Elucidating the origin of external quantum efficiency losses in cuprous oxide solar cells through defect analysis
File(s)
Accepted version
Author(s)
Type
Journal Article
Abstract
Heterojunction Cu2O solar cells are an important class of earth-abundant photovoltaics that can be synthesized by a variety of techniques, including electrochemical deposition (ECD) and thermal oxidation (TO). The latter gives the most efficient solar cells of up to 8.1 %, but is limited by low external quantum efficiencies (EQE) in the long wavelength region. By contrast, ECD Cu2O gives higher short wavelength EQEs of up to 90 %. We elucidate the cause of this difference by characterizing and comparing ECD and TO films using impedance spectroscopy and fitting with a lumped circuit model to determine the trap density, followed by simulations. The data indicates that TO Cu2O has a higher density of interface defects, located approximately 0.5 eV above the valence band maximum (NV),and lower bulk defect density thus explaining the lower short wavelength EQEs and higher long wavelength EQEs. This work shows that a route to further efficiency increases of TO Cu2O is to reduce the density of interface defect states.
Date Issued
2020-06-01
Date Acceptance
2020-01-15
Citation
Solar Energy Materials and Solar Cells, 2020, 209, pp.1-8
ISSN
0165-1633
Publisher
Elsevier
Start Page
1
End Page
8
Journal / Book Title
Solar Energy Materials and Solar Cells
Volume
209
Copyright Statement
© 2020 Elsevier Ltd. All rights reserved. This manuscript is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International Licence http://creativecommons.org/licenses/by-nc-nd/4.0/
Identifier
https://www.sciencedirect.com/science/article/pii/S0927024820300258?via%3Dihub
Subjects
02 Physical Sciences
03 Chemical Sciences
09 Engineering
Energy
Publication Status
Published
Date Publish Online
2020-03-04