Developing Halogen-Free Polymer Donors for Efficient Nonfullerene Organic Solar Cells by Addition of Highly Electron-Deficient Diketopyrrolopyrrole Unit
(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.
(Less)
- author
- Ji, Jingjing ; Xie, Jiaqi ; Tang, Junhui ; Zheng, Kaibo LU and Liang, Ziqi
- organization
- publishing date
- 2021
- 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}}, }