Materials Science Research Lecture

Webinar Link:

https://caltech.zoom.us/j/95708772987

Webinar ID: 957 0877 2987

Abstract:

Single-layer of molybdenum disulfide (MoS2) and other transition metal dichalcogenides (TMDC) appear to be promising materials for next generation optoelectronic applications, because of their low-dimensionality and intrinsic direct band-gap which typically lies in the visible spectrum. MoS2 is also known to be a leading hydrodesulphurization catalyst, for reasons that remain elusive. Another 2D material displaying novel chemical and optical properties is good old hexagonal boron nitride (h-BN). Efforts are underway to further tune these properties through alloying, defects, doping, coupling to a substrate, and formation of bilayer stacks (homo- and hetero-structures). In this talk, I will present some results which provide a framework for manipulating the functionality of these interesting van der Waals materials. With regard to optical properties, I will present our analysis of the quasiparticle energetics (excitons, trions, etc.) and ultrafast charge dynamics in both single- and bi-layer TMDCs obtained through the application of combined time-dependent density functional theory and many-body theory. In the case of defect-laden h-BN, I will present our results for single photon emission for several defect types and their comparison with recent experimental data. With emphasis on the role of defects on single layer MoS2 and h-BN, I will examine modulations of the local atomic environment under which these inert materials could serve as a catalyst for hydrogenation of CO2 and CO. I will also present experimental results that validate our predictions.

More about the Speaker:

Talat Rahman is a Pegasus and Distinguished Professor at University of Central Florida. She received her BS in Physics from University of Karachi and PhD in Physics from University of Rochester. After research appointments (postdoctoral to assistant research physicist) at University of California, Irvine, she served Kansas State University (1983-2006) through the ranks of Assistant Professor to University Distinguished Professor. She joined the University of Central Florida in 2006 as a distinguished professor of Physics and served as the chair of Physics (2006-2015). Her research interests are in computational design of functional nanomaterials through microscopic understanding of their physical and chemical properties. A related interest is in multiscale modeling of chemical reactions and thin film growth processes. At UCF, she has led the effort to transform undergraduate instructions by infusing active learning environments through PER-tested strategies. Her research and education efforts have been funded through grants from the US Department of Energy and the National Science Foundation. She is a fellow of the American Physical Society, Royal Society of Chemistry (UK) and the American Vacuum Society, and recipient of several professional awards including the Research Incentive and Excellence Awards from UCF, Visiting Miller Professorship from University of California-Berkeley, Alexander von Humboldt Research Prize, Higuchi Research Award from the University of Kansas, and the Distinguished Graduate Faculty Award, Kansas State University. She has published about 300 refereed papers, mentored about 30 PhD students, and engaged in promoting scientific collaborations in developing countries. She has been involved in efforts to promote the participation of women and minorities (particularly through the Bridge Program of American Physical Society) in physics and other STEM areas.