugated organic compounds, which find increasing use in energy applications (e.g. organic light-emitting diodes and organic photovoltaic cells, etc.). The buried interfaces are simply inaccessible or suffer damage when using conventional characterization techniques. Low-energy secondary ion mass spectrometry (LE-SIMS), a specialty of the SAM group, provides a promising avenue for the analysis of organic-based thin-film layered structures, because sub-keV impact energies of the primary ions result in reduced fragmentation of molecular species at the specimen surface. The physics of the collision cascades and the processes that lead to the ejection of secondary ions at low energies is still poorly understood, and a unified formalism for the identification of ejected species does not yet exist. Pursuing this knowledge, the other UM group combines large-scale molecular dynamics (MD) simulations with first-principles density functional theory (DFT) calculations to study the detailed atomic trajectories in collision cascades and predict the nature of ejected molecular fragments. This computational framework serves to interpret experimental data obtained from LE-SIMS, thereby improving the depth resolution of the technique and its ability to reliably identify organic molecular species, thus further establishing LE-SIMS as a technique for depth-profiling organic thin film materials.

The goal of this project is to establish the relationship between growth conditions, structure, and properties of multi-layer thin film organic semiconductors with unprecedented precision. Fundamental insights for the advancement of organic electronic device design and fabrication techniques are anticipated. The project serves as the basis for three Ph.D. theses. Students benefit from a diverse educational experience through exchange visits to partner institutions, remote interactions between researchers, sharing of data, and the use of cyber infrastructure for the dissemination of findings through. Undergraduate students are involved directly at an academic level, and K-12 students through new outreach initiatives at UM.

The research objective of this Emerging Frontiers in Research and Innovation (EFRI) Origami Design for the Integration of Self-assembling Systems for Engineering Innovation (ODISSEI) award is to study how the folding of planar sheets can produce novel, three-dimensional, functional structures ranging from millimeters to nanometers in size. Special "nanostructured paper" will be created, comprising thin films and membranes containing a variety of functional nanoscale objects (e.g. carbon nanotubes, semiconductor and metal nanoparticles, etc.); the nano-paper will be etched and perforated to facilitate controlled folding into more complex shapes, which can be programmed to respond to impulses and pre-determined conditions such as local and global changes in temperature, humidity, and light. The research will examine how folding can be triggered by mechanical strain, external electrical or magnetic fields, and local laser heating. Using a combination of experiments and computer modeling, the fundamental principles governing the creation and transformation of sheets into three-dimensional (3D) objects will be studied, in particular focusing on how the size of the object influences the folding dynamics. This knowledge should help resolve significant challenges of materials integration into complex and robust 3D structures for, e.g., the control of light propagation in energy conversion devices, scalable fabrication of optical and electromagnetic metamaterials, and engineering of reconfigurable "smart" surfaces powered by changes in ambient conditions.

If successful, this research can address broader technological and societal challenges, including those in the areas of renewable energy harvesting, energy efficiency, water purification, environmentally benign microfabrication, etc. Specifically, this work may result in novel approaches to the design and deployment of focal plane arrays, beam steering, dynamic control of radar signatures, thermal management, and other applications. Paper folding techniques (www.mattshlian.com) will be used as a means of inspiration, realization, and visualization of structures at larger scales, and will provide design principles for scale-independent miniaturization. Special sessions on ?origami electronics? will be conducted at the scientific conferences attended by the investigators. The visual and hands-on nature of the research is likely to resonate with a wide range of students and audiences, which will be reached through summer workshops on origami and its technological applications. Further outreach activities will include exhibiting at the world-renowned Ann Arbor Art Fair, the Ann Arbor Hands-On Museum, and presentations at various arts / design / interdisciplinary conferences (e.g. Siggraph, ARS Electronica), as well as at traditional gallery venues for the arts (e.g. Detroit Institute of Arts, Cranbrook Academy, Urban Institute for Contemporary Art).

This project is supported in part by funds from the Air Force Office of Scientific Research.

Solar tracking is a mature technology that substantially increases the power output of a given photovoltaic (PV) module. Conventional tracking systems such as single and dual axis trackers have the potential to improve the overall efficiency of PV modules and thereby lower costs, but have not been widely implemented due to system complexity, high installation costs and the need for cumbersome structural components to support system weight and wind loading. Moreover, such tracking systems cannot be deployed in space-limited locations. This team has developed a new paradigm for lightweight and compact solar tracking based on the ancient art of Kirigami. This team's proposed technology has the potential to reduce the cost of photovoltaic modules and can be deployed in locations that are not accessible via the use of existing tracking technology such as mobile and residential (pitched) rooftops on account of its low-profile, compact nature.

