Lee, J.E., Motti, S.G., Oliver, R.D.J. orcid.org/0000-0003-4980-7940 et al. (4 more authors) (2024) Unraveling loss mechanisms arising from energy‐level misalignment between metal halide perovskites and hole transport layers. Advanced Functional Materials, 34 (30). 2401052. ISSN 1616-301X
Abstract
Metal halide perovskites are promising light absorbers for multijunction photovoltaic applications because of their remarkable bandgap tunability, achieved through compositional mixing on the halide site. However, poor energy-level alignment at the interface between wide-bandgap mixed-halide perovskites and charge-extraction layers still causes significant losses in solar-cell performance. Here, the origin of such losses is investigated, focusing on the energy-level misalignment between the valence band maximum and the highest occupied molecular orbital (HOMO) for a commonly employed combination, FA0.83Cs0.17Pb(I1-xBrx)3 with bromide content x ranging from 0 to 1, and poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA). A combination of time-resolved photoluminescence spectroscopy and numerical modeling of charge-carrier dynamics reveals that open-circuit voltage (VOC) losses associated with a rising energy-level misalignment derive from increasing accumulation of holes in the HOMO of PTAA, which then subsequently recombine non-radiatively across the interface via interfacial defects. Simulations assuming an ideal choice of hole-transport material to pair with FA0.83Cs0.17Pb(I1-xBrx)3 show that such VOC losses originating from energy-level misalignment can be reduced by up to 70 mV. These findings highlight the urgent need for tailored charge-extraction materials exhibiting improved energy-level alignment with wide-bandgap mixed-halide perovskites to enable solar cells with improved power conversion efficiencies.
Metadata
Item Type: | Article |
---|---|
Authors/Creators: |
|
Copyright, Publisher and Additional Information: | © 2024 The Authors. Advanced Functional Materials published by Wiley-VCH GmbH This is an open access article under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits use, distribution and reproduction in any medium, provided the original work is properly cited. |
Keywords: | band alignment; charge carrier dynamics; hole transport layers; mixed halide perovskites; open circuit voltage; transient photoluminescence; wide-bandgap |
Dates: |
|
Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Engineering (Sheffield) > Department of Materials Science and Engineering (Sheffield) |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 08 Apr 2024 13:33 |
Last Modified: | 08 Nov 2024 16:35 |
Status: | Published |
Publisher: | Wiley |
Refereed: | Yes |
Identification Number: | 10.1002/adfm.202401052 |
Sustainable Development Goals: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:211262 |