Unraveling the microscopic dynamics of coupled energy states in nanostructures
Abstract
The influence of chemical and structural heterogeneities on the fundamental energy carrier scattering processes not only plays an important role in dictating the physical properties of materials but also controls the efficiencies of a wide array of microelectronic devices. However, the current understanding of these microscopic scattering processes occurring at ultrafast time scales is mainlylimited by the lack of experimental and computational tools capable of fullthe necessary experimental metrology in conjunction with advancements in atomistic simulations to provide unparalleled insight intothe coupled energy states of photons, electrons, and phonons and how these interactions affect the overall thermophysical properties of nanostructured materials. The comprehensive knowledge of energy carrier scattering processes in and around regions of heterogeneities will enable materials design with an end goal of achieving multifunctional properties through the manipulation of these processes. Therefore, the outcomes of this project are expected to revolutionize the future of the Navy s electronic technologies through new directions in manipulating energy and charge transport processes. For example, the coexistence of "user-defined" thermal, charge-carrier, and mechanical properties in heterogeneous materials could lead to the efficient, on-site, and on-demand mitigation of hotspot generations in high-power electronic devices used in the Navy s ships. This will circumvent the currently used bulky packaging and system-level solutions for thermal management, thus guiding the future design of the Navy s electronic technologies for enhancing their safety and efficiency requirements.Specifically, a nanoscale thermometry technique capable of sub-micron lateral resolution and picosecond temporal resolution will be developed, which will enable spatial imaging of energy relaxation processes in real-time resulting in "movies" of the energy carriers in materials. This new technique will enable high-fidelity measurements of thermophysical properties that are otherwise not accessible with current experimental tools due to the lack of sensitivity of the measurementsto the desired properties. The newly formulated metrology will be implemented to image the microscopic dynamics of the energy carrie two-dimensional covalent organic frameworks. These novel materials provide the perfect testbeds to study the influence of structural anisotropy, interfacial effects, nanoporosity, and solid-gas interactions on the various thermophysical properties. Advancements in the computational approach based on combining molecular dynamics simulations with first-principles-based electron-phonon couplingcalculations will corroborate the experimental findings by providing the spectral- and mode-level understanding of the fundamental energy carrier scattering processes.The implementation of these pioneering methodologies will comprehensively answer the following questions on the fundamental behavior of energy carriers: (i) How does the internal morphology affect the thermal properties in molecular heterostructures? (ii) How does doping the nanopores with gas molecules influence heat diffusion in 2D framework materials? (iii) How do the choice of the molecular building blocks and structural non-idealities affect the electron-phonon coupling, electron diffusivities, and ultimately the transport properties in polymeric crystals? (iv) How do the structural and chemical heterogeneities influence the unique mechanical properties such as the realization of high negative Poisson s ratio and modular elastic properties in polymer networks?
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 05, 2021
- Source ID
- N000142112622
Entities
People
- Ashutosh Giri
Organizations
- Office of Naval Research
- United States Navy
- University of Rhode Island