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Developing Halogen-Free Polymer Donors for Efficient Nonfullerene Organic Solar Cells by Addition of Highly Electron-Deficient Diketopyrrolopyrrole Unit

Ji, Jingjing ; Xie, Jiaqi ; Tang, Junhui ; Zheng, Kaibo LU and Liang, Ziqi (2021) In Solar RRL 5(5).
Abstract

High-performance polymer donors when paired with nonfullerene acceptors are mainly limited to flanking halogenated benzodithiophene (BDT)-based π-conjugated copolymers, which however involve complex synthetic procedures. Herein, a series of halogen-free polymer donors that link BDT moiety with two highly electron-deficient benzodithiophene-dione (BDD) and diketopyrrolopyrrole (DPP) units with various molar ratios is developed. Compared with the benchmark PBDB-T donor containing BDD unit, additional incorporation of a stronger electron-negative DPP unit markedly lowers frontier molecular orbital levels and extends optical absorption, potentially leading to simultaneously enhanced VOC and JSC in organic solar cells.... (More)

High-performance polymer donors when paired with nonfullerene acceptors are mainly limited to flanking halogenated benzodithiophene (BDT)-based π-conjugated copolymers, which however involve complex synthetic procedures. Herein, a series of halogen-free polymer donors that link BDT moiety with two highly electron-deficient benzodithiophene-dione (BDD) and diketopyrrolopyrrole (DPP) units with various molar ratios is developed. Compared with the benchmark PBDB-T donor containing BDD unit, additional incorporation of a stronger electron-negative DPP unit markedly lowers frontier molecular orbital levels and extends optical absorption, potentially leading to simultaneously enhanced VOC and JSC in organic solar cells. A remarkable power conversion efficiency (PCE) of 10.28% is thus obtained in the optimal P75 (BDD : DPP = 3:1 mol%) and Y6 blend cells in comparison with the reference PBDB-T:Y6 (9.20%). A slight addition of PC71BM into the blend is found to further generate finer phase-separated domains and thus increase the best efficiency up to 12.20%. The subtly critical roles of PC71BM are determined by transient absorption measurements on both thin-film and in situ devices to be the prolonged free charge carrier lifetime and the shallow charge transfer states, which enhance JSC and fill factor in the device, respectively.

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author
; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
diketopyrrolopyrrole, halogen-free polymer donors, nonfullerene acceptors, organic solar cells, polymer donors
in
Solar RRL
volume
5
issue
5
publisher
Wiley-Blackwell
external identifiers
  • scopus:85103375316
ISSN
2367-198X
DOI
10.1002/solr.202100142
language
English
LU publication?
yes
id
832e4b80-00e5-485c-911f-b919ac247d01
date added to LUP
2021-04-14 08:39:10
date last changed
2023-11-08 12:46:02
@article{832e4b80-00e5-485c-911f-b919ac247d01,
  abstract     = {{<p>High-performance polymer donors when paired with nonfullerene acceptors are mainly limited to flanking halogenated benzodithiophene (BDT)-based π-conjugated copolymers, which however involve complex synthetic procedures. Herein, a series of halogen-free polymer donors that link BDT moiety with two highly electron-deficient benzodithiophene-dione (BDD) and diketopyrrolopyrrole (DPP) units with various molar ratios is developed. Compared with the benchmark PBDB-T donor containing BDD unit, additional incorporation of a stronger electron-negative DPP unit markedly lowers frontier molecular orbital levels and extends optical absorption, potentially leading to simultaneously enhanced V<sub>OC</sub> and J<sub>SC</sub> in organic solar cells. A remarkable power conversion efficiency (PCE) of 10.28% is thus obtained in the optimal P75 (BDD : DPP = 3:1 mol%) and Y6 blend cells in comparison with the reference PBDB-T:Y6 (9.20%). A slight addition of PC<sub>71</sub>BM into the blend is found to further generate finer phase-separated domains and thus increase the best efficiency up to 12.20%. The subtly critical roles of PC<sub>71</sub>BM are determined by transient absorption measurements on both thin-film and in situ devices to be the prolonged free charge carrier lifetime and the shallow charge transfer states, which enhance J<sub>SC</sub> and fill factor in the device, respectively.</p>}},
  author       = {{Ji, Jingjing and Xie, Jiaqi and Tang, Junhui and Zheng, Kaibo and Liang, Ziqi}},
  issn         = {{2367-198X}},
  keywords     = {{diketopyrrolopyrrole; halogen-free polymer donors; nonfullerene acceptors; organic solar cells; polymer donors}},
  language     = {{eng}},
  number       = {{5}},
  publisher    = {{Wiley-Blackwell}},
  series       = {{Solar RRL}},
  title        = {{Developing Halogen-Free Polymer Donors for Efficient Nonfullerene Organic Solar Cells by Addition of Highly Electron-Deficient Diketopyrrolopyrrole Unit}},
  url          = {{http://dx.doi.org/10.1002/solr.202100142}},
  doi          = {{10.1002/solr.202100142}},
  volume       = {{5}},
  year         = {{2021}},
}