Advanced materials are a crucial innovation area for fields vital to national security, including energy, defense, aeronautics, and aerospace technologies. Rice University materials scientist Boris Yakobson has secured three awards from two federal agencies, amounting to $4,140,611 over several years, to research the complex aspects of advanced materials production, performance, and dynamics.
Representation of an interface in a composite material. Image Credit: Yakobson Research Group/Rice University
The awards serve as a testament to Rice’s status as a nationally significant center for materials science research.
Building on previous research, Yakobson expressed his hope that the studies will “lead to discoveries that really transform how we understand, make, and work with advanced materials.”
A project titled “Mapping the Synthetic Routes for 2-Dimensional Materials” aims to uncover the molecular mechanisms necessary for producing 2D materials at an industrial scale and quality. These materials are intended for use in microchips and future electronics.
2D materials were initially produced through exfoliation, which involves "peeling off" atom-thin layers from a three-dimensional (bulk) crystal. However, this method is not ideal for large-scale production. Chemical synthesis-based methods require precise understanding and control of chemical reactions to grow crystal layers. Typically, these methods involve transforming the material from a solid to vapor and then back to solid form.
Solid-vapor-solid reactions are many and poorly understood, and scientific breakthroughs in several key examples must pave the way to new science at the crossroads of gas-phase reaction kinetics, nonequilibrium surface physics and emergent crystal structure.
Boris Yakobson, Karl F. Hasselmann Professor, Department of Materials Science and NanoEngineering, Rice University
According to Yakobson, he intends to investigate early quantum-level molecular dynamics using computational techniques to pinpoint the essential changes leading from unprocessed precursors to intermediate species and, eventually, to building units that come together to produce the desired crystal layer.
Yakobson added, “We are trying to answer questions such as can we accelerate crystal growth by adding extra components without compromising the quality of our product, or how can we create desired defect types in our resulting material that we can then use as current carriers, catalytic centers or single-photon emitters for qubits in a quantum computer.”
The goal of the Yakobson Research Group is to establish a general approach to the development of predictive synthesis models for perovskites, nitrides, oxides, and other materials desired for energy and electronics applications. This approach builds on previous work on several iconic 2D materials, such as graphene, molybdenum disulfide, and hexagonal boron nitride.
“We also aim to automate the search for reaction paths that would allow us to synthesize new, previously unknown materials or to simplify the production of materials like borophene, which now require expensive or esoteric techniques,” Yakobson stated.
The US Department of Energy will provide $2,107,997 over several years to fund his proposed study on 2D materials.
The US Department of Defense additionally granted the Yakobson Group a total of $2,032,614 over the following four years for two projects: one on the behavior of energetic materials in severe nonequilibrium states and the other on interfaces in composite materials.
Yakonson noted, “One of these projects looks at the atom- or molecular-level details of how interfaces — the borderlines between microcomponents in a mixed solid — respond to extreme load.”
Interfaces impact the overall performance of composite materials, and properties such as mechanical strength, toughness, electrical resistivity and thermal and corrosion stability are of critical importance in both civil and defense infrastructure and applications from bridges and railroads to submarines and supersonic aerospace vehicles.
Yakonson further added, “We plan to use state-of-the-art quantum chemistry computations to look at heterogeneous interfaces in order to determine how high-performance composite materials behave under extreme conditions and how we might improve their design.”
The second DOD-sponsored initiative will develop methods for estimating the rates of chemical reactions and other processes that occur in complicated systems that are far from chemical equilibrium.
“Systems that are far from thermodynamic equilibrium will exhibit significant spatial variations or gradients in terms of energy density, chemical composition and more, making it difficult to determine the speeds of processes. This is very important to know, especially for energetic materials, which are a broad class of materials that store a large amount of chemical energy,” Yakonson further stated.
Propellants, fuels, and explosives are a few examples of materials that are energetic. Yakobson aims to “make a dent” in the relative lack of understanding of the role played by stress-mediated reactions and the spatial heterogeneity of nonequilibrium systems in gas- and liquid-phase processes by utilizing insights from solid-state chemistry.
Yakonson concluded, “Harnessing modern computational technology will be immensely valuable for this project. We hope to advance from near-equilibrium science operating with, say, temperature gradients to modern dynamics of quantized phonons, vibrons, excitons and their coupling as the new toolset for describing the energy game far away from equilibrium.”