TY - JOUR
T1 - Reversible Modulation of the Electrostatic Potential of a Colloidal Quantum Dot through the Protonation Equilibrium of Its Ligands
AU - He, Chen
AU - Zhang, Zhengyi
AU - Wang, Chen
AU - Jiang, Yishu
AU - Weiss, Emily A.
N1 - Funding Information:
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.
Publisher Copyright:
© 2017 American Chemical Society.
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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U2 - 10.1021/acs.jpclett.7b02101
DO - 10.1021/acs.jpclett.7b02101
M3 - Article
C2 - 28949145
AN - SCOPUS:85031805502
SN - 1948-7185
VL - 8
SP - 4981
EP - 4987
JO - Journal of Physical Chemistry Letters
JF - Journal of Physical Chemistry Letters
IS - 20
ER -