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Sequentially N-Doped Acceptor Primer Layer Facilitates Electron Collection of Inverted Non-Fullerene Organic Solar Cells

Xie, Jiaqi ; Lin, Weihua LU ; Wang, Dengke ; Lu, Zheng Hong ; Zheng, Kaibo LU and Liang, Ziqi (2023) In Advanced Functional Materials
Abstract

In most non-fullerene organic solar cells comprising bulk-heterojunction active layers, the inter-domain connectivity of small-molecule acceptors is generally inferior to those of polymeric donors due to their intrinsic short-range ordering. This issue is even exacerbated by the physiochemical mismatch between acceptor-phases and metal-oxide electron transport layers in most inverted n-i-p devices, leading to inefficient electron collection. By pre-depositing an ultra-thin acceptor primer layer, it develops a novel acceptor-enriched-bottom active layer to reinforce the acceptor-phase continuity. It is however challenging to preserve the primer layer during non-orthogonal solvent processing. Thus, sequential n-type doping is implemented... (More)

In most non-fullerene organic solar cells comprising bulk-heterojunction active layers, the inter-domain connectivity of small-molecule acceptors is generally inferior to those of polymeric donors due to their intrinsic short-range ordering. This issue is even exacerbated by the physiochemical mismatch between acceptor-phases and metal-oxide electron transport layers in most inverted n-i-p devices, leading to inefficient electron collection. By pre-depositing an ultra-thin acceptor primer layer, it develops a novel acceptor-enriched-bottom active layer to reinforce the acceptor-phase continuity. It is however challenging to preserve the primer layer during non-orthogonal solvent processing. Thus, sequential n-type doping is implemented on the surface of the primer layer, which allows to slightly reduce the acceptor solubility by polarity regulation, as well as stabilize the film structure via strong π–π interaction between dopant/host acceptor. Upon acceptor enrichment, higher interfacial electron density enhances the built-in potential while the enlarged domains suppress both charge-transfer state and bimolecular recombination. Consequently, the champion device efficiency is greatly improved from ca. 16.1% to 18.0%, mainly resulting from the simultaneously elevated fill factor and short-circuit current density.

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author
; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
epub
subject
keywords
charge collection, inverted organic solar cells, n-doping, nonfullerene acceptor, prime layer
in
Advanced Functional Materials
publisher
Wiley-Blackwell
external identifiers
  • scopus:85177209208
ISSN
1616-301X
DOI
10.1002/adfm.202309511
language
English
LU publication?
yes
additional info
Publisher Copyright: © 2023 Wiley-VCH GmbH.
id
7b10f097-1ccb-40e3-bd65-175e5899733c
date added to LUP
2024-01-10 12:35:18
date last changed
2024-01-10 13:35:28
@article{7b10f097-1ccb-40e3-bd65-175e5899733c,
  abstract     = {{<p>In most non-fullerene organic solar cells comprising bulk-heterojunction active layers, the inter-domain connectivity of small-molecule acceptors is generally inferior to those of polymeric donors due to their intrinsic short-range ordering. This issue is even exacerbated by the physiochemical mismatch between acceptor-phases and metal-oxide electron transport layers in most inverted n-i-p devices, leading to inefficient electron collection. By pre-depositing an ultra-thin acceptor primer layer, it develops a novel acceptor-enriched-bottom active layer to reinforce the acceptor-phase continuity. It is however challenging to preserve the primer layer during non-orthogonal solvent processing. Thus, sequential n-type doping is implemented on the surface of the primer layer, which allows to slightly reduce the acceptor solubility by polarity regulation, as well as stabilize the film structure via strong π–π interaction between dopant/host acceptor. Upon acceptor enrichment, higher interfacial electron density enhances the built-in potential while the enlarged domains suppress both charge-transfer state and bimolecular recombination. Consequently, the champion device efficiency is greatly improved from ca. 16.1% to 18.0%, mainly resulting from the simultaneously elevated fill factor and short-circuit current density.</p>}},
  author       = {{Xie, Jiaqi and Lin, Weihua and Wang, Dengke and Lu, Zheng Hong and Zheng, Kaibo and Liang, Ziqi}},
  issn         = {{1616-301X}},
  keywords     = {{charge collection; inverted organic solar cells; n-doping; nonfullerene acceptor; prime layer}},
  language     = {{eng}},
  publisher    = {{Wiley-Blackwell}},
  series       = {{Advanced Functional Materials}},
  title        = {{Sequentially N-Doped Acceptor Primer Layer Facilitates Electron Collection of Inverted Non-Fullerene Organic Solar Cells}},
  url          = {{http://dx.doi.org/10.1002/adfm.202309511}},
  doi          = {{10.1002/adfm.202309511}},
  year         = {{2023}},
}