Tuning Mechanical Properties of Polymer Semiconductor By Modulating Hydrogen Bonding Interactions

Authors

Yu Zheng, Stanford UniversityFollow
Minoru Ashizawa, Stanford University
Song Zhang, University of Southern MississippiFollow
Jiheong Kang, Stanford UniversityFollow
Shayla Nikzad, Stanford University
Zhiao Yu, Stanford UniversityFollow
Yuto Ochiai, Stanford University
Hung-Chin Wu, Stanford University
Helen Tran, Stanford University
Jaewan Mun, Stanford University
Yu-Qing Zheng, Stanford University
Jeffrey B.-H. Tok, Stanford UniversityFollow
Xiaodan Gu, University of Southern MississippiFollow
Zhenan Bao, Stanford UniversityFollow

Document Type

Article

Publication Date

6-1-2020

School

Polymer Science and Engineering

Abstract

Conjugation breakers (CBs) with different H-bonding chemistry and linker flexibility are designed and incorporated into a Diketopyrrolopyrrole (DPP)-based conjugated polymer backbone. The effects of H-bonding interactions on polymer semi-conductor morphology, mechanical properties and electrical performance are systematically investigated. We observe that CBs with H-bonding self-association constant >0.7 or denser packing tendency are able to induce higher polymer chain aggregation and crystallinity in as-casted thin film, resulting in higher modulus and crack on-set strain. Additionally, the rDoC (relative degree of crystallinity) of the stretched thin film with the highest crack on-set strain only suffers a small decrease, suggesting the main energy dissipation mechanism is the breakage of H-bonding interactions. By contrast, other less stretch-able polymer films dissipate strain energy through the breakage of crystalline domains, indicated by drastic decrease in rDoC. Furthermore, we evaluate their electrical performance under mechanical strain in fully stretchable field-effect transistors. The polymer with the highest crack on-set strain has the least degradation in mobility as a function of strain. Overall, these observations suggest that we can aptly tune the mechanical properties in polymer semiconductors by modulating intermolecular interactions, such as H-bonding chemistry and linker flexibility. Such understanding provides molecular design guidelines for future stretchable semiconductors.

Publication Title

Chemistry of Materials

Recommended Citation

Zheng, Y., Ashizawa, M., Zhang, S., Kang, J., Nikzad, S., Yu, Z., Ochiai, Y., Wu, H., Tran, H., Mun, J., Zheng, Y., Tok, J. B., Gu, X., Bao, Z. (2020). Tuning Mechanical Properties of Polymer Semiconductor By Modulating Hydrogen Bonding Interactions. Chemistry of Materials.
Available at: https://aquila.usm.edu/fac_pubs/17565