Atomistic Engineering of Colloidal Transition-Metal-Dichalcogenide Quantum Dots

Date

Jul 27, 2026

Time

4:30 PM - 5:30 PM

Speaker

Prof. Caterina Cocchi

Affiliation

Friedrich-Schiller-Universität Jena

Series

MPI-PKS Kolloquium

Language

en

Main Topic

Physik

Other Topics

Physik

Description

Colloidal transition metal dichalcogenide (TMD) quantum dots (QDs) represent highly tunable platforms for next-generation optoelectronic, catalytic, and spintronic applications. However, their functional performance is often dictated by the interplay between quantum confinement and topology, fundamental material characteristics that are hard to identify and disentangle in experiments. In this talk, I will show how ab initio simulations can shed light on the complex phenomena behind exciton quenching and magnetism in TMD QDs. Focusing on hexagonal nanoplatelets as a relevant model of colloidal TMDs, we identify that edge-located, optically bright hole traps are responsible for sub-picosecond exciton decay. These intrinsic trap states, stemming from metal d-orbitals, outcompete radiative recombination in small nanostructures but are simultaneously responsible for enhanced catalytic activity. Next, we investigate the emergence of intrinsic edge magnetism in triangular MoS$_2$ nanoflakes. Our results reveal a critical size threshold of about 1.5 nm, above which a magnetic ground state emerges due to polar discontinuities at the edges. This results in the formation of magnetic islands localized on specific Mo edge atoms, providing discrete, addressable magnetic units rather than delocalized edge spins. By unraveling the fundamental physics of these systems, we establish a rational basis for the design of multifunctional 2D nanomaterials for future technological applications, including spin filters, memory elements, and spin qubits.

Last modified: Jun 22, 2026, 7:40:21 AM