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Title: Intrinsic Exciton Photophysics of PbS Quantum Dots Revealed by Low-Temperature Single Nanocrystal Spectroscopy

Abstract

With a tunable size-dependent photoluminescence (PL) over a wide infrared wavelength range, lead chalcogenide quantum dots (QDs) have attracted significant scientific and technological interest. Nevertheless, the investigation of intrinsic exciton photophysics at the single-QD level has remained a challenge. Herein, we present a comprehensive study of PL properties for the individual core/shell PbS/CdS QDs emissive near 1.0 eV. In contrast to the sub-meV spectral line widths observed for II/VI QDs, PbS/CdS QDs are predicted to possess broad homogeneous line widths. Performing spectroscopy at cryogenic (4 K) temperatures, we provide direct evidence confirming theoretical predictions, showing that intrinsic line widths for PbS/CdS QDs are in the range of 8–25 meV, with an average of 16.4 meV. In addition, low-temperature, single-QD spectroscopy reveals a broad low-energy side emission attributable to optical as well as localized acoustic phonon-assisted transitions. By tracking single QDs from 4 to 250 K, we were able to probe temperature-dependent evolutions of emission energy, line width, and line shape. Lastly, polarization-resolved PL imaging showed that PbS/CdS QDs are characterized by a 3D emission dipole, in contrast with the 2D dipole observed for CdSe QDs.

Authors:
ORCiD logo [1];  [1];  [2];  [3]; ORCiD logo [3]; ORCiD logo [1]; ORCiD logo [4]; ORCiD logo [5]; ORCiD logo [1]; ORCiD logo [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States); The Univ. of Texas at Dallas, Richardson, TX (United States)
  3. Ioffe Inst., St. Petersburg (Russia)
  4. The Univ. of Texas at Dallas, Richardson, TX (United States)
  5. Ioffe Inst., St. Petersburg (Russia); Jackson State Univ., Jackson, MS (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division
OSTI Identifier:
1579703
Report Number(s):
LA-UR-19-29763
Journal ID: ISSN 1530-6984
Grant/Contract Number:  
89233218CNA000001; SC0010697; HRD-154775
Resource Type:
Accepted Manuscript
Journal Name:
Nano Letters
Additional Journal Information:
Journal Volume: 19; Journal Issue: 12; Journal ID: ISSN 1530-6984
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; material science; infrared nanocrystals; PbS/CdS; single nanocrystal spectroscopy; spectral linewidth; bandgap; polarization

Citation Formats

Hu, Zhongjian, Kim, Younghee, Krishnamurthy, Sachidananda, Avdeev, Ivan D., Nestoklon, Mikhail O., Singh, Ajay, Malko, Anton V., Goupalov, Serguei V., Hollingsworth, Jennifer Ann, and Htoon, Han. Intrinsic Exciton Photophysics of PbS Quantum Dots Revealed by Low-Temperature Single Nanocrystal Spectroscopy. United States: N. p., 2019. Web. doi:10.1021/acs.nanolett.9b02937.
Hu, Zhongjian, Kim, Younghee, Krishnamurthy, Sachidananda, Avdeev, Ivan D., Nestoklon, Mikhail O., Singh, Ajay, Malko, Anton V., Goupalov, Serguei V., Hollingsworth, Jennifer Ann, & Htoon, Han. Intrinsic Exciton Photophysics of PbS Quantum Dots Revealed by Low-Temperature Single Nanocrystal Spectroscopy. United States. doi:10.1021/acs.nanolett.9b02937.
Hu, Zhongjian, Kim, Younghee, Krishnamurthy, Sachidananda, Avdeev, Ivan D., Nestoklon, Mikhail O., Singh, Ajay, Malko, Anton V., Goupalov, Serguei V., Hollingsworth, Jennifer Ann, and Htoon, Han. Tue . "Intrinsic Exciton Photophysics of PbS Quantum Dots Revealed by Low-Temperature Single Nanocrystal Spectroscopy". United States. doi:10.1021/acs.nanolett.9b02937.
@article{osti_1579703,
title = {Intrinsic Exciton Photophysics of PbS Quantum Dots Revealed by Low-Temperature Single Nanocrystal Spectroscopy},
author = {Hu, Zhongjian and Kim, Younghee and Krishnamurthy, Sachidananda and Avdeev, Ivan D. and Nestoklon, Mikhail O. and Singh, Ajay and Malko, Anton V. and Goupalov, Serguei V. and Hollingsworth, Jennifer Ann and Htoon, Han},
abstractNote = {With a tunable size-dependent photoluminescence (PL) over a wide infrared wavelength range, lead chalcogenide quantum dots (QDs) have attracted significant scientific and technological interest. Nevertheless, the investigation of intrinsic exciton photophysics at the single-QD level has remained a challenge. Herein, we present a comprehensive study of PL properties for the individual core/shell PbS/CdS QDs emissive near 1.0 eV. In contrast to the sub-meV spectral line widths observed for II/VI QDs, PbS/CdS QDs are predicted to possess broad homogeneous line widths. Performing spectroscopy at cryogenic (4 K) temperatures, we provide direct evidence confirming theoretical predictions, showing that intrinsic line widths for PbS/CdS QDs are in the range of 8–25 meV, with an average of 16.4 meV. In addition, low-temperature, single-QD spectroscopy reveals a broad low-energy side emission attributable to optical as well as localized acoustic phonon-assisted transitions. By tracking single QDs from 4 to 250 K, we were able to probe temperature-dependent evolutions of emission energy, line width, and line shape. Lastly, polarization-resolved PL imaging showed that PbS/CdS QDs are characterized by a 3D emission dipole, in contrast with the 2D dipole observed for CdSe QDs.},
doi = {10.1021/acs.nanolett.9b02937},
journal = {Nano Letters},
number = 12,
volume = 19,
place = {United States},
year = {2019},
month = {11}
}

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