skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Organic-to-Aqueous Phase Transfer of Cadmium Chalcogenide Quantum Dots Using a Sulfur-Free Ligand for Enhanced Photoluminescence and Oxidative Stability

Abstract

This article describes a procedure for transferring colloidal CdS and CdSe quantum dots (QDs) from organic solvents to water by exchanging their native hydrophobic ligands for phosphonopropionic acid (PPA) ligands, which bind to the QD surface through the phosphonate group. This method, which uses dimethylformamide as an intermediate transfer solvent, was developed in order to produce high-quality water soluble QDs with neither a sulfur-containing ligand nor a polymer encapsulation layer, both of which have disadvantages in applications of QDs to photocatalysis and biological imaging. CdS (CdSe) QDs were transferred to water with a 43% (48%) yield using PPA. The photoluminescence (PL) quantum yield for PPA-capped CdSe QDs is larger than that for QDs capped with the analogous sulfur-containing ligand, mercaptopropionic acid (MPA), by a factor of four at pH 7, and by up to a factor of 100 under basic conditions. The MPA ligands within MPA-capped QDs oxidize at E ox ~ +1.7 V vs. SCE, whereas cyclic voltammograms of PPA-capped QDs show no discerible oxidation peaks at applied potentials up to +2.5 V vs. SCE. The PPA-capped QDs are chemically and colloidally stable for at least five days in the dark, even in the presence of O 2, andmore » are stable when continuously illuminated for five days, when oxygen is excluded and a sacrificial reductant is present to capture photogenerated holes.« less

Authors:
 [1];  [1];  [1];  [1];  [1]
  1. Northwestern Univ., Evanston, IL (United States). Dept. of Chemistry
Publication Date:
Research Org.:
Energy Frontier Research Centers (EFRC) (United States). Argonne-Northwestern Solar Energy Research Center (ANSER)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Science Foundation (NSF); National Institutes of Health (NIH)
OSTI Identifier:
1388169
Grant/Contract Number:  
SC0001059
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Chemistry of Materials
Additional Journal Information:
Journal Volume: 28; Journal Issue: 18; Related Information: ANSER partners with Northwestern University (lead); Argonne National Laboratory; University of Chicago; University of Illinois, Urbana-Champaign; Yale University; Journal ID: ISSN 0897-4756
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE

Citation Formats

Calzada, Raul, Thompson, Christopher M., Westmoreland, Dana E., Edme, Kedy, and Weiss, Emily A. Organic-to-Aqueous Phase Transfer of Cadmium Chalcogenide Quantum Dots Using a Sulfur-Free Ligand for Enhanced Photoluminescence and Oxidative Stability. United States: N. p., 2016. Web. doi:10.1021/acs.chemmater.6b03106.
Calzada, Raul, Thompson, Christopher M., Westmoreland, Dana E., Edme, Kedy, & Weiss, Emily A. Organic-to-Aqueous Phase Transfer of Cadmium Chalcogenide Quantum Dots Using a Sulfur-Free Ligand for Enhanced Photoluminescence and Oxidative Stability. United States. doi:10.1021/acs.chemmater.6b03106.
Calzada, Raul, Thompson, Christopher M., Westmoreland, Dana E., Edme, Kedy, and Weiss, Emily A. Fri . "Organic-to-Aqueous Phase Transfer of Cadmium Chalcogenide Quantum Dots Using a Sulfur-Free Ligand for Enhanced Photoluminescence and Oxidative Stability". United States. doi:10.1021/acs.chemmater.6b03106. https://www.osti.gov/servlets/purl/1388169.
@article{osti_1388169,
title = {Organic-to-Aqueous Phase Transfer of Cadmium Chalcogenide Quantum Dots Using a Sulfur-Free Ligand for Enhanced Photoluminescence and Oxidative Stability},
author = {Calzada, Raul and Thompson, Christopher M. and Westmoreland, Dana E. and Edme, Kedy and Weiss, Emily A.},
abstractNote = {This article describes a procedure for transferring colloidal CdS and CdSe quantum dots (QDs) from organic solvents to water by exchanging their native hydrophobic ligands for phosphonopropionic acid (PPA) ligands, which bind to the QD surface through the phosphonate group. This method, which uses dimethylformamide as an intermediate transfer solvent, was developed in order to produce high-quality water soluble QDs with neither a sulfur-containing ligand nor a polymer encapsulation layer, both of which have disadvantages in applications of QDs to photocatalysis and biological imaging. CdS (CdSe) QDs were transferred to water with a 43% (48%) yield using PPA. The photoluminescence (PL) quantum yield for PPA-capped CdSe QDs is larger than that for QDs capped with the analogous sulfur-containing ligand, mercaptopropionic acid (MPA), by a factor of four at pH 7, and by up to a factor of 100 under basic conditions. The MPA ligands within MPA-capped QDs oxidize at Eox ~ +1.7 V vs. SCE, whereas cyclic voltammograms of PPA-capped QDs show no discerible oxidation peaks at applied potentials up to +2.5 V vs. SCE. The PPA-capped QDs are chemically and colloidally stable for at least five days in the dark, even in the presence of O2, and are stable when continuously illuminated for five days, when oxygen is excluded and a sacrificial reductant is present to capture photogenerated holes.},
doi = {10.1021/acs.chemmater.6b03106},
journal = {Chemistry of Materials},
number = 18,
volume = 28,
place = {United States},
year = {Fri Aug 26 00:00:00 EDT 2016},
month = {Fri Aug 26 00:00:00 EDT 2016}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 5 works
Citation information provided by
Web of Science

Save / Share: