Efficient non-fullerene organic solar cells employing sequentially deposited donor–acceptor layers


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Type
Article
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Authors
Kan, Bin 
Pearson, Andrew 
Parnell, Andrew 
Cooper, Jos 
Abstract

Non-fullerene acceptors (NFAs) have recently outperformed their fullerene counterparts in binary bulk-heterojunction (BHJ) organic solar cells (OSCs). Further development of NFA OSCs may benefit other novel OSC device structures that alter or extend the standard BHJ concept. Here, we report such a new processing route that forms a BHJ-like morphology between sequentially processed polymer donor and NFA with high power conversion efficiencies in excess of 10%. Both devices show similar charge generation and recombination behaviours, supporting formation of similar BHJ active layers. We correlate the ~30 meV smaller open-circuit voltage in sq-BHJ devices to more substantial non-radiative recombination by voltage loss analysis. We also determine the exciton diffusion length of benchmark polymer PBDB-T to be 10 ± 3 nm. Our results demonstrate high-efficiency OSC devices using sequential deposition method and provide new opportunities to further improve performance of state-of-the-art OSCs.

Description
Keywords
40 Engineering, 3403 Macromolecular and Materials Chemistry, 4016 Materials Engineering, 34 Chemical Sciences, 7 Affordable and Clean Energy
Journal Title
Journal of Materials Chemistry A
Conference Name
Journal ISSN
2050-7496
2050-7496
Volume Title
6
Publisher
Royal Society of Chemistry (RSC)
Sponsorship
Engineering and Physical Sciences Research Council (EP/M005143/1)
EPSRC (1641842)
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