A Molecular Design Approach Towards Elastic and Multifunctional Polymer Electronics

Yu Zheng, Stanford University
Zhiao Yu, Stanford University
Song Zhang, University of Southern Mississippi
Xian Kong, Stanford University
Wesley Michaels, Stanford University
Weichen Wang, Stanford University
Gan Chen, Stanford University
Deyu Liu, Stanford University
Jian Cheng Lai, Stanford University
Nathaniel Prine, University of Southern Mississippi
Weimin Zhang, King Abdullah University of Science and Technology
Shayla Nikzad, Stanford University
Christopher B. Cooper, Stanford University
Donglai Zhong, Stanford University
Jaewan Mun, Stanford University
Zhitao Zhang, Stanford University
Jiheong Kang, Stanford University
Jeffrey B.H. Tok, Stanford University
Iain McCulloch, King Abdullah University of Science and Technology
Jian Qin, Stanford University
Xiaodan Gu, University of Southern Mississippi
Zhenan Bao, Stanford University

Abstract

Next-generation wearable electronics require enhanced mechanical robustness and device complexity. Besides previously reported softness and stretchability, desired merits for practical use include elasticity, solvent resistance, facile patternability and high charge carrier mobility. Here, we show a molecular design concept that simultaneously achieves all these targeted properties in both polymeric semiconductors and dielectrics, without compromising electrical performance. This is enabled by covalently-embedded in-situ rubber matrix (iRUM) formation through good mixing of iRUM precursors with polymer electronic materials, and finely-controlled composite film morphology built on azide crosslinking chemistry which leverages different reactivities with C–H and C=C bonds. The high covalent crosslinking density results in both superior elasticity and solvent resistance. When applied in stretchable transistors, the iRUM-semiconductor film retained its mobility after stretching to 100% strain, and exhibited record-high mobility retention of 1 cm2 V−1 s−1 after 1000 stretching-releasing cycles at 50% strain. The cycling life was stably extended to 5000 cycles, five times longer than all reported semiconductors. Furthermore, we fabricated elastic transistors via consecutively photo-patterning of the dielectric and semiconducting layers, demonstrating the potential of solution-processed multilayer device manufacturing. The iRUM represents a molecule-level design approach towards robust skin-inspired electronics.