Reversible Modulation of the Electrostatic Potential of a Colloidal Quantum Dot through the Protonation Equilibrium of Its Ligands

Chen He; Zhengyi Zhang; Chen Wang; Yishu Jiang; Emily A. Weiss

doi:10.1021/acs.jpclett.7b02101

Reversible Modulation of the Electrostatic Potential of a Colloidal Quantum Dot through the Protonation Equilibrium of Its Ligands

Chen He, Zhengyi Zhang, Chen Wang, Yishu Jiang, Emily A. Weiss^*

^*Corresponding author for this work

Chemistry

Research output: Contribution to journal › Article › peer-review

6 Scopus citations

Abstract

This Letter describes the reversible modulation of the electrostatic potential at the interface between a colloidal PbS quantum dot (QD) and solvent, through the protonation equilibrium of the QD's histamine-derivatized dihydrolipoic acid (DHLA) ligand shell. The electrostatic potential is sensitively monitored by the yield of photoinduced electron transfer from the QD to a charged electron acceptor, 9,10-anthraquinone-2-sulfonate (AQ). The permeability of the DHLA coating to the AQ progressively increases as the average degree of protonation of the ligand shell increases from 0 to 92%, as quantified by ¹H NMR, upon successive additions of p-toluenesulfonic acid; this increase results in a decrease in the photoluminescence (PL) intensity of the QDs by a factor of 6.7. The increase in permeability is attributable to favorable electrostatic interactions between the ligands and AQ. This work suggests the potential of the combination of near-IR-emitting QDs and molecular quenchers as robust local H⁺ sensors.

Original language	English (US)
Pages (from-to)	4981-4987
Number of pages	7
Journal	Journal of Physical Chemistry Letters
Volume	8
Issue number	20
DOIs	https://doi.org/10.1021/acs.jpclett.7b02101
State	Published - Oct 19 2017

Funding

This work was primarily supported by the National Science Foundation under Award #1400596 (synthesis, NMR, and steady-state optical studies) and by the Center for Bio-Inspired Energy Science, an Energy Frontier Research Center funded by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences (BES), under Award #DE-SC0000989 (time-resolved spectroscopy). This work made use of the IMSERC at Northwestern University, which has received support from the NIH (1S10OD012016-01/1S10RR019071-01A1); the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF NNCI-1542205); the State of Illinois; and the International Institute for Nanotechnology (IIN). The authors thank Prof. Andrew Lee, Prof. Regan Thomson, James Hudson Tryon, Dana Westmoreland, and Shichen Lian for useful discussions.

ASJC Scopus subject areas

General Materials Science
Physical and Theoretical Chemistry

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title = "Reversible Modulation of the Electrostatic Potential of a Colloidal Quantum Dot through the Protonation Equilibrium of Its Ligands",

abstract = "This Letter describes the reversible modulation of the electrostatic potential at the interface between a colloidal PbS quantum dot (QD) and solvent, through the protonation equilibrium of the QD's histamine-derivatized dihydrolipoic acid (DHLA) ligand shell. The electrostatic potential is sensitively monitored by the yield of photoinduced electron transfer from the QD to a charged electron acceptor, 9,10-anthraquinone-2-sulfonate (AQ). The permeability of the DHLA coating to the AQ progressively increases as the average degree of protonation of the ligand shell increases from 0 to 92%, as quantified by 1H NMR, upon successive additions of p-toluenesulfonic acid; this increase results in a decrease in the photoluminescence (PL) intensity of the QDs by a factor of 6.7. The increase in permeability is attributable to favorable electrostatic interactions between the ligands and AQ. This work suggests the potential of the combination of near-IR-emitting QDs and molecular quenchers as robust local H+ sensors.",

author = "Chen He and Zhengyi Zhang and Chen Wang and Yishu Jiang and Weiss, {Emily A.}",

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AU - He, Chen

AU - Zhang, Zhengyi

AU - Wang, Chen

AU - Jiang, Yishu

AU - Weiss, Emily A.

PY - 2017/10/19

Y1 - 2017/10/19

N2 - This Letter describes the reversible modulation of the electrostatic potential at the interface between a colloidal PbS quantum dot (QD) and solvent, through the protonation equilibrium of the QD's histamine-derivatized dihydrolipoic acid (DHLA) ligand shell. The electrostatic potential is sensitively monitored by the yield of photoinduced electron transfer from the QD to a charged electron acceptor, 9,10-anthraquinone-2-sulfonate (AQ). The permeability of the DHLA coating to the AQ progressively increases as the average degree of protonation of the ligand shell increases from 0 to 92%, as quantified by 1H NMR, upon successive additions of p-toluenesulfonic acid; this increase results in a decrease in the photoluminescence (PL) intensity of the QDs by a factor of 6.7. The increase in permeability is attributable to favorable electrostatic interactions between the ligands and AQ. This work suggests the potential of the combination of near-IR-emitting QDs and molecular quenchers as robust local H+ sensors.

AB - This Letter describes the reversible modulation of the electrostatic potential at the interface between a colloidal PbS quantum dot (QD) and solvent, through the protonation equilibrium of the QD's histamine-derivatized dihydrolipoic acid (DHLA) ligand shell. The electrostatic potential is sensitively monitored by the yield of photoinduced electron transfer from the QD to a charged electron acceptor, 9,10-anthraquinone-2-sulfonate (AQ). The permeability of the DHLA coating to the AQ progressively increases as the average degree of protonation of the ligand shell increases from 0 to 92%, as quantified by 1H NMR, upon successive additions of p-toluenesulfonic acid; this increase results in a decrease in the photoluminescence (PL) intensity of the QDs by a factor of 6.7. The increase in permeability is attributable to favorable electrostatic interactions between the ligands and AQ. This work suggests the potential of the combination of near-IR-emitting QDs and molecular quenchers as robust local H+ sensors.

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Reversible Modulation of the Electrostatic Potential of a Colloidal Quantum Dot through the Protonation Equilibrium of Its Ligands

Abstract

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