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On the Mechanics of 2D Alloy Sheets: Application to Transition Metal Dichalcogenides
David Srolovitz , City University of Hong Kong Chair: Chun-Wei Pao Time: 2019/12/19 08:30-09:10 (101, 1F1 TICC) |
Abstact:
The properties of 2D materials can be broadly tuned through alloying, phase and strain engineering. I will discuss two topics: the interaction between phase transformations in 2D transition metal dichalcogenide (TMD) monolayers and shape programming. I’ll show some recently published results on the influence of strain on microstructure evolution in TMDs and how these influence shape. Next, I’ll explore using TMDs as a vehicle for shape programming, via patterning composition. Conjugately, I’ll also discuss the formation of composition patterns by growing TMDs on non-flat substrates. For concreteness, we focus on the TMD alloy MoSe2cS2(1-c); i.e., MoSeS. These 2D materials down-scale shape/composition programming to nanoscale objects/patterns, provide control of both bending and stretching deformations, are reversibly actuatable with electric fields, and possess the extraordinary and diverse properties of TMDs. Utilizing a first principles-informed continuum model, we demonstrate how a variety of shapes/composition patterns can be programmed and reversibly modulated across length scales. The vast space of possible designs and scales enables novel material properties and thus new applications spanning flexible electronics/optics, catalysis, responsive coatings, and soft robotics.
Narrative Bio:
David Srolovitz is the author of 500 papers on topics in materials theory and simulations ranging from defects (surfaces, grain boundaries, dislocations, point defects), microstructure evolution (grain growth, dislocations, stress effects, phase transformations), deformation (nanomaterials, dislocation motion, creep), and film growth (sputtering, evaporation, CVD) and has an h-index of 92 with more than 30,000 literature citations. He is a Member of the National Academy of Engineering, Fellow of MRS, TMS, ASM, Institute of Physics and is the winner of the MRS Materials Theory Award. Srolovitz did his undergraduate work in Physics at Rutgers University and PhD from the University of Pennsylvania. He was a staff member at Exxon Corporate Research and Los Alamos National Laboratory early in his career and then was professor at the University of Michigan (Materials Science and Applied Physics), Princeton University (Mechanical and Aerospace Engineering, Applied Mathematics), and the University of Pennsylvania (Materials Science, Mechanical Engineering, Institute for Computational Science). He also served as the Executive Director of the Institute of High Performance Computing and the Scientific Director of the Science and Engineering Research Council in Singapore. Srolovitz is now a Chair Professor at the City University of Hong Kong and Senior Fellow of the Hong Kong Institute for Advanced Study.
The properties of 2D materials can be broadly tuned through alloying, phase and strain engineering. I will discuss two topics: the interaction between phase transformations in 2D transition metal dichalcogenide (TMD) monolayers and shape programming. I’ll show some recently published results on the influence of strain on microstructure evolution in TMDs and how these influence shape. Next, I’ll explore using TMDs as a vehicle for shape programming, via patterning composition. Conjugately, I’ll also discuss the formation of composition patterns by growing TMDs on non-flat substrates. For concreteness, we focus on the TMD alloy MoSe2cS2(1-c); i.e., MoSeS. These 2D materials down-scale shape/composition programming to nanoscale objects/patterns, provide control of both bending and stretching deformations, are reversibly actuatable with electric fields, and possess the extraordinary and diverse properties of TMDs. Utilizing a first principles-informed continuum model, we demonstrate how a variety of shapes/composition patterns can be programmed and reversibly modulated across length scales. The vast space of possible designs and scales enables novel material properties and thus new applications spanning flexible electronics/optics, catalysis, responsive coatings, and soft robotics.
Narrative Bio:
David Srolovitz is the author of 500 papers on topics in materials theory and simulations ranging from defects (surfaces, grain boundaries, dislocations, point defects), microstructure evolution (grain growth, dislocations, stress effects, phase transformations), deformation (nanomaterials, dislocation motion, creep), and film growth (sputtering, evaporation, CVD) and has an h-index of 92 with more than 30,000 literature citations. He is a Member of the National Academy of Engineering, Fellow of MRS, TMS, ASM, Institute of Physics and is the winner of the MRS Materials Theory Award. Srolovitz did his undergraduate work in Physics at Rutgers University and PhD from the University of Pennsylvania. He was a staff member at Exxon Corporate Research and Los Alamos National Laboratory early in his career and then was professor at the University of Michigan (Materials Science and Applied Physics), Princeton University (Mechanical and Aerospace Engineering, Applied Mathematics), and the University of Pennsylvania (Materials Science, Mechanical Engineering, Institute for Computational Science). He also served as the Executive Director of the Institute of High Performance Computing and the Scientific Director of the Science and Engineering Research Council in Singapore. Srolovitz is now a Chair Professor at the City University of Hong Kong and Senior Fellow of the Hong Kong Institute for Advanced Study.
