CBC Seminar Series presents Dr. Sarah Stoll, Professor of Chemistry at Georgetown University: "Magnetic Lanthanide Polychalcogenides: Growing Nanocrystals in 2-Dimensions.”
12:00 p.m. to 1:00 p.m.
Department of Chemistry and Biochemistry
Presents:
Dr. Sarah Stoll
Professor Of Chemistry, Georgetown University
GP1002: 12pm - 1pm
April 1, 2026
“Magnetic Lanthanide Polychalcogenides: Growing Nanocrystals in 2-Dimensions.”
Inspired by novel magnetic behavior observed in atomically thin 2-dimensional nanosheets, we have synthesized and characterized three classes of lanthanide chalcogenide nanosheets. The first class, the LnTe3 (Ln = lanthanide) are Van der Waals antiferromagnets. Identifying reactive tellurium reagents was key to this synthesis, and solution conditions could be tailored control nanosheet thickness to <10 nm thick. The second class, the LnSe2 materials were prepared using single source precursors: Ln(Se2PPh2)3Phen (Ph = phenyl, Phen = phenanthroline) and trivalent lanthanides (Ln). Because the nanosheets tended to stack, this was an ideal system to investigate growth mechanisms using Transmission Electron Microscopy. Finally, we have developed a synthesis for EuSe2 a metastable, and metamagnetic material with divalent europium. Metamagnetism occurs when materials exhibit antiferromagnetism at low magnetic fields and becomes ferromagnetic at higher fields. This work is the first example in which anisotropic magnetism was demonstrated for nanosheet powders.