Kirigami tracking modules consist of a simple kirigami-cut pattern integrated with thin-film solar cells, whereby pulling on the device results in a change in angle of the solar cells embedded on the substrate. By leveraging the unique geometric properties of the kirigami substrate itself, and the excellent electrical and mechanical properties of the thin-film solar cells, these devices can be used to efficiently track the sun. Due to the low-profile nature of kirigami tracking systems, there is no wind loading and, thus, no need for additional structural components to support such forces. Furthermore, kirigami tracking is lightweight in design, allowing one to eliminate much of the foundation and supporting structures that, in fact, make up much of the cost of conventional tracking systems. Due to the continuous nature of the kirigami substrate and the ability of all cells to be actuated simultaneously (unlike conventional tracking systems, where additional components are needed to connect each panel), system scaling is also relatively straightforward. Finally, by eliminating many of the components needed for conventional tracking and drastically reducing module size, this team believes that kirigami tracking will help open new market segments.

The development and manufacturing of cutting edge materials typically involves time-consuming materials and process design phases, followed by extensive testing of samples to adjust process conditions as the manufacturing scales up from the lab, to pilot plan, to industrial process scale. These distinct steps drive up the cost barrier to introduction of new and improved materials into the industrial pipeline and increase the cost of domestically manufactured advanced nanomaterials. Fortunately, recent developments in numerical modeling, additive manufacturing, and rapid testing of materials suggest that a new approach to material development and nanomanufacturing, where the previously distinct and time-consuming phases could be carried out nearly instantaneously to arrive at optimal material structure as well as process conditions for its manufacture. The focus of this award is to revamp the traditional, open-loop synthesis of nanostructured materials by: 1) using a versatile 3-D printing approach to manufacture these nanomaterials and nanostructures, 2) incorporate material property characterization directly into the printing process, and 3) use an artificial intelligence (AI) algorithm to adjust on the fly process conditions to achieve desired material properties. These concepts and components will be integrated into technical coursework, hands-on research opportunities, and outreach workshops to a broad range of students and the public. The co-PIs plan to leverage existing outreach and educational activities through their group's collaboration with a local museum, as well as curricular and extracurricular activities.

The approach and framework is an investigation of process modeling, materials synthesis and characterization, and system design to autonomously discover new material configurations and reduce manufacturing defects and uncertainty. This AI framework will "understand" process-structure-property relationships, manufacturing constraints, and, importantly, statistical variations in material properties and manufacturing quality. The intellectual merit of this study is the discovery of general nanomanufacturing tools and feedstocks, with supervisory genetic algorithms, that autonomously correct for defects and compensate for innate manufacturing inaccuracies by a search for alternative designs; this is in contrast to standard tools that minimize uncertainty (e.g. environmental controls) or rely on post-fabrication characterization with human intervention. The framework will be tested using nanoscale additive manufacturing (AM) as the fundamental manufacturing tool and nanostructured metamaterials as the application. The paradigm and nanoscale metamaterials made via this approach have far-reaching impacts on scalable nanomanufacturing for integrated systems. The paradigm of systems that autonomously evolve parameters to meet construct specifications is extensible to macroscale additive manufacturing and pharmaceuticals where the process parameter space and chemistries available is vast, and design is not intuitive. Additive nanomanufacturing has the potential to transform metamaterial design by enabling design in 3-dimensions (3D) with multiple materials, creating complex composite metastructures.

The broader impact/commercial potential of this PFI project will be to enhance the rate and cost-effectiveness of pharmaceutical research, development and manufacturing, ultimately lowering the cost of new, sophisticated medicines, as well as making it easier for people to take combinations of medicines required to combat some diseases. Many current practices in drug discovery and manufacturing are century-old, resulting in poor quality, poor patient compliance, poor scalability, and scarcity of many medicines. The proposed approach differs radically from existing practices in the pharmaceutical sector, enhances the properties of active ingre-dients in medicines, drives down the amount of solvents required for pre-clinical testing and thus reducing toxic chemical waste, yet is compatible with many existing drugs and dosage forms (e.g. pills, gel caps, patches, injections, etc.). If successful, the proposed technology could short-en by several years the drug development timeline, make it easier to combine multiple med-icines into a single pill or patch tailored to each patient, and reduce the amount of precious active ingredient being wasted due to body elimination or unused prescription medicines.

