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

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3 Citations (Scopus)


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 languageEnglish
Pages (from-to)4981-4987
Number of pages7
JournalJournal of Physical Chemistry Letters
Issue number20
Publication statusPublished - Oct 19 2017


ASJC Scopus subject areas

  • Materials Science(all)
  • Physical and Theoretical Chemistry

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