Title: Synthesis and Spectroscopy of Silver-Doped PbSe Quantum Dots

Abstract

Electronic impurity doping of bulk semiconductors is an essential component of semiconductor science and technology. Yet there are only a handful of studies demonstrating control of electronic impurities in semiconductor nanocrystals. Here, we studied electronic impurity doping of colloidal PbSe quantum dots (QDs) using a postsynthetic cation exchange reaction in which Pb is exchanged for Ag. We found that varying the concentration of dopants exposed to the as-synthesized PbSe QDs controls the extent of exchange. The electronic impurity doped QDs exhibit the fundamental spectroscopic signatures associated with injecting a free charge carrier into a QD under equilibrium conditions, including a bleach of the first exciton transition and the appearance of a quantum-confined, low-energy intraband absorption feature. Photoelectron spectroscopy confirms that Ag acts as a p-type dopant for PbSe QDs and infrared spectroscopy is consistent with k • p calculations of the size-dependent intraband transition energy. We find that to bleach the first exciton transition by an average of 1 carrier per QD requires that approximately 10% of the Pb be replaced by Ag. Here, we hypothesize that the majority of incorporated Ag remains at the QD surface and does not interact with the core electronic states of the QD. Instead,more » the excess Ag at the surface promotes the incorporation of <1% Ag into the QD core where it causes p-type doping behavior.« less

Authors:

Kroupa, Daniel M.  ^[1];

• Search DOE PAGES for author "Kroupa, Daniel M."
• Search DOE PAGES for ORCID "0000-0002-2788-3670"

Hughes, Barbara K. ^[1]; Miller, Elisa M. ^[2]; Moore, David T. ^[2]; Anderson, Nicholas C. ^[2]; Chernomordik, Boris D. ^[2]; Nozik, Arthur J. ^[1]; Beard, Matthew C.  ^[2]

• Search DOE PAGES for author "Beard, Matthew C."
• Search DOE PAGES for ORCID "0000-0002-2711-1355"

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+ Show Author Affiliations

1. National Renewable Energy Lab. (NREL), Golden, CO (United States); Univ. of Colorado, Boulder, CO (United States)
2. National Renewable Energy Lab. (NREL), Golden, CO (United States)

Publication Date:

Sun Jun 25 00:00:00 EDT 2017

Research Org.:

National Renewable Energy Laboratory (NREL), Golden, CO (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1374971

Report Number(s):

NREL/JA-5900-67594
Journal ID: ISSN 0002-7863; TRN: US1702347

Grant/Contract Number:  

AC36-08GO28308

Resource Type:

Accepted Manuscript

Journal Name:

Journal of the American Chemical Society

Additional Journal Information:

Journal Volume: 139; Journal Issue: 30; Journal ID: ISSN 0002-7863

Publisher:

American Chemical Society (ACS)

Country of Publication:

United States

Language:

English

Subject:

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; quantum dots; doping; PbSe