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Research

Mechanics & Physics of Heterogeneous Materials
Our research interests lie at the intersection of mechanics, computational materials science, and solid state physics.  We integrate a blend of classical and quantum mechanical methods to uncover the multiscale influence of deformational and compositional heterogeneity on structural and electronic properties of solids and nanostructured materials. Our objective is to understand fundamental mechanisms at the atomistic scales and apply the understanding to guide the macroscopic design of materials and structures with new or improved functionalities. Current efforts are focused on the following:


A. Multiscale Mechanics of Fracture in Heterogeneous Materials & Structures
(hybrid materials, composites, biomaterials, alloys)
Fracture is a prevalent failure mode in structural composites, aerospace structures, multi-junction solar cells, high temperature thermoelectrics, thermophotovoltaics, and battery. While successes in the field of fracture mechanics are impressive, it is also impressive how much remains unknown, particularly under heterogeneous conditions. Although several mechanisms (such as crack deflection, shielding, or bridging) have been proposed to influence fracture toughness in simpler heterogeneous constructions, a versatile approach relating toughness and heterogeneity is still to emerge, without which design principles remain bounded by inconclusive empirical approximations. We seek to apply the principles of quantum mechanics and classical mechanics and develop a comprehensive understanding of the relationship among heterogeneity, hierarchy, and toughness.    


B. Multiscale Mechanics of Energy Absorption & Transport in Thin-film Heterostructures
(thin-film alloy quantum dot photovoltaics, thin-film thermoelectrics)
We are investigating the role of mechanics in changing the way we look at enhancing efficiency in energy absorption and conversion materials -- such as solar cells and thermoelectric generators. Our aim is to understand energy absorption mechanisms in alloy-quantum-dot (AQD) thin film heterostructures and to construct new design principles for the integration of AQDs in photovoltaics and thermoelectric generators. Our research seeks to apply a physics-based mechanistic approach and open up new possibilities for engineering absorption by exploiting compositional and deformational heterogeneity.  


C. Mechanics of Energy Transport in Nanostructured Hybrid Materials
(2D and 1D materials, their assembly, polycrystalline structures)
Low-dimensional materials such as graphene or carbon nanotube show remarkable promise for next generation electronics (transistors), structural materials (composites), energy (thermoelectrics, solar cells), and biology (biosensors, drug delivery). Nonetheless, due to lack of structural stability they are highly susceptible to undergo mechanical deformation, which alters their pristine properties substantially, particularly in the vicinity of insulating substrates on which they are grown, electrodes that they are attached to, or the external reactive molecules they are exposed during operationsIn order to predict the mechanisms that causes alteration of the electronic behavior of the materials or to control the energy dissipation arising from localized interfacial deformation and its coupling with the long-range elastic fields, we are exploiting material heterogeneity as a design tool. The goal is to protect and enhance their pristine properties and predict new functionality by hybridizing materials at different scales and understanding their energetic correlations under various deformation conditions.