Effect of Nonconjugated Spacers on Mechanical Properties of Semiconducting Polymers for Stretchable Transistors
Abstract
Nonconjugated segments in polymer semiconductors have been utilized to improve the processability of semiconducting polymers. Recently, several reports have described the improvement of stretchability of polymer semiconductors by incorporating nonconjugated spacers. However, the effect of relative flexibility of such conjugation breakers on mechanical and electrical properties has not yet been studied systematically. Here, conjugation breakers with different chain length and rigidity are incorporated into the backbone of diketopyrrolopyrrole‐based semiconductors. Interestingly, it is observed that the longer and more flexible conjugation breakers result in greater ductility and lower elastic modulus without significantly affecting mobility. The enhancement of stretchability is attributed to the reduced modulus and the decrease in crystallinity, as confirmed by X‐ray diffraction. With this newly established molecular design, transistors are prepared with a semiconducting polymer containing dodecyl segments as conjugation breakers. It is observed that this polymer retains a mobility of >0.36 cm2 V−1 s−1 at 100% strain, and after 100 cycles at 50% strain. Finally, its high stability against strain is also observed with a fully stretchable transistor fabricated. Taken together, the above results indicate that molecular engineering of conjugated polymers, i.e., by incorporating suitable conjugation breakers, can effectively tune mechanical properties without significantly compromising their electrical properties.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Sep 05, 2018
- Source ID
- 10.1002/adfm.201804222
Entities
People
- Franklin L Lee
- Franziska Lissel
- Ging‐ji Nathan Wang
- Hung‐chin Wu
- Jaewan Mun
- Jeffrey B.‐h. Tok
- Jiheong Kang
- Jin Young Oh
- Simon Rondeau‐gagné
- Toru Katsumata
- Zhenan Bao
Organizations
- Air Force Office of Scientific Research
- Asahi Kasei
- Fonds de Recherche du Québec Nature et technologies
- Kyung Hee University
- Leibniz Institute for Polymer Research
- National Science Foundation
- Stanford University
- Swiss National Science Foundation
- United States Department of Energy
- University of Windsor