Epitaxial Dimers and Auger-Assisted Detrapping in PbS Quantum Dot Solids
Name
combined manuscript file v190319.pdf
Description
Submitted version
Size
3.74 MB
Format
Adobe PDF
Checksum (MD5)
5575b16ca7143732ee9f0275059d1581
Author(s)
Gilmore, Rachel Hoffman
Liu, Yun
Shcherbakov-Wu, Wenbi
Dahod, Nabeel S.
Lee, Elizabeth M.
Weidman, Mark Clayton
Li, Huashan
Jean, Joel
Bulovic, Vladimir
Willard, Adam P.
Date Issued
July 2019
Journal
Matter
Publisher
Elsevier BV
Citation
Gilmore, Rachel H. et al. "Epitaxial Dimers and Auger-Assisted Detrapping in PbS Quantum Dot Solids." Matter 1, 1 (July 2019): P250-265 © 2019 Elsevier Inc
Version
Original manuscript
Abstract
We explore the dynamic interaction of charge carriers between band-edge states and sub-band trap states in PbS quantum dot (QD) solids using time-resolved spectroscopy. In monodisperse arrays of 4- to 5-nm diameter PbS QDs, we observe an optically active trap state ∼100–200 meV below the band edge that occurs at a frequency of 1 in ∼2,500 QDs. Uncoupled QD solids with oleic acid ligands show trap-to-ground-state recombination that resembles Auger recombination. In electronically coupled QD solids, we observe entropically driven uphill thermalization of trapped charge carriers from the trap state to the band edge via two distinct mechanisms: Auger-assisted charge transfer (∼35 ps) and thermally activated hopping (∼500 ps). Photophysical characterization combined with atomistic simulations and high-resolution electron microscopy suggest that these states arise from epitaxially fused pairs of QDs rather than electron or hole traps at the QD surface, offering new strategies for improving the optoelectronic performance of QD materials.
MIT Department
Massachusetts Institute of Technology. Department of Chemical Engineering
Massachusetts Institute of Technology. Department of Materials Science and Engineering
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
Massachusetts Institute of Technology. Department of Chemistry
Massachusetts Institute of Technology. Research Laboratory of Electronics
Terms of Use
Creative Commons Attribution-NonCommercial-NoDerivs License
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1016/j.matt.2019.05.015
