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Probing the Origin of the Open Circuit Voltage in Perovskite Quantum Dot PhotovoltaicsPerovskite quantum dots (PQDs) have many properties that make them attractive for optoelectronic applications, including expanded compositional tunability and crystallographic stabilization. While they have not achieved the same photovoltaic (PV) efficiencies of top-performing perovskite thin films, they do reproducibly show high open circuit voltage (VOC) in comparison. Further understanding of the VOC attainable in PQDs as a function of surface passivation, contact layers, and PQD composition will further progress the field and may lend useful lessons for non-QD perovskite solar cells. Here, we use photoluminescence-based spectroscopic techniques to understand and identify the governing physics of the VOC in CsPbI3 PQDs. In particular, we probe the effect of the ligand exchange and contact interfaces on the VOC and free charge carrier concentration. The free charge carrier concentration is orders of magnitude higher than in typical perovskite thin films and could be tunable through ligand chemistry. Tuning the PQD A-site cation composition via replacement of Cs+ with FA+ maintains the background carrier concentration but reduces the trap density by up to a factor of 40, reducing the VOC deficit. These results dictate how to improve PQD optoelectronic properties and PV device performance and explain the reduced interfacial recombination observed by coupling PQDs with thin-film perovskites for a hybrid absorber layer.
Document ID
20210026682
Acquisition Source
Glenn Research Center
Document Type
Accepted Manuscript (Version with final changes)
Authors
Brian M. Wieliczka
(National Renewable Energy Laboratory Golden, Colorado, United States)
Jose A. Marquez
(Helmholtz-Zentrum Berlin für Materialien und Energie Berlin, Germany)
Alexandra M. Bothwell
(National Renewable Energy Laboratory Golden, Colorado, United States)
Qian Zhao
(National Renewable Energy Laboratory Golden, Colorado, United States)
Taylor Moot
(National Renewable Energy Laboratory Golden, Colorado, United States)
Kaitlyn T. VanSant
(National Renewable Energy Laboratory Cleveland, Ohio, United States)
Andrew J. Ferguson
(National Renewable Energy Laboratory Golden, Colorado, United States)
Thomas Unold
(Helmholtz-Zentrum Berlin für Materialien und Energie Berlin, Germany)
Darius Kuciauskas
(National Renewable Energy Laboratory Golden, Colorado, United States)
Joseph M. Luther
(National Renewable Energy Laboratory Golden, Colorado, United States)
Date Acquired
January 11, 2022
Publication Date
December 3, 2021
Publication Information
Publication: ACS Nano
Publisher: American Chemical Society
Volume: 15
Issue: 12
Issue Publication Date: December 3, 2021
ISSN: 1936-0851
e-ISSN: 1936-086X
URL: https://doi.org/10.1021/acsnano.1c05642
Subject Category
Energy Production And Conversion
Funding Number(s)
WBS: 255421.04.22.20.01
CONTRACT_GRANT: DE-AC36-08GO28308
CONTRACT_GRANT: SURPRISE 423749265
CONTRACT_GRANT: NSF 21576140
CONTRACT_GRANT: EERE 34361
Distribution Limits
Public
Copyright
Use by or on behalf of the US Gov. Permitted.
Technical Review
Professional Review
Keywords
perovskite quantum dot
solar cell
open circuit voltage
quasi-Fermi level splitting
electronic traps
time-resolved photoluminescence
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