Magnetooptical Studies of Colloidal CdSe Nanoplatelets

Abstract

Magnetooptical Studies of Colloidal CdSe NanoplateletsElena Shornikova aa TU Dortmund University, D-44221 Dortmund, GermanyMaterials for Sustainable Development Conference (MATSUS)Proceedings of MATSUS Spring 2024 Conference (MATSUS24)#Sol2D - Solution-Processed 2D MaterialsBarcelona, Spain, 2024 March 4th - 8thOrganizers: Celso de Mello Donega and Jannika LauthInvited Speaker, Elena Shornikova, presentation 452DOI: https://doi.org/10.29363/nanoge.matsus.2024.452Publication date: 18th December 2023Optical studies of colloidal CdSe nanoplatelets at cryogenic temperatures (typically 1.7–4 K) and in high magnetic fields (typically above 10 T) provide valuable information about their emission properties. Importantly, magnetooptics allows for distinguishing the emission from excitons and trions (charged excitons). These particles have very different photoluminescence kinetics, additionally, their emission lifetimes are affected differently by magnetic fields and temperatures [1]. The exciton fine structure can be visualized by time-resolved polarized photoluminescence and fluorescence line narrowing, and exciton binding energy can be obtained by measuring one- and two-photon absorption [2]. The trion charge, positive or negative, can be identified by studying the photoluminescence polarization in magnetic fields [1]. Interestingly, the surface spins in CdSe nanoplatelets at cryogenic temperatures can be detected by optical techniques [3]. In applied magnetic field, the surface spins orientation results in large Zeeman splitting for the exciton interacting with these spins, similar to the known effect of the giant Zeeman splitting in diluted magnetic semiconductors, like (Cd,Mn)Se. The circular polarization degree about 50% in a magnetic field of 3 T is observed in bare CdSe nanoplatelets. References:[1] Shornikova, E.V. et al. Negatively Charged Excitons in CdSe Nanoplatelets. Nano Lett. 2020, 20, 1370.[2] Shornikova, E.V. et al. Exciton Binding Energy in CdSe Nanoplatelets Measured by One- and Two-Photon Absorption. Nano Lett. 2021, 21, 10525.[3] Shornikova, E.V. et al. Surface Spin Magnetism Controls the Polarized Exciton Emission from CdSe Nanoplatelets. Nat. Nanotech. 2020, 15, 277.Acknowledgements:Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) - project No.: 462009643 © FUNDACIO DE LA COMUNITAT VALENCIANA SCITOnanoGe is a prestigious brand of successful science conferences that are developed along the year in different areas of the world since 2009. 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