Increasing the Strength, Hardness, and Survivability of Semiconducting Polymers by Crosslinking

Alexander X. Chen, Jeremy D. Hilgar, Anton A. Samoylov, Silpa S. Pazhankave, Jordan A. Bunch, Kartik Choudhary, Guillermo L. Esparza, Allison Lim, Xuyi Luo, Hu Chen, Rory Runser, Iain McCulloch, Jianguo Mei, Christian Hoover, Adam D. Printz, Nathan A. Romero, Darren J. Lipomi

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


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 languageEnglish (US)
Pages (from-to)2202053
JournalAdvanced Materials Interfaces
StatePublished - Dec 1 2022

Bibliographical note

KAUST Repository Item: Exported on 2022-12-06
Acknowledgements: 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


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