IBS 2DQH Seminar

July 08 2024, 4:00 PM
Sungkyunkwan University, Suwon

Generation of Energetic Hot electrons and Superradiance from Strongly Quantum-Confined Lead Halide Perovskite Quantum Dots and Their Superlattices

Dong Hee Son

Department of Chemistry and Department of Physics & Astronomy

Texas A&M University, College Station, TX, USA 

Abstract

Imposing strong quantum confinement in lead halide perovskite nanocrystals enhances the electronic interactions of charge carriers within each nanocrystal and promotes the delocalization of the exciton wavefunction between the nanocrystals in the closely packed quantum dot assemblies. Such enhanced intra- and inter-quantum dot electronic (or exciton) coupling in strong confinement regime can enhance the capability of perovskite quantum dots as the source of hot electrons and coherent photons. Here, we investigated: (i) the generation of hot electrons via Auger hot electron upconversion in strongly quantum-confined cesium lead bromide (CsPbBr₃) nanocrystals doped with Mn²⁺ and (ii) the coherent photon emission as the superradiance from the superlattices of CsPbBr₃ quantum dots. The enhanced exciton-dopant interaction in strongly quantum-confined CsPbBr₃ quantum dots proved beneficial for energetic hot electron generation and allowed for the utilization of the long-lived dark exciton in such processes at low temperatures. The closely-packed QD superlattice CsPbBr₃ quantum dots exhibited coherent photon emission as superradiance significantly better than the larger weakly-confined quantum dots taking advantage of the facilitated exciton delocalization in the superlattices formed from the strongly-confined quantum dots.

Brief Biography

Dr. Son is a professor in the department of chemistry, and department of physics & astronomy at Texas A&M University. He obtained B.S. and M.S degrees from Seoul National University, and Ph.D. degree from University of Texas, Austin. Before joining Texas A&M, Dr. Son did his postdoctoral research at University of California, Berkely. His research focuses on the experimental investigation of the optical, electronic, magnetic and structural properties of various nanocrystalline materials using spectroscopic and microscopic tools with potential applications in photonics, catalysis and quantum information science.