TY - JOUR
T1 - Mechanisms of Defect Passivation by Fluorinated Alkylthiolates on PbS Quantum Dots
AU - Perez, Kaitlyn A.
AU - Lian, Shichen
AU - Kodaimati, Mohamad S.
AU - He, Chen
AU - Weiss, Emily A.
N1 - Funding Information:
K.A.P. was supported by the Department of Defense (DoD) through the National Defense Science & Engineering Graduate Fellowship (NDSEG) Program. Materials and instrument time were funded through the NU Materials Research Science and Engineering Center (NSF DMR-1720139). This work made use of the IMSERC at Northwestern University, which has received support from the NIH (1S10OD012016-01/ 1S10RR019071-01A1); Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205); the State of Illinois and International Institute for Nanotechnology (IIN). Metal analysis was performed at the Northwestern University Quantitative Bioelement Imaging Center. This work made use of the EPIC facility of Northwestern University’s NUANCE Center, which has received support from SHyNE; the MRSEC program (NSF DMR-1720139) at the Materials Research Center; the IIN; the Keck Foundation; and the State of Illinois, through the IIN. This work utilized the Northwestern University Micro/Nano Fabrication Facility (NUFAB), which is partially supported by SHyNE, MRSEC, the State of Illinois, and Northwestern University. We thank Rebecca Sponenburg and Dr. Keith MacRenaris for their help with inductively coupled plasma optical emission spectrometry.
Publisher Copyright:
© 2018 American Chemical Society.
PY - 2018/6/28
Y1 - 2018/6/28
N2 - Defects in the organic ligand layers on the surfaces of colloidal quantum dots (QDs) provide pathways for corrosive molecules to penetrate to the QD core. This paper describes the decrease in the permeability of the ligand shells of colloidal near-infrared-emitting PbS QDs to the molecular photo-oxidant, duroquinone (Me4BQ), upon substituting a small fraction of their oleate ligands with either 1-dodecanethiolate (DDT) or progressively fluorinated DDT analogues (with between 1 and 10 fluorinated carbons), as measured by the yield of collisionally gated photoinduced electron transfer from the QD to Me4BQ. The permeabilities of mixed-monolayer ligand shells of oleate and 8-16% (by surface area) DDT are 35-41% lower than those of the pure oleate monolayers. Increasing the number of fluorinated carbons in the thiolate ligands from 0 to 10 results in an additional 40-66% decrease in the permeability of the ligand shell; as few as 0.05% of collisions between the largest QDs and Me4BQ result in electron transfer. The thiolate exchange, and fluorination of the thiolate ligands, more effectively protect the largest QDs than the smallest QDs, primarily due to the size-dependence of the types of defects in the native oleate monolayers.
AB - Defects in the organic ligand layers on the surfaces of colloidal quantum dots (QDs) provide pathways for corrosive molecules to penetrate to the QD core. This paper describes the decrease in the permeability of the ligand shells of colloidal near-infrared-emitting PbS QDs to the molecular photo-oxidant, duroquinone (Me4BQ), upon substituting a small fraction of their oleate ligands with either 1-dodecanethiolate (DDT) or progressively fluorinated DDT analogues (with between 1 and 10 fluorinated carbons), as measured by the yield of collisionally gated photoinduced electron transfer from the QD to Me4BQ. The permeabilities of mixed-monolayer ligand shells of oleate and 8-16% (by surface area) DDT are 35-41% lower than those of the pure oleate monolayers. Increasing the number of fluorinated carbons in the thiolate ligands from 0 to 10 results in an additional 40-66% decrease in the permeability of the ligand shell; as few as 0.05% of collisions between the largest QDs and Me4BQ result in electron transfer. The thiolate exchange, and fluorination of the thiolate ligands, more effectively protect the largest QDs than the smallest QDs, primarily due to the size-dependence of the types of defects in the native oleate monolayers.
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U2 - 10.1021/acs.jpcc.8b01066
DO - 10.1021/acs.jpcc.8b01066
M3 - Article
AN - SCOPUS:85049412929
SN - 1932-7447
VL - 122
SP - 13911
EP - 13919
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
IS - 25
ER -