Abstract
Crosslinking is a ubiquitous strategy in polymer engineering to increase the thermomechanical robustness of solid polymers but has been relatively unexplored in the context of π-conjugated (semiconducting) polymers. Notwithstanding, mechanical stability is key to many envisioned applications of organic electronic devices. For example, the wide-scale distribution of photovoltaic devices incorporating conjugated polymers may depend on integration with substrates subject to mechanical insult—for example, road surfaces, flooring tiles, and vehicle paint. Here, a four-armed azide-based crosslinker (“4Bx”) is used to modify the mechanical properties of a library of semiconducting polymers. Three polymers used in bulk heterojunction solar cells (donors J51 and PTB7-Th, and acceptor N2200) are selected for detailed investigation. In doing so, it is shown that low loadings of 4Bx can be used to increase the strength (up to 30%), toughness (up to 75%), hardness (up to 25%), and cohesion of crosslinked films. Likewise, crosslinked films show greater physical stability in comparison to non-crosslinked counterparts (20% vs 90% volume lost after sonication). Finally, the locked-in morphologies and increased mechanical robustness enable crosslinked solar cells to have greater survivability to four degradation tests: abrasion (using a sponge), direct exposure to chloroform, thermal aging, and accelerated degradation (heat, moisture, and oxygen).
Original language | English (US) |
---|---|
Pages (from-to) | 2202053 |
Journal | Advanced Materials Interfaces |
DOIs | |
State | Published - Dec 1 2022 |
Bibliographical note
KAUST Repository Item: Exported on 2022-12-06Acknowledgements: This work was supported by the Air Force Office of Scientific Research (AFOSR) grant no. FA9550-22-1-0454. K.C. acknowledges additional support as a Hellman Scholar and an Intel Scholar provided through the Academic Enrichment Program (AEP) at UCSD through the following awards: The Undergraduate Research Scholarship and Semiconductor Research Corporation Scholarship. R.R. acknowledges support from the National Science Foundation Graduate Research Fellowship (NSF GRFP) under grant no. DGE-1144086. The authors acknowledge the use of facilities and instrumentation supported by NSF through the UC San Diego Materials Research Science and Engineering Center (UCSD MRSEC), grant DMR-2011924. This work was performed in part at the San Diego Nanotechnology Infrastructure (SDNI) of UCSD, a member of the National Nanotechnology Coordinated Infrastructure, which is supported by the National Science Foundation (Grant ECCS-2025752). The authors thank the Department of Chemistry and Biochemistry at The University of Arizona for support of the Laboratory for Electron Spectroscopy and Surface Analysis.
ASJC Scopus subject areas
- Mechanics of Materials
- Mechanical Engineering