Ph.D. Candidate, McMaster University
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“Predicting opto-electronic properties of next-generation 2D materials”
Nanomaterials with properties on demand are of significant interest for the design of next-generation photonic and electronic devices. In recent years, a bounty of new 2D materials has been proposed. For the successful integration of these 2D materials into photonic and electronic applications, it is crucial to first explore how to modify their properties. Thus, the understanding of structure-property relationships creates pathways to help control relevant properties of materials and so design materials on demand.
Our research aims at accelerating the design of 2D materials using predictive modelling. In this talk, I will present results obtained from first-principles calculations at the density functional theory level and with many-body theory. First, I will talk about the effect of pressure on the direct band gap of layered ReS2 and ReSe2: Analysis of the response of the electronic band structure to pressure allows further insight to clarify the nature of the interaction between adjacent layers. Our calculations illuminate the cause of an unexpected shift of the band gap with pressure observed experimentally. Second, I will focus on dark excitons, i.e. forbidden optical transitions, in monolayer MoS2. When considering the exciton binding effect, the band structure undergoes changes causing the lowest-energy direct transition to be dark.
I will conclude my talk by showing how our results give guidance in the search for suitable materials for opto-electronic applications by providing a deeper understanding of the structure-property relationships in 2D materials.
Magdalena Laurien, Ph.D. Candidate, McMaster University
Magdalena Laurien is a fourth-year graduate student in materials science and engineering at McMaster University with an expected graduation in Fall 2021. Prior to starting her graduate studies, she received her M.Sc. in materials science and production engineering from the University of Bremen, Germany. Her master’s thesis on polymer interfaces was awarded the Outstanding Thesis Award by the Bremer Unifreunde e.V.. Magdalena is currently working under the supervision of Dr. Oleg Rubel, focusing on predicting the opto-electronic properties of two-dimensional (2D) semiconductors with first-principles methods. She has contributed to solving two problems: modelling of indirect excitonic states in 2D molybdenum disulphide and pressure dependence of optical transitions in rhenium disulphide and rhenium diselenide. Magdalena is passionate about material structure-property-processing relationships and is interested in multi-scale modelling with the goal of accelerating the experimental synthesis of 2D materials. In 2019, she taught an undergraduate course on materials science at McMaster. Since 2018, Magdalena has been involved in the community of international graduate students at McMaster.