@inproceedings{0d92984de8db4fd6a136ac638aa5783c,
title = "Toward intrinsically stretchable organic semiconductors: Mechanical properties of high-performance conjugated polymers",
abstract = "This paper describes several approaches to understanding and improving the response of π-conjugated (semiconducting) polymers to tensile strain. Our principal goal was to establish the design criteria for introducing elasticity and ductility in conjugated (semiconducting) polymers through a rigorous analysis of the structural determinants of the mechanical properties of this type of material. We elucidated the details of the effect of the alkyl side chain length on the mechanical properties of regioregular polythiophene and used this analysis to select materials for stretching and transfer printing of organic solar cells to hemispherical substrates. This demonstration represents the first time that a conjugated polymer device has ever been stretched and conformally bonded to a complex 3D surface (i.e., other than a cone or cylinder, for which flexibility-as opposed to stretchability-is sufficient). We then further explored the details of the dependence of the mechanical properties on the side chain of a semiconducting polymer by synthesizing a series of hybrid materials (block and random copolymers) containing both short and long side chains. This analysis revealed the unusual semiconducting polymer, poly(3-heptylthiophene), as having an excellent combination of mechanical and electronic properties. In parallel, we explored a new method of producing {"}blocky{"} copolymers using a new procedure based on random segmentation of conjugated monomers. We found that introduction of structural randomness increased the elasticity without having detrimental effects on the photovoltaic performance. We also describe methods of synthesizing large volumes of conjugated polymers in environmentally benign ways that were amenable to manufacturing.",
keywords = "Bulk heterojunction, Conjugated polymer, Green chemistry, Mechanical properties, Organic solar cells, P3HT, PCBM, Polythiophene, Stretchable electronics, Transfer printing",
author = "Sawyer, {Eric J.} and Suchol Savagatrup and O'Connor, {Timothy F.} and Makaram, {Aditya S.} and Burke, {Daniel J.} and Zaretski, {Aliaksandr V.} and Printz, {Adam D.} and Lipomi, {Darren J.}",
note = "Publisher Copyright: {\textcopyright} 2014 SPIE.; Organic Field-Effect Transistors XIII; and Organic Semiconductors in Sensors and Bioelectronics VII ; Conference date: 18-08-2014 Through 20-08-2014",
year = "2014",
doi = "10.1117/12.2059098",
language = "English (US)",
series = "Proceedings of SPIE - The International Society for Optical Engineering",
publisher = "SPIE",
editor = "Iain McCulloch and Ioannis Kymissis and Zhenan Bao and Ruth Shinar",
booktitle = "Organic Field-Effect Transistors XIII; and Organic Semiconductors in Sensors and Bioelectronics VII",
}