Polymer Solar Cells with 18.74% Efficiency: From Bulk Heterojunction to Interdigitated Bulk Heterojunction

The most popular approach to fabricating organic solar cells (OSCs) is solution processing a mixture of donor (D) and acceptor (A) materials into an active layer with a bulk heterojunction (BHJ) nanostructure. Herein, it is demonstrated that the interdigitated heterojunction (IHJ) is a more suitable...

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Bibliographic Details
Published in:Advanced functional materials 2022-01, Vol.32 (4), p.n/a
Main Authors: Xu, Xiaopeng, Yu, Liyang, Meng, Huifeng, Dai, Liming, Yan, He, Li, Ruipeng, Peng, Qiang
Format: Article
Language:English
Subjects:
Diffusion length
Energy conversion efficiency
Excitons
Free electrons
Heterojunctions
interdigitated heterojunctions
Mass production
Materials science
morphology
nanopores
Nanostructure
Photovoltaic cells
polymer solar cells
sequential deposition
Solar cells
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Summary:The most popular approach to fabricating organic solar cells (OSCs) is solution processing a mixture of donor (D) and acceptor (A) materials into an active layer with a bulk heterojunction (BHJ) nanostructure. Herein, it is demonstrated that the interdigitated heterojunction (IHJ) is a more suitable nanostructure of the active layer for high‐performance OSCs whereas it is a long standing challenge to realize well‐defined IHJ structures. In this study, a facile and versatile sequential solution processing method is developed to produce an IHJ nanostructure with power conversion efficiency reaching 18.74% (18.10% for BHJ the counterpart) by fabricating a donor film with nanopores created by a wax additive, sequentially casting the acceptor on top of infiltrating the nanopores. Compared to the BHJ, the IHJ structure with an interpillar distance within the exciton diffusion length can afford a large bulk D/A interface for efficient exciton dissociation with a minimized charge recombination while free electrons and holes can transport to the respective electrodes through more straightforward pathways, thus enhance performance. Furthermore, the D or A phase in the IHJ device contacts with only one electrode, which can prevent shunting between the anode and cathode and facilitate the industrial mass production of OSCs. An interdigitated bulk heterojunction structure of the active layer is developed by preforming the porous donor polymer film and then processing the acceptor on top, which yields an impressive high power conversion efficiency of 18.74% for polymer solar cells.
ISSN:1616-301X
1616-3028
DOI:10.1002/adfm.202108797