The proposed project has significant intellectual merit, in that it leverages techniques from the semiconductor industry and nanotechnology to address long-standing problems in pharmaceutical science, development, and manufacturing. The process at the core of this project can print active pharmaceutical ingredients (APIs) with precision and accuracy, while also enhancing their dissolution without resorting to strong or toxic solvents. It will advance understanding of thermal properties of pharmaceutical compounds, the link between molecular structure and crystal structure, and its influence on dissolution properties and bioa-vailability, which it enhances. While these capabilities have been shown for some compounds, they remain unavailable to the broader pharma research community. This multi-disciplinary project will make the capability widely available to molecular chemists, biologists, and pharmacologists, allowing them to devote more of their time to optimizing small molecular therapeutics for potency and site-specific binding, without facing solubility bottlenecks. The proposed work promises to unlock the therapeutic potential of millions of al-ready synthesized compounds that are languishing in material libraries due to their poor solubility, and to create combination therapies of unprecedented sophistication that will leverage deep learning- and data-driven medical science.

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.

Intellectual Merit:
This project proposes to develop a rapidly manufacturable novel N95 class respirator design platform that decouples the relationship between comfort and filtering efficiency. The majority of N95 respirator masks are worn improperly even by trained medical personnel, caused by improper donning and fit when optimizing for comfort instead of filtering efficacy. The proposed N95 respirators would enable the monitoring and minimization of face touching and track cleaning cycles and usage patterns. The project will circumvent several fundamental shortcomings in the design of current N95 style respirator masks, as well as their fit and wear protocols. The proposed design maximizes compactness, comfort, and manufacturability, while enabling real-time monitoring of face-touch events. The research team will use the latest advances in knitting technology that controllably place stiff and compliant elements in a seamless and semi-customized manner, sensing algorithms that can run on widely deployed wearable technology, as well as novel kirigami/origami-inspired sensor platforms and mechanical enhancement for filter effectiveness. Despite the advanced nature of these elements, the project will use current hardware and manufacturing capacity and plans to quickly transition to cost-effective implementation.

Broader Impact:
Studies have implied that gaps (as caused by an improper fit of the mask) can result in over a 60% decrease in the filtration efficiency, implying the need for future cloth mask design studies to take into account issues of "fit" and leakage, while allowing the exhaled air to vent efficiently. The knitting-enabled approach used in this project allows for N-95 class of masks to be manufactured with a wider variety of size and fit options, using industrial capacity that has not been used to date for medical-grade masks. Successful implementation of these designs will result in greater numbers of PPE produced and made available to healthcare workers. Although the proposed manufacturing process will be more costly initially, the mask construction will meet the necessary standards to allow for reusability and continued fit over time; significantly reducing its per-use cost. Furthermore, this approach to achieving semi- or fully customized fit of something as varied as the human face can be more broadly adapted to a variety of wearable garments and devices.

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.

On a dollar per mass basis, active pharmaceutical ingredients (APIs) are perhaps the most valuable chemicals in the world, and yet much of the mass of APIs in drugs taken is not absorbed in the body, entering the water supply and potentially harming human health and the environment. At the same time, despite rapid advances in the science of personalized medicine, and digital, additive manufacturing, the trillion-dollar-per-year pharmaceutical industry retains its century-old manufacturing processes and uses supply chain and distribution models that are potentially prone to tampering, contamination, and disruption. To address this problem, researchers and drug manufacturers have begun developing 3D printing approaches, as well as techniques borrowed from other industries (e.g. thin-film coatings) for drug formulation, dose customization, and release profile engineering. However, fundamental challenges remain with material compatibilities, ingredient dispersion in solvents or matrix materials, process control, and scalability. This fundamental research project aims to address these challenges by converging several new breakthroughs in additive manufacturing, molecular and crystallization modeling, surface science and engineering, and patient-specific in vitro disease models. This project will train students of diverse backgrounds, including women and minorities, and those concerned with patient care and safety, public health, drug costs, regulatory law and practices.

This fundamental research project will introduce a radically new approach to drug formulation and distributed manufacturing, offering new means of controlling crystalline structure, cocrystallization, and adaptation to different delivery vehicles. Currently, predictive model-based process design for organic crystallization processes is still in relative infancy. Likewise, processes for cocrystallization require further work to systematize coformer selection and prediction of conditions for cocrystal formation. The novel, solvent-free process used here offers possibilities for developing novel pharmaceutical cocrystallization research tools, as well as a path to scalable cocrystal manufacturing. The technology platform of controlled surface wettability patterns to enable low-cost dissolution assays, combined with the organoid assays will create new paradigms for on-site validation and control of product quality, which will be particularly beneficial in a distributed manufacturing setting. The organoid assays used could enable rapid testing of new medications in more realistic cellular microenvironments prior to human trials. This research will facilitate the path to accelerating the time from drug development to manufacturing and distribution, and help prevent potentially dangerous by-products or contaminants from reaching patients.

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.